JP2010088175A - Inverter device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain an inverter device which can prevent the withstand-voltage breakage and the erroneous operation of a high withstand-voltage IC without being applied with a negative surge exceeding a design reference to the high withstand-voltage IC which drive-controls switching elements. <P>SOLUTION: The inverter device includes the voltage-type inverter 2 constituted of the switching elements T1 to T6, and an inverter drive circuit 3 which includes the high withstand-voltage IC 4 whose reference potential of an input signal is different from that of an output signal, and drives the switching elements T1 to T6. The inverter drive circuit 3 includes clamp diodes D7 to D9 whose cathodes are connected to high-voltage side terminals of the high withstand-voltage IC 4, and includes a clamp circuit which clamps the potential of an anode-side connecting point of the clamp diodes D7 to D9 to the potential of the high-voltage side reference terminals, a charging circuit composed of capacitive elements C1 to C3 which are connected to the clamp diodes D7 to D9 in parallel therewith, and an impedance element Z1 which voltage-divides the anode-side connecting point of the clamp diodes D7 to D9 and a negative pole of a DC power supply. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an inverter device, and more particularly to an inverter device provided with a circuit that prevents breakdown and malfunction of a high voltage IC that drives and controls a switching element.

  As a conventional inverter device, as a countermeasure against a negative potential surge (hereinafter referred to as a negative surge) caused by a current change amount (current change di / dt) generated when switching of a switching element, a low voltage side reference of a high voltage IC A clamping circuit connected between both reference terminals for clamping the terminal potential to the high-voltage reference terminal; and a voltage dividing circuit that divides the voltage between the low-voltage reference terminal and the DC power supply negative electrode. This prevents breakdown and malfunction of the high voltage IC (see, for example, Patent Document 1).

WO01 / 059918 (pages 7-10, FIG. 2)

  In the conventional inverter device, the resistance of the voltage dividing circuit section is obtained by dividing the gate resistance in terms of electric circuit. Therefore, the sum of the resistance value of the voltage dividing circuit section and the resistance value of the gate resistance connected to the switching element is: There is a restriction that it must be equal to the resistance value of the gate resistance when the voltage dividing circuit section is not provided. For this reason, in addition to the switching operation of the switching element, when an extremely large current change di / dt occurs due to external noise or the like, sufficient voltage division cannot be performed due to the limitation of the resistance value as described above. Further, in the clamp circuit portion, the clamp diode does not turn on immediately due to the transient characteristics, and as a result, there is a problem that the negative surge cannot be suppressed within the design standard of the high voltage IC.

  The present invention has been made to solve the above-mentioned problems, and a negative surge exceeding the design standard is not applied to a high voltage IC that drives and controls the switching element, thereby preventing breakdown and malfunction of the high voltage IC. An inverter device is obtained.

  An inverter device according to the present invention includes an inverter circuit connected between positive and negative electrodes of a DC power source and configured by at least a pair of switching elements, and a drive circuit in which a reference potential of an input signal and a reference potential of an output signal are different. And an inverter drive circuit that drives the switching element, and the inverter drive circuit is configured by a diode having a cathode connected to a high-voltage side reference terminal to which a potential serving as a reference of a signal on the high potential side of the drive circuit is applied. A clamping circuit section that clamps the potential at the anode-side connection point of the diode to the potential of the high-voltage side reference terminal, a charging circuit section that includes a capacitive element connected in parallel to the diode, and the anode-side connection point of the diode and the DC power supply Each switching that constitutes a pair of switching elements between the negative electrode and the cathode side connection point of the diode It is characterized in that it has a voltage dividing circuit part for dividing the at least one of between the connection point of the child.

  In addition, an inverter device according to the present invention includes an inverter circuit connected between positive and negative electrodes of a DC power supply and configured by at least one pair of switching elements, and a drive circuit in which a reference potential of an input signal and a reference potential of an output signal are different And an inverter drive circuit for driving the switching element, the inverter drive circuit having a cathode connected to a high-voltage side reference terminal to which a potential serving as a reference of a signal on the high potential side of the drive circuit is applied, and a plurality of It is composed of a parallel body of diodes, and clamp circuits that clamp the potential of the anode side connection points of the plurality of diodes to the potential of the high voltage side reference terminal, and between the anode side connection points of the plurality of diodes and the negative electrode of the DC power supply, Between the cathode side connection points of the plurality of diodes and the connection points of the switching elements constituting the pair of switching elements Chino is characterized in that it has a voltage dividing circuit part for dividing the at least one.

  Since the inverter device according to the present invention includes the clamp circuit unit that clamps the potential at the anode side connection point of the diode to the potential of the high-voltage side reference terminal, and the charging circuit unit that includes a capacitive element connected in parallel to the diode. A negative surge exceeding the design standard is not applied to the high voltage IC that drives and controls the switching element, and breakdown and malfunction of the high voltage IC can be prevented.

  In addition, the inverter device according to the present invention includes a clamp circuit unit that is configured by a parallel body of a plurality of diodes and clamps the potential at the anode side connection point of the plurality of diodes to the potential of the high-voltage side reference terminal. A negative surge exceeding the design standard is not applied to the high voltage IC that drives and controls the high voltage IC, and breakdown and malfunction of the high voltage IC can be prevented.

Embodiment 1 FIG.
FIG. 1 is a circuit diagram of an inverter device according to Embodiment 1 for carrying out the present invention. In FIG. 1, a three-phase inverter device is shown as an example. In FIG. 1, a three-phase inverter device 1 includes six switching elements T1 to T6 including elements having a switching function such as an IGBT (Insulated Gate Bipolar Transistor) and a MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor). A voltage type inverter 2 that is an inverter circuit composed of diodes D1 to D6 connected in antiparallel to the switching elements T1 to T6, respectively, and an inverter drive circuit 3 that drives the voltage type inverter 2 are provided.

