JP5241421B2 - Power converter - Google Patents

Description

  The present invention relates to a power conversion device including a plurality of switching elements.

  Power conversion devices using high-speed semiconductor switching elements such as insulated gate bipolar transistors (IGBTs) are used in various fields. A snubber circuit is connected to suppress the jumping voltage during switching of such a high-speed semiconductor switching element. There are several types of snubber circuits, as described in Non-Patent Document 1, but a rechargeable CDR snubber circuit having a relatively small loss and an effect of suppressing a jumping voltage is often used.

  When the rechargeable CDR snubber circuit is connected to the IGBT on the positive side of the main circuit, a series circuit of a snubber capacitor whose one end is connected to the collector of the IGBT and a snubber diode whose cathode is connected to the emitter of the IGBT (hereinafter, referred to as “rechargeable CDR snubber circuit”). The snubber module is connected in parallel to the IGBT, and the connection point between the snubber capacitor and the snubber diode and the negative side of the main circuit are connected via a snubber resistor. The snubber capacitor of the rechargeable CDR snubber circuit is charged in advance to a voltage value equivalent to the power supply, and when the jumping voltage at the time of switching exceeds the charging voltage, the snubber diode is turned on to suppress the voltage rise. Since only the amount of the jumping voltage is consumed by the snubber resistor, the power consumption by the snubber resistor is small and suitable for a device that switches at a relatively high frequency. However, since the heat is generated by the snubber resistor even if the power consumption is small, the size of the device is determined according to the generated heat.

Since the wiring inductance of the snubber module affects the jumping voltage, it must be reduced as much as possible. However, in the case of a snubber resistor, it is only necessary to discharge during switching, and it is not necessary to reduce the wiring inductance so much. Therefore, it is possible to place the snubber resistor at a position away from the IGBT. However, if the snubber resistor is placed at a position away from the IGBT, the wiring becomes longer and more wiring members are required.
JP 2007-151286 A Transistor Technology Special No. 85 "Revision * Introduction to Practical Power Electronics" CQ Publisher

  By the way, a large-capacity semiconductor module has been realized by the advancement of semiconductor technology, but in order to further increase the capacity, a plurality of IGBTs may be connected in parallel. As described above, since the wiring inductance of the snubber module needs to be reduced as much as possible, the snubber module must be connected to each of the IGBTs connected in parallel, and the snubber module cannot be shared. On the other hand, in the case of a snubber resistor, it may be placed at a position away from the IGBT, so it is conceivable to reduce the number of parts by using a common snubber resistor.

  However, if the snubber resistance is simply made common, the snubber capacitors of the snubber modules connected to each of the IGBTs connected in parallel are connected by wiring, and an LC resonance circuit is constituted by the wiring inductance and the snubber capacitor. . For example, in the case where IGBTs connected in parallel as in the configurations shown in FIGS. 18 and 23 of Patent Document 1 connect snubber capacitors of a snubber module to share a snubber resistor, wiring for connecting the snubber capacitors to each other is used. It becomes longer and the wiring inductance becomes larger. Therefore, the snubber resistor needs a resistance value that can suppress the vibration of the LC resonance circuit, and there is a problem that the size of the device increases.

  The problem to be solved by the present invention is to provide a power converter having a structure that can be miniaturized.

In order to solve the above problems, a power converter according to the present invention includes a plurality of switching arms formed using a plurality of switching elements connected in parallel and bridge-connected between a positive electrode and a negative electrode, a power converter apparatus comprising connected in parallel a snubber circuit element, is configured to have a first switching arms one phase are connected in parallel to each other and the second switching arm, snubber circuit, the switching element It has a parallel-connected snubber capacitor and a snubber diode series circuit Ru Tona to a connection point between the first switching arm of the snubber capacitor and the snubber diode, and the snubber capacitor of the second switching arm the a connection point between the snubber diode through the first snubber resistor are connected to each other, the first Between one end and the positive or negative electrode of the snubber resistor, characterized in that you are connected through the second snubber resistor.

