Power Conversion Equipment

Abstract

To provide a power conversion device capable of controlling an induction voltage even if a power supply circuit fails.SOLUTION: The present invention provides a power conversion device 100 comprising: a semiconductor element that converts electric power supplied from a strong power battery 1; a main power supply circuit 20; a slave power supply circuit 10; and power supply circuits 30, 40 configured to supply power not only from the main power supply circuit 20 but also from the slave power supply circuit 10 to a three-phase short circuit 22 and an over-voltage detection circuit 23. In a normal state, the semiconductor element is controlled by driving of a control circuit 21 on the basis of power from the main power supply circuit 20, and the over-voltage detection circuit 23 is driven on the basis of power from the main power supply circuit 20. In an over-voltage state, the three-phase short circuit 22 executes a three-phase short circuit control on the basis of power from one of the main power supply circuit 20 and the slave power supply circuit 30, and the over-voltage detection circuit 23 is driven on the basis of power from one of the main power supply circuit 20 and the slave power supply circuit 10.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a power conversion device. [Background technology]

[0002] Conventionally, there is known a power conversion device that consumes power by controlling switching elements to short-circuit three phases when an overvoltage state occurs due to a motor induced voltage. A control means that performs such control as suppressing overvoltage is usually operated by power supplied from a low-voltage power source (low-voltage battery) that is provided separately from a high-voltage power source (high-voltage battery) that supplies power for driving the motor.

[0003] Patent Document 1 discloses a power conversion device including a low-voltage power source that supplies power for control, and a power supply circuit that can supply the power for control based on the power supplied from a high-voltage battery. In this power conversion device, even if the low-voltage power source becomes abnormal, the power for control can be supplied from the power supply circuit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5433608 Summary of the Invention [Problem to be solved by the invention]

[0005] In the power conversion device described in Patent Document 1, if the power supply circuit fails, the control means that controls the switching elements is also turned off, making it impossible to control the induced voltage.

[0006] The present invention has been made in consideration of the above-mentioned problems, and has an object to provide a power conversion device that is capable of controlling an induced voltage even when a power supply circuit fails. [Means for solving the problem]

[0007] According to one aspect of the present invention, there is provided a power conversion device including a high-power battery, a low-power battery, a storage circuit for storing and smoothing DC power supplied from the high-power battery, a plurality of semiconductor elements for converting the DC power supplied from the high-power battery and the storage circuit into AC power for driving a motor, a control circuit for controlling the operation of the semiconductor elements, an overvoltage detection circuit for detecting an overvoltage in the storage circuit when the voltage of the storage circuit exceeds a reference voltage, and a three-phase short circuit for executing three-phase short circuit control using the semiconductor elements when the overvoltage detection circuit detects an overvoltage. The power conversion device includes a main power supply circuit connected to the low-power battery, a secondary power supply circuit connected to the high-power battery, and a power supply circuit configured to supply power to the three-phase short circuit and the overvoltage detection circuit not only from the main power supply circuit but also from the secondary power supply circuit. The plurality of semiconductor elements include a plurality of upper arm semiconductor elements connected to the positive electrode side of the high-power battery and a plurality of lower arm semiconductor elements connected to the negative electrode side of the high-power battery. In the normal state where no overvoltage is detected, the semiconductor element is controlled by driving the control circuit based on the power from the main power supply circuit, and the overvoltage detection circuit is driven based on the power from the main power supply circuit. On the other hand, when the overvoltage detection circuit detects an overvoltage, the three-phase short circuit turns on either the upper arm or the lower arm of the semiconductor element based on the power from either the main power supply circuit or the secondary power supply circuit, and turns off the other of the upper arms and the lower arms of the semiconductor element, and the overvoltage detection circuit is driven based on the power from either the main power supply circuit or the secondary power supply circuit. Effect of the Invention

[0008] According to the present invention, the power conversion device includes a power supply circuit configured to be able to supply power not only from a main power supply circuit but also from a sub power supply circuit to the three-phase short circuit and the overvoltage detection circuit. This makes it possible to execute three-phase short circuit control using power from the sub power supply circuit even if the main power supply circuit fails. In other words, it is possible to control the induced voltage even if the main power supply circuit (power supply circuit) fails. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a schematic configuration diagram of a power conversion device according to a first embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing a power converter in an overvoltage state. [Diagram 3] FIG. 3 is a diagram illustrating a slave power supply circuit. [Figure 4] FIG. 4 is a diagram showing a power supply circuit. [Diagram 5] FIG. 5 is a diagram showing a slave power supply circuit according to a modified example. [Figure 6] FIG. 6 is a diagram showing a power supply circuit according to a modified example. [Figure 7] FIG. 7 is a diagram showing a power supply circuit according to a modified example. [Figure 8] FIG. 8 is a schematic configuration diagram of a power conversion device according to the second embodiment. [Figure 9] FIG. 9 is a diagram illustrating the power conversion device when relay cut control is executed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0011] (First embodiment) 1 is a schematic configuration diagram of a power conversion device 100 according to a first embodiment of the present invention. The power conversion device 100 is mainly mounted on a vehicle.

[0012] The power conversion device 100 includes a high-power line connecting the high-power battery 1 with the storage circuit 11, the inverter 12 including a plurality of semiconductor elements, and the sub-power circuit 10, and a low-power line connecting the low-power battery 2 with the control circuit 21, the main power circuit 20, the three-phase short circuit 22, and the overvoltage detection circuit 23. The power conversion device 100 also includes a first power supply circuit 30 connected to the main power circuit 20 and the sub-power circuit 10 and having an output section connected to the three-phase short circuit 22, a second power supply circuit 40 connected to the main power circuit 20 and the sub-power circuit 10 and having an output section connected to the overvoltage detection circuit 23, and the like. The inverter 12 is connected to a drive motor (not shown).

[0013] The high-power battery 1 supplies power to the drive motor via the inverter 12 when the vehicle is driven, etc. During braking of the vehicle, regenerative current generated by the drive motor is supplied to the high-power battery 1 via the inverter 12, thereby charging the high-power battery 1. The high-power battery 1 is also connected to a secondary power supply circuit 10, which will be described later, so as to be able to supply power.

[0014] The storage circuit 11 is, for example, a smoothing capacitor, and is connected in parallel to the high-power battery 1 on a line connecting the high-power battery 1 and the inverter 12. The storage circuit 11 stores the regenerative current supplied from the inverter 12, smoothing the DC voltage of the high-power line (reducing the ripple voltage) and supplies it to the high-power battery 1.

[0015] The inverter 12 includes a plurality of upper arm semiconductor elements 12A connected to the positive electrode side of the high-power battery 1 and a plurality of lower arm semiconductor elements 12B connected to the negative electrode side of the high-power battery 1, and converts DC power supplied from the high-power battery 1 and the storage circuit 11 into AC power for driving the motor. Each semiconductor element of the inverter 12 is a switching element such as an IGBT (Insulated Gate Bipolar Transistor). The upper arm semiconductor element 12A and the lower arm semiconductor element 12B are connected in two stages in series between the positive electrode line and the negative electrode line of the high-power battery 1, and three series circuits in which the upper and lower arm semiconductor elements are connected in series are connected in parallel. Although not shown, the connection midpoints connecting the upper and lower arm semiconductor elements in each series circuit are connected to the U-phase coil, V-phase coil, and W-phase coil of the stator of the drive motor, respectively. Note that a freewheel diode (not shown) is connected between the collector and emitter of each semiconductor element of the inverter 12, with a cathode connected to the collector side and an anode connected to the emitter side.

