JP2007089335A - Voltage detection method of power switching element and power conversion device using this - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a more highly reliable voltage detection method for surge voltage control and short-circuit protection of power switching elements connected in parallel and a power conversion device using this method. <P>SOLUTION: This device is made up of a power converter comprising a plurality of connected-in-parallel power switching elements 1 each having a high-voltage side terminal 4 and a low-voltage side terminal 5, a control means that controls the control electrode of the power switching elements, and voltage detection circuits structured by connecting in series a plurality of resistors 6, 7 provided between the high-voltage side terminal 4 and the low-voltage side terminal 5 of each power switching element 1. Of the voltage values detected by each voltage detection circuit, the maximum detected voltage value is regarded as the detected voltage value of a plurality of the power switching elements 1 connected in parallel. The control means controls the control electrode of the power switching elements 1 according to the detected voltage value. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a voltage detection method for a power switching element configured by connecting a plurality of devices in parallel and a power conversion device using the same.

  Power converters using power switching elements have expanded their application range as the switching elements have larger capacities and higher speeds. In recent years, switching elements have shifted from current-driven gate elements such as thyristors and GTOs to IGBTs and MOSFETs, which are voltage-controlled gate elements with high controllability.

  The voltage-driven gate element can suppress and control the surge voltage / surge current generated when the element is turned off / turned on by gate control. It is also possible to freely control the slope of the voltage / current during the switching transition period. As an example of this gate control, the device voltage at the turn-off time of the IGBT is detected, and when the device voltage exceeds the set level, the gate current in the ON direction is injected into the gate of the IGBT, the IGBT is re-ignited, and the surge voltage of the IGBT A method for suppressing the above has been proposed (see, for example, Patent Document 1).

Similarly to the above, short circuit protection by gate control is also performed. In this method, when the device voltage exceeds a level that is determined to be short-circuited while the gate is on, it is determined that a short-circuit current is flowing in the IGBT, and the gate voltage value is normally lower than the voltage value when on. . Since the saturation current value of the IGBT is lowered by lowering the on-gate voltage value, the short-circuit current can be limited to this saturation current value. If the short-circuit current is limited to a sufficiently low current value, it is possible to turn off the IGBT without destroying it even when a short-circuit occurs (see Non-Patent Document 1, for example).
Japanese Patent Laying-Open No. 2005-33873 (page 4-5, FIG. 1) "Short-circuit protection of APPLICATION NOTES IGBT", AN-984J, International Rectifier, [Retrieved August 9, 2005], Internet <URL: http://www.irf-japan.com/technical-info/appnotes/ an-984j.pdf>

  The surge voltage suppression shown in Patent Document 1 or the short-circuit protection shown in Non-Patent Document 1 can be performed without problems when the IGBTs are not connected in parallel. However, when a plurality of IGBTs are connected in parallel, there are the following problems.

  Normally, IGBTs connected in parallel are connected by a connection conductor such as copper bus, and an inductance component of the copper bus exists between the IGBTs. Although this inductance component is very small, a voltage is generated in the inductance component of the copper bus due to high di / dt when the IGBT is turned off. In some cases, a large voltage difference occurs between IGBTs connected in parallel due to the difference in inductance component due to the current path and the difference in di / dt due to the switching characteristic difference of the IGBT. Therefore, when IGBTs are used in a multi-parallel connection, there is a possibility that the surge voltage cannot be sufficiently suppressed by suppressing the surge voltage by the gate control only by detecting the element voltage of any one element.

  Similarly, when a short circuit occurs, a voltage difference occurs between the IGBTs connected in parallel due to the inductance component of the copper bus between the IGBTs connected in parallel due to high di / dt due to the short circuit current. For example, it is assumed that a short-circuit current flows directly to one of two IGBTs connected in parallel, and a short-circuit current flows to the other IGBT via a copper bus. At this time, the short-circuit current increases at a constant di / dt until the saturation current of the IGBT is reached, and the IGBT element voltage also increases. However, when the IGBT reaches the saturation current, two IGBT element voltages Is a constant value. If an element voltage at a level at which di / dt is determined to be short-circuited during the rising period can be detected, damage due to short-circuiting to the IGBT can be reduced, and the effect of short-circuit protection by gate control described above can be enhanced. However, the device voltage between them has a di / dt voltage also in the copper bus having an inductance component due to the short-circuit current path, so that a difference occurs in the device voltage between the two IGBTs.

