JP5748204B2 - High frequency power supply - Google Patents

Description

  The present invention relates to a high frequency power supply apparatus that supplies high frequency power to a load such as a plasma processing apparatus.

  A high-frequency power supply device that supplies power to a load such as a plasma processing apparatus includes a high-frequency signal generation unit that generates a high-frequency signal having the same frequency as the high-frequency power supplied to the load, and power that amplifies the high-frequency signal generated by the high-frequency signal generation unit According to the detection signal obtained from the amplifying unit, the high-frequency detecting unit that separately detects the traveling wave power supplied to the load on the output side of the power amplifying unit and the reflected wave power returned from the load And a control unit for controlling the power amplification unit.

  The high-frequency detection unit usually includes a directional coupler inserted between the power amplification unit and the load, and a traveling wave detection signal indicating the traveling wave power given from the power amplification unit to the load, and reflected by the load. And a reflected wave detection signal indicating the reflected wave power returning to the power amplifier.

The control unit controls the power amplifying unit so that the traveling wave power output from the high frequency power supply device or the active power consumed by the load is kept within the set range, and when there is a large amount of reflected wave power returning from the load. In order to protect the semiconductor amplifying element constituting the power amplifying unit, protection control for suppressing the output of the power amplifying unit is performed. When a reflected wave is generated in the load, the effective power consumed by the load is obtained by subtracting the reflected wave power from the traveling wave power.

  A high-frequency power supply apparatus that supplies high-frequency power to a load such as a plasma processing apparatus needs to output high-purity high-frequency power (traveling wave power) that does not contain spurious frequency components other than the fundamental frequency. Therefore, in the high-frequency power supply device used for this type of application, various high-frequency filters for removing spurious frequency components are disposed at a required portion in a portion from the high-frequency signal generation unit to the output stage of the power amplification unit. . In addition, a low pass filter is connected to the output stage of the power amplification unit in order to pass only the fundamental frequency component. Therefore, the traveling wave power output from the power amplifying unit is substantially composed of only the fundamental frequency component, but the spurious frequency component is superimposed on the reflected wave power returning from the load as described later. Includes a spurious frequency component in the traveling wave power detected by the high frequency detector.

  An impedance matching unit is usually provided between the output of the high-frequency power supply and the load, and reflected wave power is generated at the load by matching the impedance with the load that is in a steady state. To prevent it. Therefore, when the load impedance does not show a sudden change in the steady state, the level of the traveling wave power given from the power amplification unit to the load is kept stable, and the reflected wave power reflected by the load and returning to the power amplification unit is It is the minimum.

  However, when a load such as a plasma processing apparatus is activated, the impedance of the load is in a non-linear state and fluctuates at a high speed. Therefore, the matching operation of the impedance matching device cannot catch up, and a reflected wave is generated with the load as a node. Furthermore, inside the load, various frequency components different from the fundamental frequency are generated as spurious frequency components due to the frequency mixing effect caused by the nonlinearity of the impedance, and these spurious frequency components are superimposed on the reflected wave power. Return to the high-frequency power supply.

  Moreover, when high frequency powers having different frequencies are simultaneously applied to the electrodes of the plasma processing apparatus, such as a plasma processing apparatus for etching a semiconductor wafer, the impedance of the load changes in a complicated manner. Therefore, even in a steady state, impedance matching cannot be completely achieved by the impedance matching device, and it is impossible to avoid generation of a reflected wave at the load. When supplying high-frequency power to a load having such a configuration, the fundamental frequency component and various spurious frequency components are superimposed on the reflected wave that returns from the load to the power amplification unit even in a steady state. In this way, when the reflected wave on which the spurious frequency component is superimposed returns, the reflected wave detection signal obtained from the high frequency detector includes a lot of spurious frequency components in addition to the fundamental frequency component. The traveling wave detection signal also includes a spurious frequency component.

  The term “spurious frequency” is sometimes used to mean an unnecessary frequency that appears before and after the fundamental frequency and an unnecessary frequency that appears before and after each harmonic frequency. In this specification, the term other than the fundamental frequency is used. All frequencies are referred to as spurious frequencies.

  In the state where the spurious frequency component is included in the traveling wave detection signal, the level of the fundamental frequency component of the traveling wave power cannot be detected accurately, so that the control for maintaining the traveling wave power within the set range must be performed accurately. I can't. Therefore, in the prior art, as shown in FIG. 4 of Patent Document 1, the spurious frequency component is removed by inputting the output of the traveling wave detection signal obtained from the high-frequency detector to the filter, or Patent Document 1 As shown in FIG. 1, the frequency of the traveling wave detection signal is converted to a frequency that facilitates the creation of the filter, and then input to the filter to remove spurious frequency components. In the high frequency power supply device shown in FIG. 1 of Patent Document 1, a local signal having a frequency different from the frequency of the high frequency power is generated in addition to the high frequency signal generating unit that generates a high frequency signal having the same frequency as the high frequency power applied to the load. By providing a local signal generator and mixing (multiplying) the traveling wave detection signal obtained from the high frequency detector and the local signal, the frequency of the traveling wave detection signal is set to a relatively low frequency at which filter creation is easy. After the conversion, the signal is input to a filter to remove spurious frequency components. A technique for removing spurious frequency components with a filter after performing frequency conversion by mixing the frequency of a detection signal of traveling wave power with a local signal is also disclosed in Patent Document 2.

  As described above, if the spurious frequency component can be removed from the traveling wave detection signal, control that keeps the fundamental frequency component of the traveling wave power output from the high-frequency power supply device within the set range, or an effective amount that is actually consumed by the load The power can be controlled accurately.

  When a reflected wave is generated in the load, the reflected wave power is combined with the traveling wave power on the transmission path connecting the power amplification unit and the load, so that a standing wave is generated on the transmission path. If the reflected wave power is large and a high level standing wave (power, voltage and current) is generated, the voltage applied to the semiconductor amplifying element of the power amplifying unit becomes excessive, and the semiconductor amplifying element is deteriorated or damaged. There is a risk of doing so. In order to prevent such a problem from occurring, as shown in Patent Document 3, when the reflected wave power detected by the high-frequency detection unit exceeds a limit value, the output of the power amplification unit is suppressed. When the protection control is performed or the total value of the traveling wave power and the reflected wave power detected by the high frequency detection unit exceeds the limit value as shown in Patent Document 4, the output of the power amplification unit It is necessary to protect the semiconductor amplifying element by performing protection control for suppressing the above.

  As described above, the control unit of the high-frequency power supply device includes the output control for controlling the power amplification unit so as to keep the traveling wave power output by the high-frequency power or the effective power obtained by subtracting the reflected wave power from the traveling wave power within the set range. When the reflected wave power returning from the load is large, protection control is performed to suppress the output of the power amplifier so that the reflected wave power or the total value of the traveling wave power and the reflected wave power does not exceed the limit value. Although configured as described above, the control characteristics to be given to the high-frequency power supply device that is actually shipped are determined according to the specifications required by the user.

  For example, in the output control, when it is important to keep the traveling wave power output from the high frequency power supply device within the set range, the fundamental frequency component of the traveling wave power is detected from the traveling wave detection signal obtained from the high frequency detection unit. The control unit is configured to perform output control that keeps the detected fundamental frequency component of the traveling wave power within the set range. Also, when placing importance on keeping the high-frequency power actually consumed by the load within the set range, the reflected wave power is treated as reactive power, and the reflected wave power is subtracted from the fundamental frequency component of the traveling wave power. Output control is performed so as to keep the active power within the set range. In this case, only the fundamental frequency component may be used as the reflected wave power to be subtracted from the fundamental frequency component of the traveling wave power, or the reflected wave power including both the fundamental frequency component and the spurious frequency component that cannot be ignored may be used. is there.

  In the protection control that suppresses the output of the power amplifier when the total value of the traveling wave power and the reflected wave power exceeds the limit value, the reflected wave power added to the fundamental frequency component of the traveling wave power is reflected as the reflected wave power. There are a case where only the fundamental frequency component of the wave power is used and a case where the total reflected wave power including both the fundamental frequency component and the spurious frequency component is used for safety.

  As described above, in the high frequency power supply device, the content of the control performed by the control unit is determined according to the specification required by the user. However, in order to facilitate the manufacture of the device, any specification required by the user is used. It is necessary to be able to cope with. For that purpose, it is necessary to be able to accurately detect the fundamental frequency component of the traveling wave power, as well as to be able to accurately detect the fundamental frequency component of the reflected wave power. is there. In addition, when it is necessary to monitor the spurious frequency component on the high frequency power supply device for the purpose of monitoring the load status, it is necessary to be able to detect the spurious frequency component to be monitored independently. There is.

  When detecting the fundamental frequency components of the traveling wave power and the reflected wave power, various techniques are introduced according to the required detection accuracy. For example, in the high frequency power supply device disclosed in Patent Document 1 or Patent Document 2 described above, a local signal generator is provided in addition to the high frequency signal generator that generates a high frequency signal to be input to the power amplifier. By mixing the detection signal obtained from the detection unit and the local signal, the frequency of the detection signal is converted to a relatively low frequency that facilitates frequency separation processing (easy to create a filter), and then the filter is A process for separating the fundamental frequency component is performed to detect the fundamental frequency component of the traveling wave power with high accuracy.

