Power conversion device

Abstract

A power conversion device (1000) is provided with: switching elements (411, 421) in which upper and lower arms are connected in series; a gate drive circuit (900) that drives the switching element; a controller (910) that operates by a predetermined low voltage supplied from a low-voltage power supply (4000) and outputs a drive signal for driving the switching element to the gate drive circuit; a gate power supply circuit (800) that generates a gate drive voltage for operating the gate drive circuit and supplies the generated gate drive voltage to the gate drive circuit; and a backup power supply circuit (700) that controls a current supplied from a high-voltage power supply (2000) to the primary winding of the insulating transformer, generates a backup voltage in place of the low voltage, and supplies the generated backup voltage to the controller, the backup power supply circuit being activated by the activation voltage output from the gate power supply circuit.

Description

Technical Field

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

[0002] A power conversion device that converts DC power into AC power has a plurality of phases of upper and lower arm series circuits, which are composed of a switching element of an upper arm and a switching element of a lower arm connected in series. In addition, the switching element is driven by a drive signal output from a controller via a gate drive circuit. The controller is usually powered by a low-voltage power supply, but in order to compensate for its operation even when the low-voltage power supply is lost, a backup power supply circuit is provided. The power of the backup power supply circuit is supplied from a high-voltage power supply different from the low-voltage power supply. In this case, a start-up circuit is required to reduce the voltage of the high-voltage power supply to start the backup power supply circuit.

[0003] Patent document 1 discloses an inverter control circuit that turns on a specific switching element even when a low-voltage system power supply is abnormal without adding a dedicated microcomputer. Patent document 2 discloses a device that suppresses the increase in device size and smoothly controls an inverter even when the power supply of the inverter control circuit is lost. Prior art literature Patent Literature

[0004] Patent Document 1: Japanese Patent Application Publication No. 2017-118815 Patent Document 2: Japanese Patent Application Publication No. 2015-159684 Summary of the invention Problem that the invention aims to solve

[0005] The devices described in Patent Documents 1 and 2 do not disclose the case where a start-up circuit for starting a backup power supply circuit is omitted. Technical means of solving problems

[0006] The power conversion device of the present invention comprises: a switching element, whose upper and lower arms are connected in series; a gate drive circuit, which drives the switching element; a controller, which operates using a specified low voltage supplied from a low-voltage power supply, and outputs a drive signal for driving the switching element to the gate drive circuit; a gate power supply circuit, which generates a gate drive voltage for operating the gate drive circuit, and supplies the generated gate drive voltage to the gate drive circuit; and a backup power supply circuit, which controls the current supplied from the high-voltage power supply to the primary winding of the insulation transformer to generate a backup voltage instead of the low voltage, and supplies the generated backup voltage to the controller, and the backup power supply circuit is started by the start-up voltage output from the gate power supply circuit. Effects of the Invention

[0007] According to the present invention, a start-up circuit for starting up the backup power supply circuit can be omitted. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a diagram showing the overall configuration of the power conversion device according to the first embodiment. Figure 2 This is a detailed configuration diagram of the main parts of the power conversion device according to the first embodiment. Figure 3 (A)~ Figure 3 (F) is a timing chart showing the operation of the backup power supply circuit in the first embodiment. Figure 4 It is a diagram showing a wiring pattern of the power conversion device according to the first embodiment. Figure 5 It is a diagram showing a wiring pattern of a power conversion device in a comparative example. Figure 6 It is a diagram showing the overall configuration of a power conversion device according to the second embodiment. Figure 7 This is a detailed configuration diagram of the main parts of the power conversion device according to the second embodiment. Figure 8 (A)~ Figure 8 (G) is a timing chart showing the operations of the backup power supply circuit and the gate power supply circuit in the second embodiment. DETAILED DESCRIPTION

[0009] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. The following description and drawings are examples for illustrating the present invention, and appropriate omissions and simplifications have been made for clarity of the description. The present invention may also be implemented in various other ways. Unless otherwise specified, each constituent element may be singular or plural.

[0010] [First embodiment] Figure 1 It is a diagram showing the overall configuration of the power conversion device 1000 according to the first embodiment. The power conversion device 1000 converts the DC power supplied from the DC high-voltage power source 2000 such as a battery into AC power to drive the motor 3000. The high-voltage power source 2000 supplies DC power between the positive bus P and the negative bus N of the power conversion device 1000 via the contactor 2001. The motor 3000 is, for example, a three-phase induction motor and is used as a driving source for a vehicle. The motor 3000 is provided with an angle sensor 3001 such as a rotary transformer that outputs the rotation angle.