  According to the configuration of the present invention, when the switching element on the positive electrode side is explained, the jumping voltage at the time of switching is discharged from the snubber capacitor through the first snubber resistor, the second snubber resistor, and the negative electrode of the main circuit. The current flowing through the snubber resistor is determined by the electric charge accumulated in the snubber capacitor, that is, the snubber capacitor capacity and the jumping voltage, and the generated voltage and the heat generation amount of the snubber resistor vary depending on the snubber resistance value. Here, if an attempt is made to discharge only with the first snubber resistance, the resistance value of the first snubber resistance must be increased, and the amount of heat generation also increases, so the dimensions must be increased. If the size is increased, the first snubber resistor cannot be placed close to the snubber capacitor, and the wiring from the snubber capacitor to the first snubber resistor becomes longer. As described above, when switching elements are connected in parallel to increase the capacitance, an LC resonance circuit is formed by the snubber capacitors connected to each switching element and the wiring inductance of the wiring connecting the snubber capacitors. There is a possibility that it is not possible to suppress the jump voltage. The length of the wiring from the snubber capacitor to the first snubber resistor means that the wiring inductance is increased, and that L of the LC resonance circuit is increased, so that the first resonance is suppressed in order to suppress LC resonance. The snubber resistance must be further increased.

  According to the present invention, since the charge corresponding to the jumping voltage is discharged by the first and second snubber resistors, the resistance value of the first snubber resistor is reduced, and the amount of heat generated during the discharge can be reduced. As a result, the size of the first snubber resistor can be reduced, and the snubber resistor can be arranged closer to the snubber module. Therefore, since the wiring connecting the snubber modules is shortened, the wiring inductance can be reduced, and the resistance value of the first snubber resistance can be reduced, and the device can be miniaturized. Further, the number of wiring members can be reduced. Note that the resistance value of the second snubber resistance can be increased to some extent by separating the second snubber resistance from the device, so that the wiring inductance does not need to be reduced so much.

  In this case, the first snubber resistor is preferably configured by connecting a plurality of resistors in series, and the second snubber resistor is preferably connected to a common connection point of the plurality of resistors.

  Further, it is desirable that each resistance value of the plurality of resistors is smaller than the resistance value of the second snubber resistor. Thereby, the first snubber resistance can be further reduced. However, it is desirable that the first snubber resistance value be set to such an extent that the vibration of the LC resonance circuit can be suppressed.

  ADVANTAGE OF THE INVENTION According to this invention, the power converter device of the structure which can be reduced in size can be provided.

  Hereinafter, the power converter of the present invention is explained based on an example with reference to drawings.

  FIG. 1 shows a schematic configuration example of a three-phase inverter circuit composed of a U phase, a V phase, and a W phase, which is a field of application of the present invention. In this embodiment, an IGBT is used as the semiconductor switching element. The three-phase inverter circuit is formed by bridge-connecting a U-phase switching arm 2, a V-phase switching arm 4, and a W-phase switching arm 6, and is connected in parallel to a smoothing capacitor 8 to drive a load 10 such as a motor. It is like that.

  The switching arm 2 includes a plurality of IGBTs 12, 14, 16, and 18 connected in parallel, the switching arm 4 includes a plurality of IGBTs 20, 22, 24, and 26 connected in parallel, and the switching arm 6 includes a parallel connection. It is composed of a plurality of connected IGBTs 28, 30, 32, and 34. Each IGBT includes a freewheeling diode. A pair of upper and lower switching elements constituting the switching arms 2, 4, 6 are turned on and off repeatedly to supply arbitrary AC power to the load.

  FIG. 2 shows this embodiment. FIG. 2 is a circuit configuration of the switching arm 2 in a circuit in which a snubber circuit is connected in parallel to each IGBT of the three-phase inverter circuit illustrated in FIG. Although the configuration of the switching arm 2 is shown here, the configuration of the switching arms 4 and 6 is the same.

