JPH08162265A - Inverter circuit - Google Patents

Abstract

PURPOSE: To generate a rotary magnetic field and a high frequency magnetic field with one same coil by using a coil to generate a rotary magnetic field and a coil to generate a high frequency magnetic field to carry out induction heating in common and controlling the frequency of flowing electric current only by switching the igniting method of a semiconductor switch. CONSTITUTION: D.c. voltage is applied to points A, B of a switch element module 2. A controlling circuit 5 ignites semiconductor switch elements 2a and 2e. Consequently, the C point becomes at high voltage and the D point becomes at low voltage and current flows from a coil 3a to a coil 3b. A magnetic field is generated due to the current and gives torque to, for example, a rotor. Then, the controlling circuit 5 ignites the switch elements 2c and 2e, the E point becomes at high voltage and the D point becomes at low voltage, current thus flows the coils 3c and 3b, a magnetic field is generated and torque is given to a rotor. Consequently, a rotary magnetic field is generated. Next, the circuit 5 ignites the switch elements 2a, 2c and current flows from coils 3a-3c to a capacitor 4 via a contact point F. After that, the switch elements 2d, 2f are ignited, the points C-E become at low voltage and current flows from the point F to the capacitor 4. A high frequency magnetic field can be generated by igniting the module 2 at high speed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inverter circuit for driving a coil which generates a magnetic field.

[0002]

2. Description of the Related Art Two conventional inverter circuits will be described. FIG. 5 shows an inverter circuit that generates a rotating magnetic field. Switch element module 51
Is a collector 52a of a certain semiconductor switching element 52 and a certain semiconductor switching element 5 so that three-phase full-wave driving is possible.
Three emitters 53b are connected, and three of these are connected in parallel. The power supply circuit 54 includes a rectifying element 55 and a smoothing capacitor 5.
6 is built in, and the first terminal 51c and the second terminal 5 of the switch element module 51 are rectified and smoothed by a commercial power source.
It is applied to 1d. In the motor 57, the coil 57a is connected in a three-phase Y shape, and its terminal 57b is connected to the connection point of the collector 51a and the emitter 51b of the switch element module 51. The control circuit 58 connects the output terminal 58a to each gate 51e of the switch element module 51.

With the above configuration, the switch element module 51 which applies a voltage obtained by rectifying and smoothing a commercial power source
Ignites each element by a signal from the control circuit 58, supplies a voltage to the coil 57a of the motor 57, generates a magnetic field by the current flowing in the coil 57a, and torques a rotor (not shown) to which a magnet is attached. Is given to rotate. Since the signal of the control circuit 58 sequentially fires the semiconductor switching elements, the coil 57a generates a rotating magnetic field by switching the place where the magnetic field is generated one after another.
As a result, torque (driving force) is supplied to the rotor.

FIG. 6 is an inverter circuit diagram for generating a high frequency magnetic field. The first semiconductor switching element 61 and the second semiconductor switching element 62 are the first semiconductor switching element 61.
The collector 61a is connected to the emitter 62b of the second semiconductor switch element 62. The power supply circuit 63 has a rectifying element 64 and a smoothing capacitor 65 built-in, and rectifies and smoothes a commercial power source to make the emitter 61b of the first semiconductor switching element 61 and the collector 6 of the second semiconductor switching element 62.
It is applied to 2a. The coil 66 has one end connected to the collector 61a of the first semiconductor switching element 61, the other end connected to the resonance capacitor 67, and the other end of the resonance capacitor 67 connected to the emitter 61b of the first semiconductor switching element 61. There is. The control circuit 68 connects the output terminal 68a to the first semiconductor switch element 61 and the second semiconductor switch element 6
2 to each of the gates 61c and 62c.

With the above configuration, the first and second semiconductor switch elements 61 and 62, to which the voltage obtained by rectifying and smoothing the commercial power source is applied, are connected to the first semiconductor switch element 61 and the second semiconductor switch element 61 by the signal of the control circuit 68. Second semiconductor switch element 6
2 are alternately ignited, a voltage is supplied to the series circuit of the coil 66 and the resonance capacitor 67 to oscillate at high frequency, and the coil 6
A high-frequency magnetic field is generated by the current flowing through 6. By this, the magnetic material placed near the coil 66 is heated by induction.

