PERFORMANCE TAX DEVICE

Abstract

Power control device (10), comprising: a first smoothing capacitor (30) configured to smooth the output of a high-voltage battery (1) of a vehicle; a boost converter (40) configured to boost a voltage smoothed by the first smoothing capacitor (30); a second smoothing capacitor (50) configured to smooth the output of the boost converter (40); an inverter unit (60) to which a voltage smoothed by the second smoothing capacitor (50) is input; a gate control unit (80) configured to perform a discharge operation to discharge the first smoothing capacitor (30) and the second smoothing capacitor (50); a backup power supply unit (70A, 70B) connected to the first smoothing capacitor (30) or the second smoothing capacitor (50) and configured to supply power to the gate control unit (80); and an output voltage switching unit (100) configured to adjust the voltage of the backup power supply unit (70A, 70B) during normal operation to be equal to or lower than a voltage supplied to the gate control unit (80) from an auxiliary battery (3), and to switch the voltage of the backup power supply unit (70A, 70B) during discharge operation by the gate control unit (80) to be equal to or higher than the voltage supplied from the auxiliary battery (3).

Description

BACKGROUND OF THE INVENTION 1. Field of the invention

[0001] The present disclosure relates to a power control device. 2. Description of the background

[0002] A power control device installed in an electric or hybrid vehicle receives high voltage from a high-voltage battery, ranging from 200 to 400 V. This high voltage can be used by a motor-generator either as is or after being further stepped up. In this case, if charge (energy) remains in a capacitor (referred to below as a "smoothing capacitor") used to smooth the voltage in the power control device, an electric shock can occur. Specifically, this electric shock can occur during vehicle repair or inspection if a worker touches a high-voltage area. Similarly, in the event of a vehicle collision, this electric shock can occur if a driver, passenger, or rescuer touches a high-voltage area.Therefore, at the time of a collision and at the end of normal operation, the smoothing capacitor must discharge to have a voltage such that a person will not suffer an electric shock, even if they make contact.

[0003] As a conventional technology for addressing these problems, JP 5 333 348 B2, for example, discloses the following configuration: if, at the time of a collision or the like of a vehicle, an abnormality (open circuit or voltage reduction) is detected in a power line from an auxiliary battery supplying current to a discharge control unit for the smoothing capacitor, and an abnormality (open circuit or voltage reduction) is detected in a communication line for reporting the collision to the discharge control unit, current from outside is supplied to the discharge control unit by a backup power supply unit in such a way as to discharge charge stored in the capacitor.

[0004] Additionally, JP 2011-244625A discloses the following configuration: current required at least for discharge operation at the time of discharge is supplied by a backup power supply unit; current is constantly supplied to a discharge control unit in a state where a backup power supply unit Eb and a power source Es, such as a converter circuit or a DC power supply such as a battery, are arranged in parallel; and emergency power is supplied from the backup power supply unit Eb if a situation arises in which current cannot be supplied from the power source Es due to a certain interruption factor.

[0005] However, the number of times the auxiliary battery is charged / discharged increases with the configuration in which, as in JP 5 333 348 B2, output from the backup power supply unit is only used when an abnormality in the power line from the auxiliary battery occurs due to a collision or some interruption factor, and current from the auxiliary battery is used in a normal discharge operation. Additionally, in JP 2011 - 244 625 A, the problem arises that the time period for normal discharge increases proportionally to the increase in the capacitance of the smoothing capacitor, since current from the backup power supply unit is not used during a normal discharge operation.

[0006] A vehicle known from DE 11 2011 105 292 T5 generates tractive force by driving a motor-generator with a power control unit (PCU) using power stored in a power storage device mounted on it. As a function for discharging electrical charge remaining in a capacitor in the PCU, the vehicle can perform a motor-generator discharge, in which the discharge is carried out by supplying current to the motor-generator so that no torque is generated, and a PCU discharge, in which the discharge is carried out by generating a current supply loss at switching elements in the PCU. Upon detecting a collision of the vehicle, an HV electronic control unit (ECU) performs the PCU discharge with priority and performs the motor-generator discharge when the capacitor voltage is high.

