JP5187152B2 - Vehicle power supply system and vehicle - Google Patents

Description

  The present invention relates to a vehicle power supply system and a vehicle, and more particularly to a control technology for a vehicle power supply system that includes a plurality of power storage devices and a charging device for charging the power storage devices.

  In recent years, vehicles such as electric vehicles, hybrid vehicles, and fuel cell vehicles have been developed and put into practical use as environment-friendly vehicles. These vehicles are generally equipped with an electric motor that generates vehicle driving force and a power supply system for supplying driving electric power to the electric motor. The power supply system includes a power storage device.

  A configuration has been proposed in which a power storage device mounted on these vehicles is charged by a power source outside the vehicle (hereinafter also referred to as “external power source”). For example, Japanese Patent Laying-Open No. 2008-109840 (Patent Document 1) discloses a power supply system in which a plurality of power storage devices (batteries) are connected in parallel. The power supply system disclosed in Patent Document 1 includes a voltage converter (converter) as a charge / discharge adjustment device for each power storage device (battery).

Patent Document 1 further discloses a power supply device including a main power storage device and a plurality of sub power storage devices. The power supply device includes a converter corresponding to the main power storage device and a converter shared by the plurality of sub power storage devices.
JP 2008-109840 A

  2. Description of the Related Art Generally, a vehicle includes auxiliary equipment such as lighting, and an auxiliary battery for supplying power to the auxiliary equipment. When the power stored in the auxiliary battery is consumed by the operation of the auxiliary machine, the auxiliary battery is charged. As a result, the auxiliary battery can be prevented from rising.

  In addition, when charging a plurality of power storage devices mounted on a vehicle with an external power source, a method of charging each power storage device while sequentially switching power storage devices to be charged can be considered. When a plurality of power storage devices are charged at the same time, two power storage devices having different voltages may be short-circuited. In this case, a short-circuit current may flow from the high-voltage power storage device to the low-voltage power storage device. Such problems can be avoided by sequentially switching the power storage devices to be charged.

  Here, the auxiliary battery may continue to supply power to the auxiliary machine while charging a plurality of power storage devices mounted on the vehicle. In order to charge the auxiliary battery, it is conceivable to connect at least one of the plurality of power storage devices to the auxiliary battery. When the power storage device is charged by an external power source, the auxiliary battery is also charged at the same time.

  However, when another power storage device is charged, the power of the power storage device connected to the auxiliary battery is consumed to operate the auxiliary device. Therefore, it is considered that the remaining capacity of the power storage device connected to the auxiliary battery decreases while the other power storage device is charged.

  On the other hand, when the power supply from the power storage device to the auxiliary machine is stopped, the auxiliary machine consumes the electric power stored in the auxiliary battery. However, the capacity of the auxiliary battery is smaller than the capacity of the power storage device driven by the vehicle. Therefore, the auxiliary battery may be increased. Japanese Patent Application Laid-Open No. 2008-109840 (Patent Document 1) does not specifically show an auxiliary device of a vehicle, and therefore does not show a charging method for a plurality of power storage devices in consideration of the operation of the auxiliary device.

  An object of the present invention is to mount a power supply system for a vehicle that can charge each power storage device so that sufficient power can be stored in a plurality of power storage devices for driving a vehicle while preventing an auxiliary battery from rising, and the power supply system thereof Is to provide a vehicle.

  In summary, the present invention is a power supply system for a vehicle, which includes first and second power storage devices, a first power line, a second power line, a first connection unit, and a second connection unit. A voltage conversion device, a third power storage device, a charging device, and a control device. The first power line is provided corresponding to the first power storage device. The second power line is provided corresponding to the second power storage device. The first connection unit is configured to be capable of electrical connection and disconnection between the first power storage device and the first power line. The second connection unit is configured to be capable of electrical connection and disconnection between the second power storage device and the second power line. The voltage conversion device is connected between the first power line and the auxiliary device, and converts the voltage of power supplied from the first power storage device through the first connection portion and the first power line to the auxiliary device. The voltage is converted to a predetermined voltage for operation. The third power storage device is connected to the voltage conversion device in parallel with the auxiliary machine and accumulates electric power supplied from the voltage conversion device. The charging device is connected to the first and second power lines and charges the first and second power storage devices with an external power source outside the vehicle. The control device controls the first and second connection units and the charging device. The control device sets the second connection portion to a conductive state and charges the second power storage device, and controls the charging device so that power from the external power source is supplied to the second power line. The connection part 1 is set to a conductive state, and the operation of the voltage converter is continued.

  Preferably, the control device charges the first power storage device prior to charging the second power storage device, and the remaining capacity of the first power storage device reaches a predetermined value after completion of charging of the second power storage device. The first and second connecting portions and the charging device are controlled so that the first power storage device is charged up to.

  Preferably, the control device sets the first and second connection portions to a conductive state and a non-conductive state, respectively, and supplies power from the external power source to the first power line when charging the first power storage device. To control the charging device.

  Preferably, the power supply system further includes a leakage detector connected directly to the first power storage device. The control device determines whether or not there is a leakage in the power supply system based on the detection result of the leakage detector during charging of the first storage device and charging of the second storage device.

Preferably, the predetermined voltage is supplied to the control device as an operating voltage of the control device.
Preferably, the power supply system further includes a third power line. The charging device includes a first power conversion device, a second power conversion device, and a charger. The first power conversion device is connected to the first and third power lines and configured to be capable of bidirectional power conversion. The second power conversion device is connected to the second and third power lines and configured to be capable of bidirectional power conversion. The charger is configured to be able to output power supplied from an external power source to the second power line.

  Preferably, each of the first and second power conversion devices includes a power semiconductor switching element and a diode element. The power semiconductor switching element is inserted and connected to a current path between the corresponding power line and the third power line among the first and second power lines. The diode element is connected in parallel with the power semiconductor switching element, with the direction from the corresponding power line toward the third power line as the forward direction. When the power supplied from the external power source is output to the first power line via the charger, the control device sets each of the power semiconductor switching elements of the first and second power converters to a conductive state. On the other hand, when the power supplied from the external power source via the charger is output to the second power line, the power semiconductor switching elements of the first and second power converters are set in a non-conductive state. To do.

  When the other situation of this invention is followed, it is a vehicle, Comprising: The vehicle power supply system in any one of the above-mentioned, and an auxiliary machine are provided.

  According to the present invention, the power storage device can be charged so that sufficient power can be stored in the power storage device for driving the vehicle while preventing the auxiliary battery from rising.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals and description thereof will not be repeated.

  FIG. 1 is an overall block diagram of a hybrid vehicle shown as an example of a vehicle equipped with a power supply system according to an embodiment of the present invention.

  Referring to FIG. 1, hybrid vehicle 1000 includes an engine 2, motor generators MG <b> 1 and MG <b> 2, a power split mechanism 4, and wheels 6. Hybrid vehicle 1000 includes main power storage device BA, sub power storage devices BB1 and BB2, converters 10, 12, and 14, capacitor C, inverters 20 and 22, auxiliary machine 16, auxiliary battery SB, The ECU 30 further includes positive electrode lines PL1, PL2, PL3, and PL4, and a negative electrode line NL. The hybrid vehicle 1000 includes a voltage sensor 42, 44, 46, 48, a current sensor 52, 54, 56, a temperature sensor 62, 64, 66, a connection part 72, 74, 76, and a leakage detector 80. , Display device 90, charger 240, and inlet 250.

  Power supply system of the present embodiment includes main power storage device BA, sub power storage devices BB1 and BB2, auxiliary battery SB, connection portions 72, 74, and 76, converters 10, 12, and 14, and positive lines PL1 to PL1. PL4, negative electrode line NL, leakage detector 80, charger 240, inlet 250, and ECU 30 are included.

