POWER CONVERSION DEVICE

Abstract

A power conversion device is provided, comprising: a switching element connected in series with upper and lower branches; a gate drive circuit configured to drive the switching element; a controller configured to operate at a predetermined low voltage supplied by a low-voltage power supply and to output a drive signal to the gate drive circuit for driving the switching element; a gate power supply circuit configured to generate a gate drive voltage for operating the gate drive circuit and to supply the generated gate drive voltage to the gate drive circuit;and a backup power supply circuit configured to control a current supplied from a high-voltage power supply to a primary winding of an isolation transformer to generate a backup voltage instead of the low voltage, and to supply the generated backup voltage to the controller. The backup power supply circuit is further started with a start voltage output by the gate power supply circuit.

Description

Technical field

[0001] The present invention relates to a power conversion device. State of the art

[0002] A power conversion device that converts DC power into AC power includes upper and lower branch series circuits for a plurality of phases. The upper and lower branch series circuits are formed by connecting an upper branch switching element and a lower branch switching element in series. The switching element is also controlled by a drive signal output from a controller via a gate drive circuit. In addition, the controller is usually supplied with power from a low-voltage power supply but also includes a backup power supply circuit to ensure operation even if the low-voltage power supply is interrupted. The power of the backup power supply circuit is supplied from a high-voltage power supply, which is different from the low-voltage power supply.In this case, it is necessary to provide a starting circuit that lowers a voltage of the high-voltage power supply to start the backup power supply circuit.

[0003] For this purpose, PTL 1 discloses an inverter control circuit that turns on a specific switching element even when a low-voltage power supply becomes abnormal, without adding a dedicated microcomputer. PTL 2 also discloses a device that controls an inverter without feedback control even when the power of a control circuit of the inverter is interrupted, while preventing the device from being upsized. Literature listPatent literature PTL 1: JP 2017-118815 A PTL 2: JP 2015-159684 A Summary of the inventionTechnical problem

[0004] However, in the devices disclosed in PTL 1 and 2, the omission of a start circuit for starting a backup power supply circuit is not mentioned. Solution to the problem

[0005] According to one aspect of the present invention, a power conversion device comprises: a switching element connected in series with upper and lower arms; a gate drive circuit configured to drive the switching element; a controller configured to operate with a predetermined low voltage supplied from a low-voltage power supply and to output a drive signal for driving the switching element to the gate drive circuit; a gate power supply circuit configured to generate a gate drive voltage for operating the gate drive circuit and to supply the generated gate drive voltage to the gate drive circuit;and a backup power supply circuit configured to control a current supplied from a high-voltage power supply to a primary winding of an isolation transformer to generate a backup voltage in place of the low voltage, and to supply the generated backup voltage to the controller. The backup power supply circuit is further started with a starting voltage output from the gate power supply circuit. Advantageous effects of the invention

[0006] According to the present invention, the start circuit that starts the backup power supply circuit can be omitted. Brief description of the drawings [ Fig. 1] Fig. 1 is a diagram illustrating an overall configuration of a power conversion device according to a first embodiment. [ Fig. 2] Fig. 2 is a diagram illustrating a detailed configuration of main units of the power conversion device according to the first embodiment. [ Fig. 3] Fig. 3(A) to Fig. 3(F) are timing charts illustrating an operation of a backup power supply circuit according to the first embodiment. [ Fig. 4] Fig. 4 is a diagram illustrating a wiring pattern of the power conversion device according to the first embodiment. [ Fig. 5] Fig. 5 is a diagram illustrating a wiring pattern of a power conversion device according to a comparative example. [ Fig. 6] Fig. 6 is a diagram illustrating an overall configuration of a power conversion device according to a second embodiment. [ Fig. 7] Fig. 7 is a diagram illustrating a detailed configuration of main units of the power conversion device according to the second embodiment. [ Fig. 8] Fig. 8(A) to Fig. 8(G) are timing charts illustrating operations of a backup power supply circuit and a gate power supply circuit according to the second embodiment.

[0007] Embodiments of the present invention will be described below with reference to the drawings. The following description and drawings are intended as examples for describing the present invention and have been omitted and simplified where appropriate for the sake of clarity. The present invention can also be implemented in various other forms. Furthermore, unless otherwise stated, the number of constituent elements may be singular or plural. [First embodiment]

[0008] Fig. 1 is a diagram illustrating an overall configuration of a power conversion device 1000 according to a first embodiment.

