JP6798306B2 - Phase adjuster, phase detector, motor drive, motor drive system, image forming device, and transfer device - Google Patents

Description

The present invention relates to a phase adjusting device that has a phase difference from each other and adjusts the phase of an intersection between a plurality of periodic signals that change periodically and continuously in the same period. The present invention also relates to a phase detection device, a motor drive device, a motor drive system, an image forming device, and a transfer device provided with such a phase adjusting device.

Some electronic circuits have phase differences with each other and handle multiple periodic signals that change periodically and continuously at the same period. For example, as such a periodic signal, there are a plurality of sensor signals obtained from a plurality of sensors provided in the motor in order to detect the rotation angle of the rotor of the motor. These sensor signals are obtained from a plurality of magnetic sensors provided with a predetermined angle difference around the rotation axis in a motor having a rotor having a predetermined number of magnetic poles, and are caused by the rotation of the rotors. Represents each change in magnetic flux.

For example, Patent Documents 1 to 3 disclose electronic circuits that handle a plurality of periodic signals.

For example, Patent Document 1 describes a motor drive control device that drives a motor by generating a phase information signal based on a plurality of sensor signals having a signal level corresponding to a rotation position of a rotor of a motor having a multi-phase coil. It is disclosed. The motor drive control device generates a first phase information signal indicating the detected phase by comparing a plurality of sensor signals with a plurality of predetermined threshold levels, and the phase detected by comparing the plurality of sensor signals. A second phase information signal indicating is generated. The motor drive control device divides the detected phase contained in the first phase information signal and the second phase information signal into a plurality of predetermined phase sections, and from among the plurality of sensor signals in the predetermined plurality of phase sections. Select one. The motor drive controller detects that the signal level of the selected sensor signal has reached a predetermined threshold level corresponding to a predetermined phase of the rotor.

According to Patent Document 1, the intersection of a plurality of sensor signals and a threshold level is detected, the intersection of a plurality of sensor signals is detected, and a predetermined sensor signal and a rotor selected in each phase interval are detected. Detects the intersection with a predetermined threshold level according to the phase. As a result, phase information that is more subdivided than the interval at which the sensor signal changes is generated.

The phase detection of Patent Document 1 can detect the phase of an accurate intersection and generate accurate phase information if it handles an ideal sensor signal having a phase and a waveform that match the design values. However, the phase and waveform of the actual sensor signal may have an error with respect to the design value. At this time, the phase of the intersection also has an error with respect to the design value, and accurate phase information cannot be generated.

An object of the present invention is to adjust the phase of an intersection between periodic signals so as to reduce the error with the design value even if the phase or waveform of a plurality of input periodic signals has an error with respect to the design value. The purpose is to provide an adjusting device.

According to one aspect of the invention
A phase adjusting device that adjusts the phase of an intersection between a plurality of periodic signals that have a phase difference from each other and change periodically and continuously in the same period.
A signal level detecting means for detecting the signal level at the intersection, and
A signal level adjusting means for adjusting the signal level of at least one periodic signal among the plurality of periodic signals is provided.
In the signal level adjusting means, in each of the plurality of adjustment sections based on the phases of the plurality of periodic signals, the signal level at the intersection of the two periodic signals of the plurality of periodic signals has a difference from the target level. Then, the signal level of one of the two periodic signals is adjusted so as to reduce the difference.

According to the present invention, even if the phases or waveforms of a plurality of input periodic signals have an error with respect to the design value, the phase for adjusting the phase of the intersection between the periodic signals so as to reduce the error with the design value. An adjusting device can be provided.

It is a block diagram which shows the structure of the phase adjustment apparatus 1 which concerns on Embodiment 1 of this invention. It is a circuit diagram which shows the structure of the signal level adjustment circuit 10 of FIG. It is a table which shows the relationship between the input signal and the output signal of the intersection detection circuit 20 of FIG. It is a figure which shows the state which the position of the sensor S2 of FIG. 1 deviated from the design position. FIG. 5 is a waveform diagram showing U-phase, V-phase, and W-phase sensor signals input from sensors S1 to S3 when the sensors S1 to S3 are in the state of FIG. 4 in the phase adjusting device 1 of FIG. FIG. 5 is a waveform diagram showing signals U1, V1 and W1 output from the signal level adjusting circuit 10 when the sensor signal of FIG. 5 is input to the phase adjusting device 1 of FIG. It is a figure which shows the state which the strength of a plurality of magnets of the rotor M1a of the motor M1 of FIG. 1 varies. FIG. 5 is a waveform diagram showing U-phase, V-phase, and W-phase sensor signals input from sensors S1 to S3 when the rotor M1a of the motor M1 is in the state of FIG. 7 in the phase adjusting device 1 of FIG. .. FIG. 5 is a waveform diagram showing signals U1, V1, W1 output from the signal level adjusting circuit 10 when the sensor signal of FIG. 8 is input to the phase adjusting device 1 of FIG. 1, and FIG. 1A is a first time interval. It is a figure which shows the signal U1, V1, W1 in the above, (b) is a figure which shows the signal U1, V1, W1 in the second time section after that. It is a block diagram which shows the structure of the phase adjustment apparatus 1A which concerns on the modification of Embodiment 1 of this invention. It is a table which shows the relationship between the input signal and the output signal of the intersection detection circuit 50 of FIG. It is a block diagram which shows the structure of the phase detection apparatus which concerns on Embodiment 2 of this invention. It is a circuit diagram which shows the structure of the intersection detection circuit 130 of FIG. It is a table which shows the condition which selects the signal U1, V1, W1 by the selection circuit 120 of FIG. It is a table which shows the relationship between the normalized threshold signal level and the corresponding phase used in the intersection detection circuit 130 of FIG. It is a timing chart which shows the 1st operation example of the phase detection apparatus of FIG. It is a timing chart which shows the 2nd operation example of the phase detection apparatus of FIG. It is a block diagram which shows the structure of the phase detection apparatus which concerns on Embodiment 3 of this invention. It is a circuit diagram which shows the structure of the intersection detection circuit 130A of FIG. It is a waveform diagram which shows the threshold value signal level set in the intersection detection circuit 130A of FIG. It is a block diagram which shows the structure of the motor drive system which concerns on Embodiment 4 of this invention. It is a circuit diagram which shows the structure of the motor drive circuit 170 of FIG. It is a timing chart which shows the operation of the motor drive circuit 170 of FIG. It is a block diagram which shows the structure of the motor drive system which concerns on the modification of Embodiment 4 of this invention. It is a figure which shows the structure of the image forming apparatus which concerns on Embodiment 5 of this invention.

Hereinafter, embodiments according to the present invention will be described with reference to the drawings. In each of the following embodiments, the same reference numerals are given to the same components.

Embodiment 1.
FIG. 1 is a block diagram showing a configuration of a phase adjusting device 1 according to a first embodiment of the present invention. The phase adjusting device 1 has a phase difference from each other, and has a plurality of sensors S1 to S3 provided in the motor M1 as U-phase, V-phase, as a plurality of periodic signals that change periodically and continuously at the same period. And W phase sensor signals are acquired respectively. The sensors S1 to S3 are magnetic sensors such as Hall elements, and are provided with a predetermined angle difference around the rotation axis in the motor M1 having rotors having a predetermined number of magnetic poles. Each sensor signal represents a change in magnetic flux due to rotation of the rotor. Each sensor signal is, for example, a sine wave or a cosine wave.

The sensor signal can be used to detect the rotation angle of the rotor of the motor M1, as will be described later in Embodiments 2-4.

As mentioned above, the phase and waveform of the actual sensor signal may have an error with respect to the design value.

Hall elements are usually retrofitted to the motor. When retrofitting a sensor to a motor, if the position of a sensor deviates from the design position, the phase of the corresponding sensor signal will deviate uniformly from the design value throughout its period. As a result, the phase of the intersection of this sensor signal and another sensor signal also deviates from the design value.

The error between the phase of the sensor signal and its design value depends on the accuracy of the sensor mounting. For example, consider a case where a plurality of sensors are arranged on a rotor having a diameter of 20 mm and having six magnetic poles having a mechanical angle of 60 degrees. The mechanical angle of 120 degrees of the motor corresponds to the electrical angle of 360 degrees of the sensor signal. In this case, on the circumference of the rotor, the length of the electric angle of 360 degrees is 20 mm × π / 3 = 20.9 mm, and the length of the electric angle of 1 degree is 58.2 μm. If the sensor can be provided in the motor with an accuracy of 58.2 μm or less, the error between the phase of the sensor signal and its design value can be kept within 1 degree of electrical angle. However, this accuracy is difficult to achieve and inevitably the phase of the sensor signal will include an error of several degrees.

In addition, the strength of a plurality of magnets of the rotor may vary due to variations in magnetism during manufacturing. If the strengths of the plurality of rotor magnets vary, the waveform of each sensor signal deviates from the design waveform in the corresponding angular range within the period as the strength of the magnets increases or decreases. In the angle range in which the waveform of each sensor signal deviates from the design waveform, the phase of each sensor signal, particularly the phase of the intersection between the sensor signals, also deviates from the design value.

If the phase of the intersection has an error with respect to the design value, accurate phase information cannot be generated. In order to solve this problem, the phase adjusting device 1 of FIG. 1 has a design value even if the phase or waveform of the input U-phase, V-phase, and W-phase sensor signals has an error with respect to the design value. Adjust the phase of the intersection between the sensor signals so as to reduce the error with.

The phase adjusting device 1 includes a signal level adjusting circuit 10, an intersection detecting circuit 20, a signal level detecting circuit 30, and a control circuit 40.

