JP2012222741A - Device for driving semiconductor switch elements connected in parallel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drive device that accurately detects whether or not an overcurrent flows through a plurality of semiconductor switch elements connected in parallel.SOLUTION: A drive device 100 includes: a first semiconductor switch element IGBT1; a detection node SO for detecting a current at a second terminal E of the first semiconductor switch element IGBT1; at least one semiconductor switch element IGBT2 connected in parallel with the first semiconductor switch element IGBT1; a drive circuit DR for driving the first semiconductor switch element IGBT1 and the at least one semiconductor switch element IGBT2; a first resistance RG1; and at least one set of resistances RG2, RE2 and at least one set of common mode filters LG2, LE2. A resistance value of RG1 is equal to the sum of a resistance value of RG2 and a resistance value of RE2. A second driving node EO of the drive circuit DR is connected to the second terminal E of the first semiconductor switch element IGBT1 directly without any resistance intervention.

Description

  The present invention relates to a drive device including a plurality of semiconductor switch elements connected in parallel and a drive circuit that drives the plurality of semiconductor switch elements simultaneously.

  A technique for connecting a plurality of semiconductor switch elements in parallel is known from Patent Document 1, Patent Document 2, and the like. The plurality of semiconductor switch elements connected in parallel are used as, for example, a part of an inverter device that converts a direct current into an alternating current and supplies it to a motor (for example, a switching element that constitutes an upper arm of a U phase). it can.

  Patent Document 1 discloses a parallel connection circuit (drive device) of semiconductor switch elements. In FIG. 1 of Patent Document 1, gate drive circuit 4 (drive circuit) drives IGBT 1 (semiconductor switch element) and IGBT 2 simultaneously. . Specifically, in FIG. 1 of Patent Document 1, one of the common mode coils 10 is provided between the gate drive circuit terminal G 0 of the gate drive circuit 4 and the gate terminal G 1 of the IGBT 1, and the gate drive circuit of the gate drive circuit 4. The other of the common mode coils 10 is provided between the terminal E0 and the auxiliary emitter terminal EX of the IGBT1. Further, one of the common mode coils 20 is provided between the gate drive circuit terminal G0 of the gate drive circuit 4 and the gate terminal G2 of the IGBT 2, and the gate drive circuit terminal E0 of the gate drive circuit 4 and the auxiliary emitter terminal EY of the IGBT 2 are connected. The other common mode coil 20 is provided between them.

  3 of patent document 1 discloses the iron core 30 and the iron core 40 instead of the common mode coil 10 and the common mode coil 20. By providing common mode filters such as the common mode coils 10 and 20 and the iron cores 30 and 40, the difference between the turn-off speed of the IGBT 1 and the turn-off speed of the IGBT 2 is absorbed, as shown by the dotted line in FIG. The IGBT 1 and the IGBT 2 can be turned off at the same time.

Patent Document 2 discloses an electronic device (drive device). In FIG. 2 of Patent Document 2, a drive unit 20 (drive circuit) of the electronic device simultaneously drives three IGBTs connected in parallel. Specifically, in FIG. 2 of Patent Document 2, common mode rejection inductances L _D1,1 , L _D2,1 , L _D1,2 , L _D2,2 , L _D1,3 , L _D2,3, etc. A mode filter is provided. Further, common resistance rejection inductances L _D1,1 , L _D1,2 , L _D1,3 on the emitter side of the three IGBTs and the emitter unit R _{E, 1} , R _{E, 2} , R _{E and 3} are provided.

In FIG. 2 of Patent Document 2, the gate resistances R _{G, G} between the common mode rejection inductances L _D2,1 , L _D2,2 , L _D2,3 on the gate side of the three IGBTs and the drive unit 20 are shown _{. 1} , _{RG, 2} , _{RG, 3} are also provided. The emitter resistances R _{E, 1} , R _{E, 2} , R _{E, 3} are set equal to the gate resistances R _{G, 1} , R _{G, 2} , R _{G, 3} , specifically, the nominal gate resistance R of the IGBT. The value is half of _{G and nom} (paragraph [0012] of Patent Document 2).

  FIG. 5 of Patent Document 3 shows a sense terminal 4 connected to the emitter current detection cell of the IGBT 1 and a comparator 10 that detects whether or not the current at the emitter terminal connected to the emitter main cell of the IGBT 1 is an overcurrent. (Detection circuit) is disclosed, and when an overcurrent is detected, the comparator 10 can stop driving the IGBT 1 by the driver circuit 18 (drive circuit).

