JP2012223061A - Power supply system and vehicle incorporating the same and power supply system control method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately detect abnormality in a switching device installed between a power storage device and a load device in a power supply system which is used to supply electricity to the load device.SOLUTION: A power supply system comprises a power storage device 110; an SMR 115, installed in a path connecting the power storage device 110 and a load device 170, which switches electricity supply from the power storage device 110 to the load device 170 on or off; and an ECU 300. The SMR 115 includes a limiting resistor R1 and a relay SMR-P which are installed in a path connecting the power storage device 110 and the load device 170 and are connected in series. The ECU 300 estimates the temperature of the limiting resistor R1 on the basis of a voltage VB and a current IB of the power storage device, and also determines whether abnormality exists in the relay SMR-P on the basis of the estimated temperature.

Description

  The present invention relates to a power supply system, a vehicle on which the power supply system is mounted, and a control method for the power supply system, and more specifically, a technique for detecting an abnormality of a switching device that switches between power supply and load between a power supply and a load. About.

  2. Description of the Related Art In recent years, attention has been paid to a vehicle that is mounted with a power storage device (for example, a secondary battery or a capacitor) and travels by driving force generated by a motor using electric power stored in the power storage device as an environment-friendly vehicle. . Such vehicles include, for example, electric vehicles, hybrid vehicles, fuel cell vehicles, and the like.

  In such a vehicle, a switching device for switching electric power between conduction and non-conduction, such as a relay, is generally provided between the power storage device and the drive device for driving the motor. This switching device is intended to suppress wasteful loss of equipment and appropriately protect equipment by electrically insulating the power storage device and the drive device when the system is stopped or an abnormality occurs. is there. For this reason, the switching device is required to be able to be surely brought into a non-conducting state without causing contact welding of the relay or the like.

  Japanese Patent Laid-Open No. 2001-327001 (Patent Document 1) describes a smoothing capacitor connected to a drive circuit by turning off a system main relay corresponding to the switching device when an ignition signal is turned off in a hybrid vehicle. Disclosed is an abnormality diagnosis device that determines that the system main relay is welded when the voltage does not converge to zero.

JP 2001-327001 A JP 2008-178286 A

  According to the technique described in Japanese Patent Laid-Open No. 2001-327001 (Patent Document 1), in the system main relay, an abnormality occurs when both of the relays connected to the positive electrode terminal and the negative electrode terminal of the power storage device are welded. However, when only one of the relays is welded, an abnormality cannot be determined.

  Further, in such a switching device, when power supply is started, that is, when the relay is turned on, a separate resistor connected in series is used to prevent a large inrush current from flowing through the drive device and the capacitor. There is a configuration in which this relay is connected in parallel to at least one of the positive electrode side and the negative electrode side relay. In such a configuration, when it is determined that there is welding using the technique described in Japanese Patent Laid-Open No. 2001-327001 (Patent Document 1), which of the relays configured in parallel is welded. Cannot be judged.

  The present invention has been made to solve such problems, and an object thereof is to provide a switching system provided between a power storage device and a load device in a power supply system for supplying power to the load device. Appropriate detection of device abnormalities.

  A power supply system according to the present invention includes a power supply device, a switching device, and a control device for determining an abnormality of the switching device, and supplies power to a load. The switching device is provided in a path connecting the power supply device and the load, and switches between supply and interruption of power from the power supply device to the load. The switching device is provided in a path connecting the load and the power supply device, and includes a resistor and a first switch connected in series. The control device determines abnormality of the first switch based on the temperature of the resistor.

  Preferably, the switching device further includes a second switch connected in parallel to the resistor and the first switch connected in series. In the control device, the temperature of the resistor in the state where the shut-off command for both the first and second switches is output, the shut-off command for the first switch is output, and the turn-on command for the second switch is When the temperature of the resistor in the output state is higher than that of the resistor, it is determined that an abnormality has occurred in which the first switch is fixed to the conductive state.

  Preferably, when the temperature of the resistor exceeds the threshold value, the control device prohibits the switching device from operating until a predetermined time period elapses from when the switching device was last operated.