  A positive conductor 40 is connected to the positive terminal 38 of one switching arm 36 connected in parallel to the switching arm 2, a negative conductor 44 is connected to the negative terminal 42, and a positive terminal 48 is connected to the positive terminal 48 of the other switching arm 46. A conductor 50 is connected, and a negative electrode conductor 54 is connected to the negative terminal 52. Further, the smoothing capacitor 8 has a configuration in which two capacitors are connected in parallel, and includes two pairs of positive and negative electrodes, a capacitor conductor 56 is connected at a connection point 57, and a capacitor conductor 58 is connected at a connection point 59. The capacitor conductors 56 and 58 are connected in parallel to the switching arm 2 at connection points 60 and 62. The positive electrode conductor 40 and the negative electrode conductor 44, the positive electrode conductor 50 and the negative electrode conductor 54, the capacitor conductor 56 and the capacitor conductor 58 are magnetically coupled in a laminated structure formed close to each other, and are configured to reduce wiring inductance. ing.

  A snubber module 64 is connected to the IGBT 12 of the switching arm 36, a snubber module 66 is connected to the IGBT 14 in parallel, a snubber module 68 is connected to the IGBT 16 of the switching arm 46, and a snubber module 70 is connected to the IGBT 18 in parallel.

  The snubber modules 64 and 66 are series circuits each including a snubber capacitor 72 and a snubber diode 74, and a snubber diode 76 and a snubber capacitor 78. The snubber diodes 74 and 76 are connected in the forward direction to the negative electrode side. . One end of the snubber capacitor 72 is connected to the positive terminal 38, the other end is connected to one end of the snubber diode 74, and the other end of the snubber diode 74 is connected to one end of the snubber diode 76. The other end of the snubber diode 76 is connected to one end of the snubber capacitor 78, and the other end of the snubber capacitor 78 is connected to the negative terminal 42. A connection point 80 between the snubber module 64 and the snubber module 66 is connected to an AC terminal 82 of the switching arm 36. Each of the snubber modules 68 and 70 includes a series circuit composed of a snubber capacitor 84 and a snubber diode 86, and a series circuit composed of a snubber diode 88 and a snubber capacitor 90, and a connection point 92 between the snubber module 68 and the snubber module 70. Is connected to the AC terminal 94 of the switching arm 46 and has the same configuration as that of the snubber modules 64 and 66, and thus detailed description thereof is omitted. In mounting, the snubber modules 64 and 66 are formed as an integrated snubber module 67, and the snubber modules 68 and 70 are formed as an integrated snubber module 71. The AC terminals 82 and 94 of the switching arms 36 and 46 are connected to a load 10 such as a motor. Usually, since the reactor has a large reactor component, the inductance of this wiring is often connected by a wire. I omitted it.

  Here, the characteristic configuration of the present embodiment will be described. The connection point 96 of the snubber capacitor 72 and the snubber diode 74 of the snubber module 64 and the connection point 98 of the snubber capacitor 84 and the snubber diode 86 of the snubber module 68 are connected to each other at the connection point 100. A snubber resistor 102 is inserted between the connection point 96 and the connection point 100 via wirings 97 and 103, and a snubber is connected between the connection point 98 and the connection point 100 via wirings 99 and 103. A resistor 104 is inserted. Further, the connection point 100 and the connection point 62 are connected via a snubber common resistor 106. Similarly, the connection point 108 of the snubber diode 76 and the snubber capacitor 78 of the snubber module 66 and the connection point 110 of the snubber capacitor 90 and the snubber diode 88 of the snubber module 70 are connected to each other at the connection point 112. A snubber resistor 114 is inserted between the connection point 112 and the connection point 112 via the wirings 109 and 115, and a snubber resistor 116 is inserted between the connection point 110 and the connection point 112 via the wirings 111 and 115. The connection point 112 and the connection point 60 are connected via a snubber common resistor 118. In this embodiment, the snubber resistors 102, 104, 114, 116 have the same resistance value, and the snubber common resistors 106, 118 have the same resistance value. The ratio of the resistance values of the snubber resistor 102 and the snubber common resistor 106 is about 1: 3. The resistance value will be described later. In mounting, the snubber resistors 102 and 114 are formed as an integrated snubber resistor 113, and the snubber resistors 104 and 116 are formed as an integrated snubber resistor 119. The snubber common resistors 106 and 118 are formed as an integrated snubber common resistor 121.