[0006]

However, the above-mentioned 2
The characteristics of the coils of the two inverter circuits (number of turns, wire diameter, connection configuration, etc.) are dedicated to driving force and heating, and these are combined into one inverter circuit and an inverter circuit that performs driving force and heating with a coil. There wasn't. Therefore,
For example, in a conventional induction cooker, heating the stew in the pan placed on the cooker will cause the inside of the pan to stick, so to prevent this, the stew must be stirred occasionally. Instead, it was time-consuming.

The present invention solves such a problem. Since the frequency of the flowing current is controlled only by switching the ignition method of the semiconductor switch by sharing the coil during rotation and heating, the number of parts is reduced. The first purpose is to reduce the cost.

A second object is to keep the total cost of the switch element module low.

A third object is to be applicable to a system for limiting a magnetic field such as partial heating.

A fourth object is to reduce the number of parts and reduce the cost because the frequency of the flowing current is controlled only by switching the ignition method of the semiconductor switch by sharing the coil for rotation and heating. To do.

[0011]

SUMMARY OF THE INVENTION The present invention is to solve the above problems, and a first means for solving the first object is a power supply circuit for rectifying and smoothing a commercial power supply, and a semiconductor switch. A switch element module in which elements are combined, a coil connected in a three-phase Y-shape, at least two resonant capacitors connected in series that resonate with the coil, and a control circuit for firing the semiconductor switch element, A configuration in which an output of a power supply circuit is connected to the switch element module and the resonance capacitor, an output of the switch element module is connected to the coil, and a Y-shaped connection point of the coil and a series connection point of the resonance capacitor are connected. To provide an inverter circuit.

A second object of the present invention to solve the second object of the present invention.
The means is a power supply circuit for rectifying and smoothing a commercial power supply, a first switch element module and a second switch element module in which semiconductor switch elements are combined, and a three-phase Y
A coil connected to the mold, at least two resonant capacitors connected in series that resonate with the coil, and a control circuit that fires the first and second semiconductor switch elements, and the output of the power supply circuit is First and second switching element modules are connected to the resonance capacitor, outputs of the first and second switching element modules are connected to the coil, and a Y-shaped connection point of the coil and the resonance capacitor are connected in series. An inverter circuit having a configuration in which points are connected.

A third object of the present invention to solve the third object of the present invention.
Means for rectifying a commercial power source and smoothing it with at least two smoothing capacitors connected in series, a first switch element module in which semiconductor switch elements are combined, and a second switch element module; A phase Y-type connected coil, at least three resonance capacitors that resonate with the coil, and a control circuit that fires the first and second semiconductor switching elements, and the output of the power supply circuit is the first Connecting to one and a second switch element module, connecting the output of the first and second switch element modules to the coil, connecting one end of each of the resonant capacitors to the second switch element module, Provided is an inverter circuit having a configuration in which the other end of each resonance capacitor is connected to the coil terminal.

A fourth object to solve the fourth object of the present invention.
Means for rectifying and smoothing a commercial power source, a switch element module in which semiconductor switch elements are combined, a coil connected in a three-phase Y-shape, at least three resonance capacitors resonating with the coil, and A control circuit for igniting a semiconductor switch element, the output of the power supply circuit is connected to the switch element module, the output of the switch element module is connected to the coil, and both ends of the resonant capacitor are terminals of the coil. And an inverter circuit configured to form a resonance circuit.

[0015]

By using the above means, when the rotating magnetic field is generated in the coil in the first means, the control circuit sequentially fires the semiconductor switching elements so that the coil receives the DC voltage output from the power supply circuit. Are sequentially switched and applied, the direction of the current flowing through each coil is switched and a rotating magnetic field is generated.

Since the switching frequency of the current flowing through the coil is set sufficiently lower than the resonance frequency formed by the resonance capacitor and the coil, the impedance is high and the current forming the rotating magnetic field is not affected.

When a high-frequency magnetic field is generated in the coil so as to perform induction heating, the control circuit combines the semiconductor switch element whose output of the switch element module is high voltage and the semiconductor switch whose output is low voltage, alternately and at high speed. When ignited, a coil and a resonance capacitor form a resonance circuit, and a high-frequency magnetic field is generated based on the high-frequency current flowing in each coil.