[0016] The switching operation of each semiconductor element of the inverter 12 is controlled by a control circuit 21 described later. When a high gate signal is applied to the gate of a semiconductor element, the semiconductor element becomes conductive, and when a low gate signal is applied, the semiconductor element becomes non-conductive.

[0017] The slave power supply circuit 10 includes a transformer 10A (FIG. 3), with the primary coil side of the transformer 10A connected to the high-power battery 1 and the secondary coil side connected to the first power supply circuit 30 and the second power supply circuit 40. The slave power supply circuit 10 is driven by power supplied from the high-power battery 1, converts the voltage of the high-power line to a desired voltage, and supplies power to the first power supply circuit 30 and the second power supply circuit 40. The slave power supply circuit 10 is not activated in a normal state in which no overvoltage is detected, and is activated when an overvoltage detection circuit 23, described later, detects an overvoltage. Details of the slave power supply circuit 10 will be described later.

[0018] The low-power battery 2 is a battery with a lower voltage than the high-power battery 1, and supplies power to a signal generating circuit 21A of a control circuit 21 (described later), and also supplies power to a drive circuit 21C and an overvoltage detection circuit 23 of the control circuit 21 (described later) via a main power supply circuit 20. In other words, the low-power battery 2 is a battery that mainly supplies power to the control system.

[0019] The control circuit 21 is connected to the low-power battery 2 and serves as a control means for receiving power from the low-power battery 2 and controlling the operation of the semiconductor elements 12A and 12B of the inverter 12. The control circuit 21 is composed of a signal generating circuit 21A, a signal transmission circuit 21B, and a drive circuit 21C. The signal generating circuit 21A is connected to the low-power battery 2 and operates with power supplied from the low-power battery 2. The signal generating circuit 21A generates, for example, a PWM signal for driving a motor or extracting a regenerative current, and outputs the signal as a control signal to the signal transmission circuit 21B. The signal transmission circuit 21B transmits the control signal received from the signal generating circuit 21A to the drive circuit 21C. The drive circuit 21C operates with power supplied from the main power supply circuit 20, which will be described later, and turns on and off each of the semiconductor elements 12A and 12B at a predetermined timing based on the control signal input from the signal transmission circuit 21B. As a result, the DC current supplied from the high-power battery 1 is converted into AC current for driving the motor and output to the drive motor, and the regenerative current from the drive motor is converted into DC current and supplied to the high-power line.

[0020] It should be noted that the control circuit 21 is not limited to the above configuration as long as it can generate and output a control signal.

[0021] The main power supply circuit 20 includes a transformer, the primary coil side of which is connected to the low-power battery 2, and the secondary coil side is connected to the drive circuit (control circuit) 21C, the first power supply circuit 30, and the second power supply circuit 40. The main power supply circuit 20 operates by receiving power from the low-power battery 2, converting the voltage of the low-power line to a desired voltage, and outputting it. The main power supply circuit 20 operates both in a normal state and in an overvoltage state in which an overvoltage detection circuit 23 described later detects an overvoltage. As described later, the main power supply circuit 20 supplies power to the drive circuit (control circuit) 21C in a normal state and supplies power to the overvoltage detection circuit 23 via the second power supply circuit 40. On the other hand, in an overvoltage state, the main power supply circuit 20 supplies power to the three-phase short circuit 22 via the first power supply circuit 30, and supplies power to the overvoltage detection circuit 23 via the second power supply circuit 40.

[0022] The three-phase short circuit 22 is interposed between the control circuit 21 and the inverter 12, and is a circuit that executes three-phase short circuit control using the semiconductor elements 12A and 12B of the inverter 12 when an overvoltage detection circuit 23 described later detects an overvoltage. The three-phase short circuit 22 has a switch 22A that turns on or off the connection between the output part of the drive circuit 21C and the inverter 12, a switch 22B that turns on or off the connection between the output part of the first power supply circuit 30 and the semiconductor element 12A of the upper arm, and a switch 22C that turns on or off the connection between a ground (not shown) and the semiconductor element 12B of the lower arm. The switch 22A is provided on a line 221 that connects the drive circuit 21C and the semiconductor element 12A of the upper arm and on a line 222 that connects the drive circuit 21C and the semiconductor element 12B of the lower arm. When the switch 22A is in an on state, power is supplied from the drive circuit 21C to the inverter 12 via the three-phase short circuit 22. The switch 22B is provided on a line 223 that connects from the output section of the first power supply circuit 30 to a line 221 downstream of the switch 22A. When the switch 22B is in an on state, power is supplied to the inverter 12 (upper arm semiconductor element 12A) from the first power supply circuit 30 described later through the three-phase short circuit 22. The switch 22C is provided on a line 224 that connects the line 222 downstream of the switch 22A to the ground. Each of the switches 22A, 22B, and 22C of the three-phase short circuit 22 is configured to be able to receive an overvoltage detection signal from an overvoltage detection circuit 23 described later, and is switched on and off by application of the overvoltage detection signal. That is, the operation of each of the switches 22A, 22B, and 22C is controlled by the overvoltage detection circuit 23. The operation of the switches 22A, 22B, and 22C will be described in detail later.

[0023] The overvoltage detection circuit 23 is a circuit serving as a control means, and operates under normal conditions by receiving power supply from the main power supply circuit 20. The overvoltage detection circuit 23 detects the voltage of the high-power line (storage circuit 11), and when the voltage of the storage circuit 11 exceeds a reference voltage, it detects it as an overvoltage and outputs an overvoltage detection signal. The reference voltage here can be set, for example, to a voltage value that may exceed the withstand voltage of each component on the high-power line if the voltage continues to rise. When the overvoltage detection circuit 23 detects an overvoltage, it outputs an overvoltage detection signal to the secondary power supply circuit 10, the switches 22A, 22B, and 22C of the three-phase short circuit 22, the first power supply circuit 30, and the second power supply circuit 40.

[0024] In the first power supply circuit 30, a circuit connected to the main power supply circuit 20 and a circuit connected to the sub power supply circuit 10 are connected in parallel to the three-phase short circuit 22. A switch 30A is provided on the circuit connecting the main power supply circuit 20 to the three-phase short circuit 22, which connects or disconnects the main power supply circuit 20 and the three-phase short circuit 22. A switch 30B is provided on the circuit connecting the sub power supply circuit 10 to the three-phase short circuit 22, which connects or disconnects the sub power supply circuit 10 and the three-phase short circuit 22. The output section of the first power supply circuit 30 is connected to a line 223 on which a switch 22B of the three-phase short circuit 22 is provided. Therefore, when the switches 30A and 22B are turned on, the main power supply circuit 20 and the three-phase short circuit 22 are electrically connected, and when the switches 30B and 22B are turned on, the sub power supply circuit 10 and the three-phase short circuit 22 are electrically connected. That is, the first power supply circuit 30 is configured to be able to supply power to the three-phase short circuit 22 not only from the main power supply circuit 20 but also from the secondary power supply circuit 10. Each switch 30A, 30B of the first power supply circuit 30 is configured to be able to receive an overvoltage detection signal from the overvoltage detection circuit 23, and is switched on and off by application of the overvoltage detection signal. That is, the operation of each switch 30A, 30B is controlled by the overvoltage detection circuit 23. The operation of each switch 30A, 30B of the first power supply circuit 30 will be described in detail later.

