JP4421250B2 - High frequency inverter device - Google Patents

Description

The present invention relates to a high-frequency inverter device including a switching element connected pair of serially.

Harmonic countermeasures in, for example, an electronic ballast for lighting that uses a low-frequency AC power source such as a commercial AC power source to light a discharge lamp at a high frequency are classified into a passive filter method, an active filter method, and a partial smoothing method. The active filter method includes a chopper method, a charge pump method, and a charge pump + chopper method.
"Journal of the Illuminating Society of Japan" Vol. 84, No. 5, issued in May 2000, pp. 273-280 "Analysis of the operation of an inverter-type lighting circuit combined with a chopper"

  However, in a passive filter, a series inductor and a parallel capacitor are connected to a load and circuit constants are selected so that their resonance frequency resonates three times the power supply frequency. In particular, the inductor has a large power capacity. Since something is required, it is impossible to reduce the size and weight.

  In the active filter, in the case of the chopper type, an independent step-up chopper circuit is provided separately from the inverter, so that the number of parts increases and the cost increases. The charge pump method and the charge pump + chopper method are so-called composite types in which the switching element of the inverter is also used as the switching element of the active filter, but the circuit configuration is complicated and sufficient smoothing action cannot be obtained. There are problems such as.

  The partial smoothing circuit cannot satisfy the recent strict input current harmonic standards.

  The present invention includes a high-frequency inverter device including a neutral point step-down non-inverting inverter, low harmonic distortion, easy supply of sufficient high-frequency power, and a simple circuit configuration, and a discharge lamp lighting device using the same The purpose is to provide.

High-frequency inverter device of the invention of claim 1, together are forming a series circuit of the series circuit and a pair of rectifying elements of the pair of switching elements alternately switching at a high frequency are connected in parallel, the connection point of the pair of switching elements and between the connection point of the pair of rectifying elements, a low-frequency AC power source and the inductor and the bridge rectifier-converter circuit with a series circuit of the load; the inductor and the first rectifier element and the first small-capacity made a series circuit of a capacitor, the series of first second rectifying element and the second small capacitor polarity with respect to the inductor and the feedback circuit element has a polarity opposite to that of the first rectifying element connected in parallel to said inductor a feedback circuit and a second feedback circuit elements connected in parallel to said inductor consists circuit, and the pair of switching elements A connection between the connection point of the first rectifying element and the first small-capacitance capacitor of the feedback circuit in the chopper circuit and the connection point of the second rectification element and the second small-capacitance capacitor of the feedback circuit. And a third rectifying element and a third rectifying element interposed in a forward direction between a series circuit of the smoothing capacitor and a pair of switching elements.

  In the present invention and each of the following inventions, the definitions and technical meanings of terms are as follows unless otherwise specified.

  In the present invention, “high frequency” means a frequency of 1 kHz or more, preferably 20 kHz or more exceeding the limit of the audible frequency, more preferably 40 kHz or more higher than the carrier frequency of the remote control.

  <Bridge type rectification / conversion circuit> The bridge type rectification / conversion circuit rectifies low-frequency alternating current and converts it into direct current, and also converts direct current into high frequency by switching. Operates as an inverter. In order to convert low-frequency alternating current into direct current, a pair of rectifying elements mainly acts. A pair of switching elements acts to convert direct current to high frequency.

  The pair of switching elements may be either directly connected in series or indirectly connected in series via another circuit element such as a resistor. In addition, the pair of switching elements and the pair of rectifying elements only need to be able to function as a pair in terms of function, and both or either of the pair is allowed to be configured by a plurality of elements. Furthermore, the switching element may have any configuration as long as it is a controllable switching element that can be switched at a high frequency. For example, a bipolar transistor, an FET, or the like can be used.

Low-frequency AC power source may be connected solely between AC input terminal of the bridge rectifier-converter circuit is connected to a load such as inductors and discharge electric lamps chopper circuit through the series.