Japanese Patent Laid-Open No. 08-019246 JP 2006-529066 Gazette Japanese Patent Laid-Open No. 09-064707

  In the parallel connection circuit (driving device) disclosed in Patent Document 1, when a resistance such as a parasitic resistance or a contact resistance exists between the main emitter terminal E1 of the IGBT 1 and the main emitter terminal E2 of the IGBT 2, the common mode coil 10, 20 is magnetically saturated. Specifically, when a voltage difference due to resistance (potential difference on the emitter side) occurs between the main emitter terminal E1 and the main emitter terminal E2, a direct current flows between the auxiliary emitter terminal EX and the auxiliary emitter terminal EX, This direct current causes the common mode coils 10 and 20 to be magnetically saturated.

In the electronic device (driving device) disclosed in Patent Document 2, a DC current as indicated by the dotted line in FIG. 1 of Patent Document 2 causes a common mode rejection inductance L on the emitter side of the three IGBTs in FIG. _{Even if} it flows through _D1,1 , L _D1,2 and L _D1,3 , the magnitude of the direct current decreases due to the presence of the emitter resistors R _{E, 1} , R _{E, 2} , R _{E, 3} . That is, the direct current flowing through the common mode rejection inductances L _D1,1 , L _D1,2 , L _D1,3 in the electronic device (drive device) having the emitter resistors R _{E, 1} , R _{E, 2} , R _{E, 3.} The current is smaller than the direct current when the emitter resistances R _{E, 1} , R _{E, 2} , R _{E, 3} are not provided. Therefore, the emitter resistors R _{E, 1} , R _{E, 2} , R _{E, 3} can suppress the magnetic saturation of the common mode rejection inductances L _D1,1 , L _D1,2 , L _D1,3 .

By the way, when detecting whether or not the current on the emitter side of one IGBT among the three IGBTs in FIG. 2 of Patent Document 2 is an overcurrent, the sense terminal 3 in FIG. A sense terminal is provided in the one IGBT, and a current at the sense terminal can be detected. The current at the sense terminal is affected by the current flowing through the emitter resistor R _E1 . Therefore, the detection accuracy when detecting whether or not the current on the emitter side of the IGBT is an overcurrent is lowered.

  One object of the present invention is to provide a driving device or the like that can accurately detect whether or not an overcurrent flows through a plurality of semiconductor switching elements connected in parallel. Other objects of the present invention will become apparent to those skilled in the art by reference to the following several and preferred embodiments and the accompanying drawings.

  Below, in order to understand the outline | summary of this invention easily, some forms of several forms according to this invention are illustrated.

According to a first aspect of the present invention, a first semiconductor switch element having a first terminal, a second terminal, a third terminal, and a fourth terminal;
A detection node for detecting a current at the fourth terminal representing a current at the second terminal of the first semiconductor switch element;
At least one semiconductor switch element connected in parallel with the first semiconductor element switch, each having a first terminal, a second terminal and a third terminal;
A drive circuit having a first drive node and a second drive node and driving the first semiconductor switch element and the at least one semiconductor switch element;
A first resistor on a first terminal side provided between the first drive node of the drive circuit and the first terminal of the first semiconductor switch element;
One resistance of at least one set of resistors and one of at least one set of common mode filters provided between the first drive node of the drive circuit and the first terminal of the at least one semiconductor switch element. A common mode filter,
The other resistance of the at least one set of resistors and the at least one set of common mode filters provided between the second drive node of the drive circuit and the second terminal of the at least one semiconductor switch element. The other common mode filter,
With
The resistance value of the first resistor is a resistance value of one of the at least one set of resistors corresponding to any one semiconductor switch element of the at least one semiconductor switch element and the resistance value of the first resistor. It is equal to the sum of the resistance value of the other resistor of any one set of resistors,
The second drive node of the drive circuit is directly connected to the second terminal of the first semiconductor switch element without any resistance, and connected in parallel. Related to the driving device.

  The resistance value of the first resistor on the first terminal side provided between the first drive node of the drive circuit and the first terminal of the first semiconductor switch element is the same as that of the first drive node of the drive circuit. The resistance value of the resistor on the first terminal side provided between the first terminal of at least one semiconductor switch element may not be equal. Even in such a case, the drive circuit can drive all the semiconductor switch elements at the same time by adjusting the resistance value between each semiconductor switch element and the drive circuit. At this time, only the first resistor on the first terminal side of the first semiconductor element switch element is provided between the first semiconductor element switch element and the drive circuit, while the first semiconductor switch element The two terminals and the drive circuit are directly connected, and no resistor is provided between the first semiconductor element switch element and the drive circuit on the second terminal side of the first semiconductor switch element. Also good. Therefore, when the current at the fourth terminal representing the current at the second terminal of the first semiconductor switch element is detected at the detection node, the detection accuracy can be increased.

