JP2010115050A - Power supply system for vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply system for a vehicle, charging a battery without deteriorating the performance of the vehicle as much as possible, even when the charging time is not sufficient. <P>SOLUTION: When the charging time for charging the battery from outside the vehicle is within a predetermined time, a control unit 30 controls a charging device 39 to execute uniform charging of a master battery MB and a slave battery SB1 so that both batteries have the equivalent charged state SOC. When the charging time exceeds the predetermined time, the control unit 30 controls the charging device 39 so as to charge the slave battery SB1 and the master battery MB in order. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

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

  In recent years, vehicles such as electric vehicles and hybrid vehicles incorporating an electric drive system using a battery as an energy source have been actively developed.

Japanese Unexamined Patent Publication No. 2003-209969 (Patent Document 1) discloses a method and apparatus for using a high voltage inverter motor set in a low voltage battery module. The power control system for an electric traction motor for a vehicle disclosed in this document includes at least one inverter that provides adjusted electric power to the electric traction motor, each of which includes a battery and a boost / buck DC / DC converter. And a plurality of current stages for providing DC power to at least one inverter. The current stage is controlled to maintain the output voltage to at least one inverter.
JP 2003-209969 A JP 2008-109840 A

  In recent years, even in hybrid vehicles, it has been studied to connect a commercial power supply outside the vehicle to the vehicle so that the on-board battery can be charged. If the vehicle is driven by electric power charged from the outside, the exhaust gas is reduced and the fuel cost can be reduced. In order to enjoy this merit, it is better to carry out EV (Electric Vehicle) running in which the hybrid vehicle runs with only electric power charged from the outside as much as possible and the engine that consumes fuel is not driven.

  In order to increase the power that can be charged when plug-in charging is performed to charge power from the outside of the vehicle, it is also considered to install a plurality of batteries in the vehicle. However, in the case where such a plurality of batteries are mounted, there is room for studying the priority order of charging the plurality of batteries at the time of external charging. If the charging time is sufficiently long, all of the plurality of batteries are sufficiently charged. However, if charging is possible only for a short time, the charging states of the plurality of batteries may be changed to various states. . For example, sufficient charging can be performed for some batteries, and almost no charging can be performed for other batteries, and charging can be performed for a plurality of batteries little by little. The EV running performance of the vehicle may differ depending on the state of charge of the plurality of batteries.

  As described above, when external charging is performed, a charging method specialized for charging in a short time is not disclosed in the above Japanese Patent Application Laid-Open No. 2003-209969.

  An object of the present invention is to provide a vehicle power supply system that can perform charging so that the performance of the vehicle is reduced as much as possible even when the charging time is not sufficient.

  In summary, the present invention provides a power supply system for a vehicle, the first power storage device, the second power storage device, a charging device for charging the first and second power storage devices from the outside of the vehicle, And a control device for controlling the charging device. When the charging time for charging the first and second power storage devices from the outside of the vehicle is within a predetermined time, the control device makes the charge states of the first and second power storage devices equal. The charging device is controlled so as to perform equal charging for charging. When the charging time exceeds a predetermined time, the control device charges the second power storage device without charging the first power storage device until the second power storage device reaches a predetermined charging state. And after the second power storage device reaches a predetermined charging state, the charging device is controlled so that the second power storage device is charged sequentially without charging the first power storage device. .

  Preferably, when the first and second charging devices are charged from the outside of the vehicle using the charging device, the control device causes the charging device to perform equal charging from the start of charging to a predetermined time, and from the start of charging. After charging for a predetermined time, the charging device is caused to execute charging sequentially.

  Preferably, when the charge state of the first and second power storage devices is different at the start of equal charge, the control device sets the charge state of the first and second power storage devices so that the charge states are substantially equal. The charging device is controlled so that only the lower one is charged.

  Preferably, when the charge states of the first and second power storage devices are different at the start of the equal charge, the control device determines whether the first and second power storage devices are in accordance with the charge states of the first and second power storage devices. The distribution of the charging power is determined so that the charging power to the lower charging state of the two power storage devices is larger than the charging power to the higher charging state of the first and second power storage devices.

  Preferably, the charging device is provided between the first power storage device and the electric load and performs voltage conversion, and the charging device is provided between the second power storage device and the electric load and performs voltage conversion. A second voltage converter; and a charger that is connected to a path that electrically connects the second power storage device and the second voltage converter, and that supplies power received from a power source outside the vehicle to the path.

  More preferably, the vehicle power supply system further includes a third power storage device provided in parallel with the second power storage device with respect to the second voltage converter. The charging device further includes a relay that selects one of the second and third power storage devices and connects to the second voltage converter. The charger is connected between the relay on the path and the second voltage converter.