[0011] The power conversion device 1000 includes a capacitor module 100 connected in parallel between a positive bus P and a negative bus N for smoothing a DC current, a voltage detector 200 for detecting a DC voltage between the positive bus P and the negative bus N, and an inverter circuit 400 for performing power conversion. In addition, a DC current detector 300 for detecting a series current flowing through the positive bus P is provided. In addition, the power conversion device 1000 includes an output current detector 500, a backup power supply circuit 700, a gate power supply circuit 800, a gate drive circuit 900, and a controller 910.

[0012] The backup power supply circuit 700, the gate power supply circuit 800, the gate drive circuit 900, and the controller 910 are arranged on the substrate 600. The substrate 600 is divided into a high voltage side 600H and a low voltage side 600L, and the backup power supply circuit 700 and the gate power supply circuit 800 are separated into the high voltage side 600H and the low voltage side 600L by an insulating element 600a such as a transformer. The gate drive circuit 900 is arranged on the high voltage side 600H of the substrate 600, and the controller 910 is arranged on the low voltage side 600L of the substrate 600.

[0013] The inverter circuit 400 includes a power module 410, which constitutes an upper and lower arm series circuit, and the upper and lower arm series circuit is composed of a switching element 411 and a diode 412 that act as an upper arm, and a switching element 421 and a diode 422 that act as a lower arm. In addition, the power module 410 is provided with three phases (U phase, V phase, W phase) corresponding to each phase winding of the motor 3000. That is, the inverter circuit 400 has a three-phase arm, which is formed by connecting the switching element 411 of the upper arm and the switching element 421 of the lower arm in series between the positive bus P and the negative bus N of the DC. Here, the example of three phases is used for explanation, but for example, it can also be a configuration of a power module 410 with multiple phases in accordance with the number of phases of the motor 3000.

[0014] The switching element 411 of the upper arm and the switching element 421 of the lower arm are provided with emitter sense terminals, and the emitter sense terminals are connected to the gate drive circuit 900 in order to detect currents flowing through the switching elements 411 and 421 . The emitter of the switching element 421 of the lower arm is connected to the ground GND3 in the gate drive circuit 900. The emitters of the switching elements 421 of the lower arms of other phases are connected to the grounds GND2 and GND1 in the gate drive circuit 900 in the same manner.

[0015] The drive signal Pw, which is a PWM signal output from the controller 910 , is input to the base terminals of the switching elements 411 and 421 via the gate drive circuit 900 . The switching elements 411 and 421 are, for example, IGBT (Insulated Gate Bipolar Transistor), MOSFET (Metal Oxide Semiconductor Field Effect Transistor), SJ-MOSFET (Super Junction Metal Oxide Semiconductor Field Effect Transistor), or power semiconductor elements made of SiC (Silicon Carbide) or GaN (Gallium Nitride).

[0016] The output current detector 500 detects the AC current output from the connection point of the switching element of the upper arm and the switching element of the lower arm for each phase, and outputs each detection value to the controller 910 .

[0017] A DC low-voltage power source 4000 such as a battery is provided outside the power conversion device 1000. The controller 910 turns on the contactor 4001 in response to the ignition key of the vehicle, and supplies a low voltage from the low-voltage power source 4000 via the diode D1. Then, the drive signal Pw is output to the gate drive circuit 900 based on a torque command from a higher-level controller (not shown), a detection voltage from the voltage detector 200, a DC current detection value from the DC current detector 300, an output current detection value from the output current detector 500, and a rotation angle from the angle sensor 3001.

[0018] The backup power supply circuit 700 controls the current supplied to the primary winding of the isolation transformer according to the power supplied from the high-voltage power supply 2000 via the positive bus P, generates a backup voltage instead of the low voltage supplied from the low-voltage power supply 4000, and supplies it to the controller 910 and the gate power supply circuit 800 via the diode D2. The backup power supply circuit 700 is started by supplying a startup voltage (described later) output from the gate power supply circuit 800 via the reverse current prevention diode D0 and the current limiting resistor R0. The reverse current prevention diode D0 and the current limiting resistor R0 prevent the gate power supply circuit 800 from becoming overloaded and over-voltaged when the voltage of the backup power supply circuit 700 is abnormal. The details of the backup power supply circuit 700 will be described later.

[0019] The gate power supply circuit 800 generates a gate drive voltage for operating the gate drive circuit 900 based on the low voltage from the low voltage power supply 4000 or the backup voltage from the backup power supply circuit 700, and supplies the generated gate drive voltage to the gate drive circuit 900. The gate power supply circuit 800 and the controller 910 are normally supplied with a low voltage from the low voltage power supply 4000, but when the low voltage is not supplied from the low voltage power supply 4000 due to some malfunction, a backup voltage is supplied from the backup power supply circuit 700 instead of the low voltage.

[0020] The gate drive circuit 900 operates using the gate drive voltage supplied from the gate power supply circuit 800, and drives the switching elements 411 and 421 according to the drive signal Pw output from the controller 910. The grounds GND1, GND2, and GND3 in the gate drive circuit 900 are connected to the ground GND0 in the backup power supply circuit 700. The details of the gate drive circuit 900 will be described later.

