JP2020022256A - Gate drive circuit and electric power conversion device - Google Patents

Abstract

To provide a gate drive circuit and an electric power conversion device capable of suppressing damage of a switching portion, even when inductance of a plurality of gate wirings connected to a plurality of switching portions connected to each other in parallel or in series cannot be the same.SOLUTION: A gate drive circuit 1 (an electric power conversion device 100) includes a first transmission portion 10a connected to a first switching portion 30a and a second transmission portion 10b connected to a second switching portion 30b. The gate drive circuit 1 is constituted such that a resonance frequency ω1 of the first transmission portion 10a and a resonance frequency ω2 of the second transmission portion 10b are substantially equal to each other, and an attenuation coefficient ξ1 of the first transmission portion 10a and an attenuation coefficient ξ2 of the second transmission portion 10b are substantially equal to each other.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a gate drive circuit and a power conversion device.

  2. Description of the Related Art Conventionally, a gate driving circuit including a gate wiring connected to a gate terminal of a switching unit and a power converter have been known (for example, see Patent Document 1).

  Patent Document 1 discloses a power conversion device including a signal line connected to a switching element. This power converter includes a bridge circuit, a drive circuit, and a signal line connecting the bridge circuit and the drive circuit. In each phase of the bridge circuit, two series circuits including two switching elements connected in series to each other at a power output terminal (connection point) are provided. The two series circuits are connected in parallel because the power output terminals are connected to each other. The drive circuit includes a switching element on the upper arm side of one of the two series circuits (hereinafter referred to as a “first element”) and a switching element on the upper arm side of the other series circuit ( Hereafter, the same drive signal is output to the “second element”. The signal line includes a signal line connecting the driver circuit and the first element (hereinafter, referred to as a “first signal line”) and a signal line connecting the driver circuit and the second element (hereinafter, referred to as a “first signal line”). "A second signal line"). The first signal line and the second signal line have the same wiring length and the same cross-sectional area of the wiring, or an inductor is arranged in the middle of either the first signal line or the second signal line. ing. Thus, in this power converter, since the first signal line and the second signal line have the same inductance, malfunction of the switching element and breakage of the switching element due to generation of voltage oscillation in the signal line are prevented. Is suppressed.

Japanese Patent No. 5559265

  In the power conversion device of Patent Document 1, the wiring length of the first signal line and the wiring length of the second signal line are the same in order to suppress malfunction of the switching element due to the occurrence of voltage oscillation in the signal line. And the cross-sectional area of the wiring of the first signal line and the cross-sectional area of the wiring of the second signal line are the same, or the cross-sectional area of either the first signal line or the second signal line is An inductor is arranged.

  Here, it is conceivable to configure the power conversion device as disclosed in Patent Document 1 in a smaller size. However, in this miniaturized power conversion device, the position where the first signal line and the second signal line are routed may be limited due to the reduced internal space of the power conversion device, and It is considered that it is sometimes difficult to arrange a relatively large inductor. In such a case, it is difficult to make the wiring length or the cross-sectional area of the first signal line and the second signal line the same, and the first signal line or the second signal line is not provided in the middle of the first or second signal line. It is considered that it may be difficult to arrange a relatively large inductor such that the inductance of the first signal line is the same as the inductance of the second signal line. That is, in the gate drive circuit, the inductance of the first signal line may not be equal to the inductance of the second signal line due to the structure of the power converter. In this case, due to the difference between the inductance of the first signal line and the inductance of the second signal line, the operation timing of the switching element to which the first signal line is connected is different from the operation timing of the second signal line. There is a disadvantage that the operation timing of the switching element is shifted. As a result, the current flowing in the switching element that is turned on first or the switching element that is turned off later is concentrated, and in the switching element where the current is concentrated, the power loss increases and the heat is increased, or the large current interruption occurs. It is considered that the generation of the surge voltage easily damages the switching element.

  Therefore, in the conventional power conversion device (gate drive circuit) as described above, the first signal line (gate wiring) connected to the plurality of switching elements (switching units) connected in parallel (or directly connected) to each other. When the inductance cannot be made equal to the inductance of the second signal line (gate wiring), there is a problem that the switching element is easily damaged.

  SUMMARY An advantage of some aspects of the invention is to provide a plurality of gate wirings connected to a plurality of switching units connected in parallel or in series with each other. It is an object of the present invention to provide a gate drive circuit and a power conversion device that can prevent the switching unit from being damaged even when the inductance cannot be made the same.

  In order to achieve the above object, the inventor of the present application sets an inside of a gate drive circuit (a drive signal transmission unit including a gate wiring) as an RLC series circuit including a resistance value R, an inductance L, and a capacitance (electric capacity) C. By grasping the driving of the gate drive signal as pulse voltage driving of the RLC series circuit, the following configuration was found. That is, the gate drive circuit according to the first aspect of the present invention turns on and off based on a gate drive signal input to the gate terminal, and is connected to the gate terminals of a plurality of switching units connected in parallel or in series with each other, A plurality of drive signal transmission units including a plurality of gate lines having different inductances, and a signal input unit for inputting an input pulse signal to each of the plurality of gate lines, the plurality of drive signal transmission units include a plurality of drive signal transmission units. By adjusting at least one of the resistance value, the capacitance, and the inductance of at least one of the drive signal transmission units, the resonance frequencies are substantially equal to each other, and the attenuation coefficients are substantially equal to each other. It is configured to be equal. In the specification of the present application, "the resonance frequencies are substantially equal to each other and the damping coefficients are substantially equal to each other" means that the resonance frequencies are equal to each other and that the damping coefficients are equal to each other. It is described as including values that are close to each other (for example, an error rate of 20% or less) and that damping coefficients are close to each other (for example, a value of 30% or less). . The “error rate” is the difference between one resonance frequency (attenuation coefficient) and another resonance frequency (attenuation coefficient), and the difference value between one resonance frequency (attenuation coefficient) and another resonance frequency (attenuation coefficient). Are described as meaning a value obtained by dividing by the sum value of.