  Main power storage device BA corresponds to the “first power storage device” of the present invention. At least one of the sub power storage devices BB1 and BB2 corresponds to the “second power storage device” of the present invention. Auxiliary battery SB corresponds to “third power storage device” of the present invention.

  The positive lines PL1 to PL3 correspond to the “first power line”, “second power line”, and “third power line” of the present invention, respectively. The connecting portion 72 corresponds to the “first connecting portion” of the present invention. At least one of the connection portions 74 and 76 corresponds to a “second connection portion” of the present invention. The converter 14 corresponds to the “voltage converter” of the present invention.

  Converters 10, 12, charger 240 and inlet 250 constitute a “charging device” of the present invention. Furthermore, converters 10 and 12 correspond to “first power conversion device” and “second power conversion device” of the present invention, respectively. The charger 240 corresponds to the “charger” of the present invention. The ECU 30 corresponds to the “control device” of the present invention. The leak detector 80 corresponds to the “leak detector” of the present invention.

  Hybrid vehicle 1000 travels using engine 2 and motor generator MG2 as power sources. Power split device 4 is coupled to engine 2 and motor generators MG1, MG2, and distributes power between them. Power split device 4 is composed of, for example, a planetary gear mechanism having three rotation shafts of a sun gear, a carrier, and a ring gear, and these three rotation shafts are connected to the rotation shafts of engine 2 and motor generators MG1, MG2, respectively. It is noted that engine 2 and motor generators MG1 and MG2 can be mechanically connected to power split mechanism 4 by making the rotor of motor generator MG1 hollow and passing the crankshaft of engine 2 through the center thereof. The rotation shaft of motor generator MG2 is coupled to wheel 6 by a reduction gear or a differential gear (not shown). Motor generator MG <b> 1 is incorporated in hybrid vehicle 1000 as operating as a generator driven by engine 2 and operating as an electric motor that can start engine 2. Motor generator MG2 is incorporated in hybrid vehicle 1000 as an electric motor that drives wheels 6.

  Engine 2 can run hybrid vehicle 1000 in parallel with or only by motor generator MG2 by burning fuel such as gasoline.

  Each of main power storage device BA and sub power storage devices BB1 and BB2 is a chargeable / dischargeable power storage device, and is composed of, for example, a secondary battery such as nickel metal hydride or lithium ion. A large capacity capacitor may be used for at least one of main power storage device BA and sub power storage devices BB1 and BB2.

  Main power storage device BA supplies power to converter 10 and is charged by converter 10 during power regeneration. Sub power storage devices BB1 and BB2 supply power to converter 12 and are charged by converter 12 during power regeneration. Sub power storage devices BB1 and BB2 are selectively connected to converter 12 by connecting portions 74 and 76.

  One of sub power storage devices BB1 and BB2 (hereinafter referred to as sub power storage device BB) and main power storage device BA are, for example, electric loads (inverter 22 and motor) connected to positive electrode line PL3 and negative electrode line NL through simultaneous use. Each dischargeable capacity is set so that the maximum power allowed for the generator MG2) can be output. As a result, traveling at maximum power is possible in EV (Electric Vehicle) traveling without using the engine 2. If the power storage state of the power storage device in use of sub power storage devices BB1 and BB2 deteriorates, the power storage device connected to converter 12 may be replaced and further run. When the power stored in the sub power storage devices BB1 and BB2 is consumed, the engine 2 is used in addition to the main power storage device BA, so that the maximum power can be traveled without using the sub power storage devices BB1 and BB2. can do.

  Further, with such a configuration, since converter 12 is shared by a plurality of sub power storage devices, the number of converters need not be increased by the number of sub power storage devices. In order to further extend the EV travel distance, a power storage device may be added in parallel to the sub power storage devices BB1 and BB2. That is, in this embodiment, the number of sub power storage devices is two, but the number is not limited to this number.

  Connection unit 72 is provided between main power storage device BA and positive electrode line PL1 and negative electrode line NL. Connection unit 72 is controlled to be in a conductive state (ON) / non-conductive state (OFF) in accordance with signal CN1 provided from ECU 30. When connection unit 72 is turned on, main power storage device BA is connected to positive electrode line PL1 and negative electrode line NL. On the other hand, when connection portion 72 is turned off, main power storage device BA is disconnected from positive electrode line PL1 and negative electrode line NL.

  Connection unit 74 is provided between sub power storage device BB1, and positive electrode line PL2 and negative electrode line NL. Connection unit 74 is in a conductive state or a non-conductive state in accordance with signal CN2. Thereby, connecting portion 74 performs electrical connection and disconnection between sub power storage device BB1, positive electrode line PL2, and negative electrode line NL.

  Connection portion 76 is provided between sub power storage device BB2, and positive electrode line PL2 and negative electrode line NL. Connection unit 76 enters either a conductive state or a non-conductive state according to signal CN3. Thereby, connecting portion 76 performs electrical connection and disconnection between sub power storage device BB2, positive electrode line PL2, and negative electrode line NL.

  Converter 10 is connected to positive electrode line PL1 and negative electrode line NL. Converter 10 boosts the voltage from main power storage device BA based on signal PWC1 from ECU 30, and outputs the boosted voltage to positive line PL3. Converter 10 steps down the regenerative power supplied from inverters 20 and 22 via positive line PL3 to the voltage level of main power storage device BA based on signal PWC1, and charges main power storage device BA. Furthermore, converter 10 stops the switching operation when it receives shutdown signal SD1 from ECU 30. Furthermore, when converter 10 receives upper arm on signal UA1 from ECU 30, converter 10 fixes an upper arm and a lower arm (described later) included in converter 10 to an on state and an off state, respectively.

  Converter 12 is connected to positive electrode line PL2 and negative electrode line NL. Converter 12 boosts the voltage of sub power storage device BB based on signal PWC2 from ECU 30, and outputs the boosted voltage to positive line PL3. Converter 12 steps down the regenerative power supplied from inverters 20 and 22 via positive line PL3 to the voltage level of sub power storage device BB based on signal PWC2, and charges sub power storage device BB. Furthermore, converter 12 stops the switching operation when it receives shutdown signal SD2 from ECU 30. Furthermore, when converter 12 receives upper arm on signal UA2 from ECU 30, converter 12 fixes an upper arm and a lower arm (described later) included in converter 12 to an on state and an off state, respectively.

  Capacitor C is connected between positive electrode line PL3 and negative electrode line NL, and smoothes voltage fluctuations between positive electrode line PL3 and negative electrode line NL.

  Inverter 20 converts a DC voltage from positive line PL3 into a three-phase AC voltage based on signal PWI1 from ECU 30 during powering operation of motor generator MG1, and outputs the converted AC voltage to motor generator MG1. In addition, when power is generated by motor generator MG1, inverter 20 converts the three-phase AC voltage generated by motor generator MG1 using the power of engine 2 into a DC voltage based on signal PWI1, and the converted DC voltage is converted into a DC voltage. Output to the positive line PL3.

  Inverter 22 converts the DC voltage from positive line PL3 into a three-phase AC voltage based on signal PWI2 from ECU 30, and outputs the converted AC voltage to motor generator MG2. In addition, inverter 22 converts the three-phase AC voltage generated by motor generator MG2 by receiving the rotational force from wheel 6 during regenerative braking of the vehicle into a DC voltage based on signal PWI2, and the converted DC voltage is positively connected. Output to line PL3.

  Each of motor generators MG1 and MG2 is a three-phase AC rotating electric machine, for example, a three-phase AC synchronous motor generator. Motor generator MG <b> 1 is regeneratively driven by inverter 20, and outputs a three-phase AC voltage generated using the power of engine 2 to inverter 20. Motor generator MG1 is driven by power by inverter 20 when engine 2 is started, and cranks engine 2.

  Motor generator MG2 is driven by inverter 22 to generate a driving force for driving the vehicle. Motor generator MG <b> 2 is regeneratively driven by inverter 22 during regenerative braking of the vehicle, and outputs a three-phase AC voltage generated using the rotational force received from wheels 6 to inverter 22.