The signal level adjusting circuit 10 is a signal level adjusting means for adjusting the signal level of at least one of the input U-phase, V-phase, and W-phase sensor signals. FIG. 2 is a circuit diagram showing the configuration of the signal level adjusting circuit 10 of FIG. The signal level adjusting circuit 10 includes a U-phase signal level adjusting circuit 11, a V-phase signal level adjusting circuit 12, and a W-phase signal level adjusting circuit 13. The U-phase signal level adjustment circuit 11 includes an operational amplifier 11a, a variable voltage source 11b, and resistors R11 to R14. A U-phase sensor signal is input from the U-phase sensor S1 to the U-phase signal level adjustment circuit 11. The variable voltage source 11b applies a variable voltage to the operational amplifier 11a under the control of the control circuit 40. The U-phase signal level adjusting circuit 11 adjusts the signal level of the U-phase sensor signal according to the voltage of the variable voltage source 11b, and outputs the adjusted signal U1. However, depending on the voltage of the variable voltage source 11b, the adjustment amount of the signal level of the U-phase sensor signal becomes zero, and the input U-phase sensor signal is output as it is as the adjusted signal U1. The V-phase signal level adjustment circuit 12 and the W-phase signal level adjustment circuit 13 are also configured in the same manner as the U-phase signal level adjustment circuit 11, and output the adjusted signals V1 and W1, respectively.

The intersection detection circuit 20 is a first intersection detection that detects the phase of the intersection between the U-phase, V-phase, and W-phase sensor signals (that is, signals U1, V1, W1) output from the signal level adjustment circuit 10. It is a means. The intersection detection circuit 20 includes comparators 21 to 23. The comparator 21 detects the phase of the intersection between the signals U1 and V1 by comparing the magnitude of the signals U1 and V1, and outputs a signal UV indicating the phase of the detected intersection. The comparator 22 detects the phase of the intersection between the signals V1 and W1 by comparing the magnitude of the signals V1 and W1, and outputs a signal VW indicating the phase of the detected intersection. The comparator 23 detects the phase of the intersection between the signals W1 and U1 by comparing the magnitude of the signals W1 and U1, and outputs a signal WU indicating the phase of the detected intersection.

FIG. 3 is a table showing the relationship between the input signal and the output signal of the intersection detection circuit 20 of FIG. The signal UV output from the intersection detection circuit 20 has a high value or a low value depending on the magnitude of the signals U1 and V1 input to the intersection detection circuit 20. The rising and falling edges of the signal UV indicate the phase of the intersection of the signals U1 and V1. Similar to the signal UV, the signal VW indicates the phase of the intersection of the signals V1 and W1, and the signal WU indicates the phase of the intersection of the signals W1 and U1.

The signal level detection circuit 30 is a signal level detecting means for detecting the signal level at the intersection between the signals U1, V1 and W1. The signal level detection circuit 30 refers to the signals UV, VW, WU (that is, the phase of the intersection between the signals U1, V1, W1 detected by the intersection detection circuit 20) in order to detect the signal level at the intersection.

The control circuit 40 is a control means for controlling the signal level adjusting circuit 10 based on the signal level at the intersection between the signals U1, V1 and W1. First, the control circuit 40 has a plurality of adjustment sections having boundaries for each period of the U-phase sensor signal in a phase different from the phase at the intersection of the U-phase sensor signal and the other V-phase and W-phase sensor signals. Divide into. Next, the control circuit 40 determines a target level that is a target of the signal level at the intersection of the U-phase sensor signal and the other V-phase and W-phase sensor signals. Next, the control circuit 40 adjusts the signal level of the U-phase sensor signal by the signal level adjustment circuit 10 so as to reduce the difference between the signal level at the intersection and the target level in each of the plurality of adjustment sections. As a result, the control circuit 40 adjusts the phase of the intersection of the U-phase sensor signal and the other V-phase and W-phase sensor signals. The control circuit 40 adjusts the signal levels of the V-phase and W-phase sensor signals as well as the U-phase sensor signals.

The control circuit 40 has a plurality of adjustment sections for each of the U-phase, V-phase, and W-phase sensor signals so that each period of the sensor signal has a boundary at the phase of the intersection between the other two sensor signals. Divide into.

The control circuit 40 is based on the number of magnetic poles of the rotor of the motor M1, the positions of the sensors S1 to S3 in the motor M1, and the maximum and minimum values of the U-phase, V-phase, and W-phase sensor signals. Determine the target level. The number of magnetic poles of the rotor of the motor M1 and the positions of the sensors S1 to S3 in the motor M1 are input to the control circuit 40 via, for example, the input device 2. When the waveforms of the U-phase, V-phase, and W-phase sensor signals are known, the control circuit 40 should have an intersection between the U-phase, V-phase, and W-phase sensor signals based on the above information. Signal level can be estimated. For example, when the waveforms of the U-phase, V-phase, and W-phase sensor signals are sinusoidal and have a phase difference of 120 degrees of electrical angle from each other, the signal levels at their intersections are the maximum and minimum values of the sensor signals. It is presumed to have a value obtained by adding and subtracting 1/2 of the amplitude of the sensor signal to the median value of. The signal level estimated in this way becomes the target level.

The control circuit 40 determines the amount of adjustment of the signal level of the sensor signal for each of the U-phase, V-phase, and W-phase sensor signals, and for each of the plurality of adjustment sections, and stores the adjustment amount internally. Each determined adjustment amount is applied to each sensor signal in each adjustment section. As a result, the signal level adjustment circuit 10 reduces one of the two sensor signals when the signal level at the intersection of the two sensor signals has a difference with respect to the target level in each adjustment section. Adjust the signal level of.

The phase adjusting device 1 outputs signals U1, V1 and W1.

Next, with reference to FIGS. 4 to 6, the adjustment of the signal level of the sensor signal when the position of the sensor deviates from the design position will be described.

FIG. 4 is a diagram showing a state in which the position of the sensor S2 in FIG. 1 deviates from the design position. The motor M1 of FIG. 1 includes a rotor M1a having six magnetic poles P1 to P6 over a mechanical angle of 60 degrees. According to the arrangement of the magnetic poles P1 to P6 as shown in FIG. 4, when the rotor M1a makes one rotation, the magnetic flux detected by each of the sensors S1 to S3 is inverted 6 times. The mechanical angle of 120 degrees of the motor M1 corresponds to an electric angle of 360 degrees of the sensor signal. By design, the sensors S1 to S3 should be arranged with a mechanical angle of 40 degrees to each other and the corresponding sensor signals should have an electrical angle of 120 degrees to each other. However, in the example of FIG. 4, the position of the sensor S2 deviates from the design position over the mechanical angle Err1. Therefore, the sensors S1 and S2 are arranged with each other having a mechanical angle of 40 degrees + Err1, and the corresponding sensor signals have an electrical angle of 120 degrees + Err1'with respect to each other.

FIG. 5 is a waveform diagram showing U-phase, V-phase, and W-phase sensor signals input from sensors S1 to S3 when the sensors S1 to S3 are in the state of FIG. 4 in the phase adjusting device 1 of FIG. Is. Hereinafter, the median value of the maximum value and the minimum value of the sensor signal is referred to as a "common level". According to the arrangement of the sensors S1 to S3 as shown in FIG. 4, the phase (thick solid line) of the V-phase sensor signal deviates from the design phase (broken line) over the electric angle Err1'. The phases of the U-phase and W-phase sensor signals match the design phase.

According to FIG. 5, the intersections uv_t (1), uv_t (2), and uv_t (3) between the U-phase and V-phase sensor signals higher than the common level due to the phase shift of the V-phase sensor signals. The phase and signal level deviate from the design values. Similarly, the phases and signal levels of the intersections vw_t (1), vw_t (2), and vw_t (3) between the V-phase and W-phase sensor signals higher than the common level deviate from the design values. Similarly, the phases and signal levels of the intersections uv_b (1), uv_b (2), and uv_b (3) between the U-phase and V-phase sensor signals lower than the common level deviate from the design values. Similarly, the phases and signal levels of the intersections vw_b (1), vw_b (2), and vw_b (3) between the V-phase and W-phase sensor signals lower than the common level deviate from the design values. On the other hand, the phase and signal levels of the intersections woo_t (1), woo_t (2), woo_t (3), woo_b (1), woo_b (2), and woo_b (3) between the w-phase and U-phase sensor signals are design values. Matches.

In FIG. 5, uv_t_avg indicates the average value of the signal levels of the intersections uv_t (1), uv_t (2), and uv_t (3) between the U-phase and V-phase sensor signals higher than the common level. vw_t_avg indicates the average value of the signal levels of the intersection points vw_t (1), vw_t (2), and vw_t (3) between the V-phase and W-phase sensor signals higher than the common level. woo_t_avg indicates the average value of the signal levels of the intersection points woo_t (1), woo_t (2), and woo_t (3) between the W-phase and U-phase sensor signals higher than the common level. uv_b_avg indicates the average value of the signal levels of the intersections uv_b (1), uv_b (2), and uv_b (3) between the U-phase and V-phase sensor signals lower than the common level. vw_b_avg indicates the average value of the signal levels of the intersection points vw_b (1), vw_b (2), and vw_b (3) between the V-phase and W-phase sensor signals lower than the common level. woo_b_avg indicates the average value of the signal levels of the intersection points woo_b (1), woo_b (2), and woo_b (3) between the W-phase and U-phase sensor signals lower than the common level. t_avg indicates the average value of the signal levels at all intersections between sensor signals higher than the common level. b_avg indicates the average value of the signal levels at all intersections between sensor signals below the common level.

According to FIG. 5, due to the phase deviation of the V-phase sensor signal from the design value, the phase and signal level of the intersection between the U-phase and V-phase sensor signals deviate from the design value, and the V-phase and W-phase The phase and signal level of the intersection between the sensor signals deviates from the design value. According to FIG. 5, since the phase shift of the intersection and the signal level shift of the intersection are linked, it is considered that the phase shift of the intersection can be reduced by correcting the signal level shift of the intersection.