  <About the Chopper Circuit> In the present invention, the “chopper circuit” refers to feedback of a counter electromotive force generated between both ends of an inductor by switching of a DC current, and converts a DC voltage of a certain voltage into another DC voltage having a different voltage. Means to do. A step-down chopper circuit is formed by the circuit configuration described below.

  That is, the inductor may be dedicated to the chopper or may also serve as the output transformer. A feedback circuit for feeding back the counter electromotive force is composed of first and second feedback circuit elements. The first feedback circuit element includes a series circuit of a first rectifying element and a first small-capacitance capacitor, and is mainly connected in parallel to the inductor so as to operate when the low-frequency AC voltage has one polarity. The polarity is selected. On the other hand, the second feedback circuit element is composed of a series circuit of a second rectifier element and a second small-capacitance capacitor, and is connected in parallel to the inductor, but the polarity with respect to the inductor is the first rectifier element. Therefore, the polarity of the rectifying element is selected so as to operate mainly when the low-frequency AC voltage is the other polarity. The first and second feedback circuits perform feedback when the rectifying element is in the forward direction with respect to the polarity of the counter electromotive force of the inductor. In short, the first and second feedback circuit elements are alternately responsible for the feedback action according to the polarity of each half wave of the low-frequency AC voltage. In the present invention, the term “small capacitor” means that the capacitance is relatively small, and substantially no smoothing effect is obtained with respect to the low-frequency AC voltage. A capacitor.

  <Smoothing Capacitor> The smoothing capacitor is disposed so as to be charged by the feedback current of the chopper circuit and further converted to a high frequency by the pair of switching elements. Therefore, the smoothing capacitor is connected to the output terminal of the feedback circuit. Between the connection point of the first rectifying element and the first small-capacitance capacitor of the first feedback circuit element and the connection point of the second rectification element and the second small-capacitance capacitor of the second feedback circuit element. It is connected to the. Further, the smoothing capacitor has a relatively large capacitance, such as an electrolytic capacitor, and has an effect of smoothing the feedback voltage at least partially.

  <Regarding the Third and Fourth Rectifying Elements> The third and fourth rectifying elements are interposed between the smoothing capacitor and the series circuit of the pair of switching elements in the forward direction, and are a pair of bridge-type rectifying / converting circuits. The low-frequency alternating current rectified by the rectifier element is prevented from wrapping around the smoothing capacitor, and a discharge path for the charge of the smoothing capacitor and the first and second small-capacitance capacitors of the feedback circuit of the feedback circuit is provided.

  <Operation of the Present Invention> Since the present invention has the above-described configuration, the low-frequency AC voltage is full-wave rectified and switched at a high frequency in the bridge-type rectification / conversion circuit.・ Step-down converter operation is performed by the conversion circuit.

  In addition, a low-frequency alternating current that has been increased in frequency by switching flowing from a low-frequency alternating current power source and a high-frequency current generated by the chopper circuit flow bidirectionally in the inductor of the chopper circuit. Since the inductor only needs to have an impedance effective only for a high-frequency current due to switching of the switching element, the low-frequency AC power supply can operate without being substantially short-circuited. Therefore, the inductor of the chopper circuit can be reduced in size and weight.

  Further, the back electromotive force generated in the inductor of the chopper circuit by the alternating switching in either one of the pair of switching elements according to the polarity of the low frequency AC voltage is small in either one of the first and second feedback circuit elements. The capacitor is fed back to the capacitor and charged, and the smoothing capacitor is further charged. Then, when the DC energy once fed back and once accumulated in the small-capacitance capacitor and the smoothing capacitor is discharged next, the switching interposed in the discharge circuit formed by one of the third and fourth rectifier elements Since the DC energy is converted into a high frequency by switching the element, the load is energized by the high frequency voltage.