  In the gate drive circuit according to the first aspect of the present invention, as described above, at least one of the resistance value R, the capacitance C, and the inductance L of at least one drive signal transmission unit of the plurality of drive signal transmission units. By adjusting one of them, the plurality of drive signal transmission units are configured such that the resonance frequencies ω are substantially equal to each other and the attenuation coefficients 略 are substantially equal to each other. Accordingly, the voltages vo (t) input to the gate terminals of the plurality of switching units, which are determined by the resonance frequency ω and the attenuation coefficient 略, substantially match each other, so that the operation timings of the plurality of switching units are made substantially the same. be able to. Therefore, it is possible to suppress the current from being concentrated on some of the switching units. As a result, in the switching section where the current is concentrated, it is possible to suppress an increase in heat generation, and it is possible to suppress generation of a surge voltage due to interruption of a large current, thereby suppressing damage to the switching section. can do. Therefore, even when the inductances of the plurality of gate lines connected to the plurality of switching units connected in parallel or in series cannot be the same, it is possible to prevent the switching units from being damaged. In the specification of the present application, “the operation timings are substantially the same” means not only that the change start time of the voltage value of the gate drive signal is the same, but also that the falling waveform or the falling waveform is substantially the same. It is described as meaning.

  In the gate drive circuit according to the first aspect, preferably, the plurality of gate wirings are configured such that the wiring lengths of the plurality of gate wirings are different from each other, so that the inductances of the plurality of gate wirings are different from each other, Since the capacitances of at least one of the plurality of drive signal transmission units are adjusted, the plurality of drive signal transmission units have substantially the same resonance frequency and substantially the same attenuation coefficient. It is configured as follows. With this configuration, the resonance frequency ω (= {1 / (√LC)｝) and the attenuation coefficient ξ (= R / 2 × √C / √L) include the component of the capacitance C. By adjusting the capacitance C, the gate drive circuit can be easily configured such that the resonance frequencies ω and the attenuation coefficients の of the plurality of drive signal transmission units are substantially equal. As a result, even when the wiring lengths of the plurality of gate lines are different from each other and the inductances L are different from each other, it is possible to easily suppress the switching section from being damaged.

  In this case, preferably, the plurality of drive signal transmission units have substantially the same resonance frequency because the resistance value and the capacitance of at least one of the plurality of drive signal transmission units are adjusted. At the same time, the damping coefficients are configured to be substantially equal to each other. With this configuration, after adjusting the resonance frequency ω by adjusting the capacitance C, the component of the resistance value R not included in the resonance frequency ω but included in the damping coefficient 、 is adjusted. The gate drive circuit can be configured more easily so that the resonance frequencies ω and the attenuation coefficients の of the transmission units are substantially equal.

  In the gate drive circuit in which the capacitance is adjusted, preferably, at least one of the plurality of drive signal transmission units has an input-side parasitic capacitor of the switching unit and a separate input-side parasitic capacitor. Are provided, and the plurality of drive signal transmission units have resonance frequencies substantially equal to each other because the combined capacitance of the input-side parasitic capacitor and the additional capacitor is adjusted. , The damping coefficients are substantially equal to each other. With this configuration, the drive signal transmission unit adjusts the capacitance of the additional capacitor as compared with a case where the semiconductor device itself included in the switching unit is reconfigured (designed) to adjust the capacitance of the input-side parasitic capacitor. By doing so, the capacitance (combined capacitance) of the drive signal transmission unit can be easily adjusted.

  In the gate drive circuit in which the capacitance is adjusted, preferably, at least one of the plurality of drive signal transmission units includes a plurality of semiconductors of a plurality of switching units provided with a plurality of semiconductor elements. The plurality of drive signal transmission units include an input-side parasitic capacitor of the element, and the combined resonance capacitance of the input-side parasitic capacitors of the plurality of semiconductor elements is adjusted so that the resonance frequencies become substantially equal to each other and the attenuation is reduced. The coefficients are configured to be substantially equal to each other. With this configuration, the capacitance (combined capacitance) of the drive signal transmission unit can be easily adjusted by adjusting the number of the plurality of semiconductor elements (semiconductor chips).

  In the gate drive circuit according to the first aspect, preferably, the plurality of drive signal transmission units have resonance frequencies of the plurality of drive signal transmission units substantially equal to each other, and the attenuation coefficients of the plurality of drive signal transmission units are substantially equal to each other. By being configured to be equal, a gate drive signal having substantially the same voltage rising waveform or substantially the same voltage falling waveform is transmitted to each of the plurality of switching units. With this configuration, a gate drive signal having substantially the same voltage rising waveform or substantially the same voltage falling waveform is transmitted to each of the plurality of switching units, so that the operation timing of the plurality of switching units can be easily adjusted. Can be aligned. As a result, breakage of the switching unit can be further suppressed.

  A power converter according to a second aspect of the present invention is configured to turn on / off based on a gate drive signal input to a gate terminal, and to be connected to a plurality of switching units connected in parallel or in series with each other, and to a gate terminal of the switching unit. A plurality of drive signal transmission units including a plurality of gate wirings having different inductances, and a signal input unit for inputting an input pulse signal to each of the plurality of gate wirings. By adjusting at least one of the resistance value, the capacitance, and the inductance of at least one of the plurality of drive signal transmission units, the resonance frequency becomes substantially equal to each other, and the attenuation coefficient is reduced. They are configured to be substantially equal to each other.

  In the power converter according to the second aspect of the present invention, with the configuration described above, similarly to the gate drive circuit according to the first aspect, the power converter is connected to a plurality of switching units connected in parallel or in series with each other. Even when the inductances of a plurality of gate wirings cannot be made the same, a power conversion device that can prevent the switching unit from being damaged can be provided.

  According to the present invention, as described above, even when the inductances of a plurality of gate wirings connected to a plurality of switching units connected in parallel or in series cannot be the same, the switching unit is damaged. Can be suppressed.