  Therefore, when IGBTs are connected in multiple parallels and applied to a power conversion device, there is a possibility that rapid short-circuit detection cannot be performed only by detecting the element voltage of one element, and the effect of short-circuit protection may not be expected.

  The present invention has been made in view of the above problems, and provides a voltage detection method for a power switching element connected in parallel with higher reliability for surge voltage suppression and short circuit protection, and a power converter using the same. The purpose is to provide.

  In order to achieve the above object, a voltage detection method for a power switching element according to a first invention of the present invention is a power configured by connecting a plurality of power switching elements having a high voltage side terminal and a low voltage side terminal in parallel. A method for detecting a voltage of a power switching element of a converter, comprising: a voltage detection circuit comprising a plurality of resistors connected in series between the high-voltage side terminal and the low-voltage side terminal of each of the power switching elements. The maximum voltage detection value among the voltage detection values detected by each of the voltage detection circuits is set as a detection voltage value of the plurality of power switching elements connected in parallel.

The power converter according to the second aspect of the present invention includes a power converter formed by connecting a plurality of power switching elements having a high-voltage side terminal and a low-voltage side terminal in parallel, and control of the power switching element. Control means for controlling the pole, and a voltage detection circuit comprising a plurality of resistors connected in series between the high-voltage side terminal and the low-voltage side terminal of each of the power switching elements, The voltage detection value that is the maximum value among the voltage detection values detected by the voltage detection circuit is set as the detection voltage value of the plurality of power switching elements connected in parallel, and the control means includes the detection voltage value The control pole of the power switching element is controlled according to the above.

ADVANTAGE OF THE INVENTION According to this invention, it becomes possible to provide the voltage detection method of the switching element for power switching with higher reliability for surge voltage suppression and short circuit protection, and a power converter device using the same.

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

  FIG. 1 is a circuit configuration diagram showing a voltage detection method for a power switching element according to Embodiment 1 of the present invention.

  Flywheel diodes 2A, 2B, and 2C are connected in reverse parallel to IGBTs 1A, 1B, and 1C, respectively, to form an IGBT module. The collector terminals 4A, 4B, and 4C of the IGBT 1A, IGBT 1B, and IGBT 1C are connected to the positive connection conductor 3P, and the emitter terminals 5A, 5B, and 5C of the IGBT 1A, IGBT 1B, and IGBT 1C are connected to the negative connection conductor 3N, The IGBTs 1A, 1B and 1C form a parallel circuit.

  A series circuit of voltage dividing resistors 6A and 7A, voltage dividing resistors 6B and 7B, and voltage dividing resistors 6C and 7C is connected between the collector and emitter of IGBT 1A, IGBT 1B, and IGBT 1C, respectively. The voltage detection signal between the collectors and emitters of the IGBTs 1A, 1B, and 1C is input to the maximum value selection circuit 20. The maximum value selection circuit 20 selects the maximum value of the collector-emitter voltages of the IGBTs 1A, 1B, and 1C as the collector-emitter voltage Vce of the IGBTs 1A, 1B, and 1C connected in parallel.

  As shown, an inductance component exists in the connection conductors 3P and 3N for parallel connection of the IGBT module. This inductance component generates a voltage by di / dt of the short-circuit current when each IGBT is turned off or when a short-circuit occurs. A voltage difference is generated in the collector-emitter voltage of each IGBT due to a difference in di / dt due to a difference in inductance component due to the current path and a switching characteristic difference between the IGBTs.

  When performing surge voltage suppression by gate control or short-circuit protection by gate control, control by the highest element voltage is necessary among IGBTs connected in parallel.