FIG. 6 is a waveform diagram showing signals U1, V1 and W1 output from the signal level adjusting circuit 10 when the sensor signal of FIG. 5 is input to the phase adjusting device 1 of FIG. The signal level adjustment circuit 10 adjusts the signal level of the input V-phase sensor signal (broken line) in each of the plurality of adjustment sections in which each period of the V-phase sensor signal is divided, and the adjusted signal V1 ( (Thick solid line) is output. First, the control circuit 40 divides each period of the V-phase sensor signal into a plurality of adjustment sections B1 to B6 having a boundary at the phase of the intersection between the other U-phase and W-phase sensor signals. Next, the control circuit 40 determines a target level that is a target of the signal level at the intersection of the V-phase sensor signal and the other U-phase and W-phase sensor signals. Next, the control circuit 40 adjusts the signal level of the V-phase sensor signal by the signal level adjustment circuit 10 so as to reduce the difference between the signal level at the intersection and the target level in each of the plurality of adjustment sections B1 to B6. To do. As a result, the control circuit 40 adjusts the phase of the intersection of the V-phase sensor signal and the other U-phase and W-phase sensor signals.

The signal levels of the U-phase and W-phase sensor signals are adjusted in the same manner as the V-phase sensor signals. Each cycle of the U-phase sensor signal is divided into a plurality of adjustment sections A1 to A6, and each cycle of the W-phase sensor signal is divided into a plurality of adjustment sections C1 to C6. However, in the example of FIG. 6, by adjusting the signal level of the V-phase sensor signal, it is not necessary to adjust the signal level of the U-phase and W-phase sensor signals.

When the signal level at the intersection between the two sensor signals deviates from the target level, the control circuit 40 determines which of these two sensor signals should be adjusted for the signal level as follows. .. First, the control circuit 40 identifies the U-phase, V-phase, and W-phase sensor signals by referring to the number of magnetic poles of the rotor of the motor M1 and the positions of the sensors S1 to S3 in the motor M1. When the number of magnetic poles of the rotor of the motor M1 changes, the phase difference between the sensor signals changes. For example, when the sensors are arranged with a mechanical angle of 40 degrees from each other, if the rotor has six magnetic poles, the phase difference between the sensor signals is an electric angle of 120 degrees, and the rotor has 12 degrees. If it has a number of magnetic poles, the phase difference between the sensor signals is an electric angle of 240 degrees. Further, when the positions of the sensors S1 to S3 in the motor M1 change, the order of each phase of the corresponding sensor signal changes from, for example, "W phase-> U phase-> V phase" to "U phase-> V phase-> W phase". To do. The control circuit 40 determines the phase difference between the sensor signals and the order of each phase of the sensor signals based on the number of magnetic poles of the rotor of the motor M1 and the positions of the sensors S1 to S3 in the motor M1. Based on this, the U-phase, V-phase, and W-phase sensor signals are identified. After identifying the U-phase, V-phase, and W-phase sensor signals, the control circuit 40 then arbitrarily determines the sensor signal whose signal level should be adjusted, out of the two sensor signals having intersections in a certain adjustment section. To do. For example, the control circuit 40 identifies a sensor signal that first passes through the common level after the rotor of the motor M1 begins to rotate. The control circuit 40 is then specified to reduce the difference in each adjustment interval when the signal level at the intersection of this identified sensor signal with another sensor signal has a difference with respect to the target level. Adjust the signal level of the sensor signal.

As described above, the target levels are the number of magnetic poles of the rotor of the motor M1, the positions of the sensors S1 to S3 in the motor M1, and the maximum and minimum values of the U-phase, V-phase, and W-phase sensor signals. It may be determined based on. For example, when the waveforms of the U-phase, V-phase, and W-phase sensor signals are sinusoidal and have a phase difference of 120 degrees of electrical angle from each other, the target level is the common level, which is 1/2 of the amplitude of the sensor signal. The added and subtracted signal levels.

Further, the target level may be determined based on the average value of the signal levels detected by the signal level detection circuit 30. The control circuit 40 sets the same signal level among the intersections between the U-phase, V-phase, and W-phase sensor signals based on the number of magnetic poles of the rotor M1a and the positions of the sensors S1 to S3 in the motor M1. A group of one or more intersections including a plurality of predetermined intersections to have is determined. In the example of FIG. 5, the signal levels of the intersections consisting of intersections between sensor signals higher than the common level should coincide with each other, and the signal levels of the intersections consisting of intersections between sensor signals lower than the common level should match each other. Should match. The control circuit 40 is the signal level of the intersection included in the intersection group higher than the common level, and the average value t_avg of the signal level detected by the signal level detection circuit 30 is set to the target level of the intersection group higher than the common level. To determine as. Similarly, the control circuit 40 is the signal level of the intersection included in the intersection group lower than the common level, and the average value b_avg of the signal levels detected by the signal level detection circuit 30 is set to the intersection group lower than the common level. Determined as the target level of.

The control circuit 40 individually calculates the adjustment amount related to a plurality of intersections (for example, vw_t (1), vw_t (2), vw_t (3)) between the same two sensor signals for each adjustment section including each intersection. You may. Further, the control circuit 40 calculates a common adjustment amount (for example, vw_t_avg-t_avg) over a plurality of adjustment sections by using the average value of the signal levels at a plurality of intersections between the same two sensor signals (for example, vw_t_avg). You may.

When the position of a sensor deviates from the design position and the phase of the corresponding sensor signal deviates uniformly from the design value over the entire period, the section where the gradient of the sensor signal is positive and the section where the gradient is negative , The signal level of the sensor signal is adjusted in the opposite direction (increase and decrease).

According to FIGS. 4 to 6, even when the position of a sensor deviates from the design position and the phase of the corresponding sensor signal deviates uniformly from the design value over the entire period, the design value and The phase of the intersection between the sensor signals can be adjusted to reduce the error.

Next, with reference to FIGS. 7 to 9, adjustment of the signal level of the sensor signal when there is a variation in the strength of the plurality of magnets of the rotor will be described.

FIG. 7 is a diagram showing a state in which the strengths of the plurality of magnets of the rotor M1a of the motor M1 of FIG. 1 vary. By design, the rotor M1a of FIG. 7 includes a rotor M1a having six magnetic poles P1 to P6 having a mechanical angle of 60 degrees. However, in the example of FIG. 7, the magnetic flux density in the vicinity of the right magnetic pole P2 is weaker than the design value. As a result, the mechanical angle of the magnetic pole P2 is equivalently reduced to 60 degrees −Err2-Err3, and the mechanical angles of the magnetic poles P1 and P3 adjacent to both sides thereof are increased to 60 degrees + Err2 and 60 degrees Err3. The sensors S1 to S3 of FIG. 7 are arranged with each other having a mechanical angle of 40 degrees, and the corresponding sensor signals have an electric angle of 120 degrees with each other.

FIG. 8 shows U-phase, V-phase, and W-phase sensor signals input from sensors S1 to S3 when the rotor M1a of the motor M1 is in the state of FIG. 7 in the phase adjusting device 1 of FIG. It is a waveform diagram. According to the configuration of FIG. 7, the waveforms (thick solid lines) of the U-phase, V-phase, and W-phase sensor signals are designed in the angle range corresponding to when the magnetic poles P1 to P3 pass in the vicinity of the sensors S1 to S3. It deviates from the above waveform (broken line). In the angle range corresponding to when the magnetic pole P2 passes in the vicinity of the sensors S1 to S3, the amplitudes of the U-phase, V-phase, and W-phase sensor signals decrease. In the angle range corresponding to when the magnetic poles P1 and P3 pass in the vicinity of the sensors S1 to S3, the amplitudes of the U-phase, V-phase, and W-phase sensor signals increase. In the remaining angular range, the waveforms of the U-phase and W-phase sensor signals match the design waveforms. The deformation of the waveforms of the U-phase, V-phase, and W-phase sensor signals appears periodically according to the rotation of the rotor M1a.

According to FIG. 8, among the intersections between the U-phase and V-phase sensor signals higher than the common level due to the waveforms of the U-phase, V-phase, and W-phase sensor signals deviating from the design waveforms, the intersections. The phase and signal level of uv_t (1) and uv_t (2) deviate from the design values. The phase and signal level of the intersection uv_t (3) match the design values. Similarly, among the intersections between the U-phase and V-phase sensor signals lower than the common level, the phase and signal level of the intersection uv_b (1) deviate from the design values. The phases and signal levels of the intersections uv_b (2) and uv_b (3) match the design values. Similar to the intersection between the U-phase and V-phase sensor signals, the intersection between the V-phase and W-phase sensor signals and the intersection between the W-phase and U-phase sensor signals also deviate from the design values.

FIG. 9 is a waveform diagram showing signals U1, V1 and W1 output from the signal level adjusting circuit 10 when the sensor signal of FIG. 8 is input to the phase adjusting device 1 of FIG. FIG. 9A is a diagram showing signals U1, V1, W1 in the first time interval, and FIG. 9B is a diagram showing signals U1, V1, W1 in the subsequent second time interval. The signal level adjustment circuit 10 adjusts and adjusts the signal level of the input sensor signal (broken line) in each of the plurality of adjustment sections in which each period of the U-phase, V-phase, and W-phase sensor signals is divided. The signals U1, V1, W1 (thick solid line) are output. The control circuit 40 operates in the same manner as in the case described with reference to FIGS. 4 to 6. First, the control circuit 40 divides each period of the V-phase sensor signal into a plurality of adjustment sections having a boundary at the phase of the intersection between the other U-phase and W-phase sensor signals. Next, the control circuit 40 determines a target level that is a target of the signal level at the intersection of the V-phase sensor signal and the other U-phase and W-phase sensor signals. Next, the control circuit 40 adjusts the signal level of the V-phase sensor signal by the signal level adjustment circuit 10 so as to reduce the difference between the signal level at the intersection and the target level in each of the plurality of adjustment sections. As a result, the control circuit 40 adjusts the phase of the intersection of the V-phase sensor signal and the other U-phase and W-phase sensor signals. The control circuit 40 adjusts the signal levels of the U-phase and W-phase sensor signals as well as the V-phase sensor signals.

In the examples of FIGS. 7-9, the target level is determined in the same manner as in FIGS. 4-6.