FIG. 1 is a block diagram illustrating an overall configuration of a power conversion device (gate drive circuit) according to a first embodiment of the present invention. FIG. 2 is a circuit diagram for explaining a configuration of a power conversion device (gate drive circuit) according to the first embodiment of the present invention. FIG. 3 is a circuit diagram illustrating a configuration of a first drive signal transmission unit, a second drive signal transmission unit, a first switching unit, and a second switching unit according to the first embodiment of the present invention. FIG. 3 is an equivalent circuit diagram of (a) a first drive signal transmission unit and (b) a second drive signal transmission unit according to the first embodiment of the present invention. FIG. 4 is a diagram for explaining an example of (a) before and (b) after the adjustment of the resistance value and the capacitance of the gate drive circuit according to the first embodiment of the present invention. FIG. 4 is a diagram for explaining a voltage rising waveform (turn-on waveform) and a voltage falling waveform (turn-off waveform) of a gate drive signal of the gate drive circuit according to the first embodiment of the present invention. FIG. 9 is a diagram for explaining a voltage rising waveform (turn-on waveform) and a voltage falling waveform (turn-off waveform) of a gate drive signal of a gate drive circuit according to a comparative example. FIG. 9 is a circuit diagram illustrating a configuration of a gate drive circuit according to a second embodiment of the present invention. It is an equivalent circuit diagram of (a) 1st drive signal transmission part and (b) 2nd drive signal transmission part by 2nd Embodiment of this invention. It is a figure for explaining the example of before (a) adjustment and after (b) adjustment of resistance value and capacitance of the gate drive circuit by a 2nd embodiment of the present invention. FIG. 6 is a diagram illustrating a configuration of a power conversion device according to a modification of the first and second embodiments of the present invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
(Configuration of power converter)
The configuration of the power conversion device 100 (gate drive circuit 1) according to the first embodiment will be described with reference to FIGS.

  As shown in FIG. 1, the power conversion device 100 includes a gate drive circuit 1 and a bridge circuit 2. In the first embodiment, the power conversion device 100 is configured as a power conversion device (power supply device) for, for example, an uninterruptible power supply device, a system interconnection, and a railway vehicle. The gate drive circuit 1 is configured to input a gate drive signal Gs (see FIG. 2) to each of the plurality of switching units 30 provided in the bridge circuit 2. Gate drive circuit 1 includes a plurality of drive signal transmission units 10 (hereinafter, “transmission unit 10”) and a gate drive unit 20 (hereinafter, “GDU20”). The GDU 20 is an example of the “signal input unit” in the claims.

  As shown in FIG. 2, the bridge circuit 2 is configured as, for example, three-phase (U-phase, V-phase, and W-phase) bridge circuits 2U, 2V, and 2W. Here, since the bridge circuits 2U, 2V, and 2W have the same configuration as each other, in the following description, the bridge circuit 2U will be described, and the description of the bridge circuits 2V and 2W will be omitted.

  The bridge circuit 2U is provided with an upper arm 2a and a lower arm 2b. The upper arm portion 2a is connected to the positive electrode terminal Tp and connected to the power output terminals To, and is provided with a plurality (for example, two) of switching portions 30 connected in parallel with each other. . The lower arm portion 2b is connected to the negative electrode terminal Tn and connected to the power output terminals To, and is provided with a plurality (for example, two) of switching portions 30 connected in parallel with each other. . The upper arm 2a and the lower arm 2b are connected to each other (connected in series) between the positive terminal Tp and the negative terminal Tn via the power output terminal To. In the following description, since the upper arm 2a and the lower arm 2b are configured similarly, only the upper arm 2a will be described, and the description of the lower arm 2b will be omitted.

  As shown in FIG. 3, in the first embodiment, the upper arm unit 2a includes two switching units 30 each configured as a semiconductor module. The switching unit 30 includes, for example, a semiconductor device 31 such as a field effect transistor (FET) or an insulated gate bipolar transistor (IGBT). Preferably, semiconductor device 31 is configured as a semiconductor element (SiC-MOSFET) containing silicon carbide (SiC). Here, one of the two switching units 30 is referred to as a first switching unit 30a, and the other is referred to as a second switching unit 30b.

  The gate terminal Ga of the first switching unit 30a is connected to the GDU 20 via a first drive signal transmission unit 10a (hereinafter, referred to as a "first transmission unit 10a"). The gate terminal Gb of the second switching unit 30b is connected to the GDU 20 via a second drive signal transmission unit 10b (hereinafter, referred to as a “second transmission unit 10b”). The first switching unit 30a includes a drain terminal Da connected to the positive terminal Tp, and a source terminal Sa connected to the power output side terminal To. The second switching unit 30b includes a drain terminal Db connected to the positive terminal Tp, and a source terminal Sb connected to the power output side terminal To. The first switching section 30a is configured to turn on and off based on a gate drive signal Gs input to the gate terminal Ga. The second switching unit 30b is configured to turn on and off based on a gate drive signal Gs input to the gate terminal Gb. Note that "on / off" is described as meaning an operation of switching between a state of conducting between the drain terminal Da (or Db) and the source terminal Sa (or Sb) and a state of disconnecting.

(Configuration of gate drive circuit)
As shown in FIG. 1, each transmission unit 10 of the gate drive circuit 1 has a function of transmitting a gate drive signal Gs from the GDU 20 to each switching unit 30. The GDU 20 is configured to input an input pulse signal vi (see FIG. 2) to each of the gate lines 11a and 11b of the plurality of transmission units 10.

  The plurality of transmission units 10 are provided in the gate drive circuit 1 in the same number as the plurality of switching units 30. As shown in FIG. 3, among the plurality of transmission units 10, the transmission unit 10 connected to the first switching unit 30a is a first transmission unit 10a, and the transmission unit 10 connected to the second switching unit 30b is a second transmission unit 10b. It is assumed that the transmitting portion 10b is used. The first transmission unit 10a includes a gate wiring 11a connected to the gate terminal Ga and having an inductance L1. The second transmission unit 10b includes a gate line 11b connected to the gate terminal Gb and having an inductance L2.

  In the first embodiment, the gate wiring 11a and the gate wiring 11b are different from each other in that the wiring length A1 of the gate wiring 11a and the wiring length A2 of the gate wiring 11b are different from each other. The configuration is such that the magnitude of the inductance L2 of the wiring 11b is different from the magnitude of the inductance L2. The first transmission unit 10a is provided with a signal line 11c that connects the source terminal Sa and the terminal 22 of the GDU 20. The second transmission unit 10b is provided with a signal line 11d that connects the source terminal Sb and the terminal 22 of the GDU 20.

