JP2010136553A - Power supply system and electric vehicle loaded therewith - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply system including a plurality of sets of power storage devices and power converters in which and an upper-arm on fixing mode is introduced for improvement in efficiency while overcharging or overdischarging the power storage devices is reliably prevented. <P>SOLUTION: In the power supply system including the plurality of sets of power storage devices and power converters, the upper-arm on fixing mode is completed based on a current integration value output to the power storage device in the upper-arm on fixing mode on the converter. Thereby, the upper-arm on fixing mode can be properly completed based on a simple decision means without excessively relying on the accuracy of an SOC estimation value. Then, the upper-arm on fixing mode can be introduced while reliably preventing the power storage devices from being overcharged or overdischarged. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a power supply system and an electric vehicle equipped with the same, and more specifically to a technique for preventing overcharging / overdischarging of a power storage device in a power supply system including a plurality of sets of power storage devices and power conversion devices.

  In recent years, in an electric vehicle such as a hybrid vehicle or an electric vehicle equipped with an electric motor as a driving force source, the capacity of the power storage mechanism has been increased in order to improve the driving performance such as acceleration performance and driving distance. As a technique for increasing the capacity of the power storage mechanism, a configuration in which a plurality of power storage devices are arranged in parallel has been proposed.

  For example, in Japanese Patent Application Laid-Open No. 2008-109840 (Patent Document 1), in a power supply system including a plurality of power storage devices, according to the ratio of dischargeable capacity until the allowable discharge power of each power storage device is limited, Calculate the discharge power distribution ratio of the power storage device, calculate the charge power distribution ratio of the power storage device according to the ratio of the chargeable capacity until the allowable charge power is limited, and distribute these discharge power and charge power Techniques for controlling the converter according to rate are disclosed.

  According to this technique, according to the distribution ratio, each power storage device is charged and discharged evenly. Therefore, it is possible to maximize system performance in a plurality of power storage devices having different charge / discharge characteristics.

Japanese Patent Laying-Open No. 2003-00229 (Patent Document 2) discloses that when the voltage difference between the voltage on the load side of the converter and the voltage on the power storage device is equal to or greater than a predetermined value, the converter is connected between the power lines on the output side of the converter. A power supply system is disclosed that controls a capacitor so that the power stored in the capacitor is charged back to the power storage device.
JP 2008-109840 A JP 2003-00229 A

  In a power supply system including a power storage device, a buck-boost converter may be provided in order to adjust a DC voltage between the power storage device and a load device connected to the power supply system during charge / discharge control. This converter includes, for example, a chopper circuit having a power semiconductor switching element (hereinafter also simply referred to as “switching element”).

  Thus, in a converter including a switching element, power loss (hereinafter also referred to as “switching loss”) occurs due to the on / off operation of each switching element during the power conversion operation. In a power supply system having a plurality of power storage devices as described above, switching loss occurs in each converter, and there is a concern that the efficiency of the entire system may be reduced. In particular, when the input / output power is small and the load is light, the reduction in efficiency due to this switching loss becomes significant.

  At such a light load, when the step-up / step-down operation by the converter is unnecessary, one of the switching elements (upper arm) of the chopper circuit included in one converter among the plurality of converters is turned on. In addition, the other (lower arm) is fixed in the off state, and the remaining converter is charged / discharged to stop the operation, thereby reducing the switching loss (hereinafter referred to as “upper arm on fixed mode”). Is possible).

  However, since the charge / discharge state is not controlled during such an upper arm on-fixed mode, overcharging / over-discharging of the power storage device may occur unless the upper arm on-fixed mode is properly terminated.

  For example, based on an estimated value (absolute value) of the remaining capacity of the power storage device (hereinafter also referred to as “SOC (State of Charge)”), a method of ending the upper arm on fixed mode and shifting to a normal switching operation is available. Conceivable. However, in general, an error occurs in the SOC estimation of the power storage device. Therefore, if the end of the upper arm on-fixing mode is determined excessively depending on the SOC estimation value, the power storage device overload is caused by inappropriately continuing the mode. Charging / over-discharge may occur.

  The present invention has been made to solve such a problem, and an object of the present invention is to reliably overcharge or overdischarge a power storage device in a power supply system including a plurality of sets of power storage devices and a power conversion device. In addition, the upper arm-on-fixed mode is introduced to improve efficiency.

  A power supply system according to the present invention is a power supply system capable of bidirectionally transferring power to and from a load device, and is provided corresponding to a plurality of power storage devices, a plurality of power conversion devices, a control device, and each power storage device. And a current detector for detecting a current input to and output from each power storage device. The power conversion device is connected between a power line connected to the load device and the plurality of power storage devices, respectively, and each of the power converters is bidirectionally connected to the corresponding power storage device and the power line among the plurality of power storage devices. Perform conversion. The control device controls operations of the plurality of power conversion devices. Each power conversion device is connected in parallel with the power semiconductor switching element, with the power semiconductor switching element inserted and connected between the corresponding power storage device and the power line, and the direction from the power storage device toward the power line as the forward direction. Rectifying element. In addition, the control device fixes the power semiconductor switching element in one power conversion device among a plurality of power conversion devices that is started in response to the establishment of the predetermined condition, and the remaining power conversion devices The determination unit for determining the end of the predetermined operation mode for stopping the operation, and the current input / output to / from the power storage device corresponding to one power conversion device with the power semiconductor switching element fixed on are input to the predetermined operation mode. And a detector for detecting a current integrated value integrated from the time. And this determination part complete | finishes this predetermined operation mode based on an electric current integrated value.

  According to the above power supply system, in a power supply system including a plurality of sets of power storage devices and power conversion devices, based on the current integration value of the current input / output of the power storage device during a predetermined operation mode (upper arm on fixed mode), It is possible to end the upper arm on fixed mode. As a result, while the efficiency improvement effect due to the reduction of switching loss in the entire plurality of power conversion devices is high, the upper arm-on fixed mode in which the charge / discharge state cannot be controlled can be appropriately terminated based on simple determination. That is, the upper arm on-fixing mode for improving the efficiency can be introduced after reliably preventing overcharging or overdischarging of the power storage device.

  Preferably, the control device further includes an estimation unit that calculates an estimated remaining capacity value of each power storage device based on a state of each power storage device. Then, in the determination unit, the predetermined operation mode is terminated based on both the current integrated value by the detection unit and the estimated remaining capacity value by the estimation unit.

  With such a configuration, it is possible to determine whether or not to end the upper arm on fixed mode based on both the current integrated value and the estimated remaining capacity value (SOC estimated value) of the power storage device. As a result, it is possible to determine the end of the upper arm-on-fixed mode in consideration of the SOC estimated value in addition to the current integrated value, so that it is possible to further improve the efficiency and reliably prevent overcharge / overdischarge of the power storage device.

  Preferably, the determination unit ends the predetermined operation mode based on a comparison between the current integrated value and the predetermined reference value, and makes the reference value variable according to the remaining capacity estimated value at the start of the predetermined operation mode. .