  According to the present invention, even when only a short charging time can be taken, it is possible to reduce the performance during EV traveling as much as possible.

  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 a circuit diagram showing a configuration of a vehicle 1 equipped with a vehicle power supply system.
Referring to FIG. 1, vehicle 1 includes batteries MB, SB1, SB2, which are power storage devices, voltage converters 12A, 12B, smoothing capacitors C1, C2, CH, and voltage sensors 10A, 10B1, 10B2, 13, 21A, 21B, air conditioner 40, DC / DC converter 6, auxiliary machine 7, inverters 14, 22, engine 4, motor generators MG1, MG2, power split mechanism 3, wheel 2, and control device 30.

  The power supply system for the vehicle shown in the present embodiment includes battery MB as a master power storage device, power supply line PL2 that supplies power to inverter 14 that drives motor generator MG2, master power storage device (MB), and power supply line PL2. Voltage converter 12A that is a voltage converter that performs voltage conversion, batteries SB1 and SB2 that are a plurality of slave power storage devices provided in parallel to each other, and a plurality of slave power storage devices (SB1 and SB2) And a voltage converter 12B that is a voltage converter that performs voltage conversion. Air conditioner 40 and DC / DC converter 6 are connected to power supply line PL1A and ground line SL2. For example, a DC voltage of 14 V is supplied as a power supply voltage from the DC / DC converter 6 to the auxiliary machine 7.

  The voltage converter (12B) is selectively connected to any one of the plurality of slave power storage devices (SB1, SB2) to perform voltage conversion.

  The slave power storage device (one of SB1 or SB2) and the master power storage device (MB) can output, for example, the maximum power allowed for the electrical load (22 and MG2) connected to the power supply line by simultaneous use. The dischargeable capacity is set as shown. As a result, traveling at maximum power is possible in EV (Electric Vehicle) traveling without using the engine. If the power storage state of the slave power storage device deteriorates, the slave power storage device may be replaced and run further. When the power of the slave power storage device is consumed, the maximum power can be traveled without using the slave power storage device by using the engine in addition to the master power storage device.

  Further, with such a configuration, the voltage converter 12B is shared by a plurality of slave power storage devices, so that the number of voltage converters need not be increased by the number of power storage devices. In order to further extend the EV travel distance, a battery may be added in parallel to the batteries SB1 and SB2.

  Smoothing capacitor C1 is connected between power supply line PL1A and ground line SL2. The voltage sensor 21 </ b> A detects the voltage VLA across the smoothing capacitor C <b> 1 and outputs it to the control device 30. The voltage converter 12A boosts the voltage across the terminals of the smoothing capacitor C1.

  Smoothing capacitor C2 is connected between power supply line PL1B and ground line SL2. The voltage sensor 21B detects the voltage VLB across the smoothing capacitor C2 and outputs it to the control device 30. The voltage converter 12B boosts the voltage across the terminals of the smoothing capacitor C2.

  Smoothing capacitor CH smoothes the voltage boosted by voltage converters 12A and 12B. The voltage sensor 13 detects the inter-terminal voltage VH of the smoothing capacitor CH and outputs it to the control device 30.

  Inverter 14 converts the DC voltage supplied from voltage converter 12B or 12A into a three-phase AC voltage and outputs the same to motor generator MG1. Inverter 22 converts the DC voltage supplied from voltage converter 12B or 12A into a three-phase AC voltage and outputs the same to motor generator MG2.

  Power split device 3 is a mechanism that is coupled to engine 4 and motor generators MG1 and MG2 and distributes power between them. For example, as the power split mechanism, a planetary gear mechanism having three rotating shafts of a sun gear, a planetary carrier, and a ring gear can be used. In the planetary gear mechanism, if rotation of two of the three rotation shafts is determined, rotation of the other one rotation shaft is forcibly determined. These three rotation shafts are connected to the rotation shafts of engine 4 and motor generators MG1, MG2, respectively. The rotating shaft of motor generator MG2 is coupled to wheel 2 by a reduction gear and a differential gear (not shown). Further, a reduction gear for the rotation shaft of motor generator MG2 may be further incorporated in power split device 3.

  Vehicle 1 further includes system main relay SMRB connected between the positive electrode of battery MB and power supply line PL1A, and system main relay SMRG connected between the negative electrode of battery MB (ground line SL1) and node N2. Including.

  System main relays SMRB and SMRG are controlled to be in a conductive / non-conductive state in accordance with a control signal supplied from control device 30.

