JP2009171645A - Power supply system of vehicle and its control method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power supply system of a vehicle having an enhanced failure detection probability, and to provide its control method. <P>SOLUTION: A power supply system of a vehicle includes a battery B, a voltage converter 12, a connecting unit 40, capacitors C1 and C2, a voltage sensor 21, and a controller 30 for controlling the connecting unit 40, an electric load 23 of a vehicle, and the voltage converter 12. The controller 30 controls the connecting unit 40 from an open state to a current limit connection state and controls the voltage converter 12 to a voltage non-converted state before the capacitors C1 and C2 are precharged, and then determines whether a precharge current supply passage to the capacitor C2 has failed or not based on a charging time required for the output from the voltage sensor 21 to reach a predetermined value Vtpc. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vehicle power supply device and a control method thereof, and more particularly to a vehicle power supply device including a voltage converter and a smoothing capacitor and a control method thereof.

  In recent years, hybrid vehicles that use a DC power source, an inverter, and a motor driven by the inverter as a power source have become widespread as environmentally friendly vehicles.

  Since the inverter performs on / off control of the power switching element, the current of the power supply line greatly fluctuates. Therefore, a large-capacity smoothing capacitor is provided between the DC power supply and the inverter. In addition, when the vehicle is not used, it is desirable to disconnect the high-voltage DC power supply from the inverter, so a relay is provided.

  However, if the DC power supply and the inverter are directly connected by the relay when the vehicle is started, an arc may be generated in the relay due to an excessive current (inrush current) flowing into the smoothing capacitor, and the relay may be welded. Therefore, until the smoothing capacitor is sufficiently charged, a resistor is inserted in series to limit the current and connect the DC power supply and the inverter. Such charging until the smoothing capacitor is sufficiently charged will be referred to as precharging.

  Japanese Patent Laying-Open No. 2006-246564 (Patent Document 1) discloses a failure diagnosis device and a vehicle that can accurately detect a plurality of failure modes.

This fault diagnosis device is a result of correcting the output of the current sensor using the offset value with the system main relay in the connected state after observing the offset value of the current sensor while keeping the system main relay in the disconnected state according to the start instruction In response to this, failure diagnosis of the electric circuit is performed. The offset value is observed before the precharge operation in which the capacitor is charged with the load circuit and voltage conversion circuit stopped.
JP 2006-246564 A

  One of the fault diagnoses executed in the above Japanese Patent Laid-Open No. 2006-246564 is a high-voltage disconnection fault diagnosis. In this disconnection fault diagnosis of the high voltage system, it is determined that the high voltage system wiring between the high voltage battery and the capacitor is disconnected if the current that should flow at the time of precharging the capacitor does not flow.

  However, in hybrid vehicles, to improve efficiency, the voltage of the battery, which is a DC power supply, is not increased so much, and a high voltage exceeding the counter electromotive voltage is supplied to the inverter that drives the motor at the time of high-speed rotation of the motor where the counter electromotive voltage increases. In order to achieve this, there is a type equipped with a voltage converter that boosts the voltage of the battery and supplies it to the inverter.

  In a hybrid vehicle having such a configuration, two smoothing capacitors are often provided before and after the voltage converter. Therefore, depending on the location where the disconnection occurs, even if the disconnection occurs, a current flows during capacitor precharge, so that it is difficult to detect the disconnection.

  An object of the present invention is to provide a power supply device for a vehicle with improved failure detection rate and a control method thereof.

  In summary, the present invention is a power supply device for a vehicle, comprising: a DC power supply; a voltage converter that converts a first voltage received from the DC power supply to supply a second voltage to a vehicle electrical load; A connecting portion provided between the voltage converter and capable of switching between an open state, a normal connection state, and a current limit connection state; and a first voltage for smoothing a first voltage supplied from the DC power source to the voltage converter A capacitor, a first voltage sensor for detecting a first voltage, a second capacitor for smoothing a second voltage supplied from the voltage converter to the vehicle electrical load, a connection portion, a vehicle electrical load, and a voltage And a control device for controlling the converter. The control device controls the connection unit from the open state to the current limit connection state and controls the voltage converter from the voltage non-conversion state to execute precharge processing of the first and second capacitors, and the first voltage sensor Is determined based on the charging time until the output reaches a predetermined value.

