JP2019103147A - Power converter - Google Patents

Abstract

To provide a power converter which can reduce switching elements for boosting.SOLUTION: A power converter has at least a single switching element and converts power from a main power supply by a switching operation of the switching element. The power converter has a boosting circuit boosting by the switching operation of the switching element, a first capacitor charged by boosted voltage, a second capacitor generating negative voltage by charging electric charge discharged from the first capacitor in a charge state by the switching operation, a conducting drive circuit controlling the switching element into a conduction state by applying the boosted voltage to a control terminal of the switching element, and an intercepting drive circuit controlling the switching element into an interception state by applying the negative voltage to the control terminal of the switching element by discharging the second capacitor of the charged state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power converter.

  Conventionally, a power converter such as an inverter or converter is configured of a switching leg in which a switching element for the upper arm and a switching element for the lower arm are connected in series, and a gate drive circuit for driving the switching leg. The gate drive circuit can convert DC power into AC power by controlling on / off of each switching element of the switching leg.

  Incidentally, in Patent Document 1, a drive voltage for driving the lower-arm switching element is boosted using a step-up chopper circuit, and a gate drive is used to use the boosted voltage as a drive voltage for driving the upper-arm switching element. A circuit is disclosed. The boosting chopper circuit includes an inductor and a MOSFET, and performs boosting by releasing energy stored in the inductor by turning on and off the MOSFET.

Japanese Patent Application Laid-Open No. 2003-18821

  However, when the gate drive circuit described in Patent Document 1 is used for the power converter, in addition to the switching element of the switching leg that converts DC power into AC power, a switching element (MOSFET) for a boost chopper circuit is required. Become expensive.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a power converter capable of reducing switching devices for boosting.

  One embodiment of the present invention is a power converter including at least one switching element and converting power from a main power source by a switching operation of the switching element, wherein the boosting circuit boosts by the switching operation; A second capacitor that generates a negative voltage by charging a first capacitor charged by a second voltage, a second capacitor that generates a negative voltage by charging the charge discharged from the first capacitor in a charged state by the switching operation, and the boosted voltage A conduction drive circuit for controlling the switching element to a conductive state by applying the voltage to the control terminal of the switching element, and discharging the second capacitor in a charged state to the control terminal of the switching element so as to cause the negative voltage A cutoff drive circuit that controls the switching element into a cutoff state by applying A power converter according to claim Rukoto.

  One embodiment of the present invention is the power converter described above, wherein the booster circuit includes an inductor, a third capacitor connected to one end of the inductor, and a fourth connected to the other end of the inductor. A first charging circuit for charging the fourth capacitor by the capacitor, the electromotive voltage generated in the inductor when the switching element is switched from the conductive state to the disconnected state, and the voltage by which the third capacitor is charged And further comprising

  One embodiment of the present invention is the power converter described above, wherein one end of the first capacitor is connected to the other end of the inductor, and the other end is connected to one end of a second capacitor, The drive circuit electrically connects one end of the first capacitor in the charged state and the other end of the second capacitor by controlling the switching element to a conductive state to charge the second capacitor. Form a second charging circuit.

  One embodiment of the present invention is the power converter described above, wherein the drive circuit for conduction is charged in the fourth capacitor by connecting the fourth capacitor and the control terminal of the switching element. Voltage is applied to the control terminal, and the disconnecting drive circuit applies the negative voltage to the control terminal by connecting one end of the second capacitor to the control terminal.

  One embodiment of the present invention is the power converter described above, wherein the booster circuit supplies the charge discharged from the third capacitor to the inductor through a path passing through the switching element in a conductive state. And the energy storage circuit for storing energy in the inductor.

  One embodiment of the present invention is the power converter described above, wherein the switching element includes a switching leg in which a semiconductor switching element for the upper arm and a semiconductor switching element for the lower arm are connected in series, the switching element Is a semiconductor switching element for the upper arm.

  As described above, according to the present invention, it is possible to reduce the switching element for boosting.

