JP5452551B2 - Power conversion device and power conversion system - Google Patents

Description

  The present invention relates to an inverter control device that detects a surge voltage generated when a semiconductor switching element constituting an inverter main circuit is cut off and compares it with a current command value to detect an abnormality in the inverter main circuit.

  2. Description of the Related Art Conventionally, in a power conversion device including a plurality of switching elements, a technique for preventing overvoltage breakdown from a surge voltage generated when the switching element is interrupted is known. For example, in Patent Document 1, a collector voltage of a switching element is known. The surge voltage is detected by detecting the potential obtained by dividing the motor, and the torque of the motor is limited by the motor torque limit command signal when an abnormality is determined.

  Furthermore, in Patent Document 2, when the voltage applied between the collector and the emitter of the IGBT becomes abnormal in the constant voltage level of the constant voltage diode, the gate current is passed through the constant voltage diode and the diode to slowly turn off. Therefore, an excessive voltage is prevented from being applied.

JP 2004-236371 A JP-A-7-170654

  However, in any of the above-mentioned patent documents, detection of the maximum surge voltage at the time of driving a large current is assumed, and the surge voltage in a small current region frequently used at the time of actual motor driving is considered. Not. For this reason, there is a possibility that the reliability of the abnormality detection of the inverter main circuit is impaired.

  Then, the objective of this invention is providing the power conversion system and power converter device which can aim at the further reliability improvement.

  In order to solve the above problem, for example, a surge voltage detection signal detected by a surge voltage detection circuit is input to a motor control circuit, and when a surge voltage detection signal is detected, a current command value from the current command generation unit and A means for selecting whether or not to implement the surge voltage suppressing means for suppressing the surge voltage by comparing with a predetermined current command value may be provided.

  ADVANTAGE OF THE INVENTION According to this invention, a reliable power conversion system and power converter device can be provided.

It is a control block diagram of the motor control device of the power conversion system according to the embodiment of the present invention. It is a block diagram of the surge voltage detection apparatus which concerns on embodiment of this invention. 1 is a surge voltage detection circuit according to a first embodiment of the present invention. It is a surge voltage detection operation waveform which concerns on the 1st Embodiment of this invention. It is a flowchart of the surge voltage detection which concerns on the 1st Embodiment of this invention. It is an example of a waveform at the time of 50A and 650A interruption | blocking of a semiconductor switching element. It is an example of the relationship between the collector current and surge voltage in a semiconductor switching element. It is a surge voltage detection circuit which concerns on the 2nd Embodiment of this invention. It is a flowchart of the surge voltage detection which concerns on the 2nd Embodiment of this invention. It is a surge voltage detection circuit which concerns on the 3rd Embodiment of this invention. It is a surge voltage detection circuit which concerns on the 3rd Embodiment of this invention. It is a flowchart of the surge voltage detection which concerns on the 3rd Embodiment of this invention. It is the surge voltage detection level which concerns on the 3rd Embodiment of this invention, and the protection range of a semiconductor switching element. It is a surge voltage detection circuit which concerns on the 4th Embodiment of this invention. It is a surge voltage detection circuit which concerns on the 4th Embodiment of this invention.

  The principle of the power conversion system and the power conversion device according to the embodiment of the present invention will be briefly described.

  A power conversion system including an inverter is configured by a combination of semiconductor switching elements, and performs power conversion by sequentially switching each element. During the switching operation of the semiconductor switching element, a jumping (surge) voltage is generated due to the switching speed when the semiconductor switching element is cut off.

  When this surge voltage exceeds the withstand voltage of the semiconductor switching element with respect to the voltage applied between the collector and emitter (or between the drain and source) of the semiconductor switching element, the semiconductor switching element is caused by its own surge voltage. There is a possibility of overvoltage breakdown.

  The surge voltage is a voltage proportional to the main circuit inductance L or current change rate di / dt calculated by V = L × di / dt. That is, as the output current of the inverter increases and di / dt increases, the surge voltage generated increases in proportion to the output current value.