[0021] Figure 2 It is a detailed configuration diagram of the main parts of the power conversion device 1000 in the first embodiment. In this Figure 2 , a power module 410 of one phase is shown, and the other phases are omitted. In addition, a gate power supply circuit 800 and a gate drive circuit 900 corresponding to the switching element 421 of the lower arm are shown, and a gate power supply circuit 800 and a gate drive circuit 900 corresponding to the switching element 411 of the upper arm are omitted.

[0022] The backup power supply circuit 700 includes a first power supply IC 710 and an isolation transformer TB1. Power is supplied from a high voltage power supply 2000 to one end of a primary winding Nb1 of the isolation transformer TB1 via a positive bus P. At the other end of the primary winding Nb1 of the isolation transformer TB1, a field effect transistor FE1 is connected to a ground GND0 via a resistor R1.

[0023] When the startup voltage Va generated by the gate power supply circuit 800 is supplied to the power supply terminal Vcc of the first power supply IC710 via the reverse current prevention diode D0 and the current limiting resistor R0, the first power supply IC710 is started. Then, the field effect transistor FE1 is switched according to the signal output from the signal terminal SW, and the backup voltage Vb is generated by flyback that operates using the secondary winding Nb2 of the isolation transformer TB1, the diode, and the capacitor. The backup voltage Vb is supplied to the controller 910 and the gate power supply circuit 800. In addition, the backup voltage Vb is also supplied to the gate power supply circuit 800 corresponding to the switching element 411 of the upper arm (not shown).

[0024] In addition, an auxiliary winding Nbc is provided in the isolation transformer TB1, and a feedback voltage Vf is generated using the output voltage from the auxiliary winding Nbc. The feedback voltage Vf is supplied to the power supply terminal Vcc of the first power supply IC710 via a diode, and is input to the feedback terminal FB of the first power supply IC710 after being divided. The first power supply IC710 performs switching control on the field effect transistor FE1 in such a manner that the divided voltage of the feedback voltage Vf input to the feedback terminal FB becomes a predetermined set voltage. Here, since the voltage of the feedback voltage Vf is set to a voltage higher than the start-up voltage Va, the operation of the first power supply IC710 is continued using the power from the feedback voltage Vf after the start-up of the first power supply IC710. Thus, after the first power supply IC710 is started up by the start-up voltage Va generated by the gate power supply circuit 800, it continues its operation by the feedback voltage Vf.

[0025] The gate power supply circuit 800 includes a second power supply IC 810 and an isolation transformer TG1. A low voltage from a low voltage power supply 4000 or a backup voltage Vb from a backup power supply circuit 700 is supplied to a power supply terminal Vcc of the second power supply IC 810. One end of a primary winding Ng1 of the isolation transformer TG1 is connected to the power supply terminal Vcc of the second power supply IC 810, and a field effect transistor FE2 at the other end is connected to a ground GND4 on the low voltage side via a resistor R2.

[0026] The second power supply IC810 performs switching control on the field effect transistor FE2 according to the signal output from the signal terminal SW, and generates a gate drive voltage by flyback using the secondary winding Ng2, diode and capacitor of the isolation transformer TG1. The three gate drive circuits GD1, GD2 and GD3 that drive the switch element 421 of the lower arm are provided with three secondary windings Ng2 of the isolation transformer TG1, and the gate drive voltage is generated respectively. Among them, the gate drive voltage supplied to one gate drive circuit GD3 is supplied to the backup power supply circuit 700 as the starting voltage Va via the reverse current prevention diode D0 and the current limiting resistor R0. As a result, there is no need to set up a separate starting circuit for starting the backup power supply circuit 700. In addition, an auxiliary winding Ngc is provided in the isolation transformer TG1, and the feedback voltage generated using the output voltage from the auxiliary winding Ngc is input to the feedback terminal FB of the second power supply IC810. The second power supply IC810 performs switching control on the field effect transistor FE2 in such a way that the feedback voltage input to the feedback terminal FB becomes a predetermined set voltage.

[0027] The gate drive circuit 900 represents three gate drive circuits GD1, GD2, and GD3 that drive the switch element 421 of the lower arm. In the gate drive circuit GD3, the emitter of the switch element 421 is connected to the ground GND3, the base of the switch element 421 is connected to the terminal of the drive signal Pw, and the emitter readout is connected to the terminal Es. The same is true for the gate drive circuits GD1 and GD2. The drive signal Pw output from the controller 910 is input to the base of the switch element 421, and the switch element 421 is turned on and off for driving. The current flowing through the switch element 421 is read from the emitter via the gate drive circuit GD3 and sent to the controller 910, and the controller 910 controls the overcurrent and the like.