  Voltage sensor 10A measures voltage VBA between the terminals of battery MB. Although not shown, in order to monitor the state of charge of the battery MB together with the voltage sensor 10A, a current sensor for detecting the current flowing through the battery MB is provided. As the battery MB, for example, a secondary battery such as a lead storage battery, a nickel metal hydride battery, or a lithium ion battery, or a large capacity capacitor such as an electric double layer capacitor can be used.

  Vehicle 1 further includes a relay SR2B connected between the positive electrode of battery SB1 and power supply line PL1B, a relay SR2G connected between the negative electrode of battery SB1 and ground line SL2, and a positive electrode and power supply of battery SB2. Relay SR3B connected between line PL1B and relay SR3G connected between the negative electrode of battery SB2 and ground line SL2. Relays SR <b> 2 </ b> B, SR <b> 2 </ b> G, SR <b> 3 </ b> B, and SR <b> 3 </ b> G are controlled to be in a conductive / non-conductive state according to a control signal supplied from control device 30. As will be described later, ground line SL2 extends through inverters 14 and 22 through voltage converters 12A and 12B.

  Voltage sensor 10B1 measures voltage VBB1 between terminals of battery SB1. Voltage sensor 10B2 measures voltage VBB2 between the terminals of battery SB2. Although not shown, in order to monitor the charging state of the batteries SB1 and SB2 together with the voltage sensors 10B1 and 10B2, a current sensor for detecting a current flowing through each battery is provided. As the batteries SB1 and SB2, for example, a secondary battery such as a lead storage battery, a nickel metal hydride battery, or a lithium ion battery, a large capacity capacitor such as an electric double layer capacitor, or the like can be used.

  Inverter 14 is connected to power supply line PL2 and ground line SL2. Inverter 14 receives the boosted voltage from voltage converters 12A and 12B, and drives motor generator MG1 to start engine 4, for example. Inverter 14 returns the electric power generated by motor generator MG1 by the power transmitted from engine 4 to voltage converters 12A and 12B. At this time, voltage converters 12A and 12B are controlled by control device 30 so as to operate as a step-down circuit.

  Current sensor 24 detects the current flowing through motor generator MG1 as motor current value MCRT1, and outputs motor current value MCRT1 to control device 30.

  Inverter 22 is connected to power supply line PL2 and ground line SL2 in parallel with inverter 14. Inverter 22 converts the DC voltage output from voltage converters 12 </ b> A and 12 </ b> B into a three-phase AC voltage and outputs it to motor generator MG <b> 2 driving wheel 2. Inverter 22 returns the electric power generated in motor generator MG2 to voltage converters 12A and 12B in accordance with regenerative braking. At this time, voltage converters 12A and 12B are controlled by control device 30 so as to operate as a step-down circuit.

  Current sensor 25 detects the current flowing through motor generator MG2 as motor current value MCRT2, and outputs motor current value MCRT2 to control device 30.

  Control device 30 receives torque command values and rotation speeds of motor generators MG1, MG2, voltages VBA, VBB1, VBB2, VLA, VLB, VH, motor current values MCRT1, MCRT2, and start signal IGON. Control device 30 outputs a control signal PWUB for instructing voltage boosting to voltage converter 12B, a control signal PWDB for instructing voltage step-down and a shutdown signal instructing prohibition of operation.

  Control device 30 further provides control signal PWMI1 for instructing inverter 14 to convert a DC voltage, which is the output of voltage converters 12A and 12B, into an AC voltage for driving motor generator MG1, and motor generator MG1. A control signal PWMC1 for performing a regenerative instruction for converting the AC voltage generated in step 1 into a DC voltage and returning it to the voltage converters 12A and 12B is output.

  Similarly, control device 30 converts control signal PWMI2 for instructing inverter 22 to drive to convert DC voltage into AC voltage for driving motor generator MG2, and AC voltage generated by motor generator MG2 to DC voltage. A control signal PWMC2 for performing a regeneration instruction to convert and return to the voltage converters 12A and 12B side is output.

  It can be said that the vehicle 1 is equipped with a charging device 39 for charging the batteries MB, SB1, SB2 from the outside. The charging device 39 includes voltage converters 12A, 12B, voltage sensors 21A, 21B, system main relays SMRB, SMRG, SR2B, SR3G, SR3B, SR3G, charging relays CHRB, CHRG, a charger 42, and a connector. 44. The connector 44 is connected to the commercial power supply 8 via a CCID (Charging Circuit Interrupt Device) relay 46. The commercial power source 8 is, for example, an AC 100V power source.

