Upper arm drive circuit, drive circuit of power conversion device, power conversion device

Abstract

In a power conversion device having a bridging circuit consisting of upper and lower arms, stable control of the upper arm is achieved without erroneous operation even when the output of the power conversion device becomes negative. An upper arm drive circuit for driving and controlling the upper arm switching element of the power conversion device is characterized by comprising: an upper arm gate voltage output wiring connected to the gate of the upper arm switching element; a first upper arm drive circuit reference potential wiring; an upper arm gate voltage reference potential wiring connected to the inverter output of the power conversion device; and an upper arm drive circuit reference potential wiring potential control circuit that controls the first upper arm drive circuit reference potential wiring to a potential lower than the reference potential when the inverter output is below a predetermined potential lower than the reference potential, wherein the first upper arm drive circuit reference potential wiring is connected to the reference potential via the upper arm drive circuit reference potential control circuit.

Description

Technical Field

[0001] This invention relates to the structure of a drive circuit for driving control of a power conversion device, and more particularly to an effective technique for use in the upper arm drive circuit of a power conversion device. Background Technology

[0002] With increasing global awareness of environmental protection, the demand for energy conservation has risen further, leading to the widespread adoption of power conversion devices (inverters) in various fields. Furthermore, in power conversion devices (inverters) installed in drive systems such as railway vehicles and air conditioning systems, achieving high performance, high efficiency, and high reliability has become crucial issues.

[0003] A typical power conversion device is constructed by a bridge circuit having upper and lower arms consisting of switching elements and return diodes connected in antiparallel to the switching circuit, and includes an upper arm drive circuit for driving and controlling the switching elements of the upper arm and a lower arm drive circuit for driving and controlling the switching elements of the lower arm.

[0004] As background technology in this field, there is, for example, technology like Patent Document 1. Patent Document 1 discloses the following circuit structure: a MOSFET for gate shorting is connected between the gate and emitter of the IGBT, and a capacitor is connected between the gate of the MOSFET and the collector of the IGBT, thereby turning on the MOSFET for gate shorting when a large voltage (dV / dt) with a sharp change is applied, thus short-circuiting the gate of the IGBT to prevent malfunction. (Paragraph

[0017] of Patent Document 1, etc.).

[0005] Furthermore, Patent Document 2 discloses the following circuit structure: By invalidating the pulse signals simultaneously appearing in the load resistors 3 and 4 of MOSFETs 1 and 2 as noise, such as noise caused by rapidly changing large voltages (dV / dt), erroneous operation of the RS latch 15 and the output IGBT 17 is prevented. (Paragraph

[0023] of Patent Document 2, etc.)

[0006] Patent documents

[0007] Patent Document 1: Japanese Patent Application Publication No. 8-88550

[0008] Patent Document 2: Japanese Patent Application Publication No. 2005-51821 Summary of the Invention

[0009] However, in typical power conversion devices like those described above, the reference potential of the upper arm drive circuit, which drives and controls the switching elements of the upper arm, is usually connected to GND (ground). When the inverter output potential of the power conversion device is negative, a voltage below the reference potential may sometimes be applied to the upper arm drive circuit, causing the upper arm drive circuit to malfunction due to reverse current flow.

[0010] The IGBT drive circuits in Patent Documents 1 and 2 are both configured to use GND (ground) as the reference potential, but the problems arising when the output potential is negative and their solutions are not described.

[0011] Therefore, the object of the present invention is to provide an upper arm drive circuit that, in a power conversion device having a bridge circuit composed of upper and lower arms, will not perform erroneous operation even when the output of the power conversion device is negative, and can perform stable control of the upper arm.

[0012] To address the aforementioned problem, the present invention provides an upper arm drive circuit that drives and controls the upper arm switching element of a power conversion device. The circuit comprises: an upper arm gate voltage output wiring connected to the gate of the upper arm switching element; a first upper arm drive circuit reference potential wiring; an upper arm gate voltage reference potential wiring connected to the inverter output of the conversion device; and an upper arm drive circuit reference potential wiring potential control circuit that, when the inverter output is below a predetermined potential lower than the reference potential, controls the first upper arm drive circuit reference potential wiring to a potential lower than the reference potential. The first upper arm drive circuit reference potential wiring is connected to the reference potential via the upper arm drive circuit reference potential wiring potential control circuit.

