JP2017041928A - Power system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power system which supplies power, of which voltage is converted, again to a load, even in a case of the output of a common abnormal signal in between a case when a short-circuit fault occurs in a switching element and a case when an abnormality different from the short-circuit fault occurs.SOLUTION: A drive IC outputs a failure signal to an ECU when detecting the abnormality of a switching element. Meanwhile, the ECU, on receiving a failure signal from the drive IC when a fuse is in a connection state, performs confirmation processing which outputs a gate signal to the switching element in which the abnormality is detected, after switching over the fuse from the connection state to a cutoff state. When the failure signal is not received again from the drive IC during the confirmation processing, the ECU identifies that the detected abnormality is a short-circuit fault, so as to switch over the fuse from the cutoff state to the connection state.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a power supply system, and more particularly to a power supply system that supplies power to a load.

  In electric vehicles such as electric vehicles and hybrid vehicles, a power supply system that supplies electric power to a load such as a motor is mounted.

  For example, Japanese Unexamined Patent Application Publication No. 2014-54102 (Patent Document 1) discloses an electric vehicle in which a boost converter is provided between a motor and a battery. In this electric vehicle, when it is detected that a short circuit failure has occurred in the switching element of the boost converter, the switching element is disconnected from the battery by the circuit breaker.

JP 2014-54102 A

  Some drive modules for driving a switching element are configured to output an abnormal signal when an abnormality occurs in the switching element. If it is possible to specify that an abnormality that has occurred in the switching element is a short-circuit failure using this abnormality signal, it is possible to determine whether or not to activate the circuit breaker.

  However, if the drive module is configured to output a common abnormality signal when a short circuit failure occurs and when an abnormality different from the short circuit failure occurs, an abnormality signal is output. Even if it is detected, it cannot be specified that the detected abnormality is a short-circuit fault. For this reason, the electric power voltage-converted by the boost converter cannot be supplied again to a load such as a motor. That is, even if the detected abnormality is different from the short-circuit fault, the possibility that the short-circuit fault has occurred cannot be ruled out, and the switching element cannot be connected to the battery by the circuit breaker. It will remain disconnected from the battery.

  The present invention has been made in order to solve the above-described problem, and its purpose is common to a case where a short-circuit fault has occurred in the switching element and a case where an abnormality different from the short-circuit fault has occurred. Even when the abnormal signal is output, the voltage-converted power can be supplied to the load again.

  The power supply system according to the present invention supplies power to a load. The power supply system includes a power storage device, a voltage conversion device, a switching device, a control device, and an abnormal signal output device. The power storage device can supply power to a power supply line to the load. The voltage conversion device includes an upper switching element provided between the positive electrode of the power storage device and the power supply line, and a lower switching provided between a path connecting the positive electrode and the upper switching element of the power storage device and the negative electrode of the power storage device. Element. The switchgear can be switched between a cut-off state in which at least one of the upper switching element and the lower switching element is disconnected from the power storage device, and a connection state in which at least one switching element is connected to the power storage device. Composed. The control device controls the upper switching element, the lower switching element, and the switchgear. The abnormality signal output device outputs an abnormality signal to the control device when an abnormality of at least one of the switching elements is detected. When the control device receives an abnormal signal from the abnormal signal output device, the control device outputs an ON signal for closing the switching element to at least one switching element in which the abnormality is detected after switching the switching device from the connected state to the disconnected state. When the abnormality signal is not received again from the abnormality signal output device, the abnormality is identified as an abnormality different from the short-circuit failure, and the switchgear is switched from the shut-off state to the connected state.

  According to such a configuration, when an abnormality of at least one of the upper switching element and the lower switching element is detected, an abnormal signal is output from the abnormal signal output device to the control device. On the other hand, when the control device receives an abnormal signal from the abnormal signal output device, the control device switches an on / off device from the connected state to the cut-off state, and then sends an on signal to close the switching device to at least one switching device in which the abnormality is detected. If the abnormality signal is not received again from the abnormality signal output device, the detected abnormality is identified as an abnormality different from the short-circuit failure, and the switchgear is switched from the cutoff state to the connected state. As a result, even if a common fault signal is output when a short-circuit fault occurs in the switching element and when a fault different from the short-circuit fault occurs, the detected fault is short-circuit fault. When the abnormality is different from the above, the power converted by the voltage converter can be supplied to the load again.