  In the voltage type inverter 2, the switching elements T1, T3, T5 constitute an upper arm (positive arm), and the switching elements T2, T4, T6 constitute a lower arm (negative arm). Each collector of the switching elements T1, T3, and T5 is connected to a power supply terminal P that applies a positive power supply voltage to the voltage type inverter 2. The emitters of the switching elements T2, T4, and T6 are connected to a power supply terminal N that applies a negative power supply voltage to the voltage type inverter 2, respectively. The voltage type inverter 2 is an inverter circuit that is connected between a power supply terminal P and a power supply terminal N that are between positive and negative electrodes of a DC power supply, and is configured by at least one pair of switching elements.

  The emitter of the switching element T1 and the collector of the switching element T2 are connected to the U-phase output terminal U of the voltage type inverter 2, respectively. Similarly, the emitter of switching element T3 and the collector of switching element T4 are each connected to the V-phase output terminal V of voltage type inverter 2, and the emitter of switching element T5 and the collector of switching element T6 are respectively W of voltage type inverter 2. It is connected to the phase output terminal W. Further, the gates of the switching elements T1 to T6 are connected to the inverter drive circuit 3 via resistors R1 to R6, which are corresponding gate resistors. The inverter drive circuit 3 performs switching control of the switching elements T1 to T6 according to a control signal input from the outside.

  The inverter drive circuit 3 includes a high voltage IC 4, a protection circuit 5, floating power supplies 6 to 8, and a constant voltage diode D 10, which are drive circuits in which the reference potential of the input signal and the reference potential of the output signal are different. The high voltage IC 4 is an IC (Integrated Circuit) that drives the switching elements T1 to T6 of the voltage source inverter 2. The protection circuit 5 is connected in parallel to the U-phase clamp diode D7, the V-phase clamp diode D8, the W-phase clamp diode D9, and the clamp diodes D7 to D9 of each phase, which are diodes constituting the clamp circuit section. It is comprised by the capacitive elements C1-C3 which are charging circuit parts, and the impedance element Z1 which is a voltage dividing circuit part.

  The anodes of the clamp diodes D7 to D9 are respectively connected to a common point F connected to the low voltage side reference terminal VS0 of the high voltage IC4. The cathodes of the clamp diodes D7 to D9 are connected to correspond to the high-voltage side reference terminals VS1 to VS3 of the respective phases of the high voltage IC4. The clamp diodes D7 to D9 have a common point that is a cathode connected to the high-voltage side reference terminals VS1 to VS3 to which a potential serving as a reference of a signal on the high potential side of the high voltage IC 4 that is a driving circuit is applied, and is an anode side connection point. The potential of F is clamped to the potential of the high-voltage side reference terminals VS1 to VS3.

  Next, the impedance element Z1 will be described. The impedance element Z1 is connected between a common point F that is an anode side connection point of the clamp diodes D7 to D9 and a power supply terminal N that is a negative electrode of the DC power supply. The impedance element Z1 is connected to the cathode side connection points of the clamp diodes D7 to D9 of each phase and the output terminals U and V of the respective phases which are also connection points of the pair of switching elements T1 and T2, T3 and T4, T5 and T6. , W may be connected to each other, or between the common point F and the power supply terminal N, the cathode side connection points of the clamp diodes D7 to D9 of each phase, and the output terminals U, V, W of each phase May be connected simultaneously to both locations.

  FIG. 2 shows an example of a circuit diagram of the impedance element Z1. The impedance element Z1, which is a voltage dividing circuit section, may be constituted by a parallel body of a resistor R0 and a diode D0 as shown in FIG. 2A, or an inductor L0 and a diode as shown in FIG. You may comprise by the parallel body with D0, and if it has the function to divide and the function to bypass, you may comprise by another element which fulfill | performs each function. In the present embodiment, the diode used for the impedance element Z1 that is the voltage dividing circuit portion will be described separately from the clamp diodes D7 to D9. However, even if the diode of the impedance element Z1 and the clamp diode are the same type of diodes. Good. 2A and 2B, the cathode side of the diode D0 is configured to be connected to the power supply terminal N side of the voltage type inverter 2. This diode D0 bypasses the current so that the operating current of the high voltage IC 4 flowing from the low-voltage side reference terminal VS0 to the power supply terminal N is not restricted when the resistance value of the impedance element Z1 is large, which causes a problem with the operating current. It goes without saying that a diode for bypassing the operating current can be omitted as long as the resistance value does not affect the operating current. The low-voltage side reference terminal VS0 of the high withstand voltage IC4 is connected to the power supply terminal N through the impedance element Z1 and also connected to the VSS terminal of the high withstand voltage IC4 through the constant voltage diode D10. The VSS terminal is grounded.

  The high withstand voltage IC4 is different in the reference potential of the input signal and the reference potential of the output signal, and has three level shifters b2 to b4, upper arm side driver circuits b5 to b7, lower arm side driver circuits b8 to b10, overcurrent. A detector b11 and an error signal generator b12 are provided. The three level shifters b2 to b4 receive the output signals of the external control signal input terminals UPi, UNi, VPi, VNi, WPi, WNi, the input buffer b1, and the input buffer b1, and have floating potentials floating from the input signal potential. Generate a signal. The three upper arm driver circuits b5 to b7 receive the output signals of the level shifters b2 to b4 and drive the switching elements T1, T3, and T5 of the upper arms, respectively. The lower arm driver circuits b8 to b10 receive the three signals output from the input buffer b1, and drive the lower arm switching elements T2, T4, and T6, respectively. The overcurrent detector b11 detects an overcurrent. The error signal generator b12 receives the detection signal output from the overcurrent detector b11 and generates an error signal.

  The driver circuits b5 to b10 of the upper and lower arm switching elements output driving signals to the upper and lower arm switching elements T1 to T6 via the switching element driving signal output terminals UPo, VPo, WPo, UNo, VNo, and WNo. Corresponding floating power sources 6 to 8 are connected between the floating power source positive side input terminals VB1 to VB3 and the high voltage side reference terminals VS1 to VS3 of the upper arm side driver circuits b5 to b7, respectively. A positive voltage is applied from the DC power supply 9 to each of the lower arm driver circuits b8 to b10 through the positive power supply input terminal VCC, and is commonly connected to the low voltage reference terminal VS0.