[0013] According to the present invention, an upper arm drive circuit can be implemented that, in a power conversion device having a bridge circuit composed of upper and lower arms, will not malfunction even when the output of the power conversion device becomes negative, and can perform stable control of the upper arm.

[0014] This enables the high reliability of power conversion devices (inverters).

[0015] Other issues, structures, and effects not mentioned above become clear through the following description of implementation methods. Attached Figure Description

[0016] Figure 1A This is a diagram showing the schematic structure of an existing power conversion device. (Prior Art 1)

[0017] Figure 1B This is a diagram showing the schematic structure of an existing power conversion device. (Prior Art 2)

[0018] Figure 2A This is a diagram showing the schematic structure of the power conversion device according to Embodiment 1 of the present invention.

[0019] Figure 2B It means Figure 2A A diagram of a variation. (Variation Example 1)

[0020] Figure 2C It means Figure 2B A diagram of a variation. (Variation Example 2)

[0021] Figure 3 This is a diagram showing the schematic structure of the power conversion device according to Embodiment 2 of the present invention.

[0022] Figure 4 This is a diagram showing the schematic structure of the power conversion device according to Embodiment 3 of the present invention.

[0023] Figure 5 This is a diagram showing the schematic structure of the power conversion device according to Embodiment 4 of the present invention.

[0024] Figure 6 This is a diagram showing the schematic structure of the power conversion device according to Embodiment 5 of the present invention.

[0025] Explanation of reference numerals in the attached figures

[0026] 1…Power conversion device

[0027] 2… Upper arm IGBT

[0028] 3… Upper arm return diode

[0029] 4…lower arm IGBT

[0030] 5…Lower arm return diode

[0031] 6… Upper arm drive circuit

[0032] 7…High-voltage power supply

[0033] 8…Inverter output

[0034] 9… Upper arm drive MOSFET

[0035] 10… Upper Arm Drive MOSFET

[0036] 11… resistor

[0037] 12… Upper arm drive circuit reference potential wiring

[0038] 13… Upper arm gate voltage output wiring

[0039] 14… Upper arm gate voltage reference potential wiring

[0040] 15… Reference Potential Wiring GND Connection

[0041] 16…Reference Potential Wiring Inverter Output Connection Section

[0042] 17… Upper arm drive circuit reference potential wiring

[0043] 18… Reference Potential Wiring GND Connection

[0044] 19…Reference Potential Wiring Inverter Output Connection Section

[0045] 20… Reference Potential Wiring GND Connection Section

[0046] 21… Reference Potential Wiring GND Connection Section

[0047] 22…Reference Potential Wiring Inverter Output Connection Section

[0048] 23… Reference potential wiring GND connection and reference potential wiring inverter output connection

[0049] 24… Upper arm drive circuit power wiring

[0050] 25, 26… resistors

[0051] 27,28…MOSFET

[0052] 29…Level shifting circuit for setting signal transmission

[0053] 30…Level shifting circuit for reset signal transmission

[0054] 31, 32… NOT circuit

[0055] 33…RS trigger

[0056] 34…High-side circuit

[0057] 35…Power supply for high-side circuit. Detailed Implementation

[0058] Hereinafter, embodiments of the present invention will be described using the accompanying drawings. Furthermore, in the drawings, the same structures are labeled with the same reference numerals, and detailed descriptions of repeated parts are omitted.

[0059] [Example 1]

[0060] First, refer to Figure 1A and Figure 1B The issues in the aforementioned existing power conversion devices will be described in detail. Figure 1A and Figure 1BThese are diagrams showing the schematic structure of existing power conversion devices, respectively representing structures equivalent to those in Patent Document 1 and Patent Document 2.

[0061] Furthermore, the lower arm drive circuit is omitted in the figures described below.

[0062] Furthermore, the invention is described using a half-bridge circuit as an example of the structure of a power conversion device (inverter), but it is not limited to this. It can also be applied to a power conversion device that has a full-bridge circuit with a bridge arm connected to another half-bridge circuit and a three-phase full-bridge circuit with an additional bridge arm. The half-bridge circuit is composed of only one bridge arm, which has a switching element at the top and bottom and a return diode connected in antiparallel to the switching element.