  FIG. 4A shows an equivalent circuit of the first transmitting unit 10a, and FIG. 4B shows an equivalent circuit of the second transmitting unit 10b. Here, in the first embodiment, the first transmission unit 10a and the second transmission unit 10b are configured to include at least one of the resistance value R1 or R2 of the first transmission unit 10a and the second transmission unit 10b, the capacitance C1 or C2, In addition, since at least one of the inductances L1 and L2 is adjusted, the resonance frequencies ω1 and ω2 are substantially equal to each other, and the damping coefficients ξ1 and ξ2 are substantially equal to each other.

  Specifically, as shown in FIGS. 3 and 4A, the first transmission unit 10a includes a gate line 11a, a gate resistor 12a, and an input-side parasitic capacitor of the first switching unit 30a (semiconductor device 31). 31a. That is, the first transmission unit 10a can be represented as an equivalent circuit of an RLC series circuit including the resistance value R1, the inductance L1, and the capacitance C1. Here, the resistance value R1 is the resistance value of the entire first transmission unit 10a including the resistance value of the gate resistor 12a and the resistance value of the gate wiring 11a. The inductance L1 is the inductance of the entire first transmission unit 10a including the inductance of the gate wiring 11a. The capacitance C1 is the capacitance of the entire first transmission unit 10a including the capacitance C11 of the input-side parasitic capacitor 31a of the first switching unit 30a.

ここで、伝達関数Ｇ（ｓ）を２次振動系の伝達関数とし、伝達部１０の共振周波数をωとし、減衰係数（ダンピングファクタ）をξとすると、以下の式（２）および（３）が成立する。

これにより、ゲート駆動信号Ｇｓの立上り波形としての電圧ｖｏ（ｔ）は、オン時のゲート電圧をＶｇｓｏｎとし、オフ時のゲート電圧をＶｇｓｏｆｆとした場合、以下の式（４）および（５）として表すことができる。

したがって、上記式（３）のＲにＲ１、ＣにＣ１、および、ＬにＬ１を代入すると、共振周波数ω１および減衰係数ξ１は、以下の式（６）となる。

Here, the voltage waveform vo (t) of the gate drive signal Gs in the transmission unit 10 satisfies the following equation (1) in an RLC series circuit including a resistance value R, an inductance L, and a capacitance C. The voltage of the input pulse signal vi is represented by vi (t) (after Laplace transform Vi (s)), the voltage between the gate terminal and the source terminal of the switching unit 30 is represented by vo (t) (after Laplace transform Vo (s)) and Let the transfer function be G (s).

Here, assuming that the transfer function G (s) is the transfer function of the secondary vibration system, the resonance frequency of the transfer unit 10 is ω, and the damping coefficient (damping factor) is ξ, the following equations (2) and (3) Holds.

Accordingly, the voltage vo (t) as the rising waveform of the gate drive signal Gs is represented by the following equations (4) and (5) when the gate voltage at the time of on is Vgson and the gate voltage at the time of off is Vgsoff. Can be represented.

Therefore, if R1 is substituted for R, C1 is substituted for C, and L1 is substituted for L in the above equation (3), the resonance frequency ω1 and the damping coefficient ξ1 become the following equation (6).

Here, as shown in FIG. 3, in the first embodiment, the second transmission unit 10b includes a gate wiring 11b, a gate resistor 12b, and an input-side parasitic capacitor 31a of the second switching unit 30b (semiconductor device 31). , And an additional capacitor 13 configured separately from the input-side parasitic capacitor 31a. For example, the additional capacitor 13 is connected in parallel to the input-side parasitic capacitor 31a. Here, as shown in FIG. 4B, the second transmission unit 10b is expressed as an equivalent circuit of an RLC series circuit of the resistance value R2, the inductance L2, and the capacitance C2, similarly to the first transmission unit 10a. Can be. That is, when R2 is substituted for R in the above equation (3), C2 is substituted for C, and L2 is substituted for L, the resonance frequency ω2 and the damping coefficient な る 2 become the following equation (7).

Here, in the first embodiment, the gate drive circuit 1 adjusts the capacitance C2 of the second transmission unit 10b (preferably, both the resistance value R2 and the capacitance C2 of the second transmission unit 10b are adjusted). ), The resonance frequencies ω1 and ω2 are substantially equal to each other, and the damping coefficients ξ1 and ξ2 are substantially equal to each other. “The resonance frequencies ω1 and ω2 are substantially equal to each other” means, for example, that the resonance frequencies ω1 and ω2 are within the range shown by the following equation (8), and “the attenuation coefficients ξ1 and ξ2 and "Approximately equal to each other" means that, for example, the attenuation coefficients ξ1 and 範 囲 2 are within the range indicated by the following equation (9). That is, if the resonance frequencies ω1 and ω2 are within the range shown by the following equation (8) and the attenuation coefficients ξ1 and ξ2 are within the range shown by the following equation (9), the first switching unit 30a Concentration of current on one of the second switching units 30b is suppressed.

  Specifically, as shown in FIG. 4, in the gate drive circuit 1, the capacitance C2 is adjusted (set) based on the difference between the inductance L1 and the inductance L2 so that the resonance frequencies ω1 and ω2 become substantially equal. Have been. In the first embodiment, the capacitance C2 is a capacitance (C21 + C22) obtained by combining the capacitance C21 of the input-side parasitic capacitor 31a and the capacitance C22 of the additional capacitor 13. Further, in the gate drive circuit 1 of the first embodiment, the input-side parasitic capacitor 31a and the additional capacitor 13 combine so that the resonance frequencies ω1 and ω2 are substantially equal to each other and the attenuation coefficients ξ1 and ξ2 are substantially equal to each other. The adjusted capacitance C2 is adjusted. In order to adjust the capacitance C22 (combined capacitance C2), the additional capacitor 13 may be configured by a capacitor having a fixed capacitance, or may be configured as a variable capacitance capacitor.

  In the gate drive circuit 1, the value of the resistance value R2 is adjusted (set) so that the attenuation coefficients ξ1 and ξ2 are substantially equal. For example, in the gate drive circuit 1, the resistance value R1 (for example, the resistance value of the gate resistance 12a) and the resistance value R2 (for example, the resistance value of the gate resistance 12b) are set to different values. The gate resistances 12a and 12b are not limited to being configured as resistors having a fixed resistance value, and the resistance values of the gate resistance 12a and the gate resistance 12b can be set to different values. It may be constituted by a variable resistor, or the number of resistors may be changed.