  Next, when the polarity of the low-frequency AC voltage is reversed, the DC energy is fed back to the small-capacitance capacitor in the other of the first and second feedback circuit elements by switching in the other switching element of the pair. As well as a smoothing capacitor. When the DC energy accumulated in the small-capacitance capacitor and the smoothing capacitor is discharged next time, the other switching element interposed in the discharge circuit formed by the other one of the third and fourth rectifying elements. Since direct current energy is converted into high frequency by switching, the load is energized by the high frequency voltage. Next, when one of the pair of switching elements is turned on, the small-capacitance capacitor and the smoothing capacitor of one feedback circuit element are discharged via the load and the one switching element. As a result, at this time, a high-frequency voltage having a substantially constant peak value is generated in the opposite polarity direction.

  Thus, in the steady state of the high frequency inverter device of the present invention, the operation of the feedback circuit and the high frequency conversion is as follows. That is, in the feedback circuit of the chopper circuit, the first and second small capacitors are charged by the counter electromotive force of the inductor as described above. Then, in the half-wave period of the low-frequency AC voltage in which the rectifying element of one feedback circuit element is in the forward direction, when one switching element is turned on, the small-capacitance capacitor in the feedback circuit element to which the switching element belongs When the charging voltage is higher than the instantaneous value of the low-frequency alternating voltage, the charged charge is discharged through the switching element and the one connected to the feedback circuit element among the third and fourth rectifying elements, When the switching element is turned off and the other switching element is turned on, the charge of the small-capacitance capacitor belonging to the other feedback circuit element flows through the other switching element, so that a high-frequency voltage that alternates between positive and negative polarities is generated. The load is energized by the high frequency voltage. When the polarity of the low-frequency AC voltage is reversed, the circuit operation similar to the above is performed by the other feedback circuit element, the fourth or third rectifying element connected to the other feedback circuit element, and the closed circuit of the other switching element, This is performed in one feedback circuit element, the third or fourth rectifying element connected to the feedback circuit element, and the closed circuit of one switching element.

As can be understood from the above description, the high-frequency current that is directly switched by the low-frequency alternating current flowing from the low-frequency alternating-current power supply and the direct-current energy that is fed back to the first and second small capacitors are switched and flown. Since the high-frequency current flows through the load, the load performs a predetermined operation by applying a high-frequency voltage. Therefore, since the load is connected in series with the inductor through which high-frequency alternating current flows, the load can be energized by the high-frequency voltage. Further, if necessary, a resonance circuit can be connected to a circuit portion through which the high-frequency current converted by switching the fed back DC energy flows, and the load can be energized by the resonance output.

  Further, in the present invention, the input current flowing from the low-frequency AC power supply does not cause a rest period throughout the entire period of each half-wave of the low-frequency AC voltage, and also has a sinusoidal shape, so that harmonic distortion is extremely reduced. . Note that the envelope of the generated high frequency voltage changes in a sine wave shape.

  Furthermore, in the present invention, since the feedback circuit of the chopper circuit is arranged separately from the pair of switching elements, even if an FET is used as the switching element, it is not necessary to feed back via the parasitic diode. Increased efficiency. Alternatively, since there is no need to connect a feedback diode to the switching element in parallel, there is no need to mount a feedback circuit near the position where the switching elements and their drive circuits are densely packed. The degree is improved.

  Furthermore, the magnetic energy stored in the inductor is converted to DC energy of the smoothing capacitor without going through a pair of switching elements, and this is used as a power source for generating high frequency, so that it is highly efficient and the degree of freedom in circuit design is high. Get higher.

  Furthermore, since the first and second small-capacitor charging circuits do not exist before the pair of switching elements starts high-frequency switching, no inrush current occurs when the low-frequency AC power supply is turned on. The input current flows almost sinusoidally over the entire half-wave period of the low-frequency AC voltage. For this reason, there is a margin in the power source capacity and the wiring capacity, and since there is no input current pause period, harmonic distortion is reduced.