  Voltage sensor 42 detects voltage VA of main power storage device BA and outputs it to ECU 30. Current sensor 52 detects current IA input / output from main power storage device BA to converter 10 and outputs the detected current IA to ECU 30. Temperature sensor 62 detects temperature TA of main power storage device BA and outputs it to ECU 30.

  Voltage sensors 44 and 46 detect voltage VB1 of sub power storage device BB1 and VB2 of sub power storage device BB2, respectively, and output them to ECU 30. Current sensors 54 and 56 detect current IB1 input / output to / from converter 12 from sub power storage device BB1 and current IB2 input / output from sub power storage device BB2 to converter 12, and output them to ECU 30. Temperature sensors 64 and 66 detect temperature TB1 of sub power storage device BB1 and temperature TB2 of sub power storage device BB2, respectively, and output them to ECU 30.

  The voltage sensor 48 detects the voltage between terminals of the capacitor C (voltage VH) and outputs it to the ECU 30.

  Specifically, converter 14 is a DC / DC converter, and reduces the DC voltage of positive line PL1 in accordance with signal PWC3 from ECU 30. Positive line PL4 is connected to the output side of converter 14, and auxiliary machine 16 and auxiliary battery SB are connected in parallel to positive line PL4. The output voltage from the converter 14 is supplied to the auxiliary machine 16 and the auxiliary battery SB, whereby the auxiliary machine 16 operates and the auxiliary battery SB is charged.

  The auxiliary machine 16 is, for example, a headlight, a watch, an audio device, or the like, but the type is not particularly limited. The auxiliary battery SB is a chargeable / dischargeable power storage device, for example, a lead storage battery. Auxiliary battery SB is charged by the DC voltage from converter 14, and discharged by supplying driving power to auxiliary machine 16. Further, the voltage VD of the auxiliary battery SB is supplied to the ECU 30. As a result, the ECU 30 operates.

  Charger 240 and inlet 250 are provided to charge main power storage device BA and sub power storage devices BB1 and BB2 by a power supply external to hybrid vehicle 1000. Electric power supplied from a power source (external power source) outside the vehicle is output between positive line PL2 and negative line NL via inlet 250 and charger 240. Charger 240 operates and stops in response to signal CHG from ECU 30.

  The ECU 30 generates and outputs signals CN1 to CN3 for controlling the connecting portions 72, 74, and 76, respectively. Further, ECU 30 generates signals PWC 1, SD 1, UA 1 for controlling converter 10, and outputs any of these signals to converter 10. ECU 30 also generates signals PWC 2, SD 2, UA 2 for controlling converter 12, and outputs any of these signals to converter 12.

  Further, ECU 30 generates signals PWI1 and PWI2 for driving inverters 20 and 22, respectively, and outputs the generated signals PWI1 and PWI2 to inverters 20 and 22, respectively. Further, ECU 30 generates a signal PWC 3 for controlling converter 14 and outputs the signal to converter 14. Further, the ECU 30 generates a signal CHG for controlling the charger 240 and outputs the signal CHG to the charger 240.

  Electric leakage detector 80 detects electric leakage in the vehicle system shown in FIG. If leakage occurs due to a decrease in insulation resistance during charging of main power storage device BA and sub power storage devices BB1, BB2, leakage detector 80 outputs a signal indicating that leakage has occurred to ECU 30. ECU 30 sets all of connection portions 72, 74, and 76 in a non-conductive state in accordance with a signal from leakage detector 80 and stops converters 10, 12 and charger 240.

  The display device 90 displays various information under the control of the ECU 30. For example, when ECU 30 receives a command IGON for starting the vehicle system shown in FIG. 1, information indicating that charging of main power storage device BA and sub power storage devices BB1 and BB2 has been completed, the remaining capacity of each power storage device And the like are displayed on the display device 90. When charging is interrupted due to leakage during charging of main power storage device BA and sub power storage devices BB1 and BB2, ECU 30 displays information indicating that charging has been interrupted in response to command IGON. 90.

  Hybrid vehicle 1000 is configured such that main power storage device BA and sub power storage devices BB1 and BB2 can be charged by a power supply external to the vehicle. During charging of each power storage device, ECU 30 controls connection units 72 to 76, converters 10 and 12, and charger 240.

  FIG. 2 is a circuit diagram showing a configuration of converters 10 and 12 and connecting portions 72 to 76 shown in FIG.

  Referring to FIG. 2, converter 10 includes power semiconductor switching elements Q1, Q2, diodes D1, D2, a reactor L1, and a capacitor C1.

  In the present embodiment, an IGBT (Insulated Gate Bipolar Transistor) is applied as a power semiconductor switching element (hereinafter also simply referred to as “switching element”), but can be controlled on / off by a control signal. Any switching element can be applied. For example, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or a bipolar transistor can be applied.

  Switching elements Q1, Q2 are connected in series between positive electrode line PL3 and negative electrode line NL. Diodes D1 and D2 are connected in antiparallel to switching elements Q1 and Q2, respectively. Reactor L1 has one end connected to a connection node of switching elements Q1 and Q2, and the other end connected to positive line PL1. Capacitor C1 is connected to positive electrode line PL1 and negative electrode line NL.

  Converter 12 has the same configuration as converter 10. In the configuration of converter 10, switching elements Q1, Q2 are replaced with switching elements Q3, Q4, diodes D1, D2 are replaced with diodes D3, D4, respectively, and reactor L1, capacitor C1, and positive line PL1 are reactor L2, capacitor C2, and The configuration replaced with positive electrode line PL <b> 2 corresponds to the configuration of converter 12.

  Switching elements Q1 and Q3 correspond to the upper arms of converters 10 and 12, and switching elements Q2 and Q4 correspond to the lower arms of converters 10 and 12.

  Converters 10 and 12 are formed of a chopper circuit. Converter 10 (12) boosts the voltage of positive line PL1 (PL2) using reactor L1 (L2) based on signal PWC1 (PWC2) from ECU 30 (FIG. 1), and the boosted voltage is increased. Output to the positive line PL3. Specifically, by controlling the on / off period ratio (duty) of switching element Q1 (Q3) and / or switching element Q2 (Q4), the output voltage from main power storage device BA and sub power storage device BB is boosted. The ratio can be controlled.

  On the other hand, converter 10 (12) lowers the voltage of positive line PL3 based on signal PWC1 (PWC2) from ECU 30 (not shown), and outputs the reduced voltage to positive line PL1 (PL2). Specifically, the voltage step-down ratio of positive line PL3 can be controlled by controlling the on / off period ratio (duty) of switching element Q1 (Q3) and / or switching element Q2 (Q4).

  Connection unit 72 includes system main relay SRB1 connected between the positive electrode of main power storage device BA and positive electrode line PL1, and system main relay SRG1 connected between the negative electrode of main power storage device BA and negative electrode line NL. System main relay SRP1 and limiting resistor RA connected in series between the negative electrode of main power storage device BA and negative electrode line NL and provided in parallel with system main relay SRG1. System main relays SRB1, SRP1, and SRG1 are controlled to be in a conductive state (ON) / non-conductive state (OFF) by a signal CN1 provided from ECU 30.

  The connection parts 74 and 76 have the same configuration as the connection part 72 described above. In other words, in the configuration of connection portion 72 described above, main power storage device BA is replaced with sub power storage device BB1, system main relays SRB1, SRP1, and SRG1 are replaced with system main relays SRB2, SRP2, and SRG2, respectively, and limiting resistor RA is limited resistor RB1. The configuration replaced with corresponds to the configuration of the connecting portion 74. Each system main relay included in connection unit 74 is controlled to be in a conductive state and a non-conductive state by a signal CN2 from ECU 30.