In the second means, when the rotating magnetic field is generated in the coil, the control circuit sequentially fires the semiconductor switches of the first switch element module, so that the DC voltage output from the power supply circuit is sequentially applied to the coil. Since they are switched and applied, the direction of the current flowing through each coil is switched and a rotating magnetic field is generated. At this time, the second switch element module is stopped.

Since the switching frequency of the current flowing through the coil is set sufficiently lower than the resonance frequency formed by the resonance capacitor and the coil, the impedance is high and the current forming the rotating magnetic field is not affected.

When a high frequency magnetic field is generated in the coil so as to perform induction heating, the control circuit alternately ignites the semiconductor switches of the second switch element module at high speed, so that the coil and the resonance capacitor form the resonance circuit. And a high-frequency magnetic field is generated based on the high-frequency current flowing in each coil. At this time, the first switch element module is stopped.

In the third means, when the rotating magnetic field is generated in the coil, the control circuit sequentially fires the semiconductor switches of the first switch element module, so that the DC voltage output from the power supply circuit is sequentially applied to the coil. Since they are switched and applied, the direction of the current flowing through each coil is switched and a rotating magnetic field is generated. At this time, the second switch element module is stopped.

When a high frequency magnetic field is generated in the coil so as to perform induction heating, the control circuit alternately ignites the semiconductor switches of the second switch element module at high speed, so that the coil and the resonance capacitor form a resonance circuit. And a high-frequency magnetic field is generated based on the high-frequency current flowing in each coil. At this time, the first switch element module is stopped.

In the fourth means, when the rotating magnetic field is generated in the coil, the control circuit sequentially fires the semiconductor switching elements, so that the DC voltage output from the power supply circuit is sequentially switched and applied to the coil. , The direction of the current flowing through each coil is switched to generate a rotating magnetic field.

Since the switching frequency of the current flowing through the coil is set sufficiently lower than the resonance frequency formed by the resonance capacitor and the coil, the impedance is high and does not affect the current forming the rotating magnetic field.

When a high-frequency magnetic field is generated in the coil so as to perform induction heating, the control circuit combines the semiconductor switch element whose output of the switch element module is high voltage and the semiconductor switch whose output is low voltage, alternately and at high speed. When ignited, a coil and a resonance capacitor form a resonance circuit, and a high-frequency magnetic field is generated based on the high-frequency current flowing in each coil.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment according to the present invention will be described with reference to FIG. The inverter circuit is composed of a power supply circuit 1 for rectifying and smoothing a commercial power supply, a switch element module 2 in which six semiconductor switch elements 2a to 2f are formed in a three-phase structure as a half bridge, and a three-phase Y type. With the connected coil 3,
It has two resonant capacitors 4a and 4b connected in series and a control circuit 5 for firing the semiconductor switch elements 2a to 2f, and outputs the output of the power supply circuit 1 to the switch element module A,
Connect to the B point and both ends of the resonance capacitor 4 connected in series, connect the outputs C, D and E points of the switch element module 2 to the coil 3, and connect the Y type connection point F of the coil 3 and the resonance capacitor 4 in series. The point G is connected.

First, the operation of generating a rotating magnetic field will be described. A DC voltage is applied to points A and B of the switch element module 2. The control circuit 5 sequentially ignites the switch element modules 2, but first ignites the semiconductor switch elements 2a and 2e. Then, the point C becomes a high voltage and the point D becomes a low voltage, and a current flows from the coils 3a to 3b. A magnetic field is generated by this current, and torque is applied to, for example, a rotor (not shown). Next, the control circuit 3
Ignites the semiconductor switch elements 2c and 2e. Then E
Point becomes a high voltage and point D becomes a low voltage.
An electric current flows toward b. This electric current generates a magnetic field from a place different from the previous one and gives torque to the rotor. In this way, the control circuit 5 sequentially fires the semiconductor switching elements, whereby the location of the magnetic field is switched, so that the rotating magnetic field is generated.

