WO2017163666A1

WO2017163666A1 - Resonance-type power conversion device and abnormality determining method

Info

Publication number: WO2017163666A1
Application number: PCT/JP2017/005211
Authority: WO
Inventors: 小南　智; 暢晃佐藤
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2016-03-25
Filing date: 2017-02-14
Publication date: 2017-09-28

Abstract

A resonance-type power conversion device of the present invention has a bridge circuit, a transformer, a current detection circuit, and a control circuit. The bridge circuit has a plurality of switching elements, and direct current power is inputted to the bridge circuit. The transformer is connected to the output side of the bridge circuit. The current detection circuit detects the value of a current flowing at least in one of the switching elements. On the basis of a detection value of the current detection circuit at predetermined timing while a switching control is being performed, the control circuit determines whether an abnormality has occurred in the resonance-type power conversion device.

Description

Resonant power converter and abnormality determination method

The present disclosure relates to a resonance type power converter using current resonance and an abnormality determination method.

Electric vehicles and hybrid vehicles that use storage battery power as power are in widespread use. In such electric vehicles and hybrid vehicles, a DC-DC converter, which is a power conversion device that boosts or lowers a direct current (DC) voltage for battery charging and voltage conversion, is used. In particular, since electric vehicles and hybrid vehicles require high efficiency and low noise, power converters using current resonance have been used in recent years.

A DC-DC converter using current resonance can perform zero voltage (current) switching that operates a switching element in a state where at least one of voltage and current is zero, and can reduce power loss during operation. it can.

However, in a DC-DC converter using current resonance, the resonance frequency may fluctuate due to aging deterioration of a transformer or a resonance capacitor, which is a resonance component, or a change in characteristics due to a temperature change. In such a case, since zero voltage (current) switching cannot be performed accurately, power conversion efficiency is reduced due to an increase in switching loss, switching noise is generated, a circuit is broken, and the like.

As a technique for coping with fluctuations in the resonance frequency due to changes in the characteristics of the transformer and the resonance capacitor, for example, there is a technique disclosed in Patent Document 1. Patent Document 1 discloses power conversion that resets the switching frequency only when the time during which input / output power is limited by input / output power limiting means that limits input / output power continues for a predetermined time. An apparatus is disclosed.

JP 2014-217199 A

The present disclosure provides a resonance type power converter and an abnormality determination method that can accurately detect a change in resonance frequency in a short time.

The resonant power converter of the present disclosure includes a bridge circuit, a transformer, a current detection circuit, and a control circuit. The bridge circuit has a plurality of switching elements and receives DC power. The transformer is connected to the output side of the bridge circuit. The current detection circuit detects a current value flowing through at least one of the plurality of switching elements. The control circuit determines whether an abnormality has occurred in the resonant power converter based on the detection value of the current detection circuit at a predetermined timing during switching control.

An abnormality determination method for a resonance type power converter according to the present disclosure includes: a current detection that detects a current value flowing through at least one of a plurality of switching elements, a bridge circuit having a plurality of switching elements, a transformer, and a direct current input; An abnormality of the resonance type power converter having the circuit and the control circuit is determined. In this method, the current value flowing through at least one of the plurality of switching elements is detected by the current detection circuit at a predetermined timing during the switching control. Based on the detected current value, the control circuit determines whether or not an abnormality has occurred in the resonant power converter.

According to the present disclosure, it is possible to detect fluctuations in the resonance frequency with high accuracy in a short time.

A circuit diagram showing an example of composition of a power converter concerning an embodiment of this indication Equivalent circuit diagram with parasitic elements added to the power converter shown in FIG. The figure which shows the waveform of the gate signals Vg1 and Vg2 which a control circuit outputs in order to control a bridge circuit, and the electric current value which flows through a bridge circuit A diagram comparing the current value flowing through the bridge circuit during normal operation and the current value flowing through the bridge circuit during abnormal operation The circuit diagram which shows the other example of a structure of the power converter device which concerns on embodiment of this indication

Prior to the description of the embodiment of the present disclosure, the problems in the prior art will be briefly described. With the technique disclosed in Patent Document 1 described above, it is difficult to detect a change in resonance frequency unless a predetermined time elapses, and it is difficult to detect a change in resonance frequency in a short time.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. FIG. 1 is a circuit diagram showing an example of the configuration of the power conversion apparatus 100 according to the present embodiment.