  FIG. 3 is a circuit diagram showing the peripheral circuit of the high voltage IC 4 in FIG. 1 by extracting the main part for one phase of the U phase with the protection circuit 5 as the center. The operation of the protection circuit 5 will be described with reference to FIG. The negative surge generated between the high voltage side reference terminals VS1 to VS3 and the low voltage side reference terminal VS0 of the high voltage IC 4 due to switching of the switching elements T1 to T6 and external noise, and the impedance element Z1 and the clamp diode D7 of the protection circuit 5 To divide the pressure. Further, during the period until the clamp diode D7 reaches the ON voltage, the capacitive element C1 connected in parallel to the clamp diode D7 is charged. By such an operation, the negative voltage applied to the high voltage IC 4 can be reduced by charging the capacitive element C1 during the period until the clamp diode D7 reaches the ON voltage. Further, by giving the impedance element Z1 voltage characteristics that are equivalent to the forward transient voltage characteristics of the clamp diodes D7 to D9, the negative voltage applied to the high voltage IC 4 can be reduced.

  As described above, the three-phase inverter device 1 according to the present embodiment includes the capacitive elements C1 to C3 and the clamp diodes D7 to D9 together with the voltage division by the clamp diodes D7 to D9 and the impedance element Z1 of the protection circuit 5. The negative surge generated between the anodes and cathodes of the clamp diodes D7 to D9 can be suppressed to a low level by charging during the period until turning on. Since the negative surge can be kept small, the addition of a simple circuit ensures that the negative surge applied to the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 of the high voltage IC 4 is within the design criteria of the high voltage IC 4. It is possible to suppress the breakdown voltage and malfunction of the high voltage IC 4 at low cost. Furthermore, since it is not necessary to change the design of the high voltage IC, the present invention can be applied to an inverter device using the existing high voltage IC, and the breakdown of the high voltage IC of the existing device can be prevented.

Embodiment 2. FIG.
FIG. 4 is a circuit diagram of an inverter device according to Embodiment 2 for carrying out the present invention. The inverter device according to the present embodiment is different from the first embodiment in that a parallel body of a plurality of clamp diodes is connected instead of the configuration of the protection circuit in which capacitive elements are connected in parallel to the clamp diodes. 4, the same reference numerals as those in FIG. 1 denote the same or corresponding parts, and this is common throughout the entire specification. Moreover, the aspect of the component which appears in the whole specification is an illustration to the last, and is not limited to these description. Here, only differences from the first embodiment will be described.

  One cause of the occurrence of the negative surge is that it has a forward transient voltage during the period until the clamp diode connected between the high-voltage side reference terminals VS1 to VS3 of the high voltage IC 4 and the common point F becomes conductive. It is done. Since the magnitude of the forward transient voltage depends on the magnitude of the transient current flowing through the clamp diode, the transient current flowing through the clamp diode may be reduced in order to suppress the negative surge. Therefore, by connecting a plurality of clamp diodes in parallel, the transient current flowing through one clamp diode is reduced.

  In FIG. 4, the three-phase inverter device 10 includes a voltage type inverter 2 and an inverter drive circuit 11 that drives the voltage type inverter 2. The inverter drive circuit 11 includes a high voltage IC 4, a protection circuit 12, floating power supplies 6 to 8, and a constant voltage diode D 10. Here, since the configuration other than the protection circuit 12 such as the voltage type inverter 2 and the high voltage IC 4 is the same as that of the first embodiment, the description thereof is omitted.

  The protection circuit 12 includes a U-phase clamp diode D11 having a plurality of clamp diodes connected in parallel, a V-phase clamp diode D12 having a plurality of clamp diodes connected in parallel, and a W-phase clamp having a plurality of clamp diodes connected in parallel. A diode D13 and an impedance element Z1 are included. In each of the clamp diodes D11 to D13, the plurality of clamp diodes are connected in parallel so that the forward directions are the same. The number of clamp diodes constituting the clamp diodes D11 to D13 for each phase is not particularly limited as long as it is two or more. In FIG. 4, the clamp diodes D11 to D13 for each phase are composed of two clamp diodes connected in parallel. Is done.

  The anodes of the clamp diodes D11 to D13 are respectively connected to a common point F connected to the low-voltage side reference terminal VS0 of the high voltage IC4. The cathodes of the clamp diodes D11 to D13 are connected to correspond to the high-voltage side reference terminals VS1 to VS3 of the respective phases of the high voltage IC4. Further, the low-voltage side reference terminal VS0 of the high withstand voltage IC4 is connected to the power supply terminal N through the impedance element Z1 and also connected to the high withstand voltage VSS terminal through the constant voltage diode D10.

  The impedance element Z1 is connected between the common point F and the power supply terminal N. Here, since the configuration example of the impedance element Z1 is the same as that of the first embodiment, the description thereof is omitted. However, as with the first embodiment, the impedance element Z1 is the cathode side of the clamp diodes D7 to D9 of each phase. You may connect between the connection point and the output terminals U, V, W of each phase, or between the common point F and the power supply terminal N and the cathode side connection points of the clamp diodes D7 to D9 of each phase. You may connect simultaneously to both locations between the output terminals U, V, and W of each phase.

  Next, the operation of the protection circuit 12 will be described. 4, the negative surge generated between the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 of the high withstand voltage IC 4 due to switching of the switching elements T1 to T6 and external noise is prevented. The voltage is divided by the impedance element Z1 and the clamp diodes D11 to D13, and the transient current is divided by a plurality of clamp diodes connected in parallel in the clamp diodes D11 to D13 of each phase. Since the magnitude of the negative surge depends on the current flowing through the clamp diodes D11 to D13, the negative surge at each of the clamp diodes D11 to D13 can be reduced by dividing the transient current.

  As described above, the inverter device according to the present embodiment includes the clamp diodes connected in parallel in the clamp diodes D11 to D13 of each phase together with the voltage division by the clamp diodes D11 to D13 and the impedance element Z1 of the protection circuit 12. By dividing the transient current, the transient current flowing in the clamp diode can be reduced, so that a negative surge generated between the anode and the cathode of the clamp diodes D11 to D13 can be suppressed to a low level.