  Further, as shown in Patent Document 6, the fundamental frequency component of the traveling wave detection signal is obtained by multiplying the reference high frequency signal and the traveling wave detection signal, which have the same frequency as the high frequency power supplied to the load, in phase with each other. A technique has also been proposed in which fundamental frequency components are detected with high accuracy by directly converting the signal into a direct current component. In the example shown in Patent Document 6, a reference high-frequency signal having the same frequency as the high-frequency power supplied to the load is obtained by demultiplexing a part of the high-frequency signal supplied from the high-frequency signal generation unit to the power amplification unit, By multiplying the reference high-frequency signal and the traveling wave detection signal obtained from the high-frequency detection unit in phase, a signal including a direct current component proportional to the fundamental frequency component of the traveling wave power is generated, and this signal is low-pass filtered. The fundamental frequency component of the traveling wave power is detected by extracting the direct current component. The method of detecting the fundamental frequency component in this way is called a direct detection method (homodyne method) as opposed to the frequency conversion method (heterodyne method).

 Further, as shown in Patent Document 3 and Patent Document 5, the detection signal extracted from the high-frequency detection unit is supplied to the bandpass filter without performing frequency conversion or direct detection, and unnecessary frequency is detected from the detection signal. In some cases, a method of extracting a fundamental frequency component by removing the component is employed.

JP 2010-108839 A JP 2003-179030 A Japanese Patent Laid-Open No. 11-233294 JP 2008-276966 A JP-A-5-63627 JP 2010-238493 A

  As described above, in a high-frequency power supply apparatus that supplies high-frequency power to a load such as a plasma processing apparatus, even if many spurious frequency components flow backward from the load, the traveling-wave power supplied to the load or the load actually Therefore, it is necessary to make it possible to accurately and stably perform output control that keeps the active power consumed within a set range. Also, power amplification when the reflected wave power or the total value of the traveling wave power and the reflected wave power exceeds the limit value so that the semiconductor amplifying element is not deteriorated or damaged when the reflected wave power is high. It is necessary to ensure that protection control for suppressing the output of the unit can be performed accurately. Therefore, in a high frequency power supply apparatus that supplies high frequency power to a load such as a plasma processing apparatus, it is necessary to be able to accurately detect the fundamental frequency component of traveling wave power and the fundamental frequency component of reflected wave power. Further, it is preferable that the spurious frequency component can be accurately detected in order to meet the demand for monitoring the load condition on the power supply device side.

  When an analog filter is used to detect the fundamental frequency component of the traveling wave power and the fundamental frequency component of the reflected wave power by removing the spurious frequency component from the traveling wave detection signal and the reflected wave detection signal, it depends on the ambient temperature. Since the transmission characteristics of the filter change, it is difficult to completely remove spurious frequency components. When the spurious frequency component cannot be sufficiently removed, the output control of the high frequency power supply device is performed when there are many spurious frequency components superimposed on the reflected wave power, such as when high frequency power of two or more frequencies is simultaneously supplied to the load. Cannot be performed with high accuracy, and high frequency power cannot be stably supplied to the load.

  If a digital filter is used as a filter for removing the spurious frequency component from the traveling wave detection signal and the reflected wave detection signal and detecting the fundamental frequency component of the traveling wave power and the fundamental frequency component of the reflected wave power, digital arithmetic processing is performed. Thus, it is possible to avoid the influence of the change in the ambient temperature, to realize a narrow band of the filter, to sufficiently remove the spurious frequency component and to detect the fundamental frequency component with high accuracy. However, since a digital filter requires a multistage multiplier at high speed, the burden on hardware is heavy, the circuit configuration is complicated, and the cost is unavoidably increased. In addition, when a digital filter is used, it takes time to perform multi-stage arithmetic processing, so it is inevitable that control responsiveness deteriorates. Therefore, we want to avoid using digital filters as much as possible.

  As shown in Patent Documents 1 and 2, when detecting the fundamental frequency component of the traveling wave power and the fundamental frequency component of the reflected wave power by removing the spurious frequency component from the traveling wave detection signal and the reflected wave detection signal, If frequency conversion is performed, the fundamental frequency components of traveling wave power and reflected wave power can be detected with high accuracy. However, in order to perform frequency conversion, it is necessary to provide a local signal generation unit in the detection unit, and a narrowband filter is required to remove spurious frequency components from the frequency-converted signal. In addition to the complexity of the structure, it is unavoidable to increase the size. In addition, when performing frequency conversion, it is necessary to provide a plurality of signal generators. Therefore, it is necessary to remove interference between signal generators or to take measures against noise interference. Requires advanced technology for manufacturing.

  In detecting the fundamental frequency component of the traveling wave power, as shown in Patent Document 6, if the direct detection method is adopted, the fundamental frequency component can be detected as a DC signal. Separation from other signal components can be easily performed, and the configuration of the filter can be simplified. However, the high-frequency power supply device disclosed in Patent Document 6 cannot detect the fundamental frequency component of the reflected wave power, and cannot independently detect the spurious frequency component superimposed on the reflected wave power. .

  In order to detect a fundamental frequency component as a direct current component by a direct detection method from a signal in which a spurious frequency component is superimposed on the fundamental frequency, the phase of the signal to be detected needs to be constant. If the phase of the reflected wave power returning from the load is constant, direct detection is performed by multiplying the reflected wave detection signal and the reference high frequency signal in phase according to the suggestion of the invention disclosed in Patent Document 6. It is possible. However, in actuality, the phase of the reflected wave takes different values depending on the installation conditions and the like, and is not constant. Therefore, it is difficult to multiply the reference high frequency signal and the reflected wave detection signal in phase. Therefore, it is difficult to detect the fundamental frequency component of the reflected wave power by the direct detection method.

  As described above, since the fundamental frequency component of the reflected wave power cannot be detected in the apparatus shown in Patent Document 6, the effective power obtained by subtracting the fundamental frequency component of the reflected wave power from the fundamental frequency component of the traveling wave power is set in the setting range. Output control to keep the output of the power amplifying unit in such a way that the total value of the fundamental frequency component of the traveling wave power and the fundamental frequency component of the reflected wave power does not exceed the limit value. Can not cope with the case. In addition, since the apparatus disclosed in Patent Document 6 cannot detect only spurious frequency components, if there is a request to detect spurious frequency components for the purpose of monitoring the load state, the request is met. I can't respond.

  Recently, it has been demanded that high-frequency power having a sinusoidal waveform is modulated into a pulse waveform having a repetition period of 1 msec to 100 μsec and output. In order to accurately control output and protection when high frequency power is modulated into a pulse waveform, the fundamental frequency components of traveling wave power and reflected wave power can be detected at a sufficiently high detection speed. There is a need. If the detection speed of the traveling wave power and reflected wave power is slow, the detection operation cannot follow the sudden amplitude change at the rise and fall of the pulse, so the waveform becomes dull or ringing, The pulse waveform of the high frequency power collapses, and the high frequency power having the normal pulse waveform cannot be supplied to the load. In particular, when the pulse repetition period is 300 μsec or less, waveform distortion such as blunting of the pulse and ringing occurs remarkably due to detection delay of the high frequency power. In addition, if the detection speed of traveling wave power and reflected wave power is low, the protection control cannot be performed quickly, so that the semiconductor amplifying element may not be damaged.

  Therefore, when controlling a high-frequency power supply device that outputs high-frequency power of a pulse waveform, it is necessary to consider that the detection speed of traveling wave power and reflected wave power does not slow down, and the elements constituting the control device It is necessary to use an expensive one that is fast in processing.

  An object of the present invention is to provide a fundamental frequency component of traveling wave power given to a load, a fundamental frequency component of reflected wave power returning from the load, a fundamental frequency component and a spurious frequency component without imposing a heavy burden on hardware. When supplying reflected wave power including both and spurious frequency components individually, with high accuracy and sufficiently high detection speed, and supplying high frequency power with a continuous sinusoidal waveform to the load Output control and protection control can be performed accurately and stably, and even when high-frequency power supplied to a load is modulated into a pulse waveform, output control and protection control can be performed without causing waveform distortion. An object of the present invention is to provide a high-frequency power supply device that can be accurately and stably performed.

  The present invention includes a high-frequency signal generator that generates a high-frequency signal having a sinusoidal waveform, an amplifier that amplifies the high-frequency signal and outputs high-frequency power, and a level adjuster that adjusts the output level of the amplifier according to the output control signal; A power amplifying unit having a protection control unit that suppresses the output of the amplifier circuit according to the protection control signal, and a traveling wave detection signal and a reflected wave detection signal by detecting traveling wave power and reflected wave power from the output of the power amplification unit A high-frequency detection unit that outputs a signal, and an output control signal is given to the power amplification unit so as to keep the control target power component detected from the traveling wave detection signal and the reflected wave detection signal at a set value, and the traveling wave detection signal and the reflected wave detection A high-frequency power supply apparatus including a control unit that supplies the protection control signal to a power amplification unit so as to keep a monitoring target power component detected from a signal below a limit value.