  The charger 42 converts alternating current into direct current, regulates the voltage, and applies the voltage to the battery. In addition, in order to enable external charging, there are other methods for connecting the neutral point of the stator coils of motor generators MG1 and MG2 to an AC power source, and a method for combining voltage converters 12A and 12B to function as an AC / DC converter. May be used.

FIG. 2 is a circuit diagram showing a detailed configuration of inverters 14 and 22 in FIG.
Referring to FIGS. 1 and 2, inverter 14 includes a U-phase arm 15, a V-phase arm 16, and a W-phase arm 17. U-phase arm 15, V-phase arm 16, and W-phase arm 17 are connected in parallel between power supply line PL2 and ground line SL2.

  U-phase arm 15 includes IGBT elements Q3 and Q4 connected in series between power supply line PL2 and ground line SL2, and diodes D3 and D4 connected in parallel with IGBT elements Q3 and Q4, respectively. The cathode of diode D3 is connected to the collector of IGBT element Q3, and the anode of diode D3 is connected to the emitter of IGBT element Q3. The cathode of diode D4 is connected to the collector of IGBT element Q4, and the anode of diode D4 is connected to the emitter of IGBT element Q4.

  V-phase arm 16 includes IGBT elements Q5 and Q6 connected in series between power supply line PL2 and ground line SL2, and diodes D5 and D6 connected in parallel with IGBT elements Q5 and Q6, respectively. The cathode of diode D5 is connected to the collector of IGBT element Q5, and the anode of diode D5 is connected to the emitter of IGBT element Q5. The cathode of diode D6 is connected to the collector of IGBT element Q6, and the anode of diode D6 is connected to the emitter of IGBT element Q6.

  W-phase arm 17 includes IGBT elements Q7 and Q8 connected in series between power supply line PL2 and ground line SL2, and diodes D7 and D8 connected in parallel with IGBT elements Q7 and Q8, respectively. The cathode of diode D7 is connected to the collector of IGBT element Q7, and the anode of diode D7 is connected to the emitter of IGBT element Q7. The cathode of diode D8 is connected to the collector of IGBT element Q8, and the anode of diode D8 is connected to the emitter of IGBT element Q8.

  An intermediate point of each phase arm is connected to each phase end of each phase coil of motor generator MG1. That is, motor generator MG1 is a three-phase permanent magnet synchronous motor, and one end of each of three coils of U, V, and W phases is connected to the midpoint. The other end of the U-phase coil is connected to a line UL drawn from the connection node of IGBT elements Q3 and Q4. The other end of the V-phase coil is connected to a line VL drawn from the connection node of IGBT elements Q5 and Q6. The other end of the W-phase coil is connected to a line WL drawn from the connection node of IGBT elements Q7 and Q8.

  1 also differs in that it is connected to motor generator MG2, but the internal circuit configuration is the same as that of inverter 14, and therefore detailed description thereof will not be repeated. FIG. 2 shows that the control signals PWMI and PWMC are given to the inverter, but this is for avoiding complicated description. As shown in FIG. 1, separate control signals PWMI1 are used. , PWMC1 and control signals PWMI2 and PWMC2 are input to inverters 14 and 22, respectively.

FIG. 3 is a circuit diagram showing a detailed configuration of voltage converters 12A and 12B in FIG.
1 and 3, voltage converter 12A includes a reactor L1 having one end connected to power supply line PL1A, and IGBT elements Q1, Q2 connected in series between power supply line PL2 and ground line SL2. And diodes D1, D2 connected in parallel to IGBT elements Q1, Q2, respectively.

  Reactor L1 has the other end connected to the emitter of IGBT element Q1 and the collector of IGBT element Q2. The cathode of diode D1 is connected to the collector of IGBT element Q1, and the anode of diode D1 is connected to the emitter of IGBT element Q1. The cathode of diode D2 is connected to the collector of IGBT element Q2, and the anode of diode D2 is connected to the emitter of IGBT element Q2.

  The voltage converter 12B of FIG. 1 is also different from the voltage converter 12A in that it is connected to the power supply line PL1B instead of the power supply line PL1A. However, the internal circuit configuration is the same as that of the voltage converter 12A, and thus detailed description will be made. Does not repeat. FIG. 3 shows that the control signals PWU and PWD are given to the voltage converter, but this is for the purpose of avoiding complicated description. As shown in FIG. PWUA and PWDA and control signals PWUB and PWDB are input to inverters 14 and 22, respectively.

  FIG. 4 is a diagram illustrating the relationship between each system main relay and the operation of the voltage converter during normal sequential charging.