It is a figure which shows the structure of an electric vehicle. It is a figure which shows the structure of a drive module. It is a figure for demonstrating the output pattern of a fail signal. It is a flowchart which shows an example of the abnormality specific process which ECU performs. It is a timing chart which shows an example of change of the output state of a signal at the time of abnormal occurrence. It is a figure which shows the power supply system provided with the relay which isolate | separates the lower arm element connected to the battery of a low voltage side from a battery. It is a figure which shows a power supply system provided with the relay which isolate | separates an upper arm element from a battery while providing one battery and one boost converter. It is a figure which shows a power supply system provided with the relay which isolate | separates a lower arm element from a battery while providing one battery and one boost converter.

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

  In the present embodiment, an electric vehicle that can run by the function of motor generator MG without mounting an engine will be described as an exemplary embodiment of the electric vehicle. The electric vehicle is not limited to an electric vehicle, and may be a hybrid vehicle that can travel by the functions of both the engine and the motor generator MG.

[Configuration of electric vehicle]
FIG. 1 is a diagram showing a configuration of the electric vehicle 1. The electric vehicle 1 includes an ECU (Electronic Control Unit) 40, a motor generator MG, an inverter 30, a smoothing capacitor CH, and a power supply system 100.

  The ECU 40 corresponds to an embodiment of a “control device”. Although not shown, the ECU 40 includes a CPU (Central Processing Unit), a memory, and a buffer. The ECU 40 executes a predetermined calculation process based on a map and a program stored in the memory. And ECU40 controls each apparatus by outputting the instruction | command according to the arithmetic processing result. Note that a part or all of the ECU 40 may be configured to execute arithmetic processing by hardware such as an electronic circuit.

  Motor generator MG and inverter 30 correspond to an embodiment of “load”. Motor generator MG rotates drive wheels (not shown) by AC power supplied from inverter 30. Inverter 30 converts a direct current supplied from power supply system 100 via power supply line PL into a three-phase alternating current in response to a command from ECU 40 and outputs the same to motor generator MG.

  Smoothing capacitor CH is connected between power supply line PL and reference line NL, and smoothes voltage VH between power supply line PL and reference line NL. The smoothing capacitor CH is provided with a voltage sensor 43 that detects the voltage VH and outputs it to the ECU 40.

  Power supply system 100 is connected to two batteries B1 and B2 capable of supplying power to power supply line PL, smoothing capacitor C1 connected to both ends of the positive and negative electrodes of battery B1, and both ends of the positive and negative electrodes of battery B2. Smoothing capacitor C2, booster converter 10 provided between battery B1 and feed line PL and reference line NL, boost converter 20 provided between battery B2 and feed line PL and reference line NL, Is provided.

  Battery B1 corresponds to one embodiment of “power storage device”, and battery B2 corresponds to one embodiment of “other power storage device”. Battery B1 and battery B2 are DC power sources configured to be chargeable / dischargeable, and include, 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. . Battery B1 and battery B2 may be configured to be able to be charged using external electric power. For example, the battery B1 and the battery B2 are connected to a charger that can be connected to an external power supply, and power is supplied from the external power supply to the battery B1 and the battery B2 when the user connects the charger to the external power supply. It may be a thing.

  Battery B2 is connected in parallel with battery B1 to power supply line PL. In the present embodiment, battery B2 can supply power having a higher voltage than battery B1 to power supply line PL.

  Smoothing capacitor C1 smoothes voltage VB1 between the terminals of battery B1. The battery B1 is provided with a voltage sensor 41 that detects the voltage VB1 and outputs it to the ECU 40.