  Preferably, when the voltage applied to the load does not decrease after the shut-off command for both the first and second switches is output, the control device performs conduction in at least one of the first and second switches. It is determined that an abnormality fixed to the state has occurred.

  Preferably, after the shut-off command for both the first and second switches is output, the control device is configured such that the voltage applied to the load does not decrease and the temperature of the resistor does not increase. It is determined that an abnormality has occurred in which the switch 2 is fixed in the conductive state.

  Preferably, the control device prohibits the switching device from operating when an abnormality has occurred in the second switch.

  Preferably, the switching device further includes a third switch provided in a route different from the route in which the first and second switches are provided, out of the two routes connecting the load and the power supply device. When the control device shifts from the state in which the conduction command of both the second and third switches is output to the state in which the cutoff command of the second switch is output, the control device Judge abnormalities.

  Preferably, the control device calculates the temperature of the resistor based on the voltage of the power supply device and the current input to and output from the power supply device.

  The power supply system control method according to the present invention is a control method for a power supply system for supplying power from a power supply device to a load. The power supply system includes a switching device that is provided in a path connecting the power supply device and the load and that switches between supply and interruption of power from the power supply device to the load. The switching device includes a resistor and a first switch connected in series provided in a path connecting the load and the power supply device. The control method includes a step of detecting a temperature of the resistor, and a step of determining an abnormality of the first switch based on the detected temperature of the resistor.

  The vehicle according to the present invention is a vehicle that can travel using the driving force generated by the electric power from the power supply device, the driving device for generating the driving force, the switching device, and the abnormality of the switching device. And a control device for determination. The switching device is provided in a path connecting the power supply device to the drive device, and switches between supply and interruption of power from the power supply device to the drive device. The switching device is provided in a path connecting the driving device and the power supply device, and includes a resistor and a first switch connected in series. The control device determines abnormality of the first switch based on the temperature of the resistor.

  In the present invention, in the power supply system for supplying power to the load device, it is possible to appropriately detect an abnormality of the switching device provided between the power storage device and the load device.

1 is an overall block diagram of a vehicle equipped with a power supply system according to the present embodiment. It is a figure which shows the relationship between the operating state of each relay of SMR, and the voltage VL at the time of the start of ignition signal, and completion | finish. In this Embodiment, it is a functional block diagram for demonstrating the control performed by ECU. In the present embodiment, it is a flowchart showing the details of the SMR operation restriction control process based on the temperature of the limiting resistance executed by the ECU at the start of power supply from the power storage device to the PCU. It is a figure which shows an example of the relationship between the temperature of a resistor, and resistance value at the time of using a semiconductor as a limiting resistance. It is a figure which shows an example of the relationship between the temperature of a resistor, and resistance value at the time of using a metal as a limiting resistance. 5 is a flowchart for illustrating details of an SMR abnormality determination control process executed by an ECU in the present embodiment. It is a figure for demonstrating the method of judging which of the relay of a parallel structure is welding.

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

FIG. 1 is an overall block diagram of a vehicle equipped with a power supply system according to the present embodiment.
Referring to FIG. 1, vehicle 100 includes a power supply system 105 and a load device 170.

  The power supply system 105 includes a power storage device 110 as a power supply device, a voltage sensor 111, a current sensor 112, a system main relay (SMR) 115 as a switching device, and an ECU (Electronic Control Unit) as a control device. ) 300.

  Load device 170 includes a PCU (Power Control Unit) 120 that is a drive device, motor generators 130 and 135, a power transmission gear 140, drive wheels 150, and an engine 160 that is an internal combustion engine. PCU 120 includes a converter 121, inverters 122 and 123, voltage sensors 124 and 125, and capacitors C1 and C2.

  The power storage device 110 is a power storage element configured to be chargeable / dischargeable. The power storage device 110 includes, for example, a secondary battery such as a lithium ion battery, a nickel metal hydride battery, or a lead storage battery, or a power storage element such as an electric double layer capacitor.