<Configuration Example of Power Conversion Device 100>
The power conversion apparatus 100 includes a DC power supply circuit 1, a bridge circuit 2, a control circuit 3, a current detection circuit 4, a resonance capacitor 5, a transformer 6, a rectifier circuit 7, and a smoothing capacitor 8.

The DC power supply circuit 1 is a device that supplies DC power, such as a fuel cell, a battery, and an AC / DC converter. A bridge circuit 2 is connected between both terminals of the DC power supply circuit 1. As shown in FIG. 1, the bridge circuit 2 includes switching elements Q1 to Q4 connected in a full bridge.

In the bridge circuit 2, switching elements Q1 and Q2 are connected in series, and switching elements Q3 and Q4 are connected in series. Switching elements Q1 and Q2 and switching elements Q3 and Q4 are connected in parallel to form a full-bridge bridge circuit 2. The switching elements Q1 to Q4 are configured by, for example, a field effect transistor (FET: Field Effect Transistor), particularly a MOSFET (Metal-Oxide-Semiconductor FET).

Switching elements Q1 to Q4 have parasitic diodes D1 to D4, respectively. Note that the switching elements Q1 to Q4 do not have the parasitic diodes D1 to D4, but diodes independent of the switching elements Q1 to Q4 may be connected in parallel.

In the bridge circuit 2, the drain terminals of the switching elements Q1 and Q3 are connected to the DC power supply circuit 1. The source terminal of the switching element Q1 is connected to the drain terminal of the switching element Q2, and the source terminal of the switching element Q3 is connected to the drain terminal of the switching element Q4. The source terminals of the switching elements Q2 and Q4 are connected to the DC power supply circuit 1 via the current detection circuit 4. Further, resonance occurs between a node n1 provided between the source terminal of the switching element Q1 and the drain terminal of the switching element Q2, and a node n2 provided between the source terminal of the switching element Q3 and the drain terminal of the switching element Q4. The capacitor 5 and the primary winding 61 of the transformer 6 are connected in series.

Furthermore, the control circuit 3 is connected to the gate terminals of the switching elements Q1 to Q4. The control circuit 3 performs on / off control (switching control) of the switching elements Q1 to Q4 at a drive frequency determined in advance based on the resonance frequency of the power conversion device 100. Thereby, the bridge circuit 2 converts the DC power of the DC power supply circuit 1 into high-frequency AC power. For example, the drive frequency may be set to a value larger by a predetermined (minute) amount than the resonance frequency at the time of circuit design. The current detection circuit 4 detects a current value that passes through the bridge circuit 2. In the present embodiment, current detection circuit 4 flows to bridge circuit 2 with the direction flowing from the side connected to switching elements Q1 and Q3 of DC power supply circuit 1 to the side connected to switching elements Q2 and Q4 being positive. Detect current.

The transformer 6 has a primary winding 61 and a secondary winding 62 that are magnetically coupled. Primary winding 61 of transformer 6 is connected to resonance capacitor 5 and a connection line between the source terminal of switching element Q3 and the drain terminal of switching element Q4. That is, the transformer 6 is connected to the output side of the bridge circuit 2. The secondary winding 62 of the transformer 6 is connected to the rectifier circuit 7. In the transformer 6, the voltage of the AC power supplied to the primary winding 61 is transformed and transmitted to the secondary winding 62. The AC power generated in the secondary winding 62 of the transformer 6 is converted into DC power by the rectifier circuit 7 and the smoothing capacitor 8 and supplied to a DC load (not shown).

FIG. 2 is an equivalent circuit diagram in which parasitic elements are added to the power conversion apparatus 100 shown in FIG. C1 to C4 are output capacities of the switching elements Q1 to Q4, Le is a leakage inductance of the transformer 6, and Lm is an exciting inductance of the transformer 6. A series LLC circuit is configured by the resonant capacitor 5, the leakage inductance Le, and the exciting inductance Lm. Below, it demonstrates using this equivalent circuit. The exciting inductance Lm and the primary winding 61 may be shared and configured as one inductor.

In the following description, a circuit composed of the bridge circuit 2, the resonance capacitor 5, the leakage inductance Le, and the excitation inductance Lm is referred to as a primary side, and a circuit composed of a rectifier circuit 7, a smoothing capacitor 8, and a DC load (not shown) is denoted as 2. Sometimes called the next side.