[0063] Prior Art 1

[0064] like Figure 1A As shown in Patent Document 1, the existing power conversion device 1 converts DC power supplied from the high-voltage power supply 7 into AC power through an upper arm consisting of an upper arm IGBT 2 and an upper arm return diode 3, and a lower arm consisting of a lower arm IGBT 4 and a lower arm return diode 5, and outputs it to the inverter output 8. The upper arm IGBT 2 is connected to the upper arm drive circuit 6 and is driven and controlled by the upper arm drive circuit 6.

[0065] The gate of the upper arm IGBT2 is connected to the drain side of the upper arm drive MOSFET10 of the upper arm drive circuit 6 via the upper arm gate voltage output wiring 13. The drain side of the upper arm drive MOSFET10 is connected to the inverter output 8 via the upper arm gate voltage reference potential wiring 14.

[0066] The gate of the upper arm drive MOSFET10 is connected to the drain side of the upper arm drive MOSFET9, and the source side of the upper arm drive MOSFET9 is connected to GND (ground) via resistor 11 and upper arm drive circuit reference potential wiring 12.

[0067] Here, the upper arm drive circuit reference potential wiring 12 is connected to GND. When the inverter output 8 is negative, a voltage below the reference potential is applied to the upper arm drive circuit 6. Therefore, due to reverse current, the upper arm drive circuit 6 may malfunction.

[0068] The details of this malfunction are explained below. The upper arm drive MOSFET 10 is a MOSFET used to turn off the upper arm IGBT 2, and it is only turned on when the upper arm IGBT 2 is off. When the upper arm IGBT 2 is on, the upper arm drive MOSFET 10 needs to be turned off. Therefore, turning on the upper arm drive MOSFET 9 discharges the gate charge of the upper arm drive MOSFET 10, lowering the gate potential of the upper arm drive MOSFET 10 and setting the voltage between the gate and source of the upper arm drive MOSFET 10 below 0V.

[0069] However, if the potential of inverter output 8 becomes negative, even if the upper arm drive MOSFET 9 is turned on, the gate potential of the upper arm drive MOSFET 10 cannot be reduced to below 0V. Therefore, there is a situation where applying voltage between the gate and source will cause the upper arm drive MOSFET 10 to turn on (erroneous operation).

[0070] Prior Art 2

[0071] like Figure 1B As shown in Patent Document 2, the conventional power conversion device 1 converts DC power supplied from the high-voltage power supply 7 into AC power through an upper arm consisting of an upper arm IGBT 2 and an upper arm return diode 3, and a lower arm consisting of a lower arm IGBT 4 and a lower arm return diode 5, and outputs it to the inverter output 8. The upper arm IGBT 2 is connected to the upper arm drive circuit 6 and is driven and controlled by the upper arm drive circuit 6.

[0072] The upper arm drive circuit 6 is configured to have a level shift circuit 29 for transmitting a set signal composed of a resistor 25 and a MOSFET 27, a level shift circuit 30 for transmitting a reset signal composed of a resistor 26 and a MOSFET 28, and a high-side circuit 34 composed of NOT circuits 31 and 32 and an RS flip-flop 33.

[0073] The gate of the upper arm IGBT2 is connected to the Q terminal of the RS flip-flop 33 of the upper arm drive circuit 6 via the upper arm gate voltage output wiring 13. The NOT circuits 31 and 32, the RS flip-flop 33, and the power supply 35 for the high-side circuit are connected to the inverter output 8 via the upper arm gate voltage reference potential wiring 14.

[0074] The source side of MOSFET27 and the source side of MOSFET28 are both connected to GND (ground) via the upper arm drive circuit reference potential wiring 12.

[0075] DC power is supplied from the high-side circuit power supply 35 via the upper arm drive circuit power supply wiring 24 and the upper arm gate voltage reference potential wiring 14 to the terminals on the resistor 25 side of the set signal transmission level shift circuit 29, the terminals on the resistor 26 side of the reset signal transmission level shift circuit 30, the NOT circuits 31 and 32 of the high-potential side circuit 34, and the RS flip-flop 33.

[0076] The basic operation of this circuit is explained. When the upper arm IGBT2 is turned on, the set signal is transmitted to the S terminal of the RS flip-flop 33 via the set signal transmission level shift circuit 29 and the NOT circuit 31. The RS flip-flop 33 holds the set signal, thereby turning on the upper arm IGBT2.