  Referring to FIGS. 1 and 4, first, when the rechargeable battery is master battery MB, system main relays SMRB and SMRG are controlled to be in the ON state, and system main relays SR2B, SR2G, SR3B and SR3G are in the OFF state. Be controlled. Voltage converter 12A is in the upper arm ON state, that is, IGBT element Q1 in FIG. 3 is turned on and IGBT element Q2 is in the OFF state, and voltage converter 12B is in the gate OFF state, that is, both IGBT elements Q1 and Q2 are controlled to be in the OFF state. . This gate OFF state is also referred to as a voltage converter shutdown state.

  Next, when charging the slave battery SB1, the system main relays SMRB, SMRG, SR2B, SR2G are controlled to the ON state, and the system main relays SR3B, SR3G are controlled to the OFF state. Both voltage converters 12A and 12B are controlled to be in a gate OFF state.

  When charging slave battery SB2, system main relays SMRB and SMRG are both controlled to be in an ON state, system main relays SR2B and SR2G are controlled to be in an OFF state, and system main relays SR3B and SR3G are both controlled to be in an ON state. Is done. Both voltage converters 12A and 12B are controlled to be in a gate OFF state.

  When the master battery MB and the slave batteries SB1 and SB2 are sequentially charged, the system main relay and voltage converter operation as shown in FIG. 4 may be switched. However, when the master battery MB and the slave batteries SB1 and SB2 are not large enough for the power consumption of the motor generators MG1 and MG2, the charging state of either the master battery or the slave battery is extremely low. In some cases, the requested power cannot be supplied from the battery, and the engine starts to make up for it, making it impossible to continue EV travel.

  For example, when the rated power of the master battery is 20 kW and the rated power of the slave battery is 20 kW, a load of 40 kW can be driven if both batteries are sufficiently charged. However, in the method of charging the batteries one by one, it becomes impossible to immediately output power from one of the batteries, and it is impossible to continue to output 40 kW. Therefore, the engine is started to supplement this electric power, and electric power is generated by motor generator MG1. That is, in the method of charging one by one, power shortage occurs immediately, and it becomes impossible to continue the EV traveling before all the power charged from the outside is used up. Therefore, it is desirable to change the charging method according to the charging time.

  FIG. 5 is a flowchart for explaining a charging method of charging device 39 controlled by control device 30 of FIG.

  Referring to FIGS. 1 and 5, control device 30 first determines whether or not to charge only for a short time in step S <b> 1 when the process is started. The control device 30 may detect that the charging is performed for a short time by detecting that the driver has previously pressed a button indicating that the charging is performed for a short time (for example, an “equal charging” button). Even if the operation schedule or the like is registered in the control device 30 and the control device 30 detects how much time is left from the charging start time to the departure time, it is determined whether or not the charging is a short time. Good.

Here, a specific example for determining how much time is a short time will be described. First, the amount of charge that can be externally charged per hour is calculated according to the following equation.
Charge amount = 1200 Wh x 80% (charging efficiency) = 960 Wh
That is, 1200 Wh of power can be output from a household outlet, and by multiplying this by 80% of the charging efficiency, it is calculated that 960 W can be charged per hour.

Next, the charging capacity for charging the battery is calculated. When the battery capacity is 1800 Wh, the upper limit state of charge SOC of the battery is 0.8, and the lower limit SOC is 0.2, the charge capacity can be calculated by the following equation.
Charging capacity = 1800 Wh × (0.8−0.2) = 1080 Wh
The power that can be charged per hour is 960 W, and the charging capacity of one battery is 1080 Wh. Therefore, one battery can be charged in approximately one hour. However, since only one battery can be charged, EV traveling cannot be performed. Therefore, a short time is about 1 hour or less in the above example. In other words, a short time means a time that can charge only the charge capacity of one battery among a plurality of batteries.

  If it is determined in step S1 that charging is a short time, the process proceeds to step S2 and equal charging is performed. On the other hand, if it is determined in step S1 that the charging is not short, that is, the charging time is sufficiently long, the process proceeds to step S3, and charging is performed sequentially.

  After charging is performed in step S2 or S3, the process proceeds to step S4 and charging is terminated.

  FIG. 6 is a flowchart showing details of the equal charging process in step S2 of FIG.

  Referring to FIGS. 1 and 6, when the equal charge process is started, comparison is made between the state of charge SOC (MB) of the master battery and the state of charge SOC (SB1) of slave battery SB1 in step S11. If SOC (MB) <SOC (SB1) is satisfied in step S11, the process proceeds to step S12, and if not, the process proceeds to step S13.