  Since the negative surge can be kept small, the addition of a simple circuit ensures that the negative surge applied to the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 of the high voltage IC 4 is within the design criteria of the high voltage IC 4. It is possible to suppress the breakdown voltage and malfunction of the high voltage IC 4 at low cost. Furthermore, since it is not necessary to change the design of the high voltage IC, the present invention can be applied to an inverter device using the existing high voltage IC, and the effect of preventing the breakdown of the high voltage IC of the existing device. There is.

Embodiment 3 FIG.
FIG. 5 is a circuit diagram of an inverter device according to Embodiment 3 for carrying out the present invention. In the inverter device of the present embodiment, an impedance element Z2, which is a second voltage dividing circuit section that further divides the voltage applied to the clamp diode, is connected between the low-voltage side reference terminal VS0 and the common point F, and the protection circuit The point added to is different from the first embodiment.

  In FIG. 5, the three-phase inverter device 13 includes a voltage type inverter 2 and an inverter drive circuit 14 that drives the voltage type inverter 2. The inverter drive circuit 14 includes a high voltage IC 4, a protection circuit 15, floating power supplies 6 to 8, and a constant voltage diode D 10. Here, since the configuration other than the protection circuit 15 such as the voltage type inverter 2 and the high voltage IC 4 is the same as that of the first embodiment, the description thereof is omitted.

  The protection circuit 15 includes a U-phase clamp diode D7, a V-phase clamp diode D8, a W-phase clamp diode D9, capacitive elements C1 to C3 connected in parallel to the clamp diodes D7 to D9 of each phase, and an impedance. It is composed of elements Z1 and Z2. The anodes of the clamp diodes D7 to D9 are respectively connected to a common point F connected to the low voltage side reference terminal VS0 of the high voltage IC4. The cathodes of the clamp diodes D7 to D9 are connected to correspond to the high-voltage side reference terminals VS1 to VS3 of the respective phases of the high voltage IC4.

  The impedance element Z1 is connected between the common point F and the power supply terminal N. The impedance element Z2 is connected between the low voltage side reference terminal VS0 of the high voltage IC4 and the common point F which is the anode side connection point of the clamp diodes D7 to D9. Here, since other connection forms and configurations of the impedance element Z1 are the same as those of the first embodiment, description thereof will be omitted. The impedance element Z2 may be connected between the high-voltage side reference terminals VS1 to VS3 of each phase and the cathode side of the clamp diodes D7 to D9 of each phase, or the common point F with the low-voltage side reference terminal VS0. May be simultaneously connected to both of the terminals and between the high-voltage side reference terminals VS1 to VS3 of each phase and the cathode side of the clamp diodes D7 to D9 of each phase. The configuration in which the impedance element Z1 and the impedance element Z2 are connected may be combined with the configuration of the protection circuit other than the protection circuit 15 of the present embodiment.

  Similarly to the impedance element Z1, the impedance element Z2 has a configuration in which, for example, a diode connected to the low-voltage side reference terminal VS0 of the high voltage IC 4 whose anode is a drive circuit and a resistor or inductor are connected in parallel. As long as the impedance element Z2 has a function of dividing voltage and a function of bypassing, the impedance element Z2 may not be a structure in which a diode and a resistor or an inductor are connected in parallel, but may be composed of other elements that perform the respective functions. In the present embodiment, the diode used for the impedance element Z2, which is the second voltage dividing circuit section, will be described separately from the clamp diodes D7 to D9. However, the diode of the impedance element Z2 and the clamp diode are the same type of diode. It may be. The low-voltage side reference terminal VS0 of the high withstand voltage IC4 is connected to the power supply terminal N through the impedance element Z2 and the impedance element Z1, and is connected to the VSS terminal of the high withstand voltage IC4 through the constant voltage diode D10. Yes.

  Since the impedance element Z2 has a forward transient voltage when a transient current flows from the impedance element Z1 side, the low voltage of the high withstand voltage IC 4 so as to cancel the negative surge generated between the anode and the cathode of the clamp diodes D7-9. By varying the potential of the side reference terminal VS0, the voltage difference generated between the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 can be suppressed, and the negative surge can be suppressed small. Further, by connecting the impedance element Z2, the voltage applied to the clamp diodes D7 to D9 can be further divided, so that the negative surge can be suppressed small. Since the protective circuit 15 has an effect of reducing the negative surge as described in the first embodiment, the negative surge can be further reduced by connecting the impedance element Z2.

  As described above, the three-phase inverter device 13 in the present embodiment includes the capacitive elements C1 to C3 and the clamp diodes D7 to D9 together with the voltage division by the clamp diodes D7 to D9 and the impedance element Z1 of the protection circuit 15. By performing the charging until it is turned on, the negative surge generated between the anodes and the cathodes of the clamp diodes D7 to D9 can be suppressed to be small. Further, the impedance element Z2 generates the voltage between the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 by changing the potential of the low-voltage side reference terminal VS0 corresponding to the voltage fluctuation in the clamp diodes D7 to D9. The voltage difference can be suppressed and the negative surge can be reduced.

  Since the negative surge can be kept small, the addition of a simple circuit ensures that the negative surge applied to the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 of the high voltage IC 4 is within the design criteria of the high voltage IC 4. It is possible to suppress the breakdown voltage and malfunction of the high breakdown voltage IC at low cost. Furthermore, since it is not necessary to change the design of the high voltage IC, the present invention can be applied to an inverter device using the existing high voltage IC, and the breakdown of the high voltage IC of the existing device can be prevented.

Embodiment 4 FIG.
FIG. 6 is a circuit diagram of an inverter device according to Embodiment 4 for carrying out the present invention. Although not specifically mentioned in the first embodiment, a Si (silicon) diode is generally used as a clamp diode constituting the protection circuit. In the inverter device according to the present embodiment, a SiC (silicon carbide) Schottky barrier diode is particularly used as the clamp diode.