[0028] The gate drive circuits GD1, GD2, and GD3 drive the switch element 421 of the lower arm of each phase, but the grounds GND1, GND2, and GND3 of the gate drive circuits GD1, GD2, and GD3, that is, the emitters of the switch elements 421 of the lower arms of each phase are connected to the ground GND0 in the backup power supply circuit 700. The reason for this will be described later.

[0029] Figure 3 (A)~ Figure 3 (F) is a timing chart showing the operation of the backup power supply circuit 700 in the first embodiment. Figure 3 (A) indicates the low voltage supplied from the low voltage power supply 4000. Figure 3 (B) represents the starting voltage Va supplied from the gate drive circuit GD3, Figure 3 (C) represents a signal output from the signal terminal SW of the first power supply IC710, Figure 3 (D) represents the high voltage supplied by the high voltage power supply 2000, Figure 3 (E) represents the feedback voltage Vf generated by the backup power supply circuit 700, Figure 3 (F) represents the backup voltage Vb generated by the backup power supply circuit 700 .

[0030] Below, refer to Figure 2 The detailed configuration diagram of the main parts of the power conversion device 1000 shown in FIG. If the contactor 4001 is turned on, a low voltage is supplied from the low voltage power supply 4000, such as Figure 3 As shown in (A), the voltage input to the controller 910 and the gate power supply circuit 800 gradually increases from 0V to 12V. 12V is an example of a low voltage. Then, when the voltage reaches the start-up voltage vi of the second power supply IC 810 of the gate power supply circuit 800, as shown in Figure 3 As shown in (B), the gate power supply circuit 800 is started.

[0031] The gate power supply circuit 800 is started, as Figure 3As shown in (B), when the startup voltage Va is greater than the voltage vj at which the first power IC710 of the backup power supply circuit 700 can operate, as shown in Figure 3 As shown in (C), the first power supply IC 710 starts the switching control operation. The 15V starting voltage Va is an example.

[0032] Contactor 2001 is turned on, such as Figure 3 As shown in (D), the high voltage power supply 2000 gradually increases to 400V, for example, to supply power to the backup power supply circuit 700. Figure 3 As shown in (E), a high voltage is applied to the primary winding Nb1 of the isolation transformer TB1 to generate a feedback voltage Vf. The feedback voltage Vf is controlled to a voltage higher than the starting voltage Va, for example, 16V, by switching control of the field effect transistor FE1 by the first power supply IC 710. Figure 3 As shown in (F), the backup power supply circuit 700 generates a backup voltage Vb. The backup voltage Vb is, for example, 8 V. The contactor 4001 is turned on, and after a time Tb, the backup power supply circuit 700 becomes an operating state. Since power is supplied to the backup power supply circuit 700 from the high voltage power supply 2000, even if the low voltage is not supplied from the low voltage power supply 4000 due to some malfunction, the backup voltage Vb can be supplied from the backup power supply circuit 700.

[0033] Figure 4 It is a diagram showing a wiring pattern of the power conversion device 1000 in the first embodiment. The substrate 600 is divided into a high voltage side 600H and a low voltage side 600L, and the backup power supply circuit 700 and the gate power supply circuit 800 are separated into the high voltage side 600H and the low voltage side 600L by an insulating element 600a such as an insulating transformer TB1. The gate drive circuit 900 is arranged on the high voltage side 600H of the substrate 600, and the controller 910 is arranged in the circuit area 600R on the low voltage side 600L of the substrate 600. In addition, the inverter circuit 400 is connected between the positive bus P and the negative bus N, and the switching elements 411 and 421 in the inverter circuit 400 are connected to the wiring pattern on the substrate 600, but the connection state thereof is omitted.

[0034] The gate drive circuit 900 supplies the startup voltage Va to the backup power supply circuit 700. The grounds GND1, GND2, and GND3 of the gate drive circuit 900, that is, the emitter 412E of the switching element 421 are connected to the ground GND0 in the backup power supply circuit 700 via the gate drive circuit 900.

[0035] The low voltage power supply 4000 supplies a low voltage to the electronic components of the circuit area 600R on the low voltage side 600L such as the controller 910. The high voltage power supply 2000 supplies a high voltage to the electronic components on the high voltage side 600H of the power conversion device 1000 via the positive bus P and the negative bus N. The negative bus N is connected to the grounds GND1, GND2, and GND3 based on the emitter 412E of the switching element 421.

[0036] That is, in the present embodiment, the ground GND0 of the backup power supply circuit 700 is connected to the emitter reference grounds GND1, GND2, and GND3 of the gate drive circuit 900, and the emitter reference grounds GND1, GND2, and GND3 are connected to the negative electrode of the high voltage power supply 2000 via the negative electrode bus N. Thus, compared with the case where the ground GND0 of the backup power supply circuit 700 is directly connected to the negative electrode bus N, the operations of the gate drive circuit 900 and the backup power supply circuit 700 can be stabilized.