[0009] The power conversion device 1000 converts DC power supplied from a DC high-voltage power supply 2000, such as a battery, into AC power and drives a motor 3000. The high-voltage power supply 2000 itself further supplies DC power between a positive electrode busbar P and a negative electrode busbar N of the power conversion device 1000 via a contactor 2001. The motor 3000 is, for example, a three-phase induction motor and is used as a drive source of a vehicle. Furthermore, the motor 3000 is provided with an angle sensor 3001, such as a resolver, that outputs a rotation angle.

[0010] The power conversion device 1000 further includes a capacitor module 100 connected in parallel between the positive electrode busbar P and the negative electrode busbar N and smoothing a direct current, a voltage detector 200 that detects a direct voltage between the positive electrode busbar P and the negative electrode busbar N, and an inverter circuit 400 that performs power conversion. Furthermore, a direct current detector 300 that detects a direct current flowing through the positive electrode busbar P is included. Furthermore, 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.

[0011] The backup power supply circuit 700, the gate power supply circuit 800, the gate drive circuit 900, and the controller 910 are further arranged on a substrate 600. The substrate 600 is divided into a high-voltage side 600H and a low-voltage side 600L. Furthermore, the backup power supply circuit 700 and the gate power supply circuit 800 are also divided into a high-voltage side 600H and a low-voltage side 600L by an insulation element 600a, such as a transformer. The gate drive circuit 900 is further 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.

[0012] The inverter circuit 400 includes a power module 410 that configures an upper and lower arm series circuit formed by a switching element 411 and a diode 412 functioning as an upper arm, and a switching element 421 and a diode 422 functioning as a lower arm. Specifically, the power module 410 is provided for three phases (U-phase, V-phase, and W-phase) corresponding to phase windings of the motor 3000. That is, the inverter circuit 400 includes arms for three phases formed by connecting the upper arm switching element 411 and the lower arm switching element 421 in series between the positive electrode busbar P and the negative electrode busbar N of direct current. Accordingly, an example of three phases will be described as follows. For example, the power modules 410 can be provided for a plurality of phases according to the number of phases of the motor 3000.

[0013] Emitter detection terminals are provided in the upper arm switching element 411 and the lower arm switching element 421, and the emitter detection terminals are connected to the gate drive circuit 900 to detect currents flowing through the switching elements 411 and 421.

[0014] The emitter of the switching element 421 of the lower arm is further connected to a ground GND3 in the gate drive circuit 900. The emitters of the switching elements 421 of the lower arms of the other phases are also similarly connected to grounds GND2 and GND1 in the gate drive circuit 900.

[0015] A drive signal Pw, which is a PWM signal output from the controller 910, is input to base terminals of the switching elements 411 and 421 via the gate drive circuit 900.

[0016] The switching elements 411 and 421 are power semiconductor elements which consist, for example, of an insulated gate bipolar transistor (IGBT), a metal oxide semiconductor field effect transistor (MOSFET), a super junction metal oxide semiconductor field effect transistor (SJ-MOSFET), silicon carbide (SiC), gallium nitride (GaN) or the like.

[0017] The output current detector 500 detects an AC output from a connection point between the upper arm switching element and the lower arm switching element for each phase and outputs each detection value to the controller 910.

[0018] Furthermore, a DC low-voltage power supply 4000, such as a battery, is provided outside the power conversion device 1000. A contactor 4001 is turned on according to an ignition key of a vehicle, and a low voltage is supplied to the controller 910 from the low-voltage power supply 4000 via a diode D1. Subsequently, the drive signal Pw is output to the gate drive circuit 900 in response to a torque command from a host controller (not shown), a detection voltage from the voltage detector 200, a DC detection value from the DC detection value 300, an output current detection value from the output current detector 500, and a rotation angle from the angle sensor 3001.

[0019] The backup power supply circuit 700 further controls a current supplied to the primary winding of the isolation transformer based on power supplied from the high-voltage power supply 2000 via the positive electrode busbar P, generates a backup voltage in place of a low voltage supplied from the low-voltage power supply 4000, and supplies the backup voltage to the controller 910 and the gate power supply circuit 800 via a diode D2. To this end, the backup power supply circuit 700 is started by supplying a starting voltage (details of which will be described below) output from the gate power supply circuit 800 via a backflow prevention diode D0 and a current limiting resistor R0.The backflow prevention diode D0 and the current limiting resistor R0 prevent the gate power supply circuit 800 from being overloaded and from overvoltage when the voltage of the backup power supply circuit 700 becomes abnormal. Details of the backup power supply circuit 700 will be described further below.

[0020] The gate power supply circuit 800 generates a gate drive voltage for driving the gate drive circuit 900 based on the low voltage from the low-voltage power supply 4000 or the reserve voltage from the reserve power supply circuit 700, and supplies the generated gate drive voltage to the gate drive circuit 900. Normally, a voltage lower than that of the low-voltage power supply 4000 is supplied to the gate power supply circuit 800 and the controller 910. However, when the voltage lower than that of the low-voltage power supply 4000 is not supplied due to a fault, a reserve voltage is supplied instead of the low voltage from the reserve power supply circuit 700.