  Power storage device 110 is connected to PCU 120 via power line PL1 and ground line NL1. Then, power storage device 110 supplies power for generating driving force of vehicle 100 to PCU 120. Power storage device 110 stores the electric power generated by motor generators 130 and 135. The output of power storage device 110 is, for example, about 200V.

  Voltage sensor 111 detects voltage VB of power storage device 110 and outputs the detection result to ECU 300. Current sensor 112 detects current IB input to and output from the power storage device, and outputs the detected value to ECU 300.

  SMR 115 includes relays SMR-B, SMR-P, SMR-G, and a limiting resistor R1. Relay SMR-B is connected to a positive electrode terminal of power storage device 110 and power line PL1. Relay SMR-G is connected to the negative electrode terminal of power storage device 110 and ground line NL1. A configuration in which the relay SMR-P and the limiting resistor R1 are connected in series is connected in parallel to the relay SMR-G.

  Each relay included in SMR 115 can be individually operated based on control signal SE1 from ECU 300, and switches between supply and interruption of power between power storage device 110 and PCU 120.

  The limiting resistor R1 is a current limiting resistor for preventing a large inrush current from flowing to the PCU 120 when power supply from the power storage device to the PCU 120 is started. The operation of each relay included in the SMR 115 will be described later with reference to FIG.

  In the present embodiment, SMR 115 will be described as an example of a relay configured to be able to close and open contacts. However, SMR 115 is, for example, power that can be switched between conduction and non-conduction. Switching element may be used. That is, each relay of the SMR 115 is an example of the “switch” in the present invention.

  Converter 121 performs voltage conversion between power line PL1 and ground line NL1, power line PL2 and ground line NL1, based on control signal PWC from ECU 300.

  Inverters 122 and 123 are connected in parallel to power line PL2 and ground line NL1. Inverters 122 and 123 convert DC power supplied from converter 121 to AC power based on control signals PWI1 and PWI2 from ECU 300, respectively, and drive motor generators 130 and 135, respectively.

  Capacitor C1 is provided between power line PL1 and ground line NL1, and reduces voltage fluctuation between power line PL1 and ground line NL1. Capacitor C2 is provided between power line PL2 and ground line NL1, and reduces voltage fluctuation between power line PL2 and ground line NL1.

  Voltage sensors 124 and 125 detect voltages VL and VH applied to both ends of capacitors C1 and C2, respectively, and output the detected values to ECU 300.

  Motor generators 130 and 135 are AC rotating electric machines, for example, permanent magnet type synchronous motors having a rotor in which permanent magnets are embedded.

  The output torque of motor generators 130 and 135 is transmitted to drive wheels 150 via power transmission gear 140 including a reduction gear and a power split mechanism, and causes vehicle 100 to travel. Motor generators 130 and 135 can generate electric power by the rotational force of drive wheels 150 during regenerative braking operation of vehicle 100. Then, the generated power is converted into charging power for power storage device 110 by PCU 120.

  Motor generators 130 and 135 are also coupled to engine 160 through power transmission gear 140. Then, ECU 300 causes motor generators 130 and 135 and engine 160 to operate in a coordinated manner to generate a necessary vehicle driving force. Further, motor generators 130 and 135 can generate electric power by rotation of engine 160, and can charge power storage device 110 using the generated electric power. In the present embodiment, motor generator 135 is used exclusively as an electric motor for driving drive wheels 150, and motor generator 130 is used exclusively as a generator driven by engine 160.

  In FIG. 1, a configuration in which two motor generators are provided is shown as an example. However, the number of motor generators is not limited to this, and the number of motor generators is one, or more than two motor generators are provided. It is good also as a structure. The engine 160 is not an essential component, and may be an electric vehicle or a fuel cell vehicle that does not include the engine 160. Furthermore, the load connected to power storage device 110 is not limited to the vehicle as described above, and the present embodiment can be applied to any electrical device that is driven by electric power output from power storage device 110.

  Although not shown in FIG. 1, ECU 300 includes a CPU (Central Processing Unit), a storage device, and an input / output buffer. The ECU 300 inputs signals from sensors and outputs control signals to devices, and stores power. The device 110 and each device of the vehicle 100 are controlled. Note that these controls are not limited to processing by software, and can be processed by dedicated hardware (electronic circuit).