In the present invention, the control unit demultiplexes a part of the high-frequency signal input from the high-frequency signal generation unit to the level adjustment unit to obtain a reference high-frequency signal having the same waveform and frequency as the high-frequency power supplied to the load. A phase difference between the reference high-frequency signal generation unit, a phase correction unit that corrects the phase difference between the traveling wave detection signal and the reference high-frequency signal to a value other than nπ / 2 (n is an odd number equal to or greater than 1), and the phase correction unit. A first multiplying unit that multiplies the traveling wave detection signal corrected with respect to the reference high-frequency signal, and all frequency components other than the fundamental frequency component of the high-frequency power as spurious frequency components, and a reflected wave detection signal or reflected wave detection A second multiplication unit that multiplies the processing target reflected wave detection signal and the reference high frequency signal by using, as a processing target reflected wave detection signal, a signal obtained by removing spurious frequency components not targeted for detection from the signal; A first signal generator to obtain a first analog signal having one of a level corresponding to the level of the fundamental frequency component of the forward power to extract a DC component from the output of the multiplication unit, among the spurious frequency components, detecting The spurious frequency component that is the target of the detection is the spurious frequency component to be detected, and is included in the high frequency side set frequency band that is set to include the frequency component that is twice the direct current component and the fundamental frequency from the output of the second multiplier to remove the frequency component, a second signal generator for obtaining a second analog signal having a level corresponding to the level of the total detected spurious frequency components contained in the processed reflected wave detection signal, processing the object reflector Corresponds to the level of the reflected wave power component of all detection targets including the fundamental frequency component and all spurious frequency components included in the detection target reflected wave detection signal by detecting the wave detection signal A third signal generation unit for obtaining a third analog signal having the above-mentioned level, and a first signal for converting the levels of the first analog signal to the third analog signal to the first digital value to the third digital value, respectively. The third A / D converter and the control target power component and the monitoring target power component are obtained from the first digital value to the third digital value, and the obtained control target power component is maintained at the set value. A digital arithmetic processing unit that outputs an output control signal and outputs a protection control signal so as to suppress the monitored power component to a limit value or less when the calculated monitored power component exceeds the limit value Yes. The digital arithmetic processing unit outputs a fundamental frequency component of traveling wave power obtained from the first digital value and a fundamental frequency component of reflected wave power obtained from a value obtained by subtracting the second digital value from the third digital value. The active power component obtained by subtracting from the fundamental frequency component of the traveling wave power obtained from the digital value of the current, or the total detected object reflected wave power component obtained from the third digital value is obtained from the first digital value. The active power component obtained by subtracting from the fundamental frequency component of the wave power is obtained as the control target power component, and the second digital is obtained from the fundamental frequency component of the traveling wave power obtained from the first digital value and the third digital value. The total value of the fundamental frequency components of the reflected wave power obtained from the value obtained by subtracting the value, and the fundamental circumference of the traveling wave power obtained from the first digital value The total value of all the detection target reflected wave power components obtained from the several components and the third digital value, only the fundamental frequency component of the reflected wave power, or all the detection target reflected wave power components are obtained as the monitoring target power components. Composed.

  When the traveling wave detection signal having a sine waveform and the reference high-frequency signal are input to the first multiplication unit and multiplied, the output signal of the first multiplication unit includes a traveling wave power when the phase of both signals does not change. A direct current component proportional to the fundamental frequency component and a frequency component twice the fundamental frequency are included. Therefore, when the direct current component is extracted from the output of the first multiplier, the fundamental frequency component of the traveling wave power can be detected.

  As will be described later, the magnitude (absolute value) of the direct current included in the output of the first multiplication unit varies depending on the phase difference between the traveling wave detection signal and the reference high frequency signal. The magnitude of the DC component included in the output of the first multiplier is maximized when the phase difference between the traveling wave detection signal and the reference high frequency signal is zero or mπ (m is an integer of 1 or more). When the phase difference is nπ / 2 (n is an odd number of 1 or more), the phase difference becomes zero. Therefore, by setting the phase difference between the traveling wave detection signal and the reference high frequency signal to a magnitude other than nπ / 2, the fundamental frequency component of the traveling wave power can be detected, and the phase difference between both signals can be determined. By setting to zero or mπ, the fundamental frequency component of traveling wave power can be detected with maximum sensitivity.

  As described above, since the output of the first multiplication unit can include a direct current component proportional to the fundamental frequency component of the traveling wave power, the first signal generation unit outputs the direct current component from the output of the first multiplication unit. By extracting the direct current component, a first analog signal indicating the fundamental frequency component of the traveling wave power can be obtained, and the level of this analog signal is converted into a digital value by the first A / D converter. The first digital value indicating the level of the fundamental frequency component of the traveling wave power can be obtained. Since the first analog signal is a direct current signal, output control and protection control can be performed without delay even if inexpensive hardware having a low conversion speed is used as hardware constituting the first A / D converter. The conversion data can be obtained at a sufficient speed necessary for the execution. Also, the DC component can be easily extracted using an analog low-pass filter, so there is no need to use an expensive filter to detect the fundamental frequency component of the traveling wave power, and the burden on the hardware is reduced. Thus, the configuration of the apparatus can be simplified.

  A reflected wave detection signal or a signal obtained by removing a spurious frequency component that is not a detection target from the reflected wave detection signal is used as a processing target reflected wave detection signal, and the processing target reflected wave detection signal and the reference high-frequency signal are used as a second multiplier. Is multiplied by the DC component of the level proportional to the maximum amplitude of the fundamental frequency component of the reflected wave power, the frequency component twice the fundamental frequency, and each spurious frequency component is the frequency and the frequency of the reference high frequency signal. A frequency component converted to a difference frequency (referred to as a difference frequency conversion component) and a frequency component obtained by frequency-converting each spurious frequency component to the sum of the frequency and the frequency of the reference high-frequency signal (sum frequency) Conversion component)). If any one of these frequency-converted frequency components is detected, either the difference frequency conversion component or the sum frequency conversion component is detected, all detection target spurious frequency components (detection targets) included in the reflected wave power are detected. All spurious frequency components) can be detected. Therefore, if the DC component and the frequency component included in the high frequency side set frequency band set so as to include the frequency component twice the fundamental frequency are removed from the output of the second multiplier, the reflected wave detection target to be processed is detected. A second analog signal having a level corresponding to the level of all spurious frequency components to be detected included in the signal can be obtained, and the level of the second analog signal is converted into a digital value by the second A / D converter. By converting, it is possible to obtain a second digital value indicating the level of all detection target spurious frequency components included in the processing target reflected wave detection signal.

  The second signal generation unit simply removes the DC component and the frequency component twice the fundamental frequency and detects the level to detect the DC component from the output signal of the second multiplication unit. Is not performed, the DC component may be zero. Therefore, the phase difference between the reflected wave detection signal to be processed and the reference high-frequency signal may be nπ / 2 (n is an odd number equal to or greater than 1), and the reflected wave detection signal to be processed and the reference high-frequency signal are multiplied by the second multiplication. It is not necessary to adjust the phase difference between the two signals when multiplying by the unit.

  On the other hand, when the third signal generation unit detects the processing target reflected wave detection signal and detects its level, all the detection target reflected waves including both the fundamental frequency component and the spurious frequency component included in the processing target reflected wave detection signal are detected. A third analog signal having a level corresponding to the level of the power component can be obtained, and the third A / D converter converts the level of the third analog signal into a digital value. A third digital value indicating the level of all the detection target reflected wave power components including both the fundamental frequency component and all the detection target spurious frequency components included in the wave detection signal can be obtained. Since the third analog signal is also a direct current signal, output control and protection control can be performed without delay even if inexpensive hardware having a low conversion speed is used as hardware constituting the third A / D conversion unit. Conversion data can be obtained at a sufficient speed necessary for the detection, and the detection target reflected wave power component can be detected at a high speed.

  As described above, the fundamental frequency component of traveling wave power, the total detection target spurious frequency component included in the reflected wave power, and the total detection target reflected wave power component including both the fundamental frequency component and the total detection target spurious frequency component. When the first digital value, the second digital value, and the third digital value respectively shown can be obtained, the fundamental frequency component of the traveling wave power can be known from the first digital value, and the third digital value is obtained. From the value obtained by subtracting the second digital value from the fundamental frequency component of the reflected wave power can be obtained.

  Further, if configured as described above, at least the first A / D conversion unit and the third A / D conversion unit need only be A / D converted from the DC signal, and are configured using inexpensive hardware. And cost can be reduced.

  In a preferred aspect of the present invention, the second signal generation unit is included in a high frequency side set frequency band set so as to include a frequency component that is twice the direct current component and the fundamental frequency from the output of the second multiplication unit. Configured to obtain a DC second analog signal having a level corresponding to the level of all detection target spurious frequency components included in the processing target reflected wave detection signal. .

If the second signal generation unit is configured in this way, the second A / D conversion unit may also perform A / D conversion of the DC signal, and can be configured using inexpensive hardware .

In a preferred aspect of the present invention , the digital arithmetic processing unit obtains a fundamental frequency component of traveling wave power obtained from the first digital value, and a value obtained by subtracting the second digital value from the third digital value. The active power component obtained from the value obtained by subtracting from the active power component obtained from the value obtained by subtracting the third digital value from the first digital value is calculated as the control target power component according to the external command. Configured.

When configured as described above, the control target power component can be easily changed by an external command, so that a high-frequency power supply device that meets the specifications required by the user can be easily configured .

