JP2006304408A - Power unit, and method for controlling the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a power unit capable of protecting a pre-charge circuit when a semiconductor relay is used for a pre-charge relay. <P>SOLUTION: A system main relay SMR1 being the pre-charge relay comprises a semiconductor relay. A current sensor 32 detects a current I1 flowing in the pre-charge circuit which comprises the system main relay SMR1 and a limit resistor R. During regeneration operation, a control unit 20 determines that the system main relay SMR2 is opened and troubled when the current I1 exceeds a specified reference value Ith. Then, the control unit 20 stops the invertor 10 and turns off the system main relay SMR3. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power supply device and a method for controlling the power supply device, and more particularly, to a power supply device including a precharge relay that is turned on during a precharge process that is executed at the time of system startup, and a control method for the power supply device.

  In recent years, hybrid vehicles (electric vehicles) and electric vehicles (electric vehicles) have attracted attention as environmentally friendly vehicles. A hybrid vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as a power source in addition to a conventional engine. An electric vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as a power source.

  In this hybrid vehicle or the like, a system main relay is generally provided between a DC power source and a load drive circuit such as an inverter. The system main relay has a precharge relay and a limiting resistor connected in series to the positive electrode of the DC power supply, and a first relay connected in parallel to the precharge relay and the limiting resistor to the positive electrode of the DC power supply. And a second relay connected to the negative electrode of the DC power supply are known (see, for example, Patent Document 1).

The limiting resistor is provided to prevent the inrush current from flowing. That is, if the DC power supply is directly connected directly to the electric circuit, an inrush current flows from the DC power supply to an uncharged capacitor that smoothes the DC voltage from the DC power supply, and the system main relay may be welded. Therefore, the precharge relay connected in series with the limiting resistor is first turned on to precharge the capacitor while limiting the current from the DC power supply, and after the precharge is completed, the first relay is turned on and the precharge relay is turned on. By turning off, inrush current can be prevented (hereinafter, this process is referred to as “precharge process”).
JP 2000-134707 A JP 2003-324801 A

  In the prior art disclosed in Japanese Patent Laid-Open No. 2000-134707 described above, a mechanical relay is generally used as the system main relay. Here, since many electric components are mounted in a hybrid vehicle or an electric vehicle, cost reduction and miniaturization of each component are required. The system main relay is also required to be reduced in cost and size. Therefore, it is conceivable to use a low-cost and small-sized semiconductor relay (transistor) instead of the mechanical relay as the precharging relay used only for the precharging process.

  In a semiconductor relay, a diode connected in antiparallel to the transistor is generally provided to protect the transistor. For this reason, both ends of the precharging relay are in an electrically connected state via the diode even in a process other than the precharging process in which the transistor is turned off. However, since the limiting resistor is connected in series to the precharging relay, if the first relay is on, a current flows through the first relay having a small resistance, and the precharging relay and the limiting resistor No current flows through the precharge circuit.

  However, when an abnormality occurs in the first relay, for example, when the first relay reaches an open failure, a current flows through the precharge circuit. Since this current can be larger than the precharge current, the precharge circuit may be damaged.

  Accordingly, the present invention has been made to solve such a problem, and an object thereof is to provide a power supply device capable of protecting a precharge circuit when a semiconductor relay is used as a precharge relay. .

  Another object of the present invention is to provide a method for controlling a power supply apparatus capable of protecting a precharge circuit when a semiconductor relay is used as the precharge relay.

  According to the present invention, the power supply device is a power supply device that transfers power to and from the load drive circuit, and is provided between the DC power supply, one pole of the DC power supply, and the load drive circuit. A precharge relay including a diode connected in parallel; a resistance element connected in series with the precharge relay between one pole of the DC power supply and the load driving circuit; and one pole of the DC power supply and the load A first relay connected between the precharge relay and the resistance element connected in series, and a second relay provided between the other pole of the DC power supply and the load drive circuit. A first current detecting means for detecting a current flowing through the precharge relay and the resistance element connected in series, and the first current detecting means when the transistor is turned off. An abnormality detecting means for detecting an abnormality of the power supply device based on the output current; and a control means for outputting a command to stop the load driving circuit to the load driving circuit when an abnormality is detected by the abnormality detecting means; Is provided.

  In the power supply device according to the present invention, the precharge relay used in the precharge process is formed of a transistor. A diode for protecting the transistor is connected in parallel to the transistor. Even if the transistor is turned off by the diode after the precharge process is completed, both ends of the precharge relay are in an electrically connected state. However, when the DC power supply and the load drive circuit are conducted through the first relay, the current route through the first relay is the current through the precharge circuit including the precharge relay and the resistance element. Since the resistance is much smaller than the root, almost no current flows in the precharge circuit. However, when an abnormality occurs in the power supply device and the resistance value of the current route through the first relay increases (for example, disconnection of the power supply line or open failure of the first relay), the power supply device is in an electrically connected state. An unexpectedly large current can flow through the precharge circuit. Therefore, in this power supply device, a current flowing through the precharge circuit is detected, and an abnormality of the power supply device is detected based on the detected current. When an abnormality is detected, the control means stops the load driving circuit, so that a large current does not flow through the precharge circuit.