The control circuit 40 individually calculates the adjustment amount related to a plurality of intersections (for example, uv_t (1), uv_t (2), uv_t (3)) between the same two sensor signals for each adjustment section including each intersection. You may. Further, the control circuit 40 calculates a common adjustment amount (for example, uv_t_avg-t_avg) over a plurality of adjustment sections by using the average value of the signal levels at a plurality of intersections between the same two sensor signals (for example, uv_t_avg). You may.

The control circuit 40 individually calculates an adjustment amount for each sensor signal to reduce the difference between the signal level at the intersection between the sensor signals and the target level, which occurs when the same magnetic pole passes near the sensors S1 to S3. You may.

However, the deformations of the waveforms of the U-phase, V-phase, and W-phase sensor signals that occur when the same magnetic pole passes near the sensors S1 to S3 are the same, and therefore the phase and signal of the intersection caused by these deformations. The deviation of the level from the design value is the same as each other. Therefore, the control circuit 40 has a common adjustment amount for each sensor signal in order to reduce the difference between the signal level and the target level at the intersection between the sensor signals that occurs when the same magnetic pole passes in the vicinity of the sensors S1 to S3. May be calculated.

In the example of FIG. 9A, the signal level of the intersection uv_t (1) approaches the target level in the adjustment section of the V-phase sensor signal corresponding to the passage of the magnetic poles P1 to P2 in the vicinity of the sensor S2. The adjustment amount is calculated. In this case, the target level is uv_t_avg and the adjustment amount is uv_t (1) -uv_t_avg. This adjustment amount is also applied to each adjustment section of the U-phase and W-phase sensor signals corresponding to when the magnetic poles P1 to P2 pass in the vicinity of the sensors S1 and S3. As shown in FIG. 9A, when a common adjustment amount uv_t (1) -uv_t_avg is applied to each adjustment section of the U-phase, V-phase, and W-phase sensor signals, the signal level at the intersection vw_t (2) is adjusted. There is still a deviation from the target level uv_t_avg. Therefore, as shown in FIG. 9B, the signal level at the intersection vw_t (2) reaches the target level in the adjustment section of the V-phase sensor signal corresponding to when the magnetic poles P2 to P3 pass near the sensor S2. The adjustment amount is calculated so that it approaches. In this case, the target level is vw_t_avg and the adjustment amount is vw_t (1) -vw_t_avg. This adjustment amount is also applied to each adjustment section of the U-phase and W-phase sensor signals corresponding to when the magnetic poles P1 to P2 pass in the vicinity of the sensors S1 and S3. After that, the same adjustment is repeated.

In the example of FIG. 9, since the average values uv_t_avg, vw_t_avg, and woo_t_avg of the signal levels at the intersections are used as the target levels, the signal levels at the intersections between the sensor signals higher than the common level converge to the average value t_avg.

In the examples of FIGS. 7 to 9, the adjustment amount of each sensor signal reduces the difference between the signal level and the target level at the intersection between the sensor signals that occurs when the same magnetic pole passes in the vicinity of two sensors adjacent to each other. It may be calculated to cause. Therefore, in the arrangement of the sensors S1 to S3 as shown in FIG. 7, the adjustment amount of each sensor signal is not the intersection between the V-phase and W-phase sensor signals, but the intersection between the U-phase and V-phase sensor signals or W. It may be calculated based on the signal level at the intersection between the phase and U phase sensor signals.

If there is a variation in the strength of the multiple magnets of the rotor and the phase of each sensor signal deviates from the design value in a specific angular range within that period, the gradient of the sensor signal is positive and negative. With the interval, the signal level of the sensor signal is adjusted in the same direction (increase or decrease).

According to FIGS. 7 to 9, even when the strength of the plurality of magnets of the rotor varies and the phase of each sensor signal deviates from the design value in a specific angular range within the period. The phase of the intersection between the sensor signals can be adjusted to reduce the error from the design value.

With reference to FIGS. 4 to 6, when the position of a certain sensor deviates from the design position and the phase of the corresponding sensor signal deviates uniformly from the design value over the entire period, the phase adjusting device 1 The operation was explained. Further, with reference to FIGS. 7 to 9, when there is a variation in the strength of the plurality of magnets of the rotor and the phase of each sensor signal deviates from the design value in a specific angle range within the period. The operation of the phase adjusting device 1 has been described. Even if the phase of each sensor signal deviates from the design value due to both of these causes, the phase adjusting device 1 similarly adjusts the phase of the intersection between the sensor signals so as to reduce the error with the design value. Can be adjusted.

When the phase of the intersection between the sensor signals has an error with respect to the design value, the phase of the intersection between each sensor signal and the common level also has an error with respect to the design value. According to the phase adjusting device 1 of FIG. 1, by adjusting the phase of the intersection between the sensor signals so as to reduce the error from the design value, as can be seen from FIGS. 7 and 9, each sensor signal and the common level It is also possible to reduce the error between the phase of the intersection with and the design value.

FIG. 10 is a block diagram showing a configuration of a phase adjusting device 1A according to a modified example of the first embodiment of the present invention. The phase adjusting device 1A includes a signal level adjusting circuit 10, an intersection detecting circuit 20, a signal level detecting circuit 30, a control circuit 40A, and an intersection detecting circuit 50. The signal level adjusting circuit 10, the intersection detection circuit 20, and the signal level detection circuit 30 of FIG. 10 are similar to the corresponding components of FIG.

The intersection detection circuit 50 is a second intersection detection means including the comparators 51 to 53. The comparators 51 to 53 detect the phase of the intersection of the signals U1, V1, W1 and the predetermined reference signal level Ref, respectively, and output signals U2, V2, W2 indicating the phase of the detected intersection. The reference signal level Ref is, for example, a common level.

FIG. 11 is a table showing the relationship between the input signal and the output signal of the intersection detection circuit 50 of FIG. The signal U2 output from the intersection detection circuit 50 has a high value or a low value depending on whether or not the signal U1 input to the intersection detection circuit 50 is equal to or higher than the reference signal level Ref. The rising and falling edges of the signal U2 indicate the phase of the intersection of the signal U1 and the reference signal level Ref. Similar to the signal U2, the signal V2 indicates the phase of the intersection of the signal V1 and the reference signal level Ref, and the signal W2 indicates the phase of the intersection of the signal W1 and the reference signal level Ref.

The control circuit 40A has a boundary for each of the U-phase, V-phase, and W-phase sensor signals at the phase of the intersection of the other sensor signals and the predetermined reference signal level Ref for each period of the sensor signals. Divide into multiple adjustment sections. In other respects, the control circuit 40A operates in the same manner as the control circuit 40 of FIG.

Dividing each cycle of the sensor signal into a plurality of adjustment sections means that even if the phase of the intersection included in the adjustment section changes due to the adjustment of the signal level of the sensor signal in a certain adjustment section, the intersection is the same. It can be done in any way as long as it stays within the section.

Embodiment 2.
FIG. 12 is a block diagram showing a configuration of a phase detection device according to a second embodiment of the present invention. The phase detection device of FIG. 12 includes a phase adjustment device 1, an intersection detection circuit 110, a selection circuit 120, an intersection detection circuit 130, a synthesis circuit 140, and a switch SW. The phase detection device of FIG. 12 detects the phases of the U-phase, V-phase, and W-phase sensor signals acquired from the sensors S1 to S3 provided in the motor M1, and thereby detects the rotation angle of the rotor of the motor M1. Is detected.

The phase adjusting device 1 of FIG. 12 is configured in the same manner as the phase adjusting device 1 of FIG. The phase adjusting device 1 outputs signals U1, V1 and W1, and further outputs signals UV, VW and WU. In FIG. 12, the input device 2 of FIG. 1 is omitted for simplification of the illustration.

The intersection detection circuit 110 is a second intersection detection means including the comparators 111 to 113. The intersection detection circuit 110 is configured in the same manner as the intersection detection circuit 50 in FIG. 10, and operates in the same manner. The intersection detection circuit 110 outputs signals U2, V2, and W2.

The selection circuit 120 and the switch SW select the sensor signal having the highest linearity among the signals U1, V1 and W1 in each of the plurality of detection sections having a boundary at the phase of the intersection between the signals U1, V1 and W1. It is a means of choice. The selection circuit 120 determines a plurality of detection sections based on the signals UV, VW, and WU output from the intersection detection circuit 20, and selects one of the signals U1, V1, and W1 by the switch SW in each detection section. Then, the selected signal X is sent to the intersection detection circuit 130. FIG. 14 is a table showing conditions for selecting signals U1, V1 and W1 by the selection circuit 120 of FIG.

The intersection detection circuit 130 is an intersection of a sensor signal selected by the selection circuit 120 and a plurality of threshold signal levels corresponding to a plurality of different phases included in the detection section in each of the plurality of detection sections. This is a third intersection detection means for detecting the phase.

FIG. 13 is a circuit diagram showing the configuration of the intersection detection circuit 130 of FIG. The intersection detection circuit 130 includes three voltage sources 133, 134, 135, a plurality of 2N + 1 resistors 137-1 to 137-N, 138, 138-1 to 138-N, and a plurality of 2N resistors connected in series with each other. The comparators 131-1 to 131-N and 132-1 to 132-N are provided. For example, the voltage VR1 of the voltage source 134 is set to the common level, the voltage VR0 of the voltage source 133 is set to the minimum value of the signal level of the signals U1, V1, W1, and the voltage VR2 of the voltage source 135 is set to the signals U1, V1, V1, It is set to the maximum value of the signal level of W1. The voltage sources 133, 134, 135 and resistors 137-1 to 137-N, 138, 138-1 to 138-N generate multiple threshold signal levels. The comparators 131-1 to 131-N and 132-1 to 132-N compare the signal level of the selected signal X with the corresponding threshold signal level, and the signal pH (N) − to indicate the comparison result. Outputs ph (1) − and ph (1) + to ph (N) +.