[0037] Figure 5 1 is a diagram showing a wiring pattern of a power conversion device 1000 in a comparative example. Figure 5 The comparative example shown is an example not applying the first embodiment but is an example for comparison with the first embodiment. Figure 4 The same parts are denoted by the same symbols and their descriptions are simplified.

[0038] like Figure 5 As shown in FIG. 1 , in the comparative example, the ground GND0 of the backup power supply circuit 700 is connected to the negative bus N. In this case, a loop current is generated between the emitter of the gate drive circuit 900 and the negative bus N which is the ground GND0 of the backup power supply circuit 700, and a potential difference is generated between the gate drive circuit 900 and the backup power supply circuit 700. Therefore, the operation of the gate drive circuit 900 becomes unstable. On the other hand, according to Figure 4 In the present embodiment shown, the operations of the gate driving circuit 900 and the backup power supply circuit 700 can be stabilized.

[0039] According to the first embodiment of the present invention, the backup power supply circuit 700 is started by using the gate power supply circuit 800 that supplies power to the gate drive circuit 900. Therefore, the startup circuit separately provided for starting the backup power supply circuit can be omitted, thereby reducing component costs and the mounting area on the substrate.

[0040] [Second embodiment] Figure 61 is an overall configuration diagram of a power conversion device 1000 in the second embodiment. In the first embodiment, an example of supplying a backup voltage from a backup power supply circuit to a gate power supply circuit and a controller is shown, but in the second embodiment, a backup voltage is supplied from a backup power supply circuit to a controller, and a high voltage is supplied to a gate power supply circuit. Figure 1 The same parts are denoted by the same symbols and their descriptions are simplified.

[0041] The backup power supply circuit 700, the gate power supply circuit 800, the gate drive circuit 900, the controller 910, and the voltage conversion circuit 920 are arranged on the substrate 600. The substrate 600 is divided into a high voltage side 600H and a low voltage side 600L by an insulating element 600a, and the backup power supply circuit 700 is separated into a high voltage side 600H and a low voltage side 600L by an insulating element 600a such as a transformer. The gate power supply circuit 800, the gate drive circuit 900, and the voltage conversion circuit 920 are arranged on the high voltage side 600H, and the controller 910 is arranged on the low voltage side 600L of the substrate 600.

[0042] The backup power supply circuit 700 controls the current supplied to the primary winding of the isolation transformer based on the power supplied from the high voltage power supply 2000 via the positive bus P and the negative bus N, generates a backup voltage instead of the low voltage supplied from the low voltage power supply 4000, and supplies it to the controller 910 via the diode D2. The backup power supply circuit 700 is started by supplying the startup voltage output from the gate power supply circuit 800 via the backflow prevention diode D0 and the current limiting resistor R0. In the case of abnormal voltage in the backup power supply circuit 700, the backflow prevention diode D0 and the current limiting resistor R0 prevent the gate power supply circuit 800 from becoming overloaded and over-voltage.

[0043] The controller 910 is normally supplied with a low voltage from the low voltage power supply 4000, but when the low voltage is not supplied from the low voltage power supply 4000 due to some malfunction, a backup voltage is supplied instead of the low voltage from the backup power supply circuit 700. The backup power supply circuit 700 will be described in detail later.

[0044] The gate power supply circuit 800 generates a gate drive voltage for operating the gate drive circuit 900 based on the power supplied from the high voltage power supply 2000 via the positive bus P and the negative bus N, and supplies the generated gate drive voltage to the gate drive circuit 900. The gate drive circuit 900 drives the switching elements 411 and 421 based on the drive signal Pw output from the controller 910.

[0045] In the first embodiment, the emitters of the switching elements 421 of each phase of the lower arm are connected to the ground in the gate drive circuit 900 , but are not connected in this embodiment. Also, the ground in the gate drive circuit 900 is not connected to the ground in the backup power supply circuit 700 .

[0046] The voltage conversion circuit 920 steps down the high voltage supplied from the high voltage power supply 2000 via the positive bus P and the negative bus N to a predetermined operating voltage for operating the gate power supply circuit 800. When the operating voltage supplied from the voltage conversion circuit 920 exceeds a predetermined value, the gate power supply circuit 800 outputs a startup voltage to the backup power supply circuit 700 via the reverse current prevention diode D0 and the current limiting resistor R0, thereby starting the backup power supply circuit 700.

[0047] Figure 7 It is a detailed configuration diagram of the main parts of the power conversion device 1000 in the second embodiment. In this Figure 7 , the gate power supply circuit 800 and the gate drive circuit 900 corresponding to the switching element 421 of the lower arm are shown, and the gate power supply circuit 800 and the gate drive circuit 900 corresponding to the switching element 411 of the upper arm are omitted. Figure 2 The same parts are denoted by the same symbols and their descriptions are simplified.