[0025] In the second power supply circuit 40, a circuit connected to the main power supply circuit 20 and a circuit connected to the sub power supply circuit 10 are connected in parallel to the overvoltage detection circuit 23. A switch 40A is provided on the circuit connecting the main power supply circuit 20 to the overvoltage detection circuit 23, which connects or disconnects the main power supply circuit 20 and the overvoltage detection circuit 23. In addition, a switch 40B is provided on the circuit connecting the sub power supply circuit 10 to the overvoltage detection circuit 23, which connects or disconnects the sub power supply circuit 10 and the overvoltage detection circuit 23. When the switch 40A is turned on, the main power supply circuit 20 and the overvoltage detection circuit 23 are electrically connected, and when the switch 40B is turned on, the sub power supply circuit 10 and the overvoltage detection circuit 23 are electrically connected. In other words, the second power supply circuit 40 is configured to be able to supply power to the overvoltage detection circuit 23 not only from the main power supply circuit 20 but also from the sub power supply circuit 10. Each of the switches 40A, 40B of the second power supply circuit 40 is configured to be able to receive an overvoltage detection signal from the overvoltage detection circuit 23, and is switched on and off by application of the overvoltage detection signal. That is, each of the switches 40A, 40B is controlled by the overvoltage detection circuit 23. The operation of each of the switches 40A, 40B of the second power supply circuit 40 will be described in detail later.

[0026] Next, the switch control of the power conversion device 100 in a normal state and an overvoltage state will be described with reference to FIGS.

[0027] In a normal state where no overvoltage is detected by the overvoltage detection circuit 23, as shown in Fig. 1, the switch 22A of the three-phase short circuit 22 is on, and the switches 22B and 22C are off. Therefore, the on and off of each of the semiconductor elements 12A, 12B of the inverter 12 is controlled by the drive circuit 21C based on a control signal (PWM signal) from the signal generation circuit 21A. As a result, the DC current supplied from the high-power battery 1 is converted to an AC current and output to the drive motor, and the regenerative current from the drive motor is converted to a DC current and supplied to the high-power line. As described above, the drive circuit 21C operates using power from the main power supply circuit 20.

[0028] In the normal state, as shown in FIG. 1, the switch 30A of the first power supply circuit 30 is on and the switch 30B is off, and the switch 40A of the second power supply circuit 40 is on and the switch 40B is off. Since the switches 30B and 40B are off, there is no conduction between the secondary power supply circuit 10 and the three-phase short circuit 22 and the overvoltage detection circuit 23. In the normal state, the secondary power supply circuit 10 is not activated. Meanwhile, since the switch 40A is on, power is supplied from the primary power supply circuit 20 to the overvoltage detection circuit 23, which operates the overvoltage detection circuit 23. In the normal state, the switch 30A is on, but the switch 22B of the three-phase short circuit 22 is off. Therefore, in the normal state, no power is supplied from the first power supply circuit 30 to the three-phase short circuit 22.

[0029] As described above, in the normal state, the power for driving the control means (the control circuit 21, the overvoltage detection circuit 23) is mainly supplied from the main power supply circuit 20.

[0030] FIG. 2 is a circuit diagram showing the power conversion device 100 in an overvoltage state.

[0031] In an overvoltage state in which an overvoltage is detected by the overvoltage detection circuit 23, the slave power supply circuit 10 is started up by an overvoltage detection signal from the overvoltage detection circuit 23, and the switch 22A of the three-phase short circuit 22 is switched off and the switches 22B and 22C are switched on. In addition, the overvoltage detection signal from the overvoltage detection circuit 23 controls the switches 30A and 30B of the first power supply circuit 30 and the switches 40A and 40B of the second power supply circuit 40 to be all on.

[0032] As described above, in the overvoltage state, the switch 22A on the lines 221, 222 connecting the control circuit 21 (drive circuit 21C) and the inverter 12 is switched off, so that the control circuit 21 does not supply power for controlling the inverter 12. Meanwhile, the switches 30A and 30B of the first power supply circuit 30 and the switch 22B of the three-phase short circuit 22 are all controlled to be on, so that the semiconductor element 12A of the upper arm is supplied with power for control from either the main power supply circuit 20 or the secondary power supply circuit 10, whichever has a higher output voltage. At this time, the semiconductor elements 12A of the upper arm are all controlled to be on (conductive state). In addition, the switch 22C of the three-phase short circuit 22 is controlled to be on, so that the gates of the semiconductor elements 12B of the lower arm are connected to ground, and the semiconductor elements 12B of the lower arm are all off (non-conductive state). That is, in an overvoltage state, all of the upper arm semiconductor elements 12A are turned on and all of the lower arm semiconductor elements 12B are turned off, so that the internal circuit of the inverter 12 (upper arm semiconductor elements 12A) is in a three-phase short-circuited state. As a result, a direct current caused by a regenerative current is not supplied to the storage circuit 11, and the overvoltage is suppressed. Thus, in an overvoltage state, the three-phase short-circuit circuit 22 functions as a control means, and the three-phase short-circuit circuit 22 executes three-phase short-circuit control using the semiconductor elements 12A and 12B of the inverter 12.

[0033] In addition, in an overvoltage state, both switches 40A and 40B of the second power supply circuit 40 are controlled to be on, so that power to drive the overvoltage detection circuit 23 is supplied from either the main power supply circuit 20 or the secondary power supply circuit 10, whichever has the higher output voltage.

[0034] In this embodiment, the output voltage of the main power supply circuit 20 is set to be higher than the output voltage of the secondary power supply circuit 10. Therefore, even in an overvoltage state, power is supplied from the main power supply circuit 20 to the three-phase short circuit 22 and the overvoltage detection circuit 23. However, this is not necessarily limited to this, and in an overvoltage state, the output voltage of the secondary power supply circuit 10 may be set higher than the output voltage of the main power supply circuit 20 so that power is supplied from the secondary power supply circuit 10 to the three-phase short circuit 22 and the overvoltage detection circuit 23. Also, the output voltages of the main power supply circuit 20 and the secondary power supply circuit 10 may be set to be equal voltages so that power is supplied from both the main power supply circuit 20 and the secondary power supply circuit 10 in an overvoltage state.

[0035] As described above, in a normal state, the drive circuit 21C (control circuit 21) and the overvoltage detection circuit 23 serving as control means operate with power from the main power supply circuit 20. On the other hand, in an overvoltage state, power is supplied from either the main power supply circuit 20 or the secondary power supply circuit 10, whichever has a higher output voltage, to the three-phase short circuit circuit 21C (control circuit 21) and the overvoltage detection circuit 23 serving as control means, and the three-phase short circuit control is executed by the three-phase short circuit circuit 22.

[0036] Incidentally, in a power conversion device equipped with a control means that operates using power supplied from a low-voltage power source (low-voltage battery), if there is only one power supply circuit, there is a risk that the induced voltage cannot be controlled if the power supply circuit fails.