  Smoothing capacitor C2 smoothes voltage VB2 between the terminals of battery B2. The battery B2 is provided with a voltage sensor 42 that detects the voltage VB2 and outputs it to the ECU 40.

  Boost converter 10 corresponds to an embodiment of a “voltage converter”. Boost converter 10 boosts the voltage of battery B1 and supplies power to power supply line PL.

  Boost converter 10 includes an upper arm element including switching element Q1 and diode D1 provided between the positive electrode of battery B1 and power supply line PL, a path connecting the positive electrode of battery B1 and switching element Q1, and the battery. A lower arm element including a switching element Q2 and a diode D2 provided between the negative electrode of B1. More specifically, one end of reactor L1 is connected to the positive electrode of battery B1, and an upper arm element is provided between the other end of reactor L1 and feed line PL. A lower arm element is provided between the other end of reactor L1 and the negative electrode of battery B1. Hereinafter, the end of reactor L1 connected to the positive electrode of battery B1 is referred to as “one end of reactor L1”, and the end of reactor L1 connected to switching element Q2 is also referred to as “the other end of reactor L1”.

  The switching element Q1 corresponds to one embodiment of “an upper switching element” and “at least one switching element”. Switching element Q1 is formed of an IGBT element. The collector of the switching element Q1 is connected to the feed line PL via the supply line PL1. The supply line PL1 is a line that supplies power from the battery B1 to the power supply line PL. The cathode of the diode D1 is connected to the collector of the switching element Q1. The anode of the diode D1 is connected to the emitter of the switching element Q1.

  The switching element Q2 corresponds to an embodiment of a “lower switching element”. Switching element Q2 is formed of an IGBT element. The collector of switching element Q2 is connected to the other end of reactor L1. The emitter of switching element Q2 is connected to the negative electrode of battery B1. The cathode of the diode D2 is connected to the collector of the switching element Q2. The anode of the diode D2 is connected to the emitter of the switching element Q2.

  Boost converter 10 having such a configuration boosts the voltage of battery B1 in accordance with a command output from ECU 40 based on voltage VB1 detected by voltage sensor 41 and voltage VH detected by voltage sensor 43. To supply power to the power supply line PL.

  For example, in boost converter 10 during the boosting operation, switching element Q1 is maintained in the off state, and switching element Q2 is repeatedly controlled between the on state and the off state at a predetermined duty ratio. When the switching element is in the off state, the switching element is in an open state, i.e., a non-conducting state, and when the switching element is in the on state, the switching element is in a closed state, i.e., in a conducting state. As a result, the current flowing when switching element Q2 is turned on is stored as electromagnetic energy in reactor L1, and when switching element Q2 transitions to the off state, the stored electromagnetic energy is superimposed on the discharge current, so that the voltage of battery B1 is increased. Boosted.

  Boost converter 20 corresponds to an embodiment of “another voltage conversion device”. Boost converter 20 is connected in parallel with boost converter 10 with respect to power supply line PL. Boost converter 20 boosts the voltage of battery B2 and supplies power to power supply line PL.

  Boost converter 20 includes an upper arm element including switching element Q3 and diode D3 provided between the positive electrode of battery B2 and power supply line PL, a path connecting the positive electrode of battery B2 and switching element Q3, and the battery. And a lower arm element including a switching element Q4 and a diode D4 provided between the negative electrode of B2. More specifically, one end of reactor L2 is connected to the positive electrode of battery B2, and an upper arm element is provided between the other end of reactor L2 and feed line PL. A lower arm element is provided between the other end of reactor L2 and the negative electrode of battery B2.

  Since the upper arm element (switching element Q3, diode D3) of boost converter 20 has the same configuration as the upper arm element (switching element Q1, diode D1) of boost converter 10 described above, description thereof will not be repeated. Further, since the lower arm element (switching element Q4, diode D4) of boost converter 20 has the same configuration as the lower arm element (switching element Q2, diode D2) of boost converter 10 described above, description thereof will not be repeated.