[0007] DE 11 2013 007 438 T5 discloses an electrical storage device with a battery for a vehicle, in which an auxiliary battery, which serves as a main power supply for a control device, is used as a power source for supplying energy to the control device. An auxiliary power supply is also provided. If an abnormality occurs in the auxiliary battery, the power supply to the control device is switched from the auxiliary battery to the auxiliary power supply by a power supply switching device in order to operate the control device stably and to discharge the battery. Thus, the discharge can be stopped before the battery is over-discharged.

[0008] However, neither DE 11 2011 105 292 T5 nor DE 11 2013 007 438 T5 disclose a reserve power supply unit connected to a first smoothing capacitor or a second smoothing capacitor and supplying current to a gate control unit, and an output voltage switching unit which, during discharge operation by the gate control unit, switches the voltage of the reserve power supply unit so that it is equal to or higher than the voltage supplied from an auxiliary battery. SUMMARY OF THE INVENTION

[0009] The present disclosure has been made to solve the above problems and one objective of the present disclosure is to provide a current control device which contributes to a reduction in the number of times an auxiliary battery is charged / discharged and makes it possible to shorten the time period for discharging a smoothing capacitor.

[0010] A current control device 10 according to the present disclosure is a current control device which includes: a first smoothing capacitor 30 configured to smooth the output of a high-voltage battery 1 of a vehicle; a boost converter 40 configured to boost a voltage smoothed by the first smoothing capacitor 30; a second smoothing capacitor 50, which is configured to smooth the output of the boost converter 40; an inverter unit 60, to which a voltage smoothed by the second smoothing capacitor 50 is input; a gate control unit 80 configured to perform a discharge operation to discharge the first smoothing capacitor 30 and the second smoothing capacitor 50; a backup power supply unit 70A, 70B, which is connected to the first smoothing capacitor 30 or the second smoothing capacitor 50 and is configured to supply power to the gate control unit 80; and an output voltage switching unit 100, which is configured during normal operation to set a voltage of the reserve power supply unit 70A, 70B so that it is equal to or lower than a voltage supplied from an auxiliary battery 3 to the gate control unit 80, and during discharge operation by the gate control unit 80 to switch the voltage of the reserve power supply unit 70A, 70B so that it is equal to or higher than the voltage supplied from the auxiliary battery 3.

[0011] With the current control device according to the present disclosure, charged energy of the smoothing capacitor, which is arranged in a housing of the current control device, can be effectively discharged, thereby improving the reliability of the discharge operation.

[0012] Additionally, the current control device can contribute to a reduction in the number of charge / discharge cycles of the auxiliary battery, as the current supplied from the auxiliary battery is reduced by setting the output of the backup power supply unit at the time of discharge to a voltage no lower than the voltage from the auxiliary battery. Furthermore, the current control device can contribute to shortening the discharge period by utilizing the stored energy in the smoothed capacitors. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a block diagram of the entirety of a vehicle on which a current control device according to embodiment 1 is mounted; Fig. Figure 2 is a timing diagram showing the operation of the output by a backup power supply unit in Fig. 1 indicates; Fig. Figure 3 is a diagram showing a circuit configuration of an output voltage switching unit in Fig. 1 indicates; Fig. Figure 4 is a block diagram of the entirety of a vehicle on which a current control device according to embodiment 2 is mounted; Fig. 5 is a diagram showing a circuit configuration of the output voltage switching unit in Fig. 4 indicates; Fig. Figure 6 is a block diagram of the entire vehicle on which a current control device according to embodiment 3 is mounted; and Fig. Figure 7 is a diagram showing an example of hardware of a higher-rank ECU 6 and a microcomputer in the power control device 10 in embodiment 3. DETAILED DESCRIPTION OF THE PREFERRED EXECUTIONS OF THE INVENTION

[0013] Preferred embodiments of a current control device according to the present disclosure are described below with reference to the drawings. The same terms and corresponding components are designated by the same reference numerals, and a detailed description thereof is omitted. Similarly, in the following embodiment, the repeated description of components designated by the same reference numerals is omitted in the same manner. Design 1

[0014] Fig. Figure 1 is a block diagram of the entirety of a vehicle on which a current control device according to embodiment 1 is mounted.