[0037] In contrast, the power conversion device 100 of this embodiment includes a main power supply circuit 20 connected to the low power battery 2, and a secondary power supply circuit 10 connected to the high power battery 1. Also, the power conversion device 100 includes power supply circuits 30, 40 configured to be able to supply power not only from the main power supply circuit 20 but also from the secondary power supply circuit 10 to the three-phase short circuit 22 and the overvoltage detection circuit 23. Therefore, even if the main power supply circuit 20 (power supply circuit) fails, power can be supplied from the secondary power supply circuit 10 to the three-phase short circuit 22 and the overvoltage detection circuit 23, and three-phase short circuit control can be performed using power from the secondary power supply circuit 10. That is, even if the main power supply circuit (power supply circuit) fails, the induced voltage can be controlled.

[0038] Furthermore, when the power supply circuit is connected to a high-power battery so that power can be supplied to the control means even when the low-power power supply (low-power battery) is abnormal, and power is supplied from the high-power battery to the low-power line of the control system, there is a risk that the power supply circuit will generate large noise. For this reason, it is necessary to provide a filter circuit or the like for suppressing noise, which increases the circuit size. In contrast, the power conversion device 100 of this embodiment enables power supply from the secondary power supply circuit 10 to the low-power line only in an abnormal state such as an overvoltage state. In addition, in a normal state, the secondary power supply circuit 10 and the low-power line are disconnected, and power is supplied to the low-power line from the low-power battery 2 and the main power supply circuit 20. Therefore, there is no need to provide a separate circuit for suppressing noise, and an increase in the circuit size can be suppressed.

[0039] In addition, when the power supply circuit is connected to a high-power battery and power is supplied from the power supply circuit to both the high-power line and the low-power line, it is necessary to cover all the power consumption of the power conversion device, and the circuit size increases. In contrast, the power conversion device 100 of the present embodiment includes two power supply circuits 10 and 20, so that one power supply circuit does not need to cover all the power consumption, and the increase in the circuit size can be suppressed.

[0040] The secondary power supply circuit 10 and the power supply circuits 30 and 40 will be described in detail below.

[0041] Fig. 3 is a diagram showing an example of the slave power supply circuit 10. As shown in Fig. 3, the slave power supply circuit 10 of this embodiment is composed of a transformer 10A, a switching element 10B, a rectifier diode 10C, and a smoothing capacitor 10D.

[0042] The transformer 10A has a primary coil connected to a line 101 connected to the high-power battery 1 and to the switching element 10B, and a secondary coil connected to a line 102 connected to the first power supply circuit 30 and the second power supply circuit 40 and to a grounded line 103.

[0043] Switching element 10B is configured, for example, by a transistor (MOSFET) that turns current to transformer 10A on and off, with a first terminal (source) grounded and a second terminal (drain) connected to the primary coil of transformer 10A. When an overvoltage detection signal from overvoltage detection circuit 23 is applied to the gate of switching element 10B, secondary power supply circuit 10 is started, and the overvoltage detection signal controls the on and off of switching element 10B. By controlling the on and off of switching element 10B, the voltage on the primary coil side of transformer 10A is controlled, and the output voltage of secondary power supply circuit 10 is controlled.

[0044] Rectifier diode 10C is provided on line 102 that connects to the secondary coil of transformer 10A, and smoothing capacitor 10D is provided in parallel to transformer 10A between line 102 and line 103. Rectifier diode 10C passes only one-way current on the secondary coil side of transformer 10A, thereby charging smoothing capacitor 10D. Smoothing capacitor 10D charges with the current flowing through rectifier diode 10C, and generates an output voltage (the output voltage of secondary power supply circuit 10) between line 102 and line 103.

[0045] As described above, the slave power supply circuit 10 is started when an overvoltage detection signal is applied, and the output voltage is controlled by turning on and off the switching element 10B in response to the overvoltage detection signal. In this way, the slave power supply circuit 10 is started only when an overvoltage is detected, and is stopped in the normal state, so that unnecessary power consumption can be suppressed. In addition, the generation of noise in the normal state can be suppressed.

[0046] FIG. 4 is a diagram illustrating an example of the first power supply circuit 30. As shown in FIG.

[0047] As shown in FIG. 4, the first power supply circuit 30 of the present embodiment is configured by switching elements 301A, 302A, 301B, and 302B, which are transistors (MOSFETs).

[0048] The switching elements 301A and 302A are the switch 30A of the first power supply circuit 30, and are provided in series between the line 301 connected to the output part of the main power supply circuit 20 and the output part of the first power supply circuit 30. As described above, the output part of the first power supply circuit 30 is connected to the line 223 including the switch 22B of the three-phase short circuit 22.

[0049] A first terminal (source) of the switching element 301A is connected to a second terminal (drain) of the switching element 302A, and the second terminal (drain) is connected to a line 301 connected to an output part of the main power supply circuit 20. A first terminal (source) of the switching element 302A is connected to an output part (line 223) of the power supply circuit 30, and a second terminal (drain) of the switching element 302A is connected to the first terminal (source) of the switching element 301A. The switching elements 301A and 302A are turned on in a normal state. Also, in an overvoltage state, they are controlled to be on even when an overvoltage detection signal is applied from the overvoltage detection circuit 23. That is, the switch 30A on the main power supply circuit 20 side of the first power supply circuit 30 is always turned on.

[0050] The switching elements 301B and 302B are the switches 30B of the first power supply circuit 30, and are provided in series between a line 302 connected to the output of the secondary power supply circuit 10 and the output of the first power supply circuit 30. A first terminal (source) of the switching element 301B is connected to a second terminal (drain) of the switching element 302B, and the second terminal (drain) is connected to the line 302 connected to the output of the main power supply circuit 20. A first terminal (source) of the switching element 302B is connected to the output (line 223) of the first power supply circuit 30, and a second terminal (drain) of the switching element 302B is connected to the first terminal (source) of the switching element 301B. The switching elements 301B and 302B are turned off in a normal state. When an overvoltage detection signal is applied from the overvoltage detection circuit 23 to the gates of the switching elements 301B and 302B, the switching elements 301B and 302B are switched on. That is, the switch 30B of the first power supply circuit 30 on the side of the secondary power supply circuit 10 is controlled to be off in a normal state and to be on in an overvoltage state.

[0051] As described above, since the first power supply circuit 30 is configured with the transistor switching elements 301A, 302A, 301B, and 302B, it is possible to freely connect and disconnect the main power supply circuit 20 and the sub power supply circuit 10 to and from the three-phase short circuit 22. As will be described later, it is also possible to keep the sub power supply circuit 10 activated even in the normal state, but even in such a case, by configuring the first power supply circuit 30 with switching elements, it is possible to make only the main power supply circuit 20 conductive in the normal state, regardless of the magnitude of the output voltage of the main power supply circuit 20 and the output voltage of the sub power supply circuit 10.

[0052] Although the power supply circuit has been described using the first power supply circuit 30 here, the first power supply circuit 30 and the second power supply circuit 40 can have the same circuit configuration, but only have different output destinations. That is, the switch 40A and the switch 40B of the second power supply circuit 40 are also composed of two switching elements, and the switch 40A on the main power supply circuit 20 side is always on, and the switch 40B on the secondary power supply circuit 10 side is controlled to be off in a normal state and to be on in an overvoltage state. As described above, the output section of the second power supply circuit 40 is connected to the overvoltage detection circuit 23.

[0053] According to the power conversion device 100 of the first embodiment described above, the following effects can be obtained.