[0021] For this purpose, 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 based on the drive signal Pw output from the controller 910. The grounds GND1, GND2, and GND3 in the gate drive circuit 900 are further connected to the ground GND0 in the backup power supply circuit 700. Details of the gate drive circuit 900 will be described below.

[0022] Fig. 2 is a diagram illustrating a detailed configuration of main units of the power conversion device 1000 according to the first embodiment.

[0023] In Fig. In Figure 2, the power module 410 is illustrated only for one phase, whereas the other phases are not shown. Similarly, the gate power supply circuit 800 and the gate drive circuit 900 corresponding to the lower-arm switching element 421 are also illustrated, whereas the gate power supply circuit 800 and the gate drive circuit 900 corresponding to the upper-arm switching element 411 are not shown.

[0024] The backup power supply circuit 700 includes a first power supply IC 710 and an isolation transformer TB1. Power is supplied to one end of a primary winding Nb1 of the isolation transformer TB1 from the high-voltage power supply 2000 via the positive electrode busbar P. At the other end of the primary winding Nb1 of the isolation transformer TB1, the field-effect transistor FE1 is also connected to ground GND0 via a resistor R1.

[0025] The first power supply IC 710 is started when the starting voltage Va generated by the gate power supply circuit 800 is supplied to a power supply terminal Vcc via the backflow prevention diode D0 and the current limiting resistor R0. Subsequently, the switching of the field-effect transistor FE1 is controlled with a signal output from the signal terminal SW, and a reserve voltage Vb is generated by a flyback operation using a secondary winding Nb2, a diode, and a capacitor of the isolation transformer TB1. The reserve voltage Vb itself is supplied to the controller 910 and the gate power supply circuit 800. In addition, the reserve voltage Vb is also supplied to the gate power supply circuit 800 corresponding to the upper-arm switching element 411 (not shown).

[0026] The isolation transformer TB1 is provided with an auxiliary winding Nbc, and a feedback voltage Vf is generated using an output voltage from the auxiliary winding Nbc. The feedback voltage Vf is supplied to the power supply terminal Vcc of the first power supply IC 710 via the diode, divided, and input to a feedback terminal FB of the first power supply IC 710. The first power supply IC 710 further performs switching control on the field-effect transistor FE1 such that a divided voltage of the feedback voltage Vf input to the feedback terminal FB becomes a predetermined target voltage.Here, since the voltage of the feedback voltage Vf is set to a voltage higher than the starting voltage Va, the operation of the first power supply IC 710 continues using the power from the feedback voltage Vf after the first power supply IC 710 is started. Accordingly, the first power supply IC 710 continues operating with the feedback voltage Vf after the first power supply IC 710 is started with the starting voltage Va generated by the gate power supply circuit 800.

[0027] The gate power supply circuit 800 further includes a second power supply IC 810 and an isolation transformer TG1. In the second power supply IC 810, a low voltage from the low-voltage power supply 4000 or the backup voltage Vb from the backup power supply circuit 700 is supplied to the power supply terminal Vcc. One end of the primary winding Ng1 of the isolation transformer TG1 is connected to the power supply terminal Vcc of the second power supply IC 810. At the other end of the primary winding Ng1, the field-effect transistor FE2 is further connected to the ground GND4 on the low-voltage side via a resistor R2.

[0028] The second power supply IC 810 performs switching control on the field-effect transistor FE2 by a signal output from the signal terminal SW, and generates a gate drive voltage through a flyback operation using the secondary winding Ng2, the diode, and the capacitor of the isolation transformer TG1. Three secondary windings Ng2 of the isolation transformer TG1 are provided corresponding to the three gate drive circuits GD1, GD2, and GD3 that drive the lower-arm switching element 421 and each generate a gate drive voltage. Among these, a gate drive voltage supplied to a gate drive circuit GD3 is supplied as the starting voltage Va to the backup power supply circuit 700 via the backflow prevention diode D0 and the current limiting resistor R0.Accordingly, it is not necessary to separately provide a start-up circuit that starts the backup power supply circuit 700. The isolation transformer TG1 is further provided with an auxiliary winding Ngc, and a feedback voltage generated using an output voltage from the auxiliary winding Ngc is input to the feedback terminal FB of the second power supply IC 810. The second power supply IC 810 performs switching control on the field-effect transistor FE2 such that the feedback voltage input to the feedback terminal FB becomes a predetermined target voltage.