[0015] The vehicle includes a high-voltage battery 1, a contactor 2, an auxiliary battery 3, a collision detection unit 4, a motor generator 5 and a current control device 10.

[0016] The high-voltage battery 1 is a rechargeable energy storage device and is implemented by a secondary battery that uses nickel-hydrogen, lithium-ion or the like.

[0017] The contactor 2 serves to establish a connection in order to send current from the high-voltage battery 1 to the current control device 10. If the collision detection unit 4 detects a collision, the contactor 2 is switched off, thus interrupting the current supply from the high-voltage battery 1.

[0018] The auxiliary battery 3 is a rechargeable energy storage device and is implemented by a lead-acid storage battery or the like.

[0019] When a vehicle collision is detected, the collision detection unit 4 reports a detected signal to a gate control unit 80 in the current control device 10, which is described later, and switches off the contactor 2. Methods for reporting from the collision detection unit 4 to the gate control unit 80 include a method of directly inputting a signal to the current control device 10 and a method of sending a command from a higher-order device, such as an ECU, to the current control device 10, as described later. Fig. 6 shown.

[0020] The motor-generator 5 is driven by the current control device 10, thereby generating the vehicle's drive torque. The motor-generator 5 generates energy when, for example, the vehicle is braked.

[0021] The current control device 10 comprises: an inverter unit 60 for driving the motor-generator 5; a step-up converter unit 110; the gate control unit 80, which performs discharge control; a backup power supply unit 70A, which supplies drive current to the gate control unit 80; and an output voltage switching unit 100, which switches an output voltage from the backup power supply unit 70A. These units are arranged in the same housing of the current control device 10.

[0022] The boost converter unit 110, which steps up a voltage from the high-voltage battery 1 to generate a voltage for the inverter unit 60, is composed of: a boost converter reactor 20; a first smoothing capacitor 30; and a boost converter 40 in which switching elements are arranged in series. The first smoothing capacitor 30 is a capacitor that smooths the voltage to reduce variations between the boost converter reactor 20 and the boost converter 40. The boost converter unit 110 supplies current from the high-voltage battery 1 to the inverter unit 60 to drive the motor-generator 5, either at a voltage that is unchanged from that of the supplied current or by converting the current to a boosted voltage.

[0023] A second smoothing capacitor 50 is a capacitor that performs smoothing in such a way that the variation between the voltage boosted by the step-up converter unit 110 and a voltage of the inverter unit 60 is reduced.

[0024] The inverter unit 60 converts a voltage output from the boost converter unit 110, smoothed by the second smoothing capacitor 50, to control the motor-generator 5. Specifically, the inverter unit 60 is a bridge circuit consisting of three-phase switching elements that converts the direct current sent from the boost converter unit 110 into three-phase alternating current. Additionally, the inverter unit 60 regenerates energy when, for example, the vehicle is braking.

[0025] The 70A reserve power supply unit is connected between the step-up converter unit 110 and the inverter unit 60 and, during normal operation, constantly outputs a lower voltage than the auxiliary battery 3. If the collision detection unit 4 detects a collision, the output voltage switching unit 100 switches the output voltage of the 70A reserve power supply unit to a higher voltage than the auxiliary battery 3. This switching of the output voltage efficiently consumes and discharges the energy stored in the high-voltage capacitors in the current control device 10, namely the second smoothing capacitor 50 and the first smoothing capacitor 30, even if current continues to be supplied from the auxiliary battery 3 at the time of the collision.

[0026] The gate control unit 80 receives a collision detection signal from the collision detection unit 4 and drives the inverter unit 60, thereby controlling the discharge of the first smoothing capacitor 30 and the second smoothing capacitor 50. The output voltage switching unit 100 switches the output voltage of the backup power supply unit 70A to a higher voltage than the voltage of the auxiliary battery 3 (in the drawing, dashed arrows indicate commands).

[0027] A first reverse-flow prevention diode 91 and a second reverse-flow prevention diode 92 are reverse-flow prevention diodes that ensure current is supplied from the backup power supply unit 70A and the auxiliary battery 3 to drive the gate control unit 80. During normal operation, since the output voltage from the backup power supply unit 70A is lower than the voltage from the auxiliary battery 3, the gate control unit 80 is driven by the current from the auxiliary battery 3. When a collision is detected, because the output voltage switching unit 100 switches so that the voltage from the backup power supply unit 70A becomes higher than the voltage from the auxiliary battery 3, the gate control unit 80 is driven by the current from the backup power supply unit 70A.