  Therefore, according to the method shown in the first embodiment, voltage dividing resistors are connected to the IGBTs connected in parallel to detect the device voltages of the IGBTs, and the device voltage values are compared to select the maximum value. Thus, the element voltage value for gate control is eliminated, and the influence of the characteristic difference between the connection conductor for parallel connection and each IGBT is eliminated, and the performance of surge voltage suppression and short circuit protection by gate control is greatly improved.

  In the above description, the case where the number of IGBTs connected in parallel is 3 has been described, but it is obvious that the number of parallel connections may be any number of 2 or more. The same applies to the second and subsequent embodiments.

  FIG. 2 is a circuit configuration diagram illustrating a voltage detection method for a power switching element according to a second embodiment of the present invention. In the second embodiment, the same parts as those in the circuit configuration diagram showing the voltage detection method for the power switching device according to the first embodiment shown in FIG. The difference between the second embodiment and the first embodiment is that capacitors 8A and 9A, 8B and 9B, and 8C and 9C are connected in parallel with the voltage detection voltage dividing resistors 6A and 7A, 6B and 7B, and 6C and 7C, respectively. Is a point.

  According to the method shown in the second embodiment, by connecting a capacitor in parallel to each voltage dividing resistor, a storage capacitance in a gate control circuit (not shown) to which the detected element voltage value is input is compensated. It becomes possible. Therefore, it is possible to follow a fast change in the element voltage at the time of switching of the IGBT, and it is possible to further improve the performance of surge voltage suppression and short circuit protection by gate control.

  FIG. 3 is a circuit configuration diagram illustrating a voltage detection method for a power switching element according to a third embodiment of the present invention. In the third embodiment, the same parts as those in the circuit configuration diagram showing the voltage detection method of the power switching element according to the first embodiment shown in FIG. The third embodiment is different from the first embodiment in that the high voltage side voltage detection points of the IGBTs 1A, 1B and 1C are replaced with collector terminals 4A, 4B and 4C which are main terminals of the respective IGBT modules, and the respective IGBT modules. The collector voltage detection terminals 10A, 10B, and 10C are used.

  According to the method of the third embodiment, by connecting the voltage dividing resistor not between the collector terminal and the emitter terminal of the IGBT but between the collector voltage detection terminal and the emitter terminal, the conductor bus and the wire bonding in the IGBT module are connected. It is possible to remove the influence of the inductance component. Therefore, surge voltage suppression and short circuit protection performance by gate control is further improved.

  FIG. 4 is a circuit configuration diagram illustrating a voltage detection method for a power switching element according to a fourth embodiment of the present invention. In the fourth embodiment, the same parts as those in the circuit configuration diagram illustrating the voltage detection method for the power switching element according to the first embodiment shown in FIG. The fourth embodiment is different from the first embodiment in that the low voltage side voltage detection points of the IGBTs 1A, 1B and 1C are replaced with the emitter terminals 5A, 5B and 5C which are main terminals of the respective IGBT modules, and the respective IGBT modules. The auxiliary emitter terminals 11A, 11B, and 10C for gate control are used.

  The auxiliary emitter terminal for gate control is a negative terminal for gate, and unlike the emitter terminal of the main circuit, has an internal wiring structure in which wiring is directly taken out from the vicinity of the IGBT chip on the emitter side.

  According to the voltage detection method of the fourth embodiment, by connecting the voltage dividing resistor between the collector terminal and the auxiliary emitter terminal instead of between the collector terminal and the emitter terminal of the IGBT, the influence of the inductance component of the wiring in the IGBT module is affected. Can be removed. Therefore, similarly to the method of the third embodiment, the performance of surge voltage suppression and short circuit protection by gate control is further improved.

  FIG. 5 is a circuit configuration diagram illustrating a voltage detection method for a power switching element according to a fifth embodiment of the present invention. In FIG. 5, the circuit configuration of the voltage detection unit of the IGBT 1A, which is one element of the IGBTs connected in parallel, is shown, and the other parts are not shown.