In the first aspect, the at least one semiconductor switch element may include a second semiconductor switch element and a third semiconductor switch element.
The at least one set of resistors may include a first set of resistors corresponding to the second semiconductor switch element and a second set of resistors corresponding to the third semiconductor switch element,
The at least one set of common mode filters includes a first set of common mode filters corresponding to the second semiconductor switch elements, and a second set of common mode filters corresponding to the third semiconductor switch elements. May have,
The resistance value of the first resistor is a resistance value of one resistance of the first set of resistors corresponding to the second semiconductor switch element and a resistance value of the other resistance of the first set of resistors. May be equal to the sum of
The resistance value of the first resistor is a resistance value of one resistance of the two sets of resistors corresponding to the third semiconductor switch element and a resistance value of the other resistance of the second set of resistors. It may be equal to the added value.

  Thus, the resistance value between the first semiconductor switch element and the drive circuit, the resistance value between the second semiconductor switch element and the drive circuit, and between the third semiconductor switch element and the drive circuit The resistance value can be adjusted. Thereby, the drive circuit can drive the first semiconductor switch element, the second semiconductor switch element, and the third semiconductor switch element simultaneously.

  Those skilled in the art will readily understand that each of the forms according to the present invention can be modified without departing from the spirit of the present invention.

1 shows a schematic configuration diagram of a drive device for semiconductor switch elements connected in parallel according to the present invention. FIG. 2 shows a gate wiring of the driving device of FIG. 2 shows a sub-emitter wiring of the driving device of FIG. 2 shows a main emitter wiring of the driving device of FIG. The collector wiring of the drive device of FIG. 1 is shown. The equivalent block diagram of the drive device which is not provided with a common mode filter is shown. The equivalent block diagram of a drive device provided with a common mode filter is shown. An example of a structure of a drive circuit including a detection circuit is shown. The modification of the drive device of FIG. 1 is shown.

  The preferred embodiments described below are used to facilitate an understanding of the present invention. Accordingly, those skilled in the art should note that the present invention is not unduly limited by the embodiments described below.

1. Drive device
1.1. Configuration FIG. 1 shows a schematic configuration diagram of a drive device for semiconductor switch elements connected in parallel according to the present invention. As shown in FIG. 1, the driving apparatus 100 includes an IGBT 1, and an IGBT 2 and an IGBT 3 that are connected in parallel to the IGBT 1. In the example of FIG. 1, the IGBT 1 represents an IGBT (Insulated Gate Bipolar Transistor), but may be replaced with, for example, an FET (Field Effect Transistor) or the like, and the IGBT 1 may be a semiconductor switch element. The same applies to IGBT2 and IGBT3. Hereinafter, in this specification, IGBT1, IGBT2, and IGBT3 are referred to as a first semiconductor switch element IGBT1, a second semiconductor switch element IGBT2, and a third semiconductor switch element IGBT3, respectively. Note that the driving device 100 may omit the third semiconductor switch element IGBT3 or may include other semiconductor switch elements. In other words, the number of semiconductor switch elements connected in parallel may be two or more.

  In the example of FIG. 1, the first semiconductor switch element IGBT1 has a gate terminal G (first terminal), an emitter terminal E (second terminal), and a collector terminal C (third terminal). The first semiconductor switch element IGBT1 further has an emitter sense terminal S (fourth terminal), and the current at the emitter sense terminal S represents the current at the emitter terminal E and the current at the emitter terminal E. Smaller than. The driving device 100 includes a detection node SO for detecting a current at an emitter sense terminal S (fourth terminal) that represents a current at an emitter terminal E (second terminal) of the first semiconductor switch element IGBT1. be able to. The detection node SO can be connected to a detection circuit (not shown), and when a current exceeding a threshold value (overcurrent) is detected by the detection circuit, the drive circuit DR described later includes a semiconductor switch connected in parallel. The driving of the elements IGBT1, IGBT2, IGBT3 can be stopped. The drive circuit DR may incorporate such a detection circuit. In this case, the detection node SO may be connected to the drive circuit DR.

  The second semiconductor switch element IGBT2 also has a gate terminal G (first terminal), an emitter terminal E (second terminal), and a collector terminal C (third terminal), and the third semiconductor switch element IGBT3 also A gate terminal G (first terminal), an emitter terminal E (second terminal), and a collector terminal C (third terminal). The gate terminal G of the first semiconductor switch element IGBT1 is connected to the gate terminals G and G of the second and third semiconductor switch elements IGBT2 and IGBT3 by a gate wiring (see also FIG. 2) as shown in FIG. Is done. The emitter terminal E of the first semiconductor switch element IGBT1 is connected to the emitter terminals E and E of the second and third semiconductor switch elements IGBT2 and IGBT3 by an emitter wiring as shown in FIG.