  In general, when designing a gate drive circuit of a semiconductor switching element, matching such as setting a gate resistance is performed so that a surge voltage of the semiconductor switching element to be used does not exceed a withstand voltage. For this reason, the surge voltage itself is not monitored. Even if the surge voltage is expanded due to deterioration of the main circuit inductance or current change rate due to aging degradation or system malfunction while driving the power conversion system, the semiconductor It was difficult to catch the switching element until it was destroyed.

  A power conversion system and a power conversion device according to an embodiment of the present invention monitor a surge voltage detection signal from a surge voltage detection means provided in a gate drive circuit, and generate a current generated by a current command generation unit of a motor control circuit. A comparison is made between the command value and a surge voltage value relative to the current command value.

  Here, when a surge voltage exceeding a predetermined voltage value relative to the inverter output current value is detected, a surge voltage abnormality detection signal is output, and the current control system gain adjustment and output current are limited. Therefore, it is possible to prevent an excessive surge voltage from being applied to the semiconductor switching element.

  In particular, since the change of the main circuit impedance can be detected at an early stage by positively detecting the surge voltage in the small current region, it is possible to provide a motor control device capable of further improving the reliability.

  Hereinafter, it will be described in detail with reference to the drawings.

<First Embodiment>
FIG. 1 is a control block diagram of a motor control device of a power conversion system according to an embodiment of the present invention. The motor 1 is a permanent magnet synchronous motor, and the rotation speed and the magnetic pole position are detected by a rotation sensor such as a resolver or an encoder. The motor 1 is connected to the inverter circuit 2 via a cable, and is supplied with electric power.

  The inverter circuit 2 is composed of a semiconductor switching element such as an IGBT and performs power conversion by switching the upper and lower arms of each phase with a PWM signal. The current output from the inverter circuit 2 and flowing to the motor 1 via the cable is detected by the current sensor 3. The inverter output current value detected by the current sensor 3 is fed back to the current control unit 8 via an A / D conversion function included in the arithmetic processing unit in the motor control circuit 4.

  FIG. 2 is a block diagram of the surge voltage detection apparatus according to the embodiment of the present invention.

The current command is generated by the current command generator 7 of the motor control circuit 4 based on the torque command value τ ^* from the host controller, the rotational speed ω of the motor 1 and the magnetic pole position θ. The generated current command value is converted by the current control unit 8 of the motor control circuit 4 from the feedback value of the inverter output current detected by the current sensor 3 and converted into a PWM signal through the controller. The PWM signal drives a semiconductor switching element such as an IGBT through the gate drive circuit 5.

  Next, the surge voltage detection means in the first embodiment will be described below.

  FIG. 3 is a surge voltage detection circuit according to the first embodiment. A circuit in which a Zener diode having a predetermined Zener voltage, a backflow prevention diode, and a resistor are connected in series is connected in parallel with the semiconductor switching element between the collector and the emitter (or between the drain and source) of the semiconductor switching element. . With this circuit configuration, a Zener current generated when a surge voltage applied between the collector and the emitter (or between the drain and source) when the semiconductor switching element is cut off exceeds a predetermined Zener voltage is detected.

  Next, surge voltage detection operation waveforms according to the first embodiment will be described with reference to FIG. A Zener diode having a predetermined Zener voltage Vz causes a Zener current Iz to flow when a surge voltage exceeding Vz is applied. Since the Zener current is a minute current, the detection level is amplified by a differential amplifier circuit as shown in FIG.

  In addition, the surge voltage is a voltage that changes in a short time of several tens of ns, and in order to capture this voltage as a detection signal, the surge voltage detection circuit has a latch circuit that detects the detected zener current for a certain period of time or detects it. It is desirable to provide a one-shot pulse output circuit triggered by a Zener current.

  The surge voltage detection signal Vs detected by the surge voltage detection circuit is input to an arithmetic processing unit or the like provided in the motor control circuit by an insulating transmission element such as a photocoupler. The arithmetic processing unit determines whether or not a surge voltage exceeding a predetermined voltage value is applied based on the level (H / L) of the input surge voltage detection signal Vso.

  FIG. 5 is a flowchart of surge voltage detection according to the first embodiment. Step S101 is a level determination unit for the surge voltage detection signal Vso from the surge voltage detection circuit shown in FIG. When a surge voltage exceeding a predetermined voltage value is applied, Vso is input as L from the surge voltage detection circuit.