[0077] RS flip-flop 33 continues to hold the set signal until a reset signal is transmitted. During this period, upper arm IGBT2 remains on.

[0078] When the upper arm IGBT2 is disconnected, the reset signal is transmitted to the R terminal of the RS flip-flop 33 via the reset signal transmission level shift circuit 30 and the NOT circuit 32. The RS flip-flop 33 holds the reset signal, thereby disconnecting the upper arm IGBT2.

[0079] RS flip-flop 33 continues to hold the reset signal until the set signal is transmitted. During this period, upper arm IGBT2 remains in the off state.

[0080] In this circuit structure, when the potential of the inverter output 8 is negative, the upper arm drive circuit 6 may sometimes malfunction.

[0081] As a specific example of malfunction, when the potential of the inverter output 8 becomes negative, if a set signal is transmitted, sometimes it is impossible to transmit the signal from the set signal to the NOT circuit 31 via the level shift circuit 29.

[0082] This is because even if the inverter output 8, which serves as the reference potential for the NOT circuit 31, outputs an "L" signal using the level shift circuit 29 to transmit the set signal, it cannot be recognized as an "L" signal because the potential of the inverter output 8 is lower.

[0083] In addition, other specific examples of malfunctions include the following: when the potential of the inverter output 8 increases to become negative, and the potential of the upper arm drive circuit power supply line 24 is also negative, a reverse current is generated in the level shift circuit 29 for setting signal transmission and the level shift circuit 30 for resetting signal transmission, which is the current flowing from GND through the upper arm drive circuit reference potential line 12 to the upper arm drive circuit power supply line 24. The circuit becomes abnormal, thus causing a malfunction.

[0084] Next, refer to Figures 2A to 2CThe power conversion device and upper arm drive circuit involved in Embodiment 1 of the present invention will be described. Figure 2A This is a diagram showing the schematic structure of the power conversion device 1 in this embodiment. Figure 2B yes Figure 2A A variation (Variation 1). Figure 2C yes Figure 2B A variation (Variation 2).

[0085] also, Figure 2A This invention is applied to the prior art 1 described above. Figure 1A Example of the structure of the upper arm drive circuit, Figure 2B and Figure 2C This invention is applied to the prior art 2 described above. Figure 1B Example of the structure of the upper arm drive circuit.

[0086] like Figure 2A As shown, in this embodiment, the power conversion device 1 converts the DC power supplied from the high-voltage power supply 7 into AC power through an upper arm consisting of an upper arm IGBT 2 and an upper arm return diode 3 (which serve as switching elements), and a lower arm consisting of a lower arm IGBT 4 and a lower arm return diode 5 (which also serve as switching elements), and outputs the AC power to the inverter output 8. The upper arm IGBT 2 is connected to the upper arm drive circuit 6 and is driven and controlled by the upper arm drive circuit 6.

[0087] The gate of the upper arm IGBT2 is connected to the drain side of the upper arm drive MOSFET10 in the upper arm drive circuit 6 via the upper arm gate voltage output wiring 13. The drain side of the upper arm drive MOSFET10 is connected to the inverter output 8 via the upper arm gate voltage reference potential wiring 14.

[0088] The gate of the upper arm drive MOSFET 10 is connected to the drain side of the upper arm drive MOSFET 9. The source side of the upper arm drive MOSFET 9 is connected to the reference potential GND (ground) via resistor 11, upper arm drive circuit reference potential wiring 12, and reference potential wiring GND connection portion 15. In addition, the upper arm drive circuit 6 is connected to GND (ground) via upper arm drive circuit reference potential wiring 17, which is different from upper arm drive circuit reference potential wiring 12.

[0089] The upper arm gate voltage reference potential wiring 14 is connected to the upper arm drive circuit reference potential wiring 12 via the reference potential wiring inverter output connection part 16.

[0090] In this embodiment, the upper arm drive circuit reference potential wiring 12 is connected to the reference potential wiring GND connection part 15 and the reference potential wiring inverter output connection part 16.

[0091] Therefore, when the voltage of the inverter output 8 is normally above 0V, the voltage of the upper arm drive circuit reference voltage line 12 is set to a voltage equal to or higher than the reference voltage, such as approximately the same as GND, through the reference voltage line GND connection part 15.