  In the configuration of connection portion 72 described above, main power storage device BA is replaced with sub power storage device BB2, system main relays SRB1, SRP1, and SRG1 are replaced with system main relays SRB3, SRP3, and SRG3, respectively, and limiting resistance RA is limited resistance RB2. The configuration replaced with corresponds to the configuration of the connecting portion 76. Each system main relay included in connection unit 76 is controlled to be in a conductive state and a non-conductive state in accordance with a signal CN3 from ECU 30.

  When charging main power storage device BA and sub power storage devices BB1 and BB2, ECU 30 sends signal UA1 or SD1 to converter 10 and also sends signal UA2 or SD2 to converter 12. Converter 10 turns on the upper arm (switching element Q1) and turns off the lower arm (switching element Q2) in response to signal UA1. Converter 10 turns off the upper arm and the lower arm in response to signal SD1. Converter 12 turns on the upper arm (switching element Q3) and turns off the lower arm (switching element Q4) in response to signal UA2. Converter 12 turns off the upper arm and the lower arm in response to signal SD2.

  Further, the ECU 30 sends a signal CHG to the charger 240. The charging of each power storage device will be described in detail later.

  FIG. 3 is a diagram showing in detail the configuration of charger 240 and the configuration for electrical connection between the hybrid vehicle and the external power source.

  Referring to FIG. 3, charger 240 includes an AC / DC conversion circuit 242, a DC / AC conversion circuit 244, an insulating transformer 246, and a rectifier circuit 248.

  The AC / DC conversion circuit 242 is a single-phase bridge circuit. AC / DC conversion circuit 242 converts AC power into DC power based on signal CHG from ECU 30. The AC / DC conversion circuit 242 also functions as a boost chopper circuit that boosts the voltage by using a coil as a reactor.

  The DC / AC conversion circuit 244 is composed of a single-phase bridge circuit. The DC / AC conversion circuit 244 converts DC power into high-frequency AC power based on CHG from the ECU 30 and outputs it to the isolation transformer 246.

  Insulation transformer 246 includes a core made of a magnetic material, and a primary coil and a secondary coil wound around the core. The primary coil and the secondary coil are electrically insulated and connected to the DC / AC conversion circuit 244 and the rectification circuit 248, respectively. Insulation transformer 246 converts high-frequency AC power received from DC / AC conversion circuit 244 into a voltage level corresponding to the turn ratio of the primary coil and the secondary coil, and outputs the voltage level to rectifier circuit 248. The rectifier circuit 248 rectifies AC power output from the insulating transformer 246 into DC power.

  A voltage between the AC / DC conversion circuit 242 and the DC / AC conversion circuit 244 (voltage between terminals of the smoothing capacitor) is detected by the voltage sensor 182, and a signal representing the detection result is input to the ECU 30. The output current of charger 240 is detected by current sensor 184, and a signal representing the detection result is input to ECU 30.

  ECU 30 generates signal CHG for driving charger 240 and outputs it to charger 240 when main power storage device BA and sub power storage devices BB1, BB2 are charged by power supply 402 outside the vehicle.

  The ECU 30 has a failure detection function of the charger 240 in addition to a control function of the charger 240. If the voltage detected by voltage sensor 182, the current detected by current sensor 184, etc. are equal to or greater than a threshold value, a failure of charger 240 is detected.

  Inlet 250 is provided, for example, on the side of the hybrid vehicle. A connector 310 of a charging cable 300 that connects the hybrid vehicle and the external power source 402 is connected to the inlet 250.

  Charging cable 300 that connects the hybrid vehicle and external power supply 402 includes a connector 310, a plug 320, and a CCID (Charging Circuit Interrupt Device) 330.

  Connector 310 of charging cable 300 is connected to inlet 250 provided in the hybrid vehicle. The connector 310 is provided with a switch 312. When the switch 312 is closed while the connector 310 of the charging cable 300 is connected to the inlet 250 provided in the hybrid vehicle, the connector 310 of the charging cable 300 is connected to the inlet 250 provided in the hybrid vehicle. A cable connection signal PISW indicating that it is present is input to ECU 30. For example, the switch 312 opens and closes in conjunction with a locking fitting (not shown) that locks the connector 310 of the charging cable 300 to the inlet 250 of the hybrid vehicle.

  Plug 320 of charging cable 300 is connected to outlet 400. The outlet 400 is an outlet provided in a house, for example. AC power is supplied from the power source 402 to the outlet 400.

  The CCID 330 has a relay 332 and a control pilot circuit 334. When relay 332 is open, the path for supplying power from power supply 402 to the hybrid vehicle is blocked. When the relay 332 is closed, power can be supplied from the power source 402 to the hybrid vehicle. The state of relay 332 is controlled by ECU 30 in a state where connector 310 of charging cable 300 is connected to inlet 250 of the hybrid vehicle.

  The control pilot circuit 334 has a pilot signal (square wave signal) CPLT on the control pilot line in a state where the plug 320 of the charging cable 300 is connected to the outlet 400, that is, the external power supply 402, and the connector 310 is connected to the inlet 250. Send. Pilot signal CPLT changes periodically by an oscillator provided in control pilot circuit 334.

  When the plug 320 of the charging cable 300 is connected to the outlet 400, the control pilot circuit 334 can output a predetermined pilot signal CPLT even if the connector 310 is disconnected from the inlet 250. However, ECU 30 cannot detect pilot signal CPLT output in a state where connector 310 is removed from inlet 250.

  When plug 320 of charging cable 300 is connected to outlet 400 and connector 310 of charging cable 300 is connected to inlet 250, control pilot circuit 334 generates pilot signal CPLT having a predetermined pulse width (duty cycle). Generate.

  The hybrid vehicle is notified of the current capacity that can be supplied by the pulse width of pilot signal CPLT. For example, the current capacity of charging cable 300 is notified to the hybrid vehicle. The pulse width of pilot signal CPLT is constant without depending on the voltage and current of power supply 402.

  On the other hand, if the type of charging cable used is different, the pulse width of pilot signal CPLT may be different. That is, the pulse width of pilot signal CPLT can be determined for each type of charging cable.

  In the present embodiment, main power storage device BA and sub power storage devices BB1 and BB2 are charged in a state where hybrid vehicle and power source 402 are connected by charging cable 300. AC voltage VAC of power supply 402 is detected by voltage sensor 188 provided inside the hybrid vehicle. The detected voltage VAC is transmitted to the ECU 30.

  FIG. 4 is a functional block diagram showing the configuration of the ECU 30. As shown in FIG. The configuration shown in FIG. 4 can be realized by either hardware or software.

  Referring to FIG. 4, ECU 30 includes a charge control unit 31, a relay control unit 32, a converter control unit 33, an inverter control unit 34, and a leakage determination unit 35.

  Charging control unit 31 receives remaining capacity (also referred to as SOC (State of Charge)) SOC1 of main power storage device BA and remaining capacities SOC2 and SOC3 of sub power storage devices BB1 and BB2. For example, this remaining capacity is defined as 100% when the power storage device is fully charged, and is defined as 0% when the power storage device is completely discharged. Note that the remaining capacity can be calculated by various known methods using the voltage of the power storage device, the charge / discharge current, the temperature of the power storage device, and the like, and thus detailed description thereof will not be repeated here. Charging control unit 31 operates and stops charger 240 by outputting signal CHG based on remaining capacities SOC1, SOC2, and SOC3. Charging control unit 31 causes display device 90 to display information indicating the charging results of main power storage device BA and sub power storage devices BB1 and BB2 in response to command IGON.

  Relay control unit 32 outputs signals CN <b> 1 to CN <b> 3 for controlling connection units 72, 74, and 76 based on the control process of charge control unit 31 and the determination result of leakage determination unit 35.

  Based on voltage VA detected by voltage sensor 42, voltage VH detected by voltage sensor 48, and current IA detected by current sensor 52, converter control unit 33 applies PWM ( A signal PWC1 for controlling (Pulse Width Modulation) is generated. Converter control unit 33 further generates shutdown signal SD1 for stopping converter 10 and upper arm on signal UA1 for fixing the upper arm of converter 10 to the on state.