  GDU 20 includes, for example, an oscillator, a CPU (Central Processing Unit), and the like. Then, as shown in FIG. 2, the first transmission unit 10a and the second transmission unit 10b are connected to the pulse output unit 21 of the GDU 20. Then, as shown in FIG. 4, the GDU 20 is configured to input the same input pulse signal vi (rectangular signal) from the pulse output unit 21 to each of the first transmission unit 10a and the second transmission unit 10b. .

  Thereby, as shown in FIG. 6, the first transmission unit 10a and the second transmission unit 10b are configured such that the resonance frequencies ω1 and ω2 are substantially equal to each other, and the attenuation coefficients ξ1 and ξ2 are substantially equal to each other. Accordingly, each of the first switching unit 30a and the second switching unit 30b has a gate drive having substantially the same voltage rising waveform (turn-on waveform) and substantially the same voltage falling waveform (turn-off waveform). It is configured to transmit the signal Gs. That is, the gate drive circuit 1 is configured such that the operation timing of the first switching unit 30a and the operation timing of the second switching unit 30b substantially match.

(Comparison result between the gate drive circuit according to the first embodiment and the gate drive circuit according to the comparative example)
Next, with reference to FIGS. 5 to 7, a comparison result between the gate drive circuit 1 according to the first embodiment (an example after adjustment) and the gate drive circuit according to a comparative example (an example before adjustment) will be specifically described. A description will be given using numerical examples. Note that the configuration of the gate drive circuit according to the comparative example does not mean the related art, but is a configuration indicating a state before the resistance value R2 and the capacitance C2 of the gate drive circuit 1 according to the first embodiment are adjusted. .

  As shown in FIG. 5A, in the first drive signal transmission unit of the gate drive circuit (gate drive circuit before adjustment) according to the comparative example, the resistance value R1c is 5Ω, the inductance L1c is 0.5 μH, and the capacitance C1c is 15 nF. , The resonance frequency ω1c is 11.5 MHz, and the attenuation coefficient ξ1c is 0.43. Further, in the second drive signal transmitting section of the gate drive circuit (gate drive circuit before adjustment) according to the comparative example, the resistance value R2c is 5Ω, the inductance L2c is 0.25 μH, the capacitance C2c is 15 nF, and the resonance frequency ω2c is 16.3 MHz. , And the attenuation coefficient ξ2c is 0.61. That is, in the gate drive circuit according to the comparative example, the first drive signal transmission unit and the second drive signal transmission unit are different in the magnitude of the inductance, the resonance frequency, and the attenuation coefficient.

  As shown in FIG. 5B, in the first transmission unit 10a of the gate drive circuit 1 according to the first embodiment, the resistance value R1 is 5Ω, the inductance L1 is 0.5 μH, the capacitance C1 is 15 nF, and the resonance frequency ω1 is 11 It is assumed that 0.5 MHz and the attenuation coefficient ξ1 are 0.43. Here, in the second transmission unit 10b, the resistance value R2 is adjusted (decreased) by Ra (2.5Ω) from R2c, which is 5Ω, to 2.5Ω, the inductance L2 is 0.25 μH, and the capacitance is C2 is adjusted to 30 nF from C21 (C2c), which is 15 nF, and adjusted (increased) by C22 (the capacitance C22 of the additional capacitor 13), the resonance frequency ω2 is 11.5 MHz, and the attenuation coefficient ξ2 is 0 .43. That is, in the gate drive circuit 1 according to the first embodiment, ω1 = ω2, and ξ1 = ξ2.

  FIG. 6 shows waveforms (turn-on waveform and turn-off waveform) showing the gate voltage vo (t) at the gate terminals Ga and G2 in the gate drive circuit 1 according to the first embodiment, and FIG. 7 shows the gate drive according to the comparative example. 7 shows waveforms (turn-on waveform and turn-off waveform) indicating a gate voltage vo (t) at a gate terminal in the circuit.

  In the gate drive circuit according to the comparative example, the gate voltage vo (t) (solid line) via the first drive signal transmission unit matches the gate voltage vo (t) (dotted line) via the second drive signal transmission unit. However, it has been found that the operation timing of the first switching unit connected to the first drive signal transmission unit is different from the operation timing of the second switching unit connected to the second drive signal transmission unit. For example, in the example illustrated in FIG. 7, the operation timing of the first switching unit and the operation timing of the second switching unit are shifted for a period of Δt before reaching the predetermined voltage value Vt.

  In the gate drive circuit 1 according to the first embodiment, the gate voltage vo (t) via the first transmission unit 10a matches the gate voltage vo (t) via the second transmission unit 10b, and the first transmission It has been found that the operation timing of the first switching unit 30a connected to the unit 10a and the operation timing of the second switching unit 30b connected to the second transmission unit 10b match. In FIG. 6, each of the waveform at the time of turn-on and the waveform at the time of turn-off is shown by one solid line, but the waveform of the gate voltage vo (t) via the first transmission unit 10a and the second transmission unit 10b are not shown. This shows that the waveform of the gate voltage vo (t) passes through the waveform.

[Effects of First Embodiment]
In the first embodiment, the following effects can be obtained.

  In the first embodiment, as described above, since at least one of the resistance value R, the capacitance C, and the inductance L of the second transmission unit 10b is adjusted, the resonance frequencies ω become substantially equal to each other. , The first transmission unit 10a and the second transmission unit 10b are configured such that the attenuation coefficient 略 becomes substantially equal to each other. Thereby, the voltages vo (t) input to the gate terminal Ga of the first switching unit 30a and the gate terminal Gb of the second switching unit 30b are determined by the resonance frequencies ω1 and ω2 and the attenuation coefficients ξ1 and ξ2 (see FIG. 7), the operation timings of the first switching unit 30a and the second switching unit 30b can be made substantially the same. Therefore, it is possible to suppress the current from being concentrated on one of the first switching unit 30a and the second switching unit 30b. As a result, in the switching unit 30 where the current is concentrated, it is possible to suppress an increase in heat generation and to suppress generation of a surge voltage due to interruption of a large current, so that the switching unit 30 is not damaged. Can be suppressed. Therefore, even when the inductances L1 and L12 of the plurality of gate lines 11a and 11b connected to the first switching unit 30a and the second switching unit 30b connected in parallel or in series cannot be the same, The switching section 30 can be prevented from being damaged.