[0092] In addition, when the potential of the inverter output 8 is below a predetermined potential lower than the reference potential, for example, it is negative, the potential of the upper arm drive circuit reference potential wiring 12 is set to a potential lower than the reference potential, for example, a potential approximately the same as the inverter output 8, through the reference potential wiring inverter output connection part 16.

[0093] That is, the upper arm drive circuit reference potential wiring control circuit is formed by the reference potential wiring GND connection part 15 and the reference potential wiring inverter output connection part 16. Furthermore, the upper arm drive circuit reference potential wiring 12 is connected to the reference potential via the upper arm drive circuit reference potential wiring control circuit (reference potential wiring GND connection part 15). Thus, when the inverter output 8 is below a predetermined potential lower than the reference potential, the upper arm drive circuit reference potential wiring control circuit controls the upper arm drive circuit reference potential wiring 12 to a potential lower than the reference potential.

[0094] This action prevents the upper arm drive circuit 6 from malfunctioning when the inverter output 8 has a negative potential.

[0095] In addition, Figure 2A In the example, the upper arm drive circuit reference potential wiring of the upper arm drive circuit 6 is divided into upper arm drive circuit reference potential wiring 12 (first upper arm drive circuit reference potential wiring) and upper arm drive circuit reference potential wiring 17 (second upper arm drive circuit reference potential wiring). Only upper arm drive circuit reference potential wiring 12 is connected to the reference potential wiring GND connection part 15 and the reference potential wiring inverter output connection part 16. However, it is possible to not distinguish between upper arm drive circuit reference potential wiring and to configure upper arm drive circuit reference potential wiring 12 and upper arm drive circuit reference potential wiring 17 into one upper arm drive circuit reference potential wiring, and connect it to the reference potential wiring GND connection part 15 and the reference potential wiring inverter output connection part 16.

[0096] Variation Example 1

[0097] use Figure 2B ,right Figure 2A The following are examples of variations.

[0098] also, Figure 2B The structure of the upper arm drive circuit 6 is similar to that of the prior art 2. Figure 1B The structure described in the previous section is the same, so detailed explanations are omitted.

[0099] exist Figure 2B In the power conversion device 1 shown, the upper arm drive circuit reference potential wiring connected to the set signal transmission level shift circuit 29 and the upper arm drive circuit reference potential wiring connected to the reset signal transmission level shift circuit 30 are not separately connected to GND, but are configured as one upper arm drive circuit reference potential wiring 12, which is connected to the reference potential wiring GND connection part 15 and the reference potential wiring inverter output connection part 16.

[0100] Therefore, when the potential of the inverter output 8 becomes negative, the reference potentials of the level shift circuit 29 for setting signal transmission and the level shift circuit 30 for resetting signal transmission become approximately the same as the potential of the inverter output 8, thus preventing erroneous operation that occurs in the prior art 2.

[0101] Variation Example 2

[0102] use Figure 2C ,right Figure 2B The following are examples of variations.

[0103] exist Figure 2B In this circuit, the reference potential wiring of the upper arm drive circuit connected to the level shift circuit 29 for setting signal transmission and the reference potential wiring of the upper arm drive circuit connected to the level shift circuit 30 for resetting signal transmission are not distinguished, but are instead set as a single upper arm drive circuit reference potential wiring 12. In contrast, in Figure 2C The upper arm drive circuit is configured as a reference potential line 12 connected to the level shift circuit 29 for transmitting the set signal and a reference potential line 17 connected to the level shift circuit 30 for transmitting the reset signal.

[0104] Furthermore, the upper arm drive circuit reference potential wiring 12, which is connected to the level shifting circuit 29 for transmitting the set signal, is connected to the reference potential wiring GND connection part 15 and the reference potential wiring inverter output connection part 16.

[0105] When the voltage at inverter output 8 is negative, the upper arm IGBT2 is usually disconnected.

[0106] Therefore, the next signal transmission is a set signal. As long as the erroneous operation of the level shifting circuit 29 for setting signal transmission is prevented, the upper arm drive circuit reference potential line 17 connected to the level shifting circuit 30 for reset signal transmission is directly connected to GND. Only the upper arm drive circuit reference potential line 12 of the level shifting circuit 29 for setting signal transmission is connected to the reference potential line GND connection part 15 and the reference potential line inverter output connection part 16, thereby becoming approximately the same potential as the inverter output 8, preventing erroneous operation.