In a preferred aspect of the present invention , the digital calculation processing unit obtains the reflected wave obtained by subtracting the second digital value from the value of the fundamental frequency component of the traveling wave power indicated by the first digital value and the third digital value. The total value of the fundamental frequency component value of power or the total value of the fundamental wave component of traveling wave power indicated by the first digital value and the reflected wave power component of all detection targets indicated by the third digital value is monitored. The power component is configured to be calculated according to an external command.

  When configured as described above, the power component to be monitored can be easily changed, so that a high-frequency power supply device that meets the specifications required by the user can be easily configured.

  In a preferred aspect of the present invention, a reference high-frequency signal level detection unit for detecting the level of the reference high-frequency signal is provided, and the high-frequency signal is maintained so that the level of the reference high-frequency signal detected by the reference high-frequency signal level detection unit is kept constant. A high-frequency signal control loop for controlling the generator is configured.

  If such a control loop is configured, the level of the high-frequency signal and the level of the reference high-frequency signal can be kept constant, so that the control can be performed stably.

  The high-frequency signal generator may be configured to output a continuous sinusoidal high-frequency signal, or may be configured to modulate a sinusoidal high-frequency signal into a pulse waveform and output the pulse waveform.

  In the present invention, since the fundamental frequency component of traveling wave power, the fundamental frequency component of reflected wave power, and the reflected wave power component of all detection targets can be detected at high speed, even if a high frequency signal is modulated into a pulse waveform, the response Output control and protection control can be performed without hindrance without causing a delay.

  The high-frequency signal generator may consist of a stable oscillator such as a crystal oscillator, and consists of a DDS (Direct Digital Synthesizer) that generates a high-frequency signal having the amplitude and frequency as instructed by the digital signal. Also good. If DDS is used, it is possible to easily cope with a change in the frequency of the high-frequency power.

 According to the present invention, a reference high-frequency signal having the same waveform and frequency as that of the high-frequency signal is obtained by demultiplexing a part of the high-frequency signal, and direct wave detection is performed using this reference high-frequency signal, thereby making it possible to determine the fundamental of traveling wave power. Since the frequency component is detected, there is no need to provide a local signal generator in addition to the high frequency signal generator as in the case of frequency conversion, and the hardware configuration can be simplified. In addition, since only a high-frequency signal generator needs to be provided as a signal generator, there is a need to take measures to prevent interference between the signal generators and to take advanced noise countermeasures and to operate the signal generator synchronously. The circuit configuration can be simplified and manufacturing can be facilitated.

  According to the present invention, a reflected wave detection signal or a signal obtained by removing a spurious frequency component not to be detected from the reflected wave detection signal is used as a processing object reflected wave detection signal. By removing the DC component from the signal obtained by multiplying the frequency component and the frequency component included in the high frequency side set frequency band set so as to include the frequency component twice the fundamental frequency, all spurious frequencies to be detected are detected. A second digital value indicating the level of all the detection-target spurious frequency components is obtained by obtaining a second analog signal having a level corresponding to the level of the component and converting the level of the second analog signal into a digital value. Therefore, it is possible to detect all spurious frequency components to be detected with high accuracy and to monitor spurious frequency components. Can.

  Further, according to the present invention, the third analog signal having a level corresponding to the level of the total detection target reflected wave power including both the fundamental frequency component and the spurious frequency component is detected by detecting the processing target reflected wave detection signal. After obtaining, the third analog signal level is digitally converted to obtain a third digital value indicating the level of the reflected wave power of all detection targets including both the fundamental frequency component and the spurious frequency component. Since the fundamental frequency component of the reflected wave power is detected by subtracting the second digital value indicating the spurious frequency component from the digital value of 3, the fundamental frequency of the reflected wave power can be detected without using a narrowband filter. The component can be detected accurately. Therefore, it is possible to accurately detect the fundamental frequency components of traveling wave power and reflected wave power and maintain the effective power within the set range without imposing a heavy burden on hardware, such as using a digital filter that performs complex arithmetic processing. The control and the protection control for controlling the power amplifying unit so that the total value of the traveling wave power and the reflected wave power does not exceed the limit value can be performed with high accuracy.

  Further, according to the present invention, the A / D converter that performs A / D conversion on at least the first analog signal and the third analog signal respectively converts the DC signal into A / D conversion. It is possible to detect the power component to be controlled and the power component to be monitored at high speed without applying power, and to perform output control and protection control with a high response speed, and to supply high frequency power with a continuous sinusoidal waveform to the load. Output control and protection control can be performed accurately and stably, and even when high-frequency power supplied to a load is modulated into a pulse waveform, the hardware configuration becomes complicated or waveform distortion occurs. The output control and the protection control can be performed accurately and stably without causing them to occur.

  According to the present invention, since the first and second multiplication units, at least the first and third A / D conversion units and the digital arithmetic processing unit can be speeded up, the control responsiveness can be improved. Hardware can be configured by using easily available and low-cost parts, and it is possible to cope with various specifications that require low cost and high control responsiveness.

  In particular, when the second analog signal generator is configured to generate the second analog signal as a DC signal, all of the first to third A / D converters are low in conversion speed. Since it can be configured using cost hardware, the cost can be reduced.

  In the present invention, a reference high-frequency signal level detector for detecting the level of the reference high-frequency signal is provided, and the high-frequency signal generator is controlled so as to keep the level of the reference high-frequency signal detected by the reference high-frequency signal level detector constant. When the high-frequency signal control loop is configured, the levels of the high-frequency signal and the reference high-frequency signal can be kept constant, so that the control can be performed stably.

  Further, the fundamental frequency component of traveling wave power obtained from the first digital value, the active power component obtained from the value obtained by subtracting the second digital value from the third digital value from the first digital value, and When the digital arithmetic processing unit is configured to calculate one of the active powers obtained from the value obtained by subtracting the third digital value from the first digital value as a control target power component according to an external command, Since it is possible to easily change the target power component, it is possible to easily configure a high-frequency power supply device that meets the specifications required by the user.

  Further, the total value of the fundamental frequency component of the traveling wave power obtained from the first digital value and the fundamental frequency component of the reflected wave power obtained from the value obtained by subtracting the second digital value from the third digital value, Or, the total value of the fundamental frequency component value of the traveling wave power obtained from the first digital value and the reflected wave power component of all the detection targets obtained from the third digital value is calculated according to the external command as the monitoring target power component. When the digital arithmetic processing unit is configured as described above, it is possible to easily change the power component to be monitored, and thus it is possible to easily configure a high-frequency power supply device that meets the specifications required by the user.

It is the block diagram which showed the structure of one Embodiment of this invention. It is the block diagram which showed the structure of other embodiment of this invention. It is the block diagram which showed the example of a structure of the function implementation means comprised by the digital arithmetic processing part in embodiment of this invention. It is the frequency characteristic figure which showed an example of the characteristic of the low-pass filter used by embodiment of this invention. It is the frequency characteristic figure which showed an example of the characteristic of the band pass filter used by embodiment of this invention. It is the frequency characteristic figure which showed an example of the characteristic of the other band pass filter used by embodiment of this invention. (A) And (B) is the wave form diagram which showed typically the example from which the output waveform of a high frequency power supply device differs.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 shows an overall configuration of an embodiment of the present invention. In FIG. 1, reference numeral 1 includes a central processing unit CPU, a nonvolatile memory such as a ROM or an EEPROM, a primary storage memory RAM, and the like. It is a digital arithmetic processing unit constituted by a microprocessor. The arithmetic processing unit is controlled based on the reference clock signal generated by the reference clock generating unit 2 and constitutes a function realizing unit that performs various functions by executing a program stored in the nonvolatile memory. The digital arithmetic processing unit 1 exchanges signals with the outside through the interface 3.

  4 is a high-frequency signal generating unit that generates a high-frequency signal having the frequency and amplitude as instructed by the frequency command and amplitude command given from the digital arithmetic processing unit 1, and 5 is a high-frequency signal generated by the high-frequency signal generating unit 4. A demultiplexer that demultiplexes the signal and outputs a high-frequency signal Sh1 and a reference high-frequency signal Sh2, and 6 is a power amplifying unit that amplifies the high-frequency signal Sh1 output from the demultiplexer 5 and outputs high-frequency power.

  The illustrated power amplifier 6 includes an amplifier circuit 601 that amplifies the high-frequency signal Sh1 and outputs high-frequency power, a level adjuster 602 that adjusts the output level of the amplifier circuit according to the output control signal SL, and a protection control signal Sp. And a protection control unit 603 for performing control to suppress the output of the amplifier circuit according to the above. The level adjustment unit 602 shown in the figure is inserted between the duplexer 5 and the amplification circuit 601 and amplifies the signal by adjusting the level of the high-frequency signal input to the amplification circuit 601 according to the output control signal SL. The level of the high frequency power output from the circuit 601 is adjusted. The protection control signal Sp is a signal for instructing the amount of suppression of the output of the amplifier circuit 601, and the protection control unit 603 reduces or amplifies the gain of the amplifier circuit 601 while the protection control signal Sp is applied. By reducing the power supply voltage of the circuit 601, control is performed to suppress the output of the amplifier circuit 601 by the amount of suppression indicated by the protection control signal.