  Preferably, the vehicle power supply device further includes a second voltage sensor for detecting a second voltage supplied from the voltage converter to the vehicle electrical load. The control device executes a diagnosis process in response to the vehicle activation instruction, and when the abnormality of the second voltage sensor is detected in the diagnosis process, the completion of the precharge process is determined based on the output of the first voltage sensor. If it is determined and the second voltage sensor is diagnosed as normal in the diagnostic process, the completion of the precharge process is determined based on the output of the second voltage sensor.

  More preferably, when the second voltage sensor is diagnosed as normal and the result of the failure determination is normal, the control device switches the connection unit from the current limit connection state to the normal connection state after completion of the precharge process. At the same time, voltage conversion of the voltage converter is permitted. In addition, when the abnormality of the second voltage sensor is detected and the result of the failure determination is normal, the control device switches the connection unit from the current limit connection state to the normal connection state after the precharge processing is completed, and The voltage conversion of the converter is prohibited, and the voltage of the DC power source is directly output as the second voltage to the voltage converter.

  Preferably, the control device determines that a failure has occurred in the precharge current supply path to the second capacitor when the charging time is shorter than the predetermined time in the failure determination.

  More preferably, when it is determined that a failure has occurred in the precharge current supply path to the second capacitor, the control device controls the vehicle electrical load to the operation stop state.

  In another aspect, the present invention is a method for controlling a power supply device for a vehicle. A power supply device for a vehicle is provided between a direct current power supply, a voltage converter for converting a first voltage received from the direct current power supply to supply a second voltage to a vehicle electrical load, and the direct current power supply and the voltage converter. A connection portion capable of switching between three states of a state, a normal connection state, and a current limit connection state, a first capacitor for smoothing a first voltage supplied from a DC power source to a voltage converter, and a first voltage A first voltage sensor to detect, and a second capacitor for smoothing the second voltage supplied from the voltage converter to the vehicle electrical load. A method for controlling a power supply device for a vehicle includes a step of controlling a connection portion from an open state to a current-limited connection state and a voltage converter from a voltage non-conversion state to execute precharge processing of first and second capacitors. And a step of determining a failure of the precharge current supply path to the second capacitor based on a charging time until the output of the first voltage sensor reaches a predetermined value.

  According to the present invention, the failure detection rate is improved, and the number of cases in which a disconnection location can be specified at the time of a disconnection failure increases, so that a repair location can be determined early when a failure occurs.

  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 diagram showing a main configuration of a vehicle 100 according to an embodiment of the present invention. The vehicle 100 is a hybrid vehicle that uses a motor and an engine for driving the vehicle. However, the present invention can also be applied to an electric vehicle, a fuel cell vehicle, and the like that drive wheels with a motor.

  Referring to FIG. 1, a vehicle 100 includes a battery B, a connection unit 40, a voltage converter 12, smoothing capacitors C <b> 1 and C <b> 2, a discharge resistor R <b> 2, voltage sensors 13 and 21, and a vehicle electrical load 23. Engine 4, motor generators MG <b> 1, MG <b> 2, power split mechanism 3, wheels 2, and control device 30.

  Vehicle 100 further includes power supply lines PL1 and PL2, ground line SL, voltage sensor 10 for detecting voltage VB between terminals of battery B, and current sensor 11 for detecting current IB flowing through battery B. As the battery B, for example, a secondary battery such as a lead storage battery, a nickel metal hydride battery, or a lithium ion battery can be used.

  Connection unit 40 includes a system main relay SMRG connected between the negative electrode of battery B and ground line SL, a system main relay SMRB connected between the positive electrode of battery B and power supply line PL1, and a system main relay. It includes a resistor R1 connected in series and a system main relay SMRP connected in parallel with SMRG. System main relays SMRB, SMRG, and SMRP are controlled to be in a conductive / non-conductive state in accordance with a control signal supplied from control device 30.

  Capacitor C1 is connected between power supply line PL1 and ground line SL, and smoothes the voltage between the lines. An electric air conditioner 42 that is an electric load circuit and a DC / DC converter 44 are connected in parallel between the power supply line PL1 and the ground line SL. The DC / DC converter 44 charges the auxiliary battery 46 or supplies power to an auxiliary load (not shown).