Next, the operation of generating a high frequency magnetic field will be described. The control circuit 5 first detects the semiconductor switch element 2a.
Ignition ~ 2c. Then, points C, D, and E become high voltage, current flows from the coils 3a to 3c toward the Y-shaped connection point F, and this current flows through the resonance capacitor 4.
Next, the control circuit 5 fires the semiconductor switch elements 2d to 2f. Then, points C, D, and E become low voltage, and current flows from the Y-shaped connection point F to the coils 3a to 3c through the resonance capacitor 4. A high-frequency magnetic field can be generated by igniting the semiconductor switching element 2 at high speed. As described above, the rotating magnetic field and the high frequency magnetic field can be generated by sharing the coil 3.

A second embodiment according to the present invention will be described with reference to FIG. The inverter circuit includes a power supply circuit 1 for rectifying and smoothing a commercial power supply, and six semiconductor switch elements 2a to 2f.
Is a half-bridge and has a three-phase first switching element module 2 as shown in FIG. 2, and two semiconductor switching elements 6g and 6h are half-bridges and has a second switching element module 6 as shown in FIG. , A coil 3 connected in a three-phase Y-shape, and two resonance capacitors 4 connected in series
a, 4b and the semiconductor switch elements 2a to 2f, 6g, 6
It has a control circuit 5 for firing h, and outputs the output of the power supply circuit 1 to the A and B points of the first switch element module, the H and I points of the second switch element module, and the resonance capacitor 4 connected in series. Connected to both ends, the outputs C, D and E of the first switch element module 2 and the output J point of the second switch element module 6 are connected to the coil 3 via the diode 7, and the Y-type connection of the coil 3 is made. The point F and the series connection point G of the resonance capacitor 4 are connected.

First, the operation of generating a rotating magnetic field will be described. A DC voltage is applied to points A and B of the first switch element module 2. The control circuit 5 sequentially fires the first switch element module 2, but first fires the semiconductor switch elements 2a and 2e. Then, the point C becomes a high voltage and the point D becomes a low voltage, and a current flows from the coils 3a to 3b. A magnetic field is generated by this current, and torque is applied to, for example, a rotor (not shown). Next, the control circuit 3 fires the semiconductor switch elements 2c and 2e. Then, the point E becomes a high voltage and the point D becomes a low voltage, and a current flows from the coils 3c to 3b. This electric current generates a magnetic field from a place different from the previous one and gives torque to the rotor.

As the control circuit 5 sequentially fires the semiconductor switching elements in this way, the location of the magnetic field is switched, so that a rotating magnetic field is generated. The control circuit 5 does not ignite the second switch element module 6 when the rotating magnetic field is generated.

Next, the operation of generating a high frequency magnetic field will be described. First, the control circuit 5 includes a semiconductor switch element 6g.
Fire. Then, the point J becomes a high voltage, and the coil 3a-
A current flows from 3c toward the Y-shaped connection point F, and this current flows through the resonance capacitor 4. Next, the control circuit 5
Ignites the semiconductor switch element 6h. Then, the point J becomes a low voltage, and a current flows from the Y-shaped connection point F to the coils 3a to 3c through the resonance capacitor 4.

A high frequency magnetic field can be generated by igniting the second switch element module 6 at high speed. The control circuit 5 does not ignite the first switch element module 2 when a high frequency magnetic field is generated. As described above, the rotating magnetic field and the high frequency magnetic field can be generated by sharing the coil 3.

A third embodiment according to the present invention will be described with reference to FIG. The inverter circuit includes a power supply circuit 1 that rectifies a commercial power supply and smoothes it with at least two smoothing capacitors 7 connected in series, and six semiconductor switch elements 2a to 2a.
f is a half bridge and the first switching element module 2 is configured in three phases as shown in FIG. 3, and the two semiconductor switching elements 6g and 6h are half bridges and the second switching element module is configured as shown in FIG. 6, a coil 3 connected in a three-phase Y-shape, and three resonance capacitors 4a, 4b, 4
c, and a control circuit 5 for igniting the semiconductor switch elements 2a to 2f, 6g, 6h, and the output of the power supply circuit 1 is at points A and B of the first switch element module and H of the second switch element module. , I point, and outputs C, D, E points of the first switching element module 2 and the resonance capacitor 4
One ends of a, 4b, and 4c are connected to the coil 3, and the other ends of the resonance capacitors 4a, 4b, and 4c are connected to the point J of the second switch element module 6. The Y-shaped connection point F of the coil 3 is connected to the series connection point K of the smoothing capacitor 7.