  In the first embodiment, as described above, the gate wirings 11a and 11b are configured such that the wiring lengths A1 and A2 are different from each other, so that the inductances L1 and L2 are different from each other. By adjusting the capacitance C2 of the second transmission unit 10b, the gate drive circuit 1 is configured so that the resonance frequencies ω1 and ω2 are substantially equal to each other and the attenuation coefficients ξ1 and ξ2 are substantially equal to each other. As a result, as in the above equations (6) and (7), the resonance frequency ω2 and the attenuation coefficient ξ2 include the component of the capacitance C2. The gate drive circuit 1 can be easily configured such that the resonance frequencies ω1 and ω2 of the 10a and the second transmission unit 10b and the attenuation coefficients ξ1 and ξ2 are substantially equal. As a result, even when the wiring length A1 of the gate wiring 11a and the wiring length A2 of the gate wiring 11b are different from each other and the inductances L1 and L2 are different from each other, it is possible to easily suppress the switching unit 30 from being damaged. it can.

  In the first embodiment, as described above, by adjusting the resistance value R2 and the capacitance C2 of the second transmission unit 10b, the resonance frequencies ω1 and ω2 are made substantially equal to each other, and the attenuation coefficients ξ1 and ξ2 Are configured to make the gate drive circuit 1 substantially equal to each other. Thus, after adjusting the resonance frequencies ω1 and ω2 by adjusting the capacitance C2 as in the above equations (6) and (7), the resistance value R2 not included in the resonance frequency ω2 but included in the attenuation coefficient ξ2 is obtained. , The gate drive circuit 1 is further easily configured such that the resonance frequencies ω1 and ω2 of the first transmission unit 10a and the second transmission unit 10b and the attenuation coefficients ξ1 and ξ2 become substantially equal. can do.

  In the first embodiment, as described above, the second transmission unit 10b includes the input-side parasitic capacitor 31a of the second switching unit 30b, and the additional capacitor 13 that is configured separately from the input-side parasitic capacitor 31a. Is provided. In the second transmission unit 10b, the resonance frequencies ω1 and ω2 and the attenuation coefficients ξ1 and ξ2 become substantially equal because the capacitance C2 combined by the input-side parasitic capacitor 31a and the additional capacitor 13 is adjusted. And so on. Thereby, the first transmission unit 10a or the second transmission unit 10b is compared with a case where the semiconductor device 31 itself included in the switching unit 30 is reconfigured (designed) in order to adjust the capacitance C2 of the input-side parasitic capacitor 31a. By adjusting the capacitance C22 of the additional capacitor 13, the capacitance C2 (combined capacitance) of the transmission unit 10 can be easily adjusted.

  In the first embodiment, as described above, the first transmission unit 10a and the second transmission unit 10b are configured so that the resonance frequencies ω1 and ω2 and the attenuation coefficients ξ1 and ξ2 are substantially equal. Each of the first switching unit 30a and the second switching unit 30b is configured to transmit a gate drive signal Gs having substantially the same voltage rising waveform or substantially the same voltage falling waveform. According to this structure, the gate drive signal Gs having substantially the same voltage rising waveform or substantially the same voltage falling waveform is transmitted to each of the first switching unit 30a and the second switching unit 30b. The operation timings of the switching unit 30 can be easily aligned. As a result, breakage of the switching unit 30 can be further suppressed.

[Second embodiment]
Next, a configuration of the power conversion device 200 according to the second embodiment will be described with reference to FIGS. 1, 8, and 9. In the power conversion device 200 according to the second embodiment, the number of the semiconductor elements 231 (the number of semiconductor chips) is different from the first embodiment in which the capacitance C2 is adjusted by providing the additional capacitor 13 in the second transmission unit 10b. Is adjusted, the capacitances C102a and C102b are adjusted. In addition, about the same structure as the said 1st Embodiment, the same code | symbol is attached | subjected in the figure and shown, and the description is abbreviate | omitted.

  As shown in FIG. 1, in the second embodiment, the power conversion device 200 includes a gate drive circuit 201 and a bridge circuit 202. The gate drive circuit 201 includes a first drive signal transmission unit 210a (hereinafter, referred to as a “first transmission unit 210a”) and a second drive signal transmission unit 210b (hereinafter, referred to as a “second transmission unit 210b”). including. As shown in FIG. 8, the bridge circuit 202 is configured as one semiconductor module including a first switching unit 230a and a second switching unit 230b. The first switching unit 230a and the second switching unit 230b are each configured as a semiconductor chip group provided with a plurality of semiconductor elements 231 (semiconductor chips). Each of the semiconductor elements 231 is configured by a switching element (for example, a MOSFET or the like).

  The plurality of semiconductor elements 231 configuring the first switching unit 230a are connected to the gate line 211a of the first transmission unit 210a. The plurality of semiconductor elements 231 configuring the second switching unit 230b are connected to the gate wiring 211b of the second transmission unit 210b. That is, the gate drive signal Gs is input to the plurality of semiconductor elements 231 included in the first switching unit 230a at substantially the same operation timing. The gate drive signal Gs is input to the plurality of semiconductor elements 231 configuring the second switching unit 230b at substantially the same operation timing.

  Here, in the second embodiment, the first transmission unit 210a includes the input-side parasitic capacitors 231a of the N1 semiconductor elements 231 of the first switching unit 230a in which the plurality of semiconductor elements 231 are provided. The unit 210b includes the input-side parasitic capacitors 231a of the N2 semiconductor devices 231 of the second switching unit 230b provided with the plurality of semiconductor devices 231. The first transmission unit 210a and the second transmission unit 210b have the resonance frequencies ω11 and ω12 substantially equal to each other because the combined capacitances C102a and C102b of the input-side parasitic capacitors 231a of the plurality of semiconductor elements 231 are adjusted. The damping coefficients な る 1 and ξ2 are configured to be substantially equal to each other.