  Therefore, according to the power supply device of the present invention, it is possible to reliably protect the precharge circuit including the precharge relay including the transistor.

  Preferably, the abnormality detection unit detects that an abnormality that causes the first relay to be opened occurs when a current larger than a predetermined reference value is detected by the first current detection unit.

  In this power supply apparatus, when the first relay reaches an open failure, a current flows through the precharge circuit, and the abnormality detection means detects a current larger than a predetermined reference value by the first current detection means. Since the open failure of the first relay is detected and the control means stops the load driving circuit accordingly, a large current does not flow through the precharge circuit. Therefore, according to this power supply device, the precharge circuit can be reliably protected.

  Preferably, the power supply device further includes second current detection means for detecting a current input / output to / from the DC power supply, and the abnormality detection means detects the first and second current detection currents larger than a predetermined reference value. When detected by the means, it is detected that an abnormality has occurred in which the first relay is open.

  In this power supply apparatus, since the second current detection means is also used for detecting the abnormality of the first relay, it is possible to prevent the load drive circuit from being erroneously stopped due to the erroneous detection of the first current detection means. Therefore, according to this power supply device, operation reliability is improved.

  Preferably, when an abnormality is detected by the abnormality detection unit, the control unit further outputs a command for instructing opening of the second relay to the second relay.

  In this power supply device, when an abnormality is detected, the control means stops the load drive circuit and turns off the second relay to cut off the electric circuit between the DC power supply and the load drive circuit. Therefore, according to this power supply device, the precharge circuit can be more reliably protected.

  According to the present invention, a method for controlling a power supply apparatus includes a DC power supply, a precharge that is provided between one pole of the DC power supply and a load drive circuit, and includes a transistor and a diode connected in parallel to the transistor. Relay, a resistance element connected in series with the precharge relay between one pole of the DC power supply and the load driving circuit, and a series connection between one pole of the DC power supply and the load driving circuit. A first relay connected in parallel to the connected precharge relay and the resistance element; a second relay provided between the other pole of the DC power supply and the load driving circuit; and a precharge connected in series And a first current detection means for detecting a current flowing through the resistance element, the control method comprising: a first current detection when the transistor is turned off; A first step of detecting an abnormality of the power supply device based on the current detected by the stage; and a second step of outputting an instruction to stop the load drive circuit to the load drive circuit when an abnormality of the power supply device is detected. Steps.

  In the control method of the power supply device according to the present invention, the load drive circuit is stopped when the abnormality of the power supply device is detected based on the current detected by the first current detection means, and therefore, the precharge relay and the resistance element are included. No large current flows through the precharge circuit. Therefore, according to the control method of the power supply device according to the present invention, the precharge circuit including the precharge relay including the transistor can be reliably protected.

  Preferably, in the first step, when a current larger than a predetermined reference value is detected by the first current detecting means, it is detected that an abnormality that causes the first relay to be opened has occurred.

  In this power supply device control method, when the first relay reaches an open failure, a current is passed through the precharge circuit. When a current larger than a predetermined reference value is detected by the first current detection means, Since the open failure of the relay 1 is detected and the load driving circuit is stopped accordingly, a large current does not flow through the precharge circuit. Therefore, according to the control method of the power supply device, the precharge circuit can be reliably protected.

  Preferably, the power supply device further includes second current detection means for detecting a current input / output to / from the DC power supply, and the first step of the control method is that the current greater than a predetermined reference value is the first and first currents. When detected by the second current detection means, it is detected that an abnormality that causes the first relay to be in an open state has occurred.

  In the control method of the power supply apparatus, the second current detection means is also used for detecting the abnormality of the first relay, so that the load drive circuit is not erroneously stopped due to the erroneous detection of the first current detection means. Therefore, according to the control method of the power supply device, the control reliability is improved.

  Preferably, the control method further includes a third step of outputting a command for instructing opening of the second relay to the second relay when an abnormality of the power supply device is detected in the first step.

  In this power supply device control method, when an abnormality of the power supply device is detected, the load drive circuit is stopped and the second relay is turned off to cut off the electric circuit between the DC power supply and the load drive circuit. Therefore, according to the method for controlling the power supply device, the precharge circuit can be more reliably protected.

  According to the present invention, the precharge circuit can be reliably protected when a semiconductor relay (transistor) is used as the precharge relay.

  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.