It is a circuit diagram of power converter 1 concerning one embodiment of the present invention. FIG. 10 is an explanatory view showing a flow of operation of the upper arm drive circuit 6a in the operation mode 1 according to the embodiment of the present invention. FIG. 14 is an explanatory view showing a flow of operation of the upper arm drive circuit 6a in the operation mode 2 according to one embodiment of the present invention. FIG. 14 is an explanatory view showing a flow of operation of the upper arm drive circuit 6 a in the operation mode 3 according to the embodiment of the present invention.

Hereinafter, a power converter 1 according to an embodiment of the present invention will be described.
FIG. 1 is a circuit diagram of a power converter 1 according to an embodiment of the present invention. For example, the power converter 1 is an inverter, a DC-DC converter, or a motor drive circuit.

  As shown in FIG. 1, the power converter 1 includes switching elements 2 and 3 (semiconductor switching elements), a load driving power supply 4, a semiconductor switching element driving circuit 6, and a control signal generating unit 7.

  The switching element 2 is a semiconductor switching element for the upper arm connected between the load driving power supply 4 and the ground. For example, the switching element 2 is a switching element of a wide gap semiconductor such as MOSFET (metal-oxide-semiconductor field-effect transistor), IGBT (insulated gate bipolar transistor), SiC (silicon carbide) or GaN (gallium nitride). . In the present embodiment, a case where the switching element 2 is an n-type MOSFET will be described.

  The switching element 3 is a semiconductor switching element for the lower arm connected between the load driving power supply 4 and the ground. For example, the switching element 3 is a MOSFET, an IGBT, or a switching element of a wide gap semiconductor such as SiC or GaN. In the present embodiment, a case where the switching element 3 is an n-type MOSFET will be described. Such a pair of switching elements 2 and 3 are connected in series with each other to constitute a switching leg.

The drain terminal (input terminal) of the switching element 2 is connected to the load driving power supply 4. The source terminal (output terminal) of the switching element 2 is connected to the drain terminal of the switching element 3. The source terminal of the switching element 3 is connected to the ground.
The gate terminals (control terminals) of the switching elements 2 and 3 are connected to the semiconductor switching element drive circuit 6.
The switching elements 2 and 3 are turned on or off based on the gate voltage supplied from the semiconductor switching element drive circuit 6. Thereby, the switching elements 2 and 3 convert the input voltage Vin supplied from the load driving power supply 4 into an alternating voltage and output the alternating voltage to the load. That is, the power converter 1 converts the power from the load driving power source 4 which is the main power source by the switching operation of the switching elements 2 and 3 and outputs the power to the load.

  The load driving power supply 4 is a supply source of power supplied from the power converter 1 to the load. The output terminal of the load driving power supply 4 is connected to the drain terminal of the switching element 2. Therefore, the input voltage Vin supplied from the load driving power supply 4 is supplied to the drain terminal of the switching element 2.

  The control power supply 5 is a control power supply of positive polarity. For example, the control power supply 5 may be a power supply for driving the switching elements 2 and 3 or may be a power supply for driving another device (not shown). For example, the control power supply 5 is a power supply for a microcomputer and has a low voltage. The voltage of the control power supply 5 is a voltage VDD.

The semiconductor switching element drive circuit 6 boosts the voltage VDD from the control power source 5 which is a single power source, and outputs the boosted voltage to the gate terminals of the switching elements 2 and 3 as the gate voltage. Thus, the semiconductor switching element drive circuit 6 can control each of the switching elements 2 and 3 to be on (conductive state).
Further, the semiconductor switching element drive circuit 6 generates a negative power supply from the boosted voltage, and outputs the generated negative power supply to the gate terminals of the switching elements 2 and 3 as a gate voltage. Thereby, the semiconductor switching element drive circuit 6 can control each of the switching elements 2 and 3 to be off (cut off state).

  The semiconductor switching element drive circuit 6 includes an upper arm drive circuit 6a and a lower arm drive circuit 6b.