The plurality of threshold signal levels are, for example, in each of the plurality of detection sections, in a plurality of different phases included in the section corresponding to the detection section in one cycle of the ideal period signal having an ideal waveform. It has multiple values of the corresponding ideal period signal. Here, the "ideal periodic signal" represents a sensor signal of an ideal waveform (for example, a sine wave or a cosine wave) having no error with respect to the design waveform. The plurality of threshold signal levels may be fixed values determined based on a predetermined ideal period signal. For example, when the ideal waveforms of U-phase, V-phase, and W-phase sensor signals are sinusoidal and have a phase difference of 120 degrees of electrical angle from each other, one of the detection sections of a sensor signal is It has a range of electrical angles θ0 to θN. In this case, the plurality of threshold signal levels have a plurality of values of the sine wave corresponding to a plurality of different phases θ = θ0, θ1, θ2, ..., θN included in the range of the electric angles θ0 to θN. The same applies to other detection sections.

FIG. 15 is a table showing the relationship between the normalized threshold signal level and the corresponding phase used in the intersection detection circuit 130 of FIG. When the selected signal X is divided into a plurality of detection sections T1 to T6 having an electric angle of 60 degrees (-30 degrees to +30 degrees) as shown in FIG. 14, for example, in each detection section, for example, in FIG. As shown, a predetermined signal level is assigned every 7.5 degrees of electrical angle. The signal level in FIG. 15 is normalized by the amplitude of the signal X. By using the signal level of FIG. 15 as the threshold signal level, the phases of the signals U1, V1 and W1 can be detected with the phases of the detection sections T1 to T6 further subdivided.

The signals U2, V2, and W2 output from the intersection detection circuit 110 are sent to the synthesis circuit 140 as the first phase information signal phA. The signals UV, VW, and WU output from the intersection detection circuit 20 are sent to the synthesis circuit 140 as a second phase information signal phB. The signals ph (N) − to ph (1) − and ph (1) + to ph (N) + output from the intersection detection circuit 130 are sent to the synthesis circuit 140 as a third phase information signal phC.

The synthesis circuit 140 is a synthesis means for generating a phase information signal Phsyn indicating the phases of a plurality of intersections detected by the intersection detection circuits 20, 110, and 130, respectively. The synthesis circuit 140 synthesizes the first to third phase information signals phA, phB, and phC to generate the phase information signal Phsyn.

FIG. 16 is a timing chart showing a first operation example of the phase detection device of FIG. The signals U1, V1 and W1 are U-phase, V-phase, and W-phase sensor signals adjusted by the signal level adjustment circuit 10. The signals U2, V2, W2 indicate the phase of the intersection of the signals U1, V1, W1 and the common level at the rising edge and the falling edge. The signals UV, VW, and WU indicate the phase of the intersection between the signals U1, V1, and W1 at their rising and falling edges. The signals UV, VW, WU are used to determine a plurality of detection sections T1 to T6 having a phase boundary at the intersection of the signals U1, V1, W1.

In FIG. 16, the thick solid line indicates the signal X selected by the selection circuit 120 and the switch SW. The signal X is the signal having the highest linearity among the signals U1, V1 and W1 in each of the detection sections T1 to T6. The right-pointing arrow shown in the detection section T1 is a threshold signal level corresponding to each of a plurality of different phases included in the detection section. By comparing the substantially linear section of the signal X with the threshold signal level, the phase corresponding to the threshold signal level can be accurately detected.

In FIG. 16, the selected signal X has a waveform represented by sin (α), −30 ≦ α ≦ 30, or sin (α), 150 ≦ α ≦ 210 in each detection section. Even if the detection section is switched and the selected sensor signal changes, the signal X is continuous. The signals ph (N) − to ph (1) − and ph (1) + to ph (N) + output from the intersection detection circuit 130 in FIG. 13 are final because adjacent signals are switched in order. The phase information signal Phsyn can be regarded as a Gray code.

FIG. 17 is a timing chart showing a second operation example of the phase detection device of FIG. Here, a case where the synthesis circuit 140 synthesizes the first to third phase information signals phA, phB, and phC to generate a two-phase encoder signal will be described.

For example, when controlling the stop of a brushless DC motor, it is necessary to detect the rotation angle of the rotor. According to the prior art, a rotary encoder is connected to the rotation axis of the motor to output a two-phase pulse signal having a phase difference of 1/4 period that changes according to the rotation angle, and the edge and high / high / of each pulse signal. The relative rotation angle can be detected based on the low state. However, in the method using the rotary encoder of the prior art, generally, a disk having slits serving as optical windows on the outer peripheral portion at equal intervals and two disks arranged at 1/4 intervals of the slit pitch of the disk are arranged. Since a photo interrupter is used, the cost of additional parts is high.

In the example of FIG. 17, each detection section has an electrical angle of 30 degrees. The intersection detection circuit 130 has four threshold signal levels LV (1) to LV (4) corresponding to the selected signal X and four different phases included in the detection section in each of the plurality of detection sections. ) And the phase of the intersection is detected. The intersection detection circuit 130 outputs signals ph (1) to ph (4) corresponding to the threshold signal levels LV (1) to LV (4), respectively, as a third phase information signal phC. The synthesis circuit 140 synthesizes the first to third phase information signals phA, phB, and phC, and outputs a pair of signals OUT1 and OUT2. Here, the synthesis circuit 140 synthesizes the signals ph (1), ph (3) and the signals UV, VW, WU to generate the signal OUT1, and the signals ph (2), ph (4) and the signals U2, V2. , W2 are combined to generate the signal OUT2. This makes it possible to easily obtain a two-phase encoder signal having a phase difference of 1/4 period from each other without providing an optical encoder.

According to the phase detection device of FIG. 12, by synthesizing the first to third phase information signals phA, phB, and phC, the U can have a higher resolution than, for example, when only the first phase information signal phA is used. The phases of the phase, V phase, and W phase sensor signals can be detected.

According to the phase detection device of FIG. 12, the phase adjustment device 1 adjusts the phase of the intersection between the sensor signals so as to reduce the error with the design value, outputs the signals U1, V1, W1 and outputs each sensor. The signals UV, VW, and WU are output by adjusting the phase of the intersection of the signal and the common level. Therefore, the intersection detection circuit 130 processes the selected signal X based on the signals U1, V1, W1 and the signals UV, VW, and WU to subdivide the U-phase, V-phase, and W-phase sensor signals. The resulting phase can be detected with high accuracy.

The voltages VR0 and VR2 in FIG. 13 may be preset values or may be values determined based on the signal levels of the signals U1, V1 and W1. The latter may be, for example, a value between the signal levels of the intersection, or may be an average value of the signal level of the selected signal among the signals U1, V1 and W1 and the signal level of the other signals. Good. Since the phase adjuster 1 adjusts the signal level of each sensor signal for each adjustment section, the signal level at the intersection between the signals U1, V1 and W1 also changes for each adjustment section, and therefore the selected signal X The signal levels of the maximum and minimum values of are changed for each detection section. By setting appropriate voltages VR0 and VR2 in the intersection detection circuit 130 based on the signal levels of the maximum and minimum values of the signal X, the intersection detection circuit 130 can accurately detect the phase of the intersection.

The adjustment interval is preferably determined so as not to affect the detection of the phase of the intersection by the intersection detection circuit 130. For example, the adjustment section is determined so that the selected signal X does not have a step in each of the detection sections T1 to T6. In other words, for each of the U-phase, V-phase, and W-phase sensor signals, the adjustment section is one of the sections with high linearity from the intersection between the sensor signals to the intersection (that is, one of the detection sections T1 to T6). Is determined to include the entire section). As a result, since a certain amount of adjustment is added to the signal X in one detection section, the intersection detection circuit 130 adjusts the phase of the intersection without causing a step in the signal X even if the signal level of the sensor signal is adjusted. It can be detected accurately. Further, by determining the adjustment section in this way, when the voltages VR0 and VR2 in FIG. 13 are determined based on the signal levels of the signals U1, V1 and W1, the undesired fluctuations of the voltages VR0 and VR2 are reduced and the intersection is detected. The circuit 130 can accurately detect the phase of the intersection.

The example of FIG. 15 shows a case where the intersection detection circuit 130 uses a plurality of threshold signal levels corresponding to the phases of each 7.5 degree electric angle. In order to obtain the phase information signal with higher resolution, the intersection detection circuit 130 may use, for example, a plurality of threshold signal levels corresponding to the phases of each electric angle of 6 degrees or electric angles of 3 degrees.

In the example of FIG. 15, the phase of the intersection of the electric angles 0 degrees is known in the signals U1, V1 and W1, and the phase of the intersection of the electric angles -30 degrees and 30 degrees is known in the signals UV, VW and WU. Therefore, in order to reduce the circuit scale of the intersection detection circuit 130, the detection of the electric angles -30 degrees, 0 degrees, and 30 degrees in the intersection detection circuit 130 may be omitted.

Embodiment 3.
In the second embodiment, the case where the plurality of threshold signal levels are fixed values determined based on a predetermined ideal period signal has been described. However, in the second embodiment, when the phase of a certain sensor signal is uniformly deviated from the design value over the entire period (FIGS. 4 to 6), the following problems may occur. Of the signals U1, V1 and W1 adjusted by the signal level adjustment circuit 10, the detection section in which the signal corresponding to the sensor signal having a phase deviated from the design value is selected is the one cycle of the sensor signal. It contains a section different from the original section that should be included in the detection section. At this time, even if the signal level at the intersection of the signals U1, V1 and W1 matches the target level by adjusting the signal level of the sensor signal, the waveform of the signal between the intersections should be included in this detection section. There is an error with respect to the waveform of the original section of the signal. Since a plurality of threshold signal levels related to this detection section are compared for a section different from the original section of the sensor signal to be included in this detection section, detection is performed using these threshold signal levels. The phase of the target you are trying to reach cannot be detected. Therefore, an error occurs in the phase of the intersection detected by the intersection detection circuit 130.

In the third embodiment, by using a variable threshold signal level, it is possible to detect the phase of a sensor signal with high accuracy even if the phase of a certain sensor signal deviates uniformly from the design value over the entire period. A phase detection device that can be used will be described.

FIG. 18 is a block diagram showing a configuration of a phase detection device according to a third embodiment of the present invention. The phase detection device of FIG. 18 includes an intersection detection circuit 130A and a threshold value adjustment circuit 150 in place of the intersection detection circuit 130 of the phase detection device of FIG.