  With such a configuration, it is possible to determine the end of the upper arm on fixed mode by a simple determination method of comparing the current integration value with a predetermined reference value. Further, this reference value can be made variable according to the estimated SOC value at the start of the upper arm on fixed mode. In general, when the SOC value is small (that is, close to a fully discharged state), or the SOC value is large (that is, close to a fully charged state), the estimated SOC value is relatively error-free and highly reliable. Become. Therefore, by making the current reference value variable according to the SOC estimated value in this way, in the region where the reliability of the SOC estimated value is relatively high, the current reference value has a margin and the upper arm on fixed mode is continued. By doing so, it becomes possible to reduce switching loss.

  Alternatively, preferably, when the power storage device corresponding to one power conversion device in which the power semiconductor switching element is fixed to be on is charged, the determination unit relatively decreases the reliability of the remaining capacity estimated value. In the case of the first area defined in advance corresponding to the remaining capacity area, the predetermined operation mode is terminated based on the current integral value, while the predetermined operation is performed when the remaining capacity estimation value is smaller than the first area. Continue mode.

  With this configuration, when the power storage device is charged, the estimated SOC value is set to ON in the predetermined first region where the SOC reliability is relatively lowered, using the integrated value of the charge / discharge current. While performing the end determination of the fixed mode, when the estimated SOC value is smaller than the first region, the upper arm on fixed mode can be continued. As a result, at the time of charging, in the first region including the region where the reliability of the SOC estimation value is low, priority is given to prevention of overcharging, while the reliability of the SOC estimation value is relatively high and sufficient for charging power. In a region where there is a margin, priority can be given to reduction of switching loss.

  Preferably, the determination unit relatively decreases the reliability of the remaining capacity estimation value when the power storage device corresponding to one power conversion device in which the power semiconductor switching element is fixed on is discharged. In the case of the second region defined in advance corresponding to the remaining capacity region, the predetermined operation mode is terminated based on the current integration value, while the predetermined operation is performed when the remaining capacity estimation value is larger than the second region. Continue mode.

  With this configuration, when the power storage device is discharged, the estimated SOC value is set to ON in the predetermined second region where the SOC reliability is relatively lowered, using the integrated value of the charge / discharge current. While performing the end determination of the fixed mode, when the estimated SOC value is larger than the second region, the upper arm on fixed mode can be continued. As a result, at the time of discharging, in the second region including the region where the reliability of the SOC estimation value is low, the reliability of the SOC estimation value is relatively high and sufficient for the discharge power while giving priority to the prevention of overcharge. In a region where there is a margin, priority can be given to reduction of switching loss.

  Preferably, when the power storage device corresponding to one power conversion device in which the power semiconductor switching element is fixed to be on is charged, the determination unit has a predetermined third value in which the remaining capacity estimation value is set as a charge limit of the power storage device. When the value rises above the remaining capacity reference value, the predetermined operation mode is terminated regardless of the current integrated value.

  By adopting such a configuration, at the time of charging, if the estimated SOC value exceeds a predetermined management upper limit value set as the charging limit of the power storage device, the upper arm on fixed mode can be terminated. Thus, overcharging of the power storage device can be prevented more reliably.

  Preferably, the determination unit is configured to perform a predetermined fourth operation in which the estimated remaining capacity is set as a discharge limit of the power storage device when the power storage device corresponding to one power conversion device having the power semiconductor switching element fixed on is discharged. When the remaining capacity is lower than the reference value, the predetermined operation mode is terminated regardless of the current integrated value.

  With such a configuration, at the time of discharging, if the estimated SOC value exceeds a predetermined control lower limit value set as the discharge limit of the power storage device, the upper arm on fixed mode can be terminated. In addition, overdischarge of the power storage device can be prevented more reliably.

  Preferably, the power supply system further includes a voltage detector that detects a voltage of electric power input / output to / from the load device, and the determination unit has a change amount of the voltage detected by the voltage detector per predetermined time. When the predetermined voltage change amount reference value is exceeded, the predetermined operation mode is terminated regardless of the current integrated value.

  With such a configuration, when an abrupt change in charge / discharge voltage occurs, the upper arm on-fixed mode can be terminated based on the amount of change in the voltage. Discharge can be prevented more reliably.

  Preferably, the electric vehicle includes a load device and the power supply system, and the load device is connected between the rotating electrical machine configured to generate a driving force, the power line and the rotating electrical machine, and the power line. And an inverter device configured to perform power conversion bidirectionally between the rotary electric machine and the rotating electrical machine.

  With such a configuration, in an electric vehicle equipped with the power supply system as described above, for example, when a gentle slope uphill or downhill road continues, that is, a small amount of charge / discharge power is continuously input / output. In such a case, it is possible to improve the efficiency of the power conversion device by introducing the upper arm on-fixing mode after reliably preventing overcharge or overdischarge of the power storage device.

  According to the present invention, in a power supply system including a plurality of sets of power storage devices and power conversion devices, an upper arm on-fixing mode for improving efficiency is introduced after reliably preventing overcharge or overdischarge of the power storage devices. Is possible.

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

[Embodiment 1]
FIG. 1 is an overall block diagram of an electric vehicle 100 according to the embodiment of the present invention. Note that the configuration of the electric vehicle 100 is not particularly limited as long as the electric vehicle 100 can travel with electric power from the chargeable power storage device. Electric vehicle 100 includes, for example, a hybrid vehicle, an electric vehicle, and a fuel cell vehicle.

Referring to FIG. 1, electrically powered vehicle 100 includes a power supply system 80 and a load device 90.
Load device 90 includes inverters 20-1, 20-2, motor generators MG 1, MG 2, engine 2, power split mechanism 4, and wheels 6. In FIG. 1, a hybrid vehicle including the engine 2 will be described as an example of the electric vehicle 100, but the arrangement of the engine 2 is omitted in the case of an electric vehicle and a fuel cell vehicle.

  Inverters 20-1 and 20-2 are connected in parallel to main positive bus MPL and main negative bus MNL. Inverters 20-1 and 20-2 convert drive power (DC power) supplied from main positive bus MPL and main negative bus MNL into AC power based on drive signals PWI1 and PWI2 from ECU 30. Output to motor generators MG1 and MG2, respectively. Inverters 20-1 and 20-2 convert AC power generated by motor generators MG1 and MG2 into DC power, respectively, and output the power as regenerative power to main positive bus MPL and main negative bus MNL.

  Motor generators MG1 and MG2 receive AC power supplied from inverters 20-1 and 20-2, respectively, and generate rotational driving force. In addition, motor generators MG1 and MG2 receive rotational force from the outside and generate AC power. Motor generators MG1 and MG2 are made of, for example, a three-phase AC rotating electric machine including a rotor having a permanent magnet embedded therein and a stator having a Y-connected three-phase coil. Motor generators MG 1 and MG 2 are connected to power split mechanism 4, and the rotational driving force is transmitted to wheels 6 through a drive shaft further connected to power split mechanism 4.

  Motor generators MG1 and MG2 are also coupled to engine 2 via power split mechanism 4. Then, control is executed by ECU 30 so that the driving force generated by engine 2 and the driving force generated by motor generators MG1, MG2 have an optimal ratio. Alternatively, either one of motor generators MG1 and MG2 may function exclusively as an electric motor, and the other motor generator may function exclusively as a generator.

  The power supply system 80 includes power storage devices 15-1, 15-2, converters 10-1, 10-2, an ECU 30, voltage sensors 40-1, 40-2, 46, and current sensors 50-1, 50-. 2, temperature sensors 60-1 and 60-2, and a smoothing capacitor C.