  ECU 300 calculates a state of charge (SOC) of power storage device 110 based on detected values of voltage VB and current IB from voltage sensor 111 and current sensor 112 provided in power storage device 110.

  ECU 300 generates and outputs a control signal for controlling PCU 120, SMR 115, and the like. In FIG. 1, one control device is provided as the ECU 300. However, for example, a control device for the PCU 120, a control device for the power storage device 110, or the like is provided individually for each function or for each control target device. It is good also as a structure which provides a control apparatus.

  FIG. 2 is a diagram showing the relationship between the normal operating state of each relay of the SMR 115 and the voltage VL of the capacitor C1 when the ignition signal IG starts and ends. In FIG. 2, the horizontal axis represents time, and the vertical axis represents the state of the ignition signal IG, the voltage VL of the capacitor C1, and the operating states of the relays SMR-B, SMR-G, and SMR-P of the SMR 115.

  Referring to FIGS. 1 and 2, when ignition signal IG is turned on at time t1, first, relay SMR-B and relay SMR-P are closed while relay SMR-G is open. . Thereby, electric power from power storage device 110 is supplied to load device 170, capacitor C1 is precharged, and voltage VL gradually increases. At this time, since the current flows through the limiting resistor R1, an excessive inrush current to the capacitor C1 and the converter 121 is suppressed, and the increase in the voltage VL at the time of precharging becomes moderate.

  Then, at the time t2 after the precharge of the capacitor C1 is completed and the voltage VL reaches the voltage divided by the limiting resistor R1, the relay SMR-G is closed, and accordingly the relay SMR-P Is released. Thereby, power consumption by limiting resistor R1 is eliminated, voltage VL rises to a voltage substantially equal to voltage VB of power storage device 110, and then traveling control is started.

  At time t3, when the ignition signal IG is turned off by the user for the end of traveling, the relays SMR-B and SMR-G are opened. Thereby, the electric power from power storage device 110 to load device 170 is cut off.

  As described above, in the SMR 115 that switches between supply and interruption of power from the power storage device 110 to the load device 170, if the contact is opened in a state where the temperature of the relay is excessively high, the contact is fused to the contact Abnormalities such as this may occur. In the relay SMR-P provided with the limiting resistor R1 for suppressing the inrush current, the temperature of the relay SMR-P tends to increase due to the heat generated by the limiting resistor R1 when the capacitor C1 is precharged. It is in.

  In particular, when connection and disconnection of the SMR 115 are repeated in a short time, the capacitor C1 is precharged again before the temperature of the limiting resistor R1 and the relay SMR-P is sufficiently lowered. The temperature of the SMR-P is more likely to rise, increasing the possibility of failure.

  Therefore, when designing, the relay SMR-P may be designed to have a temperature margin more than that of the relays SMR-B and SMR-G, resulting in a larger part size and higher cost. It is said.

  In addition, in order to suppress the excessive temperature rise as described above, the relay temperature is estimated from the number of SMR 115 connection / disconnection operations in a predetermined time, and when the number of operations exceeds a predetermined number of times, A technique for prohibiting the operation of the relay may be employed to prevent damage. However, the temperature estimated from the number of operations does not include factors such as the outside air temperature, so the accuracy is not so high, and the operation may be prohibited even if the relay is actually operable. . In such a case, not only will it be excessive protection and an unnecessary failure will be caused, but there is also a possibility that useless loss may be caused by maintaining the state where the SMR 115 is connected. In addition, it may be necessary to change the limit value of the number of operations corresponding to the environment of the ship destination of the vehicle.