[0107] [Example 2]

[0108] Reference Figure 3 The power conversion device and upper arm drive circuit involved in Embodiment 2 of the present invention will be described. Figure 3 This is a diagram showing the schematic structure of the power conversion device 1 in this embodiment.

[0109] also, Figure 3 Structure and Embodiment 1 of Upper Arm Drive Circuit 6 Figure 2A (Same as above, illustrations and detailed explanations omitted.)

[0110] like Figure 3 As shown, in the power conversion device 1 of this embodiment, the reference potential wiring GND connection part 18 and the reference potential wiring inverter output connection part 19 are respectively composed of diodes.

[0111] That is, in this embodiment, the upper arm drive circuit reference potential wiring line potential control circuit is configured to have: a first diode (18), which has a cathode connected to the reference potential side and an anode connected to the upper arm drive circuit reference potential wiring line 12 side; and a second diode (19), which has a cathode connected to the upper arm gate voltage reference potential wiring line (14) side and an anode connected to the upper arm drive circuit reference potential wiring line 12 side.

[0112] According to this structure, when the inverter output 8 is above 0V, the potential of the upper arm drive circuit reference potential wiring 12 becomes approximately the same as GND (in this example, a potential that is a certain amount higher than the reference potential corresponding to the diode threshold). When the inverter output 8 is negative, it becomes approximately the same as the inverter output 8 (in this example, a potential that is a certain amount higher than the inverter output 8 potential corresponding to the diode threshold). This prevents erroneous operation of the upper arm drive circuit 6.

[0113] Furthermore, an example is shown here where a diode is used for the reference potential wiring GND connection 18 and the reference potential wiring inverter output connection 19, but if it is a component or circuit that operates a rectifier that makes current flow in one direction, it may not be a diode.

[0114] [Example 3]

[0115] Reference Figure 4 The power conversion device and upper arm drive circuit involved in Embodiment 3 of the present invention will be described. Figure 4 This is a diagram showing the schematic structure of the power conversion device 1 in this embodiment.

[0116] Figure 4 Structure and Embodiment 1 of Upper Arm Drive Circuit 6 Figure 2A (Same as above, illustrations and detailed descriptions omitted)

[0117] like Figure 4As shown, in the power conversion device 1 of this embodiment, the reference potential wiring GND connection part 20 is composed of resistors, and the reference potential wiring inverter output connection part 19 is composed of diodes.

[0118] That is, in this embodiment, the upper arm drive circuit reference potential wiring line potential control circuit is configured to have: a resistor (20), one end of which is connected to the reference potential side and the other end of which is connected to the upper arm drive circuit reference potential wiring line 12 side; a diode (19), the cathode of which is connected to the upper arm gate voltage reference potential wiring line 14 side and the anode of which is connected to the upper arm drive circuit reference potential wiring line 12 side.

[0119] When the inverter output 8 has a potential above 0V, the current from the upper arm drive circuit 6 flows to the reference potential wiring GND connection 20. By suppressing this current value, if the voltage drop across the resistor decreases, the potential of the upper arm drive circuit reference potential wiring 12 becomes approximately the same as GND.

[0120] When the inverter output 8 is negative, the voltage of the reference voltage line 12 of the upper arm drive circuit becomes approximately the same as that of the inverter output 8 through the operation of the diode in the inverter output connection 19 of the reference voltage line.

[0121] Therefore, it is possible to prevent erroneous operation of the upper arm drive circuit 6.

[0122] [Example 4]

[0123] Reference Figure 5 The power conversion device and upper arm drive circuit involved in Embodiment 4 of the present invention will be described. Figure 5 This is a diagram showing the schematic structure of the power conversion device 1 in this embodiment.

[0124] Figure 5 Structure and Embodiment 1 of Upper Arm Drive Circuit 6 Figure 2A (Same as above, illustrations and detailed descriptions omitted.)

[0125] like Figure 5 As shown, in the power conversion device 1 of this embodiment, the reference potential wiring GND connection part 21 and the reference potential wiring inverter output connection part 22 are respectively composed of switches.

[0126] These switches can be mechanical switches like relays, or they can be semiconductor switching elements.

[0127] That is, in this embodiment, the upper arm drive circuit reference potential wiring line potential control circuit is configured to have: a first switch (21), one end of which is connected to the reference potential side and the other end of which is connected to the upper arm drive circuit reference potential wiring line 12 side; and a second switch (22), one end of which is connected to the upper arm gate voltage reference potential wiring line 14 side and the other end of which is connected to the upper arm drive circuit reference potential wiring line (12) side.