[0029] The gate drive circuit 900 also shows three gate drive circuits GD1, GD2, and GD3 that drive the switching element 421 of the lower arm. Here, in the gate drive circuit GD3, the emitter of the switching element 421 is connected to the ground GND3, the base of the switching element 421 is connected to a terminal of the drive signal Pw, and an emitter sense is connected to a terminal Es. The same also applies to the gate drive circuits GD1 and GD2. The drive signal Pw output from the controller 910 is input to the base of the switching element 421, and the switching element 421 is turned on and off to be driven. A current flowing through the switching element 421 is also transmitted from the emitter detection to the controller 910 via the gate drive circuit GD3, and the controller 910 controls an overcurrent or the like.

[0030] The gate drive circuits GD1, GD2, and GD3 drive the switching elements 421 in the lower arms of the respective phases, and the grounds GND1, GND2, and GND3 of the gate drive circuits GD1, GD2, and GD3, that is, the emitters of the switching elements 421 in the lower arms of the respective phases, are connected to the ground GND0 in the backup power supply circuit 700. The reason for this will be described below.

[0031] Fig. 3(A) to Fig. 3(F) are timing charts illustrating an operation of the backup power supply circuit 700 according to the first embodiment. Fig. 3(A) illustrates a low voltage supplied by the low voltage power supply 4000, Fig. 3(B) illustrates a starting voltage Va supplied by the gate drive circuit GD3, Fig. 3(C) illustrates a signal output from the signal terminal SW of the first power supply IC 710, Fig. 3(D) illustrates a high voltage supplied by the high voltage power supply 2000, Fig. 3(E) illustrates a feedback voltage Vf generated by the backup power supply circuit 700, and Fig. 3(F) illustrates a reserve voltage Vb generated by the reserve power supply circuit 700.

[0032] The following is a description with reference to a diagram of a detailed configuration of main units of the power conversion device 1000 as shown in Fig. 2 is provided.

[0033] When contactor 4001 is switched on, a low voltage is supplied by the low voltage power supply 4000. As shown in Fig. As illustrated in Figure 3(A), a voltage input to the controller 910 and the gate power supply circuit 800 gradually increases from 0 V to 12 V. 12 V is an example of the low voltage. Subsequently, when this voltage reaches a starting voltage vi of the second power supply IC 810 of the gate power supply circuit 800, the gate power supply circuit 800 is started, as shown in Fig. 3(B) illustrates.

[0034] Here, when the gate power supply circuit 800 is started and the starting voltage Va becomes higher than an operating voltage vj of the first power supply IC 710 of the backup power supply circuit 700, as shown in Fig. 3(B), the first power supply IC 710 starts an operation of the switching control as shown in Fig. 3(C). The starting voltage Va of 15 V is also an example.

[0035] In addition, when the contactor 2001 is switched on, the high voltage power supply 2000 gradually increases to, for example, 400 V, as shown in Fig. 3(D), and supplies power to the reserve power supply circuit 700. Accordingly, as shown in Fig. 3(E), a high voltage is applied to the primary winding Nb1 of the isolation transformer TB1 to generate the feedback voltage Vf. The feedback voltage Vf is further controlled to a voltage higher than the starting voltage Va, for example, 16 V, by switching control of the field effect transistor FE1 performed by the first power supply IC 710. Furthermore, the backup power supply circuit 700 generates the backup voltage Vb, as shown in Fig. 3(F). The reserve voltage Vb is, for example, 8 V. Furthermore, the contactor 4001 is turned on, and the reserve power supply circuit 700 enters an operating state after a time Tb. Thus, power is supplied from the high-voltage power supply 2000 to the reserve power supply circuit 700. Therefore, the reserve voltage Vb is supplied from the reserve power supply circuit 700 even when the low voltage is not supplied from the low-voltage power supply 4000 due to a fault.

[0036] Fig. 4 is a diagram illustrating a wiring pattern of the power conversion device 1000 according to the first embodiment.

[0037] The substrate 600 is divided into a high-voltage side 600H and a low-voltage side 600L. The backup power supply circuit 700 and the gate power supply circuit 800 are further divided into a high-voltage side 600H and a low-voltage side 600L by an isolation element 600a, such as the isolation transformer TB1. Furthermore, 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 region 600R on the low-voltage side 600L of the substrate 600. In addition, although the inverter circuit 400 is connected between the positive electrode busbar P and the negative electrode busbar N, and the switching elements 411 and 421 in the inverter circuit 400 are connected to the wiring pattern on the substrate 600, a connection state thereof is avoided.