[Embodiment 1]
1 is a schematic block diagram of a load driving device including a power supply device according to Embodiment 1 of the present invention. Referring to FIG. 1, load driving device 100 includes a battery B, system main relays SMR1 to SMR3, a limiting resistor R, a capacitor C, an inverter 10, a control device 20, a power supply line PL, and a ground line. SL, voltage sensor 30, and current sensor 32 are provided.

  The load driving device 100 is mounted on a hybrid vehicle or an electric vehicle. Motor generator MG is connected to drive wheels (not shown), and is incorporated into a hybrid vehicle or an electric vehicle as an electric motor for driving the drive wheels. Motor generator MG may be incorporated in a hybrid vehicle so as to be connected to an engine (not shown), operate as an electric motor that can start the engine, and operate as a generator driven by the engine.

  Limiting resistor R and system main relay SMR1 are connected in series between the positive electrode of battery B and power supply line PL. System main relay SMR1 includes a transistor Q and a diode D connected in parallel to transistor Q. The diode D has an anode connected to the power line PL side and a cathode connected to the limiting resistor R side.

  System main relay SMR2 is connected in parallel with limiting resistor R and system main relay SMR1 between the positive electrode of battery B and power supply line PL. System main relay SMR3 is connected between the negative electrode of battery B and ground line SL.

  Capacitor C is connected between power supply line PL and ground line SL. Inverter 10 includes a U-phase arm, a V-phase arm, and a W-phase arm that are connected in parallel between power supply line PL and ground line SL (not shown). The connection point between the upper arm and the lower arm in each U, V, W phase arm is connected to each U, V, W phase coil (not shown) of motor generator MG.

  The battery B is a DC power source that can be charged and discharged, and is composed of, for example, a secondary battery such as nickel metal hydride or lithium ion. Battery B generates a DC voltage and supplies it to power supply line PL. Battery B is charged by inverter 10 that converts the AC voltage generated by motor generator MG into a DC voltage during the regenerative operation.

  System main relays SMR2 and SMR3 are mechanical relays. On the other hand, the system main relay SMR1 is composed of a semiconductor relay (transistor Q) as described above. System main relays SMR1 to SMR3 are turned on / off by signals SE1 to SE3 from control device 20, respectively. Specifically, transistor Q of system main relay SMR1 and system main relays SMR2 and SMR3 are turned on by signals SE1 to SE3 at H (logic high) level, respectively, and signals SE1 to SE3 at L (logic low) level, respectively. Turned off.

  Current sensor 32 detects a current I1 flowing through system main relay SMR1 and limiting resistor R, and outputs the detected current I1 to control device 20. Capacitor C smoothes voltage fluctuations between power supply line PL and ground line SL. The voltage sensor 30 detects the voltage VM across the capacitor C and outputs the detected voltage VM to the control device 20.

  Inverter 10 converts a DC voltage received from power supply line PL into an AC voltage based on signal PWMI from control device 20 and outputs the AC voltage to motor generator MG. Inverter 10 also converts an AC voltage generated by motor generator MG into a DC voltage based on signal PWMC from control device 20 and supplies it to power supply line PL. Further, the inverter 10 is stopped by a signal SDOWN from the control device 20. Specifically, inverter 10 stops when receiving H level signal SDOWN.

  Control device 20 receives voltage VM from voltage sensor 30 and current I1 from current sensor 32. Control device 20 receives a start signal ST instructing the start of operation of load driving device 100 and torque command value TR of motor generator MG from an external ECU (Electronic Control Unit) (not shown). Furthermore, control device 20 receives each phase motor current MCRT of motor generator MG. Each phase motor current MCRT is detected by a current sensor (not shown).

  When control device 20 receives H-level start signal ST, control device 20 controls on / off of system main relays SMR1 to SMR3 by a method to be described later, and executes precharge processing for precharging capacitor C in an uncharged state. .

  Control device 20 starts control for driving motor generator MG when precharging of capacitor C is completed. Specifically, control device 20 regeneratively drives signal PWMI or motor generator MG for powering driving motor generator MG based on torque command value TR of motor generator MG, each phase motor current MCRT, and voltage VM. Signal PWMC is generated, and the generated signal PWMI or signal PWMC is output to inverter 10.

  Further, when motor generator MG is driven, control device 20 protects the precharge circuit including limiting resistor R and system main relay SMR1 by a method described later based on current I1 from current sensor 32. Execute protection control.

  FIG. 2 is a flowchart of the precharge process performed by the control device 20 shown in FIG. Referring to FIG. 2, upon receiving an H level start signal ST (step S10), control device 20 generates H level signals SE1 and SE3 and outputs them to system main relays SMR1 and SMR3, respectively. The transistor Q of the relay SMR1 and the system main relay SMR3 are turned on (step S20). As a result, the precharge from the battery B to the capacitor C is started via the precharge circuit including the limiting resistor R and the transistor Q.