  Unlike general PN junction or PIN (p-intrinsic-n) junction diodes, Schottky barrier diodes operate on the principle that charges are transferred by majority carriers, so that minority carriers accumulate on the junction surfaces that prevent switching. The high-speed switching is possible, and the generation of forward transient voltage due to a large transient current can be reduced. Further, by using SiC as a material, it is possible to obtain an excellent reverse withstand voltage, and it is possible to use in a high voltage circuit to which a Schottky barrier diode cannot be conventionally applied.

  6 differs from FIG. 1 in the first embodiment in that the clamp diodes D14 to D16 constituting the protection circuit 18 are SiC Schottky barrier diodes, and the impedance element Z2 is connected. The impedance element Z2 may not be connected. The three-phase inverter device 16 includes a voltage type inverter 2 and an inverter drive circuit 17 that drives the voltage type inverter 2. The inverter drive circuit 17 includes a high voltage IC 4, a protection circuit 18, floating power supplies 6 to 8, and a constant voltage diode D 10. Here, since the configuration other than the protection circuit 18 such as the voltage type inverter 2 and the high voltage IC 4 is the same as that of the first embodiment, the description thereof is omitted.

  The protection circuit 18 includes a U-phase clamp diode D14, a V-phase clamp diode D15, a W-phase clamp diode D16, capacitive elements C1 to C3 connected in parallel to the clamp diodes D14 to 16 of each phase, and an impedance. It is composed of elements Z1 and Z2. Each anode of the clamp diodes D14 to 16 is connected to a common point F connected to the low-voltage side reference terminal VS0 of the high voltage IC4. The cathodes of the clamp diodes D14 to D16 are connected so as to correspond to the high-voltage side reference terminals VS1 to VS3 of the respective phases of the high breakdown voltage IC4.

  The impedance element Z1 is connected between the common point F and the power supply terminal N. The impedance element Z2 is connected between the low voltage side reference terminal VS0 of the high voltage IC 4 and the common point F. Here, since other connection forms and configurations of the impedance element Z1 are the same as those of the first embodiment, description thereof will be omitted. Although not particularly limited, the clamp diodes D14 to D16 are constituted by two clamp diodes connected in parallel. The low-voltage side reference terminal VS0 of the high voltage IC 4 is connected to the power supply terminal N via the impedance element Z2 and the impedance element Z1, and is connected to the VSS terminal of the high voltage IC 4 via the impedance element Z2 and the constant voltage diode D10. It is connected.

  By configuring the protection circuit 18 in this manner, a negative surge generated between the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 of the high voltage IC 4 due to switching of the switching elements T1 to T6 or external noise, The voltage is divided by the impedance element Z1 of the protection circuit 18 and the clamp diodes D14 to D16, and the transient current is divided by the clamp diodes D14 to D16 connected in parallel. The capacitive elements C1 to C3 are charged during the period until the clamp diodes D14 to D16 reach the ON voltage. Further, the impedance element Z2 has a forward transient voltage when a transient current flows from the impedance element Z1 side, and the low voltage of the high voltage IC 4 corresponds to the voltage fluctuation generated between the anode and the cathode of the clamp diodes D14-16. By changing the potential of the side reference terminal VS0, the voltage difference generated between the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 can be suppressed, and the negative surge can be suppressed small.

  As described above, the three-phase inverter device 16 in the present embodiment connects the clamp diodes D14 to D16 and the capacitive elements C1 to C3 of the protection circuit 18 to connect the anodes and cathodes of the clamp diodes D14 to D16. The negative surge generated between the anodes and the cathodes of the clamp diodes D14 to D16 can be suppressed to a low level due to the high-speed switching characteristics of the SiC Schottky barrier diode. .

  Since the negative surge can be kept small, the addition of a simple circuit ensures that the negative surge applied to the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 of the high voltage IC 4 is within the design criteria of the high voltage IC 4. It is possible to suppress the breakdown voltage and malfunction of the high voltage IC 4 at low cost. Furthermore, since it is not necessary to change the design of the high voltage IC, the present invention can be applied to an inverter device using the existing high voltage IC, and the breakdown of the high voltage IC of the existing device can be prevented.

Embodiment 5 FIG.
FIG. 7 is a circuit diagram of an inverter device according to Embodiment 5 for carrying out the present invention. In the third and fourth embodiments, the impedance element Z2 is connected between the low voltage side reference terminal VS0 of the high voltage IC 4 and the anode side of the clamp diode, or the impedance element Z2 is connected to the high voltage side reference terminal VS1 of each phase. ~ VS3 and the cathode side of the clamp diode of each phase, respectively, or the impedance element Z2 is simultaneously connected to both of these two regions. The inverter device according to the present embodiment is different from the third embodiment in that a wiring having a desired resistance value or inductance having characteristics equivalent to those of the impedance element Z2 is provided and the impedance element Z2 is not disposed. Further, the present embodiment is different from the above embodiment in that the voltage type inverter and the protection circuit are integrated into a module, and the module and the high voltage IC are connected through wiring.

  In FIG. 7, the three-phase inverter device 19 includes a control circuit 20 and a module 22. The control circuit 20 includes a high voltage IC 4 and a DC power supply 9. The module 22 includes a voltage type inverter 2, a protection circuit 21, floating power supplies 6 to 8, and a constant voltage diode D10. Here, the configuration other than the protection circuit 21 such as the voltage type inverter 2 and the high voltage IC 4 and the wiring J1 is the same as that of the first embodiment, and thus the description thereof is omitted.

  Between the low-voltage side reference terminal VS0 of the high voltage IC 4 of the control circuit 20 and the common point F of the protection circuit 21 of the module 22, it has a characteristic equivalent to the impedance element Z2 as shown in the third embodiment. The designed wiring J1 is arranged. Here, the wiring J1 is functionally designed in terms of wiring shape and wiring length, and is made equivalent to a circuit configuration to which, for example, an inductor is added. As a result, the wiring J1 has a forward transient voltage. The low-voltage side reference terminal VS0 of the high withstand voltage IC4 is connected to the anodes of the clamp diodes D11 to D13 through the wiring J1, connected to the power supply terminal N through the impedance element Z1, and high through the constant voltage diode D10. It is connected to the VSS terminal of the withstand voltage IC4. In the control circuit 20, the high voltage IC 4 is a high voltage IC that drives the switching elements T <b> 1 to T <b> 6 of the voltage source inverter 2.