[0028] Fig. Figure 2 is a timing diagram for a plant located in Fig. 1. Current control device explained. The vertical axis indicates the on and off of operations or the input / output voltage states of corresponding components. The horizontal axis indicates the flow of time. The contactor 2, which was switched on at time t1, is switched off at time t4 as a result of a signal from the collision detection unit 4, which switches to an on state at time t3, thus interrupting the current supply from the high-voltage battery 1.The signal from the collision detection unit 4, which switches to the "on" state at time t3 when a collision is detected, is also input to the gate control unit 80. The output voltage switching unit 100 is switched on at time t5 in response to a command from the gate control unit 80, so that an output voltage VB1 of the reserve power supply unit 70A is switched to an output voltage VB2, which is not lower than a voltage VB of the auxiliary battery 3 (time t6). Accordingly, energy stored in the first smoothing capacitor 30 and the second smoothing capacitor 50 in the current control device 10 is discharged from the reserve power supply unit 70A, and the gate control unit 80 controls the inverter unit 60, thereby initiating a discharge operation (time t7).The discharge operation continues until the voltage drops to a level at which a person will not receive an electric shock, even if touched. The discharge operation is completed when the voltage drops to this level or lower.

[0029] In Fig. 2. The output of the output voltage switching unit 100 will be on after contactor 2 is switched from on to off. However, the output can be on before contactor 2 is switched off.

[0030] Additionally, a constant output from the 70A backup power supply unit is started at time t2 after contactor 2 is switched on at time t1. This facilitates prompt fault detection of voltage abnormalities in the 70A backup power supply unit.

[0031] In the reference to Fig. 1 and Fig. As described in section 2, the discharge operation is initiated when a collision is detected. However, the same discharge operation can be initiated if a communication interruption, an abnormality of one of the voltage sensors, or the like is detected at the end of a normal operation. The same applies to embodiments 2 and 3, which are described later.

[0032] Fig. Figure 3 is an example of circuit configurations for the 70A backup power supply unit and the 100A output voltage switching unit, which are shown in Fig. Figure 1 shows, for example, the 70A backup power supply unit as a basic flyback power supply circuit between the 110 boost converter unit and the 60 inverter unit, as shown in Figure 1. Fig. 1, connected and the current to be sent via lines of the 70A reserve power supply unit from a 200 power source Fig. 3 output. The connection is made such that current from the power source 200 is sent to the primary side of an isolation transformer 210, and a switching element 240 is switched on / off, so that the current is sent to the secondary side of the isolation transformer 210. A diode 220 and a smoothing capacitor 230 straighten and smooth the output from the isolation transformer 210. The smoothed voltage is divided by a feedback resistor unit 290, and the voltages obtained by the division are fed back to a DC / DC converter control circuit unit 250 after being isolated by an isolation circuit unit 270, thus determining an output voltage of the backup power supply unit 70A.The feedback resistor unit 290 has one or more types of settings, so that each of the voltages, which are subdivided for corresponding set output voltages, can be used as a feedback voltage. The feedback voltage is switched by a feedback voltage switching unit 280. The feedback voltage switching unit 280 is arranged at a stage downstream of the feedback resistor unit 290, but can also be arranged at a stage upstream of it.

[0033] At the time of a vehicle collision, the gate control unit 80, which has received a collision signal from the collision detection unit 4, causes the feedback voltage switching unit 280 to switch the output of the feedback voltage from the feedback resistor unit so that the output voltage of the reserve power supply unit 70A becomes higher than the voltage of the auxiliary battery 3. The feedback voltage switching unit 280 is implemented by a switching element such as a transistor or a MOSFET (metal-oxide-semiconductor field-effect transistor). The isolation circuit unit 270 is implemented by an insulating component such as an isolation amplifier IC or a photocoupler. The current source 200 can be connected between the high-voltage battery 1 and the boost converter unit 110, as shown in Fig. 4, arranged as will be described later.