  The operation of the present embodiment configured as described above will be described by taking as an example the case where the IGBT 12 of the switching arm 36 and the IGBT 16 of the switching arm 46 are turned off. The present embodiment is a rechargeable CDR snubber circuit, and the snubber capacitor 72 is always applied with the DC voltage of the smoothing capacitor 8 and operates when the IGBT 12 is turned off and a jump voltage higher than the DC voltage is applied. To do. The charge corresponding to the jumping voltage on the IGBT 12 side is discharged from the snubber capacitor 72 via the snubber resistor 102 and the snubber common resistor 106, and the charge corresponding to the jumping voltage on the IGBT 16 side is discharged from the snubber capacitor 84 to the snubber resistor 104 and the snubber common resistance. It is discharged via 106. Here, if the snubber resistor 102 alone is used to discharge the jumping voltage of the IGBT 12 without providing the snubber common resistor 106, the resistance value of the snubber resistor 102 must be increased, thereby increasing the amount of heat generated. Becomes larger. When discharging, an LC resonance circuit is formed by the snubber capacitors 72 and 84 and the wiring inductances of the wirings 97, 99, and 103, and the jumping voltage may not be suppressed. If the size of the snubber resistor 102 increases, the snubber module Since it cannot be placed close to 64, the length of the wiring 97 becomes longer, the wiring inductance increases, and the resistance value must be further increased. Note that the inductance of the wiring connecting the positive electrode conductor 40, the connection point 60, and the positive electrode conductor 50 is not a problem because it is reduced by the magnetic coupling described above.

  In this embodiment, the jumping voltage of the IGBT 12 can be discharged by the snubber resistors 102 and 106, and since the value of the first snubber resistance is small, the amount of heat generated at the time of discharge can be reduced. As a result, the size of the snubber resistor 102 can be reduced, and the snubber resistor 102 can be disposed closer to the snubber module 64, so that the wiring 97 can be shortened and the wiring inductance can be reduced.

Here, the resistance value of the snubber resistor 102 will be described by taking, as an example, the case where the IGBT 12 and the IGBT 16 are turned off, as in the description of the operation. Assuming that the voltage of the smoothing capacitor 8 is V, since the present embodiment is a rechargeable CDR snubber circuit, the voltage V is constantly applied to the snubber capacitor 72. Here, when the current I flows through the IGBT 12 and turns off, a jumping voltage ΔV that satisfies Equation (1) is obtained.
1/2 · L · I ² = 1/2 · C · ΔV ² (1)

Here, L is the wiring inductance of the wiring connecting the positive terminal 38, the positive conductor 40, and the connection point 60, and C is the capacity of the snubber capacitor 72. From formula (1), it can be seen that the jump voltage ΔV increases as the wiring inductance L and current I increase, and the jump voltage ΔV decreases as the snubber capacitor capacitance C increases. The amount of electric charge C · ΔV that has jumped up is discharged through the snubber resistor 102 and the snubber common resistor 106. At this time, the capacitance Cd of the smoothing capacitor 8 is generally sufficiently larger than the snubber capacitor capacitance C (C << Cd), the wiring inductance L, the connection point 62, the snubber common resistor 106, the connection point 100, and the connection point 96. The snubber wiring inductance Lr of the wiring connecting the two does not significantly affect the discharge of the snubber capacitor 72, and the discharge time constant is approximately the product (C × R) of the snubber capacitor capacitance C and the resistance value R of the snubber resistor 102. Since the voltage of the snubber capacitor 72 is returned to the original V before the next switching, the resistance value of the snubber resistor 102 cannot be so high when the switching frequency is high. On the other hand, if the inductance is large and the capacitor capacity and resistance are small, the snubber resistance 102 cannot be made extremely small. The wiring inductance L is L << Lr because the inductance is reduced by using a laminated conductor as described above in order to suppress the jumping voltage. Further, as described above, since C << Cd, the critical braking resistance value Rc is expressed by Equation (2), and the snubber resistance 102 should have a higher resistance value.
R> Rc = 2 · √ (Lr / C) (2)