  Although not shown, a filter for removing spurious frequency components is connected to the output stage of the power amplifying unit 6 as in the conventional high-frequency power supply device, and spurious frequency components generated in the amplifier circuit 601 and the like are Consideration is given so as not to output from the amplifying unit 6.

  Reference numeral 8 denotes a high-frequency detector that detects the traveling wave power applied to the load 9 and the reflected wave power returned from the load 9 on the output side of the power amplifier 6. The high-frequency detector 8 is composed of a directional coupler, and passes most of the high-frequency power output from the power amplifier 6 toward the load and returns from the traveling wave power supplied to the load and the load. The reflected wave power is separated and detected, and the traveling wave detection signal Sf and the reflected wave detection signal Sr are output.

  In the present embodiment, a reference high frequency signal generation unit 10 is configured by the duplexer 5, and a reference high frequency signal Sh 2 output from the reference high frequency signal generation unit is input to the first multiplication unit 11. The traveling wave detection signal Sf is also input to the first multiplication unit 11 through the phase correction unit 12, and the reference high-frequency signal Sh2 and the traveling wave detection signal Sf whose phase is corrected by the phase correction unit 12 are the first. Multiplication is performed by the multiplication unit 11. The output signal of the first multiplication unit 11 is input to the first signal generation unit 13 configured by a low-pass filter (LPF) made of an analog filter, and is output from the first signal generation unit 13. The signal S 1 is input to the digital arithmetic processing unit 1 through the first A / D conversion unit 14.

The amplitude of the reference high-frequency signal Sh2 input to the first multiplier 11 is A, the angular frequency is ω, the phase angle is α, the time is t, and the reference high-frequency signal is expressed as Sh2 = Asin (ωt−α). When the amplitude of the wave detection signal Sf is B, the angular frequency is ω, the phase angle is β, the time is t, the traveling wave detection signal is represented by Sf = sin (ωt−β), and the multiplication symbol is *, the first The output of the multiplication unit 11 is given by the following equation.
Asin (ωt-α) * Bsin (ωt-β)
= (A * B / 2) [cos (α−β) −cos {2ωt− (α + β)}] (1)

  Assuming that the phase angles α and β are constant, cos (α−β) is a constant, and (A * B / 2) * cos (α−β) in the above equation is a direct current component. That is, when the phase angles α and β are constant, the output signal of the first multiplier 11 is composed of a direct current component and a frequency component twice the fundamental frequency. Here, if the level A of the reference high frequency signal is constant, the direct current component is proportional to the maximum value B of the amplitude of the fundamental frequency component of the traveling wave power. Therefore, by extracting this DC component, the maximum value of the fundamental frequency component of the traveling wave power can be detected.

The direct current component (A * B / 2) * cos (α−β) indicating the fundamental frequency component of the traveling wave power has a phase difference α-β of 0 and mπ (m is 1) between the reference high frequency signal and the traveling wave detection signal. When the phase difference α-β is nπ / 2 (n is an odd number equal to or greater than 1), the maximum value is obtained. Therefore, by adjusting the phase difference between the reference high-frequency signal and the traveling wave detection signal to a value other than nπ / 2, the direct current component (A * B / 2) cos (α included in the output of the first multiplier 11 is obtained. The value of -β) can be set to a non-zero value, and the fundamental frequency component of the traveling wave power can be detected by extracting this DC component. In addition, by adjusting the phase difference between the reference high frequency signal and the traveling wave detection signal to 0 or mπ and taking the absolute value of the extracted DC component A * B / 2, the fundamental frequency component of the traveling wave power can be maximized. Can be detected. In the present embodiment, the phase correction unit 12 corrects the phase of the traveling wave detection signal to adjust α = β, and the direct current component A * B / proportional to the maximum value B of the fundamental frequency component of the traveling wave power. Try to get 2. When α = β, equation (1) is
Asin (ωt−α) * Bsin (ωt−α) = (A * B / 2) [1-cos (2ωt−2α)] (1) ′
It becomes.

  In the present embodiment, the output of the first multiplication unit 11 is supplied to the first signal generation unit 13 and passed through a low-pass filter, thereby extracting the DC component A * B / 2 of the expression (1) ′ and proceeding A first analog signal having a level corresponding to the level of the fundamental frequency component of the wave power is obtained, and the first analog signal is used as a signal having a level corresponding to the level of the fundamental frequency component of the traveling wave power. As the low-pass filter constituting the first signal generation unit 13, for example, a low-pass filter having a frequency characteristic indicated by a broken line in FIG. Even if a spurious frequency component is mixed in the traveling wave detection signal, the spurious frequency component does not usually appear in the vicinity of the direct current component (A * B / 2), so that the direct current component can be easily extracted by the low-pass filter. be able to.

  The first analog signal S1 output from the first signal generation unit 13 comprising a low-pass filter is input to the first A / D conversion unit 14, and the first A / D conversion unit 14 outputs the first analog signal S1. Is converted into a first digital value D1 (digital value indicating the maximum value of the fundamental frequency component of traveling wave power) and input to the digital arithmetic processing unit 1. Since the analog signal converted by the first A / D converter 14 is a DC signal, the waveform of the high-frequency power can be obtained even if hardware having a low conversion speed is used as the hardware constituting the first A / D converter 14. The conversion data can be obtained at a sufficient speed as necessary for the output control and the protection control in the case of a pulse-modulated waveform without delay. Therefore, the fundamental frequency component of the traveling wave power can be detected at high speed without imposing a heavy burden on the hardware, and it is sufficient for control when the waveform of the high frequency power is converted to a pulse-modulated waveform. Can respond.

  In this embodiment, the reflected wave detection signal Sr is input to a bandpass filter (BPF) 16 formed of an analog filter, and unnecessary spurious frequency components that are not targeted for detection are removed from the reflected wave detection signal Sr. A processing target reflected wave detection signal Sr ′ including a frequency component and a spurious frequency component to be detected (all detection target spurious frequency components) is generated, and this processing target reflected wave detection signal Sr ′ is combined with the reference high frequency signal Sh2. Input to the second multiplier 15.

The band pal filter 16 has a frequency characteristic as indicated by a broken line in FIG. 5 and passes both the fundamental frequency component included in the reflected wave detection signal and all spurious frequency components to be detected. Use a broadband one. For example, when the fundamental frequency of the high-frequency power is 50 MHz and the spurious frequency component to be detected exists in the frequency band of ± 30 MHz, the filter shown in FIG. 5 passes the frequency component of 20 MHz to 80 MHz. A bandpass filter that can be used is used. For example, when the spurious frequencies to be detected are also 2 MHz and 12 MHz, the band of the bandpass filter 16 is set to 1 MHz to 90 MHz or more. This is to detect main spurious frequencies such as 50 MHz ± 2 MHz, 4 MHz, 6 MHz, 12 MHz, 24 MHz, and 36 MHz in addition to 2 MHz, 12 MHz, and 50 MHz. Furthermore, when it is desired to detect the second harmonic component (100 MHz) as a spurious frequency component when the fundamental frequency of the high frequency power is 50 MHz, a band having a frequency band capable of passing 100 MHz is used as the band pass filter 16. Use a path filter.

  The second multiplication unit 15 multiplies the reference high frequency signal Sh2 by the fundamental frequency component of the reflected wave power included in the processing target reflected wave detection signal Sr 'and each spurious frequency component to be detected. By multiplying the reference high frequency signal by the fundamental frequency component of the reflected wave power, a DC component at a level proportional to the maximum amplitude of the fundamental frequency component of the reflected wave power and a frequency component twice the fundamental frequency are obtained. Further, by multiplying each spurious frequency component by the reference high frequency signal, each spurious frequency component has a difference frequency conversion component having a difference frequency between each spurious frequency and the reference high frequency signal Sh2, and each spurious frequency and the reference high frequency. The frequency is converted into a sum frequency conversion component having a frequency summed with the frequency of the signal Sh2. Therefore, the output signal of the second multiplier 15 includes a DC component proportional to the maximum amplitude of the fundamental frequency component of the reflected wave power, a frequency component twice the fundamental frequency, a difference frequency conversion component, and a sum frequency conversion component. Consists of exchanges including

  To detect the level of all detection target spurious frequency components superimposed on the reflected wave power, either the difference frequency conversion component or the sum frequency conversion component is detected from the frequency converted total detection target spurious frequency components. However, in configuring the filter used for detection, it is more advantageous to detect the difference frequency conversion component existing in the low frequency band. Therefore, in the present embodiment, all the detection target spurious frequency components superimposed on the reflected wave power by extracting the difference frequency conversion component from all the detection target spurious frequency components frequency-converted by the second multiplication unit 15. Detect the level.

  Therefore, in this embodiment, by supplying the output of the second multiplier 15 to the bandpass filter, the output signal of the second multiplier 15 includes a direct current component and a frequency component twice the fundamental frequency. A frequency component included in the set high frequency side set frequency band is removed, and a detection signal having a level corresponding to the level of all detection target spurious frequency components superimposed on the reflected wave power is extracted. In this case, depending on the spurious frequency component superimposed on the reflected wave power, a part of the sum frequency conversion component frequency-converted by the second multiplication unit may be included in the band that the bandpass filter passes. However, since most of the sum frequency conversion component is usually included in a frequency band higher than twice the fundamental frequency, even if the level of all spurious frequency components to be detected is detected by the above method, a large error will occur. Does not occur.