  The voltage sensor 21 detects the voltage VL across the capacitor C1 and outputs it to the control device 30. The voltage converter 12 boosts the voltage across the capacitor C1. Capacitor C2 smoothes the voltage boosted by voltage converter 12. The voltage sensor 13 detects the inter-terminal voltage VH of the smoothing capacitor C <b> 2 and outputs it to the control device 30. The discharge resistor R2 is inserted to ensure that the voltage VH is reduced to zero after the system is stopped.

  Since the output of the voltage sensor 13 is used for motor control, the accuracy of the voltage sensor 13 is normally set higher than the accuracy of the voltage sensor 21.

  Vehicle electrical load 23 includes inverters 14 and 22. Inverter 14 converts the DC voltage supplied from voltage converter 12 into a three-phase AC and outputs the same to motor generator MG1.

  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. 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. Moreover, you may incorporate the transmission comprised so that switching of the reduction ratio of this reduction gear was possible.

  Voltage converter 12 is connected in parallel to reactor L1, one end of which is connected to power supply line PL1, IGBT elements Q1, Q2 connected in series between power supply line PL2 and ground line SL, and IGBT elements Q1, Q2. And diodes D1 and D2 connected to each other.

  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.

  Inverter 14 receives the boosted voltage from voltage converter 12 and drives motor generator MG1 to start engine 4, for example. Inverter 14 returns the electric power generated by motor generator MG 1 by the power transmitted from engine 4 to voltage converter 12. At this time, the voltage converter 12 is controlled by the control device 30 so as to operate as a step-down circuit.

  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 SL.

  U-phase arm 15 includes IGBT elements Q3 and Q4 connected in series between power supply line PL2 and ground line SL, 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 SL, 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 SL, 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.

  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 a neutral point. The other end of the U-phase coil is connected to the connection node of IGBT elements Q3 and Q4. The other end of the V-phase coil is connected to a connection node of IGBT elements Q5 and Q6. The other end of the W-phase coil is connected to a connection node of IGBT elements Q7 and Q8.

  Other power switching elements such as power MOSFETs may be used in place of the above IGBT elements Q1 to Q8.

  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 SL. Inverter 22 converts the DC voltage output from voltage converter 12 into three-phase AC and outputs the same to motor generator MG2 driving wheel 2. Inverter 22 returns the electric power generated in motor generator MG2 to voltage converter 12 in accordance with regenerative braking. At this time, the voltage converter 12 is controlled by the control device 30 so as to operate as a step-down circuit. Although the internal configuration of inverter 22 is not shown, it is similar to inverter 14, and detailed description will not be repeated.

  Control device 30 receives torque command values TR1 and TR2, motor rotation speeds MRN1 and MRN2, voltages VB and VH, current IB values, motor current values MCRT1 and MCRT2, and a start instruction IGON. Then, control device 30 outputs a signal PWC that gives an instruction including a boost instruction, a step-down instruction, an operation prohibition, and the like to voltage converter 12.

  Furthermore, control device 30 outputs signal PWM1 that gives an instruction including a drive instruction, a regeneration instruction, an operation prohibition instruction, and the like to inverter 14. The drive instruction is an instruction to convert a DC voltage that is an output of voltage converter 12 into an AC voltage for driving motor generator MG1. The regeneration instruction is an instruction for converting the AC voltage generated by the motor generator MG1 into a DC voltage and returning it to the voltage converter 12 side.

  Similarly, control device 30 outputs signal PWM <b> 2 that gives an instruction including a drive instruction, a regeneration instruction, an operation prohibition instruction, and the like to inverter 22. The drive instruction is an instruction to convert the DC voltage, which is the output of voltage converter 12, into an AC voltage for driving motor generator MG2. The regeneration instruction is an instruction for converting the AC voltage generated by the motor generator MG2 into a DC voltage and returning it to the voltage converter 12 side.

  FIG. 2 is a diagram showing a general configuration when a computer 180 is used as the control device 30.

  With reference to FIG. 2, a computer 180 includes a CPU 185, an A / D converter 181, a ROM 182, a RAM 183, and an interface unit 184.