  The power storage devices 15-1 and 15-2 are power storage elements configured to be chargeable / dischargeable. The power storage devices 15-1 and 15-2 are configured by, for example, a secondary battery such as a lithium ion battery or a nickel metal hydride battery, or a power storage element such as an electric double layer capacitor. Power storage device 15-1 is connected to converter 10-1 by positive electrode line PL1 and negative electrode line NL1, and power storage device 15-2 is connected to converter 10-2 by positive electrode line PL2 and negative electrode line NL2.

  Converters 10-1 and 10-2 are connected in parallel to main positive bus MPL and main negative bus MNL. Converter 10-1 performs power conversion between power storage device 15-1 and main positive bus MPL and main negative bus MNL based on drive signals PWC1, UA1, SD1 from ECU 30. Converter 10-2 performs power conversion between power storage device 15-2 and main positive bus MPL and main negative bus MNL based on drive signals PWC2, UA2, SD2 from ECU 30.

  Current sensors 50-1 and 50-2 detect current Ib1 input to and output from power storage device 15-1, and current Ib2 input to and output from power storage device 15-2, respectively, and detect the detected values as ECU 30. Output to. Each of current sensors 50-1 and 50-2 detects a current (discharge current) output from the corresponding power storage device as a positive value and a current (charge current) input to the corresponding power storage device as a negative value. Shall be detected. FIG. 1 shows a case where each of the current sensors 50-1 and 50-2 detects the current of the positive line. However, each of the current sensors 50-1 and 50-2 detects the current of the negative line. May be.

  Voltage sensors 40-1 and 40-2 detect voltage Vb1 of power storage device 15-1 and voltage Vb2 of power storage device 15-2, respectively, and output the detected values to ECU 30. Temperature sensors 60-1 and 60-2 detect temperature T1 of power storage device 15-1 and temperature T2 of power storage device 15-2, respectively, and output the detected values to ECU 30.

  Smoothing capacitor C is connected between main positive bus MPL and main negative bus MNL, and reduces voltage fluctuation components contained in main positive bus MPL and main negative bus MNL. Voltage sensor 46 detects voltage VH between main positive bus MPL and main negative bus MNL, and outputs the detected value to ECU 30.

  ECU 30 generates signals PWC1, SD1, and UA1 for controlling converter 10-1, and outputs any signal selected according to the state of the load device to converter 10-1. ECU 30 also generates signals PWC2, SD2 and UA2 for controlling converter 10-2, and outputs any one of signals to converter 10-2.

  ECU 30 also receives an input of power (hereinafter also referred to as “required power”) PR required for the power supply system for driving the load device. For example, the required power PR is calculated by a vehicle ECU (not shown) that integrally controls the entire electric vehicle 100 based on the accelerator pedal opening, the vehicle speed, and the like.

  Further, ECU 30 generates signals PWI1 and PWI2 for driving inverters 20-1 and 20-2, respectively, and outputs the generated signals PWI1 and PWI2 to inverters 20-1 and 20-2, respectively.

  Although not shown, the ECU 30 includes a CPU (Central Processing Unit), a storage device, and an input / output buffer. The ECU 30 inputs each sensor and outputs a control command to each device. Control each device. Note that these controls are not limited to processing by software, and a part of them can be constructed and processed by dedicated hardware (electronic circuit).

FIG. 2 shows a configuration of converters 10-1 and 10-2 shown in FIG.
Referring to FIG. 2, converter 10-1 includes power semiconductor switching elements Q1A and Q1B, diodes D1A and D1B, a reactor L1, and a smoothing capacitor C1.

  In this embodiment, an IGBT (Insulated Gate Bipolar Transistor) is applied as the switching element. However, any switching element can be applied as long as the on / off can be controlled by the control signal. For example, a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or a bipolar transistor can be used.

  Switching elements Q1A and Q1B are connected in series between positive bus LN1A connected to main positive bus MPL and negative bus LN1C connected to main negative bus MNL, and are shown in accordance with signals of PWC1, SD1 and UA1 from ECU 30. ON / OFF operation through a driver circuit that does not. Diodes D1A and D1B are connected in antiparallel to switching elements Q1A and Q1B, respectively. Reactor L1 has one end connected to a connection node of switching elements Q1A and Q1B, and the other end connected to positive line LN1B connected to positive line PL1. Smoothing capacitor C1 is connected between positive line LN1B and negative bus LN1C connected to negative line NL1, and reduces the AC component included in the DC voltage between positive line LN1B and negative bus LN1C.

  Converter 10-1 includes chopper circuit 11-1. Converter 10-1 is basically controlled such that switching elements Q1A and Q1B are turned on and off in a complementary manner in accordance with a signal PWC1 from ECU 30 within each switching period. During the step-up operation, converter 10-1 converts DC voltage Vb1 supplied from power storage device 15-1 into DC voltage VH (this DC voltage corresponding to the input voltage to inverters 20-1 and 20-2) Voltage "). This step-up operation is performed by supplying the electromagnetic energy accumulated in reactor L1 during the ON period of switching element Q1A to positive bus LN1A via switching element Q1B and antiparallel diode D1B.

  Converter 10-1 steps down DC voltage VH to DC voltage Vb1 during the step-down operation. This step-down operation is performed by supplying the electromagnetic energy accumulated in reactor L1 during the ON period of switching element Q1B to negative bus LN1C via switching element Q1A and antiparallel diode D1A. The voltage conversion ratio (ratio of VH and Vb1) in these step-up and step-down operations is controlled by the on-period ratio (duty ratio) of the switching elements Q1A and Q1B in the switching period. If switching elements Q1A and Q1B are fixed to OFF and ON, respectively, VH = Vb1 (voltage conversion ratio = 1.0) can be obtained.

  Further, in converter 10-1, switching element Q1B of the upper arm is fixed to on and switching element Q1A of the lower arm is fixed to off in accordance with signal UA1 from ECU 30. Such an operation enables input / output of charge / discharge power from the power storage device 15-1 while reducing switching loss.

  In converter 10-1, both switching elements Q1B and Q1A of the upper and lower arms are fixed off in accordance with signal SD1 from ECU 30. Thereby, the input / output of charge / discharge power from power storage device 15-1 can be stopped.

  Converter 10-2 has the same configuration as converter 10-1. In converter 10-1, switching elements Q1A and Q1B are replaced with switching elements Q2A and Q2B, diodes D1A and D1B are replaced with diodes D2A and D2B, reactor L1 is replaced with reactor L2, and smoothing capacitor C1 is replaced with smoothing capacitor C2. Replacement, positive bus LN1A, negative bus LN1C, positive line LN1B are replaced with positive bus LN2A, negative bus LN2C, positive line LN2B, positive line PL1, negative line NL1 are replaced with positive line PL2, negative line NL2, respectively, and chopper circuit The configuration obtained by replacing 11-1 with the chopper circuit 11-2 is the configuration of the converter 10-2.

  FIG. 3 is a control block diagram of ECU 30 shown in FIG. Referring to FIG. 3, ECU 30 includes a converter control unit 200 and an inverter control unit 110.

  Converter control unit 200 receives voltage Vb1 detected by voltage sensor 40-1, voltage VH detected by voltage sensor 46, and current Ib1 detected by current sensor 50-1, and based on these, converter 10- A PWM (Pulse Width Modulation) signal PWC1 for turning on / off one switching element Q1A, Q1B is generated. In addition, shutdown signal SD1 for stopping converter 10-1 and upper arm on signal UA1 for fixing switching elements Q1A and Q1B to off and on, respectively, are generated.