<Other Configurations> Although not an essential component of the present invention, a more practical high-frequency inverter device and a discharge lamp lighting device using the same can be obtained by adding the following configuration.
1. (Regarding Resonant Circuit) The resonant circuit resonates with a high-frequency voltage formed by alternating switching of a pair of switching elements to provide a load circuit of the high-frequency inverter device. The resonant circuit is formed by an inductor and a capacitor. The “inductor” means a circuit means having inductance, and is not limited to a choke coil. Therefore, a transformer or the like may be used as long as it has an appropriate inductance when viewed from the primary side. Thus, the resonance circuit forms a high voltage by resonance at the start of the load, for example, a discharge lamp, and promotes the start by applying this to the load, and shapes the waveform of the high-frequency voltage into a sine wave. .
2. (High-frequency noise filter circuit) The high-frequency noise filter circuit is a circuit means for preventing high-frequency noise generated by the operation of the high-frequency inverter device from flowing out to the low-frequency AC power supply side. A series-parallel connection can be made between the ends.
3. (Smoothing capacitor) By connecting a smoothing capacitor in parallel to a series circuit of a pair of switching elements, the ripple component of the envelope waveform of the high-frequency voltage applied to the load can be reduced.

A high-frequency inverter device according to a second aspect of the present invention is formed by connecting in parallel a series circuit of a pair of switching elements and a series circuit of a pair of rectifying elements that are alternately switched at a high frequency, and a connection point of the pair of switching elements A bridge-type rectification / conversion circuit in which a low-frequency AC power supply and a series circuit of a primary side of a transformer having a load connected to the secondary side are connected between the connection point of the pair of rectifying elements; The first feedback circuit element connected in parallel to the primary side and the polarity with respect to the primary side is reverse to that of the first rectifier element, comprising a series circuit of a secondary side, a first rectifier element, and a first small-capacitance capacitor. A feedback circuit comprising a second feedback rectifier element having a polarity and a second feedback circuit element connected in parallel to the primary side, and a pair of switches. A connection point between the first rectifying element and the first small-capacitance capacitor in the feedback circuit and a connection point between the second rectifying element and the second small-capacitance capacitor in the feedback circuit. And a third capacitor and a fourth rectifying element interposed in a forward direction between a series circuit of the smoothing capacitor and a pair of switching elements.

As compared with the high-frequency inverter device of the first aspect of the present invention, the inductor is replaced with the primary side of the transformer and a load is connected to the secondary side.

High-frequency inverter device of the invention of claim 3, the load of claim 1, wherein is wherein the discharge lamp der Rukoto.

The discharge lamp operates as a load of the high-frequency inverter device. Any type of discharge lamp may be used. For example, a low pressure discharge lamp such as a fluorescent lamp or a high pressure discharge lamp such as a metal halide lamp may be used. Further, the discharge lamp is connected to a position on the circuit where a resonant output of a high frequency voltage is applied. For example, a half-bridge inverter circuit that shares a pair of switching elements of a bridge-type rectification / conversion circuit and includes a resonance circuit in parallel with the bridge-type rectification / conversion circuit is configured to form an inductor for the resonance circuit. The discharge lamps can be connected in parallel or in series. In addition, a resonance circuit in which the inductor of the chopper circuit is all or part of one of the resonance elements is formed by sharing a part of the bridge type rectification / conversion circuit, and a discharge lamp is connected in parallel or in series with the inductor. Can be connected. In the above connection mode, in order to select and extract only the high-frequency component, a secondary winding is wound around the inductor to form an output transformer, and the discharge lamp is energized via the output transformer. Is desirable.

For example, the discharge lamp allows various connection modes as described below.
(1) A mode in which an AC input terminal of a bridge-type rectification / conversion circuit is connected to both ends of an inductor that also serves as an output transformer, for example.
(2) A mode in which the inductor and the low-frequency AC power supply are connected in series.
(3) A mode in which a half-bridge inverter including a pair of switching elements using a small-capacitance capacitor as a power source is configured and connected to the output terminal.