  In this embodiment, the wiring 97 that connects the snubber resistor 102 and the snubber module 67 and the wiring 109 that connects the snubber resistor 104 and the snubber module 71 make the snubber resistors 102 and 104 as close as possible to the snubber modules 67 and 71. Thus, the inductance of the circuit composed of the snubber capacitors 72 and 84 and the snubber resistors 102 and 104 can be reduced, and the critical braking resistance value of the LCR circuit can be reduced. Therefore, it is possible to make the resistance value lower than that of the snubber common resistor 106.

  A mounting example of the present embodiment configured as described above will be described with reference to FIGS. 3 is a perspective view of the mounting example of FIG. 2, and FIG. 4 is a side view of the mounting example. Switching arms 36 and 46 each composed of one semiconductor module are installed on a radiator 124 which is a forced air cooling heat sink provided with a cooling air passage 122 under a flat metal 120. Snubber modules 67 and 71 are installed on the switching arms 36 and 46, respectively. Between the snubber modules 67 and 71, a positive conductor 40 and a negative conductor 44, and a positive conductor 50 and a negative conductor 54 are installed. . As will be described later, the negative electrode conductors 44 and 54 are formed by a single wiring conductor 55. The smoothing capacitor 8 is disposed so as to be spaced from the switching arm 46 and the radiator 124 and not interfere with the cooling air passage of the cooling air passage 122, and the capacitor conductors 56 and 58 stacked on the snubber module 71 are positive conductors. 50 and the wiring conductor 55 and the smoothing capacitor 8. Snubber resistors 113 and 119 are installed on the radiator 124 at a distance from the snubber modules 67 and 71, and the snubber common resistor 121 is arranged at a distance from the switching arm 36 and the radiator 124 to cool the cooling air passage 122. Arranged so as not to obstruct the air path. The snubber common resistor 121 has a structure in which the snubber common resistors 106 and 118 are combined into one casing. As shown in FIG. 3, the wiring inductance can be reduced without interfering with the positive conductors 40 and 50 and the negative conductors 44 and 54 at a position far from the switching arms 36 and 46.

  FIG. 5 shows the state of the snubber modules 67 and 71, the positive conductors 40 and 50, and the wiring conductor 55, and FIG. 6 shows the structure of the positive conductors 40 and 50 and the wiring conductor 55. In this mounting example, the insulating plate between the conductors is not shown. The positive conductor 40 connected to the positive terminal 38 of the switching arm 36 is connected to the capacitor conductor 56 at the connection point 60. The positive conductor 50 connected to the positive terminal 48 of the other switching arm 46 is connected to the capacitor conductor 58 at the connection point 62. The wiring conductor 55 is sandwiched between the positive conductors 40 and 50, and the negative conductor 44 connected to the negative terminal 42 of the switching arm 36 and the negative conductor 54 connected to the negative terminal 52 of the switching arm 46 are integrated. The capacitor conductor 58 and the connection point 62 are formed.