  The A / D converter 181 converts an analog signal AIN such as an output of various sensors into a digital signal and outputs it to the CPU 185. The CPU 185 is connected to a ROM 182, a RAM 183, and an interface unit 184 via a bus 186 such as a data bus or an address bus to exchange data.

  The ROM 182 stores data such as a program executed by the CPU 185 and a map to be referred to. The RAM 183 is a work area when the CPU 185 performs data processing, for example, and temporarily stores various variables.

  The interface unit 184 communicates with other ECUs, inputs rewrite data when an electrically rewritable flash memory or the like is used as the ROM 182, or a computer such as a memory card or CD-ROM. The data signal SIG is read from a readable recording medium.

  Note that the CPU 185 transmits and receives a data input signal DIN and a data output signal DOUT from the input / output port.

  The control device 30 is not limited to such a configuration, and may be realized including a plurality of CPUs.

  FIG. 3 is a diagram for explaining a disconnection failure that enables detection and identification of an occurrence location in the present embodiment.

  Referring to FIG. 3, a point where one electrode of capacitor C1 is connected to the ground line is a first connection point, and a point where capacitor C2 is connected to the ground line is a second connection point. Assume that a break occurs in the ground line in the portion between the first and second connection points. At this time, if the voltage sensor 13 is normal, the voltage VH does not increase even when the system main relays SMRB and SMRP are turned on, so that disconnection can be detected when the capacitor C2 is precharged.

  However, there may be a case where the voltage sensor 13 fails. When a failure occurs in the voltage sensor 13, the voltage converter 12 cannot perform control for boosting. Even in this case, if the current of the battery B is supplied to the inverter as it is through the diode D1 of the voltage converter 12 without boosting, the vehicle can be driven. If the vehicle can be run in this way, the vehicle can be carried by itself to a repair shop or the like.

  When the voltage sensor 13 is evacuated at the time of failure, it is not so good that the disconnection of the ground line in the portion between the first and second connection points cannot be detected by the self-diagnosis at the start of the vehicle.

  Therefore, in the present embodiment, when the voltage sensor 13 is evacuated during failure, the voltage sensor 21 is used to detect the disconnection of the ground line shown in FIG.

  FIG. 4 is a flowchart showing a control structure of the disconnection detection process executed by the control device 30.

  Referring to FIGS. 1 and 4, first, in step S <b> 1, control device 30 determines whether or not an activation instruction by system activation signal IGON is given by a driver operating a key or button. If no activation instruction is given, the process ends. On the other hand, if it is detected in step S1 that an activation instruction has been given, then in step S2, it is determined whether there is an abnormality (VH sensor abnormality) in the voltage sensor 13 that detects the voltage VH.

  Here, the abnormality of the voltage sensor 13 means that it is determined on the control device 30 side that the detection voltage VH of the sensor cannot be used.

  For example, when the control device 30 is realized by a plurality of ECUs such as a motor generator ECU (Electric Control Unit) and a hybrid system ECU, a communication abnormality between the ECUs or a failure of the ECU that receives the sensor value may also occur. In step S2, a VH sensor abnormality is detected.

  Further, an abnormality in a power supply system for a sensor (not shown) connected to the voltage sensor 13 or an abnormality in the connection of the voltage sensor 13 itself (grounding or short circuit to the power supply) is detected as an abnormality in the VH sensor in step S2.

  If it is not determined in step S2 that the VH sensor is abnormal (NO in step S2), the process proceeds to step S10. In step S10, an internal variable is set so that the precharge determination of the capacitor C2 is performed using the VH sensor value detected by the voltage sensor 13.

  In subsequent step S11, the state of system main relays SMRB, SMRP is changed from the off state to the on state. Then, the capacitor C1 and the capacitor C2 are charged (precharge), and the VH sensor value increases. In step S12, a time is waited for the elapse of time T1 necessary for precharging.

  After time T1 has elapsed, in step S13, control device 30 determines whether or not the VH sensor value has increased based on the output of voltage sensor 13. If the VH sensor value is smaller than the abnormality detection threshold value, the process proceeds to step S8 and it is determined that the VH capacitor C2 cannot be charged. On the other hand, if the VH sensor value is equal to or greater than the abnormality detection threshold value in step S13, it is determined that the ground line disconnection shown in FIG. 3 has not occurred and the process ends.