  Thus, in the present invention, when the low-frequency AC power supply is turned on, the low-frequency AC voltage is rectified and smoothed by the bridge-type rectification / conversion circuit and the chopper circuit, further converted into a high-frequency voltage and applied to the discharge lamp. Therefore, the discharge lamp is lit at high frequency.

  Although not an essential component of the present invention, an igniter can be added if desired. An igniter is used for starting a discharge lamp when the resonance voltage by the resonance circuit of the load circuit is insufficient, and is provided separately from the discharge circuit in a discharge lamp lighting device mainly composed of a high-frequency inverter. Can be connected to the discharge circuit so that a high voltage pulse generated from is applied to the discharge lamp.

According to the first aspect of the present invention, the neutral point type step-down non-inverter in which a low frequency AC power supply voltage of both positive and negative polarity is switched at a high frequency and a series circuit of a low frequency AC power supply, an inductor and a load is connected between the AC input terminals. Since the capacitor of the first and second feedback circuit elements is provided with an inverter and has a small capacity, there is no idle period in the input current. Therefore, a high-frequency inverter device with less harmonic distortion and a simple circuit configuration is provided. Can be provided.

According to the second aspect of the present invention, the low-frequency AC power supply voltage having both positive and negative polarities is switched at a high frequency, and the low-frequency AC power supply is connected in series between the AC input terminal and the primary side of the transformer connected to the secondary side A neutral point step-down non-inverting inverter connected to the circuit is provided, and since the capacitors of the first and second feedback circuit elements have a small capacity, no pause period is generated in the input current, thereby reducing harmonic distortion. Moreover, it is possible to provide a high-frequency inverter device having a simple circuit configuration.

According to invention of Claim 3, the load which has the effect of Claim 1 and Claim 2 can provide the high frequency inverter apparatus of a discharge lamp.

  Embodiments of the present invention will be described below with reference to the drawings.

1 and 2 show a first mode for carrying out the high-frequency inverter device of the present invention, FIG. 1 is a circuit diagram, FIG. 2 shows conceptually an input voltage and current waveforms and the load voltage and current waveforms It is a waveform diagram. In FIG. 1, the high-frequency inverter device HFI includes a bridge-type rectification / conversion circuit BRC, a chopper circuit DCH, and third and fourth rectification elements D5 and D6. The discharge lamp DL in the high-frequency inverter device HFI and load, the constitute a discharge lamp lighting device DLO discharge lamp DL to the high frequency lighting. AC is a low frequency AC power source.

  The bridge type rectification / conversion circuit BRC is formed by connecting a series circuit of a pair of switching elements Q1 and Q2 and a series circuit of a pair of rectification elements D1 and D2 in parallel so as to form a closed circuit in the forward direction. An AC input end is between the connection point j1 of the pair of switching elements Q1 and Q2 and the connection point j2 of the pair of rectifying elements D1 and D2. A low-frequency AC power supply AC is connected in series with an inductor L1 (described later) and a discharge lamp DL as a load to AC input terminals j1 and j2 of the bridge type rectification / conversion circuit BRC shown in the figure.

  The chopper circuit DCH includes an inductor L1, a feedback circuit FBC, and a pair of switching elements Q1 and Q2. The inductor L1 is connected in series with the low frequency AC power supply AC and the discharge lamp DL between the AC input terminals j1 and j2 of the bridge type rectification / conversion circuit BRC. The feedback circuit FBC includes first and second feedback circuit elements FB1 and FB2. The first feedback circuit element FB1 includes a series circuit of a first rectifier element D3 and a first small-capacitance capacitor C1, and is connected in parallel to the inductor L1. Similarly, the second feedback circuit element FB2 is composed of a series circuit of the second rectifier element D4 and the second small-capacitance capacitor C2, but has a polarity opposite to that of the first rectifier element D3 with respect to the inductor L1. Are connected in parallel in different polarities. One switching element Q1 cooperates with the inductor L1 and the first feedback circuit element FB1 to perform a chopper operation during a half wave mainly having one polarity of the low-frequency AC power supply AC in which the connection point j2 is positive. Do. Similarly, the other switching element Q2 mainly performs cooperation with the inductor L1 and the second feedback circuit element FB2 to perform a chopper operation during the half wave having the other polarity where the connection point j1 is positive.