[0128] When the voltage of inverter output 8 is above 0V, the switch of reference voltage line GND connection 21 is turned on and the switch of reference voltage line inverter output connection 22 is turned off, thereby setting the voltage of upper arm drive circuit reference voltage line 12 to be approximately the same as GND (in this example, the same as the reference voltage).

[0129] When the inverter output 8 is negative, the switch of the reference potential wiring inverter output connection 22 is turned on, and the switch of the reference potential wiring GND connection 21 is turned off, thereby setting the potential of the upper arm drive circuit reference potential wiring 12 to be approximately the same as the inverter output 8 (in this example, the potential is equal to the potential of the inverter output 8).

[0130] As a method to achieve the above action, for example, the following method is used: the circuit that detects the potential of the inverter output 8 is detected to determine whether the inverter output 8 is above 0V or negative, and the switch of the reference potential wiring GND connection part 21 and the reference potential wiring inverter output connection part 22 is controlled.

[0131] Therefore, it is possible to prevent erroneous operation of the upper arm drive circuit 6.

[0132] [Example 5]

[0133] Reference Figure 6 The power conversion device and upper arm drive circuit involved in Embodiment 5 of the present invention will be described. Figure 6 This is a diagram showing the schematic structure of the power conversion device 1 in this embodiment.

[0134] Figure 6 Structure and Embodiment 1 of Upper Arm Drive Circuit 6 Figure 2A (Same as above, illustrations and detailed explanations omitted.)

[0135] In Example 4 ( Figure 5 In this configuration, the reference potential wiring GND connection section 21 and the reference potential wiring inverter output connection section 22 are each composed of separate switches. In contrast, as shown below... Figure 6 As shown, in the power conversion device 1 of this embodiment, a switch (referred to as a switch with C contact and shunt contact, etc.) is used to combine the operation of the reference potential wiring GND connection part and the reference potential wiring inverter output connection part 23 into one.

[0136] That is, in this embodiment, the upper arm drive circuit reference potential wiring line potential control circuit is configured to have a switching switch that can switch the connection of the upper arm drive circuit reference potential wiring line 12 with any one of the reference potential and upper arm gate voltage reference potential wiring line 14.

[0137] In this embodiment, for example, the inverter output 8 can be detected to be above 0V or negative by a circuit that detects the potential of the inverter output 8, and the switch of the reference potential wiring GND connection and the reference potential wiring inverter output connection 23 can be controlled, thereby preventing the upper arm drive circuit 6 from malfunctioning.

[0138] Furthermore, the present invention is not limited to the described embodiments, but includes various modifications. For example, the described embodiments are examples that have been explained in detail to aid in understanding the present invention, and are not limited to having all the described structures. Additionally, a portion of the structure of one embodiment can be replaced with the structure of another embodiment, and the structure of another embodiment can be added to the structure of a certain embodiment. Furthermore, other structures can be added to, deleted from, or replaced in relation to a portion of the structure of each embodiment.

[0139] For example, it could be as in Example 2 ( Figure 3 As in Example 4, the reference potential wiring GND connection is constructed using diodes. Figure 5 The inverter output connection is composed of a switch forming a reference potential wiring.

[0140] In addition, compared to Example 1 Figure 2B , Figure 2C The upper arm drive circuit 6 described herein can also be configured as an upper arm drive circuit reference potential wiring potential control circuit, as in Embodiments 2 to 5. Alternatively, the upper arm drive circuit 6 can be configured as... Figure 2A , Figure 2B , Figure 2C Structures other than those described in the text.

[0141] Furthermore, this invention can be configured such that the upper arm drive circuit and the lower arm drive circuit are mounted on a single semiconductor chip as a gate driver IC. It can also be applied to a single-chip inverter IC consisting of a bridge arm (composed of upper and lower arms), an upper arm drive circuit, and a lower arm drive circuit mounted on a single semiconductor chip. It can also be applied to a multi-chip inverter IC obtained by mounting the upper arm drive circuit and the lower arm drive circuit on different semiconductor chips and combining them with a bridge arm. Finally, it can be applied to a multi-chip inverter IC obtained by mounting the upper arm drive circuit and the lower arm drive circuit on a single semiconductor chip and combining them with a bridge arm.