<Operation Principle of Power Converter 100>
Below, the operation | movement in case the power converter device 100 is operate | moving normally, and an operation principle are demonstrated. FIG. 3 is a diagram illustrating waveforms of the gate signals Vg1 and Vg2 output for the control circuit 3 to control the bridge circuit 2 and the current value flowing through the bridge circuit 2. The current value flowing through the bridge circuit 2 is the sum of the current flowing through the switching elements Q1 and Q4 and the current flowing through the switching elements Q2 and Q3. The current detected by the current detection circuit 4 as described above. Value.

The gate signal Vg1 is a signal for turning on or off the switching elements Q1 and Q4 of the bridge circuit 2, and the gate signal Vg2 is a signal for turning on or off the switching elements Q2 and Q3. In the following description, the gate signal Vg1 will be described for the case where the switching elements Q1 and Q4 are turned on or off at the same time. For example, Q4 is turned on or off slightly after the switching element Q1. May be. Similarly, in the following description, the case where the gate signal Vg2 turns on or off the switching elements Q2 and Q3 at the same time will be described. For example, Q3 is turned on or off slightly after the switching element Q2. It may be.

As shown in FIG. 3, times t ₁ and t ₅ indicate the timing when the switching elements Q1 and Q4 are turned on, and times t ₂ and t ₆ indicate the timing when the switching elements Q1 and Q4 are turned off. Times t ₃ and t ₇ indicate timings at which the switching elements Q2 and Q3 are turned on, and times t ₀ and t ₄ indicate timings at which the switching elements Q2 and Q3 are turned off. In addition, after switching elements Q1 and Q4 are turned off until switching elements Q2 and Q3 are turned on, and between when switching elements Q2 and Q3 are turned off and until switching elements Q1 and Q4 are turned on, Dead time (td) is provided.

As described above, the current value detected by the current detection circuit 4 is a measured value of the current passing through the bridge circuit 2. As described above, the signal detected by the current detection circuit 4 is positive in the direction flowing from the side connected to the switching elements Q1 and Q3 of the DC power supply circuit 1 to the side connected to the switching elements Q2 and Q4.

At time _{t 1} shown in FIG. 3, the control circuit 3 when the launch to High (high-level) gate signal Vg1 from Low (low-level), the switching elements Q1 and Q4 are turned on. The switching elements Q1 and Q4 from time t ₁ to time t ₂ is turned on, the switching element Q1 from the DC power supply circuit 1, the resonance capacitor 5, primary winding 61 of the transformer 6, the load current in the order of the switching element Q4 Flowing. That is, as shown in FIG. 3, the value of the current flowing through the bridge circuit 2 increases in the positive direction.

When an input voltage is applied to the LLC circuit constituted by the resonance capacitor 5, the leakage inductance Le, and the excitation inductance Lm, electric charges are accumulated in the resonance capacitor 5 by the resonance operation. In addition, the resonance current due to the resonance capacitor 5 and the leakage inductance Le is discharged through the secondary winding 62 to a DC load (not shown).

As the voltage of the resonant capacitor 5 increases, the voltage applied to the primary winding 61 decreases. For this reason, the current discharged to the secondary side is also reduced. When the resonance ends and the secondary side current becomes zero, the exciting current flows only on the primary side, and the charging of the resonant capacitor 5 is maintained.

In time _{t 2, the} control circuit 3 when the fall to Low gate signal Vg1 from High, the switching elements Q1 and Q4 are turned off. Immediately after the switching elements Q1 and Q4 are turned off, the output capacitor C1 and the output capacitor C4 are charged by the exciting current flowing through the primary side, and the output capacitor C2 and the output capacitor C3 are discharged. As a result, the drain-source voltage of switching elements Q1 and Q4 increases, and the drain-source voltage of switching elements Q2 and Q3 decreases. When the drain-source voltage of the switching elements Q2 and Q3 decreases to zero, the exciting current in a direction to reset the excitation energy accumulated in the leakage inductance Le and the exciting inductance Lm through the parasitic diodes D2 and D3 of the switching elements Q2 and Q3. Flows.

Incidentally, during the period from time t ₂ to time t ₃ is a period of dead time, all the switching elements Q1 ~ Q4 is off.

At time _{t 3,} the control circuit 3 when launching the High gate signal Vg2 from Low, the switching elements Q2 and Q3 are turned on. At this time, since the exciting current flows in the switching elements Q2 and Q3 in the direction from the source to the drain, that is, in the negative direction, the switching is performed at the timing when the drain-source voltages of the switching elements Q2 and Q3 are zero. For this reason, zero-voltage switching (ZVS) is achieved, and switching loss at turn-on can be avoided.