  The flywheel diode 2A is connected in reverse parallel to the IGBT 1A, and the collector terminal 4A and emitter terminal 5A of the IGBT module are connected in parallel to other IGBTs not shown. A series circuit of voltage dividing resistors 6A1 and 7A1 is connected between the collector terminal 4A and the emitter terminal 5A, and the collector-emitter voltage Vce detection value 1 is detected from the middle point of the voltage dividing resistors 6A1 and 7A1, and the maximum value (not shown) It is given to the selection circuit 1.

  Similarly, a series circuit of voltage dividing resistors 6A1 and 7A1 is connected between the collector voltage detecting terminal 10A and the auxiliary emitter terminal 11A, and the collector-emitter voltage Vce detection value 2 is detected from the middle point of the voltage dividing resistors 6A2 and 7A2. Then, it becomes the input of the maximum value selection circuit 2 (not shown).

  As described above, there are connecting conductors and wire bonding between the collector terminal 4A of the IGBT module and the collector terminal 10A for voltage detection, that is, the collector of the IGBT chip in the module, and an inductance component exists. Since this inductance component generates a voltage by di / dt, the detection voltage at the collector terminal 4A is different from the detection voltage at the voltage detection collector terminal 10A. Surge voltage suppression by gate control mainly needs to detect a voltage surge at turn-off, but the current at this time decreases, so the voltage generated in this inductance component due to di / dt is the IGBT chip's voltage. It acts in a direction to lower the voltage at the collector terminal 4A of the module with respect to the collector voltage. The same applies to the emitter side. Therefore, when the surge voltage is suppressed, detection accuracy can be improved by detecting the voltage between the collector voltage detection terminal 10A for measuring the collector voltage of the IGBT chip and the auxiliary emitter 11A.

  Conversely, short-circuit protection by gate control increases the short-circuit current, so that the voltage generated in the inductance component due to di / dt acts to increase the voltage at the collector terminal 4A of the module relative to the collector voltage of the IGBT chip. To do. The same applies to the emitter side. Therefore, at the time of short-circuit protection, if the voltage between the collector terminal 4A and the emitter 5A of the module is detected, it is possible to perform a fast protection operation with higher detection sensitivity.

  As described above, in the fifth embodiment of the present invention, the voltage dividing resistor for suppressing the surge voltage by the gate control is connected between the collector voltage detecting terminal of the IGBT and the auxiliary emitter terminal, and the dividing resistance for the short circuit protection is provided. By connecting a piezoresistor between the collector terminal and the emitter terminal and adopting an element voltage detection method suitable for each control, the influence of the conductor bus in the IGBT module and the inductance component of wire bonding is eliminated with regard to surge voltage suppression. With regard to short circuit protection, it is possible to positively use the voltage generated in the inductance component of the conductor bus and wire bonding in the IGBT module. Therefore, surge voltage suppression and short circuit protection performance by gate control is greatly improved.

  As described in the second embodiment, a capacitor may be connected in parallel with the voltage dividing resistors 6A1 and 7A1 in order to compensate for the storage capacitance in the gate control circuit (not shown) to which the detected element voltage value is input. . The same applies to the voltage dividing resistors 6A2 and 7A2.

  Since the inductance component on the emitter side is smaller than the inductance component on the collector side inside the IGBT module, the low-voltage side detection terminal for the collector-emitter voltage Vce detection value 2 is replaced by an emitter terminal instead of the auxiliary emitter terminal 11A. 5A may be used.

  FIG. 6 is a circuit configuration diagram showing a voltage detection method for a power switching element according to Embodiment 6 of the present invention.

  Flywheel diodes 2A, 2B, and 2C are connected in reverse parallel to IGBTs 1A, 1B, and 1C, respectively, to form an IGBT module. The collector terminals 4A, 4B, and 4C of the IGBT 1A, IGBT 1B, and IGBT 1C are connected to the positive connection conductor 3P, and the emitter terminals 5A, 5B, and 5C of the IGBT 1A, IGBT 1B, and IGBT 1C are connected to the negative connection conductor 3N, The IGBTs 1A, 1B and 1C form a parallel circuit. The IGBTs 1A, 1B and 1C connected to the flywheel diodes 2A, 2B and 2C in reverse parallel and the positive and negative connection conductors 3P and 3N are structurally integrated to form an IGBT unit 30. Yes.