  Further, in a switching device having a configuration such as SMR 115, the welding confirmation for relay SMR-G may be determined by the voltage VL of capacitor C1 after relay disconnection. In such a method, there is a possibility that welding has occurred in the relay SMR-P connected in parallel to the relay SMR-G, but it cannot be determined which relay has welding. . If welding occurs only in the relay SMR-P, this is not a preferable state. However, since the inrush current can be suppressed by the limiting resistor R1 when the SMR 115 is connected, it is not necessary to immediately prohibit the operation of the SMR 115. However, in the above-described method, it is impossible to determine which relay is welded. Therefore, the reconnection of the SMR 115 is prohibited on the safe side, and as a result, there is a possibility that the relay will be stuck on the road.

  Therefore, in the present embodiment, welding is performed on either of the relays SMR-G and SMR-P based on the temperature of the limiting resistor R1 connected in series with the relay SMR-P used when the capacitor C1 is precharged. If only the relay SMR-P is welded, it is possible to travel to a place where the vehicle can be repaired without unnecessarily prohibiting the operation of the SMR. Possible to perform abnormality detection control.

  FIG. 3 is a functional block diagram for illustrating control executed by ECU 300 in the present embodiment. Each functional block described in the functional block diagram of FIG. 3 is realized by hardware or software processing by ECU 300.

  Referring to FIGS. 1 and 3, ECU 300 includes a temperature detection unit 310, a determination unit 320, and a drive control unit 330.

  Temperature detection unit 310 receives voltage VB and current IB of power storage device 110 from voltage sensor 111 and current sensor 112, respectively. The temperature detector 310 calculates the resistance value of the limiting resistor R1 from the voltage VB and the current IB, and calculates the temperature Tres of the limiting resistor R1 using a map indicating the relationship between the resistance value and the temperature of the limiting resistor R1. To do. Then, the temperature detection unit 310 outputs the calculated temperature Tres to the determination unit 320.

  Determination unit 320 receives temperature Tres from temperature detection unit 310, control signal SE1 for operating SMR 115, voltage VL from voltage sensor 124, and ignition signal IG. When the determination unit 320 starts supplying power from the power storage device 110 to the PCU 120, the temperature of the limiting resistor R1 when the relays SMR-B and SMR-P are closed and the relay SMR-G is opened. Whether Tres is permitted to operate SMR 115 is determined based on whether Tres is within a predetermined allowable temperature or not. This is to prevent the relays of the SMR 115 from being damaged due to high temperatures when the vehicle 100 is frequently started and stopped.

  When the temperature Tres exceeds a predetermined allowable temperature, the determination unit 320 sets an inhibition signal INH for inhibiting the operation of the SMR 115 to ON and outputs the inhibition signal INH to the drive control unit 330. On the other hand, when the temperature Tres is equal to or lower than a predetermined allowable temperature, and when a predetermined time has elapsed after the prohibition signal INH is turned on, the determination unit 320 sets the prohibition signal INH to off and sets the drive control unit To 330.

  In addition, when the ignition signal IG is turned off and the traveling control of the vehicle 100 is finished, the determination unit 320 outputs a control signal SE1 that opens the relay SMR-G while keeping the relay SMR-B closed. Whether or not the relays SMR-P and SMR-B are welded is determined on the basis of whether or not the voltage VL is reduced. When it is determined that welding has occurred, the relays SMR-P, SMR- are determined based on whether or not the temperature Tres of the limiting resistor R1 has increased compared to before the relay SMR-G is opened. It is further determined which of B is welded. Determination unit 320 outputs determination signal FLR indicating the presence or absence of welding to drive control unit 330.

  Drive control unit 330 receives prohibition signal INH and determination signal FLR from determination unit 320, and ignition signal IG. Drive control unit 330 generates control signals SE1, PWC, PWI1, and PWI2 in response to the state of ignition signal IG, and controls SMR 115 and converter 121 and inverters 122 and 123 in PCU 120. At this time, the operation of SMR 115 is limited by inhibition signal INH and determination signal FLR from determination unit 320.

  FIG. 4 is a flowchart showing details of the operation restriction control process of SMR 115 based on the temperature of restriction resistor R1 executed by ECU 300 when power supply from power storage device 110 to PCU 120 is started in the present embodiment. In the flowchart shown in FIG. 4 and FIG. 7 described later, the process is realized by a program stored in advance in ECU 300 being called from the main routine and executed in a predetermined cycle. Alternatively, for some steps, processing can be realized by dedicated hardware (electronic circuit).