Claims

1. An upper arm drive circuit which drives and controls upper arm switching elements of a power conversion device, characterized by, The upper arm drive circuit includes: an upper arm gate voltage output line connected to a gate of the upper arm switching element; a first upper arm drive circuit reference potential line; an upper arm gate voltage reference potential line connected to an inverter output of the power conversion device; an upper arm drive circuit reference potential line potential control circuit that controls the first upper arm drive circuit reference potential line to a potential lower than a reference potential when the inverter output is lower than a predetermined potential lower than the reference potential, the first upper arm drive circuit reference potential line is connected to the reference potential via the upper arm drive circuit reference potential line potential control circuit, the upper arm drive circuit includes: a first upper arm drive MOSFET whose drain side is connected to the gate of the upper arm switching element via the upper arm gate voltage output line, and whose source side is connected to the inverter output via the upper arm gate voltage reference potential line; a second upper arm drive MOSFET whose gate is connected to the drain side of the first upper arm drive MOSFET, and whose source side is connected to the first upper arm drive circuit reference potential line via a resistor.

2. The upper arm drive circuit according to claim 1, wherein the upper arm drive circuit reference potential line potential control circuit controls the first upper arm drive circuit reference potential line to a potential equal to or higher than the reference potential when the inverter output is higher than the predetermined potential.

3. The upper arm drive circuit according to claim 1, wherein the upper arm drive circuit reference potential line potential control circuit has a rectifier that causes current to flow in one direction.

4. The upper arm drive circuit according to claim 1, wherein the upper arm drive circuit reference potential line potential control circuit has: a first diode whose cathode is connected to the reference potential side, and whose anode is connected to the first upper arm drive circuit reference potential line side; a second diode whose cathode is connected to the upper arm gate voltage reference potential line side, and whose anode is connected to the first upper arm drive circuit reference potential line side.

5. The upper arm drive circuit according to claim 1, wherein the upper arm drive circuit reference potential line potential control circuit includes: a resistor whose one end is connected to the reference potential side, and whose other end is connected to the first upper arm drive circuit reference potential line side; a diode whose cathode is connected to the upper arm gate voltage reference potential line side, and whose anode is connected to the first upper arm drive circuit reference potential line side.

6. The upper arm drive circuit according to claim 1, wherein the upper arm drive circuit reference potential line potential control circuit has: a first switch whose one end is connected to the reference potential side, and whose other end is connected to the first upper arm drive circuit reference potential line side; a second switch whose one end is connected to the upper arm gate voltage reference potential line side, and whose other end is connected to the first upper arm drive circuit reference potential line side.

7. The upper arm drive circuit according to claim 1, wherein The upper arm drive circuit reference potential wiring potential control circuit has a switching switch that can switch connection of the first upper arm drive circuit reference potential wiring to either of the reference potential and the upper arm gate voltage reference potential wiring.

8. The upper arm drive circuit according to claim 1, characterized in that The upper arm drive circuit has a second upper arm drive circuit reference potential wiring connected to the reference potential and not connected to the upper arm drive circuit reference potential wiring potential control circuit.

9. A drive circuit of a power conversion device, characterized in that The drive circuit comprises: an upper arm drive circuit that drives and controls an upper arm switching element of the power conversion device; a lower arm drive circuit that drives and controls a lower arm switching element of the power conversion device, the upper arm drive circuit is the upper arm drive circuit according to any one of claims 1 to 8.

10. A power conversion device, characterized by, comprises: a bridge arm that has arms composed of switching elements and freewheel diodes connected in anti-parallel to the switching elements above and below; an upper arm drive circuit that drives and controls switching elements of the upper arm; a lower arm drive circuit that drives and controls switching elements of the lower arm, the upper arm drive circuit is the upper arm drive circuit according to any one of claims 1 to 8.

11. The power conversion device according to claim 10, characterized in that The upper arm drive circuit and the lower arm drive circuit are mounted on different semiconductor chips.

12. The power conversion device according to claim 10, characterized in that The upper arm drive circuit and the lower arm drive circuit are mounted on one semiconductor chip.

13. The power conversion device according to claim 10, characterized in that The bridge arm, the upper arm drive circuit, and the lower arm drive circuit are mounted on one semiconductor chip.

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