  An intermediate point in the longitudinal direction of the positive side connecting conductor 3A on the IGBT collector side in the IGBT unit 30 is a point P, and the IGBT 1B physically closest to the point P and the point P (in FIG. 7, the IGBT 1B is the closest element) A series circuit of voltage-dividing resistors 6U and 7U for detecting the collector-emitter voltage of the IGBT unit 30 is connected between the emitter terminals 5B. Then, the collector-emitter voltage of the IGBT unit 30 detected at the midpoint of the voltage dividing resistors 6U and 7U is output as a Vce detection value to a gate control unit (not shown).

  A problem with voltage detection during short-circuit protection is how quickly a voltage due to a short-circuit can be detected rather than accuracy. In the case of an IGBT unit configured by connecting a plurality of IGBTs in parallel, it is not necessary to detect the collector-emitter voltage of each IGBT, and it is only necessary to be able to detect at one point where the collector-emitter voltage becomes as high as possible in the entire unit when a short circuit occurs. Further, as described above, the voltage can be detected more effectively by using the voltage generated in the conductor bus in the IGBT module and the inductance component of the wire bonding by the di / dt of the short-circuit current.

  As described above, as the common collector voltage when the IGBT modules connected in parallel are short-circuited, the voltage of the connection conductor for connecting the IGBT module collector terminal is detected, and this is used as the collector voltage when the entire IGBT unit is short-circuited. It becomes possible. However, since the direction and magnitude of the voltage generated in the inductance component of the connection conductor varies depending on the short-circuit path, the intermediate point of the connection conductor is set as the collector voltage detection point in order to minimize the error. On the emitter side, the emitter terminal of the IGBT module closest to the intermediate point of the connection conductor is used as the emitter voltage detection point.

  In the sixth embodiment of the present invention, the collector-emitter voltage detection for short-circuit protection of the IGBT unit in which the IGBT modules are connected in parallel, the voltage dividing resistor is connected to the intermediate point of the connecting conductor for connecting the IGBT collector terminal, By connecting only one circuit between the emitter terminals of the IGBT module closest to the intermediate point, the performance of short circuit protection can be improved, and the size of the main circuit and gate circuit can be reduced.

  Also in the sixth embodiment, as described in the second embodiment, in order to compensate for the storage capacitance in the gate control circuit (not shown) to which the detected element voltage value is input, the voltage dividing resistors 6B and 7B are connected in parallel. A capacitor may be connected to the capacitor.

  In the above, the intermediate point of the positive connection conductor is point P, but conversely, the intermediate point of the negative connection conductor is point P, and the voltage between the collector terminal of the IGBT closest to point P and the point P is the point P. You may make it detect.

  FIG. 7 is a block configuration diagram of a power conversion device using a voltage detection method for a power switching element according to a seventh embodiment of the present invention. The power converter 40 is applied by connecting a power switching element such as an IGBT in parallel to the conversion circuit, and is configured to convert a direct current from a direct current power source into an alternating current and link it with the power supply system, for example.

  The element voltage of the parallel connection portion of the IGBT in the power converter 40 is determined by the method described in the fifth embodiment of FIG. 5 and the Vce detection value 1 and Vce after the maximum value is selected by the maximum value selection circuit. Detection value 2 is obtained.

  The Vce detection value 1 is determined by the short circuit determination circuit 41 to determine whether or not it is equal to or greater than a predetermined value when the IGBT is on. If this is equal to or greater than the predetermined value, it is determined as a short circuit condition and the short circuit protection gate control circuit 42 reduces the gate voltage. After that, turn off for protection.

  Further, the Vce detection value 2 is determined by the surge determination circuit 43 to determine whether it is equal to or greater than a predetermined value when the IGBT starts an off operation. If this is equal to or greater than the predetermined value, it is determined that the surge voltage is excessive, and the surge suppression gate control circuit 44 In order to suppress the surge voltage by supplying a gate current again.