  In the example of FIG. 1, the emitter wiring is distinguished by the first divided node ND1, the second divided node ND2, and the third divided node ND3, and the sub-emitter wiring on the drive circuit DR side (left side) (also shown in FIG. 3). And a main emitter wiring (see also FIG. 4) on the second output node N side (right side). In other words, the emitter terminals E, E, E of the first, second, and third semiconductor switch elements IGBT1, IGBT2, IGBT3 are connected to the drive circuit DR by sub-emitter wiring, while the first, second, and second Emitter terminals E, E, E of the three semiconductor switch elements IGBT1, IGBT2, IGBT3 are connected to the second output node N by main emitter wiring.

  The collector terminal C of the first semiconductor switch element IGBT1 is a collector wiring (see also FIG. 5) as shown in FIG. 1, and the collector terminals C and C of the second and third semiconductor switch elements IGBT2 and IGBT3. Connected.

  FIG. 2 shows the gate wiring of the driving device 100 of FIG. In the example of FIG. 2, the gate wiring has a first gate wiring portion, a second gate wiring portion, and a third gate wiring portion. The first gate wiring portion has a gate resistor RG1 provided between the first drive node GO of the drive circuit DR and the gate terminal G of the first semiconductor switch element IGBT1. The second gate wiring portion includes a gate resistor RG2 and a common mode coil LG2 provided between the first drive node GO and the gate terminal G of the second semiconductor switch element IGBT2. The third gate wiring portion includes a gate resistor RG3 and a common mode coil LG3 provided between the first drive node GO and the gate terminal G of the third semiconductor switch element IGBT3. A common gate resistance RGC is provided in a common portion of the first gate wiring portion, the second gate wiring portion, and the third gate wiring portion, but the common gate resistance RGC may be omitted.

  In the example of FIG. 2 or the example of FIG. 1, the gate resistor RG2 and the gate resistor RG3 are arranged on the first drive node GO side, and the common mode coil LG2 and the common mode coil LG3 are arranged on the gate terminal G side. Yes. However, the gate resistor RG2 and the gate resistor RG3 may be disposed on the gate terminal G side, and the common mode coil LG2 and the common mode coil LG3 may be disposed on the first drive node GO side. For example, one end of the gate resistor RG2 may be connected to the gate G of the second semiconductor switch element IGBT2, and the other end of the gate resistor RG2 may be connected to one end of the common mode coil LG2. The other end of LG2 may be connected to the first drive node GO via a common gate resistance RGC.

  FIG. 3 shows the sub-emitter wiring of the driving device 100 of FIG. In the example of FIG. 2, the sub-emitter wiring includes a first sub-emitter wiring portion, a second sub-emitter wiring portion, and a third sub-emitter wiring portion. The first sub-emitter wiring portion has no emitter resistance. That is, no emitter resistance is provided between the second drive node EO of the drive circuit DR and the emitter terminal E (first divided node ND1) of the first semiconductor switch element IGBT1. The second sub-emitter wiring portion includes an emitter resistor RE2 and a common mode coil LE2 provided between the second drive node EO and the emitter terminal E (second divided node ND2) of the second semiconductor switch element IGBT2. Have. The third sub-emitter wiring portion includes an emitter resistor RE3 and a common mode coil LE3 provided between the second drive node EO and the emitter terminal E (third divided node ND3) of the third semiconductor switch element IGBT3. Have.

  In the example of FIG. 3 or FIG. 1, the emitter resistor RE2 and the emitter resistor RE3 are arranged on the second drive node EO side, and the common mode coil LE2 and the common mode coil LE3 are arranged on the emitter terminal E side. Yes. However, the emitter resistor RE2 and the emitter resistor RE3 may be disposed on the gate terminal E side, and the common mode coil LE2 and the common mode coil LE3 may be disposed on the second drive node EO side. For example, one end of the emitter resistor RE2 may be connected to the emitter E of the second semiconductor switch element IGBT2, and the other end of the emitter resistor RG2 may be connected to one end of the common mode coil LE2. The other end of LG2 may be connected to the second drive node EO.

  The direct current flowing through the common mode coil LE2 and the common mode coil LE3 is generated by a potential difference generated between the emitters E, E, E of the semiconductor switch elements IGBT1, IGBT2, IGBT3. The emitter resistor RE2 and the emitter resistor RE3 are Magnetic saturation of the common mode coil LE2 and the common mode coil LE3 can be suppressed.