  Boost converter 20 having such a configuration boosts the voltage of battery B2 in accordance with a command output from ECU 40 based on voltage VB2 detected by voltage sensor 42 and voltage VH detected by voltage sensor 43. To supply power to the power supply line PL. Since the boost operation of boost converter 20 is the same as the boost operation of boost converter 10, description thereof will not be repeated.

  Boost converters 10 and 20 operate as a booster circuit. However, when electric power generated by motor MG at the time of regenerative braking of electric vehicle 1 is returned to batteries B1 and B2, it may operate as a step-down circuit.

  As described above, by using the two batteries B1 and B2 and the two boost converters 10 and 20, it is possible to stably ensure sufficient power for operating the motor MG. Further, even when the storage state of one battery deteriorates or a short circuit failure occurs in the switching element, it is possible to supply the power of the other battery to the power supply line PL.

  In boost converter 10, fuse 50 is provided in a path between supply line PL <b> 2 that supplies power from battery B <b> 2 to power supply line PL and connection point X of power supply line PL and the other end of reactor L <b> 1. Yes. In the present embodiment, fuse 50 is provided between connection point Y between the other end of reactor L1 and switching element Q2 and switching element Q1.

  The fuse 50 corresponds to an embodiment of a “switching device”. The fuse 50 is either in a disconnected state in which the upper arm including the switching element Q1 is disconnected from the battery B1 or in a connected state in which the upper arm including the switching element Q1 is connected to the battery B1 in accordance with a command output from the ECU 40. It can be switched to a state.

  The fuse 50 includes a switching element Q5 composed of an IGBT element having the same specification as the switching element Q1, a switching element Q6 composed of an IGBT element having the same specification as the switching element Q2, a diode D5 having the same specification as the diode D1, A diode D2 and a diode D6 having the same specifications are provided. Note that the same specification means that the parts have the same shape (for example, the same package) and have the same performance. That is, if the parts have the same specifications, the parts can be shared. Switching elements Q1 to Q6 are not limited to IGBT elements, and may be configured by MOSFETs or bipolar transistors.

  The collector of switching element Q5 and the collector of switching element Q6 are connected to the emitter of switching element Q1. The emitter of switching element Q5 and the emitter of switching element Q6 are connected to the other end of reactor L1 and the collector of switching element Q2. The cathode of diode D5 is connected to the collector of switching element Q5. The anode of diode D5 is connected to the emitter of switching element Q5. The cathode of diode D6 is connected to the collector of switching element Q6. The anode of diode D6 is connected to the emitter of switching element Q6.

  In power supply system 100, while boost converter 10 is operating normally, a short-circuit current does not occur from battery B2 on the high voltage side toward battery B1 on the low voltage side. However, when the fuse 50 is in the connected state, if the short-circuit fault of the switching element Q1 occurs in the boost converter 10 (the fault that the collector-emitter of the switching element Q1 is short-circuited and always kept on), the battery There is a possibility that a short-circuit current may be generated from the battery B2 to the battery B1 due to the voltage applied to the connection point X by the battery B2 having a higher voltage than B1.

  Therefore, when the switching element Q1 is normal, the ECU 40 turns on the switching element Q5 and the switching element Q6 to connect the fuse 50. On the other hand, when the switching element Q1 has any abnormality, the ECU 40 In addition, the switching element Q6 is turned off to temporarily turn off the fuse 50. As described above, even when the abnormality that has occurred in the switching element Q1 is a short-circuit failure, it is possible to prevent the occurrence of a short-circuit current from the battery B2 toward the battery B1 by disconnecting the switching element Q1 from the battery B1.

  In addition, since fuse 50 interrupts the path between connection point X and the other end of reactor L1, the voltage of battery B2 is prevented from being applied to reactor L1 and damaging reactor L1. It is possible to prevent the voltage B2 from being applied to the smoothing capacitor C1.