The upper arm drive circuit 6 a controls on / off of the switching element 2 as the upper arm based on the voltage VDD from the control power supply 5. Specifically, the upper arm drive circuit 6a boosts the voltage VDD and applies the boosted voltage to the gate terminal of the switching element 2 in order to sufficiently turn on the switching element 2 of the upper arm.
Further, the upper arm drive circuit 6 a generates a negative voltage from the boosted voltage and applies the generated negative voltage to the gate terminal of the switching element 2 in order to sufficiently turn off the switching element 2 which is the upper arm. .

The lower arm drive circuit 6 b controls on / off of the switching element 3 which is the lower arm based on the voltage VDD from the control power supply 5. Specifically, the lower arm drive circuit 6 b boosts the voltage VDD and applies the boosted voltage to the gate terminal of the switching element 3 in order to sufficiently turn on the switching element 3 which is the lower arm.
The lower arm drive circuit 6b generates a negative voltage from the boosted voltage and applies the generated negative voltage to the gate terminal of the switching element 3 in order to sufficiently turn off the switching element 3 which is the lower arm. .

  The control signal generator 7 is connected to each of the upper arm drive circuit 6a and the lower arm drive circuit 6b. The control signal generator 7 outputs a control signal instructing generation of the gate voltage to each of the upper arm drive circuit 6a and the lower arm drive circuit 6b. The control signal is, for example, a pulse width modulation (PWM) signal.

  Below, the structure of the drive circuit 6a for upper arms which concerns on one Embodiment of this invention, and the drive circuit 6b for lower arms is demonstrated concretely.

  The upper arm drive circuit 6 a includes a backflow preventing diode 8, a boosting capacitor 9 (third capacitor), an inductor 10, a backflow preventing diode 11, a reverse flow preventing diode 12, and a negative power supply buffer capacitor 13 (first And a smoothing capacitor 14 (fourth capacitor), a charge / discharge control unit 15, a rectifying diode 16, a backflow preventing diode 17, and a negative power supply capacitor 18 (second capacitor). The boosting capacitor 9, the inductor 10, the backflow preventing diode 12, the smoothing capacitor 14, and the switching element 2 constitute a boosting circuit.

  The anode of the backflow prevention diode 8 is connected to the positive terminal of the control power supply 5, and the cathode is connected to one end of the boosting capacitor 9.

  One end of the boosting capacitor 9 is connected to one end of the inductor, and the other end is connected to the source terminal of the switching element 2.

  One end of the inductor 10 is connected to the cathode of the backflow prevention diode 8, and the other end is connected to one end of the negative power supply buffer capacitor 13.

  The anode of the backflow prevention diode 11 is connected to the other end of the inductor 10, and the cathode is connected to the drain terminal of the switching element 2.

  The anode of the backflow prevention diode 12 is connected to the other end of the inductor 10, and the cathode is connected to one end of the smoothing capacitor 14.

  One end of the negative power supply buffer capacitor 13 is connected to the other end of the inductor 10 and the cathodes of the backflow preventing diodes 11 and 12. The other end of the negative power supply buffer capacitor 13 is connected to the cathode of the rectifying diode 16 and the anode of the reverse current preventing diode 17.

  One end of the smoothing capacitor 14 is connected to the charge / discharge control unit 15, and the other end is connected to the source terminal of the switching element 2.

  The charge / discharge control unit 15 controls the charge / discharge of the boosting capacitor 9, the negative power supply buffer capacitor 13, the smoothing capacitor 14, and the negative power supply capacitor 18 based on the control signal output from the control signal generation unit 7. Do. The configuration of the charge / discharge control unit 15 will be specifically described below.

  The charge / discharge control unit 15 includes a switching element 151 (drive circuit for conduction) and a switching element 152 (drive circuit for cutoff).

  The switching element 151 supplies a drive signal for conduction to the gate terminal of the switching element 2. The conduction drive signal is a signal for turning on the switching element 151, and is, for example, a voltage (gate voltage) boosted by a booster circuit. For example, the switching element 151 is an NPN IGBT.