  Similarly, converter control unit 33 generates signal PWC2 for controlling the switching elements included in converter 12 based on voltage VB1 (or voltage VB2), voltage VH, and current IB1 (or current IB2). Furthermore, converter control unit 33 generates a shutdown signal SD2 for stopping converter 12 and an upper arm on signal UA2 for fixing the upper arm of converter 12 to the on state.

  Converter control unit 33 further generates PWM signal PWC3 for switching control of converter 14.

  Inverter control unit 34 generates a PWM signal for turning on / off a switching element included in inverter 20 based on torque command value TR1 of motor generator MG1, motor current MCRT1 and rotor rotation angle θ1, and voltage VH. The generated PWM signal is output to the inverter 20 as a signal PWI1.

  Inverter control unit 34 generates a PWM signal for turning on / off the switching element included in inverter 22 based on torque command value TR2 of motor generator MG2, motor current MCRT2 and rotor rotation angle θ2, and voltage VH. The generated PWM signal is output to the inverter 22 as the signal PWI2.

  Torque command values TR1 and TR2 are calculated by a vehicle ECU (not shown) based on, for example, the accelerator opening, the brake depression amount, the vehicle speed, and the like. Motor currents MCRT1 and MCRT2 and rotor rotation angles θ1 and θ2 are detected by sensors (not shown).

  When leakage determination unit 35 determines that leakage has occurred in the vehicle system shown in FIG. 1 based on the detection result of leakage detector 80, leakage determination unit 35 outputs the determination result to relay control unit 32 and converter control unit 33. The relay control unit 32 generates and outputs signals CN1 to CN3 for turning off the connection units 72, 74, and 76 according to the determination result of the leakage determination unit 35. Converter control unit 33 generates and outputs signals SD1 and SD2 for stopping converters 10 and 12, respectively.

  Furthermore, leakage determination unit 35 sends information indicating that charging of the power storage device has been forcibly terminated to display device 90. Display device 90 receives information from leakage determination unit 35 and displays that charging of the power storage device has been forcibly terminated.

  At the time of charging each power storage device, the charging control unit 31, the relay control unit 32, the converter control unit 33, and the leakage determination unit 35 exchange information such as processing results with each other.

  Next, control of the system main relay according to the present embodiment will be described in detail. FIG. 5 is a waveform diagram schematically showing changes in the state of the system main relay and the voltage VH.

  Referring to FIG. 5, system main relay SRB generally represents system main relays SRB1, SRB2, and SRB3 shown in FIG. Similarly, the system main relay SRG generically shows the system main relays SRG1 to SRG3, and the system main relay SRP generically shows the system main relays SRP1 to SRP3.

  First, the operation of the connecting portion (connection processing of the connecting portion by the ECU 30) when connecting the power storage device (BA, BB1, BB2) to the corresponding converter (10, 12) will be described. At time t1, system main relay SRB changes from the off state to the on state. Next, at time t2, system main relay SRP is turned on.

  Prior to time t2, voltage VH is zero. For this reason, when the power storage device is connected to the corresponding power line (positive line and negative line), a large current may flow through the power line because the difference between the voltage (VA, VB1, VB2) of the power storage device and the voltage VH is large. There is. As a result, the system main relay may be welded. For this reason, it is necessary to limit the current flowing in the power line.

  Therefore, system main relay SRP is turned on prior to system main relay SRG on the negative electrode side of the power storage device. While the system main relay SRP is on, the output current from the power storage device is limited by the limiting resistor. For this reason, the voltage VH gradually increases. When voltage VH increases and becomes substantially equal to the voltage of the power storage device, system main relay SRG is turned on, and thereafter system main relay SRP is turned off (time t3). Since the period from time t2 to time t3 is a time for accumulating charges in the capacitor C, this period is also referred to as a precharge period. When the system main relay SRP is turned off, the connection process is completed (time t4).

  Next, the operation of the connecting portion (the connection portion blocking process by the ECU 30) when the connection between the power storage device (BA, BB1, BB2) and the corresponding converter (10, 12) is cut will be described. It is assumed that the blocking process starts from time t5.

  At time t5, system main relays SRB and SRG are in the on state. At time t6, system main relay SRG is turned off. Thereafter, a process for discharging the capacitor C is performed.

  The electric charge accumulated in capacitor C is released by motor generators MG1 and / or MG2. At this time, motor generators MG1 and / or MG2 are controlled so as not to generate torque. An example of the discharge control executed at this time will be described. Based on the rotor rotation angles (θ1, θ2) of motor generators MG1, MG2, inverter control unit 34 determines the vector direction of the discharge current. That is, inverter control unit 34 controls inverters 20 and 22 such that the discharge current vector is oriented in a direction parallel to the d-axis (the direction of the magnetic field formed by the rotor of the motor generator). By controlling the discharge in this way, the inverters 20 and 22 are controlled so that no torque is generated on the q-axis (the direction of the vector generating the torque). Note that this discharge control is an example, and other discharge control can be adopted as long as it is a control for discharging the charge accumulated in the capacitor C.

  When voltage VH becomes 0 at time t7, system main relay SRB is turned off. As a result, the blocking process ends.

  Although not shown in FIG. 5, the welding determination of the system main relay may be performed in addition to the connection and disconnection of the system main relay. FIG. 5 shows the change in the voltage VH when each system main relay is normal. However, when any of the system main relays is welded, the change in the voltage VH is the behavior of the VH shown in FIG. Different. As a result, the welding of each system main relay can be determined.

  For example, before time t1, welding determination of system main relays SRP, SRG (or system main relays SRB, SRP) is performed. In addition, welding determination of system main relay SRP is performed during a period from time t1 to t4. Further, welding determination of system main relay SRG is performed during a period from time t5 to time t7.

  Next, charging control for the power storage device according to the present embodiment will be described. FIG. 6 is a flowchart illustrating a charging process for the power storage device according to the present embodiment. The process shown in this flowchart is executed by ECU 30 when a predetermined condition is satisfied (for example, when power supply 402 and hybrid vehicle are connected by charging cable 300).

  Referring to FIG. 6, first, a process for charging main power storage device BA is performed (step S1). Next, a process for charging sub power storage device BB1 is performed (step S2). Subsequently, a process for charging sub power storage device BB2 is performed (step S3). The order of charging sub power storage devices BB1 and BB2 is not limited as shown in FIG. Then, when charging of sub power storage devices BB1 and BB2 is completed, main power storage device BA is charged again (step S4). When the process of step S4 ends, the entire process ends.

  In step S1, main power storage device BA is preliminarily charged. The processing in step S1 is for accumulating a certain amount of power in main power storage device BA prior to charging of sub power storage devices BB1 and BB2. While the sub power storage devices BB1 and BB2 are charged, the electric power stored in the main power storage device BA is consumed by an auxiliary machine or the like. Therefore, in step S4, main power storage device BA is charged again.

  FIG. 7 is a timing chart corresponding to the processing shown in the flowchart of FIG. Referring to FIG. 7, at time t11, system main relay (SMR) corresponding to main power storage device BA changes from the off state to the on state. In FIG. 7, the connection process shown in FIG. 5 is represented as a transition from OFF to ON of the waveform of the system main relay (SMR), and the cutoff process shown in FIG. 5 is changed from ON to OFF in the waveform of the system main relay. It is expressed by the transition of.

  When the system main relay on the main power storage device BA side is turned on at time t11, the main power storage device BA is connected to the positive electrode line PL1 and the negative electrode line NL. On the other hand, the system main relays of sub power storage devices BB1 and BB2 are both off. Thereby, only main power storage device BA is charged. As a result, the remaining capacity of main power storage device BA increases from initial value A to predetermined value B. When the value of SOC reaches predetermined value B, ECU 30 determines that charging of main power storage device BA has ended.