[0054] The power conversion device 100 includes a main power supply circuit 20 connected to a low-power battery 2, and a secondary power supply circuit 10 connected to a high-power battery 1. The power conversion device 100 also includes power supply circuits 30, 40 configured to be able to supply power not only from the main power supply circuit 20 but also from the secondary power supply circuit 10 to a three-phase short circuit 22 and an overvoltage detection circuit 23. As a result, even if the main power supply circuit 20 fails, it is possible to execute three-phase short-circuit control using power from the secondary power supply circuit 10. That is, even if the main power supply circuit 20 fails, it is possible to control the induced voltage.

[0055] In addition, since it is equipped with a main power supply circuit 20 connected to the low-power battery 2 and a secondary power supply circuit 10 connected to the high-power battery 1, there is no need for a single power supply circuit to cover all power consumption, and an increase in circuit size can be suppressed.

[0056] The power conversion device 100 is configured such that the power supply circuits 30, 40 can connect or disconnect the main power supply circuit 20 and the secondary power supply circuit 10 to or from the three-phase short circuit 22 and the overvoltage detection circuit 23 by switching. In a normal state, the main power supply circuit 20 and the overvoltage detection circuit 23 are connected, power is supplied from the main power supply circuit 20 to the overvoltage detection circuit 23, and the main power supply circuit 20 and the three-phase short circuit 22, and the secondary power supply circuit 10 and the three-phase short circuit 22 and the overvoltage detection circuit 23 are disconnected. On the other hand, when the overvoltage detection circuit 23 detects an overvoltage, both the main power supply circuit 20 and the secondary power supply circuit 10 are connected to the three-phase short circuit 22 and the overvoltage detection circuit 23, and power is supplied from one of the main power supply circuit and the secondary power supply circuit to the three-phase short circuit and the overvoltage detection circuit. In this way, only in an abnormal state such as an overvoltage state, the secondary power supply circuit 10 connected to the high-power battery 1 is connected to the three-phase short circuit 22 on the low-power line and the overvoltage detection circuit 23, and in a normal state, the connection between the secondary power supply circuit 10 and the low-power line is cut off. Therefore, there is no need to provide a separate circuit for suppressing noise, and an increase in the circuit size can be suppressed.

[0057] In the power conversion device 100, the power supply circuits 30, 40 are composed of transistor switching elements. The main power supply circuit 20 and the secondary power supply circuit 10 can be freely connected and disconnected from the three-phase short circuit 22 and the overvoltage detection circuit 23. Therefore, even when the secondary power supply circuit 10 is activated in a normal state, only the switch on the main power supply circuit 20 side can be made conductive, regardless of the magnitude of the output voltage of the main power supply circuit 20 and the output voltage of the secondary power supply circuit 10. In other words, the generation of noise in the secondary power supply circuit 10 in a normal state can be suppressed.

[0058] In the power conversion device 100, the secondary power supply circuit 10 includes a transformer 10A and a switching element 10B connected to a primary coil of the transformer 10A, and the output voltage of the secondary power supply circuit 10 is controlled by turning on and off the switching element 10B in response to an overvoltage detection signal. In this way, the output voltage of the secondary power supply circuit 10 is controlled by the switching element based on the overvoltage detection signal, so that unnecessary power consumption in the normal state can be suppressed.

[0059] In the power conversion device 100, the secondary power supply circuit 10 is driven when the overvoltage detection circuit 23 detects an overvoltage. In this way, the secondary power supply circuit 10 is driven only when an overvoltage is detected and is stopped in the normal state, so that unnecessary power consumption can be suppressed. In addition, the generation of noise in the normal state can be suppressed.

[0060] In this embodiment, the slave power supply circuit 10 is driven only when an overvoltage is detected and is stopped in the normal state, but this is not necessarily limited to the above. That is, the slave power supply circuit 10 may be driven in the normal state as well. In this case, it is preferable to drive the slave power supply circuit 10 in the normal state as well, and increase the switching frequency of the switching element 10B when the overvoltage detection circuit 23 detects an overvoltage. This improves the responsiveness of the slave power supply circuit 10.

[0061] 5, the secondary power supply circuit 10 may further include a Zener diode 10E that is connected to the secondary coil of the transformer 10A and generates a constant voltage, and a resistor 10F on a line that connects a line 101 that is connected to the high-power battery 1 with a line 102 that is connected to the first power supply circuit 30 and the second power supply circuit 40. In this case, when the overvoltage detection circuit 23 detects an overvoltage, a voltage obtained by applying a constant voltage generated by the Zener diode 10E to a voltage converted by turning on and off the switching element 10B is output from the secondary power supply circuit 10. In addition, since the Zener diode 10E generates a constant voltage even when the switching element 10B is stopped in a normal state, the smoothing capacitor 10D is charged even in the normal state. Therefore, noise of the secondary power supply circuit 10 is suppressed, and the responsiveness of the secondary power supply circuit 10 when an overvoltage is detected is improved.

[0062] In addition, in this embodiment, the power supply circuits 30, 40 are configured by two switching elements on a line connecting to the output part of the main power supply circuit 20 and two switching elements on a line connecting to the output part of the secondary power supply circuit 10, but this is not necessarily limited to this. Any other configuration may be used as long as it is possible to connect and disconnect the main power supply circuit 20 and the secondary power supply circuit 10 to and from the three-phase short circuit 22 and the overvoltage detection circuit 23.

[0063] The power supply circuits 30 and 40 may be configured without a switching element. For example, as shown in FIG. 6, the first power supply circuit 30 may be configured such that a diode 30C on a line 301 connected to the output part of the main power supply circuit 20 and a diode 30D on a line 302 connected to the output part of the sub power supply circuit 10 are connected in parallel, and the output parts of these diodes 30C and 30D are connected to the three-phase short circuit 22 (line 223). Similarly, the second power supply circuit 40 may be configured such that a diode on a line 301 connected to the output part of the main power supply circuit 20 and a diode on a line 302 connected to the output part of the sub power supply circuit 10 are connected in parallel, and the output parts of these diodes are connected to the overvoltage detection circuit 23. In these cases, the output voltage of the sub power supply circuit 10 is controlled to be lower than the output voltage of the main power supply circuit 20 in the normal state. As a result, the power supply circuits 30 and 40 are capable of conducting only power from the main power supply circuit 20 in the normal state, and power is supplied to the overvoltage detection circuit 23 only from the main power supply circuit 20 in the normal state. In addition, since switch 22B of three-phase short circuit 22 is off in the normal state, power is not supplied from first power supply circuit 30 to three-phase short circuit 22 even in the normal state. Even in the circuit shown in Fig. 6, if main power supply circuit 20 fails, power can be supplied from secondary power supply circuit 10 to three-phase short circuit 22 and overvoltage detection circuit 23. Also in the circuit shown in Fig. 6, power is not supplied from secondary power supply circuit 10 to the low-voltage line (control circuit 21, three-phase short circuit 22, overvoltage detection circuit 23) in the normal state, so that generation of noise from secondary power supply circuit 10 in the normal state can be suppressed.