  On the other hand, if it is determined in step S2 that the VH sensor is abnormal (YES in step S2), the process proceeds to step S3. In step S3, internal variables are set so that the precharge determination of the capacitor C2 is performed using the VL sensor value detected by the voltage sensor 21 instead of the voltage sensor 13.

  In the subsequent step S4, the state of the system main relays SMRB, SMRP is changed from the off state to the on state. Then, the capacitors C1 and C2 are charged (precharge), and the voltage VL (≈voltage VH) increases. Measurement of the time required for this precharging is started in step S5. The control device 30 monitors the increase in the voltage VL by detecting a change in the VL sensor value obtained from the output of the voltage sensor 21.

  Until the precharge time at which the measurement is started reaches the determination time T0, the process proceeds from step S6 to step S7, and it is determined whether or not the VL sensor value is larger than the threshold value Vtpc. In step S7, while the VL sensor value still does not exceed the threshold value Vtpc, the process returns to step S6, and it is determined again whether the precharge time during measurement has reached the determination time T0.

  In step S6, if the precharge time during measurement has reached the determination time T0 (NO in step S6), it has been found that a precharge time longer than the determination time is necessary. For this reason, it is determined that the precharged capacity has not decreased and the disconnection is not at the location shown in FIG. 3, and the process ends.

  The case where the VL sensor value exceeds the threshold value Vtpc in step S7 (YES in step S7) indicates that the precharge is completed before the determination time T0 is reached.

  Determination time T0 is determined according to a time constant that is the product of resistor R1 connected in series with system main relay SMRP and the total capacity of capacitors C1 and C2. Therefore, the process proceeds from step S7 to step S8 when the capacity of the precharged capacitor is smaller than the total capacity of the capacitors C1 and C2 in FIG. That is, this corresponds to a case where a disconnection occurs at a location as shown in FIG. 3 and only the capacitor C1 is precharged and the capacitor C2 is not precharged. Therefore, the process proceeds to step S8, and it is determined that the VH capacitor (capacitor C2) cannot be charged.

  After it is determined in step S8 that the VH capacitor cannot be charged, starting of the vehicle is prohibited in step S9. At this time, the inverter is shut down, and the vehicle is set in a vehicle travel impossible state (ReadyOFF state). And the process of this flowchart is complete | finished.

  FIG. 5 is an operation waveform diagram showing a case where the system startup is normally completed after the processing of steps S10 to S13 of FIG. 3 when the VH sensor is normal.

  Referring to FIGS. 1 and 5, when an activation instruction by activation signal IGON is input at time t <b> 1, a self-diagnosis of the power supply device for the vehicle is performed between times t <b> 1 to t <b> 3. If the VH sensor is diagnosed as normal at time t2 during this time (NO in step S2), the VH sensor value obtained from the output of the voltage sensor 13 is used for precharge determination.

  At time t3, system main relays SMRB and SMRP are changed from the off state to the on state. Then, the capacitors C1 and C2 are charged (precharged), and the voltage VH increases. From time t3 to t5, the control device 30 monitors the increase in the VH sensor value from which the output of the voltage sensor 13 is taken.

  At time t5 when the time T1 necessary for precharging has elapsed, the VH sensor value reaches the threshold value Vtpc, and it is determined that precharging has been completed (NO in step S13), and the precharge completion detection flag F2 and activation permission are determined. Both flags F3 are rewritten from “0” to “1”. Then, system main relay SMRG is set to an on state, system main relay SMRP is changed from an on state to an off state, system startup is completed, and a Ready ON state is set.

  After the time t5 when the ReadyON state is reached, the prohibition of the on / off switching of the IGBT in the voltage converter 12 is released, and the boosting of the voltage converter 12 is permitted.

  FIG. 6 is an operation waveform diagram showing the case where the VH sensor is abnormal, that is, after the processing of steps S3 to S6 in FIG.

  Referring to FIG. 1 and FIG. 6, when an activation instruction by activation signal IGON is input at time t1, self-diagnosis of the vehicle power supply device is executed between times t1 and t3. If a VH sensor abnormality is diagnosed at time t2 during this time (YES in step S2), the VH sensor abnormality detection flag F1 is rewritten from “0” to “1”. The VL sensor value obtained from the voltage sensor 21 instead of the output of the voltage sensor 13 is used for the precharge determination.