  Converter control unit 200 selectively outputs one of PWM signal PWC1, shutdown signal SD1, and upper arm on signal UA1 to converter 10-1 in accordance with the operation mode selected according to the state of the load device. .

  Similarly, converter control unit 200 receives voltage Vb2 detected by voltage sensor 40-2, voltage VH detected by voltage sensor 46, and current Ib1 detected by current sensor 50-2, based on these. PWM signal PWC2 for turning on / off switching elements Q2A and Q2B of converter 10-2 is generated. Further, a shutdown signal SD2 for stopping converter 10-2 and upper arm on signal UA2 for fixing switching elements Q2A and Q2B to on and off, respectively, are generated.

  Converter control unit 200 selectively outputs one of PWM signal PWC2, shutdown signal SD2, and upper arm on signal UA2 to converter 10-2 in accordance with the operation mode selected according to the state of the load device. .

  Inverter control unit 110 is included in inverters 20-1 and 20-2 based on torque command values TR1 and TR2 of motor generators MG1 and MG2, motor currents MCRT1 and MCRT2, rotor rotation angles θ1 and θ2, and voltage VH. PWM signals PWI1 and PWM2 for turning on / off the power semiconductor switching element are generated, and the generated PWI1 and PWM2 are output to inverters 20-1 and 20-2.

  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).

  Next, control of converters 10-1 and 10-2 in converter control unit 200 shown in FIG. 3 will be described using FIG. FIG. 4 is a functional block diagram illustrating voltage / current control of converters 10-1 and 10-2.

  Referring to FIG. 4, converter control unit 200 (FIG. 3) includes a target value setting unit 210, a voltage control unit 215-1 and a current control unit 215-2. In the example of FIG. 4, during normal control, converter 10-1 is voltage controlled to control system voltage VH to target voltage VR, while converter 10-2 is current controlled and corresponding power storage device 15-2 is controlled. The charge / discharge current is controlled to the target current IR.

  Target value setting unit 210 includes torques of motor generators MG1 and MG2 (typically torque command values TR1 and TR2) and rotation speeds MRN1 and MRN2 (command values or detection values based on detection of rotation angles θ1 and θ2). Based on SOC1 and SOC2 of power storage devices 15-1 and 15-2, target voltage VR of the voltage controlled converter and target current IR of the current controlled converter are generated.

  Target value setting unit 210 applies system voltage VH according to torque command values TR1, TR2 and rotational speeds MRN1, MRN2 of motor generators MG1, MG2 during power running operation and regenerative braking of motor generators MG1 and / or MG2. Is set to an appropriate level. For example, the target voltage VR is set by a preset map. In general, separate maps are set for motor generators MG1 and MG2, and the maximum value of the target voltage set by each map is set as the target voltage VR of the entire system. In addition, target current IR is preferably set in consideration so that the SOC between power storage devices 15-1 and 15-2 is balanced.

  Voltage control unit 215-1 includes subtraction units 222-1 and 226-1, PI control unit 224-1, and modulation unit 228-1. Subtraction unit 222-1 subtracts system voltage VH from target voltage VR and outputs the calculation result to PI control unit 224-1. The PI control unit 224-1 performs a proportional integration calculation with the deviation between the target voltage VR and the system voltage VH as an input, and outputs the calculation result to the subtraction unit 226-1.

  Subtraction unit 226-1 subtracts the output of PI control unit 224-1 from the inverse of the theoretical boost ratio of converter 10-1 indicated by voltage Vb1 / target voltage VR, and uses the calculation result as duty command Ton1 to modulation unit 228. Output to -1. Modulator 228-1 generates PWM signal PWC1 based on duty command Ton1 and a carrier wave (carrier wave) generated by an oscillating unit (not shown).

  Current control unit 215-2 includes subtraction units 222-2 and 226-2, PI control unit 224-2, and modulation unit 228-2. Subtraction unit 222-2 subtracts current Ib2 from target current IR, and outputs the calculation result to PI control unit 224-2. The PI control unit 224-2 performs a proportional integration calculation with the deviation between the target current IR and the current Ib2 as an input, and outputs the calculation result to the subtraction unit 226-2.

  Subtraction unit 226-2 subtracts the output of PI control unit 224-2 from the inverse of the theoretical step-up ratio of converter 10-2 indicated by Vb2 / VR, and uses the calculation result as duty command Ton2 to modulation unit 228-2. Output. Modulation section 228-2 generates PWM signal PWC2 based on duty command Ton2 and a carrier wave (carrier wave) generated by an oscillation section (not shown).

  When the system voltage VH is lower than the target voltage VR, and when the reciprocal of the theoretical boost ratio (Vb1 / VR) is reduced, the voltage control unit 215-1 sets the on-period ratio of the lower arm element (Q1A) to The PWM signal PWC1 is generated so as to increase (or the OFF period ratio of the upper arm element (Q1B) increases).

  On the other hand, current control unit 215-2 has a lower arm element when output current Ib2 from power storage device 15-2 is lower than target current IR and when the inverse of the theoretical boost ratio (Vb2 / VR) increases. The PWM signal PWC2 is generated so that the ON period ratio of (Q2A) increases.

  It is noted that current control unit 215-2 charges current Ib2 (Ib2 <0) rather than target current IR when power storage device 15-2 is charged, that is, when target current IR is set to a negative value (IR <0). ) Is low (| IR | <| Ib2 |, that is, when the charging current is excessive), the PWM signal PWC2 is generated so that the ON period ratio of the upper arm element (Q2B) decreases. On the contrary, when the charging current is insufficient (when IR <Ib2, that is, when | IR |> | Ib2 |), the PWM signal PWC2 is generated so that the ON period ratio of the upper arm element (Q2B) is increased.

  With the control configuration shown in FIG. 4, voltage control of converter 10-1 and current of converter 10-2 by switching (on / off) operation of upper arm elements Q1B and / or Q2B and lower arm elements Q1A and / or Q2A By control, the system voltage VH and the charge / discharge balance of the power storage devices 15-1 and 15-2 can be controlled.

  Thereby, in the power supply system of the present embodiment, during the power running operation, the electric power discharged from power storage devices 15-1 and 15-2 is converted into system voltage VH as the input voltage of the load device, and the power supply wiring ( The power conversion operation is performed so as to output to the main positive bus MPL). On the other hand, at the time of regenerative braking operation, power conversion operation is performed so that power storage devices 15-1 and 15-2 are charged by charging power on power supply wiring (main positive bus MPL).

  FIG. 4 shows a configuration example in which voltage control is executed by converter 10-1 while current control is executed by converter 10-2. However, voltage control and current control are executed by any converter. These can be switched. For example, a converter that performs voltage control / current control can be switched in accordance with the SOC of power storage devices 15-1 and 15-2.

  FIG. 5 is a functional block diagram illustrating the configuration of operation mode control of converters 10-1 and 10-2 by converter control unit 200 shown in FIG.

  Referring to FIG. 5, converter control unit 200 (FIG. 3) includes voltage / current control unit 220-1 for controlling converter 10-1, upper arm ON instruction unit 230-1, and shutdown instruction unit 235. -1 and an instruction selection unit 240-1.