[0034] In the current control device described above in embodiment 1, the energy of the smoothing capacitor arranged in the housing can be effectively discharged, and thus a person does not suffer an electric shock not only at the time of any collisions, but also at the end of normal operation, even if the housing is opened and the inside of it is touched, thereby sufficiently improving reliability.

[0035] Additionally, a current control device may be provided which contributes to a reduction in the number of times the auxiliary battery is charged / discharged, as the current supplied from the auxiliary battery is reduced by setting the output of the backup power supply unit at the time of discharge to a voltage lower than the voltage from the auxiliary battery, and may contribute to shortening a discharge time period by using the charged energy of the smoothing capacitors in the housing.

[0036] Furthermore, it is possible to promptly detect an abnormality of the backup power supply unit by means of the constant output from the backup power supply unit, which is carried out in a state where the output is switched by the output voltage switching unit to have a voltage level not higher than the voltage level of the auxiliary battery at a time other than the time of discharge operation. Design 2

[0037] Fig. Figure 4 is a block diagram of the entire vehicle in which a current control device according to embodiment 2 is mounted. The configuration and name of each component are the same as those in Figure 4. Fig. 1. However, an area to which a backup power supply unit 70B is connected and a location where discharge control is carried out are different from those in Fig. 1. In Fig. 1. The reserve power supply unit 70A is connected between the step-up converter unit 110 and the inverter unit 60, while in Fig. 4. The backup power supply unit 70B is connected between the high-voltage battery 1 and the boost converter unit 110. Additionally, discharge control is performed by the boost converter 40. During discharge operation, such as in the event of a collision, a voltage generated by the backup power supply unit 70B from the energy of the first smoothing capacitor 30 is supplied to the gate control unit 80, and discharge control is performed by the boost converter unit 110. However, since the first smoothing capacitor 30 has a smaller capacitance than the second smoothing capacitor 50, it is predicted that the energy of the first smoothing capacitor 30 will be depleted before the second smoothing capacitor 50 is discharged. If the energy is depleted, output cannot be provided from the backup power supply unit 70B.Thus, the energy of the second smoothing capacitor 50 is stepped down using the switching elements of the boost converter 40 and supplied to the backup power supply unit 70B before the energy of the first smoothing capacitor 30 is depleted. This ensures a stable output from the backup power supply unit 70B until the discharge operation is complete.

[0038] Fig. 5 is a diagram showing a circuit configuration of the in Fig. The output voltage switching unit 100 shown in Figure 4 is the same basic flyback power supply circuit as the one in Figure 4. Fig. 3, but differs in that each feedback voltage is adjusted by applying a voltage to a low-voltage ground (GND) of the isolation circuit unit 270. During normal operation, in which no discharge operation is performed, the potential of the low-voltage ground (GND) of the isolation circuit unit is set to zero, so that the output voltage from the backup power supply unit 70B is equal to or lower than the voltage of the auxiliary battery 3. When the discharge operation command is issued from the gate control unit 80, the output of a GND level shifter 310 reduces the feedback voltage to the isolation circuit unit 270 by applying a positive voltage not lower than the GND voltage but not higher than the output voltage from the feedback resistor unit 300.The DC / DC converter control circuit unit 250, which has the reduced feedback voltage, performs control to increase the output voltage of the backup power supply unit 70B so that the level of the feedback voltage reaches that of a set voltage, and a voltage higher than that of the auxiliary battery 3 is supplied from the backup power supply unit 70B to the gate control unit 80.

[0039] The current control device in embodiment 2, as described above, exhibits the following effects in addition to the effect in embodiment 1: a breakdown voltage can be reduced, thus enabling the circuits to be configured at lower cost, and the output of the backup power supply unit can be supplied stably until the discharge operation is complete. embodiment 3

[0040] Fig. Figure 6 is a block diagram of the entire vehicle in which a current control device according to embodiment 3 is mounted. A high-order ECU (engine control unit) is used instead of the collision detection unit 4 in the Fig. The high-order ECU 6 is connected to the current control device 10 as shown in the block diagram. It includes a microcontroller for outputting drive torque, a discharge command, and other higher-order commands. At the time of collision, the high-order ECU 6 detects the collision and communicates with the current control device 10, causing a microcomputer (not shown) in the current control device 10 to drive the gate control unit 80. Alternatively, at the end of the drive, a discharge command is communicated from the high-order ECU 6 to the current control device 10, causing the microcomputer in the current control device 10 to drive the gate control unit 80.