  FIG. 7 shows the structure of the capacitor conductors 56 and 58. The capacitor conductor 56 connected to the positive electrode of the capacitor is on the lower side, and the capacitor conductor 58 connected to the capacitor negative electrode is on the upper side. The capacitor conductor 56 is connected to the positive electrode conductor 40 at a connection point 60 at the back of the drawing, and is connected to the positive electrode conductor 50 at a connection point 60 at the front of the drawing. Further, it is connected to the negative electrode conductor 40 at the connection point 60 at the back of the paper, connected to the positive electrode conductor 50 at the connection point 60 in front of the paper, and connected to the smoothing capacitor 8 at the connection point 57. The capacitor conductor 58 is connected to the wiring conductor 55 at the connection point 62 and is connected to the smoothing capacitor 8 at the connection point 59.

  FIG. 8 shows the back side of the snubber modules 67 and 71. Snubber resistors 113 and 119 are installed on the left side of the drawing. The snubber module 67 is connected to the positive terminal 38, the negative terminal 42, and the AC terminal 82 of the switching arm 36, and the snubber module 71 is connected to the positive terminal 48, the negative terminal 52, and the AC terminal 94 of the switching arm 46. The snubber module 67 is connected to the snubber resistor 113 by wirings 97 and 109, and the snubber module 71 is connected to the snubber resistor 119 by wirings 99 and 111.

  As shown in FIG. 3 of the mounting example, the terminals of the switching arms 36 and 46 are located between the positive conductors 40 and 50, the wiring conductor 55, and the snubber modules 67 and 71. Therefore, it is not workable to connect the wiring from the snubber common resistors 106 and 118 there, but workability is improved by connecting to the connection points 60 and 62 as in this mounting example. Therefore, it is possible to shorten the work time when parts are replaced when the machine breaks down, and the downtime of the apparatus can be shortened. Further, the snubber resistors 113 and 119 are attached to the radiator 124 for cooling the heat generated from the switching arms 36 and 46 to dissipate heat, thereby further reducing the size.

  As described above, according to the present embodiment, since the electric charge corresponding to the jumping voltage of the IGBT 12 is discharged by the snubber resistor 102 and the snubber common resistor 106, the resistance value of the snubber resistor 102 becomes small and heat is generated during discharge. The amount can be reduced. Thereby, the size of the snubber resistor 102 can be reduced, and the snubber resistor 102 can be disposed closer to the snubber module 67. Accordingly, since the wirings 97, 103, and 99 connecting the snubber modules 67 and 71 are shortened, the wiring inductance can be reduced, and the resistance value of the snubber resistor 102 can be further reduced to reduce the size of the device. It becomes possible. Further, the number of wiring members can be reduced. The same applies to the other snubber resistors 104, 114, and 116.

  A second embodiment of the present invention is shown in FIGS. Here, only differences from the circuit configuration of the first embodiment will be described. FIG. 9 shows a circuit configuration of this embodiment, and the same components as those in FIG. In the present embodiment, the snubber resistors 102 and 114 are built in the snubber module 67, and the snubber resistors 104 and 116 are built in the snubber module 71 in the same manner. Further, the smoothing capacitor 8 is connected to the positive conductor 130 at the connection point 132, is connected to the negative conductor 134 at the connection point 136, and the load 10 is connected to the wiring 138. Further, the snubber common resistor 106 is connected to the positive terminal 48 of the snubber module 71, and the snubber common resistor 118 is connected to the snubber module 71 through the negative terminal 52.

  FIG. 10 is a perspective view of a mounting example of this embodiment, and FIG. 11 shows the wiring between the positive conductor 130, the negative conductor 134, the load 10 and the snubber resistor in FIG. The figure seen upwards is shown. As shown in FIG. 11, since most of the wiring 115 enters the projection region of the positive conductor 130, the wiring inductance of the circuit composed of the snubber capacitor 78, the snubber resistors 114 and 116, and the snubber capacitor 90 can be reduced. The resistance values of the resistors 114 and 116 can be reduced, the resistance can be reduced, and the snubber module 67 can be incorporated. The same applies to the circuit constituted by the snubber capacitor 72, the snubber resistors 102 and 104, and the snubber capacitor 84. In addition, the length of the wirings 140 and 142 can be reduced by connecting the snubber common resistor 121 to the positive electrode terminal 48 and the negative electrode terminal 52 that are close to each other, and the snubber common resistor 121 is connected to the terminal of the switching arm 46. Since the wirings 140 and 144 and the wirings 142 and 146 are close to each other, the wiring inductance does not increase so much even if the snubber common resistor 121 is disposed far away. In this embodiment, the same effect as that of the first embodiment can be obtained.