  On the other hand, when the surge voltage detection signal Vso is H, a surge voltage higher than a predetermined voltage value is not generated, and normal inverter driving is continued. If the surge voltage detection signal Vso is L, the validity comparison of the current command value at the time of detecting the surge voltage is performed in the next step S102.

  Here, in the arithmetic processing unit on the motor control circuit, the current command value is monitored as needed, and the current command value Is_cmd at the time when the surge voltage detection signal Vso is input at the L level is stored in the memory. On the other hand, since the surge voltage detection level can be set by the Zener voltage, an arbitrary surge voltage detection level is set in advance. Based on the correlation with the output current value and the surge voltage, the surge voltage detection circuit is configured using a Zener diode having a Zener voltage larger than the surge voltage generated during driving at a predetermined current command value I_cmd.

  In step S102, the current command value Is_cmd at the time of detecting the surge voltage is compared with a predetermined current command value I_cmd that is set in advance. If Is_cmd ≦ I_cmd, a surge that does not occur originally is generated. It is determined that

  During normal operation, the surge voltage for the predetermined current value I_cmd does not exceed the set Zener voltage, and thus no surge voltage detection signal is output. In addition, when the current command value Is_cmd at the time of detecting the surge voltage is equal to or greater than a predetermined current command value (Is_cmd> I_cmd), the current motor region may detect the surge voltage. Continue.

  If the current command value is less than or equal to the set current command value in step S102 (Is_cmd ≦ I_cmd), it is determined that a surge voltage abnormality has occurred, and a surge voltage abnormality / main circuit abnormality determination signal is output in step S103. Output. Further, in response to the surge voltage abnormality signal from step S103, in step S104, a current output limit signal for limiting the output current value for the subsequent motor drive is output.

  By suppressing the inverter output current value based on the surge voltage abnormality determination, it is possible to prevent overvoltage breakdown of the semiconductor switching element due to the surge voltage at the time of large current driving. In addition, since a main circuit abnormality can be detected during a current shift to a large current drive by detecting a surge voltage abnormality in a small current region at an early stage, a highly reliable power conversion system and power conversion device are provided. Can do.

  The surge voltage detection in this embodiment will be described below using a specific example.

  FIG. 6 is an example of operation waveforms of the collector voltage and the collector current when the semiconductor switching element is cut off. FIG. 6A shows the collector voltage and collector current when 50A is cut off, and FIG. 6B shows the collector voltage and collector current when 650A is cut off. FIG. 7 shows an example of the relationship between the collector current and the surge voltage in the semiconductor switching element. The surge voltage at the time of 50A and 650A interruption | blocking reaches 450V and 620V, respectively, and a surge voltage is so large that output current is large.

  Here, the surge voltage detection level is set to 480 V, surge voltage detection is performed using a Zener diode with a Zener voltage Vz = 480 V, and a predetermined current command value for comparing validity with an arithmetic processing unit when a surge voltage abnormality is detected is I_cmd = 50A.

  The surge voltage at the time of normal 50A interruption | blocking is 450V, and since the Zener voltage is 480V or less, a surge voltage detection signal is not output. On the other hand, since the surge voltage exceeds 480V when shut off at 200A or higher, a surge voltage detection signal is output, but the validity of the current command value in the arithmetic processing unit provided in the motor control circuit As a result of comparison, abnormality determination is not performed because Is_cmd> 50A.

  The broken line graph shown in FIG. 7 assumes a case where the surge voltage is expanded due to an increase in main circuit inductance due to aged deterioration of the power conversion system or a failure of a current sensor or the like. Assuming that the surge voltage with respect to the collector current increases as a whole by 30V, the 450V surge voltage that was generated when the 50A was shut off expanded to 480V, and the 620V surge voltage that occurred when the 650A was shut off expanded to 650V. End up. As a result, the surge voltage at the time of 650A interruption | blocking will reach 650V which is the pressure | voltage resistance of an IGBT element, and it may lead to an overvoltage destruction.