  Specifically, the number N1 of the semiconductor elements 231 included in the first switching unit 230a is different from the number N2 of the semiconductor elements 231 included in the second switching unit 230b. The capacitance of the input-side parasitic capacitor 231a of the semiconductor element 231 is C102. Thereby, as shown in FIG. 9, the combined capacitance C102a of the input-side parasitic capacitors 231a of the N1 semiconductor elements 231 of the first transmission unit 210a is equal to the combined capacitance C102a of the N2 semiconductor elements 231 of the second transmission unit 210b. The input-side parasitic capacitor 231a has a different value from the combined capacitance C102b.

  Here, in the second embodiment, by adjusting at least one of the number N1 and the number N2 (for example, both the number N1 and the number N2), the capacitance C102a of the first transmission unit 210a and the second transmission unit At least one of capacitance 210b (e.g., both capacitances C102a and C102b) is adjusted.

  Further, as shown in FIG. 9, the first transmission unit 210a is an RLC series circuit including a resistance value R11, an inductance L11, and a capacitance C102a. The second transmission unit 210b is an RLC series circuit including a resistance value R12, an inductance L12, and a capacitance C102b.

  The gate drive circuit 201 adjusts at least one of the resistance values R11 and R12 and at least one of the capacitances C102a and C102b to adjust the resonance frequency ω11 of the first transmission unit 210a and the second transmission unit 210b. The resonance frequency ω12 is substantially equal to each other, and the attenuation coefficient 、 11 of the first transmission unit 210a and the attenuation coefficient ξ12 of the second transmission unit 210b are approximately equal to each other. Other configurations of the second embodiment are the same as the configurations of the first embodiment.

(Example of Adjusting Resistance Value and Capacitance of Gate Drive Circuit According to Second Embodiment)
Next, an example of adjustment of the resistance value R11 and the capacitances C102a and C102b of the gate drive circuit 201 according to the second embodiment will be described with reference to FIG.

  FIG. 10A shows a numerical example of the resistance value and the like of the gate drive circuit 201 before the adjustment, and FIG. 10B shows the resistance value and the like of the gate drive circuit 201 after the adjustment (the second embodiment). Are shown as numerical examples. For example, the resistance value R11c of the first transmission unit 210a before adjustment and the resistance value R12c of the second transmission unit 210b before adjustment are 3Ω. Further, the inductance L11c of the first transmission unit 210a before the adjustment is set to 0.04 μH, and the inductance L12c of the second transmission unit 210b before the adjustment is set to 0.02 μH. The capacitance C11c of the first transmission unit 210a before the adjustment and the capacitance C12c of the second transmission unit 210b before the adjustment are 9 nF. In this case, the resonance frequency ω11c of the first transmission unit 210a before the adjustment is 52.7 MHz, and the resonance frequency ω12c of the second transmission unit 210b before the adjustment is 74.5 MHz (different from each other). Further, the attenuation coefficient ξ11c of the first transmission unit 210a before the adjustment is 0.71, and the attenuation coefficient ξ12c of the second transmission unit 210b before the adjustment is 1.01 (a value different from each other).

  Then, for example, by adjusting the resistance value from R11c to R11, from the capacitance C11c to C102a, and from the capacitance C12c to C102b, respectively, the resonance frequency ω11 of the first transmission unit 210a and the resonance frequency ω12 of the second transmission unit 210b are adjusted. Are substantially equal to each other, and the attenuation coefficient # 11 of the first transmission unit 210a and the attenuation coefficient # 12 of the second transmission unit 210b are approximately equal to each other.

  Specifically, the adjusted resistance value R11 of the first transmission unit 210a is 6Ω. The adjusted resistance value R12 of the second transmission unit 210b is 3Ω. The adjusted inductance L11 of the first transmission unit 210a is 0.04 μH, and the adjusted inductance L12 of the second transmission unit 210b is 0.02 μH. The capacitance C102a of the adjusted first drive signal transmission unit 210a is 6 nF by setting the number of the semiconductor elements 231 to N1. The capacitance C102b of the adjusted second transmission unit 210b becomes 12 nF by setting the number of the semiconductor elements 231 to N2. Accordingly, the adjusted resonance frequency ω11 of the first transmission unit 210a and the adjusted resonance frequency ω12 of the second transmission unit 210b are both 64.5 MHz, and the adjusted attenuation coefficient ξ11 of the first transmission unit 210a and the adjustment The attenuation coefficient # 12 of the subsequent second transmission unit 210b is 1.16.

[Effect of Second Embodiment]
In the second embodiment, the following effects can be obtained.

  In the second embodiment, as described above, the first transmission unit 210a includes the input-side parasitic capacitors 231a of the N1 semiconductor elements 231 in the first switching unit 230a. The second transmission unit 210b includes the input-side parasitic capacitors 231a of the N2 semiconductor elements 231 in the second switching unit 230b. The first transmission unit 210a and the second transmission unit 210b are configured such that the combined capacitances C102a and C102b of the input-side parasitic capacitors 231a of the plurality of semiconductor elements 231 are adjusted, so that the resonance frequencies ω11 and ω12 are substantially equal to each other. The damping coefficients # 11 and # 12 are configured to be substantially equal to each other. Thereby, the capacitances C102a and C102b can be easily adjusted by adjusting the number N11 and the number N12 of the plurality of semiconductor elements 231 (semiconductor chips). The other effects of the second embodiment are the same as the effects of the first embodiment.

[Modification]
It should be understood that the embodiments disclosed this time are illustrative in all aspects and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description of the embodiments, and includes all equivalents (modifications) within the scope and meaning equivalent to the claims.

  For example, in the above-described first and second embodiments, an example is shown in which the first switching unit and the second switching unit whose operation timings are aligned are connected in parallel with each other, but the present invention is not limited to this. That is, as in the power conversion device 300 of the modified example shown in FIG. 11, the first switching unit 330a connected to the gate wiring 11a of the first transmission unit 10a and the gate wiring 11b of the second transmission unit 10b are connected. The second switching unit 330b may be connected in series between the positive terminal Tp and the power output side terminal To. Such a power converter 300 can be applied, for example, to a power converter connected to a high-voltage power system such as for a power generation facility and a substation facility. Therefore, for example, even when the number of the plurality of switching units (first switching unit 330a and second switching unit 330b) connected in series is increased, the operation timings of the switching units can be easily made uniform.