  At time t3, system main relays SMRB and SMRP are changed from the off state to the on state. Then, the capacitors C1 and C2 are charged (precharged), and the VL sensor value increases. At time t3 to t4, the control device 30 monitors the increase of the VL sensor value by checking the output of the voltage sensor 21.

  From time t3 to time t4 from the start of precharge until the determination time T0 elapses (YES in step S6), the VL sensor value has not yet reached the determination threshold value Vtpc. Therefore, the process proceeds from step S7 in FIG. 4 to step S6 (NO in step S7).

  When determination time T0 has elapsed (NO in step S6), it is determined that the precharged capacity has not decreased due to disconnection, and when precharge is completed at time t5, the state of system main relay SMRG changes from the off state to the on state. The system main relay SMRP is changed from the on state to the off state, the system start-up is completed, and the ReadyON state is set.

  However, since the output of the voltage sensor 13 is abnormal, the voltage converter 12 cannot be boosted. Therefore, after the time t5 when the ReadyON state is reached, the on / off switching of the IGBT in the voltage converter 12 is prohibited, and the boosting of the voltage converter 12 is prohibited. In this state, if both IGBT elements Q1, Q2 of voltage converter 12 are turned off, current is supplied to vehicle electrical load 23 side via diode D1. Further, if IGBT element Q2 is fixed in the off state and IGBT element Q1 is fixed in the on state (upper arm on state), the battery B can be charged using the power of the engine and the electric power generated by the motor generator MG1, so that the fuel As long as there remains, hybrid driving can be continued.

  Thus, according to the present embodiment, when abnormality of the VH sensor is detected at the time of starting the vehicle, it is not necessary to stop the function of the voltage converter 12, and while maintaining the running performance of the vehicle as much as possible, It is possible to move the vehicle on its own to the place to repair the failure.

  In addition, the power supply system can be restarted after being stopped once, and can be restarted even after the evacuation travel is interrupted.

  FIG. 7 is an operation waveform diagram for explaining the control when the voltage sensor 13 is abnormal and a disconnection failure has occurred, and the process proceeds from step S7 to steps S8 and S9 in FIG.

  Referring to FIG. 1 and FIG. 7, when an activation instruction by activation signal IGON is input at time t <b> 1, self-diagnosis of the vehicle power supply device is executed after time t <b> 1.

  Thereafter, when the VH sensor abnormality is diagnosed at time t2 (YES in step S2), the VH sensor abnormality detection flag F1 is rewritten from “0” to “1”. The VL sensor value obtained from the voltage sensor 21 instead of the output of the voltage sensor 13 is used for the precharge determination.

  At time t3, system main relays SMRB and SMRP are changed from the off state to the on state. Then, the capacitors C1 and C2 are charged (precharged), and the VL sensor value increases. However, since only the capacitor C1 is charged and the capacitor C2 is not charged by the disconnection of the ground line SL described with reference to FIG. 3, it rises compared to the change in the VL sensor value shown in FIG. The degree is large.

  Therefore, the VH sensor value reaches the precharge threshold value Vtpc at time t3A before the determination time T0 elapses from the start of precharge. Then, it is found that the capacitor C2 cannot be charged normally. Accordingly, at time t3A, the VH capacitor charge impossibility determination flag F4 changes from “0” to “1”.

  If there is no disconnection, as shown at time t5 in FIG. 5 or FIG. 6, the system main relay SMRB is controlled to be turned on in order to start the vehicle in the runnable state, but the disconnection of the ground line has been detected. As shown at time t5 in FIG. 7, system main relays SMRB, SMRP, and SMRG are all controlled to be in an off state, and the vehicle is set in an inoperable state (ReadyOFF state).

  Thus, according to the present embodiment, it is possible to determine the disconnection that has occurred in the ground line between the capacitors C1 and C2 even when an abnormality of the VH sensor is detected when the vehicle is started. For this reason, it is possible to prohibit the start of the vehicle when a disconnection failure occurs, and in some cases, it is also possible to leave information on the disconnection location that identifies the cause of the failure as diagnostic information.