  However, by applying this embodiment, a 480V surge voltage detection level and a predetermined current command value I_cmd = 50A are set, so that the 480V surge voltage generated when the current command 50A is cut off is detected as an abnormal voltage. be able to. Furthermore, application of a surge voltage of 650 V when 650 A is interrupted can be avoided by detecting a surge voltage abnormality at the time of small current driving and limiting the current command value.

  As described above, when a surge voltage abnormality signal is recognized in a small current region that should not be detected depending on the presence or absence of a surge voltage detection signal for a given current command value, the main circuit inductance or current change rate is abnormal. Can be recognized in the motor control system, and by using surge voltage suppression means such as current command limitation, application of surge voltage due to large current drive to the semiconductor switching element can be avoided .

<Second Embodiment>
FIG. 8 shows a surge voltage detection circuit according to the second embodiment. The basic motor control block diagram shown in FIGS. 1 and 2 is the same as that of the first embodiment. Further, the validity comparison of the current command value in the surge voltage detection method and the arithmetic processing unit is the same as that in the first embodiment.

  The surge voltage detection circuit according to the second embodiment is a mode in which a gate resistance switching function is added to the gate drive circuit in addition to the first embodiment.

  The gate resistors to be connected are a resistor A having a gate resistance value R during normal driving and a resistor B having a gate resistance value Rs larger than R (R <Rs). The gate resistor is connected to the resistor A during normal motor driving.

  FIG. 9 is a flowchart of surge voltage detection according to the second embodiment. As in the first embodiment, a predetermined surge voltage detection level is set, and the arithmetic processing unit on the motor control device compares the current command value at the time of surge voltage detection in step S102 to detect the surge voltage detection. The current command value Is_cmd is compared with a predetermined current command value I_cmd set in advance, and if it is determined that Is_cmd ≦ I_cmd, a signal for determining surge voltage abnormality and main circuit abnormality is output from step S103. In response to the surge voltage abnormality signal from step S103, a gate resistance switching signal is output in step S105. By switching the connection from the resistor A connected during normal driving to the gate resistor B having a resistance value larger than that of the gate resistor A in the gate drive circuit by the gate resistance switching signal output from the arithmetic processing unit. The surge voltage is suppressed by adjusting di / dt of the semiconductor switching element.

  The present embodiment may be used in combination with the output current value limitation shown in the first embodiment.

<Third Embodiment>
FIG. 10 shows a surge voltage detection circuit according to the third embodiment. The basic motor control block diagram shown in FIGS. 1 and 2 is the same as that of the first embodiment.

  The surge voltage detection circuit according to the third embodiment, in addition to the first or second example, connects a circuit in which a Zener diode having different Zener voltage, a backflow prevention diode, and a resistor are connected in series to a semiconductor switching element. Thus, a surge voltage detection circuit having a different surge voltage detection level is added. The surge voltage detection circuits 1 to 3 use Zener diodes 1 to 3 having different Zener voltages, and have a latch circuit or a one-shot pulse output circuit that holds the detected Zener current for a predetermined time.

  Here, arbitrarily set Zener voltages Vz1 to Vz3 are surge voltage detection levels, and when a surge voltage exceeding each detection level is applied, detection signals Vso1 to Vso3 are output from the respective surge voltage detection circuits. Is done. Here, each Zener diode has a different Zener voltage such that Zener voltage 1 <Zener voltage 2 <Zener voltage 3.

  As shown in FIG. 11, the surge voltage detection level may be set by connecting a plurality of Zener diodes having different Zener voltages in series.

  FIG. 12 is a flowchart of surge voltage detection in the third embodiment. Since the detected surge voltage levels can be classified according to the output surge voltage detection signals Vso1 to Vso3, current command values I_cmd_1 to I_cmd_3 for validity comparison are set for the respective surge voltage levels.

  Here, as the surge voltage detection level, the Zener voltages of the Zener diodes 1 to 3 are set as Vz1 = 480V, Vz2 = 540V, Vz3 = 600V, and the comparison current command values are I_cmd_1 = 50A, I_cmd_2 = 300A, I_cmd_3 = 500A.