  In step S12, converters 12A and 12B are both in an operating state, and only battery MB is charged. At this time, system main relays SMRB, SMRG, SR2B, SR2G are turned on, and system main relays SR3B, SR3G are controlled to be turned off. By also operating converter 12B, it is possible to positively flow the power supplied via charger 42 to voltage converter 12A via feeder line PL2. If the state of charge of slave battery SB1 is extremely higher, power may be output from the slave battery and directed to the charge power to the master battery together with the power from the charger.

  On the other hand, when the process proceeds from step S11 to step S13, voltage converters 12A and 12B are both shut down, that is, both IGBT elements Q1 and Q2 are controlled to be OFF, and only slave battery SB1 is charged.

  Then, after charging for a predetermined time in any one of steps S12 and S13, the process proceeds to step S14, and it is determined whether or not the charged states of the master battery and the slave battery are substantially equal. Specifically, it may be determined that the state of charge of the batteries has become equal because | SOC (MB) −SOC (SB1) | <threshold. If there is still a difference between the charge states of the master battery and the slave battery in step S14, the process returns to step S11, and one of the batteries is charged again.

  On the other hand, if it is determined in step S14 that the charged states of the master battery and the slave battery are substantially equal, the process proceeds to step S15. In step S15, charging is executed with the voltage converter 12B in the shutdown state and the voltage converter 12A in the upper arm ON state. Then, the power input from the power supply 8 via the charger 42 is supplied to the slave battery SB1, and also supplied to the master battery MB via the diode D1 of the voltage converter 12B and the IGBT element Q1 of the voltage converter 12A. . Thus, equal charge is performed on the batteries MB and SB1 in step S16. This equal charging is performed until a predetermined charging time elapses or until charging is interrupted. Then, in step S17, the process moves to the flowchart of FIG. 5, and then the charging ends in step S4.

  FIG. 7 is a flowchart showing details of the sequential charging process in step S3 of FIG.

  Referring to FIGS. 1 and 7, when processing is first started, control device 30 controls converters 12 </ b> A and 12 </ b> B to be in a shutdown state in step S <b> 21 so that only battery SB <b> 1 is charged. Then, the process proceeds to step S22, and it is determined whether or not the state of charge SOC (SB1) of battery SB1 has become equal to or greater than a threshold value. This threshold value is a threshold value for determining completion of charging (full charge).

  Relays SMRB and SMRG are both controlled to be in the ON state during the process of FIG. At this time, system main relays SR2B and SR2G are set to the ON state, and system main relays SR3B and SR3G are set to the OFF state.

  If SOC (SB1) ≧ threshold value is not satisfied in step S22, the process returns to step S21. If satisfied, the process proceeds to step S23. In step S23, system main relays SR2B and SR2G are set to an OFF state, and system main relays SR3B and SR3G are set to an ON state. As a result, the charging target is switched from the slave battery SB1 to the slave battery SB2. In step S24, only battery SB2 is charged. At this time, both voltage converters 12A and 12B remain in the shutdown state.

  In step S25, it is determined whether or not the state of charge of battery SB2 is equal to or greater than a predetermined threshold value. If SOC (SB2) ≧ threshold value is not satisfied in step S25, the process returns to step S24. If satisfied, the process proceeds to step S26.

  In step S26, system main relays SR2B, SR2G, SR3B, SR3G are all controlled to be in an OFF state.

  Subsequently, in step S27, the voltage converter 12A is controlled to the upper arm ON state, and the voltage converter 12B is controlled to the shutdown state. In this state, only the master battery MB is charged. In step S28, it is determined whether or not the state of charge of master battery MB has reached a predetermined threshold value or more.

  If SOC (MB) ≧ threshold value is not satisfied in step S28, the process returns to step S27 and charging is continued. On the other hand, if SOC (MB) ≧ threshold value is established in step S28, the process proceeds to step S29, the control is moved to the flowchart of FIG. 5, and the charging is terminated in step S4.

  The charger is connected to the slave battery side. Auxiliary power during charging of the slave battery (power of ECU including control device 30 and accessories such as air conditioner and audio) is supplied from master battery MB. Since power is taken out from the master battery while the slave battery is being charged, in order to compensate for this carry-out, the master battery MB is finally charged in sequential charging.