[0064] 7, the first power supply circuit 30 may be a circuit in which a line 301 connected to the output part of the main power supply circuit 20 and a line 302 connected to the output part of the sub power supply circuit 10 are connected in parallel to the line 223 of the three-phase short circuit 22. Similarly, the second power supply circuit 40 may be a circuit in which a line 301 connected to the output part of the main power supply circuit 20 and a line 302 connected to the output part of the sub power supply circuit 10 are connected in parallel to the overvoltage detection circuit 23. In these cases, in the normal state, the output voltage of the sub power supply circuit 10 is controlled to be lower than the output voltage of the main power supply circuit 20. As a result, the power supply circuits 30 and 40 can conduct only power from the main power supply circuit 20 side in the normal state, and power is supplied to the overvoltage detection circuit 23 only from the main power supply circuit 20 in the normal state. Note that in the normal state, the switch 22B of the three-phase short circuit 22 is turned off, so that power is not supplied from the first power supply circuit 30 to the three-phase short circuit 22 even in the normal state. 7, in the event of a failure of the main power supply circuit 20, it is possible to supply power from the secondary power supply circuit 10 to the three-phase short circuit 22 and the overvoltage detection circuit 23. Also, in the circuit shown in Fig. 7, since power is not supplied from the secondary power supply circuit 10 to the low-voltage line (the control circuit 21, the three-phase short circuit 22, and the overvoltage detection circuit 23) in the normal state, it is possible to suppress the generation of noise from the secondary power supply circuit 10 in the normal state.

[0065] In the present embodiment, the first power supply circuit 30 that supplies power to the three-phase short circuit 22 and the second power supply circuit 40 that supplies power to the overvoltage detection circuit 23 are separate circuits, but the first power supply circuit 30 and the second power supply circuit 40 may be combined into a single power supply circuit. In this case, the output section of the power supply circuit is connected to the three-phase short circuit 22 and the overvoltage detection circuit 23.

[0066] In addition, in the present embodiment, all of the semiconductor elements 12A in the upper arm are turned on and all of the semiconductor elements 12B in the lower arm are turned off in an overvoltage state, but this is not limited as long as three-phase short circuit control can be executed. That is, the circuit may be configured so that all of the semiconductor elements 12A in the upper arm are turned off and all of the semiconductor elements 12B in the lower arm are turned on in an overvoltage state.

[0067] Second embodiment A power conversion device 100 according to the second embodiment will be described with reference to Fig. 8 and Fig. 9. Elements similar to those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted.

[0068] 8 is a schematic configuration diagram of a power conversion device 100 of the second embodiment. The second embodiment differs from the first embodiment in that it includes a second signal transmission circuit 211B, a relay 50, and a control circuit 21 executes slave power supply circuit drive control and / or relay cut control using a slave power supply circuit drive signal in a predetermined case.

[0069] As shown in FIG. 8, the power conversion device 100 of this embodiment includes a relay 50 interposed between the high-power battery 1 and the power storage circuit 11.

[0070] In the power conversion device 100 of this embodiment, the signal generating circuit 21A of the control circuit 21 generates a slave power supply circuit start signal in a predetermined case, such as when the motor rotation speed exceeds a reference rotation speed, and outputs the signal as a control signal to the second signal transmission circuit 211B (slave power supply circuit drive control by slave power supply circuit drive signal). Furthermore, when the signal generating circuit 21A of the control circuit 21 receives a relay cut signal from a vehicle controller (not shown) that is a higher-level device, it outputs the relay cut signal to the second signal transmission circuit 211B and the relay 50. The second signal transmission circuit 211B is configured separately from the signal transmission circuit 21B that receives the PWM signal. The second signal transmission circuit 211B outputs the slave power supply circuit start signal received from the signal generating circuit 21A to the slave power supply circuit 10, and outputs the relay cut signal to the slave power supply circuit 10, the three-phase short circuit 22, the first power supply circuit 30, and the second power supply circuit 40. The slave power supply circuit 10 is started when a slave power supply circuit start signal or a relay cut signal is input, and the switches 30A, 30B, 40A, and 40B of the first power supply circuit 30 and the second power supply circuit 40 are switched on and off based on the relay cut signal. The relay 50 is switched off when a relay cut signal is input from the signal generating circuit 21A.

[0071] 8 and 9, the switch control of power conversion device 100 in the slave power supply circuit drive control and relay cut control by the slave power supply circuit drive signal will be described below. Note that the following description is based on the premise that overvoltage detection circuit 23 does not detect an overvoltage.

[0072] FIG. 9 is a circuit diagram showing the power conversion device 100 when relay cut control is being executed.

[0073] When relay cut control is not being executed, as shown in Fig. 8, the relay 50 is on, the switch 30A of the first power supply circuit 30 is on, the switch 30B is off, and the switch 40A of the second power supply circuit 40 is on and the switch 40B is off. Since no overvoltage is detected, the switch 22A of the three-phase short circuit 22 is on, and the switches 22B and 22C are off. Therefore, when relay cut control is not being executed, power is supplied from the main power supply circuit 20 to the drive circuit 21C and the overvoltage detection circuit 23.

[0074] The signal generating circuit 21A of the control circuit 21 generates a slave power supply circuit start signal in a predetermined case, and outputs the signal as a control signal to the second signal transmission circuit 211B. When the second signal transmission circuit 211B receives the slave power supply circuit start signal, it transmits the signal to the slave power supply circuit 10 to drive the slave power supply circuit 10 (slave power supply circuit drive control by the slave power supply circuit drive signal). The predetermined case for generating the slave power supply circuit start signal is, as described above, when the motor rotation speed exceeds the reference rotation speed. As described above, the reference rotation speed can be set to a motor rotation speed at which, for example, if the motor rotation speed continues to increase, the voltage of the high-power line may exceed the withstand voltage of each component on the high-power line due to a voltage increase caused by the motor induced voltage. In such a case, there is a high possibility that overvoltage detection or three-phase short circuit control by relay cut control described later will be performed, so by driving the slave power supply circuit in advance, the responsiveness of the slave power supply circuit 10 can be improved.

[0075] Furthermore, when the signal generating circuit 21A of the control circuit 21 receives a relay cut signal from the vehicle controller, it starts relay cut control. The relay cut signal is generated when an overvoltage is expected or when the vehicle must be forcibly stopped. When the relay cut control is executed, as shown in FIG. 9, the relay 50 is turned off by the relay cut signal from the signal generating circuit 21A. This cuts off the power supply from the high-power battery 1 to the high-power line. Furthermore, when the slave power supply circuit 10 is not driven, the slave power supply circuit 10 is driven when the relay cut signal from the second signal transmission circuit 211B is input to the slave power supply circuit 10. When the slave power supply circuit 10 has already been driven by the slave power supply circuit start signal, the slave power supply circuit 10 continues to operate as is. Furthermore, by a relay cut signal from the second signal transmission circuit 211B, the switch 30A of the first power supply circuit 30 and the switch 40A of the second power supply circuit 40 are kept on, the switch 30B of the first power supply circuit 30 and the switch 40B of the second power supply circuit 40 are switched on, the switch 22A of the three-phase short circuit 22 is switched off, and the switches 22B and 22C are switched on. As a result, the overvoltage detection circuit 23 and the three-phase short circuit 22 are placed in a state in which power can be supplied from both the main power supply circuit 20 and the secondary power supply circuit 10, and power is supplied to the overvoltage detection circuit 23 from either the main power supply circuit 20 or the secondary power supply circuit 10, whichever has a higher output voltage. Furthermore, power is supplied from the first power supply circuit 30 to the three-phase short circuit 22, and the semiconductor elements 12A of the upper arm are controlled to be both on (conductive). That is, three-phase short circuit control is executed in which all of the semiconductor elements 12A in the upper arm are turned on and all of the semiconductor elements 12B in the lower arm are turned off.