First, in steps S201 to 203, by the H / L combination of the surge voltage detection signals Vso1, Vso2, and Vso3,
Vso1 = L, Vso2 = H, Vso3 = H is a surge voltage detection of 480V or more and less than 540V,
Vso1 = L, Vso2 = L, Vso3 = H is a surge voltage detection of 540V or more and less than 600V,
Vso1 = L, Vso2 = L, Vso3 = L are surge voltage detection of 600V or more,
Thus, the detected surge voltage level can be classified.

  In step S201, the presence or absence of detection of a surge voltage of 480 V or more is determined by a surge voltage detection signal Vso1.

  When Vso1 = H, it is determined that no surge voltage is detected, and the motor drive is continued.

  When Vso1 = L, the presence or absence of surge voltage detection of 540 V or more is determined by the surge voltage detection signal Vso2 in step S202.

  When Vso2 = H, it is determined that a surge voltage of 480 V or more and less than 540 V is detected, and in step S211, the current command value Is_cmd at the time of surge voltage detection is compared with a preset current command value I_cmd_1 = 50A. If Is_cmd ≦ I_cmd_1, a surge voltage abnormality signal is output in step S221, and surge voltage suppression means is implemented by switching gate resistance on the gate drive circuit in step S231. On the other hand, if Is_cmd> I_cmd_1, it is determined that the surge voltage is detected by the large current drive, and the normal motor drive is continued.

  If Vso2 = L, the presence or absence of surge voltage detection of Vz3 = 600V or higher is determined based on the surge voltage detection signal Vso3 in step S203.

  If Vso3 = H, it is determined that a surge voltage of 540 V or more and less than 600 V is detected, and in step S212, the current command value Is_cmd at the time of surge voltage detection is compared with a preset current command value I_cmd_2 = 300A. If Is_cmd ≦ I_cmd_2, a surge voltage abnormality signal is output in step S222, and surge voltage suppression means by current command restriction is implemented in step S232. On the other hand, if Is_cmd> I_cmd_2, there is a surge voltage abnormality with respect to the current command value, but it can be determined that the motor can be continuously driven. Therefore, a surge voltage abnormality signal is output in step S211 and a gate drive circuit in step S231. Implement surge voltage suppression means by switching the gate resistance above.

  If Vso3 = L, it is determined that a surge voltage of 600 V or higher is detected, and in step S213, the current command value Is_cmd at the time of detecting the surge voltage is compared with a preset current command value I_cmd_3 = 500A. If Is_cmd ≦ I_cmd_3, it can be determined that a surge voltage of 600 V or more is generated at the time of interruption at 500 A or less, so a surge voltage abnormality signal is output in step S223 and the motor drive is immediately stopped in step S233.

  On the other hand, if Is_cmd> I_cmd_3, there is a surge voltage abnormality with respect to the current command value, but it can be determined that the motor can be continuously driven. Therefore, a surge voltage abnormality signal is output in step S222 and the current command is limited in step S232. Implement surge voltage suppression means.

  FIG. 13 shows the surge voltage detection level and the protection range of the semiconductor switching element according to the third embodiment. The range surrounded by the surge voltage detection level Vz and the predetermined current command value I_cmd is the range to which each surge voltage suppression means is applied. According to the above-described embodiment, the current command value I_cmd_1 = 50A and the surge voltage detection The level Vz1 = 480V is set, and in the range surrounded by the two-dot chain line, the surge voltage suppression means is implemented by switching the gate resistance, and the current command value I_cmd_2 = 300A and the surge voltage detection level Vz2 = 540V are set. In the range surrounded by, the surge voltage suppression means by the current command restriction is implemented, the current command value I_cmd_3 = 500A and the surge voltage detection level Vz2 = 600V are set, and the motor drive is stopped in the range surrounded by the solid line.

  As described above, the surge voltage suppression means can be switched by comparing a plurality of provided surge voltage detection levels with the current command value at the time of surge voltage detection.

  The combination of surge voltage suppression means implemented for the surge voltage detection level is arbitrary, and by having various surge voltage suppression means, a power conversion system capable of continuing motor driving while avoiding overvoltage breakdown of the semiconductor switching element, and A power converter can be provided.