  The protection circuit 21 includes a U-phase clamp diode D11, a V-phase clamp diode D12, a W-phase clamp diode D13, capacitive elements C1 to C3 connected in parallel to the clamp diodes D11 to D13 of each phase, and an impedance. It is comprised by the element Z1. The anodes of the clamp diodes D11 to D13 are respectively connected to a common point F connected to the low-voltage side reference terminal VS0 of the high voltage IC4. The cathodes of the clamp diodes D11 to D13 are connected to correspond to the high-voltage side reference terminals VS1 to VS3 of the respective phases of the high voltage IC4. Although not particularly limited, in the present embodiment, the clamp diodes D11 to D13 are constituted by two clamp diodes connected in parallel. The impedance element Z1 is connected between the common point F and the power supply terminal N. Here, since other connection forms and configurations of the impedance element Z1 are the same as those in the first embodiment, description thereof will be omitted.

  By configuring the protection circuit 21 in this way, a negative surge generated between the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 of the high voltage IC 4 due to switching of the switching elements T1 to T6 and external noise, The voltage is divided by the impedance element Z1 of the protection circuit 21 and the clamp diodes D11 to D13, and the transient current is divided by the clamp diodes D11 to D13 in which a plurality of clamp diodes are connected in parallel. Further, the capacitive elements C1 to C3 are charged during the period until the clamp diodes D11 to D13 reach the ON voltage. A wiring J1 connecting the low-voltage side reference terminal VS0 and the anode side of each of the clamp diodes D11 to D13 has a characteristic equivalent to an impedance element such as a resistor or an inductor, and is between the anode and the cathode of the clamp diodes D11 to D13. The potential of the low-voltage side reference terminal VS0 of the high withstand voltage IC4 is varied in response to the voltage variation that occurs in FIG.

  As described above, the three-phase inverter device 19 in the present embodiment connects the clamp diodes D11 to D13 and the capacitive elements C1 to C3 of the protection circuit 21 to connect the anodes and cathodes of the clamp diodes D11 to D13. The negative surge generated between them can be kept small. Further, even when the voltage type inverter 2 and the protection circuit 21 are integrated into the module 22, the module 22 and the high voltage IC 4 are connected by the wiring J <b> 1 to cope with voltage fluctuations in the clamp diodes D <b> 11 to D <b> 13. By changing the potential of the low-voltage side reference terminal VS0, the voltage difference generated between the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 can be suppressed and the negative surge can be suppressed to be small.

  Since the negative surge can be suppressed to a low level, the addition of a simple circuit with a small number of elements allows the negative surge applied to the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 of the high voltage IC 4 to be designed for the high voltage IC 4 Therefore, it is possible to suppress the breakdown voltage and malfunction of the high breakdown voltage IC 4 at low cost. Furthermore, since it is not necessary to change the design of the high voltage IC, the present invention can be applied to an inverter device using the existing high voltage IC, and the breakdown of the high voltage IC of the existing device can be prevented.

  Note that the circuits corresponding to the control circuit 20 and the module 22 are not limited to being on the same substrate, and can be applied to a circuit including separate substrates.

Embodiment 6 FIG.
FIG. 8 is a circuit diagram of an inverter device according to the sixth embodiment for carrying out the present invention. The inverter device according to the present embodiment is different from the third embodiment in that the impedance elements Z1 and Z2 connected to the protection circuit in order to suppress negative surges are configured by diodes connected in parallel in opposite directions. .

  In FIG. 8, the three-phase inverter device 23 includes a voltage type inverter 2 and an inverter drive circuit 24 that drives the voltage type inverter 2. The inverter drive circuit 24 includes a high voltage IC 4, a protection circuit 25, floating power supplies 6 to 8, and a constant voltage diode D 10. Here, since the configuration other than the protection circuit 25 such as the voltage type inverter 2 and the high voltage IC 4 is the same as that of the first embodiment, the description thereof is omitted. In the inverter drive circuit 24, the high voltage IC 4 is a high voltage IC that drives the switching elements T <b> 1 to T <b> 6 of the voltage source inverter 2.

  The protection circuit 25 includes a U-phase clamp diode D11, a V-phase clamp diode D12, a W-phase clamp diode D13, capacitive elements C1 to C3 connected in parallel to the clamp diodes D11 to D13 of each phase, and an impedance. It is composed of elements Z1 and Z2. The anodes of the clamp diodes D11 to D13 are respectively connected to a common point F connected to the low-voltage side reference terminal VS0 of the high voltage IC4. The cathodes of the clamp diodes D11 to D13 are connected to correspond to the high-voltage side reference terminals VS1 to VS3 of the respective phases of the high voltage IC4. Although not particularly limited, in the present embodiment, the clamp diodes D11 to D13 are constituted by two clamp diodes connected in parallel. The low-voltage side reference terminal VS0 of the high voltage IC 4 is connected to the power supply terminal N via the impedance element Z2 and the impedance element Z1, and is also connected to the VSS terminal of the high voltage IC 4 via the constant voltage diode D10. .

  The impedance element Z1 which is a voltage dividing circuit unit is configured by diodes D17 and D18 connected in parallel in opposite directions, and is connected between the common point F and the power supply terminal N. The impedance element Z2 that is the second voltage dividing circuit unit is configured by diodes D19 and D20 connected in parallel in opposite directions, and is connected between the common point F and the low-voltage side reference terminal VS0 of the high voltage IC4. . Although the diodes used for the impedance elements Z1 and Z2 are described separately from the clamp diodes D11 to D13, the diodes of the impedance elements Z1 and Z2 may be the same type as the clamp diodes. The diode D18 and the diode D20 bypass the current so that the operating current of the high voltage IC 4 flowing from the low voltage side reference terminal VS0 of the high voltage IC 4 to the power supply terminal N is not limited. The diode D17 and the diode D19 are diodes having a characteristic that becomes a forward transient voltage larger than the forward transient voltage of the clamp diodes D11 to D13.