  The switching element 152 supplies a blocking drive signal to the gate terminal of the switching element 2. The blocking drive signal is a signal for turning off the switching element 151, and is, for example, a negative voltage (gate voltage). For example, the switching element 152 is a PNP IGBT.

  The collector terminal of the switching element 151 is connected to one end of the smoothing capacitor and the cathode of the backflow preventing diode 12. The emitter terminal of the switching element 151 is connected to the emitter terminal of the switching element 152. The base terminal of the switching element 151 and the base terminal of the switching element 152 are connected to the control signal generator 7. The connection point between the emitter terminal of the switching element 151 and the emitter terminal of the switching element 152 is connected to the gate terminal of the switching element 2. The collector terminal of the switching element 152 is connected to one end of the negative power supply capacitor 18.

  In the present embodiment, the charge / discharge control unit 15 is a push-pull circuit using the switching element 151 and the switching element 152. However, the present invention is not limited to this. The control circuit controls on / off of the switching element 2 There is no particular limitation as long as it is.

  The anode of the rectifying diode 16 is connected to the collector terminal of the switching element 152, and the cathode is connected to the other end of the negative power supply buffer capacitor 13.

  The anode of the backflow prevention diode 17 is connected to the other end of the negative power supply buffer capacitor 13, and the cathode is connected to the source terminal of the switching element 2.

  One end of the negative power supply capacitor 18 is connected to the anode of the rectifying diode 16 and the collector terminal of the switching element 152. The other end of the negative power supply capacitor 18 is connected to the other end of the boosting capacitor 9, the source terminal of the switching element 2, and the drain terminal of the switching element 3.

  The lower arm drive circuit 6b has the same configuration as the upper arm drive circuit 6a. For convenience of explanation, the configuration of upper arm drive circuit 6a (backflow prevention diode 8, boosting capacitor 9, inductor 10, backflow prevention diode 11, reverse flow prevention diode 12, negative power supply buffer capacitor 13, smoothing) Each of the reference numerals of the capacitor 14, the charge / discharge control unit 15, the rectifying diode 16, the backflow preventing diode 17, and the negative power supply capacitor 18) is suffixed with a, and each of the configurations of the lower arm driving circuit 6b Add b at the end.

  Next, the flow of the operation of the upper arm drive circuit 6a according to one embodiment of the present invention will be described with reference to FIGS. In the present embodiment, three operation modes are provided as the operation modes of the upper arm drive circuit 6a, and the upper arm drive circuit 6a is: operation mode 1 → operation mode 2 → operation mode 3 → operation mode 2 → operation mode 1 The switching element 2 is controlled to be turned on or off by switching the operation mode in the order of. In FIGS. 2 to 4, switching elements 2, 3, 151 and 152 indicated by broken lines indicate that they are off, and switching elements 2, 3, 151 and 152 indicated by solid lines indicate that they are on. . The operation of the lower arm drive circuit 6b is the same as the operation of the upper arm drive circuit 6a, so the description will be omitted.

<Operation mode 1>
FIG. 2 is an explanatory view showing the flow of the operation of the upper arm drive circuit 6a in the operation mode 1 according to the embodiment of the present invention. As shown in FIG. 2, in the operation mode 1, the switching element 151a is off and the switching element 152a is on. Also, the switching element 151b is on and the switching element 152b is off. For convenience of explanation, it is assumed that the negative power supply capacitor 18a is charged as an initial condition.

  As shown in FIG. 2, the switching element 3 is on. Therefore, the current from the control power supply 5 passes through the backflow preventing diode 8a, the boosting capacitor 9a, the switching element 3 and the path W1 passing through the ground. Therefore, the boosting capacitor 9a is charged by the current passing through the path W1 when the switching element 3 of the lower arm is on.