  At time t12, the system main relay on the sub power storage device BB1 side is turned on. Thereby, charging of sub power storage device BB1 is started. As will be described later, after completion of charging of main power storage device BA, converters 10 and 12 are controlled so that power from charger 240 is not supplied to main power storage device BA. If the main power storage device BA and the sub power storage device BB1 are turned on when the sub power storage device BB1 is charged, a short-circuit current may flow between them. By stopping the converters 10 and 12, such a problem can be prevented. Further, if the sub power storage devices BB1 and BB2 are turned on when the sub power storage device BB1 is charged, a short circuit current may flow between them. When the system main relay on the sub power storage device BB1 side is turned on, the system main relay on the sub power storage device BB2 side is turned off. Therefore, it is possible to avoid a short circuit current from flowing between sub power storage devices BB1 and BB2.

  At time t13, charging of sub power storage device BB1 is completed. As a result, the system main relay on the sub power storage device BB1 side is turned off. Subsequently, at time t14, the system main relay on the side of sub power storage device BB2 is turned on, and charging of sub power storage device BB2 is started. Also at this time, it is possible to avoid a short-circuit current from flowing between the sub power storage devices BB1 and BB2. When charging of sub power storage device BB2 is completed at time t15, the system main relay on the side of sub power storage device BB2 is turned off.

  Here, the operation of auxiliary machine 16 may be continued in the period for charging sub power storage devices BB1, BB2, that is, the period from time t12 to t15. For example, when the auxiliary machine 16 is a watch, it is necessary to supply electric power to the auxiliary machine 16 in order to always operate. Further, as shown in FIG. 1, the electric power (voltage VD) stored in auxiliary battery SB is supplied to ECU 30. The ECU 30 must control the charger 240 while charging the sub power storage devices BB1 and BB2. Therefore, electric power is supplied from the auxiliary battery SB to the ECU 30 during this period. If the system main relay on the main power storage device BA side is turned off while charging the sub power storage devices BB1 and BB2, the auxiliary battery SB may increase due to the power consumption of the auxiliary device 16 and the ECU 30 (so-called battery increase occurs). is there.

  In order to prevent this problem, in the present embodiment, while sub power storage devices BB1 and BB2 are charged, ECU 30 keeps the system main relay (connection portion 72) on the main power storage device BA side in the on state, and converter 14 Continue the voltage conversion operation. Thereby, since the electric power stored in main power storage device BA is consumed by auxiliary device 16 and ECU 30, the remaining capacity of main power storage device BA decreases from predetermined value B. Therefore, at time t15, recharging of main power storage device BA is started. The remaining capacity of main power storage device BA recovers to a predetermined value B by recharging. When the remaining capacity of main power storage device BA reaches predetermined value B, the system main relay on main power storage device BA is turned off (time t16).

  That is, charging of main power storage device BA at times t11 to t12 is charging for securing driving power of auxiliary machine 16 and ECU 30 while charging sub power storage devices BB1 and BB2. Charging of main power storage device BA at times t11 to t12 corresponds to the process of step S1 in FIG.

  The charging of the sub power storage device BB1 at times t12 to t13 corresponds to the process of step S2 in FIG. Charging of the sub power storage device BB2 at times t14 to t15 corresponds to the process of step S3 in FIG.

  Charging of main power storage device BA at times t15 to t16 is charging for compensating for power consumed during charging of sub power storage devices BB1 and BB2. Charging of main power storage device BA at times t15 to t16 corresponds to the process of step S4 in FIG.

  As described above, in the present embodiment, the system main relay (connection portion 72) of the main power storage device (main power storage device BA) is kept on even while the sub power storage devices (sub power storage devices BB1, BB2) are being charged. The voltage conversion operation by the converter 14 is continued. Thus, the operation of the auxiliary machine (including the ECU) can be continued during the charging period of the sub power storage device, and the auxiliary battery SB can be prevented from rising. If the auxiliary battery is raised and the ECU 30 stops, it is expected that not only charging of the sub power storage devices BB1 and BB2 will be impossible, but also the control of the vehicle system will be affected. According to the present embodiment, such a problem can be avoided.

  FIG. 8 is a timing chart illustrating the charging process of the power storage device shown in FIGS. 6 and 7 in more detail.

  Referring to FIG. 8, the period from time t11 to t16 corresponds to the period from time t11 to t16 shown in FIG. 8, the connection process shown in FIG. 5 is represented as a transition from OFF to ON of the waveform of the system main relay (SMR), and the disconnection process shown in FIG. It is represented by a transition from on to off in the waveform of.

  At time t11, ECU 30 transmits signal CN1 to connection portion 72, and switches system main relay (SMR) on the main power storage device BA side from the off state to the on state. At time t21, the ECU 30 changes the potential of the pilot signal CPLT. As a result, the control pilot circuit 334 turns on the relay 332 provided in the CCID 330. At time t22, ECU 30 transmits signal UA1 to converter (CNV) 10 to fix the upper arm of converter 10 in the on state. Further, at time t23, the ECU 30 transmits a signal CHG to the charger 240 to start the operation of the charger 240 (turns on the charger 240). Thereby, charging of main power storage device BA is started.

  Here, referring to FIG. 2, when main power storage device BA is charged, power is supplied to positive line PL <b> 2 via power supply 402, charging cable 300, and charger 240. The electric power supplied to positive electrode line PL2 is supplied to main power storage device BA via reactor L2, diode D3, switching element Q1 (upper arm), reactor L1, positive electrode line PL1, and connecting portion 72.

  ECU 30 (charge control unit 31) detects the remaining capacity (SOC1) of main power storage device BA. When the remaining capacity of main power storage device BA reaches predetermined value B at time t24, ECU 30 stops charger 240 (turns off). Then, ECU 30 sends signal SD1 to converter 10 and stops converter 10. Therefore, at time t25, the upper arm of converter 10 changes from the on state to the off state.

  Converters 10 and 12 are stopped at time t25. Thereafter, in order to discharge capacitor C (shown as DC in the figure), ECU 30 operates the lower arm of converter 12 for a predetermined period. Thereafter, ECU 30 transmits signal SD2 to converter 12 to stop converter 12.

  Next, at time t12, ECU 30 transmits signal CN2 to connection unit 74, and turns on the system main relay on the side of sub power storage device BB1. Even at time t12, the system main relay on the main power storage device BA side remains on. Therefore, the electric power necessary for driving auxiliary machine 16 and ECU 30 can be supplied by main power storage device BA (and converter 14). After the system main relay on the sub power storage device BB1 side is turned on, the ECU 30 operates the charger 240 (turns the charger 240 on). Thereby, sub power storage device BB1 is charged.

  Since the converter 10 is stopped when the sub power storage device BB1 is charged, power from the power source 402 is not supplied to the main power storage device BA. When the remaining capacity (SOC2) of sub power storage device BB1 reaches a predetermined value, ECU 30 stops charger 240 (turns off). Thereafter, the capacitor C is discharged by the converter 12. After completion of discharging of the capacitor C, the ECU 30 turns off the system main relay on the sub power storage device BB1 side (time t13).

  Subsequently, at time t <b> 14, ECU 30 transmits signal CN <b> 3 to connection unit 76 to turn on the system main relay on the sub power storage device BB <b> 2 side. At time t14, the system main relay on the main power storage device BA side remains on. Therefore, the electric power necessary for driving auxiliary machine 16 and ECU 30 can be supplied by main power storage device BA (and converter 14).

  After the system main relay on the sub power storage device BB2 side is turned on, the ECU 30 operates the charger 240 (turns on the charger 240). Thereby, sub power storage device BB2 is charged. When the remaining capacity (SOC3) of sub power storage device BB2 reaches a predetermined value, ECU 30 stops charger 240 (turns off). Thereafter, the capacitor C is discharged by the converter 12. After completion of discharging of the capacitor C, the ECU 30 turns off the system main relay on the sub power storage device BB2 side (time t15).