  As described above, according to the first and second embodiments, it is possible to provide a power conversion device that is suitable for downsizing of the device, has as few wiring members as possible, and has a structure that does not reduce workability.

  Although two embodiments have been described above, the present invention is not limited to these embodiments and can be applied by appropriately changing the configuration. For example, in this embodiment, IGBT is applied, but it goes without saying that it can be applied to other switching elements. Moreover, although the example of the forced air cooling heat sink was demonstrated as the heat radiator 124 of the mounting example, another structure, for example, a heat pipe type heat radiator etc., may be sufficient.

  In this embodiment, the snubber resistors 102 and 104 are provided on both sides of the connection point 100. However, the snubber resistor 102 may be provided only on one side in some cases. However, it is more preferable to provide it on both sides.

  In FIG. 8, since the snubber resistors 113 and 119 are connected to the left side of the drawing, the wiring can be further shortened by bringing the connection point of each wiring to each snubber resistor to the left side of FIG. In this case, the snubber modules 67 and 71 have different structures.

  The present invention is not limited to the inverter circuit shown in FIG. 1, and can be applied to various power conversion devices including a switching arm and a snubber circuit, such as a converter circuit and a power supply circuit.

1 shows a circuit configuration of a general power converter to which the present invention is applied. 1 shows a circuit configuration of a first embodiment of the present invention. The perspective view of the example of mounting of the 1st example of the present invention is shown. The side view of the example of mounting of the 1st example of the present invention is shown. The connection state of a switching arm, a positive electrode conductor, and a wiring conductor is shown. The structure of a positive electrode conductor and a wiring conductor is shown. The structure of a capacitor conductor is shown. The structure of the back side of a snubber module is shown. The circuit structure of the 2nd Example of this invention is shown. The perspective view of the example of mounting of the 2nd example of the present invention is shown. The figure which looked at the wiring in the 2nd Example of this invention toward the upper direction from the switching arm surface is shown.

Explanation of symbols

12, 14, 16, 18 IGBT
36, 46 Switching arm 64, 66, 67, 68, 70, 71 Snubber module 97, 99, 103, 109, 111, 115 Wiring 102, 104, 114, 116 Snubber resistance 106, 118 Snubber common resistance 113, 119 Snubber resistance 121 Snubber common resistor

Claims (3)

In a power converter comprising a plurality of switching arms formed using a plurality of switching elements connected in parallel and bridge-connected between a positive electrode and a negative electrode, and a snubber circuit connected in parallel to each of the switching elements. ,
A first switching arm and a second switching arm in which one phase is connected in parallel with each other;
Before SL snubber circuit has a snubber capacitor and a snubber diode series circuit Ru Tona connected in parallel with the switching element, a connection point of the snubber capacitor of the first switching arm and the snubber diode, the A connection point between the snubber capacitor and the snubber diode of the second switching arm is connected to each other through a first snubber resistor, and between one end of the first snubber resistor and the positive electrode or the negative electrode , power conversion apparatus characterized by being connected via a second snubber resistor. The power conversion device according to claim 1,
Said first snubber resistor is composed of a plurality of resistors connected in series, said second snubber resistor are connected to a common connection point of said plurality of resistors constituting the first snubber resistor A power conversion device. The power conversion device according to claim 2,
Wherein the resistance values of the plurality of resistors first constituting the snubber resistor is a power conversion device and is smaller than the resistance value of the second snubber resistor.

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