Switching elements Q2 and Q3 from time t ₃ to time t ₄ is in the ON state, the exciting current flows through the series LLC circuit by the voltage charged in the resonant capacitor 5, the charge of the resonance capacitor 5 is discharged. At the same time, a resonance current caused by the resonance capacitor 5 and the leakage inductance Le is discharged through a secondary winding 62 to a DC load (not shown).

As the voltage of the resonant capacitor 5 decreases, the voltage applied to the primary winding 61 decreases. For this reason, the current discharged to the secondary side is also reduced. When the current on the secondary side becomes zero, an exciting current flows only on the primary side, and charging of the resonant capacitor 5 is maintained.

At time _{t 4,} the control circuit 3 when the fall to Low gate signal Vg2 from High, the switching elements Q2 and Q3 are turned off. Immediately after the switching elements Q2 and Q3 are turned off, the output capacitor C1 and the output capacitor C4 are discharged by the exciting current flowing through the primary side, and the output capacitor C2 and the output capacitor C3 are charged. As a result, the drain-source voltage of switching elements Q1 and Q4 decreases, and the drain-source voltage of switching elements Q2 and Q3 gradually increases.

When the drain-source voltage of switching elements Q2 and Q3 rises to the input voltage, it is regenerated in DC power supply circuit 1 through parasitic diode D1 and parasitic diode D4 of switching elements Q1 and Q4, and is stored in leakage inductance Le and excitation inductance Lm. The resonance current continues to flow in the direction to reset the excitation energy. Thereafter, the switching elements Q1 and Q4 again at time _{t 5} is turned on. Operation of the time t ₅ is the same operation as the operation at time t _1, hereinafter the same operation is repeated.

The turn-on operation of switching elements Q1 and Q4 at time t ₅ (t ₁ ) is switching at a timing when the drain-source voltage of switching elements Q1 and Q4 is zero. For this reason, zero voltage switching is performed, and switching loss at turn-on can be avoided.

<Operation Example of Power Conversion Device 100 at Abnormal Time>
Next, an operation example when an abnormality occurs in the power conversion device 100 will be described. In the embodiment of the present disclosure, the abnormality is assumed to be a failure of the resonant capacitor 5. Specifically, for example, when a plurality of capacitors are connected in parallel to form the resonance capacitor 5, one of them has failed, and the capacitance of the resonance capacitor 5 has decreased. State.

Generally, the resonance frequency fr of the series LLC circuit is calculated by the following formula (1).

That is, when an abnormality occurs in the power conversion device 100 in which the capacitance C of the resonance capacitor 5 decreases, the resonance frequency of the series LLC circuit increases.

As described above, the drive frequency of the bridge circuit 2 is designed to be larger by a predetermined minute amount than the resonance frequency at the time of circuit design. For this reason, when the resonance frequency of the series LLC circuit increases due to an abnormality in the power conversion device 100, the increased resonance frequency exceeds the drive frequency of the bridge circuit 2.

Thereby, the resonance operation of the series LLC circuit shifts to the phase advance side, and the resonance current flowing through the series LLC circuit becomes the phase advance. FIG. 4 is a diagram comparing the current value flowing through the bridge circuit 2 during normal operation and the current value flowing through the bridge circuit 2 during abnormal operation.

As shown in FIG. 4, when the current is shifted to the phase advance side at the time of abnormality, the period from turning off the switching elements Q1 and Q4 of the bridge circuit 2 to turning off the switching elements Q2 and Q3 is one cycle. The current waveform during abnormal operation is such that the current waveform during normal operation is reversed left and right every cycle.

<Abnormal operation detection processing>
Based on the above, the abnormal operation detection process in the power conversion device 100 according to the embodiment of the present disclosure will be described.

As shown in FIG. 4, there is a clear difference in the current value flowing through the bridge circuit 2 detected by the current detection circuit 4 between the normal operation and the abnormal operation. Therefore, the control circuit 3 refers to the detection value of the current detection circuit 4 at the predetermined timing by determining in advance the range that can be taken by the current value at the normal operation at the predetermined timing. Can be determined whether or not the power conversion apparatus 100 is operating abnormally.

The range of current values that can be taken during normal operation at a predetermined timing includes the current value that flows through the bridge circuit 2 during normal operation (current during normal operation) and the current that flows through the bridge circuit 2 during abnormal operation as shown in FIG. What is necessary is just to experimentally acquire a value (current at the time of abnormality) beforehand and to confirm by comparing these.