  The above embodiment will be generally described with reference to FIG. The power supply device for a vehicle disclosed in the present embodiment includes a battery B that is a DC power supply and a voltage converter that converts the first voltage VL received from the DC power supply and supplies the second voltage VH to the vehicle electrical load. 12 is provided between the DC power source and the voltage converter 12 in an open state (SMRB, SMRP, SMRG are all off), a normal connection state (SMRB, SMRG is on, SMRP is off), and a current limit connection state (SMRB, SMRP Is switched on and SMRG is switched off), the first capacitor C1 for smoothing the first voltage VL supplied from the DC power source to the voltage converter 12, and the first voltage. A first voltage sensor 21 for detecting VL; a second capacitor C2 for smoothing the second voltage VH supplied from the voltage converter 12 to the vehicle electrical load 23; And a control unit 30 for controlling the connection unit 40, the vehicle electric load 23 and the voltage converter 12. The control device 30 controls the connection unit 40 from the open state to the current limit connection state and controls the voltage converter 12 to the voltage non-conversion state to execute the precharge processing of the first and second capacitors C1 and C2. The failure determination of the precharge current supply path to the second capacitor C2 is performed based on the charging time until the output of the first voltage sensor 21 reaches the predetermined value Vtpc.

  Preferably, the vehicle power supply device further includes a second voltage sensor 13 for detecting a second voltage VH supplied from the voltage converter 12 to the vehicle electrical load 23. The control device 30 executes a diagnostic process in response to the vehicle activation instruction IGON, and when the abnormality of the second voltage sensor 13 is detected in the diagnostic process, the completion of the precharge process is determined by the first voltage sensor 21. If the second voltage sensor 13 is diagnosed as normal in the diagnosis process, the completion of the precharge process is determined based on the output of the second voltage sensor 13.

  More preferably, as shown in FIG. 5, when the second voltage sensor 13 is diagnosed as normal and the result of the failure determination is normal, the control device 30 sets the connection unit 40 after the precharge process is completed. The voltage converter 12 is allowed to convert the voltage while switching from the current limit connection state to the normal connection state. In addition, as shown in FIG. 6, when the abnormality of the second voltage sensor is detected and the result of the failure determination is normal, the control device 30 connects the connection unit 40 to the current limiting connection after the precharge process is completed. The state is switched from the normal connection state to the normal connection state, and the voltage conversion of the voltage converter 12 is prohibited.

  Preferably, as shown in FIG. 7, control device 30 determines that a failure has occurred in the precharge current supply path to second capacitor C2 when the charging time is shorter than predetermined time T0 in the failure determination. To do.

  More preferably, as shown in FIG. 7, when controller 30 determines that a failure has occurred in the precharge current supply path to second capacitor C <b> 2, it causes vehicle electric load 23 to be in an operation stop state (ReadyOFF). ) To control.

  As shown in FIG. 4, the method for controlling the power supply device for a vehicle according to the present embodiment controls the connection unit 40 from the open state to the current limit connection state and controls the voltage converter 12 to the voltage non-conversion state. Steps (S4, S5) for performing precharge processing of the first and second capacitors C1 and C2, and the charging to the second capacitor C2 based on the charging time until the output of the first voltage sensor 21 reaches the predetermined value Vtpc And a step (S6, S7, S8) for determining a failure in the precharge current supply path.

  Note that the present invention is also applicable to electric vehicles, fuel cell vehicles, series hybrid vehicles, and the like.

  In addition, the control methods disclosed in the above embodiments can be executed by software using a computer. A program for causing a computer to execute this control method is read from a recording medium (ROM, CD-ROM, memory card, etc.) recorded in a computer-readable manner into a computer in a vehicle control device, or provided through a communication line. You may do it.

  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 diagram illustrating a main configuration of a vehicle 100 according to an embodiment of the present invention. 2 is a diagram illustrating a general configuration when a computer 180 is used as a control device 30. FIG. It is a figure for demonstrating the disconnection failure which can detect and pinpoint a generation | occurrence | production location in this Embodiment. 3 is a flowchart showing a control structure of disconnection detection processing executed by a control device 30. FIG. 4 is an operation waveform diagram showing a case where the VH sensor is normal, that is, after the processing of steps S10 to S13 in FIG. FIG. 4 is an operation waveform diagram showing a case where the VH sensor is abnormal, that is, after the processing of steps S3 to S6 in FIG. FIG. 5 is an operation waveform diagram for explaining control when the voltage sensor 13 is abnormal and a disconnection failure has occurred, and the process proceeds from step S7 to steps S8 and S9 in FIG.