  Referring to FIGS. 1 and 4, ECU 300 determines in step (hereinafter step is abbreviated as S) 200 whether ignition signal IG has transitioned from off to on.

  If ignition signal IG has not transitioned from OFF to ON (NO in S200), ECU 300 returns the process to the main routine.

  When ignition signal IG transitions from OFF to ON (YES in S200), the process proceeds to S210, and ECU 300 maintains relays SMR-G OFF (opened) and relays SMR-B, SMR- A command to turn P on (close) is output.

  In that state, ECU 300 obtains voltage VB and current IB of power storage device 110 (S220), and calculates resistance value R of limiting resistance R1 by R = VB / IB (S230).

  Thereafter, in S240, ECU 300 calculates temperature Tres of limiting resistor R1 from a map showing the relationship between resistance value R and temperature Tres, which is determined by the characteristics of limiting resistor R1, as shown in FIGS. FIG. 5 is an example of a map when a semiconductor is used as the limiting resistor R1, and in this case, the resistance value R and the temperature Tres are in an inversely proportional relationship. FIG. 6 is an example of a map in the case where a metal is used as the limiting resistor R1, and in this case, the resistance value R and the temperature Tres have a substantially proportional relationship. Strictly speaking, the resistance value R indicates a resistance value of the limiting resistor R1 and a combined resistance value such as a discharge resistor connected in parallel to the capacitor C1, for example, as described above. Since R is used when indirectly estimating the temperature of the limiting resistor R1, it can be used as a parameter indicating the resistance value of the limiting resistor R1.

  Referring to FIG. 4 again, ECU 300 next determines in S250 whether or not the calculated temperature Tres of limiting resistor R1 is equal to or less than a predetermined allowable value α.

  If temperature Tres is equal to or lower than a predetermined allowable value α (YES in S250), ECU 300 determines that SMR 115 has not reached a temperature that would cause damage. Then, in S260, ECU 300 sets prohibition signal INH to off and permits operation of SMR 115.

  On the other hand, when temperature Tres is greater than predetermined allowable value α (NO in S250), ECU 300 determines that there is a high possibility that SMR 115 has reached a temperature that would cause damage. Then, the process proceeds to S270, and ECU 300 sets inhibition signal INH to on so that the operation of SMR 115 is not executed. As a result, the frequent on / off operation of the SMR 115 is limited, so that the temperature of the SMR 115 is further prevented from rising.

  Then, in S280, ECU 300 determines whether or not a predetermined time has passed after the prohibition signal INH is turned on. Since the state of the SMR 115 is maintained, as described with reference to FIG. 2, when the precharge of the capacitor C1 is completed in the state where the load device 170 is not driven, a current substantially flows through the SMR 115 and the limiting resistor R1. Absent. Therefore, the temperature of the SMR 115 can decrease with time. Therefore, the predetermined time is determined based on the time during which the temperature of the SMR 115 can sufficiently decrease.

  If the predetermined time has not elapsed (NO in S280), since the temperature of SMR 115 has not yet decreased, the process returns to S280, and ECU 300 waits for the predetermined time to elapse.

  If the predetermined time has elapsed (YES in S280), ECU 300 determines that the temperature of SMR 115 has sufficiently decreased. Then, ECU 300 advances the process to S260, sets inhibition signal INH to OFF, and permits the operation of SMR 115.

  Next, the abnormality determination control of the relays SMR-P and SMR-G at the end of traveling will be described with reference to FIG.

  Referring to FIGS. 1 and 7, ECU 300 determines in S100 whether ignition signal IG has shifted from on to off.

  If ignition signal IG has not shifted from on to off (NO in S100), ECU 300 returns the process to the main routine without performing the abnormality determination control, since it does not apply at the end of travel.

  When ignition signal IG shifts from on to off (YES in S100), the process proceeds to S110, and ECU 300 outputs a disconnection command for relay SMR-G.