  Further, converter control unit 200 includes voltage / current control unit 220-2 for controlling converter 10-2, upper arm ON instruction unit 230-2, shutdown instruction unit 235-2, and instruction selection unit 240-. 2, an SOC estimation unit 270 that estimates the SOC of power storage devices 15-1 and 15-2, a determination unit 250, a mode selection unit 260, and a detection unit 280.

  The voltage / current control unit 220-1 is configured by, for example, one of the voltage control unit 215-1 and the current control unit 215-2 shown in FIG. 4, and performs voltage control according to the target voltage VR or the target current IR. PWM signal PWC1 for current control is generated. Upper arm ON instructing unit 230-1 generates an upper arm on signal UA1 for fixing upper arm of converter 10-1.

  Shutdown instruction unit 235-1 outputs a shutdown signal SD1 for stopping the operation of converter 10-1.

  In accordance with mode control signal MS1 from mode selection unit 260, instruction selection unit 240-1 outputs one of PWM signal PWC1, upper arm on signal UA1, and shutdown signal SD1 to converter 10-1.

  Similarly, voltage / current control unit 220-2 is configured by, for example, one of voltage control unit 215-1 and current control unit 215-2 shown in FIG. 4, and performs voltage control or target current according to target voltage VR. A PWM signal PWC2 for current control according to IR is generated. Upper arm ON instruction unit 230-2 generates upper arm on signal UA2 for fixing converter 10-2 to the upper arm on state.

  Shutdown instruction unit 235-2 outputs a shutdown signal SD2 for stopping the operation of converter 10-2.

  In accordance with mode control signal MS2 from mode selection unit 260, instruction selection unit 240-2 outputs one of PWM signal PWC2, upper arm on signal UA2, and shutdown signal SD2 to converter 10-2.

  The SOC estimation unit 270 includes voltages Vb1 and Vb2 detected by the voltage sensors 40-1 and 40-2, Ib1 and Ib2 detected by the current sensors 50-1 and 50-2, and temperature sensors 60-1 and 60-2. Based on the temperatures T1, T2 and the like detected in step S1, the SOCs 1, SOC2 of the power storage devices 15-1, 15-2 are calculated and output to the determination unit 250. For example, the SOC 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. The SOC1 (SOC2) can be calculated by various known methods using the voltage Vb1 (Vb2), the current Ib1 (or Ib2), the temperature T1 (or T2), and the like.

  Mode selection unit 260 is set by required power PR required for the power supply system for driving load devices (inverters 20-1, 20-2 and motor generators MG1, MG2) and target value setting unit 210. The operation mode of converters 10-1 and 10-2 is selected based on the target voltage VR. Specifically, mode selection unit 260 turns on the “voltage / current control mode” in which one of converters 10-1 and 10-2 is voltage controlled and the other is current controlled, or the upper arm switching element of one converter. One of the “upper arm on fixed modes” is selected in which the operation of the other converter is stopped while being set to fixed. The upper arm-on-fixed mode is basically selected under any condition within a range in which charging / discharging can be performed with one power storage device and boosting / lowering is not required.

  More specifically, the mode selection unit 260 selects the PWC1 and PWC2 and outputs them to the inverters 20-1 and 20-2 when the “voltage / current control mode” is selected. Mode control signals MS1 and MS2 are output to -2. In addition, when “upper arm on fixed mode” is selected, mode selection unit 260 selects a converter to be fixed on upper arm based on the states of power storage devices 15-1 and 15-2 such as voltages Vb 1 and 2 and SOCs 1 and 2. To do. Then, the mode selection unit 260 controls the mode so that the upper arm on signal UA (which generally represents UA1 and UA2) is selected for the instruction selection unit on the converter side selected to be fixed to the upper arm on. Set the signal. On the other hand, the mode control signal is set so that the shutdown signal SD (which generally indicates SD1 and SD2) is selected for the instruction selection unit on the other converter side.

  Further, when the upper arm on end signal CSTP input from the determination unit 250 is turned on while the upper arm on fixed mode is selected, the mode selection unit 260 ends the upper arm on fixed mode and sets the “voltage / current control mode”. Mode control signals MS1 and MS2 are set so as to be selected.

Detection unit 280 receives inputs of Ib 1 and Ib 2 detected by current sensors 50-1 and 50-2 and mode control signals MS 1 and MS 2 from mode selection unit 260. Then, when any of the mode control signals MS1 and MS2 is in the upper arm on fixed mode, the detection unit 280
A current integrated value ΣIb from the start of the upper arm on fixed mode of the current input to and output from the power storage device corresponding to the converter in the upper arm on fixed mode is detected. Then, the current integration value ΣIb is output to the determination unit 250.

  More specifically, by detecting the current integration value ΣIb at a predetermined time, the detection unit 280 can calculate the charge / discharge amount input / output from the power storage device. Then, it is possible to calculate the change amount of the SOC from the calculated charge / discharge amount and the rated capacity of the power storage device. Further, in the upper arm on fixed mode, the voltage when charging / discharging is almost constant, so the charge / discharge power is calculated from the detected current integration value ΣIb and the voltage Vb of the power storage device being charged / discharged. It is also possible to do. That is, the current integrated value ΣIb detected above can be considered to reflect the amount of change in SOC of the power storage device and the charge / discharge power during the actual charge / discharge operation. Therefore, in the present embodiment, the end determination of the upper arm on fixed mode is performed based on the current integration value ΣIb, but this is determined based on the amount of change in the SOC when the SOC estimation is performed based on the current Ib. It can be said that this is a concept including performing determination based on actual charge / discharge power. Therefore, it is possible to end the upper arm on fixed mode more accurately and simply by performing the end determination of the upper arm on fixed mode based on the current integration value ΣIb, compared to the case where the SOC estimated value (absolute value) is used. Therefore, it is possible to introduce the upper arm on-fixing mode while reliably preventing overcharging or overdischarging of the power storage device.

  Determination unit 250 includes SOCs 1 and 2 estimated by SOC estimation unit 270, voltage VH detected by voltage sensor 46, current integrated value ΣIb detected by detection unit 280, and mode control signal MS1 from mode selection unit 260. , 2 are received. Then, when any of the mode control signals MS1 and MS2 is in the upper arm on fixed mode, the determination unit 250 determines whether to end the upper arm on fixed mode based on the state of the input signal. . Then, determination unit 250 outputs upper arm on end signal CSTP to mode selection unit 260. The upper arm on end signal CSTP is turned on when the upper arm on fixing mode is terminated in the above determination.

  FIG. 6 shows an example of the relationship between the SOC and voltage of the power storage device. W1 in the figure is an example of a curve representing the relationship between SOC and voltage. Depending on the type of battery included in the power storage device, as shown in FIG. 6, the change in voltage may become smaller with respect to the change in SOC in the middle portion of the SOC (area A <b> 2 in the figure). Therefore, when the SOC is estimated based on the output voltage Vb of the power storage device (Vb1 and Vb2 are collectively indicated), temperature T (T1 and T2 are generally indicated), etc. Even when it is in the state b2 in the middle, there is a possibility that it is estimated as the state b1 in the figure due to a detection error or the like. In such a case, when charging the power storage device, it is estimated that the SOC is smaller than the actual one (there is a margin in the charging power) even though the SOC of the power storage device is actually large. It will be. Therefore, if the end of the upper arm-on-fixed mode is determined based on the SOC estimated value excessively, there is a possibility that power exceeding the actually possible charging power is input and overcharging occurs.