  In the present embodiment, the output signal of the second multiplication unit 15 is input to the second signal generation unit 17 including a band-pass filter composed of an analog filter and a detector that detects the output level of the band-pass filter. Is done. In this case, it is preferable to use a square detector with high accuracy as the detector. The band-pass filter provided in the second signal generation unit 17 has a frequency characteristic as shown by a wavy line in FIG. 6 and has a DC component (0 Hz) and a frequency component that is twice the fundamental frequency of the high-frequency power. What prevents passage of frequency components included in the high frequency set frequency band set so as to be included is used. When the bandpass filter 16 has the above-described characteristics, a bandpass filter having the characteristics shown in FIG. 6 is used, for example, having a band of 0.1 MHz to 80 MHz. The second signal generation unit 17 detects a signal obtained by removing a DC component and a high frequency band including a frequency component twice as high as the fundamental frequency of the high frequency power from the output of the second multiplication unit. A DC second analog signal S2 indicating the level (instantaneous value) of all spurious frequency components of interest is output. In the present embodiment, the second analog signal S2 is used as a detection signal having a level corresponding to the level of the spurious frequency component to be detected among the spurious frequency components superimposed on the reflected wave power. The second analog signal S2 is input to the digital arithmetic processing unit 1 through the second A / D conversion unit 18. The second A / D converter 18 converts the level of the second analog signal S2 into a second digital value D2 and inputs it to the digital arithmetic processor 1.

  The second analog signal S2 is a DC signal indicating the level (instantaneous value) of all detection target spurious frequency components, and the second digital value D2 is a digital signal indicating the level (instantaneous value) of all detection target spurious frequency components. Value. Since the analog signal converted by the second A / D conversion unit 18 is also a DC signal, even if hardware having a low conversion speed is used as the hardware constituting the second A / D conversion unit 18, it is necessary for processing. Conversion data can be obtained at a sufficient speed.

  The processing target reflected wave detection signal Sr ′ output from the bandpass filter 16 is input to a third analog signal generation unit 19 including a square detector and a high cut filter (HCF), and the third analog signal generation unit 19 is input. The third analog signal S3 obtained by the above is input to the digital arithmetic processing unit 1 through the third A / D conversion unit 20.

  The third analog signal generation unit 19 square-detects the processing target reflected wave detection signal including the fundamental frequency component and all the spurious frequency components to be detected (all detection target spurious frequency components), and then uses a high cut filter. The frequency component included in the high frequency band including the frequency twice as high as the fundamental frequency component is removed, and the fundamental frequency component and all the detection target spurious frequency components included in the processing target reflected wave detection signal Sr ′ are included. A DC third analog signal having a level corresponding to the level (instantaneous value) of all reflected wave power components to be detected is output. The third A / D converter 20 converts the level of the third analog signal S3 into a third digital value D3 and inputs it to the digital arithmetic processor 1. The high cut filter can be constituted by a capacitor connected between the output terminal of the detector and the ground.

  The third analog signal S3 is a DC signal indicating the instantaneous value of the reflected wave power of all the detection targets including both the fundamental frequency component and the spurious frequency component, and the third digital value D3 is the total of the reflected wave power of all the detection targets. It is a digital value indicating an instantaneous value. Since the analog signal converted by the third A / D conversion unit 20 is also a direct current signal, even if hardware having a low conversion speed is used as the hardware constituting the third A / D conversion unit 20, it is necessary for processing. Conversion data can be obtained at a sufficient speed.

  The reference high-frequency signal Sh2 output from the duplexer 5 is also input to a reference high-frequency signal level detection unit 21 comprising a square detector, and the output of the reference high-frequency signal level detection unit 21 is digitally processed through the A / D conversion unit 22. It is input to part 1. In the present embodiment, a capacitor is connected between the output terminal of the level detection unit 21 and the ground, and this capacitor converts the frequency component that is twice the fundamental frequency output from the level detection unit 21 together with the DC component into A / D conversion. This constitutes a high cut filter that blocks the input to the unit 22.

  As described above, when the first digital value D1 to the third digital value D3 are obtained, the level of the fundamental frequency component of the traveling wave power can be known from the first digital value and reflected from the second digital value. Among the spurious frequency components included in the wave power, the level of all spurious frequency components to be detected can be known. Further, the level of the reflected wave power of all detection targets including both the fundamental frequency component and all the spurious frequency components to be detected can be detected from the third digital value, and the second digital value can be detected from the third digital value. The fundamental frequency component of the reflected wave power can be detected from the value obtained by subtraction.

  The digital arithmetic processing unit 1 causes the CPU to execute a predetermined program so that a digital output control signal is maintained so as to keep the control target power component obtained from the first digital value D1 to the third digital value D3 at a set value. DL is output, and when the monitored power component obtained from the first digital value D1 to the third digital value D3 exceeds the limit value, the digital power is output so that the monitored power component is reduced below the limit value. A function realizing means for outputting the protection control signal Dp is configured.

  The digital arithmetic processing unit 1 also causes the CPU to execute a predetermined program, thereby giving an amplitude command to the high frequency signal generating unit 4 so as to keep the level of the high frequency detection signal detected by the level detection unit 21 constant. The generator is configured.

  In this embodiment, the control target power component is a fundamental frequency component of traveling wave power obtained from the first digital value D1, and a reflected wave power obtained by subtracting the second digital value D2 from the third digital value D3. The active power obtained by subtracting the level of the fundamental frequency component from the fundamental frequency component level of the traveling wave power obtained from the first digital value, and the total reflected wave power level obtained from the third digital value D3 Is one of the active powers obtained by subtracting from the fundamental frequency component of the traveling wave power.

  In addition, the monitoring target power component in this embodiment is the total value of the fundamental frequency component value of the traveling wave power and the fundamental frequency component value of the reflected wave power, or the fundamental frequency component value of the traveling wave power and the total reflected wave power. It is a total value with the value of.

  The digital arithmetic processing unit 1 outputs an output control signal DL so as to keep the control target power component at a set value. The output control signal DL output from the digital arithmetic processing unit 1 is converted into an analog level control signal SL by the D / A conversion unit 23 and given to the level adjustment unit 602. In order to cope with the case where the output control is performed at a high speed and the high frequency power of the pulse waveform is supplied to the load, the D / A converter 23 receives parallel data instead of serial data. It is preferable to use one. The level adjustment unit 602 adjusts the level of the high-frequency signal Sh1 of a constant level given from the high-frequency signal generation unit 4 through the duplexer 5 to the level indicated by the output control signal SL, and the level is adjusted. The signal is supplied to the amplifier circuit 601. As a result, the output level of the amplifier circuit 601 is adjusted to match the set value.

  When the monitored power component exceeds the limit value, the digital arithmetic processing unit 1 also outputs the protection control signal Dp until the monitored power component falls below the limit value. The protection control signal Dp is converted into an analog protection control signal Sp by the D / A conversion unit 24 and given to the protection control unit 603. In order to protect the semiconductor amplifying element accurately even when the protection control is performed at a high speed and high frequency power having a pulse waveform is supplied to the load, the D / A conversion unit 24 has a serial connection. It is preferable to use data to which parallel data is input instead of data. The protection control unit 603 reduces the gain of the amplifier circuit 601 or reduces the power supply voltage of the amplifier circuit 601 while the protection control signal Sp is being applied, so that the semiconductor amplifier elements constituting the amplifier circuit 601 Perform protection control to prevent damage or deterioration.

  When the digital arithmetic processing unit 1 performs arithmetic processing for outputting the output control signal DL so as to keep the control target power component at the set value, the traveling wave is generated from the first to third digital values D1 to D3. The power value of the fundamental frequency component of the power or the fundamental frequency component of the reflected wave power may be actually obtained, and the output control signal may be generated so as to keep the obtained power value at the set value, which corresponds to the power value. The output control signal may be generated so as to keep the digital value at the set value. For example, when performing control to keep the fundamental frequency component of traveling wave power at a set value, the power value of the fundamental frequency component of traveling wave power is calculated from the first digital value, and the calculated power value is set to the set value. The output control signal may be generated so as to be maintained, or the output control signal may be generated so as to maintain the first digital value itself at a set value. When performing control to maintain the active power obtained by subtracting the fundamental frequency component of the reflected wave power from the fundamental frequency component of the traveling wave power at the set value, the fundamental frequency component of the traveling wave power is calculated from the first digital value D1. Then, the fundamental frequency component of the reflected wave power is calculated from the value obtained by subtracting the second digital value D2 from the third digital value D3, and an output control signal is generated so as to keep the active power obtained therefrom at the set value. Alternatively, the output control signal may be generated so that the value of D1− (D3−D2) itself is kept at the set value. The same applies to the signal processing when the protection control for suppressing the monitored power component to the limit value or less is performed.