FIG. 8 is a flowchart showing a modification of the equal charging process described in FIG.
Referring to FIG. 1 and FIG. 8, when this equal charge process is started, battery MB is transferred to battery MB in step S41 based on charge state SOC (MB) of master battery MB and charge state SOC (SB1) of slave battery SB1. Power distribution P (MB) is determined, and power distribution P (SB1) to slave battery SB1 is determined in step S42. This determination follows the following formula:
P (MB) = SOC (SB1) / (SOC (MB) + SOC (SB1))
P (SB1) = SOC (MB) / (SOC (MB) + SOC (SB1))
This distribution formula is an example. The state of charge of the battery is detected several times before the end of charging, and the charge power is redistributed. At this time, if the charged state of the battery MB is higher than the charged state of the battery SB1, more power is distributed to the battery SB1 than the battery MB, and the charged state of the battery SB1 is more than the charged state of the battery MB. Is higher than the battery SB1, any distribution method may be used as long as it distributes more power to the battery MB than the battery SB1.

  When power distribution is determined in steps S41 and S42, charging is executed in step S43. In step S44, it is determined whether or not a predetermined charging time has elapsed. If the scheduled charging time has not yet elapsed, the process returns to step S41 and charging is executed after power distribution is determined again. Is repeated. On the other hand, if the scheduled charging time has elapsed in step S44, the process proceeds to step S45 and the control is transferred to the flowchart of FIG.

[Other embodiments]
In FIG. 5, whether to perform equal charge or sequential charge is determined depending on whether or not the charge time is short. However, even when it is not determined whether or not the charging time is short, even charging and sequential charging can be used properly.

FIG. 9 is a flowchart for explaining charge control in another embodiment.
Referring to FIG. 9, when the process is started, it is determined in step S51 whether it is within a predetermined time from the start of charging. The predetermined time is a time corresponding to the “short time” determined in step S1 of FIG. If it is still within the predetermined time, the process proceeds to step S52, the equal charge is executed, and the determination in step S51 is performed again. The equal charging process in step S52 is performed according to the flowchart of FIG. 6 or FIG.

  On the other hand, if it is not within the predetermined time from the start of charging in step S51, that is, after the predetermined time has elapsed, the process proceeds to step S53, and charging is performed sequentially. The sequential charging process in step S53 is performed according to the flowchart shown in FIG. When the charging is completed for all the batteries, the process proceeds to step S54 and the charging is completed.

  Here, in the process of the flowchart of FIG. 9, it is not necessary to first grasp the charging time, and when charging is interrupted in a short time, only equal charging is performed and charging is interrupted. On the other hand, when the charging is not interrupted and the charging is continuously performed for a long time, the charging is sequentially performed after a certain time.

  For example, equal charge is performed until both the master battery MB and the slave battery SB1 reach 50%, and thereafter, the slave batteries SB1 and SB2 and the master battery MB are sequentially charged in this order.

  Finally, the present embodiment will be summarized with reference to FIG. The vehicle power supply system of the present embodiment includes a master battery MB, a slave battery SB1, a charging device 39 for charging the master battery MB and the slave battery SB1 from the outside of the vehicle, and a control device that controls the charging device 39. 30. When charging time for charging master battery MB and slave battery SB1 from the outside of the vehicle is within a predetermined time, control device 30 ensures that charging states SOC of master battery MB and slave battery SB1 are equal. The charging device 39 is controlled so as to perform equal charging for charging. Control device 30 controls charging device 39 so that slave battery SB1 and master battery MB are sequentially charged when the charging time exceeds a predetermined time. For example, when the charging time exceeds a predetermined time, control device 30 charges slave battery SB1 without charging master battery MB until slave battery SB1 reaches a predetermined charging state. After SB1 reaches a predetermined charging state, charging device 39 is controlled to sequentially charge slave battery SB1 without charging master battery MB. Note that the order of sequential charging may be the order of the master battery and the slave battery.

  Preferably, when charging the master battery MB and the slave battery SB1 from the outside of the vehicle using the charging device 39, the control device 30 causes the charging device 39 to perform equal charging from the start of charging to a predetermined time. After the charging is performed for a predetermined time from the start, the charging device 39 sequentially performs the charging.

  Preferably, when charge state of master battery MB and slave battery SB1 is different at the start of equal charge, control device 30 has a low charge state among master battery MB and slave battery SB1 so that the charge states are substantially equal. The charging device 39 is controlled so that charging is performed only in one direction.

  Preferably, when the charging states of master battery MB and slave battery SB1 are different at the start of equalization charging, control device 30 preferably controls each of master battery MB and slave battery SB1 as shown in the flowchart of FIG. According to the state of charge, the distribution of the charge power is determined so that the charge power to the lower charge state of the master battery MB and the slave battery SB1 is larger than the charge power to the higher charge state.

  Preferably, charging device 39 is provided between master battery MB and inverters 14 and 22 as electric loads, and performs voltage conversion between voltage converter 12A and slave battery SB1 and inverters 14 and 22 as electric loads. Voltage converter 12B that performs voltage conversion, and a charger 42 that is connected to a path that electrically connects slave battery SB1 and voltage converter 12B, and that supplies power received from a power source external to the vehicle to the path.