  The third and fourth rectifying elements D5 and D6 supply the DC output current of the chopper circuit FBC, that is, the charges accumulated in the first and second small capacitors C1 and C2 to the switching elements Q1 and Q2 as discharge currents. Providing a discharge path for conversion to high frequency. That is, the third rectifier element D5 provides a discharge path so that the electric charge of the first small-capacitance capacitor C1 flows via the switching element Q1 and the load DL. Similarly, the fourth rectifier element D6 provides a discharge path so that the charge of the second small-capacitance capacitor C2 flows via the switching element Q1 and the load DL.

  Next, circuit operation in this embodiment will be described.

  The circuit operation of the bridge type rectification / conversion circuit BRC is as follows. That is, when the low-frequency AC power supply AC is turned on and the pair of switching elements Q1 and Q2 perform switching operations alternately at a high frequency, the period in which the voltage polarity of the low-frequency AC power supply AC coincides with the forward direction of the rectifying element D1. Therefore, during the half-wave period in which the connection point j2 is positive, the low-frequency AC power supply AC, the rectifying element D1, one switching element Q1, the discharge lamp DL, the inductor L1 of the chopper circuit DCH, and the closed circuit of the low-frequency AC power supply AC A current flows when one of the switching elements Q1 is on, and a voltage drop occurs intermittently across the load L. In other words, a high frequency pulsed low frequency alternating current intermittently flows in one direction from the low frequency alternating current power supply AC to the discharge lamp DL.

  In the switching operation of one switching element Q1, the current flowing through the inductor L1 of the chopper circuit DCH increases linearly during the period when the one switching element Q1 is on. Next, when one switching element Q1 is turned off, a counter electromotive force is generated in the inductor L1 so as to continue the current flowing therethrough. Then, a current flows through the closed circuit of the inductor L1, the first rectifying element D3, the first small-capacitance capacitor C1 and the inductor L1 in the first feedback circuit element FB1, and the first small-capacitance capacitor C1 is charged. The

  Next, when one switching element Q1 is turned on again, the charge of the first small-capacitance capacitor C1 is the first small-capacitance capacitor C1, the third rectifier element D5, the switching element Q1, the discharge lamp DL, and the first Flows as a high-frequency current in a closed circuit consisting of the small-capacitance capacitor C1, that is, in the discharge path.

  Now, during the period in which the polarity of the voltage of the low-frequency AC power supply AC is inverted and coincides with the forward direction of the rectifying element D2, that is, the half-wave period during which the connection point j1 is positive, the low-frequency AC power supply AC, the rectifying element D2, When the other switching element Q2 is turned on in the closed circuit of the other switching element Q2, the discharge lamp DL and the low-frequency AC power supply AC, a current flows, and a voltage drop is intermittently generated at both ends of the discharge lamp DL. In other words, a high frequency pulsed low frequency alternating current intermittently flows in the opposite direction from the low frequency alternating current power supply AC to the discharge lamp DL. Therefore, since the high frequency component flowing between the AC input terminals j1 and j2 of the bridge type rectification / conversion circuit BRC is supplied to the discharge lamp DL, the discharge lamp DL is energized at a high frequency.

  When the other switching element Q2 is turned off, the back electromotive force generated in the inductor L1 of the chopper circuit DCH is accumulated in the second small-capacitance capacitor C2 in the second feedback circuit element FB2, and the other switching element is turned on again. Sometimes, the electric charge is discharged in the closed circuit of the second small-capacitance capacitor C2, the discharge lamp DL, the other switching element Q2, the fourth rectifier element D6 and the second small-capacitance capacitor C2, that is, in the discharge path. Flows through the discharge lamp DL.