  FIG. 4 shows the main emitter wiring of the driving device 100 of FIG. In the example of FIG. 4, the main emitter wiring has a first main emitter wiring portion, a second main emitter wiring portion, and a third main emitter wiring portion. The first main emitter wiring portion includes an emitter terminal E (first divided node ND1) of the first semiconductor switch element IGBT1 and an emitter terminal E (second divided node ND2) of the second semiconductor switch element IGBT2. It has a wiring resistance RN1 such as a parasitic resistance provided therebetween. The second main emitter wiring portion includes an emitter terminal E (second divided node ND2) of the second semiconductor switch element IGBT2 and an emitter terminal E (third divided node ND3) of the third semiconductor switch element IGBT3. It has a wiring resistance RN2 such as a parasitic resistance provided therebetween. The third main emitter wiring portion has a wiring resistance RN3 such as a parasitic resistance provided between the emitter terminal E (third divided node ND3) of the third semiconductor switch element IGBT3 and the second output node N. . The main emitter wiring may be called an output line, a bus line, or the like. When the main emitter wiring becomes long, it has wiring resistances RN1, RN2, and RN3. The main emitter wiring is not limited to the example of FIG. 4 and may be, for example, a Y-connection type wiring. The wiring resistances RN1, RN2, and RN3 have parasitic resistances that come close to the divided nodes ND1, ND2, and ND3. May be included.

  FIG. 5 shows the collector wiring of the driving device 100 of FIG. In the example of FIG. 5, the collector wiring includes a first collector wiring portion, a second collector wiring portion, and a third collector wiring portion. The first collector wiring portion has a wiring resistance RP1 such as a parasitic resistance provided between the first output node P and the collector terminal C of the first semiconductor switch element IGBT1. The second collector wiring portion has a wiring resistance RP2 such as a parasitic resistance provided between the collector terminal C of the first semiconductor switch element IGBT1 and the collector terminal C of the second semiconductor switch element IGBT2. The third collector wiring portion has a wiring resistance RP3 such as a parasitic resistance provided between the collector terminal C of the second semiconductor switch element IGBT2 and the collector terminal C of the third semiconductor switch element IGBT3. The collector wiring may be called an output line, a bus line, or the like. When the collector wiring becomes longer, it has wiring resistances RP1, RP2, and RP3. The collector wiring is not limited to the example of FIG. 5, and may be, for example, a Y-connection wiring.

  In the example of FIG. 1, the drive device 100 includes a drive circuit DR that drives semiconductor switch elements IGBT1, IGBT2, and IGBT3 connected in parallel. The drive circuit DR has a first drive node GO and a second drive node EO. The drive circuit DR generates a predetermined voltage between the first drive node GO and the second drive node EO, and the predetermined voltage includes the resistance of the gate wiring and the resistance of the sub-emitter wiring and two sets of common modes. The voltage is reflected on the voltage (gate voltage) between the gate terminal G and the emitter terminal E of each semiconductor switch element IGBT1, IGBT2, IGBT3 via the coil. How the predetermined voltage is reflected in the gate voltage will be described later in “1.3. Gate voltage”.

  In the example of FIG. 1, the resistance value of the wiring (the first gate wiring portion and the first sub-emitter wiring portion excluding the common portion) between the first semiconductor switch element IGBT1 and the drive circuit DR is the gate resistance RG1. (When a common part is considered, the resistance value of the common gate resistor RGC and the resistance value of the gate resistor RG1 are added). Here, it is assumed that the wiring resistance of the first gate wiring portion and the wiring resistance of the first sub-emitter wiring portion are negligibly small. In other words, when these wiring resistances cannot be ignored, the resistance value of the gate resistance RG1 can be defined by a value including these wiring resistances.

  The resistance value of the wiring (the second gate wiring portion and the second sub-emitter wiring portion excluding the common portion) between the second semiconductor switch element IGBT2 and the drive circuit DR is the gate resistance RG2 (one set of resistance values). Resistance value (one of the resistance values of the first and second resistance values) (when the common part is considered, the resistance value of the common gate resistance RGC and the resistance value of the gate resistance RG2) and the resistance value of the emitter resistance RE2 (one set of resistances) It can be expressed by a value obtained by adding the other resistance value). Here, it is assumed that the wiring resistance of the second gate wiring portion and the wiring resistance of the second sub-emitter wiring portion are negligibly small. Further, it is assumed that the internal resistance of the common mode coil LG2 and the internal resistance of the common mode coil LE2 are small enough to be ignored. In other words, when these wiring resistance and internal resistance cannot be ignored, the resistance value of the gate resistance RG2 and the resistance value of the emitter resistance RE2 can be defined by values including these wiring resistance and internal resistance.