[Configuration of drive module]
A drive module 70 is connected to the switching element Q1. The drive module 70 is connected not only to the switching element Q1, but also to each switching element included in the switching elements Q2 to Q6 and the inverter 30. Hereinafter, the driving module 70 connected to the switching element Q1 will be described. explain.

  FIG. 2 is a diagram illustrating the configuration of the drive module 70. The drive module 70 includes a drive power supply 77, a current sensor 71, a temperature sensor 72, and a drive IC 75. The drive IC 75 corresponds to an embodiment of an “abnormal signal output device”.

  The drive power supply 77 supplies power from another battery (not shown) to the drive IC 75. The current sensor 71 includes, for example, a resistor, detects a current flowing through the emitter of the switching element Q1, and outputs it to the drive IC 75. The temperature sensor 72 includes, for example, a diode, detects the temperature of the switching element Q1, and outputs it to the drive IC 75.

  The ECU 40 outputs a gate signal for closing the switching element Q1 to the switching element Q1. The gate signal corresponds to one embodiment of the “ON signal”. The gate signal output from the ECU 40 is input to the switching element Q1 via the drive IC 75. When the gate signal is input to the switching element Q1, the gate signal is turned on. When the gate signal is not input to the switching element Q1, the gate signal is turned off. The drive IC 75 applies a predetermined voltage (for example, 15V) to the gate of the switching element Q1 using the power supplied from the drive power supply 77 when the gate signal is received from the ECU 40, that is, when the gate signal is in the ON state. To do. When a predetermined voltage is applied to the gate, the switching element Q1 is turned on. On the other hand, when the gate signal is in an off state, a predetermined voltage is not applied to the gate, so that the switching element Q1 is in an off state.

  The drive IC 75 outputs a common fail signal when a short circuit failure occurs and when an abnormality different from the short circuit failure occurs. The fail signal corresponds to one embodiment of an “abnormal signal”. When the fail signal is output, the fail signal is turned on. When the fail signal is not output, the fail signal is turned off.

  FIG. 3 is a diagram for explaining an output pattern of a fail signal. As shown in FIG. 3, when the fuse 50 is in the connected state, the drive IC 75 outputs a fail signal to the ECU 40 when an overcurrent that causes the current detected by the current sensor 71 to exceed a predetermined value occurs. (Pattern B in FIG. 3). The overcurrent occurs not only when a short circuit failure occurs in the switching element Q1, but also when an abnormality different from the short circuit failure (for example, a component failure other than the switching element Q1) occurs. On the other hand, when the fuse 50 is in the cut-off state, the drive IC 75 does not generate an overcurrent because no current flows through the switching element Q1, and does not output a fail signal.

  As shown in FIG. 3, when the fuse 50 is in the connected state, the drive IC 75 sends a fail signal to the ECU 40 when overheating occurs in which the temperature detected by the temperature sensor 72 becomes a predetermined value or more. Output (pattern C in FIG. 3). The overheating occurs not only when a short circuit failure occurs in the switching element Q1, but also when an abnormality different from the short circuit failure occurs. On the other hand, when the fuse 50 is in the cut-off state, the drive IC 75 does not cause overheating because no current flows through the switching element Q1, and does not output a fail signal.

  Further, as shown in FIG. 3, when the fuse 50 is connected and the gate signal is in the ON state, the drive IC 75 causes the ECU 40 to be informed when the output voltage of the drive power supply 77 drops below a predetermined value. A fail signal is output (pattern A in FIG. 3). Here, when the short-circuit failure of the switching element Q1 occurs, the gate-emitter is also short-circuited with the collector-emitter short-circuit. Therefore, in switching element Q1, when a gate signal is received from ECU 40 at the time of a short circuit failure, the output voltage of drive power supply 77 decreases due to a short circuit current flowing between the gate and the emitter. The drive IC 75 detects a decrease in the output voltage of the drive power supply 77. A decrease in the output voltage of drive power supply 77 is detected only when a short circuit failure occurs in switching element Q1. Note that the drive IC 75 outputs a fail signal in order to detect a decrease in the output voltage of the drive power supply 77 if the gate signal is in an on state even when the fuse 50 is in an interrupted state (pattern D in FIG. 3).