<Fourth Embodiment>
FIG. 14 shows a surge voltage detection circuit according to the fourth embodiment. The basic motor control block diagram shown in FIGS. 1 and 2 is the same as that of the first embodiment. The surge voltage detection circuit in the fourth embodiment directly detects a voltage applied between the collector and emitter (or drain and source) of the semiconductor switching element by dividing the voltage with a resistor. The divided collector (or drain) voltage is output for a certain period of time as a peak value Vp of the applied surge voltage through the peak hold circuit. The surge voltage detection level is determined by the voltage dividing ratio of the voltage dividing resistor.

  Further, as shown in FIG. 15, the divided collector (or drain) voltage may be converted to a level that can be detected via a differential amplifier circuit or the like and detected by an arithmetic processing unit such as a microcomputer. By using an arithmetic processing unit or the like, the surge voltage detection level can be arbitrarily set by software. Then, the output of the surge voltage detection signal Vs is determined by comparing the surge voltage detection level arbitrarily set in the arithmetic processing unit with a threshold value and comparing the peak value of the surge voltage output from the peak hold circuit.

  The surge voltage peak value Vp or surge voltage detection signal Vs detected by the surge voltage detection circuit described above is input to an arithmetic processing unit or the like provided in the motor control circuit by an insulating transmission element such as a photocoupler. The arithmetic processing unit determines whether or not a surge voltage exceeding a predetermined voltage value is applied based on the level (H / L) of the input surge voltage detection signal Vso.

  As in the first embodiment, the processing after the surge voltage abnormality detection in the present embodiment implements a means for limiting a current command as a surge voltage suppressing means in accordance with the flowchart shown in FIG. Further, when the gate resistance switching function is provided as in the second embodiment, the gate resistance switching means may be implemented as the surge voltage suppressing means according to the flowchart shown in FIG. Further, when a plurality of surge voltage detection circuits are provided as in the third embodiment, means for switching the plurality of surge voltage suppression means according to the surge voltage detection level and the current command value according to the flowchart shown in FIG. You may carry out.

  As described above, by applying the first to fourth embodiments, it is possible to prevent a semiconductor switching element such as an IGBT from overvoltage breakdown by detecting a surge voltage, and it is possible to provide a highly reliable power conversion device. become.

  The surge voltage detection means described above detects an increase in surge voltage due to an abnormality in the inductance and current change rate of the inverter main circuit, outputs a fail signal from the surge voltage abnormality determination unit, and based on the fail signal. Display on the operation panel and control equipment of the motor controller. For example, when applied to an electric vehicle, a surge voltage abnormality can be notified to a motor control device operator or a maintenance worker by, for example, turning on a warning lamp on an internal panel.

  In addition, by detecting surge voltage abnormalities in the small current region at an early stage, by implementing surge voltage suppression means such as applying torque limitation or switching gate resistance, avoiding overvoltage application to the semiconductor switching element Since the motor control system can be continuously driven, a highly reliable power conversion device can be provided.

  As an application range of the present invention, in addition to an automobile using a permanent magnet synchronous motor drive system exemplified in the text, it has a power conversion circuit composed of semiconductor switching elements such as an elevator, a compressor, etc. Sometimes, a system in which a surge voltage is applied to the semiconductor switching element and a device using the system are conceivable.

DESCRIPTION OF SYMBOLS 1 Motor 2 Inverter circuit 3 Current sensor 4 Motor control circuit 5 Gate drive circuit 6 Surge voltage detection means 7 Current command generation part 8 Current control part 9 Zener diode 10 Backflow prevention diode 11 Detection resistor 12 Amplification circuit 13 Latch circuit 14 Insulation transmission Element 15 Gate resistance A
16 Gate resistance B
17 Gate resistance changeover switch 18 Zener diode 1 Vz1
19 Zener diode 2 Vz2
20 Zener diode 3 Vz3
21 Zener diode 4
22 Zener diode 5
23 Voltage divider resistor A
24 Voltage divider resistor B
25 Peak hold circuit 26 Microcomputer 50 Surge voltage protection area 1
51 Surge voltage protection area 2
52 Surge Voltage Protection Area 3