  The resistance value of the wiring (the third gate wiring portion and the third sub-emitter wiring portion excluding the common portion) between the third semiconductor switch element IGBT3 and the drive circuit DR is the gate resistance RG3 (one set of resistance values). Resistance value (one of the resistance values of the first and second resistance values) (when the common part is considered, the resistance value of the common gate resistance RGC and the resistance value of the gate resistance RG3) and the resistance value of the emitter resistance RE3 (one set of resistances) It can be expressed by a value obtained by adding the other resistance value). Here, it is assumed that the wiring resistance of the third gate wiring portion and the wiring resistance of the third sub-emitter wiring portion are small enough to be ignored. Further, it is assumed that the internal resistance of the common mode coil LG3 and the internal resistance of the common mode coil LE3 are small enough to be ignored. In other words, when these wiring resistance and internal resistance cannot be ignored, the resistance value of the gate resistance RG3 and the resistance value of the emitter resistance RE3 can be defined by values including these wiring resistance and internal resistance.

  In the example of FIG. 1, the resistance value (RG1) of the wiring between the first semiconductor switch element IGBT1 and the drive circuit DR is the resistance value of the wiring between the second semiconductor switch element IGBT2 and the drive circuit DR ( Equal to RG2 + RE2). In addition, the resistance value (RG1) of the wiring between the first semiconductor switch element IGBT1 and the drive circuit DR is also the resistance value (RG3 + RE3) of the wiring between the third semiconductor switch element IGBT3 and the drive circuit DR. equal. Thus, the resistance value of the wiring between each of the semiconductor switch elements IGBT1, IGBT2, and IGBT3 and the drive circuit DR is set to the same value.

  When considering the common portion, in the example of FIG. 1, the resistance value (RG1 + RGC) of the wiring between the first semiconductor switch element IGBT1 and the drive circuit DR is the same as the second semiconductor switch element IGBT2 and the drive circuit DR. It is equal to the resistance value (RG2 + RGC + RE2) of the wiring between them. Further, the resistance value (RG1 + RGC) of the wiring between the first semiconductor switch element IGBT1 and the drive circuit DR is also the resistance value (RG3 + RGC + RE3) of the wiring between the third semiconductor switch element IGBT3 and the drive circuit DR. equal. The resistance value is set so as to satisfy RG1 = RG2 + RE2 = RG3 + RE3 with or without considering the common part.

1.2. Common Mode Filter FIG. 6 shows an equivalent configuration diagram of a drive device that does not include a common mode filter. First, the operation when the driving apparatus 100 of FIG. 1 does not include common mode filters such as the common mode coils LE2, LE3, LG2, and LG3 will be described, and then the role of the common mode filter will be described. In the example of FIG. 6, it is assumed that the voltage between the first drive node GO and the second drive node EO changes, for example, from 0 [V] to 15 [V]. That is, it is assumed that a pulse signal having an amplitude of 15 [V] is applied between the first drive node GO and the second drive node EO. When the voltage between the first drive node GO and the second drive node EO changes from, for example, 0 [V] to 15 [V], all the semiconductor switch elements IGBT1, IGBT2, and IGBT3 are turned on from the off state. Assume that the state is switched. At this time, each semiconductor switch element IGBT1, IGBT2, IGBT3 can be represented by an equivalent capacitor as shown in FIG.

  In the example of FIG. 6, it is assumed that the gate resistor RG1 has a resistance value of, for example, 18 [Ω], the gate resistor RG2 has a resistance value of, for example, 10 [Ω], and the gate resistor RG3 is For example, it is assumed that the resistance value is 10 [Ω], and the gate resistance RGC is assumed to have a resistance value of 5 [Ω], for example. Further, it is assumed that the emitter resistor RE2 has a resistance value of, for example, 8 [Ω], and the emitter resistor RE3 has a resistance value of, for example, 8 [Ω]. Thus, each resistance value (10 [Ω]) of the gate resistances RG2 and RG3 is smaller than the resistance value (18 [Ω]) of the gate resistance RG1. Therefore, each gate current (for example, 0.5 [A]) of the semiconductor switch elements IGBT2, 3 is larger than the gate current (for example, 0.28 [A]) of the first semiconductor switch element IGBT1. On the emitter side, since the resistance of the first sub-emitter wiring portion (wiring between the second drive node EO and the emitter terminal of the first semiconductor switch element IGBT1) is zero, all the gate currents (for example, 1.28) [A] = 0.28 + 0.5 + 0.5 [A]) is released to the emitter side of the first semiconductor switch element IGBT1. As a result, with respect to each semiconductor switch element IGBT1, IGBT2, IGBT3, the voltage between the gate terminal and the emitter terminal (gate voltage) is not set to the same value, and all the semiconductor switch elements IGBT1, IGBT2, IGBT3 are simultaneously turned on. Not.