[Abnormality identification processing]
As described with reference to FIG. 3, the drive IC 75 outputs a common fail signal when a short circuit failure occurs and when an abnormality different from the short circuit failure occurs. Therefore, the ECU 40 cannot specify that the detected abnormality is a short-circuit failure of the switching element Q1 simply by receiving a fail signal when the fuse 50 is in the connected state. Therefore, even if the detected abnormality is different from the short-circuit fault, the possibility that the short-circuit fault has occurred cannot be ruled out and the fuse 50 cannot be connected again. It will remain disconnected from B1. For this reason, there is a problem that the power boosted by the boost converter 10 cannot be supplied to the power supply line PL again. Further, if the fuse 50 is maintained in the cut-off state in spite of the occurrence of the short-circuit failure of the switching element Q1, only the electric power from the battery B2 can be supplied to the power supply line PL, and the electric vehicle 1 Will not be able to continue running for a long time. Furthermore, there is a possibility that an abnormality such as a control failure may occur in the boost converter 20 connected to the battery B2.

  In view of the above-described problem, the ECU 40 determines whether or not the detected abnormality is a short-circuit failure of the switching element Q1 when the failure signal is received from the drive IC 75 by executing the abnormality specifying process shown in FIG. When the detected abnormality is different from the short-circuit failure, the fuse 50 is switched from the cut-off state to the connected state. Details will be described below.

  As shown by the pattern D in FIG. 3, in the drive IC 75, when the fuse 50 is in the cut-off state and the gate signal is in the on-state, the output voltage of the drive power supply 77 decreases when the abnormality is a short-circuit fault. Therefore, a fail signal is output. On the other hand, when the abnormality is an abnormality different from the short-circuit failure, the output voltage of the drive power supply 77 does not decrease, so that a fail signal is not output. Utilizing this, when the ECU 40 receives a fail signal from the drive IC 75, the ECU 40 switches the fuse 50 from the connected state to the cut-off state, and then outputs a gate signal to the switching element Q1 in which the abnormality is detected. Such processing by the ECU 40 is also referred to as confirmation processing. Thereby, ECU40 produces the condition of the pattern D shown in FIG. Then, the ECU 40 specifies that the detected abnormality is a short-circuit failure when the fail signal is received again from the drive IC 75 during the confirmation process, while the detected abnormality is not received again when the fail signal is not received again. The fuse 50 is switched from the cut-off state to the connected state by specifying that the abnormality is different from the short-circuit failure. As a result, even when a common fail signal is output when a short-circuit failure occurs and when an abnormality different from the short-circuit failure occurs, the detected abnormality is different from the short-circuit failure. If it is abnormal, the power boosted by boost converter 10 can be supplied again to power supply line PL.

  The abnormality specifying process will be described in detail with reference to FIGS. 4 and 5. FIG. 4 is a flowchart illustrating an example of the abnormality specifying process executed by the ECU 40. Here, an abnormality identifying process for identifying an abnormality that has occurred in the switching element Q1 will be described. Each step (hereinafter abbreviated as S) in the flowchart shown in FIG. 4 is basically realized by software processing by the ECU 40, but may be realized by hardware (electronic circuit) produced in the ECU 40. Good. FIG. 5 shows an example of a change in the signal output state when an abnormality different from a short-circuit failure occurs in the upper arm element connected to the low-voltage side battery B1, that is, the switching element Q1.

  The process of FIG. 4 is started when the fuse 50 is in a connected state. As shown in FIG. 4, the ECU 40 determines whether or not the fail signal has been turned on (S10). The ECU 40 specifies that the fail signal is on while receiving the fail signal, and specifies that the fail signal is off while not receiving the fail signal.

  ECU40 complete | finishes this process, when a failure signal is an OFF state (it is NO at S10).