  Therefore, in the first embodiment, as described in the explanation of FIG. 5, as the end determination of the upper arm on fixed mode, by limiting the current integrated value ΣIb, excessive charge / discharge power to the power storage device is increased. Suppress. As a result, it is possible to prevent overcharge / overdischarge in the upper arm on fixed mode.

  FIG. 7 is a flowchart for explaining in detail the termination determination control process in the upper arm on fixed mode shown in the functional block diagram of FIG. Starting with FIG. 7, each step in the flowcharts shown below is realized by executing a program stored in advance in the ECU 30 at a predetermined cycle. Alternatively, for some steps, it is also possible to construct dedicated hardware (electronic circuit) and realize processing.

  Note that FIG. 7 illustrates a case where the power storage device is charged. Further, although this flowchart is individually applied to each converter, FIG. 7 illustrates a case where it is applied to the converter 10-1.

  Referring to FIG. 7, ECU 30 first in step (hereinafter abbreviated as “S”) 400, current Ib1, voltage Vb1, temperature T1, system voltage VH, required power PR, etc. of power storage device 15-1. While acquiring each data, SOC1 is estimated based on the acquired data.

  Next, the ECU 30 sets reference values such as the upper and lower limit values of the SOC and the current integration reference value that are necessary for the determination in S410. Note that the current integration reference value may be set to a predetermined fixed value, or may be set to be variable according to the estimated SOC value at the start of fixing the upper arm on the corresponding power storage device. For example, the current integration reference value may be set to gradually change as the SOC estimated value increases, or is divided into a region where the SOC estimated value is large, a medium region, and a small region, A current integration reference value may be set for each section. By doing this, if the estimated SOC value is small during charging, even if there is some error in the estimated SOC value, there is a sufficient margin in charge power before overcharging. The reduction of the switching loss can be prioritized by setting the current integration reference value large and making the upper arm on fixed period as long as possible.

  Next, in S420, the ECU 30 determines whether or not the upper arm on fixed mode is being selected.

  If it is not the upper arm on fixed mode (NO in S420), that is, if it is the “voltage / current control mode”, the control is shifted to S500, and the ECU 30 continues to select the “voltage / current control mode”. In S490, PWM signal PWC1 is output to converter 10-1.

  On the other hand, when the upper arm on fixing mode is selected (YES in S420), ECU 30 next determines whether or not the converter is the upper arm on fixing target converter based on the states of power storage devices 15-1 and 15-2. Determination is made (S430). Specifically, the determination is made based on comparison between SOC1 and 2 or voltages Vb1 and Vb2.

  If it is not the upper arm-on-fixed converter (NO in S430), the process proceeds to S510, and ECU 30 selects to stop the switching operation of the converter. Then, in S490, ECU 30 outputs shutdown signal SD1 to the converter.

  If the converter is the upper arm on-fixed converter (YES at S430), then at S440, based on the state of charge of the power storage device, the traveling state of the vehicle, and the state of the load device, the upper arm on is fixed. It is determined whether the start condition is satisfied.

  If the upper arm-on fixing start condition is not satisfied (NO in S440), ECU 30 ends the upper arm-on fixing mode, the process proceeds to S500, and the “voltage / current control mode” is selected. ECU 30 then outputs PWM signal PWC1 to converter 10-1 in S490.

  On the other hand, if the start condition for fixing the upper arm on is satisfied (YES in S440), the process proceeds to S450. In S450, whether or not the estimated SOC value of the power storage device corresponding to the converter selected in the upper arm-on-fixed mode estimated in S400 exceeds the SOC upper limit value set as the chargeable management upper limit of the power storage device. Is determined.

  If the estimated SOC value exceeds the above SOC upper limit value (NO in S450), even if there is a slight error in the estimated SOC value and the estimated value is larger than the actual value, more charge is required. It can be said that the possibility of overcharging is very high. Therefore, in such a case, in order to give priority to prevention of overcharge, the process is shifted to S500, and the upper arm on-fixing mode is immediately terminated and the “voltage / current control mode” is selected. ECU 30 then outputs PWM signal PWC1 to converter 10-1 in S490.

  On the other hand, when the estimated SOC value is equal to or lower than the above SOC upper limit value in S450 (YES in S450), the process proceeds to S460 and the regenerative current from inverters 20-1 and 20-2, that is, the stored power. Integration processing of the charging current to the device is performed. Thereby, the current integrated value ΣIb in the upper arm on fixed mode after the upper arm on fixed mode is started can be obtained. In the present embodiment, the charging current is expressed as a negative value as described above.

  Next, in S470, the ECU 30 determines whether or not the absolute value of the current integration value ΣIb processed in S460 exceeds the current integration reference value set in S410.

  If the absolute value of current integration value ΣIb exceeds the current integration reference value (NO in S470), the process proceeds to S500, the upper arm on fixed mode is terminated, and the “voltage / current control mode” is selected. . In S490, PWM signal PWC1 is output to converter 10-1.

  On the other hand, when the absolute value of current integration value ΣIb is equal to or smaller than the current integration reference value (YES in S470), ECU 30 continues to select the upper arm on fixed mode (S480). Then, the upper arm switching element Q1B of the converter 10-1 is fixed on, and the upper arm on signal UA1 is output to the converter 10-1 so that the lower arm switching element Q1A is fixed off (S490). .

  With such a configuration, in the power supply system including a plurality of sets of power storage devices and power conversion devices, it is possible to end the upper arm on-fixing mode of the converter based on the integral value of the charging current. As a result, overcharging can be prevented without depending on the accuracy of the estimated SOC value. In the flowchart of FIG. 7 described above, the above-described effect can be obtained without the step of S450. Further, the same processing as described above is applied to converter 10-2.

  Note that although the case where the power storage device is charged has been described above, the same processing can be performed when the power storage device is discharged. In this case, the integrated value of the current may be determined based on the integrated value of the discharge current from the power storage device instead of the regenerative current. Further, regarding the comparison between the estimated SOC value and the limit value in S450, the upper arm on-fixing mode is terminated when the estimated SOC value is smaller than the lower limit SOC value instead of the upper limit SOC value. That's fine. In addition, the current integration reference value for performing the above determination may be different during charging and discharging.

  Also, even if the upper arm on-fixed mode is terminated and the “voltage / current control mode” is selected once according to the processing of the above flowchart, if the conditions for selecting the upper arm on-fixed mode are established again, At this point, the selection of the upper arm on fixed mode can be resumed. At this time, depending on the state of the power storage device (SOC, voltage, etc.), the same converter as the converter that was previously fixed with the upper arm on may be selected again, or the other converter that was shut down last time is selected with the upper arm on fixed Also good.

[Modification of Embodiment 1]
In the first embodiment described above, the case where the end of the upper arm on fixed mode is always determined by the current integration value ΣIb when the upper arm on condition is satisfied within the SOC upper and lower limit range of the SOC of the power storage device will be described. did.

  In the modification of the first embodiment, a case will be described in which, even if the SOC estimated value is within the SOC upper and lower limit range, the end determination of the upper arm on fixed mode by the current integrated value ΣIb is omitted in consideration of the SOC estimated value. .