  When the first digital value D1 to the third digital value D3 change drastically, if the arithmetic processing is performed using the first digital value D1 to the third digital value D3 as they are, the control becomes unstable. Since there is a fear, the digital arithmetic processing unit 1 performs arithmetic processing after performing averaging processing such as moving average on these digital values. The first digital value D1 corresponds to the maximum value of the fundamental frequency component of traveling wave power, the second digital value D2 corresponds to the instantaneous value of all spurious frequency components to be detected, and the third digital value D3 Although this corresponds to the instantaneous value of the reflected wave power component to be detected, the digital arithmetic processing unit 1 averages all of these digital values, so that the fundamental frequency component of the traveling wave power, the spurious frequency component to be detected, and the total frequency are detected. All the reflected wave power components to be detected are treated as average values. Since a delay occurs in the process of averaging the digital values D1 to D3, and this delay may affect the responsiveness of the output control and protection control, the number of processes when the averaging process is performed depends on the output control. In addition, the number of delays that occur in the protection control is set to the number of times that can be kept within a range that does not cause trouble.

  In the present embodiment, a first multiplier 11, a phase corrector 12, a first signal generator 13, a first A / D converter 14, a second multiplier 15, and a bandpass filter 16, second signal generation unit 17, second A / D conversion unit 18, third signal generation unit 19, and third A / D conversion unit 20, A power component detection unit configured to detect the level of all detection target spurious frequency components (power) included in the reflected wave and the level of total reflected wave power is configured.

  FIG. 3 is a block diagram showing various function realizing means configured by the digital arithmetic processing unit 1 together with the configuration of each unit configured by hardware in the present embodiment. In FIG. 3, reference numeral 30 denotes a power component detection unit. As described above, the reference high-frequency signal Sh2, the traveling wave detection signal Sf, and the reflected wave detection signal Sr are input, and the level of the fundamental frequency component of the traveling wave power is set. A first digital value D1 indicating a second digital value D2 indicating the level of the total spurious frequency component included in the reflected wave power, and a total reflected wave power including both the fundamental frequency component and the spurious frequency component. A third digital value D3 indicating the level is output.

  The digital arithmetic processing unit 1 includes a control target power calculation unit 31, a monitoring target power calculation unit 32, a level control signal generation unit 33, an output level setting unit 34, a protection control signal generation unit 35, and a limit value setting unit. 36, an amplitude command generating unit 37, an amplitude setting unit 38, and a frequency command generating unit 39 are configured.

  The illustrated control target power calculation unit 31 is a power obtained by subtracting the fundamental frequency component of the reflected wave power from the fundamental frequency component of the traveling wave power and the fundamental frequency component of the traveling wave power in accordance with the external command 41 given through the interface 3. One of the second active powers, which is the power obtained by subtracting all the detection target reflected wave power components from the fundamental frequency component of certain first active power and traveling wave power, is calculated as the control target power. Here, the fundamental frequency component of the traveling wave power is obtained from the first digital value D1, and the first active power component is obtained from a value obtained by subtracting the second digital value D2 from the third digital value D3. This is obtained by subtracting the fundamental frequency component of the reflected wave power from the fundamental frequency component of the traveling wave power obtained from the first digital value D1. The second active power component is obtained by subtracting the total detection target reflected wave power component given by the third digital value D3 from the fundamental frequency component of the traveling wave power obtained from the first digital value D1.

  The control target power calculated by the control target power component calculation unit 31 is given to the level control signal generation unit 33 together with the set value of the output level of the amplifier circuit set by the output level setting unit 34. The level control signal generator 33 outputs an output control signal DL that instructs to increase the level of the high-frequency signal input to the amplifier circuit 601 when the calculated level of control target power is lower than the set value. When the calculated level of power to be controlled is higher than a set value, an output control signal DL is output that instructs to reduce the level of the high-frequency signal input to the amplifier circuit 601. As a result, the power amplifying unit is controlled so as to keep the control target power component output from the power amplifying unit at the set value.

  Further, the monitoring target power component calculation unit 32 adds the level of the fundamental frequency component of the traveling wave power and the level of the fundamental frequency component of the reflected wave power in accordance with the external command 42 given through the interface 3. Or the second total value obtained by adding the level of the fundamental frequency component of the traveling wave power and the level of the reflected wave power component of all detection targets is calculated as the monitoring target power component.

  Here, the first total value is a traveling wave in which the level of the fundamental frequency component of the reflected wave power obtained by subtracting the second digital value D2 from the third digital value D3 is obtained from the first digital value D1. It can be obtained by adding to the level of the fundamental frequency component of power. Further, the second total value is obtained by adding the level of the fundamental frequency component of the traveling wave power obtained from the first digital D1 and the level of the reflected wave power component of all the detection objects obtained from the third digital value D3. Required.

  The monitoring target power component calculated by the monitoring target power component calculation unit 32 is given to the protection control signal generation unit 35 together with the limit value set by the limit value setting unit 36. The protection control signal generator 35 outputs a protection control signal Dp that indicates the amount of suppression of the output of the amplifier circuit 601 when the calculated monitored power component exceeds the limit value, and the calculated monitored power When the component falls below the limit value, the output of the protection control signal Dp is stopped. Thereby, the output of the power amplifying unit is controlled so that the monitored power component does not exceed the limit value, and the semiconductor amplifying element constituting the amplifying circuit is prevented from being damaged or deteriorated.

  In the above embodiment, the high frequency signal generator 4 may generate a continuous sinusoidal high frequency signal as shown in FIG. 7A, or a sinusoidal high frequency signal as shown in FIG. 7B. May be modulated to generate a high-frequency signal having a pulse waveform (intermittent waveform).

  As in the above embodiment, a part of the high-frequency signal output from the high-frequency signal generator 4 is demultiplexed to obtain a reference high-frequency signal having the same waveform and frequency as the high-frequency signal, and directly using this reference high-frequency signal. If the fundamental frequency component of the traveling wave power is detected by performing detection, there is no need to provide a local signal generating unit in addition to the high frequency signal generating unit 4 as in the case of frequency conversion. The configuration can be simplified. Since only the high-frequency signal generator 4 needs to be provided as the signal generator, it is necessary to take measures to prevent interference between the signal generators and to take advanced noise countermeasures and to operate the signal generator synchronously. The circuit configuration can be simplified and manufacturing can be facilitated.

  Further, as in the above embodiment, the processing target reflected wave detection signal Sr ′ and the reference high frequency signal Sh2 obtained by removing unnecessary spurious frequency components (spurious frequency components not to be detected) from the reflected wave detection signal Sr. To detect a signal obtained by removing the frequency component included in the set frequency band on the high frequency side set so as to include the DC component and the frequency component twice the fundamental frequency from the signal obtained by multiplying Thus, the second analog signal indicating the level of all the detection target spurious frequency components is obtained, and the second analog signal level is converted into a digital value to thereby obtain the second level indicating the level of all the detection target spurious frequency components. If the digital value is obtained, the level of all spurious frequency components to be detected can be detected with high accuracy, and the spurious frequency component mode can be detected. Nita can be made possible.

  Further, as in the above-described embodiment, by detecting the reflected wave detection signal, it corresponds to the level of the reflected wave power component of all detection targets including both the fundamental frequency component and all the spurious frequency components to be detected. After obtaining a third analog signal having a level, the level of all reflected wave power components including the fundamental frequency component and all the detected spurious frequency components is converted by digitally converting the third analog signal. A fundamental frequency component of reflected wave power is detected by subtracting a second digital value indicating all spurious frequency components to be examined from the third digital value. Then, the fundamental frequency component of the reflected wave power can be accurately detected without using a narrow band filter. Therefore, it is possible to accurately detect the fundamental frequency components of the traveling wave power and the reflected wave power without using a digital filter that performs complex arithmetic processing, and to maintain the active power within the set range, and the traveling wave power and the reflected wave Protection control for controlling the power amplifying unit so that the total value with the power does not exceed the limit value can be performed with high accuracy without imposing a heavy burden on the hardware.

  Further, as in the above-described embodiment, the first analog signal to the third analog signal composed of a DC signal are A / D converted, and the first digital value indicating the fundamental frequency component of the traveling wave power and all detections are detected. A second digital value indicating the target spurious frequency component and a third digital value indicating the total detection target reflected power component are obtained, and the control target power component and the monitoring target power component are detected from these digital values. Then, since it does not require high-speed A / D conversion when detecting the control target power component and the monitoring target power component, the control target power component and the monitoring target power component can be detected at high speed without placing a heavy burden on the hardware. Thus, output control and protection control can be performed with a high response speed. Accordingly, the output control and the protection control when the high frequency power having a continuous sinusoidal waveform as shown in FIG. 7A is supplied to the load can be performed accurately and stably. As shown in Fig. 3, even when the sinusoidal high-frequency power supplied to the load is modulated into a pulse waveform to create an intermittent waveform, output control is performed without placing a heavy burden on hardware and without causing waveform distortion. And protection control can be performed accurately and stably.

  By configuring as in the above embodiment, it is possible to improve control responsiveness without increasing the speed of each multiplication unit, each AD conversion unit, and digital arithmetic processing unit. The high frequency power supply device with high control responsiveness can be obtained without increasing the cost by configuring the hardware using.

  Further, as in the above embodiment, the reference high-frequency signal level detection unit 21 for detecting the level of the reference high-frequency signal Sh2 is provided, and the level of the reference high-frequency signal detected by the reference high-frequency signal level detection unit is kept constant. When the high frequency signal control loop for controlling the high frequency signal generator 4 is configured, the levels of the high frequency signal and the reference high frequency signal can be kept constant, so that the control can be performed stably.