  Thus, in the steady operation state of the high-frequency inverter device, the first and second small-capacitance capacitors C1 and C2 of the first and second feedback circuit elements FB1 and FB2 of the chopper circuit DCH are charged. When the charging voltage of the first small-capacitance capacitor C1 of the first feedback circuit element FB1 is higher than the instantaneous value of the low-frequency AC voltage during the positive half-wave period of the connection point j2, the first switching element Q1 When turned on, the electric charge of the first smoothing capacitor C1 is discharged for a short time through the third rectifier element D5, the switching element Q1 and the discharge lamp DL.

  Next, when the switching element Q1 is turned off and the switching element Q2 is turned on, the charge of the second small-capacitance capacitor C2 of the second feedback circuit element FB1 is changed to the fourth rectifying element D6, the switching element Q2, and the discharge lamp DL. As shown in FIG. 2B, a high-frequency load current having both positive and negative polarities flows in the discharge lamp DL, and both positive and negative polarities are applied to both ends of the discharge lamp DL. A high frequency load voltage appears. Therefore, the discharge lamp DL performs high frequency lighting.

  In the circuit operation in the steady state, as shown in FIG. 2B, the current flowing from the low frequency AC power supply AC is directly converted to a high frequency by alternating switching of a pair of switching elements and flows to the discharge lamp DL. As a result of the above circuit operation, as shown in FIG. 2A, the input current i flows from the low frequency AC power source AC throughout the entire period of the low frequency AC voltage.

  Hereinafter, another embodiment for carrying out the present invention will be described with reference to FIGS. In addition, in each figure, the same code | symbol is attached | subjected about the part same as FIG. 1, and description is abbreviate | omitted.

Figure 3 is a circuit diagram showing a second embodiment definitive the high-frequency inverter device of the present invention. In the present embodiment, the connection positions of the first and second rectifying elements D3 and D4 and the first and second small capacitors C1 and C2 in the feedback circuit FBC of the chopper circuit DCH with respect to the inductor L1 are reversed. Is different.

Thus, also in this embodiment, the circuit operation, that is, the input voltage / current and load voltage / current waveforms are substantially the same as those in the first embodiment shown in FIGS.
However, the circuit operation of the first and second feedback circuit elements FB1 and FB2 of the feedback circuit FBC is opposite to that of FIG. 1 for the polarity of each half-wave of the low-frequency AC voltage. That is, in the half wave of the low-frequency AC voltage at which the connection point j2 is positive, the feedback operation for the low-frequency AC current of the input current is mainly handled by the second feedback circuit element FB2, and the connection point j1 is positive. In the half wave of the low frequency alternating voltage, the feedback operation for the low frequency alternating current of the input current is mainly performed by the first feedback circuit element FB1.

Figure 4 is a circuit diagram showing a third embodiment definitive the high-frequency inverter device of the present invention. This embodiment is different in that the discharge lamp DL is turned on via the inductor L1 of the chopper circuit DCH. That is, the inductor L1 of the chopper circuit DCH constitutes the output transformer OT, and the discharge lamp DL as a load is connected to the secondary winding of the output transformer OT. That is, the inductor L1 also serves as the primary winding of the output transformer OT.

  Thus, in the third embodiment, the discharge lamp DL uses a voltage obtained by transforming the high-frequency voltage appearing across the inductor L1 at a step-up ratio corresponding to the primary and secondary turns ratio of the output transformer OT. Light. Therefore, the secondary voltage applied to the discharge lamp as a load can be boosted to a desired value.