  In the case of the first embodiment, in the region where the SOC is relatively small, when the upper arm on-fixed mode is terminated by the charge / discharge power based on the current integration value ΣIb, even if the SOC still has a sufficient margin, the normal “voltage / The current control mode ”may occur, and the switching loss reduction effect may be reduced.

  As shown in FIG. 6, in the region where the SOC is small (region A1 in FIG. 6) and the region where the SOC is large (region A3 in FIG. 6), the change in voltage with respect to the change in SOC is large. While the reliability is relatively high, in the area A2 in FIG. 6, the reliability of the SOC estimation value is relatively low. Therefore, for example, in the case of charging, in the region where the SOC is small (A1), the upper arm on-fixing mode is not determined based on the current integration value ΣIb, and the upper arm on-fixing is continued, while the estimated SOC value is a predetermined SOC reference. It is also possible to take a method of determining the end of the upper arm on fixed mode based on the current integration value ΣIb from when the value (for example, S1 in FIG. 6) or more is reached. Accordingly, priority can be given to reduction of switching loss in a region where the reliability of the SOC estimation value is relatively high, while priority is given to prevention of overcharge in a region where the reliability of the SOC estimation value is relatively low.

  FIG. 8 is a flowchart for explaining the end determination control processing for the upper arm on fixed mode in the present modification. FIG. 8 is obtained by adding S451 to the flowchart of FIG. 7 shown in the first embodiment. Note that the description of the same steps as those in FIG. 7 will not be repeated.

  Referring to FIG. 8, if the estimated SOC value is equal to or lower than the SOC upper limit value in S450 (YES in S450), ECU 30 then proceeds to S451, where the estimated SOC value is greater than the predetermined SOC reference value. It is determined whether or not it is small. Here, this predetermined SOC reference value is smaller than the SOC upper limit value, for example, as S1 in FIG. 6, and is a region where the change in voltage with respect to the change in SOC is small, that is, the region where the reliability of the estimated SOC value is low. It is preferable to set to a value that can be distinguished.

  When the estimated SOC value is smaller than the predetermined SOC reference value (YES at S451), that is, when the reliability of the estimated SOC value is relatively high and the charging power of the power storage device is in a marginal area. The ECU 30 skips the integration process of the regenerative current in S460 and S470 and the end determination process of the upper arm on fixed mode based on the current integral value ΣIb, and proceeds to the process of S480 to select the continuation of the upper arm on fixed mode. To do. Then, the upper arm switching signal UA is output to the corresponding converter so that the switching element of the upper arm of the corresponding converter is fixed on and the switching element of the lower arm is fixed off (S490).

  On the other hand, when the SOC estimated value is equal to or greater than a predetermined SOC reference value (NO in S451), that is, when the SOC estimated value is in a low reliability region or in a region where there is not much room for charging power of the power storage device, Similar to the first embodiment, the process proceeds to S460, and the end determination of the upper arm on fixed mode is performed based on the current integration value ΣIb.

  With such a configuration, overcharge (in the case of discharge) overcharge is performed in a region where the reliability of the estimated SOC value is relatively high and the charge power of the power storage device (discharge power in the case of discharge) has a margin. Therefore, priority is given to improving the switching loss by continuing the upper arm-on fixed mode, and the SOC estimation value is not reliable or the charge power (discharge power in the case of discharge) is too low. In a region where there is no allowance, it is possible to give priority to prevention of overcharge (overdischarge in the case of discharge) by determining the end of the upper arm on fixed mode based on the current integration value ΣIb.

  Note that in this description, the case where the power storage device is charged has been described, but the present invention can also be applied to the case where it is discharged, similarly to the description in Embodiment 1. That is, in S451, when the estimated SOC value is equal to or less than a predetermined SOC reference value, the process may be executed so as to determine the end of the upper arm on fixed mode based on the discharge current integrated value ΣIb.

  The region above the predetermined SOC reference value at the time of charging corresponds to the “first region” in the present invention, and the region below the predetermined SOC reference value at the time of discharging is the “second region” in the present invention. Corresponding to

[Embodiment 2]
In the second embodiment, in addition to the determination according to the first embodiment, a case where the end determination of the upper arm on fixed mode is further performed when a sudden change of the system voltage VH occurs will be described.

  When the upper arm on fixed mode is selected, it is necessary that the system voltage VH and the voltage Vb of the charging device are substantially the same, and the step-up and step-down operations by the converter are unnecessary. However, when sudden braking or rapid acceleration is performed, the required power for charging or discharging changes suddenly, so that the system voltage VH increases or decreases rapidly.

  In such a case, excessive regenerative power is input to the power storage device in a short time during charging, while excessive discharge power is output from the power storage device in a short time during discharging. Therefore, when an abrupt change in system voltage VH that cannot be absorbed by smoothing capacitor C occurs, depending on the state of SOC and the state of current integration value, the end determination of the upper arm on fixed mode is delayed, and the power storage device There is a possibility of overcharge / overdischarge.

  Therefore, in the second embodiment, when the change of the system voltage VH per predetermined time is monitored to further determine whether the upper arm on-fixed mode is finished, there is a sudden change in the charging / discharging power. The upper arm on fixed mode can be immediately terminated.

  FIG. 9 is a flowchart illustrating the end determination control process for the upper arm on fixed mode according to the second embodiment. FIG. 9 is obtained by adding S415 to the flowchart of FIG. 7 shown in the first embodiment. Note that the description of the same steps as those in FIG. 7 will not be repeated. Further, although the description will be made on the case where the power storage device is charged, it can be applied to the case of discharging as well as the description in the first embodiment. Further, the second embodiment can be similarly applied to a modification of the first embodiment.

  Referring to FIG. 9, after setting each reference value necessary for determination in S410, ECU 30 detects the amount of change per unit time of system voltage VH in S415, and the amount of change is determined to be a predetermined voltage. It is determined whether or not it is smaller than the change amount reference value (threshold value), that is, whether or not a rapid voltage fluctuation has occurred.

  Here, with respect to the change amount of the system voltage VH used for the determination, for example, the change of the moving average value for n times (n: natural number) of the control cycle is performed so as to reduce the influence of the fluctuation caused by the detection error of the voltage sensor 46. It is preferable to use an amount or the like.

  If the change amount of system voltage VH is equal to or greater than a predetermined voltage change amount reference value (NO in S415), the process proceeds to S500, the upper arm on-fixing mode is terminated, and “voltage / current control mode” Is selected. Then, ECU 30 outputs a PWM signal to the corresponding converter in S490.

  On the other hand, if the change amount of system voltage VH is smaller than the predetermined voltage change amount reference value (YES in S415), the process proceeds to S420, and the processes after S420 are performed as in the first embodiment.

  By adopting such a configuration, when the system voltage VH changes suddenly due to a sudden change in charging / discharging power, the upper arm on-fixing mode is immediately terminated to prevent the power storage device from being overcharged / overdischarged. it can.

  In the first embodiment, the modification, and the second embodiment, the power supply system including the two converters and the power storage device corresponding to each of the converters has been described. However, the power supply system including three or more converters and the power storage device is described. Is also applicable. In this case, when the upper arm on fixed mode is selected, if one power storage device corresponds to the converter that is fixed to the upper arm on, the converter and the power storage devices are connected in the same number in a one-to-one manner. Alternatively, a plurality of power storage devices may be connected to a certain converter and switched by a system relay or the like. The converter and the power storage device can also be applied to one power supply system.