  Next, in S120, ECU 300 obtains voltage VL applied to capacitor C1 from voltage sensor 124. As described with reference to FIG. 2, in the normal state of SMR 115, when ignition signal IG is turned on and normal traveling is performed, relay SMR-B and relay SMR-G are closed, and relay SMR- P is in an open state. Therefore, when the relay SMR-G by S110 is appropriately opened by the cutoff command, the circuit configured by the power storage device 110 and the load device 170 becomes an open circuit, and power from the power storage device 110 is supplied to the load device 170. Disappear. Therefore, the electric power stored in the capacitor C1 should be gradually consumed by a high-resistance discharge resistor (not shown) connected in parallel to the capacitor C1, thereby gradually reducing the voltage VL.

  In S130, ECU 300 determines whether or not relay SMR-G may be welded based on whether or not voltage VL has decreased.

  If there is no possibility that relay SMR-G is welded (NO in S130), that is, if a decrease in voltage VL is detected, relays SMR-G and SMR-P are both open, so relay SMR Neither -G nor SMR-P is welded. Therefore, ECU 300 skips the subsequent processing and returns the processing to the main routine.

  If relay SMR-G may be welded (YES in S130), that is, if a decrease in voltage VL is not detected, ECU 300 advances the process to S140.

  At this time, the relay SMR-G may be welded, or the relay SMR-P may be welded even though the relay SMR-G is normally opened.

  Therefore, in order to determine which welding of relay SMR-G and relay SMR-P has occurred, ECU 300 performs relay in S140 by the same processing as the processing described in S220 to S240 in the flowchart of FIG. The temperature of the limiting resistor R1 connected in series with the SMR-P is detected.

  In S150, ECU 300 determines whether or not detected temperature Tres of limiting resistor R1 is increasing. When welding has occurred in relay SMR-G, even if welding has occurred in relay SMR-P, the current supplied to capacitor C1 flows through relay SMR-G having a small resistance value. That is, since no current flows through the relay SMR-P, the temperature Tres of the limiting resistor R1 is almost unchanged as shown by the curve W10 in FIG.

  On the other hand, when welding occurs only in the relay SMR-P, the current supplied to the capacitor C1 flows through the relay SMR-P and the limiting resistor R1. Therefore, the temperature Tres of the limiting resistor R1 rises to a temperature at which heat generation and heat dissipation due to current are in an equilibrium state, as indicated by a curve W11 in FIG.

  Therefore, when temperature Tres of limiting resistance R1 is increasing (YES in S150), ECU 300 advances the process to S160 and determines that welding has occurred in relay SMR-P.

  On the other hand, when temperature Tres of limiting resistance R1 has not risen (NO in S150), ECU 300 proceeds to S170 and determines that at least relay SMR-G is welded. In this case, when the ignition signal IG is turned on when the user tries to resume running, no current flows through the limiting resistor R1, so that a large inrush current is applied to the load device 170, causing a malfunction of the device. Since there is a risk of damage, ECU 300 prohibits restarting of SMR 115 in S180.

  By performing control according to the above-described processing, it is possible to appropriately detect the temperature rise of relay SMR-P and to appropriately determine abnormality of SMR based on the temperature. In addition, since the abnormality of the relays SNR-G and SMR-P can be determined separately, it is possible to prevent the SMR operation from being unnecessarily restricted.

  Although not shown in FIG. 7, when it is determined that welding has occurred in the relays SMR-G and SMR-P, a warning device or the like (not shown) is used to notify the user of the occurrence of an abnormality. You may make it do.

  Further, the temperature Tres of the limiting resistor R1 can be set to a temperature from a temperature sensor (not shown) for detecting the temperature of the limiting resistor R1 in the vicinity of the limiting resistor R1. . Alternatively, the temperature can be estimated by detecting the current flowing through the limiting resistor R1. However, it is preferable to calculate from the resistance value calculated from the voltage VB and current IB of the power storage device 110 as in the above example, since it is not necessary to add new equipment and increase in the number of parts can be suppressed.