[0048] The backup power supply circuit 700 includes a first power supply IC 710 and an isolation transformer TB1. Power is supplied from a high voltage power supply 2000 to one end of a primary winding Nb1 of the isolation transformer TB1 via a positive bus P. At the other end of the primary winding Nb1 of the isolation transformer TB1, a field effect transistor FE1 is connected to a ground GND0 of the first power supply IC 710 via a resistor R1. The ground GND0 is connected to a negative bus N.

[0049] The first power IC 710 starts up when the startup voltage Va generated by the gate power circuit 800 is supplied to the power terminal Vcc of the first power IC 710 via the reverse current prevention diode D0 and the current limiting resistor R0. Then, the field effect transistor FE1 is switched by the signal output from the signal terminal SW, and the backup voltage Vb is generated by flyback operation using the secondary winding Nb2 of the isolation transformer TB1, the diode, and the capacitor. The backup voltage Vb is supplied to the controller 910.

[0050] In addition, an auxiliary winding Nbc is provided in the isolation transformer TB1, and a feedback voltage Vf1 is generated using an output voltage from the auxiliary winding Nbc. The feedback voltage Vf1 is supplied to the power supply terminal Vcc of the first power supply IC 710 via a diode, and is divided into a predetermined voltage and input to the feedback terminal FB of the first power supply IC 710. The first power supply IC 710 performs switching control on the field effect transistor FE1 in such a manner that the divided voltage of the feedback voltage Vf1 input to the feedback terminal FB becomes a predetermined set voltage. Here, similarly to the first embodiment, since the voltage of the feedback voltage Vf1 is set to a voltage higher than the start-up voltage Va, the operation of the first power supply IC 710 is continued using the power from the feedback voltage Vf1 after the first power supply IC 710 is started.

[0051] The voltage conversion circuit 920 is formed by connecting a series circuit of a field effect transistor FE3 and a Zener diode Z3 between the positive bus P and the negative bus N. In addition, the voltage from the positive bus P is input to the gate of the field effect transistor FE3 via the resistor R3. The connection point between the field effect transistor FE3 and the Zener diode Z3 is input to the power supply terminal Vcc of the second power supply IC810 via the diode D3. The voltage conversion circuit 920 converts the voltage from the high voltage power supply 2000 into the operating voltage of the second power supply IC810 of the gate power supply circuit 800. In addition, the output from the connection point between the field effect transistor FE3 and the Zener diode Z3 of the voltage conversion circuit 920 is also supplied to the gate power supply circuit 800 corresponding to the switching element 411 of the upper arm of which the figure is omitted.

[0052] The gate power supply circuit 800 includes a second power supply IC 810 and an isolation transformer TG1. The second power supply IC 810 is activated when the operating voltage supplied from the voltage conversion circuit 920 to the power supply terminal Vcc exceeds a specified value, and switches the field effect transistor FE2 according to the signal output from the signal terminal SW, and generates a gate drive voltage by flyback operation using the secondary winding Ng2 of the isolation transformer TG1, a diode, and a capacitor. The three gate drive circuits GD1, GD2, and GD3 that drive the switch element 421 of the lower arm are provided with three secondary windings Ng2 of the isolation transformer TG1, and the gate drive voltages are generated respectively.

[0053] In addition, an auxiliary winding Ngc is provided in the isolation transformer TG1, and the feedback voltage Vf2 generated by the output voltage from the auxiliary winding Ngc is divided and input to the feedback terminal FB of the second power supply IC810. After the second power supply IC810 of the gate power supply circuit 800 is started due to the operating voltage supplied from the voltage conversion circuit 920 exceeding the prescribed value, the field effect transistor FE2 is switched so that the divided voltage of the feedback voltage Vf2 input to the feedback terminal FB becomes a prescribed set voltage. In addition, the feedback voltage Vf2 is also input to the power supply terminal Vcc of the second power supply IC810 via the diode D4. That is, the feedback voltage Vf2 or the operating voltage from the voltage conversion circuit 920 is supplied to the power supply terminal Vcc of the second power supply IC810.

[0054] Here, the voltage of the feedback voltage Vf2 is set to a voltage higher than the operating voltage from the voltage conversion circuit 920, so after the second power supply IC 810 is started, the power from the feedback voltage Vf2 is used to continue the operation of the second power supply IC 810. In addition, the feedback voltage Vf2 is input as the starting voltage Va to the power supply terminal Vcc of the first power supply IC 710 in the backup power supply circuit 700 via the reverse current prevention diode D0 and the current limiting resistor R0, and the backup power supply circuit 700 is started. That is, after the operating voltage supplied from the voltage conversion circuit 920 exceeds the specified value, the gate power supply circuit 800 generates the starting voltage Va and starts the backup power supply circuit 700.