  By configuring the protection circuit 25 in this way, a negative surge generated between the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 of the high voltage IC 4 due to switching of switching elements or external noise is prevented. Is divided by the impedance element Z1 and the clamp diodes D11 to D13, and a transient current is divided by the clamp diodes D11 to D13 connected in parallel. Further, the capacitive elements C1 to C3 are charged during the period until the clamp diodes D11 to D13 reach the ON voltage. Further, D19 constituting the impedance element Z2 has a forward transient voltage when a transient current flows, and corresponds to the voltage fluctuation generated between the anodes and cathodes of the clamp diodes D11 to D13, and the low voltage side reference of the high voltage IC4. The potential of the terminal VS0 is changed. In addition, since the gate resistances of the switching elements T1 to T6 are determined by the impedance element Z1 and the gate resistances R1 to R6 of the switching elements T1 to T6, the range of selection of the resistance values of the gate resistances R1 to R6 may be narrowed. By using the diode D17 and the diode D19 for the impedance element Z1 and the impedance element Z2, the influence on the gate resistances R1 to R6 of the switching elements T1 to T6 can be minimized, and the degree of freedom of switching is increased. Can do.

  As described above, the three-phase inverter device 23 according to the present embodiment connects the clamp diodes D11 to D13 and the capacitive elements C1 to C3 of the protection circuit 25, thereby connecting the anode and the cathode of the clamp diodes D11 to D13. The negative surge generated between the clamp diodes D11 to D13 and the impedance element Z2 having a forward transient voltage larger than that of the clamp diodes D11 to D13 can be applied to the low-voltage side reference terminal VS0 in response to voltage fluctuations in the clamp diodes D11 to D13. By varying the potential, the voltage difference generated between the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 can be suppressed, and the negative surge can be reduced.

  Since the negative surge can be kept small, the addition of a simple circuit with a small number of elements allows the negative surge applied to the high-voltage side reference terminals VS1 to VS3 and the low-voltage side reference terminal VS0 of the high voltage IC 4 to be designed for the high voltage IC. Therefore, it is possible to suppress the breakdown voltage and malfunction of the high breakdown voltage IC 4 at low cost. Furthermore, since it is not necessary to change the design of the high voltage IC 4, the present invention can be applied to an inverter device using the existing high voltage IC, and destruction of the high voltage IC of the existing device can be prevented.

Embodiment 7 FIG.
FIG. 9 is a circuit diagram of an inverter device according to Embodiment 7 for carrying out the present invention. In this embodiment, the forward transient voltage of the high voltage IC, which is a drive circuit in which the reference potential of the input signal and the reference potential of the output signal are different, is larger than the forward transient voltage of the diode of the voltage-type inverter. did. In FIG. 9, the three-phase inverter device 26 includes a voltage type inverter 2 and an inverter drive circuit 27 that drives the voltage type inverter 2. The configuration of the inverter drive circuit 27 other than the high voltage IC 28 is the same as that of the first embodiment.

  In the three-phase inverter device 26, the voltage type inverter 2 includes switching elements T1 to T6 and diodes D1 to D6 connected in antiparallel to the switching elements T1 to T6, respectively. The high breakdown voltage IC 28 of the inverter drive circuit 27 is a high breakdown voltage IC that drives the switching elements T1 to T6 of the voltage type inverter 2. In such a configuration, when an extremely large current change di / dt occurs due to switching of the switching elements T1 to T6 or external noise, the high-voltage side reference terminal between the elements of the diodes D1 to D6 and the high-voltage IC 28 due to the transient current. Forward transient voltages are generated between the terminals VS1 to VS3 and the low-voltage side reference terminal VS0.

  Here, a description will be given focusing on the U phase of the three-phase inverter device 26. When the forward transient voltage generated in the high voltage IC 28 is smaller than the forward transient voltage generated in the diode D2 of the voltage type inverter 2, a negative surge is generated between the high voltage side reference terminal VS1 and the low voltage side reference terminal VS0 of the high voltage IC 28. Will occur. Therefore, the high voltage IC 28 is a high voltage IC having a characteristic that the forward transient voltage between the high voltage side reference terminal VS1 and the low voltage side reference terminal VS0 is larger than the forward voltage transient of the diode D2.

  Further, in order to clamp the potential of the low-voltage side reference terminal VS0 to the high-voltage side reference terminal VS1, the clamp is clamped so that the anode is connected to the low-voltage side reference terminal VS0 between the high-voltage side reference terminal VS1 and the low-voltage side reference terminal VS0. When the diode D7 is connected, the high voltage IC 28 has a forward transient voltage between the high-voltage side reference terminal VS1 and the low-voltage side reference terminal VS0, the forward transient voltage of the diode D2 and the forward transient of the clamp diode D7. A high breakdown voltage IC having characteristics that do not become the smallest compared with the voltage is obtained. Here, it is synonymous to select the diode D2 and the clamp diode D7 so that the forward transient voltage of the high voltage IC 28 is not minimized compared with the forward transient voltage of the diode D2 and the forward transient voltage of the clamp diode D7. Needless to say.

  For the V phase and W phase of the three-phase inverter device 26 as well as the U phase, forward transient voltages between the high-voltage side reference terminals VS2 and VS3 and the low-voltage side reference terminal VS0 of the high voltage IC 28 are diode D4 and D4, respectively. Compared with the forward transient voltage of D6 and the forward transient voltages of the clamp diodes D8 and D9, the characteristics are not minimized. By using such a high voltage IC 28, the three-phase inverter device 26 in the present embodiment can suppress a negative surge.