[0076] In this way, when the relay cut control is executed, the three-phase short circuit control is executed, and an overvoltage state is prevented. Also, when the relay cut control is executed, the DC current from the high-power battery 1 is not supplied to the storage circuit 11, and power is supplied from the storage circuit 11 to the inverter 12 and the secondary power supply circuit 10. This consumes the power of the storage circuit 11, and prevents an overvoltage state from occurring.

[0077] As described above, in the power conversion device 100 of the second embodiment, the control circuit 21 outputs a slave power supply circuit start signal in a predetermined case to drive the slave power supply circuit 10, thereby executing slave power supply circuit drive control by a slave power supply circuit drive signal. Also, the power conversion device 100 of the second embodiment includes a relay 50 interposed between the high-power battery 1 and the storage circuit 11, and the control circuit 21 executes relay cut control upon receiving a relay cut signal.

[0078] According to the power conversion device 100 of the second embodiment described above, the following effects can be obtained.

[0079] The power conversion device 100 includes a relay 50 interposed between the high-power battery 1 and the storage circuit 11, and the control circuit 21 executes relay cut control for the relay 50 to cut off DC power from the high-power battery 1 in a predetermined case. When the relay cut control is executed, both the main power supply circuit 20 and the secondary power supply circuit 10 are connected to the three-phase short circuit 22 and the overvoltage detection circuit 23, and power is supplied to the three-phase short circuit 22 and the overvoltage detection circuit 23 from one of the main power supply circuit 20 and the secondary power supply circuit 10. This allows the three-phase short circuit 22 and the overvoltage detection circuit 23 to be driven by power from the secondary power supply circuit 10 even if the main power supply circuit 20 fails. That is, even if the main power supply circuit 20 fails, the three-phase short circuit control and overvoltage detection can be performed, and the induced voltage can be controlled.

[0080] In the power conversion device 100, when the overvoltage detection circuit 23 does not detect an overvoltage and the relay cut control is not being executed, the power supply circuits 30, 40 connect the main power supply circuit 20 to the overvoltage detection circuit 23 and cut off the main power supply circuit 20 to the three-phase short circuit 22, and the sub power supply circuit 10 to the three-phase short circuit 22 and the overvoltage detection circuit 23. On the other hand, when the relay cut control is being executed, the power supply circuits 30, 40 connect both the main power supply circuit 20 and the sub power supply circuit 10 to the three-phase short circuit 22 and the overvoltage detection circuit 23. In this way, only when the relay cut control is being executed, the sub power supply circuit 10 connected to the high-power battery 1 is connected to the three-phase short circuit 22 and the overvoltage detection circuit 23 on the low-power line, and when the relay cut control is not being executed, the connection between the sub power supply circuit 10 and the low-power line is cut off. This makes it possible to suppress the generation of noise in the sub power supply circuit 10 when the relay cut control is not being executed. Therefore, there is no need to provide a separate circuit for suppressing noise, and an increase in the circuit size can be suppressed.

[0081] In power conversion device 100, control circuit 21 drives the slave power supply circuit when the motor rotation speed exceeds a reference rotation speed. In this way, slave power supply circuit 10 is driven in advance when the motor rotates at high speed (when the reference rotation speed is exceeded) when the motor induced voltage increases, thereby improving the responsiveness of slave power supply circuit 10. Furthermore, since slave power supply circuit 10 is not driven when the motor rotation speed is equal to or lower than the reference rotation speed, noise generation in slave power supply circuit 10 can be suppressed. Therefore, there is no need to provide a separate circuit for suppressing noise, and an increase in the circuit size can be suppressed.

[0082] In the power conversion device 100, the slave power supply circuit 10 is driven when the overvoltage detection circuit 23 detects an overvoltage, when the motor rotation speed exceeds the reference rotation speed, or when the control circuit 21 executes relay cut control. In this way, the slave power supply circuit 10 is driven only when an overvoltage is detected, when the motor rotation speed exceeds the reference rotation speed, or when relay cut control is executed, and is stopped in other cases, so that wasteful power consumption can be suppressed. Furthermore, generation of noise from the slave power supply circuit 10 can be suppressed when an overvoltage is not detected, when the motor rotation speed is equal to or lower than the reference rotation speed, and when relay cut control is not executed.

[0083] In this embodiment, the configuration is such that both slave power circuit drive control and relay cut control are performed using the slave power circuit drive signal, but this is not necessarily limited to this, and the configuration may be such that only one of slave power circuit drive control and relay cut control is performed using the slave power circuit drive signal.

[0084] In the present embodiment, the slave power supply circuit 10 is driven only when an overvoltage is detected, when the motor rotation speed exceeds the reference rotation speed, or when relay cut control is executed, and is stopped in other cases, but this is not necessarily limited to the above. That is, the slave power supply circuit 10 may be driven even when an overvoltage is not detected, the motor rotation speed is equal to or lower than the reference rotation speed, and relay cut control is not executed. In this case, it is preferable to first drive the slave power supply circuit 10, and then increase the switching frequency of the switching element 10B of the slave power supply circuit 10 when relay cut control is executed, when the motor rotation speed exceeds the reference rotation speed, or when the overvoltage detection circuit 23 detects an overvoltage. This improves the responsiveness of the slave power supply circuit 10.

[0085] Also in this embodiment, as in the first embodiment, the slave power supply circuit 10 may be configured to include a Zener diode 10E shown in Fig. 5. In this case, when relay cut control is executed, when the motor rotation speed exceeds the reference rotation speed, or when overvoltage detection circuit 23 detects an overvoltage, a voltage obtained by converting switching element 10B by turning it on and off and then applying a constant voltage generated by Zener diode 10E to the voltage is output from slave power supply circuit 10.

[0086] Also in this embodiment, the power supply circuits 30, 40 may have any configuration as long as they can connect and disconnect the main power supply circuit 20 and the sub power supply circuit 10 to and from the three-phase short circuit 22 and the overvoltage detection circuit 23. For example, they may be a circuit in which diodes are connected in parallel as shown in Fig. 6, or a circuit in which the output part of the main power supply circuit 20 and the output part of the sub power supply circuit 10 are connected in parallel to the output part of the power supply circuits 30, 40 as shown in Fig. 7. In these cases, when relay cut control is not being executed and an overvoltage is not detected, the output voltage of the sub power supply circuit 10 is controlled to be lower than the output voltage of the main power supply circuit 20.

[0087] Also in this embodiment, when relay cut control is executed, the output voltage of the main power supply circuit 20 is set to be higher than the output voltage of the secondary power supply circuit 10 so that power is supplied from the main power supply circuit 20 to the three-phase short circuit 22 and the overvoltage detection circuit 23, but this is not necessarily limited to this. For example, when relay cut control is executed, the output voltage of the main power supply circuit 20 may be set lower than the output voltage of the secondary power supply circuit 10. That is, when relay cut control is executed, it is sufficient that the configuration is such that power is supplied from one of the main power supply circuit 20 and the secondary power supply circuit 10 to the overvoltage detection circuit 23. Even in such a case, when the main power supply circuit 20 fails, power can be supplied from the secondary power supply circuit 10 to the three-phase short circuit 22 and the overvoltage detection circuit 23. That is, even when the main power supply circuit 20 fails, the induced voltage can be controlled.

[0088] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments.