[0055] The gate drive circuit 900 shows three gate drive circuits GD1, GD2, and GD3 that drive the switch element 421 of the lower arm. The drive signal Pw output from the controller 910 is input to the base of the switch element 421, turning the switch element 421 on and off for driving. In addition, the three gate drive circuits that drive the switch element 411 of the upper arm (not shown) have the same structure.

[0056] Figure 8 (A)~ Figure 8 (G) is a timing chart showing the operations of the backup power supply circuit 700 and the gate power supply circuit 800 in the second embodiment. Figure 8 (A) indicates the high voltage supplied from the high voltage power supply 2000. Figure 8 (B) represents the operating voltage of the second power supply IC 810 supplied from the voltage conversion circuit 920. Figure 8 (C) represents a signal output from the signal terminal SW of the second power supply IC810, Figure 8 (D) represents the feedback voltage Vf2 generated by the gate power supply circuit 800, Figure 8 (E) represents a signal output from the signal terminal SW of the first power supply IC710, Figure 8(F) represents the feedback voltage Vf1 generated by the backup power supply circuit 700, Figure 8 (G) represents the backup voltage Vb generated by the backup power supply circuit 700 .

[0057] Below, refer to Figure 7 The detailed configuration diagram of the main parts of the power conversion device 1000 shown in FIG. When the contactor 4001 is turned on, a low voltage is supplied from the low voltage power supply 4000, and the controller 910 can operate. Figure 8 As shown in (A), a high voltage is supplied from the high voltage power supply 2000 to the voltage conversion circuit 920. As a result, the output voltage of the voltage conversion circuit 920 gradually increases from 0V to 12V. 12V is an example of a low voltage. Then, when the voltage reaches the starting voltage vi of the second power IC 810 of the gate power supply circuit 800, as shown in FIG. Figure 8 As shown in (C), the gate power supply circuit 800 is started.

[0058] The gate power supply circuit 800 is started, as Figure 8 As shown in (D), when the feedback voltage Vf2 is greater than the voltage vj at which the first power IC 710 of the backup power supply circuit 700 can operate, as shown in Figure 8 As shown in (E), the first power supply IC 710 starts the switching control operation. The 16V of the feedback voltage Vf2 is an example.

[0059] When the first power supply IC 710 starts to operate and performs switching control of the field effect transistor FE1, Figure 8 As shown in (F) of FIG. 1 , a feedback voltage Vf1 is generated. At this time, the feedback voltage Vf1 is controlled to be a voltage higher than the start voltage Va, for example, 17V. Figure 8 As shown in (G), the backup power supply circuit 700 generates a backup voltage Vb. The backup voltage Vb is, for example, 8 V. The contactor 2001 is turned on, and after a time Tb, the backup power supply circuit 700 becomes an operating state. Since power is supplied to the backup power supply circuit 700 from the high voltage power supply 2000, even if the low voltage is not supplied from the low voltage power supply 4000 due to some malfunction, the backup voltage Vb can be supplied from the backup power supply circuit 700.

[0060] According to the second embodiment of the present invention, the gate power supply circuit 800 is started by the voltage conversion circuit 920, and the backup power supply circuit 700 is started by the started gate power supply circuit 800. Therefore, the starting circuit separately provided for starting the backup power supply circuit can be omitted, thereby reducing the component cost and the mounting area on the substrate.

[0061] In addition, in the first embodiment, when the supply of the low voltage from the low voltage power supply 4000 is stopped from the beginning due to some kind of malfunction, the gate power supply circuit 800 cannot be started, and therefore the backup power supply circuit 700 cannot be started. On the other hand, in the second embodiment, even when the supply of the low voltage from the low voltage power supply 4000 is stopped from the beginning due to some kind of malfunction, the operating voltage of the second power supply IC 810 can be generated by converting the high voltage supplied from the high voltage power supply 2000 by the voltage conversion circuit 920, and the gate power supply circuit 800 can be started using the operating voltage. Then, the backup power supply circuit 700 can be started using the starting voltage Va (feedback voltage Vf2) output from the gate power supply circuit 800 after startup. Therefore, according to the second embodiment, the availability of the power conversion device 1000 can be further improved.