  Further, the current from the control power supply 5 passes through the reverse flow prevention diode 8a, the inductor 10a, the negative power supply buffer capacitor 13a, the reverse flow prevention diode 17a, the switching element 3 and the path W2 passing through the ground. Therefore, the negative power supply buffer capacitor 13a is charged by the current passing through the path W2 when the switching element 3 of the lower arm is on.

Further, the current from the control power supply 5 passes through the backflow prevention diode 8a, the inductor 10a, the backflow prevention diode 12a, the smoothing capacitor 14a, the switching element 3 and the path W3 passing through the ground. Therefore, smoothing capacitor 14a is charged by the current passing through path W3 when switching element 3 of the lower arm is on.
At this time, the inductor 10 is charged by the current passing through the paths W2, 3.

  In the operation mode 1, since the switching element 152a is turned on, the charge / discharge control unit 15a electrically connects one end of the negative power supply capacitor 18a to the gate terminal of the switching element 2. As a result, the charge that has been charged in the negative power supply capacitor 18a passes through the input capacitance 20 of the switching element 2 and the switching element 152a, and the path W4 that returns to the negative power supply capacitor 18a. In this case, since the charge stored in the input capacitor 20 is discharged, the switching element 2 shifts from on to off. In other words, the negative charge stored in the negative power supply capacitor 18a passes through the switching element 152a and the input capacitor 20 and returns to the other end of the negative power supply capacitor 18a. Therefore, a gate voltage of negative voltage is applied to the gate terminal of the switching element 2. Thereby, the switching element 2 is turned off.

<Operation mode 2>
FIG. 3 is an explanatory view showing the flow of the operation of the upper arm drive circuit 6a in the operation mode 2 according to the embodiment of the present invention. As shown in FIG. 3, in the operation mode 2, the switching element 151 b is turned off and the switching element 152 b is turned on by the control signal from the control signal generation unit 7. Thereby, the switching element 3 is turned off.

As shown in FIG. 3, when the switching element 3 is turned on from the off state, the current I _L flowing through the inductor 10 is reduced, so that an electromotive voltage ΔV is generated in the inductor 10 a. The smoothing capacitor 14a is charged through the path W5 by the electromotive voltage ΔV and the voltage V1 of the boosting capacitor 9a. In other words, the first charging circuit for charging the smoothing capacitor 14a by the electromotive voltage generated in the inductor 10a by the switching element 3 changing from the conductive state to the cut-off state and the voltage V1 charged by the boosting capacitor 9a. Is formed. Here, the voltage V1 is substantially the same as the voltage VDD. Therefore, the smoothing capacitor 14a is charged with the voltage V2 boosted from the voltage VDD by the electromotive voltage ΔV. Further, in this case, the negative power supply buffer capacitor 13a is also boosted to the voltage V2 in the same manner as the smoothing capacitor 14a.

  In the operation mode 2, the switching element 152a is turned on as in the operation mode 1. Therefore, the gate voltage of the negative voltage is applied to the gate terminal of the switching element 2, and the switching element 2 is maintained off.

<Operation mode 3>
FIG. 4 is an explanatory view showing the flow of the operation of the upper arm drive circuit 6a in the operation mode 3 according to the embodiment of the present invention. As shown in FIG. 4, in the operation mode 3, the switching element 151 a is turned on and the switching element 152 a is turned off by the control signal from the control signal generation unit 7.

  As shown in FIG. 4, when the switching element 151 a is turned on and the switching element 152 a is turned off, the charge stored in the smoothing capacitor 14 passes through the switching element 151 and the input capacitance 20 of the switching element 2, The path W6 is returned to the other end of the smoothing capacitor 14. Therefore, the input capacitor 20 starts charging by the charge discharged from the smoothing capacitor 14. When the input capacitance 20 is sufficiently charged in the operation mode 3, the switching element 2 is turned on.