  Since the negative surge can be kept small, the addition of a simple circuit with a small number of elements allows the negative surge applied to the high voltage side reference terminals VS1 to VS3 and the low voltage side reference terminal VS0 of the high voltage IC 28 to be designed as a design standard for the high voltage IC 28. Therefore, it is possible to prevent the breakdown voltage and malfunction of the high breakdown voltage IC 28 at low cost. Furthermore, since it is not necessary to change the design of the high voltage IC, the present invention can be applied to an inverter device using the existing high voltage IC, and the breakdown of the high voltage IC of the existing device can be prevented.

  In the first to third and fifth to seventh embodiments, a configuration in which a general diode is used as the clamp diode has been described. However, the present invention is not limited to this, and the clamp diode shown in the fourth embodiment is not limited to SiC. A configuration using a Schottky barrier diode may also be used. In all the embodiments, a configuration using a general diode for the impedance elements Z1 and Z2 has been described. However, the configuration is not limited to this, and a configuration using a SiC Schottky barrier diode may be used.

  In all the embodiments, the three-phase inverter device has been described as an example. However, the present invention is not limited to this and can be applied to a single-phase inverter or the like. Furthermore, the protection circuit including two clamp diodes connected in parallel has been described as an example. However, the present invention is not limited to this, and the clamp diode is set to 1 according to the condition of a negative surge applied to the high voltage IC. Can be one or more.

It is a circuit diagram of the inverter apparatus in Embodiment 1 of this invention. It is a circuit diagram which shows an example of the impedance element in Embodiment 1 of this invention. It is a circuit diagram of the principal part for 1 phase of the inverter apparatus in Embodiment 1 of this invention. It is a circuit diagram of the inverter apparatus in Embodiment 2 of this invention. It is a circuit diagram of the inverter apparatus in Embodiment 3 of this invention. It is a circuit diagram of the inverter apparatus in Embodiment 4 of this invention. It is a circuit diagram of the inverter apparatus in Embodiment 5 of this invention. It is a circuit diagram of the inverter apparatus in Embodiment 6 of this invention. It is a circuit diagram of the inverter apparatus in Embodiment 7 of this invention.

Explanation of symbols

  1, 10, 13, 16, 19, 23, 26 3-phase inverter device, 2-voltage inverter, 3, 11, 14, 17, 24, 27 Inverter drive circuit, 4, 28 High voltage IC, 5, 12, 15 , 18, 21, 25 Protection circuit, 6 to 8 floating power supply, 9 DC power supply, 20 control circuit, 22 modules, D0, D17 to D20 impedance element diode, D1 to D6 diode, C1 to C3 capacitive element, D7 to D9, D11 to D13 Clamp diode, D10 constant voltage diode, D14 to D16 clamp diode (SiC Schottky barrier diode), J1 special wiring, N, P power supply terminal, T1 to T6 switching element, U, V, W output terminal, Z1, Z2 Impedance elements.

Claims (13)

An inverter circuit connected between the positive and negative electrodes of a DC power source and configured by at least one pair of switching elements;
A drive circuit in which a reference potential of an input signal and a reference potential of an output signal are different, and an inverter drive circuit that drives the switching element;
The inverter drive circuit is configured by a diode having a cathode connected to a high-voltage side reference terminal to which a potential serving as a reference of a signal on the high potential side of the drive circuit is applied, and the potential at the anode side connection point of the diode is A clamp circuit for clamping to the potential of the high-voltage side reference terminal;
A charging circuit unit composed of a capacitive element connected in parallel to the diode;
At least one of the connection point between the anode side of the diode and the negative electrode of the DC power supply, and the connection point between the cathode side connection point of the diode and each switching element constituting the pair of switching elements An inverter device comprising: a voltage dividing circuit section that divides one side. The inverter device according to claim 1, wherein the diode of the clamp circuit unit includes a parallel body of a plurality of diodes. An inverter circuit connected between the positive and negative electrodes of a DC power source and configured by at least one pair of switching elements;
A drive circuit in which a reference potential of an input signal and a reference potential of an output signal are different, and an inverter drive circuit that drives the switching element;
The inverter drive circuit is configured by a parallel body of a plurality of diodes having a cathode connected to a high-voltage side reference terminal to which a potential serving as a reference of a signal on the high potential side of the drive circuit is applied, and anodes of the plurality of diodes A clamp circuit section for clamping the potential of the side connection point to the potential of the high-voltage side reference terminal;
Between the anode side connection point of the plurality of diodes and the negative electrode of the DC power supply, and between the cathode side connection point of the plurality of diodes and the connection point of each switching element constituting the pair of switching elements An inverter device comprising: a voltage dividing circuit section that divides at least one of the voltage dividing circuits. Voltage-dividing at least one of the anode-side connection point of the diode and the low-voltage side reference terminal of the drive circuit, and between the cathode-side connection point of the diode and the high-voltage side reference terminal of the drive circuit is divided. The inverter device according to claim 1, further comprising a second voltage dividing circuit unit. 5. The inverter device according to claim 4, wherein the second voltage dividing circuit portion is formed of a wiring having a forward transient voltage. The inverter device according to claim 4, wherein the second voltage dividing circuit unit includes a diode having an anode connected to the drive circuit side. The inverter device according to claim 4, wherein the second voltage dividing circuit unit includes diodes connected in parallel in opposite directions. 8. The inverter device according to claim 6, wherein the diode of the second voltage dividing circuit unit is formed of a SiC Schottky barrier diode. The inverter device according to any one of claims 1 to 8, wherein the voltage dividing circuit section includes a diode having a cathode connected to the inverter circuit side. The inverter device according to claim 1, wherein the voltage dividing circuit section includes diodes connected in parallel in opposite directions. 11. The inverter device according to claim 9, wherein the diode of the voltage dividing circuit unit includes a SiC Schottky barrier diode. The inverter device according to any one of claims 1 to 11, wherein the diode of the clamp circuit unit includes a SiC Schottky barrier diode. 13. The driving circuit generates a forward transient voltage larger than a forward transient voltage generated by the diode connected between the low-voltage reference terminal and the high-voltage reference terminal. The inverter device according to any one of the above.

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