Figure 5 is a circuit diagram showing a fourth embodiment definitive the high-frequency inverter device of the present invention. In the present embodiment, the inductor L1 of the chopper circuit DCH constitutes the output transformer OT, and the discharge lamp DL as a load is connected to the secondary winding of the output transformer OT in the third embodiment shown in FIG. However, the connection positions of the first and second rectifying elements D3 and D4 and the first and second small-capacitance capacitors C1 and C2 in the feedback circuit FBC of the chopper circuit DCH to the inductor L1 are reversed. This is the same configuration as the second embodiment shown in FIG.

Circuit diagram showing a first mode for carrying out the high-frequency inverter device of the present invention Similarly, a waveform diagram conceptually showing the input voltage / current waveform and load voltage / current waveform Circuit diagram showing a second mode for carrying out the high-frequency inverter device of the present invention The circuit diagram which shows the 3rd form for implementing the high frequency inverter apparatus and discharge lamp lighting device of this invention Circuit diagram showing a fourth mode for carrying out the high-frequency inverter device of the present invention

AC ... Low frequency AC power supply, BEC ... Bridge type rectification / conversion circuit, DCH ... Chopper circuit, C1 ... First small capacitor, C2 ... Second small capacitor, D3 ... First rectifier element, D4 ... ... second rectifier element, D5 ... third rectifier element, D6 ... third rectifier element, DL ... discharge lamp, DLO ... discharge lamp lighting device, FBC ... feedback circuit, FB1 ... first feedback circuit element , FB2 ... second feedback circuitry, HFI ... high-frequency inverter device, j1, j2 ... attachment point, L1 ... Inkuta, Q1, Q2 ... switching element

Claims (3)

A series circuit together with formed by parallel connection of the series circuit and a pair of rectifying elements of the pair of switching elements alternately switching at a high frequency, a connection point of the pair of switching elements and a connection point of said pair of rectifying elements A bridge-type rectification / conversion circuit in which a low-frequency AC power supply and a series circuit of an inductor and a load are connected in between;
Made a series circuit of the inductor and the first rectifier element and the first small capacitor, the polarity with respect to the inductor and first feedback circuit elements connected in parallel to said inductor has a polarity opposite to that of the first rectifying element A feedback circuit comprising a second feedback circuit element comprising a series circuit of a second rectifier element and a second small-capacitance capacitor and connected in parallel to the inductor; and a chopper circuit including the pair of switching elements;
A smoothing capacitor connected between a connection point of the first rectifying element and the first small-capacitance capacitor of the feedback circuit in the chopper circuit and a connection point of the second rectifying element and the second small-capacitance capacitor of the feedback circuit; ;
Third and fourth rectifying elements interposed in a forward direction between a series circuit of a smoothing capacitor and a pair of switching elements;
A high frequency inverter device comprising: A series circuit of a pair of switching elements that alternately switch at a high frequency and a series circuit of a pair of rectifier elements are formed in parallel, and a connection point between the pair of switching elements and a connection point of the pair of rectifier elements A bridge type rectification / conversion circuit in which a low frequency AC power source and a series circuit of a primary side of a transformer with a load connected to the secondary side are connected in between;
A first feedback circuit element connected in parallel to the primary side and having a polarity with respect to the primary side, comprising a series circuit of the primary side, a first rectifier element, and a first small-capacitance capacitor. A feedback circuit comprising a second feedback circuit element comprising a second circuit having a polarity opposite to that of the second rectifier element and a second small-capacitance capacitor connected in parallel to the primary side, and the pair of switching elements Including a chopper circuit;
A smoothing capacitor connected between a connection point of the first rectifying element and the first small-capacitance capacitor of the feedback circuit in the chopper circuit and a connection point of the second rectifying element and the second small-capacitance capacitor of the feedback circuit; ;
Third and fourth rectifying elements interposed in a forward direction between a series circuit of a smoothing capacitor and a pair of switching elements;
A high frequency inverter device comprising: Load according to claim 1 or claim 2, wherein the discharge lamp der Rukoto high-frequency inverter device according to claim.

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