  Thereafter, ECU 30 transmits signal UA1 to converter 10 to turn on the upper arm of converter 10. Furthermore, the ECU 30 sends a signal CHG to the charger 240 to operate (turn on) the charger 240. Thereby, main power storage device BA is charged in the same manner as in the period from time t22 to time t25. When the remaining capacity (SOC1) of main power storage device BA reaches predetermined value B, ECU 30 stops charger 240 (turns off). Next, ECU 30 transmits signal SD1 to converter 10 to turn off the upper arm of converter 10. Thereafter, ECU 30 changes the potential of pilot signal CPLT. As a result, the control pilot circuit 334 turns off the relay 332 provided in the CCID 330. At time t16, ECU 30 turns off the system main relay on the main power storage device BA side.

  Furthermore, according to the present embodiment, leakage detector 80 is provided on the main power storage device BA side. By providing the leakage detector 80 near the power source (power storage device), the accuracy of detecting the leakage can be improved. Therefore, it is preferable to provide a leakage detector for each power storage device in terms of leakage detection, but this increases the cost. Therefore, in the present embodiment, only leakage detector 80 that is directly connected to main power storage device BA is provided.

  Main power storage device BA is connected to positive electrode line PL1 and negative electrode line NL by connection portion 72. As a result, leakage detector 80 is electrically connected to the vehicle system shown in FIG. Therefore, electric leakage can be detected by electric leakage detector 80 when charging main power storage device BA and sub power storage devices BB1 and BB2.

FIG. 9 is a block diagram illustrating a configuration example of the leakage detector 80 shown in FIG.
Referring to FIG. 9, a circuit system 200 is a functional block diagram of the vehicle system shown in FIG. Further, the ground 1 shown in FIG. 9 corresponds to the vehicle body in the vehicle.

  The leakage detector 80 includes an oscillation circuit 81 as a signal generation unit, a detection resistor 82, a coupling capacitor 83, a band pass filter (BPF) 84, a circuit block 85 including an offset circuit and an amplifier circuit, and overvoltage protection. Diode 87, resistor 86, capacitor 88, and control circuit 110.

  The oscillation circuit 81 applies a pulse signal SIG that changes at a predetermined frequency (predetermined period Tp) to the node NA. The detection resistor 82 is connected between the node NA and the node N1. Coupling capacitor 83 is connected between main power storage device BA (or sub power storage devices BB1 and BB2) to be detected for leakage and node N1. The bandpass filter 84 has an input terminal connected to the node N1 and an output terminal connected to the node N2. The passband frequency of the bandpass filter 84 is designed according to the frequency of the pulse signal SIG.

  The circuit block 85 is connected between the node N2 and the node N3. The circuit block 85 amplifies a voltage change in the vicinity of the threshold voltage that is set when the insulation resistance is detected in the pulse signal that has passed through the band-pass filter 84. The overvoltage protection diode 87 has a cathode connected to the constant voltage node and an anode connected to the node NB to remove the surge voltage (high voltage, negative voltage). Resistor 86 is connected between nodes N3 and NB. Capacitor 88 is connected between node NB and ground 1. The resistor 86 and the capacitor 88 function as a filter that removes noise from the signal output from the circuit block 85.

  The control circuit 110 controls the oscillation circuit 81. In addition, the control circuit 110 detects the voltage of the node NB and detects a decrease in the insulation resistance Ri based on the detected voltage. Control circuit 110 includes an oscillation command unit 111, an A / D conversion unit 112, and a determination unit 113.

  The oscillation command unit 111 instructs the oscillation circuit 81 to generate the pulse signal SIG and instructs the duty ratio of the pulse signal SIG to be changed. The A / D converter 112 A / D converts the voltage (detected voltage) of the node NB detected at a predetermined sampling period Ts. Since the sampling period Ts is sufficiently shorter than the period Tp of the pulse signal SIG, the maximum voltage (peak voltage Vp) and the minimum voltage of the node NB can be detected. The determination unit 113 compares the value of the peak voltage Vp acquired from the A / D conversion unit 112 with a threshold value. As a result, the control circuit 110 detects whether the insulation resistance Ri has decreased.

Next, an operation for detecting a decrease in the insulation resistance Ri will be described.
The pulse signal SIG generated by the oscillation circuit 81 is applied to a series circuit including a detection resistor 82, a coupling capacitor 83, an insulation resistor Ri, and a bandpass filter 84. As a result, the node N1 corresponding to the connection point of the detection resistor 82 and the coupling capacitor 83 has a voltage dividing ratio of the insulation resistance Ri and the detection resistor 82 (resistance value Rd): Ri / (Rd + Ri) and the amplitude of the pulse signal SIG ( A pulse voltage having a peak value as a product of the voltage + B) which is a power supply voltage is generated. The voltage + B may be, for example, the voltage VD (see FIG. 1) of the auxiliary battery SB, but is not limited to the voltage VD.

  In the pulse voltage generated at the node N1, components other than the frequency of the pulse signal SIG are attenuated by the band-pass filter 84. Of the pulse signal SIG that has passed through the band pass filter 84, only the voltage change near the threshold voltage is amplified by the circuit block 85. A signal output from circuit block 85 is transmitted to node NB. When a signal is transmitted from the node N3 to the node NB, the surge voltage is removed by the overvoltage protection diode 87, and noise is removed by the resistor 86 and the capacitor 88.

  When the insulation resistance Ri is normal, Ri >> Rd. As Ri increases, the peak voltage Vp becomes substantially equal to the voltage + B. On the other hand, when the insulation resistance Ri is lowered, the voltage division ratio: Ri / (Rd + Ri) is lowered, so that the peak voltage Vp is lowered.

  FIG. 10 is a diagram illustrating the relationship between the insulation resistance Ri and the maximum voltage (peak voltage Vp) at the node NB.

  Referring to FIG. 10, as Ri increases, peak voltage Vp increases, and is approximately equal to voltage + B. Therefore, if threshold voltage Vt is determined according to the voltage division ratio between the allowable lower limit value of insulation resistance Ri and resistance value Rd of detection resistor 82, control circuit 110 causes maximum value (peak voltage Vp) to change at node NB. ) And the value of the threshold voltage Vt, a decrease in the insulation resistance Ri can be detected.

  FIG. 11 is a diagram for explaining voltage waveforms detected by the control circuit 110 of FIG. 9 when a decrease in the insulation resistance Ri is detected.

  Referring to FIG. 11, when insulation is normal, peak voltage Vp exceeds threshold voltage Vt and reaches maximum voltage Vmax (this voltage is approximately equal to voltage + B). On the other hand, when insulation is abnormal, the peak voltage Vp is smaller than the threshold voltage Vt.

  FIG. 12 is a flowchart for explaining the processing of the ECU 30 when leakage is detected. The processing shown in this flowchart is called and executed from the main routine at predetermined intervals, for example.

  Referring to FIG. 12, ECU 30 determines whether or not a leakage has occurred (step S11). More specifically, the leakage determination unit 35 determines that leakage has occurred when the leakage detector 80 outputs a signal indicating a decrease in insulation resistance. When the leakage determination unit 35 determines that leakage has not occurred (NO in step S11), the entire process is returned to the main routine. On the other hand, when it is determined that leakage has occurred by leakage determination unit 35 (YES in step S11), relay control unit 32 includes all of connections included in connection units 72, 74, and 76 based on the determination result of leakage determination unit 35. Signals CN1 to CN3 for turning off the system main relay are generated and output. This turns off all system main relays. Further, ECU 30 turns off relay 332 included in CCID 330. Specifically, the ECU 30 causes the control pilot circuit 334 to cut off the relay 332 by changing the potential of the pilot signal CPLT. (Step S12).