First, the operation of generating a rotating magnetic field will be described. A DC voltage is applied to points A and B of the first switch element module 2. The control circuit 5 sequentially fires the first switch element module 2, but first fires the semiconductor switch elements 2a and 2e. Then, the point C becomes a high voltage and the point D becomes a low voltage, and a current flows from the coils 3a to 3b. A magnetic field is generated by this current, and torque is applied to, for example, a rotor (not shown). Next, the control circuit 3 fires the semiconductor switch elements 2c and 2e. Then, the point E becomes a high voltage and the point D becomes a low voltage, and a current flows from the coils 3c to 3b. This electric current generates a magnetic field from a place different from the previous one and gives torque to the rotor.

As the control circuit 5 sequentially fires the semiconductor switching elements in this way, the magnetic field generation location is switched, so that a rotating magnetic field is generated. The control circuit 5 does not ignite the second switch element module 6 when the rotating magnetic field is generated.

Next, the operation of generating a high frequency magnetic field will be described. First, the control circuit 5 includes a semiconductor switch element 6g.
Fire. Then, the point J becomes a high voltage, and a current flows from the resonance capacitor 4 to the smoothing capacitor 7 from the coils 3a to 3c through the Y-type connection point F. Next, the control circuit 5 fires the semiconductor switch element 6h. Then, the point J becomes a low voltage, and a current flows from the Y-shaped connection point F through the smoothing capacitor 7 to the resonance capacitor 4 through the coils 3a to 3c. Second switch element module 6
A high-frequency magnetic field can be generated by rapidly igniting the. As described above, the rotating magnetic field and the high frequency magnetic field can be generated by sharing the coil 3.

A fourth embodiment will be described with reference to FIG. The inverter circuit is a power supply circuit 1 that rectifies and smoothes commercial power.
A switch element module 2 in which six semiconductor switch elements 2a to 2f are half-bridges configured in three phases as shown in FIG. 4, a three-phase Y-type connected coil 3, and three Δ-type connected resonances. It has capacitors 4a, 4b, 4c and a control circuit 5 for firing the semiconductor switch elements 2a to 2f, and connects the output of the power supply circuit 1 to points A and B of the switch element module to output C of the switch element module 2. , D, E points are Δ connection points L, M of the coil 3 and the resonance capacitor 4,
Connected to N.

First, the operation of generating a rotating magnetic field will be described. A DC voltage is applied to points A and B of the switch element module 2. The control circuit 5 sequentially ignites the switch element modules 2, but first ignites the semiconductor switch elements 2a and 2e. Then, the point C becomes a high voltage and the point D becomes a low voltage, and a current flows from the coils 3a to 3b. A magnetic field is generated by this current, and torque is applied to, for example, a rotor (not shown). Next, the control circuit 3
Ignites the semiconductor switch elements 2c and 2e. Then E
Point becomes a high voltage and point D becomes a low voltage.
An electric current flows toward b. This electric current generates a magnetic field from a place different from the previous one and gives torque to the rotor. In this way, the control circuit 5 sequentially fires the semiconductor switching elements, whereby the location of the magnetic field is switched, so that the rotating magnetic field is generated.

Next, the operation of generating a high frequency magnetic field will be described. The control circuit 5 first detects the semiconductor switch element 2a.
And 2e are ignited. Then, the point C becomes a high voltage and the point D becomes a low voltage, and a current flows through the coils 3 a to 3 b and the resonance capacitor 4. Next, the control circuit 5 fires the semiconductor switch elements 2b and 2d. Then point C is low voltage, D
The point becomes a high voltage, and the resonance capacitor 4 and the coil 3b
A current flows from 3 to 3a. A high-frequency magnetic field can be generated by igniting the semiconductor switching element 2 at high speed. As described above, the rotating magnetic field and the high frequency magnetic field can be generated by sharing the coil 3.

[0041]

INDUSTRIAL APPLICABILITY The present invention shares a coil for generating a rotating magnetic field and a coil for generating a high frequency magnetic field for performing induction heating. For example, when applied to a cooker, a stewed food placed in a pan It can be heated and agitated, and it eliminates burning and saves labor.