Hereinafter, a specific example will be described. As the first example, the control circuit 3, for example, time t _1, t _3, and t, such as ₅ or the like, the current value during the rise of the gate signal Vg1 or Vg2, an abnormality is determined whether or not. When the gate signal Vg1 or Vg2 rises, that is, when the switching elements Q1 and Q4 or Q2 and Q3 are turned on, the normal current passes through the parasitic diode D3 and the parasitic diode D2 of the switching elements Q3 and Q2, and passes through the bridge circuit 2. Backflow. For this reason, the current value is always smaller than zero as shown in the normal current in FIG.

On the other hand, during an abnormal operation, the current shifts to the leading phase, so that the current value at the rising edge of the gate signal Vg1 or Vg2 may be zero or more as shown in the abnormal current in FIG. That is, when the control circuit 3 raises the gate signal Vg1 or Vg2 from Low to High, the control circuit 3 refers to the current value flowing through the bridge circuit 2 obtained from the current detection circuit 4, and the value is greater than zero. In this case, it can be determined that an abnormal operation has occurred in the power conversion device 100. When it is determined that an abnormal operation has occurred in the power conversion apparatus 100, the control circuit 3 outputs a signal indicating that an abnormal operation has occurred to the outside (for example, a higher-level control circuit).

Note that the abnormal current illustrated in FIG. 4 is an example, and the current value detected by the current detection circuit 4 during the abnormal operation of the power conversion apparatus 100 does not always have such a waveform. For this reason, even if the current value at the time of rising of the gate signal Vg1 or Vg2 is a value smaller than zero, an abnormality may occur in the power conversion device 100. However, when the resonance frequency is greatly increased from the time of circuit design, the current shifts to the phase advance side, so that the current value at the rise of the gate signal Vg1 or Vg2 becomes a value larger than zero. When the resonance frequency is greatly increased from the circuit design time, not only can the zero voltage switching not be performed in the bridge circuit 2, but also, for example, a through current flows from the switching element Q1 to Q2, or the bridge circuit 2 The power conversion device 100 may break down due to heat generation, or the like may occur. Although the above-described abnormality detection method for the control circuit 3 may not be able to detect a small fluctuation of the resonance current from the circuit design time, it can accurately detect a big fluctuation that causes the power conversion device 100 to be destroyed. be able to.

As a second example, the control circuit 3 determines whether or not there is an abnormality based on the current value when a little time elapses from the time when the gate signal Vg1 or Vg2 falls, for example. In FIG. 4, the points in time when the gate signal Vg1 or Vg2 falls slightly are indicated as t ₂ ′, t ₄ ′, and t ₆ ′. As shown in FIG. 4, when the gate signal Vg1 or Vg2 falls, that is, immediately after the switching elements Q1 and Q4 or Q2 and Q3 are turned off, the normal-time current is accompanied by the turn-off as shown in FIG. 2 flows backward, but then increases in the positive direction. On the other hand, as shown in FIG. 4, the abnormal current does not flow back through the bridge circuit 2 and then increases in the positive direction.

For this reason, the control circuit 3 refers to the current value flowing through the bridge circuit 2 acquired from the current detection circuit 4 when the gate signal Vg1 or Vg2 falls, and if the value is greater than zero, Then, it is determined that an abnormal operation has occurred in the power conversion device 100. As in the first example, when it is determined that an abnormal operation has occurred in the power conversion device 100, the control circuit 3 has an abnormal operation outside (for example, a higher-level control circuit). The signal which shows that is output.

As described above, the predetermined timing for specifying the current value range in normal operation in advance has been described with reference to two specific examples. However, the present disclosure is not limited to these two examples. Any timing may be used as long as it can clearly discriminate between a normal current and an abnormal current in which the resonance frequency fluctuates greatly from the circuit design time.

As described above, the power conversion device 100 according to the embodiment of the present disclosure includes the bridge circuit 2, the transformer 6, the current detection circuit 4, and the control circuit 3. The bridge circuit 2 has a plurality of switching elements and receives DC power. The transformer 6 is connected to the output side of the bridge circuit 2. The current detection circuit 4 detects a current value flowing through at least one of the plurality of switching elements. The control circuit 3 determines whether or not an abnormality has occurred in the power conversion device 100 based on the detection value of the current detection circuit 4 at a predetermined timing during switching control.