[0038] The gate drive circuit 900 supplies the starting voltage Va to the backup power supply circuit 700. In addition, the grounds GND1, GND2, and GND3 of the gate drive circuit 900, that is, an 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.

[0039] The low-voltage power supply 4000 supplies a low voltage to electronic components of the circuit portion 600R on the low-voltage side 600L, such as the controller 910. The high-voltage power supply 2000 also supplies a high voltage to electronic components on the high-voltage side 600H of the power conversion device 1000 via the positive electrode bus bar P and the negative electrode bus bar N. Further, the negative electrode bus bar N is connected to the grounds GND1, GND2, and GND3 based on the emitter 412E of the switching element 421.

[0040] 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 bar N. Accordingly, the operations of the gate drive circuit 900 and the backup power supply circuit 700 can be stabilized compared to a case where the ground GND0 of the backup power supply circuit 700 is directly connected to the negative electrode bus bar N.

[0041] Fig. 5 is a diagram illustrating a wiring pattern of the power conversion device 1000 according to a comparative example. Fig. The comparative example illustrated in Figure 5 is an example to which the first embodiment is not applied, and thus serves as a comparison with the first embodiment. Furthermore, in this case, the same portions as those in Fig. 4 are provided with the same reference numerals and their description is simplified below.

[0042] As in Fig. 5, in the comparative example, the ground GND0 of the backup power supply circuit 700 is connected to the negative electrode bus bar N. In this case, a loop current is generated between the emitter of the gate drive circuit 900 and the negative electrode bus bar N, which is the ground GND0 of the backup power supply circuit 700, and a potential difference occurs between the gate drive circuit 900 and the backup power supply circuit 700. Accordingly, the operation of the gate drive circuit 900 becomes unstable. In contrast, according to the Fig. 4, the operations of the gate drive circuit 900 and the backup power supply circuit 700 are stabilized.

[0043] Accordingly, according to the first embodiment of the present invention, since the backup power supply circuit 700 is started by the gate power supply circuit 800 that supplies power to the gate drive circuit 900, a start-up circuit separately provided for starting the backup power supply circuit can be omitted. Accordingly, component costs can be reduced and a mounting area on the substrate can be reduced. [Second embodiment]

[0044] Fig. 6 is a diagram illustrating an overall configuration of the power conversion device 1000 according to a second embodiment. In the first embodiment, the example in which the reserve voltage is supplied from the reserve power supply circuit to the gate power supply circuit and the controller was described. In the second embodiment, however, the reserve voltage is supplied from the reserve power supply circuit to the controller, and a high voltage is supplied to the gate power supply circuit. In addition, in this case, the same sections as those in Fig. 1 according to the first embodiment are provided with the same reference numerals and their description is simplified equally.

[0045] For this purpose, 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 also arranged on the substrate 600. The substrate 600 is further divided into the high-voltage side 600H and the low-voltage side 600L by the insulation element 600a, and the backup power supply circuit 700 is divided into a high-voltage side 600H and a low-voltage side 600L by the insulation element 600a, such as a transformer. Furthermore, 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.

[0046] The backup power supply circuit 700 controls a 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 electrode busbar P and the negative electrode busbar N, generates a backup voltage in place of the low voltage supplied from the low-voltage power supply 4000, and supplies the backup voltage to the controller 910 via the diode D2. The backup power supply circuit 700 is further started by supplying a starting voltage output from the gate power supply circuit 800 via the backflow prevention diode D0 and the current limiting resistor R0.The backflow prevention diode D0 and the current limiting resistor R0 prevent the gate power supply circuit 800 from being overloaded and any overvoltages when the voltage of the backup power supply circuit 700 becomes abnormal.

[0047] Normally, a low voltage is supplied from the low-voltage power supply 4000 to the controller 910. However, when the low voltage is not supplied from the low-voltage power supply 4000 due to a fault, a backup voltage is provided instead of the low voltage from the backup power supply circuit 700. Details of the backup power supply circuit 700 will be described further below.

[0048] The gate power supply circuit 800 first generates a gate drive voltage for driving the gate drive circuit 900 based on the power supplied from the high-voltage power supply 2000 via the positive electrode bus P and the negative electrode bus N, and supplies the generated gate drive voltage to the gate drive circuit 900. The gate drive circuit 900 also drives the switching elements 411 and 421 based on the drive signal Pw output from the controller 910.

[0049] For this purpose, in the first embodiment, the emitter of the switching element 421 of each phase of the lower arm is connected to the ground in the gate drive circuit 900, but this is not the case in the present embodiment. Furthermore, the ground in the gate drive circuit 900 is also not connected to the ground in the backup power supply circuit 700.