  More preferably, the vehicle power supply system further includes a slave battery SB2 provided in parallel with slave battery SB1 with respect to voltage converter 12B. Charging device 39 further includes system main relays SR2B, SR2G, SR3B, SR3G that select one of slave batteries SB1, SB2 and connect to voltage converter 12B. Charger 42 is connected between relays SR2B, SR2G, SR3B, SR3G and voltage converter 12B.

  As described above, in the vehicle power supply system of the present embodiment, the EV travel distance can be extended as much as possible even when the charging time can be taken only for a short time.

  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 a circuit diagram showing a configuration of a vehicle 1 on which a vehicle power supply system is mounted. It is a circuit diagram which shows the detailed structure of the inverters 14 and 22 of FIG. It is a circuit diagram which shows the detailed structure of the voltage converters 12A and 12B of FIG. It is the figure which showed the relationship between each system main relay and the operation | movement of a voltage converter at the time of normal sequential charge. 4 is a flowchart for explaining a charging method of charging device 39 controlled by control device 30 in FIG. 1. It is the flowchart which showed the detail of the equal charge process in step S2 of FIG. It is the flowchart which showed the detail of the sequential charging process in step S3 of FIG. It is the flowchart which showed the modification of the equal charge process demonstrated in FIG. It is a flowchart for demonstrating control of charge in another Example.

Explanation of symbols

  1 vehicle, 2 wheels, 3 power split mechanism, 4 engine, 6 DC / DC converter, 7 auxiliary machine, 8 commercial power supply, 10A, 10B1, 10B2, 13, 21A, 21B voltage sensor, 12A, 12B voltage converter, 14, 22 Inverter, 15 U-phase arm, 16 V-phase arm, 17 W-phase arm, 24, 25 Current sensor, 30 Control device, 39 Charging device, 40 Air conditioner, 42 Charger, 44 Connector, 46 CCID relay, C1, C2, CH smoothing capacitor, CHRB, CHRG relay, D1-D8 diode, L1 reactor, MB, SB1, SB2 battery, MG1, MG2 motor generator, PL1A, PL1B power line, PL2 power supply line, Q1-Q8 IGBT element, SL1, SL2 Ground line, SMRB SMRG, SR2B, SR3G, SR3B, SR3G system main relay.

Claims (6)

A first power storage device;
A second power storage device;
A charging device for charging the first and second power storage devices from outside the vehicle;
A control device for controlling the charging device,
When the charging time for charging the first and second power storage devices from outside the vehicle is within a predetermined time, the control device equalizes the state of charge of the first and second power storage devices. If the charging time exceeds the predetermined time, the first power storage device is charged until the second power storage device reaches a predetermined charging state. The second power storage device is charged without performing charging, and after the second power storage device reaches a predetermined charging state, the second power storage device is not charged without charging the second power storage device. A vehicle power supply system that controls the charging device to perform sequential charging.   When charging the first and second charging devices from the outside of the vehicle using the charging device, the control device causes the charging device to perform the equal charge from the start of charging to the predetermined time, 2. The vehicle power supply system according to claim 1, wherein after the charging is performed for a predetermined time from the start of charging, the sequential charging is performed by the charging device.   When the charge state of the first and second power storage devices is different at the start of the equal charge, the control device has a charge state of the first and second power storage devices so that the charge states are substantially equal. The power supply system for a vehicle according to claim 1, wherein the charging device is controlled so that charging is performed only to a lower one.   When the charge state of the first and second power storage devices is different at the start of the equal charge, the control device determines the first and second power storage devices according to the state of charge of each of the first and second power storage devices. The charging power is distributed so that the charging power to the lower charging state of the second power storage device is larger than the charging power to the higher charging state of the first and second power storage devices. The power supply system for a vehicle according to any one of claims 1 to 3, which is determined. The charging device is:
A first voltage converter provided between the first power storage device and an electric load for performing voltage conversion;
A second voltage converter provided between the second power storage device and the electric load for performing voltage conversion;
A charger connected to a path that electrically connects the second power storage device and the second voltage converter, and that supplies power received from a power source outside the vehicle to the path. The vehicle power supply system according to claim 1. A third power storage device provided in parallel with the second power storage device with respect to the second voltage converter;
The charging device is:
A relay that selects one of the second and third power storage devices and connects to the second voltage converter;
The vehicle power supply system according to claim 5, wherein the charger is connected between the relay and the second voltage converter on the path.

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