  When the switching element 2 is turned on, the charge stored in the negative power supply buffer capacitor 13a is discharged. Therefore, the charge stored in the negative power supply buffer capacitor 13a passes through the backflow prevention diode 11a, the switching element 2, the negative power supply capacitor 18a, and the rectification diode 16a to the other end of the negative power supply buffer capacitor 13a. Go back path W7. Therefore, the negative power supply capacitor 18a is charged by the charge discharged from the negative power supply buffer capacitor 13a. That is, the other end of the negative power supply capacitor 18a is charged with positive charge, and one end of the negative power supply capacitor 18a is charged with negative charge.

  In other words, in the operation mode 3, when the switching element 3 is turned on, one end of the negative power supply buffer capacitor 13a in a charged state is electrically connected to the other end of the negative power supply capacitor 18a. A second charging circuit is formed to charge capacitor 18a. The second charging circuit charges the negative power supply capacitor 18 a via the switched-on switching element 2. In the present embodiment, the second charging circuit includes the negative power supply buffer capacitor 13a, the backflow prevention diode 11a, the switching element 2, the negative power supply capacitor 18a, and the rectifying diode 16a.

When the switching element 2 is turned on, the charge stored in the boosting capacitor 9 passes through the inductor 10a, the backflow preventing diode 11a, the switching element 2, and the path W8 passing through the ground. That is, the electric charge charged in the step-up capacitor 9, to be discharged through the path W8 passing through the switching element 2, a current I _L flows through the inductor 10a. Thereby, energy is accumulated in the inductor 10a. In other words, when the switching element 2 is shifted to the on state, an energy storage circuit is formed which stores energy in the inductor 10 a by the charge stored in the boosting capacitor 9.

  The energy storage circuit includes at least a boosting capacitor 9, an inductor 10 a and a switching element 2. The energy storage circuit of the present embodiment includes a boosting capacitor 9, an inductor 10a, a backflow preventing diode 11a, and a switching element 2.

As a result, when operating mode 3 shifts to operating mode 2, capacitor for negative power supply 18a discharges the charge that has been charged in operating mode 2, so a negative voltage is generated at the gate terminal of switching element 2. Applied. Thereby, the switching element 2 is turned off. Then, the switching element 2 is turned off, the discharge of the step-up capacitor 9 is stopped, the current I _L flowing through the inductor 10 decreases. As a result, an electromotive voltage ΔV is generated in the inductor 10a, and the voltage VDD is boosted.

  As described above, the power converter 1 according to the present embodiment uses the switching element 2 as a switching element of the booster circuit. Specifically, the power converter 1 generates an electromotive voltage in the inductor 10 by controlling the switching of the switching element 2 to be controlled. Then, the power converter 1 boosts the gate voltage for driving the switching element 2 to a predetermined voltage using the electromotive voltage. Thus, when applying a voltage higher than the voltage VDD of the control power supply 5 to the gate voltage of the switching element 2, it is not necessary to provide a new switch. Therefore, the power converter 1 can reduce the number of switching elements for boosting as compared with the conventional case. Therefore, the drive voltage for the upper arm can be boosted at low cost. Further, the power converter 1 does not have to include a control device that controls the switching of the step-up switching element. Therefore, the increase in size of the power converter 1 can be suppressed, and the cost reduction can be realized.

  In the power converter 1 according to the present embodiment, the negative power supply buffer capacitor 13 charged by the boosted voltage and the charge discharged from the negative power supply buffer capacitor 13 in the charged state by the switching operation of the switching element 2. And a negative power supply capacitor 18 that generates a negative voltage by charging the As a result, when the switching element 2 of the upper arm is reliably turned off, a negative voltage can be generated without adding a new power supply. That is, the power converter 1 can drive both power supplies of the switching element 2 with only one power supply. Therefore, when adopting a device that needs to apply a negative voltage (for example, a GaN device, a SiC device, etc.) or a device that can be driven at high speed by applying a negative voltage as the switching element 2, By applying the upper arm drive circuit 6a, no new power supply is added. Therefore, the cost of the mounted parts can be reduced, the reliability can be improved, and the mounting area can be reduced.