[0041] Fig.Figure 7 shows an example of the hardware of a high-order ECU 6 and the microcomputer in the current control device 10. The hardware consists of a processor 1000 and a memory unit 2000. Although not shown, the memory unit includes a volatile memory unit, such as random access memory, and a non-volatile auxiliary memory unit, such as flash memory. Alternatively, the memory unit could include a hard disk instead of flash memory as the auxiliary memory unit. The processor 1000 executes a program input from the memory unit 2000, which, for example, causes the high-order ECU 6 to detect a collision and communicate with the current control device as described above. In this case, the program is input from the auxiliary memory unit to the processor 1000 via the volatile memory unit.Additionally, the processor can output 1000 data items, such as a calculation result, to the volatile memory unit of the memory unit 2000, or it can back up the data in the auxiliary memory unit via the volatile memory unit.

[0042] The current control device in embodiment 3, as described above, exhibits the following effects in addition to the effects in embodiment 1: by using the high-order ECU, detection of an event other than a collision can also be easily enabled, meaning that versatility can be improved and the circuit scale can be reduced. DESCRIPTION OF REFERENCE MARKS 1 high-voltage battery 2 Contactor 3 Auxiliary batteries 4 collision detection unit 5 Motor generator 6 High-order ECU 10 Current control device 20 Up-converter reactors 30 Smoothing capacitor 40 Upward Converters 50 Second smoothing capacitor 60 Inverter unit 70A, 70B, backup power supply unit 80 gate control unit 91 First backflow preventer diode 92 Second backflow preventer diode 100 Output voltage switching unit 110 Up-converter unit 200 power source 210 Isolation transformer 220 diode 230 smoothing capacitor 240 switching element 250 DC / DC converter control circuit unit 270 Isolation circuit unit 280 Feedback voltage switching unit 290, 300 feedback resistor unit 310 GND level conversion unit

Claims

[1] Power control device (10), comprising: a first smoothing capacitor (30) configured to smooth the output of a high-voltage battery (1) of a vehicle; a boost converter (40) configured to boost a voltage smoothed by the first smoothing capacitor (30); a second smoothing capacitor (50) configured to smooth the output of the boost converter (40); an inverter unit (60) to which a voltage smoothed by the second smoothing capacitor (50) is input; a gate control unit (80) configured to perform a discharge operation to discharge the first smoothing capacitor (30) and the second smoothing capacitor (50); a backup power supply unit (70A, 70B) connected to the first smoothing capacitor (30) or the second smoothing capacitor (50) and configured to supply power to the gate control unit (80); and an output voltage switching unit (100) configured to adjust the voltage of the backup power supply unit (70A, 70B) during normal operation to be equal to or lower than a voltage supplied to the gate control unit (80) from an auxiliary battery (3), and to switch the voltage of the backup power supply unit (70A, 70B) during discharge operation by the gate control unit (80) to be equal to or higher than the voltage supplied from the auxiliary battery (3). [2] Current control device (10) according to claim 1, wherein the discharge operation is started by the gate control unit (80) when a collision is detected. [3] Current control device (10) according to claim 1 or 2, wherein the reserve power supply unit (70A) is connected between the boost converter (40) and the inverter unit (60), and the gate control unit (80) controls the inverter unit (60), thereby carrying out the discharge operation. [4] Current control device (10) according to claim 1 or 2, wherein the backup power supply unit (70B) is connected between the high-voltage battery (1) and the boost converter (40), and the gate control unit (80) controls the boost converter (40), thereby carrying out the discharge operation. [5] Current control device (10) according to claim 4, wherein when a voltage of the first smoothing capacitor (30) becomes equal to or lower than an operating current supply voltage of the reserve power supply unit (70B) during discharge operation, energy is supplied to the second smoothing capacitor (50) after step-down. [6] Current control device (10) according to any one of claims 1 to 5, wherein the reserve power supply unit (70A, 70B) supplies current to the gate control unit (80) from a time at which current is supplied from the high voltage battery (1).

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