  As described above, it is possible to provide a power converter capable of performing short-circuit protection and surge voltage suppression control using the voltage detection method according to the second embodiment of the present invention.

  In addition, even if it uses the voltage detection method of Example 1, Example 2, Example 3, Example 4 and Example 6 of this invention, the power converter device which can perform a short circuit protection and surge voltage suppression control similarly. It is clear that can be provided. In these cases, since the Vce detection value 1 and the Vce detection value 2 are equal, the Vce detection values input to the short circuit determination circuit 41 and the surge determination circuit 43 are the same.

The circuit block diagram which shows the voltage detection method of the switching element for electric power which concerns on Example 1 of this invention. The circuit block diagram which shows the voltage detection method of the switching element for electric power which concerns on Example 2 of this invention. The circuit block diagram which shows the voltage detection method of the switching element for electric power which concerns on Example 3 of this invention. The circuit block diagram which shows the voltage detection method of the switching element for electric power which concerns on Example 4 of this invention. The circuit block diagram which shows the voltage detection method of the switching element for electric power which concerns on Example 5 of this invention. The circuit block diagram which shows the voltage detection method of the switching element for electric power which concerns on Example 6 of this invention. The block block diagram of the power converter device using the voltage detection method of the switching element for electric power which concerns on Example 7 of this invention.

Explanation of symbols

1A, 1B, 1C IGBT
2A, 2B, 2C Flywheel diode 3P, 3N Connecting conductors 4A, 4B, 4C Collector terminals 5A, 5B, 5C Emitter terminals 6A, 6B, 6C, 6U, 7A, 7B, 7C, 7U Voltage dividing resistors 8A, 8B, 8C , 9A, 9B, 9C Capacitors 10A, 10B, 10C Emitter terminals 11A, 11B, 11C for voltage detection Auxiliary emitter terminal 20 Maximum value selection circuit 30 IGBT unit 40 Power converter 41 Short circuit determination circuit 42 Short circuit protection gate control circuit 43 Surge determination Circuit 44 Surge suppression gate control circuit

Claims (12)