[0050] The voltage conversion circuit 920 steps down the high voltage supplied from the high-voltage power supply 2000 via the positive electrode busbar P and the negative electrode busbar N to a predetermined operating voltage for operating the gate power supply circuit 800. Furthermore, after the operating voltage supplied from the voltage conversion circuit 920 exceeds a predetermined value, the gate power supply circuit 800 outputs the starting voltage to the backup power supply circuit 700 via the backflow prevention diode D0 and the current limiting resistor R0 to start the backup power supply circuit 700.

[0051] Fig. 7 also shows a diagram illustrating a detailed configuration of main units of the power conversion device 1000 according to the second embodiment.

[0052] In Fig. 7, the gate power supply circuit 800 and the gate drive circuit 900 corresponding to the lower-arm switching element 421 are illustrated, whereas the gate power supply circuit 800 and the gate drive circuit 900 corresponding to the upper-arm switching element 411 are not shown. In addition, in this case, the same sections as those in Fig. 2 according to the first embodiment are provided with the same reference numerals and their description is simplified in the same way.

[0053] The backup power supply circuit 700 includes a first power supply IC 710 and an isolation transformer TB1. Power is also supplied to one end of a primary winding Nb1 of the isolation transformer TB1 from the high-voltage power supply 2000 via the positive electrode busbar P. At the other end of the primary winding Nb1 of the isolation transformer TB1, the field-effect transistor FE1 is further connected to the ground GND0 of the first power supply IC 710 via the resistor R1. Furthermore, the ground GND0 is connected to the negative electrode busbar N.

[0054] The first power supply IC 710 is started when the starting voltage Va generated by the gate power supply circuit 800 is supplied to a power supply terminal Vcc via the backflow prevention diode D0 and the current limiting resistor R0. Subsequently, the switching of the field-effect transistor FE1 is controlled with a signal output from the signal terminal SW, and a reserve voltage Vb is generated by a flyback operation using a secondary winding Nb2, a diode, and a capacitor of the isolation transformer TB1. The reserve voltage Vb is also supplied to the controller 910.

[0055] The isolation transformer TB1 is further provided with the auxiliary winding Nbc, and a feedback voltage Vf1 is generated using the output voltage from the auxiliary winding Nbc. Furthermore, the feedback voltage Vf1 is supplied to the power supply terminal Vcc of the first power supply IC 710 via the diode, 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 such that a divided voltage of the feedback voltage Vf1 input to the feedback terminal FB becomes a predetermined target voltage.Accordingly, since the voltage of the feedback voltage Vf1 is set to a voltage higher than the starting voltage Va, the operation of the first power supply IC 710 continues similarly to the first embodiment by using the power from the feedback voltage Vf1 after starting the first power supply IC 710.

[0056] In the voltage conversion circuit 920, a series circuit of a field-effect transistor FE3 and a Zener diode Z3 is also connected between the positive electrode busbar P and the negative electrode busbar N. Then, a voltage from the positive electrode busbar P is input to the gate of the field-effect transistor FE3 via a resistor R3. In addition, a 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 IC 810 via the diode D3. The voltage conversion circuit 920 here converts a voltage from the high-voltage power supply 2000 into an operating voltage of the second power supply IC 810 of the gate power supply circuit 800.Further, an output from the connection point between the field effect transistor FE3 and the Zener diode Z3 of the voltage conversion circuit 920 is supplied to the gate power supply circuit 800 corresponding to the upper arm switching element 411 (not shown).

[0057] 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 started when the operating voltage supplied from the voltage conversion circuit 920 to the power supply terminal Vcc exceeds a predetermined value, performs switching control on the field-effect transistor FE2 with a signal output from the signal terminal SW, and generates a gate drive voltage through a flyback operation using the secondary winding Ng2 of the isolation transformer TG1, a diode, and a capacitor. For this purpose, three secondary windings Ng2 of the isolation transformer TG1 are also provided, corresponding to the three gate drive circuits GD1, GD2, and GD3, which drive the lower-arm switching element 421 and each generate a gate drive voltage.

[0058] Further, the isolation transformer TG1 is provided with the auxiliary winding Ngc, and the feedback voltage Vf2 generated using the output voltage from the auxiliary winding Ngc is divided and input to the feedback terminal FB of the second power supply IC 810. The second power supply IC 810 of the gate power supply circuit 800 performs switching control on the field-effect transistor FE2 such that the divided voltage of the feedback voltage Vf2 input to the feedback terminal FB becomes a predetermined target voltage after the second power supply IC 810 is started with the operating voltage supplied by the voltage conversion circuit 920 exceeding a predetermined value. Furthermore, the feedback voltage Vf2 is input to the power supply terminal Vcc of the second power supply IC 810 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 IC 810.