FIG. 19 is a circuit diagram showing the configuration of the intersection detection circuit 130A of FIG. The intersection detection circuit 130A includes a voltage source 133, 135, a plurality of 2N comparators 131-1 to 131-N, 132-1 to 132-N, and a plurality of M resistors 139-1 connected in series with each other. 139-M and selector circuits SEL1 and SEL2 are provided. Under the control of the threshold adjustment circuit 150, the selector circuit SEL1 applies the voltage VR0 of the voltage source 133 to a node between the resistors 139-1 to 139-M, and between the resistors 139-1 to 139-M. The voltage VR2 of the voltage source 135 is applied to the other nodes. Thereby, a variable upper limit and lower limit of the threshold signal level are set. The voltage source 133,135 and the resistors 139-1 to 139-M generate multiple threshold signal levels with variable values. The selector circuit SEL2 selectively sets a plurality of threshold signal levels to the inverting input terminals of the comparators 131-1 to 131-N and 132-1 to 132-N under the control of the threshold adjustment circuit 150. Apply to.

The threshold value adjusting circuit 150 is a threshold value adjusting means for setting a plurality of threshold value signal levels having variable values in the intersection detection circuit 130. The control circuit 40 notifies the threshold value adjustment circuit 150 of the amount of signal level adjustment by the signal level adjustment circuit 10. The threshold value adjustment circuit 150 is used in one cycle of the ideal cycle signal based on the amount of signal level adjustment by the signal level adjustment circuit 10 related to the signal selected by the selection circuit 120 in each of the plurality of detection sections. The section corresponding to the detection section is specified. When the waveform of the sensor signal has no error with respect to the design value and only the phase of the sensor signal deviates from the design value, if the adjustment amount of the signal level by the signal level adjustment circuit 10 is known, the design value of the phase of the sensor signal is known. The error with respect to can be specified. The threshold value adjusting circuit 150 sets a plurality of threshold values by adding an adjustment amount to a plurality of values of the ideal period signal corresponding to each of a plurality of different phases included in the section of the ideal period signal corresponding to the detection section. The signal level is set in the intersection detection circuit 130.

FIG. 20 is a waveform diagram showing a threshold signal level set in the intersection detection circuit 130A of FIG. The intersection of the ideal V-phase sensor signal and the U-phase and W-phase sensor signals determines a detection interval of 30 degrees to 90 degrees, and 30 degrees, 35 degrees, 40 degrees, ..., In this detection interval. Consider the case of trying to detect a 90 degree phase.

The threshold signal levels Th1 to Th13 are values sin (θ + 120) corresponding to θ = 30 degrees, 35 degrees, 40 degrees, ..., 90 degrees of an ideal V-phase sensor signal having an ideal phase and waveform, respectively. ). The actual V-phase sensor signal uniformly deviates from the design value (ideal V-phase) by an unknown error a over the entire period (sin (θ + 120 + a)). The signal level of the actual V-phase sensor signal is adjusted by adjusting the signal level at the intersection of the signals U1, V1 and W1 so that the signal level matches the threshold signal levels Th1 and Th13 (that is, the target level), respectively. The resulting V-phase signal is obtained. However, the adjusted V-phase signal has an error with respect to the ideal V-phase sensor signal except at the intersection. Therefore, even if the phase of the intersection of the adjusted V-phase signal and the threshold signal levels Th1 to Th13 is detected, these phases are 30 degrees, 35 degrees, 40 degrees, ..., 90 degrees to be detected. Does not match the phase of degrees.

In the third embodiment, instead of the threshold signal levels Th1 to Th13, variable threshold signal levels Th1'to Th13' are set for comparison with the adjusted V-phase signal. The error a of the actual V-phase sensor signal with respect to the ideal V-phase sensor signal can be specified based on the amount of signal level adjustment related to the adjusted V-phase signal. The threshold signal levels Th1'to Th13' are a plurality of values of the actual V-phase sensor signal sin (θ + 120 + a) corresponding to the phases of 30 degrees, 35 degrees, 40 degrees, ..., 90 degrees to be detected, respectively. Indicates the value obtained by adding the adjustment amount of the signal level to.

The variable threshold signal level considering the error a with respect to the design value of the phase of the sensor signal may be stored in the threshold value adjustment circuit 150 as a table, for example. Even if the threshold value adjustment circuit 150 specifies the error a based on the adjustment amount of the signal level and refers to the table based on the error a, the variable threshold value signal level is set in the intersection detection circuit 130. Good. Further, the threshold value adjustment circuit 150 sets a variable threshold value signal level as an intersection detection circuit by referring to a table based on the amount of signal level adjustment by the signal level adjustment circuit 10 without calculating the error a itself. It may be set to 130.

The variable threshold signal level stored in the threshold adjustment circuit 150 may be rewritten from outside the phase detector. The threshold signal level may be rewritten when the environment in which the sensor signal is acquired changes, for example, when harmonics are superimposed on the sensor signal. Thereby, the accuracy of the phase detection device can be improved.

According to the phase detection device according to the third embodiment, not only the phase of the intersection between the sensor signals can be accurately detected, but also the phase of the portion other than the intersection in each detection section can be accurately detected. As a result, in the third embodiment, the phase of the sensor signal can be detected with high accuracy even when the phase of a certain sensor signal is uniformly deviated from the design value over the entire period.

Embodiment 4.
FIG. 21 is a block diagram showing a configuration of a motor drive system according to a fourth embodiment of the present invention. The motor drive system of FIG. 21 includes motor M1, sensors S1 to S3, a motor control circuit 160, a motor drive circuit 170, and components of the phase detection device of FIG.

The motor control circuit 160 and the motor drive system are drive means for driving the motor M1 based on the phase information signal Phsyn generated by the phase detection device. The motor control circuit 160 detects the rotation position and speed of the motor M1 based on the phase information signal Phsyn, and generates a PWM signal to control the motor M1 according to the detected rotation position and speed to drive the motor. Send to 170. The motor drive circuit 170 generates a drive current for rotationally driving the rotor of the motor M1 based on the phase information signal phA and the PWM signal, and selectively causes the drive current to flow through the plurality of motor coils.

Each component of the motor control circuit 160, the motor drive circuit 170, and the phase detector of FIG. 12 constitutes a motor drive device for the motor M1.

FIG. 22 is a circuit diagram showing the configuration of the motor drive circuit 170 of FIG. The motor drive circuit 170 includes a pre-driver 80 and a main driver 90. The motor M1 is, for example, a brushless DC motor. The motor M1 includes U-phase, V-phase, and W-phase coils, and these coils are Y-connected in the motor M1. The other ends of these coils are connected to switch elements 91-96 in the main driver 90. The switch elements 91 to 96 include high-side switch elements 91, 93, 95 connected to the power supply side and low-side switch elements 92, 94, 96 connected to the ground side. The pre-driver 80 includes a control circuit 81 and three drive amplifiers 82, 83, 84. The pre-driver 80 generates switch control signals UH, UL, VH, VL, WH, and WL for driving the switch elements 91 to 96 of each phase and sends them to the main driver 90. The switch control signals UH, UL, VH, VL, WH, and WL form three pairs. The control circuit 81 sets the motor drive circuit 170 in one of a mode of synchronous rectification in the duty cycle of the PWM signal determined by the motor control circuit 160, a mode of turning on only the low side, and a mode of turning off both the high side and the low side. Switch. The control circuit 81 refers to the signal logic of the phase information signal phA in order to switch the motor drive circuit 170 to any of the three modes.

FIG. 23 is a timing chart showing the operation of the motor drive circuit 170 of FIG. 22. FIG. 23 shows an example of switching each state according to the signal logic of the sensor signal of each phase. This is a general driving method as a method for driving a brushless DC motor.

The motor control circuit 160 controls an appropriate duty cycle of the above-mentioned PWM signal based on the most accurate phase and position information of the rotating motor M1 and sends the PWM signal to the motor drive circuit 170. The motor control circuit 160 is not provided, and a drive voltage is input to the motor drive circuit 170 instead of the PWM signal. In the motor drive circuit 170, the input drive voltage is compared with a triangular wave having a constant frame period. May generate a PWM signal.

In the motor drive system of FIG. 21, the sensors S1, S2, and S3 can be shared with the phase switching sensor required to drive the brushless DC motor. In the motor drive system of FIG. 21, a phase information signal having a higher resolution than the conventional one can be used without an additional sensor.

FIG. 24 is a block diagram showing a configuration of a motor drive system according to a modified example of the fourth embodiment of the present invention. In the motor drive system of FIG. 24, components other than the motor M1, sensors S1 to S3, and the motor control circuit 160 in the motor drive system of FIG. 21 are integrated as a semiconductor integrated circuit 180. Generally, the motor drive circuit 170 is originally integrated as a semiconductor integrated circuit. By incorporating the phase adjusting device 1, the intersection detection circuits 110 and 130, the selection circuit 120, and the synthesis circuit 140 therein, further integration can be realized with almost no increase in dimensions. Further, the motor drive system can be miniaturized because the optical encoder is eliminated.

The example of integrating as a semiconductor integrated circuit is not limited to the configuration shown in FIG. 24, and for example, only the phase adjusting device 1, the intersection detection circuits 110 and 130, the selection circuit 120, and the synthesis circuit 140 may be integrated. In addition to the configuration shown in FIG. 24, the motor control circuit 160 may be integrated. Since the motor drive circuit 170 that drives the drive phase coil serves as a heat generation source, in some cases, only the motor drive circuit 170 may be separated from the semiconductor integrated circuit.

The motor drive system of FIGS. 21 and 24 may include each component of the phase detector of FIG. 18 instead of the phase detector of FIG.

Embodiment 5.
FIG. 25 is a diagram showing a configuration of an image forming apparatus according to a fifth embodiment of the present invention. The phase adjusting device, the phase detecting device, and the motor driving device according to each of the above-described embodiments may be incorporated in any electronic device including the motor, for example, an image forming device. The image forming apparatus of FIG. 25 includes a plurality of motors, and further includes a phase adjusting device, a phase detecting device, and a motor driving device according to each of the above-described embodiments to drive these motors.