  Subsequently, converter control unit 33 generates and outputs signals SD1 and SD2 for stopping converters 10 and 12 based on the determination result of leakage determination unit 35 (step S13). Further, the charging control unit 31 generates a signal CHG for stopping the operation of the charger 240 and outputs the signal CHG to the charger 240. Thereby, the charger 240 is stopped (turned off) (step S14). When the process of step S14 ends, the entire process is returned to the main routine.

  In step S12, a process for turning off all the system main relays included in connection units 72, 74, and 76 is executed, and a process for turning off relay 332 included in CCID 330 is executed after the process of step S14. May be. In this case, when the process for turning off the relay 332 is completed, the entire process is returned to the main routine.

  As described above, according to the present embodiment, connection unit 72 provided corresponding to main power storage device BA is set in a conductive state and voltage conversion operation by converter 14 is continued during charging of the sub power storage device. Let Thereby, it is possible to prevent the auxiliary battery from running out of battery during charging of the sub power storage device.

  Further, according to the present embodiment, it is possible to detect a leakage during charging of each of the plurality of power storage devices without increasing the number of leakage detectors.

  In the above description, the series / parallel type hybrid vehicle in which the power of the engine 2 is divided by the power split mechanism 4 and transmitted to the wheels 6 and the motor generator MG1 has been described. It can also be applied to hybrid vehicles. For example, a so-called series-type hybrid vehicle that uses the engine 2 only to drive the motor generator MG1 and generates the driving force of the vehicle only by the motor generator MG2, or only regenerative energy among the kinetic energy generated by the engine 2 is used. The present invention can also be applied to a hybrid vehicle that is recovered as electric energy, a motor-assist type hybrid vehicle in which a motor assists the engine as the main power if necessary.

  The present invention can also be applied to an electric vehicle that does not include the engine 2 and runs only with electric power, and a fuel cell vehicle that further includes a fuel cell as a power source in addition to a power storage device.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

1 is an overall block diagram of a hybrid vehicle shown as an example of a vehicle equipped with a power supply system according to an embodiment of the present invention. FIG. 7 is a circuit diagram showing a configuration of converters 10 and 12 and connecting portions 72 to 76 shown in FIG. 1. It is a figure which shows in detail the structure for the charger 240, and the structure for electrical connection of a hybrid vehicle and an external power supply. 2 is a functional block diagram showing a configuration of an ECU 30. FIG. It is a wave form diagram which shows typically the change of the state of system main relay, and voltage VH. It is a flowchart explaining the charge process of the electrical storage apparatus by this Embodiment. 7 is a timing chart corresponding to the process shown in the flowchart of FIG. 6. 8 is a timing chart for explaining in more detail the charging process of the power storage device shown in FIGS. 6 and 7. It is a block diagram explaining the structural example of the leak detector 80 shown in FIG. It is a figure explaining the relationship between the insulation resistance Ri and the maximum voltage (peak voltage Vp) in the node NB. It is a figure explaining the voltage waveform detected by the control circuit 110 of FIG. 9 when the fall of the insulation resistance Ri is detected. It is a flowchart explaining the process of ECU30 at the time of a leak detection.

Explanation of symbols

  1 ground, 2 engine, 4 power split mechanism, 6 wheels, 10, 12, 14 converter, 16 auxiliary machine, 20, 22 inverter, 31 charge control unit, 32 relay control unit, 33 converter control unit, 34 inverter control unit, 35 Leakage determination unit, 42, 44, 46, 48 Voltage sensor, 52, 54, 56 Current sensor, 62, 64, 66 Temperature sensor, 72, 74, 76 Connection unit, 80 Leakage detector, 81 Oscillation circuit, 82 detection Resistance, 83 Coupling capacitor, 84 Bandpass filter, 85 Circuit block, 86 Resistance, 87 Overvoltage protection diode, 88 Capacitor, 90 Display device, 110 Control circuit, 111 Oscillation command section, 112 A / D conversion section, 113 judgment Part, 182, 188 voltage sensor, 184 current sensor, 200 circuit system, 40 charger, 242 AC / DC conversion circuit, 244 DC / AC conversion circuit, 246 isolation transformer, 248 rectifier circuit, 250 inlet, 300 charging cable, 310 connector, 312 switch, 320 plug, 330 CCID, 332 relay, 334 control Pilot circuit, 400 outlets, 402 power supply, 1000 hybrid vehicle, BA main power storage device, BB1, BB2 sub power storage device, C, C1, C2 capacitor, D1-D4 diode, L1, L2 reactor, MG1, MG2 motor generator, N1- N3, NA, NB node, NL negative line, PL1-PL4 positive line, Q1-Q4 switching element, RA, RB1, RB2 limiting resistance, Ri insulation resistance, SB auxiliary battery, SRB1, SR 1, SRG1, SRB2, SRP2, SRG2, SRB3, SRP3, SRG3 system main relay.

Claims (8)

First and second power storage devices;
A first power line provided corresponding to the first power storage device;
A second power line provided corresponding to the second power storage device;
A first connecting portion configured to be capable of electrical connection and disconnection between the first power storage device and the first power line;
A second connection portion configured to be capable of electrical connection and disconnection between the second power storage device and the second power line;
Connected between the first power line and the auxiliary machine, the voltage of the electric power supplied from the first power storage device via the first connection part and the first power line is changed to the auxiliary machine. A voltage conversion device that converts the voltage into a predetermined voltage for operation;
A third power storage device that is connected in parallel to the auxiliary device with respect to the voltage conversion device and stores electric power supplied from the voltage conversion device;
A charging device connected to the first and second power lines for charging the first and second power storage devices with an external power source outside the vehicle;
A control device for controlling the first and second connecting portions and the charging device;
The control device sets the second connection portion to a conductive state when charging the second power storage device, and controls the charging device so that power from the external power supply is supplied to the second power line. While controlling, the power supply system of a vehicle which sets the said 1st connection part to a conduction | electrical_connection state and continues operation | movement of the said voltage converter.   In the control device, the first power storage device is charged prior to charging the second power storage device, and the remaining capacity of the first power storage device is a predetermined value after charging of the second power storage device is completed. 2. The vehicle power supply system according to claim 1, wherein the first and second connection units and the charging device are controlled so that the first power storage device is charged until the first power storage device is reached.   The control device sets the first and second connection portions to a conductive state and a non-conductive state, respectively, and charges power from the external power source to the first power line when charging the first power storage device. The vehicle power supply system according to claim 2, wherein the charging device is controlled to be supplied. The power supply system includes:
A leakage detector directly connected to the first power storage device;
The said control apparatus determines the presence or absence of the electric leakage in the said power supply system based on the detection result of the said electric leakage detector at the time of charge of the said 1st electrical storage apparatus and the said 2nd electrical storage apparatus. 4. The vehicle power supply system according to 2 or 3.   5. The vehicle power supply system according to claim 1, wherein the predetermined voltage is supplied to the control device as an operating voltage of the control device. 6. The power supply system includes:
Further comprising a third power line;
The charging device is:
A first power converter connected to the first and third power lines and configured to enable bidirectional power conversion;
A second power converter connected to the second and third power lines and configured to be capable of bidirectional power conversion;
6. The vehicle power supply system according to claim 1, further comprising: a charger configured to be able to output electric power supplied from the external power supply to the second power line. Each of the first and second power conversion devices includes:
A power semiconductor switching element inserted and connected to a current path between a corresponding power line of the first and second power lines and the third power line;
A diode element connected in parallel with the power semiconductor switching element, with the direction from the corresponding power line toward the third power line as a forward direction,
When the control device outputs power supplied from the external power source to the first power line via the charger, the power semiconductor switching of each of the first and second power conversion devices In the case where power is supplied from the external power supply via the charger to the second power line while the element is set in a conductive state, each of the first and second power converters The vehicle power supply system according to claim 6, wherein the power semiconductor switching element is set in a non-conduction state. A vehicle power supply system according to any one of claims 1 to 7,
A vehicle comprising the auxiliary machine.

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