  On the other hand, as shown in FIG. 1, when the driving apparatus 100 includes common mode filters such as common mode coils LE2, LE3, LG2, and LG3, all the semiconductor switch elements IGBT1, IGBT2, and IGBT3 are simultaneously turned on. . Hereinafter, a set of common mode coils including, for example, the common mode coil LG2 and the common mode coil LE2 will be described. In the example of FIG. 1, it is assumed that there is a potential difference of, for example, 2 [V] at both ends of the common mode coil LG2 (one common mode coil of a set of common mode coils). At this time, a potential difference of, for example, 2 [V] is also generated at both ends of the common mode coil LE2 (the other common mode coil of the set of common mode coils).

  Thus, the potential difference generated at both ends of one common mode coil is equal to the potential difference generated at both ends of the other common mode coil. A potential difference (for example, 2 [V]) generated at both ends of one common mode coil is represented by common mode current × common mode impedance. Here, the common mode current includes a current flowing through the common mode coil LG2 from the first drive node GO toward the gate terminal of the second semiconductor switch element IGBT2, and a second current from the emitter terminal of the second semiconductor switch element IGBT2. This is the difference from the current flowing through the common mode coil LE2 toward the drive node EO. The common mode impedance is a value based on the mutual inductance of the common mode coil LG2 and the common mode coil LE2, and the self inductance of the common mode coil LG2 is equal to the self inductance of the common mode coil LE2. When the common mode current is zero, the common mode coil LG2 and the common mode coil LE2 cancel each other out of the magnetic flux, and the potential difference generated at both ends of one common mode coil becomes zero.

1.3. Gate Voltage FIG. 7 shows an equivalent configuration diagram of a driving device including a common mode filter. The operation when the driving apparatus 100 of FIG. 1 includes common mode filters such as the common mode coils LE2, LE3, LG2, and LG3 will be described. Due to the characteristics of the common mode filter as described above, in the example of FIG. 7, it is assumed that the potential difference generated at both ends of one common mode coil is, for example, 2 [V]. When the common mode impedance is 1000 [Ω], the current flowing through one common mode coil is 2 [mA]. Even if each resistance value (10 [Ω]) of the gate resistors RG2 and RG3 is smaller than the resistance value (18 [Ω]) of the gate resistor RG1 due to the presence of the common mode filter, the semiconductor switch elements IGBT2, 3 Are equal to the gate voltage of the first semiconductor switch element IGBT1. Accordingly, all the semiconductor switch elements IGBT1, IGBT2, and IGBT3 are turned on simultaneously. In the example of FIG. 7, the voltage between the first drive node GO and the second drive node EO is, for example, 15 [V] (the voltage of the first drive node GO = 15 [V], When the voltage of the drive node EO = 0 [V]) changes to 0 [V] (the voltage of the first drive node GO = 0 [V], the voltage of the second drive node EO = 0 [V]), All the semiconductor switch elements IGBT1, IGBT2, and IGBT3 are simultaneously turned off.

  In this way, by adjusting the resistance value between the semiconductor switch elements IGBT1, IGBT2, IGBT3 and the drive circuit DR, the drive circuit DR can drive all the semiconductor switch elements IGBT1, IGBT2, IGBT3 simultaneously. it can. At this time, as shown in FIG. 1, no resistor is provided between the first semiconductor element switch element IGBT1 and the drive circuit DR on the emitter terminal E side of the first semiconductor switch element IGBT1. . Therefore, when the current at the emitter sense terminal S representing the current at the emitter terminal E of the first semiconductor switch element IGBT1 is detected by the detection node SO, the detection accuracy can be improved.

2. Driving circuit 8 show an example of the construction of the drive circuit including a detection circuit. In the example of FIG. 8, the drive circuit DR includes a detection circuit as shown in FIG. 5 of Patent Document 3, for example, but the detection circuit may be provided outside the drive circuit DR. In the example of FIG. 8, the detection circuit includes a comparator CM, a sense resistor RS, and a reference voltage VR. The transistors T1 and T2 (drive unit) of the drive circuit DR operate with the power supply potential VDD (first power supply potential) and the ground potential GND (second power supply potential), and for example, a pulse signal having an amplitude of 15 [V]. Is output between the first drive node GO and the second drive node EO. The gate control circuit GC of the drive circuit DR inputs the input signal (pulse signal) from the input node IN, and operates the transistors T1 and T2 unless receiving the stop signal (cut-off signal) from the comparator CM.

  As shown in FIG. 1, since no resistor is provided between the emitter terminal E of the first semiconductor element switch element IGBT1 and the second drive node EO of the drive circuit DR, The potential is equal to the potential of the second drive node EO. In the example of FIG. 8, the potential of the second drive node EO (and hence the potential of the emitter terminal E) is equal to the ground potential GND, and the comparator CM is the first reference voltage VR with respect to the ground potential GND. The current at the emitter sense terminal S representing the current at the emitter terminal E of the semiconductor switch element IGBT1 is detected. In this case, the reference voltage VR becomes a value as designed when viewed from the emitter E side of the first semiconductor switch element IGBT1, and the comparator CM detects a stop signal (cut-off signal) when an overcurrent as designed is detected. Can be sent to the gate control circuit GC. Thus, the detection accuracy of overcurrent can be improved. In other words, when a resistor is provided between the emitter terminal E of the first semiconductor element switch element IGBT1 and the second drive node EO of the drive circuit DR, the comparator CM is caused by the resistance. A current different from the design may be erroneously detected as an overcurrent.