  On the other hand, when the fail signal is in the ON state (YES in S10), the ECU 40 cannot specify whether the detected abnormality is a short-circuit failure of the switching element Q1 at this time. A shut-off state is set (S11). For example, as shown in FIG. 5, when the fail signal is turned on at timing t1, the ECU 40 puts the fuse 50 into a cut-off state.

  Thereby, even if a short circuit failure of the switching element Q1 occurs, it is possible to prevent the occurrence of a short circuit current from the battery B2 to the battery B1. Further, when the fuse 50 is cut off, no current flows through the switching element Q1, so no overcurrent or overheating occurs, and the fail signal gradually switches from the on state to the off state.

  Moreover, if ECU40 is outputting the gate signal when fuse 50 is made into the interruption | blocking state, it will stop the output of a gate signal.

  Next, the ECU 40 determines whether or not a gate signal can be output to the switching element Q1 (S12). For example, the ECU 40 determines whether or not the fail signal is switched from the on state to the off state, and the switching element Q1 is in a state where it can accept the gate signal via the drive IC 75. For example, as shown in FIG. 5, the ECU 40 determines whether or not the fail signal is switched from the on state to the off state at timing t2, and the switching element Q1 is in a state in which the gate signal can be received in a predetermined period thereafter. To do.

  When ECU 40 is not in a state where a gate signal can be output to switching element Q1 (NO in S12), ECU 40 repeats the process of S12.

  On the other hand, when the ECU 40 is in a state in which a gate signal can be output to the switching element Q1 (YES in S12), the ECU 40 performs a confirmation process of outputting the gate signal to the switching element Q1 while maintaining the fuse 50 in the cut-off state ( S13). For example, as shown in FIG. 5, when the switching element Q1 becomes capable of accepting the gate signal at timing t3, the ECU 40 outputs the gate signal to the switching element Q1 while maintaining the fuse 50 in the cut-off state. Thereby, ECU40 produces the condition of the pattern D shown in FIG.

  After S13, the ECU 40 receives the fail signal from the drive IC 75 again during the confirmation process and determines whether or not the fail signal has been turned on (S14).

  When the fail signal remains off (NO in S14) when the ECU 40 outputs the gate signal to the switching element Q1 while maintaining the fuse 50 in the cut-off state as in the pattern D, the switching element It is determined that an abnormality different from the short-circuit failure has occurred in Q1, and the fuse 50 is again connected to enable boosting by the boost converter 10 (S15), and this process is terminated. For example, as shown in FIG. 5, if the fail signal remains off even when the gate signal is output to the switching element Q1 at the timing t3, the ECU 40 generates an abnormality different from the short-circuit failure. Then, the fuse 50 is again connected at timing t5.

  Thereby, when the detected abnormality is an abnormality different from the short-circuit failure, the electric power boosted by boost converter 10 can be supplied again to power supply line PL.

  On the other hand, the ECU 40 outputs the gate signal to the switching element Q1 while keeping the fuse 50 in the cut-off state as in the pattern D, so that the fail signal is turned on again (YES in S14). The process is terminated while specifying that a short circuit failure has occurred in Q1 and maintaining the fuse 50 in the cut-off state.

  As described above, when the ECU 40 according to the present embodiment receives a fail signal from the drive IC 75 when the fuse 50 is in the connected state, the abnormality is detected after the fuse 50 is switched from the connected state to the disconnected state. When the confirmation process for outputting the gate signal to the switching element Q1 is performed and the fail signal is not received again from the drive IC 75 during the confirmation process, the detected abnormality is identified as an abnormality different from the short-circuit fault, and the fuse 50 Switch from blocked to connected. As a result, the detected abnormality is short-circuited even when a common failure signal is output when a short-circuit failure occurs in the switching element Q1 and when a failure different from the short-circuit failure occurs. When the abnormality is different from the failure, the power boosted by the boost converter 10 can be supplied again to the power supply line PL.

[Modification]
In the present embodiment, fuse 50 includes switching elements Q5 and Q6 made of IGBT elements and diodes D5 and D6. However, the fuse 50 may be composed of other members. For example, as shown in FIG. 6, the fuse 50 may be configured by a relay 60.