[0062] According to the above-described embodiment, the following effects can be obtained. (1) The power conversion device 1000 includes: switching elements 411 and 42, whose upper and lower arms are connected in series; a gate drive circuit 900, which drives the switching elements 411 and 42; a controller 910, which operates using a predetermined low voltage supplied from a low voltage power supply 4000 and outputs a drive signal Pw for driving the switching elements 411 and 42 to the gate drive circuit 900; a gate power supply circuit 800, which generates a gate drive voltage for operating the gate drive circuit 900 and supplies the generated gate drive voltage to the gate drive circuit 900; and a backup power supply circuit 700, which controls the current supplied from the high voltage power supply (2000) to the primary winding of the isolation transformer (TB1) to generate a backup voltage Vb instead of the low voltage, supplies the generated backup voltage Vb to the controller 910, and the backup power supply circuit 700 is started by the start-up voltage Va output from the gate power supply circuit 800. As a result, a start-up circuit for starting the backup power supply circuit can be omitted.

[0063] The present invention is not limited to the above-described embodiments, and other embodiments that can be considered within the scope of the technical concept of the present invention are also included in the scope of the present invention as long as the features of the present invention are not impaired. In addition, a configuration combining the above-described embodiments is also possible. Explanation of symbols

[0064] 200…voltage detector, 300…DC current detector, 400…inverter circuit, 410…power module, 411, 421…switching element, 412, 422…diode, 500…output current detector, 600…substrate, 600a…insulating element, 600H…high voltage side of substrate, 600L…low voltage side of substrate, 700…backup power supply circuit, 710…first power supply IC, 800…gate power supply circuit, 810…second power supply IC, 900, GD1, GD2, GD3…gate drive circuit, 910…controller, 1 000…power conversion device, 2000…high voltage power supply, 2001…contactor, 3000…motor, 4000…low voltage power supply, 4001…contactor, TB1, TG1…insulation transformer, FE1, FE2…field effect transistor, R1, R2…resistor, Vcc…power supply terminal, SW…signal terminal, FB…feedback terminal, Va…starting voltage, Vb…backup voltage, D0…reverse current prevention diode, R0…current limiting resistor, GND1, GND2, GND3…grounding, P…positive bus, N…negative bus, Pw…drive signal.

Claims

1. A power conversion device, characterized in that: have: A switching element, the upper and lower arms of which are connected in series; A gate driving circuit, which drives the switching element; a controller that operates by a predetermined low voltage supplied from a low voltage power source and outputs a drive signal for driving the switching element to the gate drive circuit; a gate power supply circuit that generates a gate drive voltage for operating the gate drive circuit and supplies the generated gate drive voltage to the gate drive circuit; as well as a backup power supply circuit that controls the current supplied from the high voltage power supply to the primary winding of the isolation transformer, generates a backup voltage instead of the low voltage, and supplies the generated backup voltage to the controller, The backup power supply circuit is activated by a startup voltage output from the gate power supply circuit.

2. The power conversion device according to claim 1, characterized in that: The gate power supply circuit generates the gate drive voltage from the low voltage, and outputs the generated gate drive voltage as the startup voltage to the backup power supply circuit.

3. The power conversion device according to claim 2, characterized in that: The backup power supply circuit supplies the backup voltage to the gate power supply circuit and the controller.

4. The power conversion device according to claim 2, characterized in that: The gate power supply circuit generates the gate drive voltage and activates the backup power supply circuit after the low voltage supplied from the low voltage power supply exceeds a predetermined value.

5. The power conversion device according to any one of claims 1 to 4, characterized in that: The ground of the backup power supply circuit is connected to the emitter-referenced ground of the gate drive circuit, and the emitter-referenced ground is connected to the negative electrode of the high-voltage power supply via a bus bar.

6. The power conversion device according to claim 1, characterized in that: The gate power supply circuit generates the gate drive voltage and the startup voltage according to a prescribed high voltage supplied from the high voltage power supply, and outputs the generated startup voltage to the backup power supply circuit.

7. The power conversion device according to claim 6, characterized in that: A voltage conversion circuit is provided for converting the high voltage supplied from the high voltage power supply into an operating voltage of the gate power supply circuit. The gate power supply circuit operates using the operating voltage supplied from the voltage conversion circuit.

8. The power conversion device according to claim 7, characterized in that: The gate power supply circuit generates the startup voltage and starts the backup power supply circuit after the operating voltage supplied from the voltage conversion circuit exceeds a predetermined value.

9. The power conversion device according to claim 1, characterized in that: The backup power supply circuit includes a power supply IC that controls a current supplied from the high-voltage power supply to the primary winding of the isolation transformer, and the power supply IC is activated by receiving the startup voltage output from the gate power supply circuit.

10. The power conversion device according to claim 9, characterized in that: The startup voltage generated by the gate power supply circuit is supplied to a power supply terminal of the power supply IC via a reverse current prevention diode and a current limiting resistor.

11. The power conversion device according to claim 10, characterized in that: The backup power supply circuit generates a feedback voltage according to a current supplied from the high voltage power supply to the primary winding of the isolation transformer, After the power supply IC is activated by receiving the activation voltage, the feedback voltage generated by the backup power supply circuit is supplied to the power supply terminal.

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