  Further, as in the above embodiment, the fundamental frequency component of the traveling wave power detected from the first digital value D1 and the value obtained by subtracting the second digital value D2 from the third digital value D3 in accordance with an external command. One of the active power component detected from the value obtained by subtracting the first digital value D1 and the active power component indicated by the value obtained by subtracting the third digital value D3 from the first digital value D1 is the control target power component. Since the control target power component can be easily changed, it is possible to easily configure a high-frequency power supply device that meets the specifications required by the user.

  Further, as in the above embodiment, the fundamental frequency component of the traveling wave power obtained from the first digital value D1 and the value obtained by subtracting the second digital value D2 from the third digital value D3 according to the external command. Or the total value of the fundamental frequency component of the reflected wave power obtained from the above, or the total reflected wave power of the detection object obtained from the level of the fundamental frequency component of the traveling wave power obtained from the first digital value D1 and the third digital value D3. When configured to calculate the total value with the component level as the monitoring target power component, the monitoring target power component can be easily changed, so a high-frequency power supply device that meets the specifications required by the user can be provided. It can be easily configured.

  In the above embodiment, the phase correction unit 12 is provided so as to correct the phase of the traveling wave detection signal Sf. However, the phase correction unit 12 sets the phase difference between the reference high frequency signal and the traveling wave detection signal to a value other than nπ / 2. Therefore, as shown in FIG. 2, the phase correction unit 12 may be provided to correct the phase of the reference high-frequency signal.

  In the above embodiment, the reflected wave detection signal Sr is input to the band-pass filter 16 in order to remove unnecessary spurious frequency components that are not to be detected from the reflected wave detection signal Sr. Sr 'is obtained, but when all spurious frequency components included in the reflected wave power are to be detected, the band pal filter 16 is omitted and the reflected wave detection obtained from the high frequency detector 8 is detected. The signal Sr itself is used as a processing target reflected wave detection signal Sr ′.

  In the above embodiment, the total value of the fundamental frequency component of the traveling wave power and the fundamental frequency component of the reflected wave power, or both the fundamental frequency component of the traveling wave power, the fundamental frequency component, and the spurious frequency component to be detected. Although the protection control is performed using the total value of all the reflected wave power components to be detected including the monitoring target power component, the present invention monitors only the fundamental frequency component of the reflected wave power or the reflected wave power component to be detected. The case where protection control is performed as a target power component is also included.

  In the above embodiment, the second signal generation unit 17 is configured by a band pal filter and a detector (preferably a square detector) for detecting the output of the band pass filter, and the second analog signal is converted into a DC signal. However, the detector may be omitted, and the second signal generation unit 17 may be configured only by the band pal filter. In this case, since the second analog signal is an AC signal, the hardware configuring the second A / D converter 18 is necessary for performing output control and protection control without delay. Although it is necessary to use an AC signal that can be A / D converted at a speed necessary to obtain a detection speed, in the present invention, the first A / D converter and the third A / D converter are provided. Since low-cost hardware can be used for each component, even if the cost of the second A / D converter 18 is slightly increased, the overall increase in cost can be suppressed.

DESCRIPTION OF SYMBOLS 1 Digital arithmetic processing part 4 High frequency signal generation part 5 Splitter 6 Power amplification part 601 Amplification circuit 602 Level adjustment part 603 Protection control part 8 High frequency detection part 9 Load 11 1st multiplication part 12 Phase correction part 13 1st signal Generation unit 14 First A / D conversion unit 15 Second multiplication unit 16 Band pass filter 17 Second signal generation unit 18 Second A / D conversion unit 19 Third signal generation unit 20 Third A / D converter 21 Reference high-frequency signal level detector 22 A / D converter

Claims (6)

A high-frequency signal generating unit that generates a high-frequency signal having a sine waveform, an amplification circuit that amplifies the high-frequency signal and outputs high-frequency power, a level adjustment unit that adjusts an output level of the amplification circuit according to an output control signal, and protection control A power amplifying unit having a protection control unit that suppresses an output of the amplifier circuit according to a signal; and a traveling wave detection signal and a reflected wave detection signal by detecting traveling wave power and reflected wave power from the output of the power amplifying unit. An output control signal is provided to the power amplifier so as to keep a control target power component detected from the traveling wave detection signal and the reflected wave detection signal at a set value, and the traveling wave detection signal and A high-frequency power supply device comprising a control unit that gives the protection control signal to the power amplification unit so as to keep the monitored power component detected from the reflected wave detection signal below a limit value,
The controller is
A reference high-frequency signal generation unit that demultiplexes a part of the high-frequency signal input from the high-frequency signal generation unit to the level adjustment unit and obtains a reference high-frequency signal having the same waveform and frequency as the high-frequency power supplied to the load;
A phase correction unit that corrects the phase difference between the traveling wave detection signal and the reference high-frequency signal to a value other than nπ / 2 (n is an odd number equal to or greater than 1);
A first multiplier that multiplies the traveling wave detection signal whose phase difference is corrected by the phase correction unit and a reference high-frequency signal;
All frequency components other than the fundamental frequency component of the high-frequency power are set as spurious frequency components, and the reflected wave detection signal or the signal obtained by removing the spurious frequency component not to be detected from the reflected wave detection signal is detected as a processing target reflected wave. A second multiplication unit that multiplies the reflected wave detection signal to be processed and the reference high-frequency signal as a signal;
A first signal generator that extracts a direct current component from the output of the first multiplier and obtains a first analog signal having a level corresponding to the level of the fundamental frequency component of the traveling wave power;
Of the spurious frequency components, the spurious frequency components to be detected are all spurious frequency components to be detected, and are set to include a frequency component that is twice the direct current component and the fundamental frequency from the output of the second multiplier. It was to remove the frequency components contained in the high frequency side set frequency band, first to obtain a second analog signal having a level corresponding to the level of the total detected spurious frequency components contained in the processing target reflected wave detection signal Two signal generators;
The detection target reflected wave detection signal is detected and has a level corresponding to the level of the total detection target reflected wave power component including the fundamental frequency component and the all detection target spurious frequency component included in the processing target reflected wave detection signal. A third signal generator for obtaining a third analog signal;
First to third A / D converters for converting the levels of the first analog signal to the third analog signal to first digital values to third digital values, respectively;
The control target power component and the monitoring target power component are obtained from the first digital value to the third digital value, and the output control signal is output so as to keep the obtained control target power component at a set value. A digital arithmetic processing unit that outputs the protection control signal so as to suppress the monitoring target power component below the limit value when the monitoring target power component exceeds the limit value;
With
The digital arithmetic processing unit includes a fundamental frequency component of traveling wave power obtained from the first digital value, and a fundamental frequency component of reflected wave power obtained from a value obtained by subtracting a second digital value from the third digital value. Is obtained by subtracting the active power component obtained by subtracting from the fundamental frequency component of the traveling wave power obtained from the first digital value, or the total detection target reflected wave power component obtained from the third digital value. The active power component obtained by subtracting from the fundamental frequency component of the traveling wave power obtained from the digital value is obtained as the control target power component, and the fundamental frequency component of the traveling wave power obtained from the first digital value and the first A total value of the fundamental frequency component of the reflected wave power obtained from a value obtained by subtracting the second digital value from the digital value of 3, the first data The total value of the fundamental frequency component of the traveling wave power obtained from the tall value and the reflected wave power component of all the detection objects obtained from the third digital value, only the fundamental frequency component of the reflected wave power, or the reflection of all the detection objects It is configured to obtain only the wave power component as the monitoring target power component,
A high frequency power supply device characterized by.   The second signal generation unit removes a frequency component included in a high frequency side set frequency band set so as to include a DC component and a frequency component twice the fundamental frequency from the output of the second multiplication unit. And a DC second analog signal having a level corresponding to the level of all spurious frequency components included in the reflected wave detection signal to be processed is obtained. Item 4. The high frequency power supply device according to Item 1. The digital arithmetic processing unit is a fundamental frequency component of traveling wave power obtained from the first digital value, a value obtained by subtracting a value obtained by subtracting a second digital value from the third digital value from the first digital value. The active power component calculated from the first digital value and the active power component calculated from the value obtained by subtracting the third digital value from the first digital value are calculated as the control target power component according to an external command. The high frequency power supply device according to claim 1, wherein the high frequency power supply device is provided. The digital arithmetic processing unit includes a fundamental frequency component of traveling wave power obtained from the first digital value and a fundamental frequency component of reflected wave power obtained from a value obtained by subtracting a second digital value from the third digital value. Or the total value of the fundamental wave component of traveling wave power obtained from the first digital value and the reflected wave power component of all detection objects obtained from the third digital value as the monitoring object power component The high-frequency power supply device according to claim 1, wherein the high-frequency power supply device is configured to perform an operation according to an external command. A reference high-frequency signal level detection unit for detecting a level of the reference high-frequency signal;
2. A high-frequency signal control loop configured to control the high-frequency signal generation unit so as to keep a level of the reference high-frequency signal detected by the reference high-frequency signal level detection unit constant. 5. The high frequency power supply device according to 3 or 4 . 6. The high frequency power supply device according to claim 1, wherein the high frequency signal generator is configured to modulate a sine waveform high frequency signal into a pulse waveform and output the pulse waveform .

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