  In the present embodiment, the abnormality specifying process for specifying an abnormality that has occurred in switching element Q1 included in the upper arm element of boost converter 10 has been described with reference to FIGS. 4 and 5. However, not limited to switching element Q1, switching element Q2 included in the lower arm element of boost converter 10, switching element Q3 included in the upper arm element of boost converter 20, and switching element included in the lower arm element of boost converter 20 In any of Q4, the abnormality identification process in the present embodiment may be applied to identify the abnormality that has occurred. That is, any of switching element Q2, switching element Q3, and switching element Q4 may correspond to an embodiment of “at least one switching element”.

  For example, as shown in FIG. 6, a fuse 50 may be provided between the connection point Y and the switching element Q2. As a result, even if a short circuit failure of the switching element Q2 occurs, the switching element Q2 is electrically disconnected from the battery B1 by the fuse 50 being cut off, so that the positive electrode of the battery B1 Occurrence of a short circuit current flowing between the negative electrode and the negative electrode can be prevented. Further, by performing the abnormality identification process, if the confirmation process is performed on the switching element Q2 when the fuse 50 is in the cut-off state, it is possible to identify whether or not a short-circuit failure of the switching element Q2 has occurred. it can.

  In the present embodiment, power supply system 100 includes two batteries B1 and B2 and two boost converters 10 and 20. However, as illustrated in FIG. 7, the power supply system 100 may include one battery B <b> 1 and one boost converter 10. Furthermore, after configuring in this way, a fuse 50 may be provided between the connection point Y and the switching element Q1. Even in this configuration, if the confirmation process is performed on the switching element Q1 when the fuse 50 is in the cut-off state by executing the abnormality specifying process, whether or not a short-circuit failure has occurred in the switching element Q1. Can be identified.

  Further, as shown in FIG. 8, the power supply system 100 includes one battery B1 and one boost converter 10, and a fuse 50 may be provided between the connection point Y and the switching element Q2. . Even in this configuration, if the confirmation process is performed on the switching element Q2 when the fuse 50 is in the cut-off state by executing the abnormality specifying process, whether or not a short-circuit failure of the switching element Q2 has occurred. Can be identified.

  Further, the above-described embodiment and its modification examples can be combined as appropriate.

  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.

  DESCRIPTION OF SYMBOLS 1 Electric vehicle 10,20 Boost converter, 30 Inverter, 40 ECU, 41,42,43 Voltage sensor, 50 fuse, 70 Drive module, 71 Current sensor, 72 Temperature sensor, 75 Drive IC, 77 Drive power supply, 100 Power supply system B1, B2 battery, L1, L2 reactor, Q1, Q2, Q3, Q4, Q5, Q6 switching element, D1, D2, D3, D4, D5, D6 diode.

Claims (1)

A power supply system for supplying power to a load,
A power storage device capable of supplying power to a power supply line to the load;
Upper switching element provided between the positive electrode of the power storage device and the power supply line, and lower switching provided between a path connecting the positive electrode of the power storage device and the upper switching element and the negative electrode of the power storage device A voltage conversion device including an element;
Switchable between a shut-off state in which at least one of the upper switching element and the lower switching element is disconnected from the power storage device and a connection state in which the at least one switching element is connected to the power storage device A switchgear configured to,
A control device for controlling the upper switching element, the lower switching element, and the switchgear;
An abnormality signal output device that outputs an abnormality signal to the control device when an abnormality of the at least one switching element is detected;
The controller is
When the abnormal signal is received from the abnormal signal output device, an on signal for closing the switching element is applied to the at least one switching element in which an abnormality is detected after the switchgear is switched from the connected state to the disconnected state. A power supply system that outputs and identifies the abnormality as an abnormality different from a short-circuit failure when the abnormality signal is not received again from the abnormality signal output device, and switches the switchgear from the disconnected state to the connected state .