With such a configuration, it is possible to accurately detect an abnormality of the power conversion apparatus 100 such as a significant increase in the resonance frequency without requiring time for detection.

Although various embodiments have been described above with reference to the drawings, the present disclosure is not limited to such examples. Since it is clear that those skilled in the art can arrive at various changes and modifications within the scope of the claims, they also fall within the technical scope of the present disclosure.

In the above-described embodiment, the current detection circuit 4 is connected downstream of the bridge circuit 2 and detects the current value flowing through the bridge circuit 2, but the present disclosure is not limited to this. For example, the current detection circuit 4 may be installed upstream of the bridge circuit 2 or inside the bridge circuit 2. Further, the current detection circuit 4 may detect only the current value flowing through one of the switching elements, instead of detecting the current value flowing through the entire bridge circuit 2. In this case, the range of the current value flowing through the switching element during normal operation and abnormal operation is acquired in advance, and the control circuit 3 determines whether or not the operation is abnormal based on this range. That's fine.

In the above-described embodiment, the power conversion device 100 including the full-bridge bridge circuit 2 has been described, but the present disclosure is not limited thereto. For example, as shown in FIG. 5, you may have the bridge circuit 21 of a half bridge.

In the above-described embodiment, the power conversion device 100 including the transformer 6 has been described, but the present disclosure is not limited to this. For example, a primary winding (power feeding coil) and a secondary winding (power receiving coil) used for non-contact charging may be used as the transformer 6.

In the above-described embodiment, when it is determined that an abnormal operation has occurred, a signal indicating that the abnormal operation has occurred is output to the outside (for example, a higher-level control circuit). This is not a limitation. For example, the operation (power conversion) may be continued by changing the drive frequency so that the value is larger by a predetermined amount than the fluctuating resonance frequency.

The present disclosure is suitable as a power conversion device that transforms DC power.

100 Power converter 1 DC

power supply circuit

2, 21 Bridge circuit Q1, Q2, Q3, Q4 Switching element D1, D2, D3, D4 Parasitic diode C1, C2, C3, C4 Output capacity 3 Control circuit 4 Current detection circuit 5 Resonant capacitor 6 transformer 61 primary winding 62 secondary winding 7 rectifier circuit 8 smoothing capacitor Le leakage inductance Lm exciting inductance n1, n2 node

Claims

A bridge circuit having a plurality of switching elements and receiving DC power;
A transformer connected to the output side of the bridge circuit;
A current detection circuit for detecting a current value flowing through at least one of the plurality of switching elements;
A resonant power converter comprising a control circuit,
The control circuit determines whether or not an abnormality has occurred in the resonant power converter based on a detection value of the current detection circuit at a predetermined timing during switching control.
Resonant power converter.
The control circuit determines an increase of the resonance frequency over a predetermined frequency from the circuit design time as the abnormality of the resonance type power converter,
The resonant power converter according to claim 1.
When the control circuit determines that the abnormality has occurred, the control circuit outputs a signal indicating that the abnormality has occurred.
The resonance type power converter according to claim 1 or 2.
The predetermined timing is a timing at which the control circuit outputs a control signal for turning on the switching element of the bridge circuit,
The control circuit determines that the abnormality has occurred in the resonant power conversion circuit when a detection value of the current detection circuit at the timing of outputting the control signal is greater than zero.
The resonance type power converter according to claim 1 or 2.
The predetermined timing is a timing at which a predetermined minute time has elapsed after the control circuit outputs a control signal for turning on the switching element of the bridge circuit,
The control circuit generates the abnormality in the resonant power conversion circuit when a detection value of the current detection circuit at the timing when the predetermined minute time has elapsed after outputting the control signal is greater than zero. It is determined that
The resonance type power converter according to claim 1 or 2.
The bridge circuit is a full bridge circuit,
The resonance type power converter according to claim 1 or 2.
The bridge circuit is a half bridge circuit,
The resonance type power converter according to claim 1 or 2.
A bridge circuit having a plurality of switching elements, to which DC power is input, a transformer connected to the output side of the bridge circuit, and a current for detecting a current value flowing through at least one of the plurality of switching elements An abnormality determination method for a resonant power converter having a detection circuit and a control circuit,
Detecting a current value flowing through at least one of the plurality of switching elements by the current detection circuit at a predetermined timing during switching control; and
Based on the detected current value, the control circuit determines whether or not an abnormality has occurred in the resonant power converter.
Abnormality judgment method.