[0089] Although the above-described embodiments have been described as separate embodiments, they may be combined as appropriate. [Explanation of symbols]

[0090] 1, high-power battery, 2, low-power battery, 10, secondary power supply circuit, 11, storage circuit, 12, inverter, 12A, upper arm semiconductor element, 12B, lower arm semiconductor element, 20, main power supply circuit, 21, control circuit, 22, three-phase short circuit, 23, overvoltage right circuit, 30, first power supply circuit (power supply circuit), 40, second power supply circuit (power supply circuit), 50, relay, 100, power conversion device

Claims

1. A high-power battery, A low-power battery; a storage circuit that stores and smoothes the DC power supplied from the high-power battery; a plurality of semiconductor elements that convert DC power supplied from the high-power battery and the power storage circuit into AC power for driving a motor; A control circuit for controlling an operation of the semiconductor device; an overvoltage detection circuit that detects an overvoltage in the storage circuit when the voltage of the storage circuit exceeds a reference voltage; a three-phase short circuit that executes three-phase short circuit control using the semiconductor element when the overvoltage detection circuit detects an overvoltage; a main power supply circuit connected to the low-power battery; a secondary power supply circuit connected to the high-power battery; a power supply circuit configured to be able to supply power to the three-phase short circuit and the overvoltage detection circuit not only from the main power supply circuit but also from the sub power supply circuit; Equipped with the plurality of semiconductor elements include a plurality of upper arm semiconductor elements connected to a positive electrode side of the high power battery and a plurality of lower arm semiconductor elements connected to a negative electrode side of the high power battery, In a normal state where an overvoltage is not detected, the semiconductor element is controlled by driving the control circuit based on the power from the main power supply circuit, and the overvoltage detection circuit is driven based on the power from the main power supply circuit; When the overvoltage detection circuit detects an overvoltage, the three-phase short circuit turns on all of either the upper arms or the lower arms of the semiconductor elements based on power from one of the main power supply circuit and the secondary power supply circuit, and turns off all of the other of the upper arms and the lower arms of the semiconductor elements, and the overvoltage detection circuit is driven based on power from one of the main power supply circuit and the secondary power supply circuit. Power conversion equipment.

2. The power conversion device according to claim 1, A relay is further provided between the high-power battery and the storage circuit. The control circuit executes relay cut control for cutting off DC power from the high-power battery in a predetermined case, When the normal state is established and the relay cut control is not being executed, the semiconductor element is controlled by driving the control circuit based on the power from the main power supply circuit, and the overvoltage detection circuit is driven based on the power from the main power supply circuit, When the relay cut control is executed, the three-phase short circuit turns on all of either the upper arms or the lower arms of the semiconductor elements based on power from one of the main power supply circuit or the secondary power supply circuit, and turns off all of the other of the upper arms and the lower arms of the semiconductor elements, and the overvoltage detection circuit is driven based on power from one of the main power supply circuit or the secondary power supply circuit. Power conversion equipment.

3. The power conversion device according to claim 1 or 2, the power supply circuit is configured to be able to connect or disconnect the main power supply circuit and the sub power supply circuit to or from the three-phase short circuit and the overvoltage detection circuit by switching, and in a normal state, connects the main power supply circuit to the overvoltage detection circuit and supplies power from the main power supply circuit to the overvoltage detection circuit, and disconnects the main power supply circuit from the three-phase short circuit, and the sub power supply circuit from the three-phase short circuit and the overvoltage detection circuit, and when the overvoltage detection circuit detects an overvoltage, connects both the main power supply circuit and the sub power supply circuit to the three-phase short circuit and the overvoltage detection circuit, and supplies power from one of the main power supply circuit and the sub power supply circuit to the three-phase short circuit and the overvoltage detection circuit. Power conversion equipment.

4. The power conversion device according to claim 2, the power supply circuit is configured to be able to connect or disconnect the main power supply circuit and the sub power supply circuit to or from the three-phase short circuit and the overvoltage detection circuit by switching, and when the overvoltage detection circuit does not detect an overvoltage and relay cut control is not being executed, connects the main power supply circuit to the overvoltage detection circuit and supplies power from the main power supply circuit to the overvoltage detection circuit, and disconnects the main power supply circuit from the three-phase short circuit, and the sub power supply circuit from the three-phase short circuit and the overvoltage detection circuit, and when an overvoltage is detected or relay cut control is being executed, connects both the main power supply circuit and the sub power supply circuit to the three-phase short circuit and the overvoltage detection circuit, and supplies power from one of the main power supply circuit and the sub power supply circuit to the three-phase short circuit and the overvoltage detection circuit. Power conversion equipment.

5. 5. The power conversion device according to claim 1, The power supply circuit is configured with a switching element using a transistor. Power conversion equipment.

6. The power conversion device according to claim 1 or 2, The power supply circuit includes a diode connected to the main power supply circuit and a diode connected to the sub power supply circuit, the diodes being connected in parallel, and outputs of the diodes being connected to the three-phase short circuit and the overvoltage detection circuit; In a normal state, the output voltage of the secondary power supply circuit is lower than the output voltage of the main power supply circuit. Power conversion equipment.

7. The power conversion device according to claim 1 or 2, the power supply circuit is configured such that an output section of the main power supply circuit and an output section of the sub power supply circuit are connected in parallel to the three-phase short circuit and the overvoltage detection circuit; In a normal state, the output voltage of the secondary power supply circuit is lower than the output voltage of the main power supply circuit. Power conversion equipment.

8. 8. The power conversion device according to claim 1, the secondary power supply circuit includes a transformer and a switching element connected to a primary coil of the transformer; The output voltage of the secondary power supply circuit is controlled by turning on and off the switching element. Power conversion equipment.

9. The power conversion device according to claim 8, the secondary power supply circuit further includes a Zener diode connected to the secondary coil of the transformer and generating a constant voltage; The output voltage of the secondary power supply circuit is a voltage obtained by applying a constant voltage generated by the Zener diode to a voltage converted by turning on and off the switching element. Power conversion equipment.

10. 10. The power conversion device according to claim 1, the slave power supply circuit is driven when the motor rotation speed exceeds a reference rotation speed; Power conversion equipment.

11. 10. The power conversion device according to claim 1, the secondary power supply circuit is driven when the overvoltage detection circuit detects an overvoltage. Power conversion equipment.

12. 10. The power conversion device according to claim 1, A relay is further provided between the high-power battery and the storage circuit. The control circuit executes relay cut control for cutting off DC power from the high-power battery in a predetermined case, the secondary power supply circuit is driven when the overvoltage detection circuit detects an overvoltage, when the motor rotation speed exceeds a reference rotation speed, or when the control circuit executes relay cut control. Power conversion equipment.

13. The power conversion device according to claim 9 or 10, the secondary power supply circuit increases a switching frequency when the overvoltage detection circuit detects an overvoltage. Power conversion equipment.

14. The power conversion device according to claim 9 or 10, the secondary power supply circuit increases a switching frequency when the overvoltage detection circuit detects an overvoltage or when the motor rotation speed exceeds a reference rotation speed. Power conversion equipment.

15. The power conversion device according to claim 9 or 10, A relay is further provided between the high-power battery and the storage circuit. The control circuit executes relay cut control for cutting off DC power from the high-power battery in a predetermined case, the slave power supply circuit increases a switching frequency when the overvoltage detection circuit detects an overvoltage, when the motor rotation speed exceeds a reference rotation speed, or when the control circuit executes relay cut control. Power conversion equipment.

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