  In the above-described embodiment, the power converter 1 can boost the voltage VDD if the charge stored in the smoothing capacitor 14 is larger than the amount of charge required to charge the input capacitor 20.

  In the above-described embodiment, the power converter 1 boosts even when the operation mode 1 shifts to the operation mode 2, but the negative power supply buffer capacitor 13 and the smoothing capacitor 14 are already charged. Is not boosted even from the operation mode 1 to the operation mode 2. Therefore, when the operation of power converter 1 becomes steady, electric power is charged in capacitor 13 for negative power supply buffer and smoothing capacitor 14, so that power converter 1 operates from the operation mode 2 to the operation mode. Only when shifting to 3, the voltage VDD is boosted.

  The embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and includes design and the like within the scope of the present invention.

  In the above embodiment, a voltage limiter may be provided to limit the voltage across the negative power supply capacitor 18 to a predetermined voltage. The predetermined voltage corresponds to the gate voltage of the negative voltage applied to the gate terminal of the switching element 2. Therefore, the predetermined voltage is set based on the gate voltage when the switching element 2 is turned off and the withstand voltage of the gate terminal of the switching element 2. For example, the voltage limiting unit is a Zener diode, and the breakdown voltage of the Zener diode corresponds to the predetermined voltage.

DESCRIPTION OF SYMBOLS 1 Power converter 2, 3 Switching element 4 Load drive power supply 6 Semiconductor switching element drive circuit 7 Control signal generation part 8 Backflow prevention diode 9 Boosting capacitor (third capacitor)
DESCRIPTION OF SYMBOLS 10 Inductor 11 Backflow prevention diode 12 Backflow prevention diode 13 Negative power supply buffer capacitor (first capacitor)
14 Smoothing capacitor (fourth capacitor)
15 charge / discharge control unit 16 rectifying diode 17 reverse current preventing diode 18 negative power supply capacitor (second capacitor)

Claims (6)

A power converter comprising at least one switching element and converting power from a main power source by switching operation of the switching element, the power converter comprising:
A booster circuit for boosting by the switching operation;
A first capacitor charged by the boosted voltage;
A second capacitor that generates a negative voltage by charging the charge discharged from the first capacitor in a charged state by the switching operation;
A conduction drive circuit for controlling the switching element to a conductive state by applying the boosted voltage to a control terminal of the switching element;
A cutoff drive circuit that applies the negative voltage to the control terminal of the switching element by discharging the second capacitor in a charged state to control the switching element into a cutoff state;
A power converter comprising: The booster circuit is
An inductor,
A third capacitor connected to one end of the inductor;
A fourth capacitor connected to the other end of the inductor;
A first charging circuit for charging the fourth capacitor with the electromotive voltage generated in the inductor when the switching element is switched from the conduction state to the cutoff state, and the voltage at which the third capacitor is charged;
The power converter according to claim 1, further comprising: One end of the first capacitor is connected to the other end of the inductor, and the other end is connected to one end of the second capacitor.
The conduction drive circuit electrically connects one end of the first capacitor in a charged state to the other end of the second capacitor by controlling the switching element to be in a conductive state to thereby connect the second capacitor. A power converter according to claim 2, characterized in that it forms a second charging circuit for charging the capacitor. The conduction drive circuit applies the voltage charged in the fourth capacitor to the control terminal by connecting the fourth capacitor and the control terminal of the switching element.
The power converter according to claim 2, wherein the cutoff drive circuit applies the negative voltage to the control terminal by connecting one end of the second capacitor and the control terminal.   The booster circuit further includes an energy storage circuit for storing energy in the inductor by supplying the charge discharged from the third capacitor to the inductor through a path passing through the switching element in a conductive state. The power converter according to any one of claims 2 or 3, characterized in that The switching element includes a switching leg in which a semiconductor switching element for the upper arm and a semiconductor switching element for the lower arm are connected in series,
The power converter according to any one of claims 1 to 5, wherein the switching element is a semiconductor switching element for the upper arm.

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