  In the first and second embodiments, the resonance frequency of the first drive signal transmission unit and the resonance frequency of the second drive signal transmission unit are adjusted by adjusting the resistance value, the capacitance, and the resistance value and the capacitance of the inductance. Although an example has been shown in which the resonance frequency is made substantially equal and the attenuation coefficient of the first drive signal transmission unit is made substantially equal to the attenuation coefficient of the second drive signal transmission unit, the present invention is not limited to this. That is, by adjusting at least one of the resistance value, the capacitance, and the inductance (for example, only the capacitance, only the inductance, and all of the resistance value, the capacitance, and the inductance), the resonance frequency of the first drive signal transmission unit is adjusted. And the resonance frequency of the second drive signal transmission unit may be substantially equal, and the attenuation coefficient of the first drive signal transmission unit and the attenuation coefficient of the second drive signal transmission unit may be approximately equal.

  Further, in the first and second embodiments, an example is shown in which the wiring lengths of the plurality of gate wirings are different from each other, so that the inductances of the plurality of gate wirings are different from each other. Not limited. That is, the present invention may be applied to a case where the cross-sectional areas of a plurality of gate lines are different from each other, and the inductances of the plurality of gate lines are different from each other.

  Further, in the first embodiment, as shown in FIG. 4, an example is shown in which the additional capacitor is provided in the second drive signal transmission unit so as to be connected in parallel with the input-side parasitic capacitor, but the present invention is not limited to this. Absent. That is, the additional drive capacitor may be provided in the first drive signal transmission unit or the second drive signal transmission unit so as to be connected in series to the input-side parasitic capacitor.

  In the second embodiment, an example in which both the number (N1) of the input-side parasitic capacitors of the first drive signal transmission unit and the number (N2) of the input-side parasitic capacitors of the second drive signal transmission unit are adjusted. However, the present invention is not limited to this. That is, only one of N1 and N2 may be adjusted.

  Further, in the above-described embodiment, an example has been described in which the switching unit (semiconductor device) is configured by a SiC-MOSFET or an IGBT, but the present invention is not limited to this. That is, a semiconductor element (for example, a Si-MOSFET) other than the SiC-MOSFET and the IGBT may be used.

1, 201 Gate drive circuit 10 Drive signal transmission unit 10a, 210a First drive signal transmission unit 10b, 210b Second drive signal transmission unit 11a, 11b, 211a, 211b Gate wiring 13 Additional capacitor 20 GDU (signal input unit)
Reference Signs List 30 switching unit 31a, 231a input side parasitic capacitor 30a, 230a first switching unit 30b, 230b second switching unit 100, 200, 300 power conversion device 231 semiconductor element Ga, Gb gate terminal

Claims (7)

A plurality of driving units that turn on / off based on a gate driving signal input to a gate terminal and are connected to the gate terminals of a plurality of switching units connected in parallel or in series with each other and include a plurality of gate wirings having different inductances. A signal transmission unit,
A signal input unit for inputting an input pulse signal to each of the plurality of gate lines,
The plurality of drive signal transmitting units may be configured such that at least one of the resistance value, the capacitance, and the inductance of at least one of the plurality of drive signal transmitting units is adjusted, so that resonance occurs. A gate drive circuit configured to have substantially equal frequencies and substantially equal attenuation coefficients. The plurality of gate wirings are configured such that the wiring lengths of the plurality of gate wirings are different from each other, so that the inductances of the plurality of gate wirings are different from each other,
The plurality of drive signal transmission units are configured such that the capacitance of at least one of the plurality of drive signal transmission units is adjusted, so that the resonance frequencies are substantially equal to each other and the attenuation is reduced. 2. The gate drive circuit according to claim 1, wherein coefficients are configured to be substantially equal to each other.   The plurality of drive signal transmission units have the resonance frequencies substantially equal to each other by adjusting the resistance value and the capacitance of at least one of the plurality of drive signal transmission units. 3. The gate drive circuit according to claim 2, wherein the attenuation coefficients are configured to be substantially equal to each other. At least one of the plurality of drive signal transmission units is provided with an input-side parasitic capacitor of the switching unit and an additional capacitor configured separately from the input-side parasitic capacitor. Yes,
The plurality of drive signal transmission units are configured such that the capacitance combined by the input-side parasitic capacitor and the additional capacitor is adjusted, so that the resonance frequencies are substantially equal to each other and the attenuation coefficients are substantially equal to each other. The gate drive circuit according to claim 2, wherein the gate drive circuit is configured to: At least one of the plurality of drive signal transmission units includes the input-side parasitic capacitor of the plurality of semiconductor elements of the plurality of switching units provided with a plurality of semiconductor elements,
The plurality of drive signal transmission units are configured such that the combined capacitance of the input-side parasitic capacitors of the plurality of semiconductor elements is adjusted, so that the resonance frequencies are substantially equal to each other, and the attenuation coefficients are equal to each other. 4. The gate drive circuit according to claim 2, wherein the gate drive circuit is configured to be substantially equal.   The plurality of drive signal transmission units are configured such that the resonance frequencies of the plurality of drive signal transmission units are substantially equal to each other, and the attenuation coefficients of the plurality of drive signal transmission units are substantially equal to each other. The configuration according to any one of claims 1 to 5, wherein the gate drive signal having substantially the same voltage rising waveform or substantially the same voltage falling waveform is transmitted to each of the plurality of switching units. The gate drive circuit according to the paragraph. On and off based on a gate drive signal input to the gate terminal, a plurality of switching units connected in parallel or in series with each other,
A plurality of drive signal transmission units connected to the gate terminal of the switching unit and including a plurality of gate lines having different inductances;
A signal input unit for inputting an input pulse signal to each of the plurality of gate lines,
The plurality of drive signal transmitting units may be configured such that at least one of the resistance value, the capacitance, and the inductance of at least one of the plurality of drive signal transmitting units is adjusted, so that resonance occurs. A power converter configured to have substantially equal frequencies and substantially equal attenuation coefficients.

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