[0059] Since the voltage of the feedback voltage Vf2 is set to a voltage higher than the operating voltage from the voltage conversion circuit 920, the operation of the second power supply IC 810 continues using the power from the feedback voltage Vf2 after the second power supply IC 810 is started. Furthermore, 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 backflow prevention diode D0 and the current limiting resistor R0, and starts the backup power supply circuit 700. That is, the gate power supply circuit 800 generates the starting voltage Va and starts the backup power supply circuit 700 after the operating voltage supplied from the voltage conversion circuit 920 exceeds the predetermined value.

[0060] Gate drive circuit 900 also shows three gate drive circuits GD1, GD2, and GD3 that drive the lower-arm switching element 421. The drive signal Pw output from the controller 910 is input to the base of the switching element 421, and the switching element 421 is turned on and off to be driven. The three gate drive circuits that drive the upper-arm switching element 411 (not shown) also have a similar configuration.

[0061] Fig. 8(A) to Fig. 8(G) further illustrate timing charts illustrating operations of the backup power supply circuit 700 and the gate power supply circuit 800 according to the second embodiment. Fig. 8(A) illustrates a high voltage supplied by the high voltage power supply 2000, Fig. 8(B) illustrates an operating voltage of the second power supply IC 810 supplied from the voltage conversion circuit 920, Fig. Fig. 8(C) illustrates a signal output from the signal terminal SW of the second power supply IC 810, Fig. 8(D) illustrates the feedback voltage Vf2 generated by the gate power supply circuit 800, Fig. 8(E) illustrates a signal output from the signal terminal SW of the first power supply IC 710, Fig. 8(F) illustrates the feedback voltage Vf1 generated by the backup power supply circuit 700, and Fig. 8(G) illustrates the reserve voltage Vb generated by the reserve power supply circuit 700.

[0062] Now, a description will be given with reference to a diagram of a detailed configuration of main units of the power conversion device 1000 as shown in Fig. 7 illustrated.

[0063] When contactor 4001 is energized, a low voltage is initially supplied from low voltage power supply 4000, and controller 910 becomes operational. When contactor 2001 is energized, as shown in Fig. 8(A), a high voltage is supplied from the high-voltage power supply 2000 to the voltage conversion circuit 920. Accordingly, an output voltage of the voltage conversion circuit 920 gradually increases from 0 V to 12 V. The 12 V is to be understood as an example of the low voltage. Subsequently, when this voltage reaches the starting voltage vi of the second power supply IC 810 of the gate power supply circuit 800, the gate power supply circuit 800 is started, as shown in Fig. 8(C) illustrates.

[0064] When the gate power supply circuit 800 is started and the feedback voltage Vf2 becomes higher than the operating voltage vj of the first power supply IC 710 of the backup power supply circuit 700, as shown in Fig. 8(D), the first power supply IC 710 also starts the switching control operation as shown in Fig. 8(E). The feedback voltage Vf2 of 16 V is also to be understood as an example.

[0065] When the first power supply IC 710 starts operation and performs switching control on the field effect transistor FE1, the feedback voltage Vf1 is further generated as shown in Fig. 8(F). At this time, the feedback voltage Vf1 is controlled to a voltage higher than the starting voltage Va, for example, 17 V. Further, the backup power supply circuit 700 generates the backup voltage Vb as shown in Fig.8(G). Here, the reserve voltage Vb is, for example, 8 V. The contactor 2001 is turned on, and the reserve power supply circuit 700 enters the operating state after the time Tb. Thus, power is supplied from the high-voltage power supply 2000 to the reserve power supply circuit 700. Therefore, the reserve voltage Vb is supplied from the reserve power supply circuit 700 even when the low voltage is not supplied from the low-voltage power supply 4000 due to a fault.

[0066] Accordingly, according to the second embodiment of the present invention, since 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, a startup circuit separately provided for starting the backup power supply circuit can be omitted. Accordingly, component costs can be reduced, and a mounting area on the substrate can be reduced.

[0067] In the first embodiment described above, if the supply of the low voltage from the low-voltage power supply 4000 is stopped from the beginning due to a fault, the gate power supply circuit 800 cannot be started, and thus the backup power supply circuit 700 cannot be started. In contrast, in the second embodiment, even if the supply of the low voltage from the low-voltage power supply 4000 is stopped from the beginning due to a fault, the high voltage supplied from the high-voltage power supply 2000 can be converted by the voltage conversion circuit 920 to generate the operating voltage of the second power supply IC 810, so that the gate power supply circuit 800 can be started using the operating voltage.Subsequently, the backup power supply circuit 700 can also be started using the starting voltage Va (the feedback voltage Vf2) output from the started gate power supply circuit 800. Therefore, according to the second embodiment, the availability of the power conversion device 1000 can be further improved.