The image forming apparatus shown in FIG. 25 is a tandem type intermediate transfer type image forming apparatus 200 using an electrophotographic method. The image forming apparatus 200 includes an image reading unit 250, an image forming unit 260, a paper feeding unit 270, and a paper ejection unit 280.

The image forming unit 260 includes an image forming unit 201Y, 201M, 201C, 201Bk, an optical writing unit 206A, a transfer unit 207A, a belt cleaning device 209, and a toner replenishment container 212Bk, 212C, 212M, 212Y. The image forming units 201Y, 201M, 201C, 201Bk include photoconductor drums 202Y, 202M, 202C, 202Bk, charging rollers 203Y, 203M, 203C, 203Bk, developing devices 204Y, 204M, 204C, 204Bk, and cleaning devices 205Y, 205M, It is equipped with 205C and 205Bk, respectively. The cleaning devices 205Y, 205M, 205C, 205Bk include a cleaning blade 205a, a storage container 205b, and the like, respectively. The transfer unit 207A includes an intermediate transfer belt 207, support rollers 211a and 211b, and primary transfer rollers 208Y, 208M, 208C and 208Bk. The belt cleaning device 209 includes a cleaning blade 209a, a transport coil 209b, and a cleaning opposing roller 209c.

The paper feed unit 270 includes a paper feed cassette 217a and 217b, a paper feed roller 218, a separation roller 219, and a manual feed tray 222. The paper feed cassettes 217a and 217b accommodate the paper P.

The apparatus main body 245 of the image forming apparatus 200 includes components for transporting the paper P along the normal transport path 229 or the double-sided transport path 230. The components for transporting the paper P include a secondary transfer unit 210A, a fixing unit 213, a transport roller pair 220, 228a, 228b, 228c, a resist roller 221 and a paper feed roller 223, and a switching claw 226a, 226b. The secondary transfer unit 210A includes a secondary transfer roller 210 and a secondary transfer unit 210a. The fixing unit 213 includes a fixing roller 214 and a pressure roller 215.

The paper ejection unit 280 includes a paper ejection roller pair 224a, 224b, 225, and a second paper ejection tray 241.

The apparatus main body 245 of the image forming apparatus 200 further includes a control unit 235, an image density sensor 216, and a temperature / humidity sensor 242.

Inside the image forming apparatus 200, various motors such as a motor for driving the photoconductor drums 202Y, 202M, 202C, and 202Bk and a motor for driving the paper feed roller 218 are provided. In order to drive these motors, the phase adjusting device, the phase detecting device, and the motor driving device according to each of the above-described embodiments are provided inside the control unit 235.

The image forming apparatus of FIG. 25 is not limited to the electrophotographic image forming apparatus described above, and is, for example, an image of a printer, a plotter, a word processor, a facsimile, a copying machine, or the like, or a multifunction device having two or more of these functions. It can also be applied to forming devices.

The phase adjusting device, the phase detection device, and the motor driving device according to each of the above-described embodiments are incorporated in a transport device including a transport roller for transporting a sheet-shaped prepreg or a bill, and a motor for driving the prepreg. May be good. The phase adjusting device, the phase detecting device, and the motor driving device according to each of the above-described embodiments are applied not only to the image forming device and the transport device, but also to devices in other fields including motors such as automobiles, robots, and amusement machines. May be done.

Modification example.
In the above description, the rotor M1a of the motor M1 has six magnetic poles, and the sensors S1 to S3 generate W-phase, U-phase, and V-phase sensor signals in order according to the rotation of the rotor M1a. Each sensor signal had a phase difference of 120 degrees of electrical angle with each other. However, the configuration of the present invention is not limited to this. For example, the rotor M1a has 10 magnetic poles, and the sensors S1 to S3 are arranged so as to generate U-phase, V-phase, and W-phase sensor signals in order, and each sensor signal has a phase difference of 60 degrees of electrical angle. May have each other. The principle described herein can be applied to a general three-phase brushless motor as long as the sensor signals have a phase difference of 90 degrees or more in electrical angle.

The waveform of each sensor signal is not limited to a sine wave, and may be a waveform conforming to a sine wave or a waveform conforming to a trapezoidal wave. The magnetic flux density generated by the rotation of the rotor M1a often changes in a sinusoidal shape, and therefore each sensor signal also often has a sinusoidal shape. However, the magnetic flux density and the sensor signal generated by the rotation of the rotor M1a are not necessarily accurate sine waves, but may be distorted sine waves. Further, the sensor signal may be saturated and have a waveform close to a trapezoidal wave due to magnetic saturation caused by the magnetic flux density detected by the sensors S1 to S3 exceeding the permissible value. The principle described herein can be applied to a sensor signal having an arbitrary waveform as long as the signal level at the intersection deviates from the design value in response to the phase of the intersection between the sensor signals deviating from the design value. Is. The closer the signal is to a sine wave, the easier it is to calculate the amount of signal level adjustment. In the example of FIG. 16, an accurate phase between sensor signals can be detected if the signal has a sine wave or a waveform close to that of a sine wave in a section of an electric angle of −60 degrees to +60 degrees. Similarly, the amount of signal level adjustment can be easily calculated even if it is close to a trapezoidal wave instead of a sine wave.

In the above description, it is assumed that each sensor signal is a sine wave having a single frequency, but in reality, each sensor signal may have various harmonic components added to it. In order to apply the principle described in the present specification to such a sensor signal, the harmonic component may be observed and the calculation coefficient considering the harmonic component may be notified to the control circuit 40 to calculate the adjustment amount. .. As a result, the accuracy of adjusting the phase of the intersection between the sensor signals can be improved.

The sensors S1 to S3 may be shared with the sensor used for switching the commutation current of the multi-phase coils of the motor M1. As a result, it is not necessary to newly add the sensors S1 to S3, so that the cost of additional parts can be reduced.

The phase adjusting device 1 may further include an amplifier circuit for equalizing the signal levels of the U-phase, V-phase, and W-phase sensor signals in front of the signal level adjusting circuit 10. The U-phase, V-phase, and W-phase sensor signals from the sensors S1, S2, and S3 may have non-uniform common levels or amplitudes with each other. Also, each sensor signal may have a very small electrical amplitude. By making the signal levels of the sensor signals uniform with each other and increasing the amplitude, the phase of each sensor signal can be detected more accurately.

The phase adjusting device 1 is not limited to the sensor signals acquired from the sensors S1 to S3 provided in the motor M1, but is a plurality of periodic signals having phase differences with each other and changing periodically and continuously in the same period. If so, the phase of the intersection between arbitrary periodic signals can be adjusted.

The number of magnetic poles of the rotor of the motor M1 and the positions of the sensors S1 to S3 in the motor M1 may be preset in the control circuit 40 via the input device 2, and instead, the period of the signal level at the intersection may be set in advance. It may be determined by the control circuit 40 itself based on the sex. In the latter case, the convenience of the phase adjusting device 1 is improved because the setting via the input device 2 becomes unnecessary.

According to the phase adjusting device, the phase detecting device, the motor driving device, the motor driving system, the image forming device, and the conveying device according to the aspect of the present invention, the following configurations are provided.

According to the phase adjusting device according to the first aspect of the present invention.
A phase adjusting device that adjusts the phase of an intersection between a plurality of periodic signals that have a phase difference from each other and change periodically and continuously in the same period.
A signal level detecting means for detecting the signal level at the intersection, and
A signal level adjusting means for adjusting the signal level of at least one periodic signal among the plurality of periodic signals is provided.
In the signal level adjusting means, in each of the plurality of adjustment sections based on the phases of the plurality of periodic signals, the signal level at the intersection of the two periodic signals of the plurality of periodic signals has a difference from the target level. Then, the signal level of one of the two periodic signals is adjusted so as to reduce the difference.

According to the phase adjusting device according to the second aspect of the present invention, in the phase adjusting device according to the first aspect,
A plurality of adjustment intervals are determined for each of the plurality of periodic signals.
The plurality of adjustment intervals determined for any one of the plurality of periodic signals have a boundary in the phase of the intersection between the other two periodic signals of the plurality of periodic signals. It is a feature.

According to the phase adjusting device according to the third aspect of the present invention, in the phase adjusting device according to the first aspect,
A plurality of adjustment intervals are determined for each of the plurality of periodic signals.
The plurality of adjustment sections determined for any one of the plurality of periodic signals are bounded at the phase of the intersection of the other periodic signal of the plurality of periodic signals and a predetermined reference signal level. It is characterized by having.

According to the phase adjusting device according to the fourth aspect of the present invention, in the phase adjusting device according to one of the first to third aspects,
The plurality of periodic signals are obtained from a plurality of magnetic sensors provided with a predetermined angle difference around the rotation axis in a motor provided with rotors having a predetermined number of magnetic poles, and the rotation of the rotors. It is characterized in that it represents each change in magnetic flux caused by.

According to the phase adjusting device according to the fifth aspect of the present invention, in the phase adjusting device according to the fourth aspect,
The target level is determined based on the number of magnetic poles of the rotor, the positions of the plurality of magnetic sensors in the motor, and the maximum and minimum values of the plurality of periodic signals.

According to the phase adjusting device according to the sixth aspect of the present invention, in the phase adjusting device according to the fourth aspect,
The plurality of periodic signals have one or a plurality of intersections including a plurality of intersections predetermined to have the same signal level among the intersections between the plurality of periodic signals.
The target level is a signal level of an intersection included in the intersection group, and is an average value of signal levels detected by the signal level detecting means.