A voltage detection method for a power switching element of a power converter configured by connecting a plurality of power switching elements having a high-voltage side terminal and a low-voltage side terminal in parallel,
A voltage detection circuit comprising a plurality of resistors connected in series between the high-voltage side terminal and the low-voltage side terminal of each of the power switching elements;
The voltage switching value that is the maximum value among the voltage detection values detected by each of the voltage detection circuits is set as a detection voltage value of the plurality of power switching elements connected in parallel. Voltage detection method for the element. The high voltage side terminal is
2. The voltage detection method for a power switching element according to claim 1, wherein the voltage detection terminal is a high voltage side voltage detection terminal for the power switching element provided in the module for the power switching element. The low-voltage side terminal is
2. The voltage detection method for a power switching element according to claim 1, wherein the power switching element is a low-voltage side control terminal for the power switching element provided in the module for the power switching element. A method for detecting a voltage of a power switching element of a power converter configured by connecting in parallel a plurality of power switching elements having a plurality of high-voltage side terminals and at least one low-voltage side terminal,
A first voltage detection circuit comprising a plurality of resistors connected in series between the first high-voltage side terminal and the low-voltage side terminal of each of the power switching elements;
A second voltage detection circuit comprising a plurality of resistors connected in series between the second high-voltage side terminal and the low-voltage side terminal of each of the power switching elements;
Short-circuit protection of the power switching element unit in which a plurality of power switching elements are connected in parallel to the voltage detection value that is the maximum value among the voltage detection values detected by each of the first voltage detection circuits. Detection voltage value for
Among the voltage detection values detected by each of the second voltage detection circuits, the voltage detection value that is the maximum value is used as the surge voltage of the power switching element unit in which a plurality of power switching elements are connected in parallel. A voltage detection method for a switching element for power, wherein the detection voltage value for suppression control is used. The high voltage side terminal includes a high voltage side voltage detection terminal and a high voltage side main terminal for the power switching element provided in the module for the power switching element,
The high voltage side terminal for the first voltage detection circuit is the high voltage side main terminal;
5. The voltage detection method for a power switching element according to claim 4, wherein the high voltage side terminal for the second voltage detection circuit is the high voltage side voltage detection terminal. The low voltage side terminal comprises a low voltage side control terminal and a low voltage side main terminal for the power switching element provided in the module for the power switching element,
The high-voltage side terminal for the first voltage detection circuit is the low-voltage side main terminal;
5. The voltage detection method for a power switching element according to claim 4, wherein the low voltage side terminal for the second voltage detection circuit is the low voltage side control terminal. In the voltage detection method of the power switching element unit, in which a plurality of power switching elements are arranged in parallel in the longitudinal direction of the connection conductors via the positive and negative connection conductors,
Between the intermediate point of the positive connection conductor and the low-voltage side terminal of the power switching element closest to the intermediate point, or the intermediate point of the negative connection conductor, and the power closest to the intermediate point A voltage detection circuit comprising a plurality of resistors connected in series between the high voltage side terminals of the switching element is provided.
A voltage detection method for a power switching element, wherein the voltage detection value of the voltage detection circuit is set as a detection voltage value of the plurality of power switching elements connected in parallel.   The voltage detection method for a power switching element according to any one of claims 1 to 7, wherein a capacitor is connected in parallel to each resistor of the voltage detection circuit. A power converter formed by connecting a plurality of power switching elements having a high-voltage side terminal and a low-voltage side terminal in parallel;
Control means for controlling a control pole of the power switching element;
A voltage detection circuit comprising a plurality of resistors connected in series between the high-voltage side terminal and the low-voltage side terminal of each of the power switching elements;
The voltage detection value that is the maximum value among the voltage detection values detected by each of the voltage detection circuits is a detection voltage value of the plurality of power switching elements connected in parallel,
The control means includes
A power conversion apparatus, wherein a control pole of the power switching element is controlled in accordance with the detected voltage value. A power converter formed by connecting in parallel a plurality of power switching elements having a high-voltage side main terminal, a high-voltage side voltage detection terminal, a low-voltage side main terminal, and a low-voltage control pole terminal;
Control means for controlling a control pole of the power switching element;
A first voltage detection circuit comprising a plurality of resistors connected in series between the high-voltage side main terminal and the low-voltage side terminal or the low-voltage control electrode terminal of each power switching element;
A second voltage detection circuit comprising a plurality of resistors connected in series between the high-voltage side voltage detection terminal and the low-voltage side terminal or the low-voltage control pole terminal of each of the power switching elements; Equipped,
Among the voltage detection values detected by each of the first voltage detection circuits, a voltage detection value that is the maximum value is set as a first detection voltage value of the plurality of power switching elements connected in parallel.
The voltage detection value that is the maximum value among the voltage detection values detected by each of the second voltage detection circuits is set as a second detection voltage value of the plurality of power switching elements connected in parallel.
The control means includes
Controlling the control pole of the power switching element to perform a short circuit protection operation according to the first detection voltage value;
A power conversion apparatus, wherein a control pole of the power switching element is controlled so as to perform a surge voltage suppressing operation according to the second detection voltage value. A power switching element unit in which a plurality of power switching elements are arranged in parallel in the longitudinal direction of the connection conductors via positive and negative connection conductors;
Control means for controlling a control pole of the power switching element;
Between the intermediate point of the positive connection conductor and the low voltage side terminal of the power switching element closest to the intermediate point of the negative connection conductor, or the intermediate point of the negative connection conductor and the positive side A voltage detection circuit comprising a plurality of resistors connected in series between the high-voltage side terminals of the power switching element closest to the midpoint of the connection conductor of
The control means includes
A power conversion apparatus, wherein a control pole of the power switching element is controlled in accordance with a detection voltage value of the voltage detection circuit. The power converter according to any one of claims 9 to 11, wherein a capacitor is connected in parallel to each resistor of the voltage detection circuit.

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