[0068] According to the embodiment described above, it is possible to achieve the following operational effects.

[0069] (1) The power conversion device 1000 includes: switching elements 411 and 42 connected in series with upper and lower arms; a gate drive circuit 900 configured to drive the switching elements 411 and 42; a controller 910 configured to operate with a predetermined low voltage supplied from a low-voltage power supply 4000 and to output a drive signal Pw for driving the switching elements 411 and 42 to the gate drive circuit 900; a gate power supply circuit 800 configured to generate a gate drive voltage for driving the gate drive circuit 900 and to supply the generated gate drive voltage to the gate drive circuit 900;and a backup power supply circuit 700 configured to control a current supplied from the high-voltage power supply 2000 to the primary winding of an isolation transformer TB1 to generate a backup voltage Vb instead of the low voltage, and to supply the generated backup voltage Vb to the controller 910. The backup power supply circuit 700 is further started with a starting voltage Va output from the gate power supply circuit 800. Accordingly, the starting circuit that starts the backup power supply circuit can be omitted.

[0070] The present invention is not limited to the above-described embodiments, and other forms considered within the scope of the technical ideas of the present invention are also within the scope of the present invention, as long as the features of the present invention are not impaired. Furthermore, the above-described embodiments can be combined. List of reference symbols 200 voltage detector 300 DC detector 400 inverter circuit 410 power module 411, 421 switching element 412, 422 diode 500 Output current detector 600 substrate 600a insulation element 600H high voltage side of the substrate 600L low voltage side of the substrate 700 reserve 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 Control 1000 power conversion device 2000 High-voltage power supply 2001 Schütz 3000 engine 4000 low-voltage power supply 4001 contactor TB1, TG1 isolation transformer FE1, FE2 field-effect transistor R1, R2 resistor Vcc power supply connection SW signal connection FB feedback connection Va starting voltage Vb reserve voltage D0 backflow prevention diode R0 current limiting resistor GND1, GND2, GND3 Ground P positive electrode busbar N negative electrode busbar Pw control signal QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] JP 2017-118815 A

[0003] JP 2015-159684 A

[0003]

Claims

[1] A power conversion device comprising: a switching element connected in series with upper and lower branches; a gate drive circuit configured to drive the switching element; a controller configured to operate with a predetermined low voltage supplied from a low-voltage power supply and to output a drive signal for driving the switching element to the gate drive circuit; a gate power supply circuit configured to generate a gate drive voltage for operating the gate drive circuit and to supply the generated gate drive voltage to the gate drive circuit; and a reserve power supply circuit configured to control a current supplied from a high-voltage power supply to a primary winding of an isolation transformer to generate a reserve voltage instead of the low voltage, and to supply the generated reserve voltage to the controller, wherein the backup power supply circuit is started with a starting voltage output from the gate power supply circuit. [2] The power conversion device according to claim 1, wherein the gate power supply circuit generates the gate drive voltage based on the low voltage and outputs the generated gate drive voltage as the starting voltage to the backup power supply circuit. [3] The power conversion device according to claim 2, wherein 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, wherein the gate power supply circuit generates the gate drive voltage and the backup power supply circuit starts 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, wherein a ground of the backup power supply circuit is connected to an emitter reference ground of the gate drive circuit, and the emitter reference ground is connected to a negative electrode of the high-voltage power supply via a bus bar. [6] The power conversion device according to claim 1, wherein the gate power supply circuit generates the gate drive voltage and the start voltage based on a predetermined high voltage supplied from the high voltage power supply, and outputs the generated start voltage to the backup power supply circuit. [7] The power conversion device according to claim 6, further comprising a voltage conversion circuit configured to convert the high voltage supplied from the high voltage power supply into an operating voltage of the gate power supply circuit, wherein 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, wherein the gate power supply circuit generates the starting voltage and the backup power supply circuit starts after the operating voltage supplied from the voltage conversion circuit exceeds a predetermined value. [9] The power conversion device according to claim 1, wherein 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 started by receiving the starting voltage output from the gate power supply circuit. [10] The power conversion device according to claim 9, wherein the starting voltage generated by the gate power supply circuit is supplied to a power supply terminal of the power supply IC via a backflow prevention diode and a current limiting resistor. [11] The power conversion device according to claim 10, wherein the backup power supply circuit generates a feedback voltage based on the current supplied by the high-voltage power supply to the primary winding of the isolation transformer, and the feedback voltage generated by the backup power supply circuit is supplied to the power supply terminal after the power supply IC is started by receiving the start voltage.

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