According to the phase detector according to the seventh aspect of the present invention.
The phase adjusting device according to one of the first to sixth aspects, and
A first intersection detecting means for detecting the phase of an intersection between the plurality of periodic signals output from the signal level adjusting means, and
A second intersection detecting means for detecting the phase of the intersection of the plurality of periodic signals output from the signal level adjusting means and a predetermined reference signal level, and
The most linear of the plurality of periodic signals output from the signal level adjusting means in each of the plurality of detection sections having a boundary in the phase of the intersection between the plurality of periodic signals output from the signal level adjusting means. A selection means for selecting a periodic signal with high potential, and
In each of the plurality of detection sections, the phase of the intersection of the periodic signal selected by the selection means and the plurality of threshold signal levels corresponding to the plurality of different phases included in the detection section is detected. 3 intersection detection means and
It is characterized by including a synthesis means for generating a phase information signal indicating the phases of a plurality of intersections detected by the first to third intersection detection means.

According to the phase detection device according to the eighth aspect of the present invention, in the phase detection device according to the seventh aspect,
The plurality of threshold signal levels are set to a plurality of different phases included in the section corresponding to the detection section in one cycle of the ideal period signal having an ideal waveform in each of the plurality of detection sections. It is characterized by having a plurality of values of the corresponding ideal period signals.

According to the phase detection device according to the ninth aspect of the present invention, in the phase detection device according to the seventh aspect,
The phase detection device further includes a threshold value adjusting means for setting the plurality of threshold value signal levels having variable values to the third intersection detection means.
The threshold value adjusting means is
In each of the plurality of detection sections, one cycle of an ideal periodic signal having an ideal waveform based on the amount of signal level adjustment by the signal level adjusting means related to the periodic signal selected by the selecting means. Identify the section corresponding to the detection section and
The value obtained by adding the adjustment amount to the plurality of values of the ideal period signal corresponding to each of the plurality of different phases included in the section of the ideal period signal corresponding to the detection section is defined as the plurality of threshold signal levels. It is characterized in that it is set in the third intersection detecting means.

According to the motor drive device according to the tenth aspect of the present invention.
A motor drive device for driving a motor having a rotor having a predetermined number of magnetic poles.
A plurality of magnetic sensors provided around the rotation axis of the motor having predetermined angular differences with each other, and generating the plurality of periodic signals representing changes in magnetic flux caused by the rotation of the rotor. Magnetic sensor and
A phase detector according to one of the seventh to ninth aspects, and
It is characterized by including a driving means for driving the motor based on the phase information signal.

According to the motor drive system according to the eleventh aspect of the present invention.
The motor drive device according to the tenth aspect and
It is characterized by being provided with a motor.

According to the image forming apparatus according to the twelfth aspect of the present invention.
The motor drive system according to the eleventh aspect is provided.

According to the transport device according to the thirteenth aspect of the present invention.
The motor drive system according to the eleventh aspect is provided.

1,1A ... Phase adjuster,
2 ... Input device,
10 ... Signal level adjustment circuit,
11 ... U-phase signal level adjustment circuit,
12 ... V-phase signal level adjustment circuit,
13 ... W phase signal level adjustment circuit,
11a to 13a ... Operational amplifier,
11b to 13b ... Variable voltage source,
20 ... Intersection detection circuit,
21-23 ... Comparator,
30 ... Signal level detection circuit,
40, 40A ... Control circuit,
50 ... Intersection detection circuit,
51-53 ... Comparator,
80 ... pre-driver,
81 ... Control circuit,
82, 83, 84 ... Drive amplifier,
90 ... Main driver,
91-96 ... Switch element,
110 ... Intersection detection circuit,
111-113 ... Comparator,
120 ... Selection circuit,
130, 130A ... Intersection detection circuit,
131-1 to 131-N, 132-1 to 132-N ... Comparator,
133, 134, 135 ... Voltage source,
137-1 to 137-N, 138, 138-1 to 138-N, 139-1 to 139-M ... Resistance,
140 ... Synthesis circuit,
150 ... Threshold adjustment circuit,
160 ... Motor control circuit,
170 ... Motor drive circuit,
180 ... Semiconductor integrated circuit,
M1 ... motor,
M1a ... Rotor,
P1 to P6 ... Magnetic poles,
R11 to R14, R21 to R24, R31 to R34 ... Resistors,
S1, S2, S3 ... Sensor,
SEL1, SEL2 ... Selector circuit,
SW ... switch,
201Y, 201M, 201C, 201Bk ... Image forming unit (image forming means),
202Y, 202M, 202C, 202Bk ... Photoreceptor drum (an example of an image carrier),
203Y, 203M, 203C, 203Bk ... Charging roller (an example of charging means and charging device),
204Y, 204M, 204C, 204Bk ... Developing device (development means, example of developing device),
205Y, 205M, 205C, 205Bk ... Cleaning device,
206A ... Optical writing unit (an example of exposure means),
207A ... Transfer unit,
207 ... Intermediate transfer belt (an example of an intermediate transfer body),
208Y, 208M, 208C, 208Bk ... Primary transfer roller (an example of primary transfer means and primary transfer device),
209 ... Belt cleaning device,
210 ... Secondary transfer roller (an example of secondary transfer means and secondary transfer device),
210A ... Secondary transfer unit,
210a ... Secondary transfer unit,
213 ... Fixing unit (an example of fixing means and fixing device),
217a, 217b ... Paper cassette,
221 ... Resist roller,
229 ... Normal transport path,
230 ... Double-sided transport path,
235 ... Control unit (an example of a control device),
242 ... Temperature / humidity sensor (an example of absolute humidity detection means),
245 ... Device body,
250 ... Image reader,
260 ... Image forming unit (an example of image forming means),
270 ... Paper feed section,
280 ... Paper ejection section,
290 ... Paper feed carrier,
P ... Paper (an example of transfer material and sheet).

Japanese Unexamined Patent Publication No. 2013-099023 Japanese Patent No. 4453758 Japanese Patent No. 4780038

Claims (10)

A phase adjusting device that adjusts the phase of an intersection between a plurality of periodic signals that have a phase difference from each other and change periodically and continuously in the same period.
A signal level detecting means for detecting the signal level at the intersection, and
A signal level adjusting means for adjusting the signal level of at least one periodic signal among the plurality of periodic signals is provided.
In the signal level adjusting means, in each of the plurality of adjustment sections based on the phases of the plurality of periodic signals, the signal level at the intersection of the two periodic signals of the plurality of periodic signals has a difference from the target level. When adjusting the signal level of one of the two periodic signals so as to reduce the difference ,
The plurality of periodic signals are obtained from a plurality of magnetic sensors provided with a predetermined angle difference around the rotation axis in a motor provided with rotors having a predetermined number of magnetic poles, and the rotation of the rotors. Represents the changes in magnetic flux caused by
The plurality of periodic signals have a plurality of intersections including a plurality of intersections predetermined to have the same signal level among the intersections between the plurality of periodic signals.
The target level includes a first target level higher than the common level, which is the median of the maximum and minimum values of the periodic signal, and a second target level lower than the common level.
The first target level is the signal level of the intersection included in the intersection group higher than the common level, and is the average value of the signal levels detected by the signal level detecting means.
The second target level is a signal level of intersections included in a group of intersections lower than the common level, and is a phase adjustment characterized by being an average value of signal levels detected by the signal level detecting means. apparatus. A plurality of adjustment intervals are determined for each of the plurality of periodic signals.
The plurality of adjustment intervals determined for any one of the plurality of periodic signals have a boundary in the phase of the intersection between the other two periodic signals of the plurality of periodic signals. The phase adjusting device according to claim 1. A plurality of adjustment intervals are determined for each of the plurality of periodic signals.
The plurality of adjustment intervals determined for any one of the plurality of periodic signals are bounded at the phase of the intersection of the other periodic signal of the plurality of periodic signals and a predetermined reference signal level. The phase adjusting device according to claim 1, wherein the phase adjusting device comprises. The phase adjusting device according to one of claims 1 to 3 and
A first intersection detecting means for detecting the phase of an intersection between the plurality of periodic signals output from the signal level adjusting means, and
A second intersection detecting means for detecting the phase of the intersection of the plurality of periodic signals output from the signal level adjusting means and a predetermined reference signal level, and
The most linear of the plurality of periodic signals output from the signal level adjusting means in each of the plurality of detection sections having a boundary in the phase of the intersection between the plurality of periodic signals output from the signal level adjusting means. A selection means for selecting a periodic signal with high potential, and
In each of the plurality of detection sections, the phase of the intersection of the periodic signal selected by the selection means and the plurality of threshold signal levels corresponding to the plurality of different phases included in the detection section is detected. 3 intersection detection means and
A phase detecting apparatus including a synthesis means for generating a phase information signal indicating the phases of a plurality of intersections detected by the first to third intersection detecting means. The plurality of threshold signal levels are set to a plurality of different phases included in the section corresponding to the detection section in one cycle of the ideal period signal having an ideal waveform in each of the plurality of detection sections. The phase detection device according to claim 4 , wherein the phase detection device has a plurality of values of the corresponding ideal period signals. The phase detection device further includes a threshold value adjusting means for setting the plurality of threshold value signal levels having variable values to the third intersection detection means.
The threshold value adjusting means is
In each of the plurality of detection sections, one cycle of an ideal periodic signal having an ideal waveform based on the amount of signal level adjustment by the signal level adjusting means related to the periodic signal selected by the selecting means. Identify the section corresponding to the detection section and
The value obtained by adding the adjustment amount to the plurality of values of the ideal period signal corresponding to the plurality of different phases included in the section of the ideal period signal corresponding to the detection section is defined as the plurality of threshold signal levels. The phase detection device according to claim 4 , wherein the phase detection device is set to the third intersection detection means. A motor drive device for driving a motor having a rotor having a predetermined number of magnetic poles.
A plurality of magnetic sensors provided around the rotation axis of the motor having predetermined angular differences with each other, and generating the plurality of periodic signals representing changes in magnetic flux caused by the rotation of the rotor. Magnetic sensor and
The phase detector according to any one of claims 4 to 6 ,
A motor driving device including a driving means for driving the motor based on the phase information signal. The motor drive device according to claim 7 and
A motor drive system characterized by being equipped with a motor. An image forming apparatus comprising the motor drive system according to claim 8 . A transport device including the motor drive system according to claim 8 .

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