  In the above-described embodiment, in SMR 115, the configuration in which relay SMR-P in which limiting resistor R <b> 1 is connected in series is connected in parallel to relay SMR-G on the negative electrode side path of power storage device 110 has been described. The relay SMR-P to which the limiting resistor R1 is connected in series may be connected in parallel to the relay SMR-B on the path on the positive electrode side of the power storage device 110. In this case, when the SMR 115 is connected, the relays SMR-P and SMR-G are closed during precharging, and the relay SMR-B is closed and the relay SMR-P is opened after the precharging is completed. Further, when SMR 115 is shut off, welding confirmation in relays SMR-B and SMR-P is executed.

  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.

  100 vehicle, 105 power supply system, 110 power storage device, 111, 124, 125 voltage sensor, 112 current sensor, 115 SMR, 120 PCU, 121 converter, 122, 123 inverter, 130, 135 motor generator, 140 power transmission gear, 150 drive Wheel, 160 engine, 170 load device, 300 ECU, 310 temperature detection unit, 320 determination unit, 330 drive control unit, C1, C2 capacitor, NL1 ground line, PL1, PL2 power line, R1 limiting resistor, SMR-B, SMR- G, SMR-P relay.

Claims (10)

A power supply system for supplying power to a load,
A power supply;
Provided in a path connecting the power supply device and the load, and a switching device for switching between supply and interruption of power from the power supply device to the load;
A control device for determining an abnormality of the switching device,
The switching device is provided in a path connecting the load and the power supply device, and includes a resistor and a first switch connected in series,
The control device is a power supply system that determines an abnormality of the first switch based on a temperature of the resistor. The switching device further includes a second switch connected in parallel to the resistor and the first switch connected in series,
In the control device, the temperature of the resistor in a state in which a shutoff command for both the first and second switches is output, the shutoff command for the first switch is output, and the second switch 2. The power supply according to claim 1, wherein when the temperature of the resistor is higher than a state in which a switch conduction command is being output, it is determined that an abnormality has occurred in which the first switch is fixed to a conduction state. system.   When the temperature of the resistor exceeds a threshold value, the control device prohibits the switching device from operating until a predetermined time period elapses from when the switching device was last operated. The power supply system according to claim 2.   In the case where the voltage applied to the load does not decrease after the cutoff command for both the first and second switches is output, the control device, in at least one of the first and second switches, The power supply system according to claim 2 or 3, wherein it is determined that an abnormality that is fixed in a conductive state has occurred.   In the case where the voltage applied to the load does not decrease and the temperature of the resistor does not increase after the cutoff command of both the first and second switches is output, The power supply system according to claim 4, wherein an abnormality that causes the second switch to be fixed in a conductive state is determined.   The power supply system according to claim 5, wherein the control device prohibits the switching device from operating when an abnormality occurs in the second switch. The switching device further includes a third switch provided in a route different from a route in which the first and second switches are provided among two routes connecting the load and the power supply device,
When the control device shifts from a state in which a conduction command for both the second and third switches is output to a state in which a cutoff command for the second switch is output, the first and second switches The power supply system of any one of Claims 2-6 which determines abnormality of 2 switches.   The power supply system according to claim 1, wherein the control device calculates a temperature of the resistor based on a voltage of the power supply device and a current input / output to / from the power supply device. A control method of a power supply system for supplying power to a load from a power supply device,
The power supply system is provided in a path connecting the power supply device and the load, and includes a switching device for switching between supply and interruption of power from the power supply device to the load,
The switching device includes a resistor and a first switch connected in series provided in a path connecting the load and the power supply device,
The control method is:
Detecting the temperature of the resistor;
And determining the abnormality of the first switch based on the detected temperature of the resistor. A vehicle capable of traveling using driving force generated by power from a power supply device,
A driving device for generating the driving force;
A switching device provided in a path connecting the power supply device to the drive device, and for switching between supply and interruption of power from the power supply device to the drive device;
A control device for determining an abnormality of the switching device,
The switching device is provided in a path connecting the driving device and the power supply device, and includes a resistor and a first switch connected in series,
The control device determines whether the first switch is abnormal based on a temperature of the resistor.

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