  Converters 10-1 and 10-2 correspond to the “power converter” of the present invention. The ECU 30 corresponds to the “control device” of the present invention. The main positive bus MPL and the main negative bus MPL correspond to “power lines” according to the present invention. Motor generators MG1 and MG2 correspond to the “rotary electric machine” of the present invention. Further, the SOC upper limit value used in the determination in S450 at the time of charging corresponds to the “first remaining capacity reference value” of the present invention, and the SOC lower limit value used in the determination in S450 at the time of discharging is “ This corresponds to the “second remaining capacity reference value”.

  In addition, about the functional block diagram and flowchart mentioned above, it is not essential to provide all the functional blocks and steps described, and it is possible to omit some functional blocks and steps as necessary. Let me make sure.

  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 an electric vehicle according to a first embodiment. 1 is a diagram showing a configuration of a converter according to Embodiment 1. FIG. FIG. 3 is a control block diagram of an ECU according to the first embodiment. FIG. 6 is a diagram illustrating converter control in a converter control unit according to the first embodiment. 3 is a functional block diagram illustrating a configuration of converter operation mode control by a converter control unit according to Embodiment 1. FIG. It is a figure which shows the example of the relationship between the remaining capacity SOC of a electrical storage apparatus, and a terminal voltage. 6 is a flowchart for explaining an end arm control mode end determination control process in the first embodiment. It is a flowchart explaining the completion | finish determination control processing of the upper arm on fixed mode in a modification. 12 is a flowchart illustrating an end determination control process in an upper arm on fixed mode according to the second embodiment.

Explanation of symbols

  2 engine, 4 power split mechanism, 6 wheels, 10-1, 10-2 converter, 11-1, 11-2 chopper circuit, 15-1, 15-2 power storage device, 20-1, 20-2 inverter, 30 ECU, 40-1, 40-2, 46 Voltage sensor, 50-1, 50-2 Current sensor, 60-1, 60-2 Temperature sensor, 80 Power supply system, 90 Load device, 100 Electric vehicle, 110 Inverter control unit , 200 converter control unit, 210 target value setting unit, 215-1 voltage control unit, 215-2 current control unit, 220-1, 220-2 voltage / current control unit, 222-1, 222-2, 226-1 , 226-2 Subtraction unit, 224-1, 244-2 PI control unit, 228-1, 228-2 Modulation unit, 230-1, 230-2 Upper arm ON instruction unit, 235-1 235-2 Shutdown instruction unit, 240-1, 240-2 instruction selection unit, 250 determination unit, 260 mode selection unit, 270 SOC estimation unit, C, C1, C2 smoothing capacitor, CSTP upper arm on end signal, D1A, D1B, D2A, D2B diode, Ib1, Ib2 current, IR target current, L1, L2 reactor, LN1A, LN2A positive bus, LN1B, LN2B positive bus, LN1C, LN2C negative bus, MCRT1, MCRT2 motor current, MG1, MG2 motor generator, MNL Main negative bus, MPL Main positive bus, MRN1, MRN2 rotational speed, MS1, MS2 mode control signal, PL1, PL2 positive line, PR required power, Q1A, Q1B, Q2A, Q2B Power semiconductor switching element, T1, T2 temperature, TR , TR2 torque command value, Vb1, Vb2, VH voltage, VR target voltage, .theta.1, .theta.2 rotation angle.

Claims (9)

A power supply system capable of bidirectionally transferring power to and from a load device,
A plurality of power storage devices;
The power line connected to the load device is connected to each of the plurality of power storage devices, and each of them is DC power conversion bidirectionally between the corresponding power storage device of the plurality of power storage devices and the power line. A plurality of power converters for performing
A control device for controlling operations of the plurality of power conversion devices;
A current detector provided corresponding to each power storage device, for detecting a current input to and output from each power storage device;
Each of the power converters
A power semiconductor switching element inserted and connected between the corresponding power storage device and the power line;
A rectifying element connected in parallel with the power semiconductor switching element, with the direction from the power storage device toward the power line as a forward direction,
The control device includes:
The power semiconductor switching element is fixed on in one of the plurality of power conversion devices, which is started in response to establishment of a predetermined condition, and the operation of the remaining power conversion devices is stopped. A determination unit for determining the end of the predetermined operation mode;
A detection unit for detecting a current integration value obtained by integrating the current input / output to / from a power storage device corresponding to the one power conversion device with the power semiconductor switching element fixed on from the start of the predetermined operation mode; Including
The determination unit is a power supply system that ends the predetermined operation mode based on the current integration value. The control device includes:
An estimation unit that calculates an estimated value of the remaining capacity of each power storage device based on a state of each power storage device;
2. The power supply system according to claim 1, wherein the determination unit ends the predetermined operation mode based on both the current integrated value by the detection unit and the estimated remaining capacity value by the estimation unit.   The determination unit terminates the predetermined operation mode based on a comparison between the current integrated value and a predetermined reference value, and makes the reference value variable according to the remaining capacity estimated value at the start of the predetermined operation mode. The power supply system according to claim 2.   The determination unit is configured such that when the power storage device corresponding to the one power conversion device in which the power semiconductor switching element is fixed on is charged, the remaining capacity estimation value is relatively less reliable than the remaining capacity estimation value. In the case of the first region defined in advance corresponding to the remaining capacity region, the predetermined operation mode is terminated based on the current integration value, while the remaining capacity estimation value is smaller than the first region. The power supply system according to claim 2, wherein the predetermined operation mode is continued.   The determination unit is configured such that when the power storage device corresponding to the one power conversion device in which the power semiconductor switching element is fixed on is discharged, the remaining capacity estimation value is relatively reduced in reliability of the remaining capacity estimation value. When the second region is defined in advance corresponding to the remaining capacity region, the predetermined operation mode is terminated based on the current integration value, while the remaining capacity estimation value is larger than the second region. The power supply system according to claim 2, wherein the predetermined operation mode is continued.   The determination unit is configured to set the remaining capacity estimated value as a charge limit of the power storage device when charging the power storage device corresponding to the one power conversion device with the power semiconductor switching element fixed on. 5. The power supply system according to claim 2, wherein the predetermined operation mode is terminated regardless of the current integration value when the remaining capacity reference value is higher than 1.   The determination unit determines whether the remaining capacity estimation value is set as a discharge limit of the power storage device when the power storage device corresponding to the one power conversion device with the power semiconductor switching element fixed on is discharged. 6. The power supply system according to claim 2, wherein the predetermined operation mode is terminated regardless of the current integrated value when the remaining capacity reference value is lower than 2. A voltage detector for detecting a voltage of power inputted to and outputted from the load device;
The determination unit terminates the predetermined operation mode regardless of the current integration value when a change amount per predetermined time of the voltage detected by the voltage detector exceeds a predetermined voltage change amount reference value. The power supply system of any one of Claims 1-7. The load device;
An electric vehicle comprising the power supply system according to any one of claims 1 to 8,
The load device is:
A rotating electrical machine configured to generate vehicle driving force;
An electric vehicle comprising: an inverter device connected between the power line and the rotating electrical machine and configured to perform bidirectional power conversion between the power line and the rotating electrical machine.

Images