Claims (11)

An inverter circuit that outputs a three-phase alternating current;
A current sensor for detecting the three-phase alternating current;
A motor control circuit for driving the inverter circuit;
The inverter circuit includes a gate drive circuit that drives a semiconductor switching element that constitutes the inverter circuit based on a PWM signal from the motor control circuit, and a surge voltage detection circuit that detects a surge voltage detection signal,
The motor control circuit includes a current command generation unit that generates and stores a current command value,
The surge voltage detection signal detected by the surge voltage detection circuit is input to the motor control circuit,
Selection means for selecting whether or not to implement a surge voltage suppressing means for suppressing the surge voltage by comparing the current command value from the current command generation unit with a predetermined current command value when the surge voltage detection signal is detected. A power conversion device comprising: The power conversion device according to claim 1,
The motor control circuit has a current command generation unit that generates a current command based on a torque command value from a host controller,
The current command generation unit determines that the surge voltage is abnormal when the current command value at the time when the surge voltage detection signal is detected is equal to or less than a predetermined current value. The power conversion device according to claim 2,
The surge voltage detection circuit has a Zener diode, a diode and a resistor connected in series and connected in parallel between the collector and emitter of the semiconductor switching element or between the drain and source, thereby exceeding a predetermined Zener voltage value. And detecting a Zener current flowing through the Zener diode. The power conversion device according to claim 2,
The surge voltage detection circuit divides and takes in the voltage between the collector and emitter (or drain and source) of the semiconductor switching element by a voltage dividing resistor, and the peak value of the surge voltage applied between the collector and emitter by the peak hold circuit. The power converter characterized by detecting. The power conversion device according to claim 3,
The surge voltage detection circuit includes a detection circuit having different detection levels of surge voltage by connecting a plurality of Zener diodes in series. The power conversion device according to claim 3 or 5,
The surge voltage detection circuit is configured by connecting a single or a plurality of Zener diodes, a diode and a resistor in series, and connecting a plurality of surge voltages in parallel between the collector / emitter or drain / source of a semiconductor switching element. A power conversion device having a detection level. The power conversion device according to any one of claims 1 to 6,
The motor control circuit includes a current command generation unit that generates a current command based on a torque command value from a host controller, and the current command generation unit receives a surge voltage detection signal from the surge voltage detection unit. A power converter that limits a maximum output value of the current command value when The power conversion device according to any one of claims 1 to 6,
The motor control circuit includes a current command generation unit that generates a current command based on a torque command value from a host controller, and the current command generation unit receives a surge voltage detection signal from the surge voltage detection unit. And a feedback control that reduces the current value until the surge voltage becomes a specified value or less. The power conversion device according to any one of claims 1 to 6,
The motor control circuit includes a current command generation unit that generates a current command based on a torque command value from a host controller, and the current command generation unit 7 receives a surge voltage detection signal from the surge voltage detection means. When being done, the generation of the current command value is stopped. The power conversion system according to any one of claims 1 to 9,
The motor control circuit includes a current command generation unit that generates a current command based on a torque command value from a host controller, and the current command generation unit includes an arithmetic processing unit such as a microcomputer, and the surge voltage When the current command value at the time when the detection signal is detected is equal to or less than an arbitrarily defined current value, the motor drive is continued by switching the gate resistance value of the gate drive circuit. apparatus. In a power conversion system including a motor and an inverter,
The power converter includes an inverter circuit that outputs a three-phase alternating current to the motor, a current sensor that detects the three-phase alternating current, and a motor control circuit that drives the inverter circuit. A gate drive circuit for driving a semiconductor switching element constituting the inverter circuit based on a PWM signal from a motor control circuit, and a surge voltage detection circuit for detecting a surge voltage detection signal, the motor control circuit generates a current command value A surge voltage detection signal detected by the surge voltage detection circuit is input to the motor control circuit, and a current from the current command generation unit is detected when the surge voltage detection signal is detected. Surge voltage suppressor that suppresses surge voltage by comparing command value with predetermined current command value Power conversion system characterized in that it comprises a selection means for selecting whether to implementation.