Further, the inverter circuit has the following effects. According to the first means, the frequency of the flowing current is controlled only by switching the ignition method of the semiconductor switch by sharing the coil during rotation and during heating, so that the number of parts can be reduced and the cost can be reduced. .

According to the second means, although the number of the six semiconductor switch elements constituting the first switch element module is large by utilizing the difference in the frequency of the current flowing through the coil during rotation and during heating, the number is low. The cost is low for high frequencies, and the semiconductor switch elements forming the second switch module are for high frequencies and are high in cost but few in number. Therefore, the overall cost of the switch element module can be kept low.

According to the third means, in addition to the second means,
Three sets of resonance circuits will be configured during heating,
Of these, the resonance frequency can be individually changed by changing the capacitance of the resonance capacitor, so that the high-frequency magnetic field can be freely generated. Therefore, it can be applied to a system that limits the magnetic field such as partial heating.

According to the fourth means, the frequency of the flowing current is controlled only by switching the ignition method of the semiconductor switch by sharing the coil during rotation and the coil during heating, so that the number of parts is reduced and the cost is reduced. You can

[Brief description of drawings]

FIG. 1 is an inverter circuit diagram according to a first embodiment of the present invention.

FIG. 2 is an inverter circuit diagram according to a second embodiment of the present invention.

FIG. 3 is an inverter circuit diagram according to a third embodiment of the present invention.

FIG. 4 is an inverter circuit diagram according to a fourth embodiment of the present invention.

FIG. 5 is a first inverter circuit diagram according to a conventional example.

FIG. 6 is a second inverter circuit diagram according to a conventional example.

[Explanation of symbols]

 1 Power Supply Circuit 2 (First) Switch Element Module 3 Coil 4 Resonant Capacitor 5 Control Circuit 6 Second Switch Element Module 7 Smoothing Capacitor

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsunori Zaimae 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. (72) Kazuhiko Asada, 1006 Kadoma, Kadoma City, Osaka Matsushita Electric Industrial Co., Ltd. 72) Inventor Hideki Omori 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (4)

[Claims] 1. A power supply circuit for rectifying and smoothing a commercial power supply,
A switch element module including a combination of semiconductor switch elements, a coil connected in a three-phase Y-shape, at least two series-connected resonant capacitors that resonate with the coil, and a control circuit for firing the semiconductor switch element are provided. Connecting the output of the power supply circuit to the switch element module and the resonance capacitor, connecting the output of the switch element module to the coil, and connecting the Y-shaped connection point of the coil and the series connection point of the resonance capacitor. Inverter circuit with the above configuration. 2. A power supply circuit for rectifying and smoothing a commercial power supply,
A first switch element module and a second switch element module in which semiconductor switch elements are combined, a coil connected in a three-phase Y shape, at least two series-connected resonant capacitors that resonate with the coil, and the first switch element module. And a control circuit for igniting a second semiconductor switching element, the output of the power supply circuit is connected to the first and second switching element modules and the resonant capacitor, the first and second switching element An inverter circuit having a configuration in which an output of a module is connected to the coil, and a Y-shaped connection point of the coil and a series connection point of the resonance capacitor are connected. 3. A power supply circuit for rectifying a commercial power supply and smoothing it with at least two smoothing capacitors connected in series,
A first switch element module in which semiconductor switch elements are combined, and a second switch element module,
A coil connected in a three-phase Y-shape, at least three resonant capacitors that resonate with the coil, and a control circuit that fires the first and second semiconductor switch elements, and the output of the power supply circuit is Connected to the first and second switch element module, the output of the first and second switch element module is connected to the coil, one end of each resonant capacitor is connected to the second switch element module, An inverter circuit having a configuration in which the other end of each of the resonance capacitors is connected to the coil terminal, and a Y-shaped connection point of the coil and a series connection point of the smoothing capacitor are connected. 4. A power supply circuit for rectifying and smoothing a commercial power supply,
A switch element module including a combination of semiconductor switch elements, a coil connected in a three-phase Y-shape, at least three resonance capacitors that resonate with the coil, and a control circuit that ignites the semiconductor switch element. An inverter circuit in which an output of a circuit is connected to the switch element module, an output of the switch element module is connected to the coil, and both ends of the resonance capacitor are connected to terminals of the coil to form a resonance circuit.