3. Modification FIG. 9 shows a modification of the drive device 100 of FIG. 9, the same reference numerals as those in FIG. 1 indicate the same configurations as those in FIG. 1, and the description of the same configurations is omitted. In the example of FIG. 9, the driving device 100 includes a set of three-wire common mode coils LG1, LS1, and LE1 corresponding to the first semiconductor element switch element IGBT1. Also in the example of FIG. 9, no resistor is provided between the first semiconductor element switch element IGBT1 and the drive circuit DR on the emitter terminal E side of the first semiconductor switch element IGBT1. The drive circuit DR can drive all the semiconductor switch elements IGBT1, IGBT2, and IGBT3 simultaneously.

  Note that the direct current flowing through the common mode coil LE1 can be generated by a potential difference generated between the emitters E, E, E of the semiconductor switch elements IGBT1, IGBT2, IGBT3. However, since at least one of the emitter resistor RE2 and the emitter resistor RE3 is inserted in the route of the current flowing into the common mode coil LE1, the magnetic saturation of the common mode coil LE1 can be suppressed.

  Note that the present invention is not limited to the above-described exemplary embodiments, and those skilled in the art can easily change the above-described exemplary embodiments to the scope included in the claims. I will.

  DESCRIPTION OF SYMBOLS 100 ... Drive device, C ... Collector terminal (3rd terminal), CM ... Comparator, DR ... Drive circuit, E ... Emitter terminal (2nd terminal), EO ... Second drive node, G: gate terminal (first terminal), GC: gate control circuit, GND: ground potential, GO: first drive node, IGBT1, IGBT2, IGBT3 ... Semiconductor switch element (IGBT), IN ... input node, LE2, LE3, LG2, LG3 ... common mode coil, N ... second output node, ND1, ND2, ND3 ... divided Node, P: First output node, RG1, RG2, RG3, RGC: Gate resistance, RS: Sense resistance, S: Emitter sense terminal (fourth terminal), SO: Detection node, T1, T2 ... Register, VR ··· reference voltage, VDD ··· power supply potential

Claims (2)

A first semiconductor switch element having a first terminal, a second terminal, a third terminal, and a fourth terminal;
A detection node for detecting a current at the fourth terminal representing a current at the second terminal of the first semiconductor switch element;
At least one semiconductor switch element connected in parallel with the first semiconductor element switch, each having a first terminal, a second terminal and a third terminal;
A drive circuit having a first drive node and a second drive node and driving the first semiconductor switch element and the at least one semiconductor switch element;
A first resistor on a first terminal side provided between the first drive node of the drive circuit and the first terminal of the first semiconductor switch element;
One resistance of at least one set of resistors and one of at least one set of common mode filters provided between the first drive node of the drive circuit and the first terminal of the at least one semiconductor switch element. A common mode filter,
The other resistance of the at least one set of resistors and the at least one set of common mode filters provided between the second drive node of the drive circuit and the second terminal of the at least one semiconductor switch element. The other common mode filter,
With
The resistance value of the first resistor is a resistance value of one of the at least one set of resistors corresponding to any one semiconductor switch element of the at least one semiconductor switch element and the resistance value of the first resistor. It is equal to the sum of the resistance value of the other resistor of any one set of resistors,
The second drive node of the drive circuit is directly connected to the second terminal of the first semiconductor switch element without any resistance, and connected in parallel. Drive device. The at least one semiconductor switch element includes a second semiconductor switch element and a third semiconductor switch element;
The at least one set of resistors includes a first set of resistors corresponding to the second semiconductor switch element and a second set of resistors corresponding to the third semiconductor switch element;
The at least one set of common mode filters includes a first set of common mode filters corresponding to the second semiconductor switch elements, and a second set of common mode filters corresponding to the third semiconductor switch elements. Have
The resistance value of the first resistor is a resistance value of one resistance of the first set of resistors corresponding to the second semiconductor switch element and a resistance value of the other resistance of the first set of resistors. Equal to the sum of
The resistance value of the first resistor is a resistance value of one resistance of the two sets of resistors corresponding to the third semiconductor switch element and a resistance value of the other resistance of the second set of resistors. 2. The driving device for semiconductor switch elements connected in parallel according to claim 1, wherein the driving device is equal to the added value.

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