Explanation of symbols

  2 wheel, 3 power split mechanism, 4 engine, 10, 13, 21 voltage sensor, 11, 24 current sensor, 12 voltage converter, 14, 22 inverter, 15 U phase arm, 16 V phase arm, 17 W phase arm, 23 Vehicle electric load, 30 control device, 40 connection unit, 42 electric air conditioner, 44 DC / DC converter, 46 auxiliary battery, 100 vehicle, 180 computer, 181 converter, 184 interface unit, 186 bus, B battery, C1, C2 Capacitor, D1-D8 diode, L1 reactor, MG1, MG2 motor generator, PL1, PL2 power line, Q1-Q8 IGBT element, R1, R2 resistor, SMRB, SMRG, SMRP System main relay.

Claims (6)

DC power supply,
A voltage converter that converts the first voltage received from the DC power source and supplies the second voltage to the vehicle electrical load; and
A connection portion provided between the DC power supply and the voltage converter and capable of switching between three states of an open state, a normal connection state, and a current limit connection state;
A first capacitor for smoothing the first voltage supplied from the DC power source to the voltage converter;
A first voltage sensor for detecting the first voltage;
A second capacitor for smoothing the second voltage supplied from the voltage converter to the vehicle electrical load;
A controller for controlling the connecting portion, the vehicle electrical load, and the voltage converter;
The control device controls the connection unit from the open state to the current limit connection state and controls the voltage converter to a voltage non-conversion state to execute precharge processing of the first and second capacitors. A vehicle power supply apparatus that performs failure determination of a precharge current supply path to the second capacitor based on a charging time during which the output of the first voltage sensor reaches a predetermined value. The power supply device of the vehicle is
A second voltage sensor for detecting the second voltage supplied from the voltage converter to the vehicle electrical load;
The control device executes a diagnostic process in response to a vehicle activation instruction, and when the abnormality of the second voltage sensor is detected in the diagnostic process, the completion of the precharge process is determined as the first voltage sensor. If the second voltage sensor is diagnosed as normal in the diagnosis process, the completion of the precharge process is determined based on the output of the second voltage sensor. The power supply device for a vehicle according to claim 1. When the second voltage sensor is diagnosed as normal and the result of the failure determination is normal, the control device connects the connection unit from the current limit connection state to the normal connection after completion of the precharge process. Switch to the state and allow voltage conversion of the voltage converter,
When the abnormality of the second voltage sensor is detected and the result of the failure determination is normal, the control device connects the connection unit from the current limit connection state to the normal connection after the precharge processing is completed. The vehicle power supply device according to claim 2, wherein the power supply device is switched to a state and voltage conversion of the voltage converter is prohibited, and the voltage converter directly outputs the voltage of the DC power supply as the second voltage.   The vehicle according to claim 1, wherein the control device determines that a failure has occurred in a precharge current supply path to the second capacitor when the charging time is shorter than a predetermined time in the failure determination. Power supply.   5. The vehicle power supply according to claim 4, wherein when the controller determines that a failure has occurred in a precharge current supply path to the second capacitor, the vehicle electric load is controlled to be in an operation stop state. 6. apparatus. A DC power supply, a voltage converter that converts the first voltage received from the DC power supply to supply a second voltage to the vehicle electrical load, an open state provided between the DC power supply and the voltage converter, A connection portion capable of switching between three states of a connection state and a current limit connection state, a first capacitor for smoothing the first voltage supplied from the DC power source to the voltage converter, and the first voltage And a second capacitor for smoothing the second voltage supplied from the voltage converter to the vehicle electrical load.
Controlling the connection portion from the open state to the current limit connection state and controlling the voltage converter to a voltage non-conversion state to perform precharge processing of the first and second capacitors;
And determining a failure in a precharge current supply path to the second capacitor based on a charging time until the output of the first voltage sensor reaches a predetermined value.

Images