  When the precharging of the capacitor C is started, the control device 20 determines whether or not the voltage VM from the voltage sensor 30 has exceeded a predetermined precharge voltage Vchg (step S30). When control device 20 determines that voltage VM exceeds precharge voltage Vchg (YES in step S30), control device 20 generates H level signal SE2 and outputs it to system main relay SMR2, and turns on system main relay SMR2 (step S30). S40). Thereafter, control device 20 generates L level signal SE1 and outputs it to system main relay SMR1, and turns off transistor Q of system main relay SMR1 (step S50). Thereby, a series of precharge processing is completed.

  FIG. 3 is a flowchart of protection control by the control device 20 shown in FIG. This protection control is executed when the inverter 10 is driven, that is, after completion of the precharge process shown in FIG. Referring to FIG. 3, control device 20 determines whether or not current I1 from current sensor 32 exceeds a predetermined reference value Ith (step S110). The predetermined reference value Ith is set to an appropriate value larger than the maximum value of the current that can flow to the precharge circuit side when the system main relay SMR2 is on. When control device 20 determines that current I1 is equal to or smaller than predetermined reference value Ith (NO in step S110), it determines that system main relay SMR2 is normally turned on, and ends a series of processing. .

  On the other hand, when control device 20 determines that current I1 exceeds predetermined reference value Ith (YES in step S110), it determines that system main relay SMR2 has an open failure. The control device 20 outputs an H level signal SDOWN to the inverter 10 in order to protect the precharge circuit because a large current may flow through the precharge circuit when the system main relay SMR2 fails to open. The inverter 10 is stopped (step S120).

  When control device 20 stops inverter 10, it outputs L level signal SE3 to system main relay SMR3 to turn off system main relay SMR3 (step S130). Then, a series of processing ends. The reason why the system main relay SMR3 is further turned off in addition to the stop of the inverter 10 is to completely cut off the electric path between the battery B and the inverter 10 to ensure the protection of the precharge circuit.

  With reference to FIG. 1 again, the overall operation of the load driving device 100 will be described. When receiving the H level start signal ST from the start switch, the control device 20 executes the precharge process by the method described above.

  Thereafter, control device 20 generates signal PWMI or signal PWMC based on torque command value TR, each phase motor current and voltage VM, and outputs the generated signal PWMI or signal PWMC to inverter 10. When inverter 10 receives signal PWMI from control device 20, inverter 10 converts the DC voltage from power supply line PL into an AC voltage based on the received signal PWMI, and outputs the AC voltage to motor generator MG. When inverter 10 receives signal PWMC from control device 20, inverter 10 converts the AC voltage regenerated by motor generator MG into a DC voltage based on the received signal PWMC, and supplies it to power line PL.

  In the load driving apparatus 100, the system main relay SMR1 that is turned on during the precharge process is composed of a semiconductor relay (transistor Q) instead of a mechanical relay that is generally used. A protective diode D is connected to the transistor Q in parallel. This diode D can flow a regenerative current from the inverter 10 even in a case other than the precharge process. However, if the system main relay SMR2 is normally turned on, a current flows through the system main relay SMR2. No current flows through the diode D and the limiting resistor R. On the other hand, when the system main relay SMR2 fails to open, a regenerative current flows from the power supply line PL to the limiting resistor R and the battery B via the diode D, which may damage the diode D and the limiting resistor R.

  Therefore, the control device 20 performs protection control of the precharge circuit by the method described above. That is, when detecting an open failure of system main relay SMR2 based on current I1 from current sensor 32, control device 20 stops inverter 10 and turns off system main relay SMR3. This prevents a regenerative current from flowing through the diode D and the limiting resistor R.

  As described above, according to the first embodiment, the precharge circuit composed of the system main relay SMR1 and the limiting resistor R can be protected.

[Embodiment 2]
FIG. 4 is a schematic block diagram of a load driving device including a power supply device according to Embodiment 2 of the present invention. Referring to FIG. 4, load drive device 100 </ b> A further includes current sensor 34 in the configuration of load drive device 100 in the first embodiment shown in FIG. 1, and includes control device 20 </ b> A instead of control device 20.

  Current sensor 34 detects current I2 input / output to / from battery B, and outputs the detected current I2 to control device 20A.

  When motor generator MG is driven, control device 20A, based on current I1 from current sensor 32 and current I2 from current sensor 34, uses a method to be described later, and includes pre-control resistor R and system main relay SMR1. The protection control for protecting the charge circuit is executed.

  Other operations in the control device 20A are the same as those in the control device 20 of the first embodiment. The other configuration of the load driving device 100A is the same as that of the load driving device 100 in the first embodiment.

  FIG. 5 is a flowchart of protection control by the control device 20A shown in FIG. Referring to FIG. 5, this processing flow further includes step S115 in the protection control processing flow by control device 20 in the first embodiment shown in FIG.

  That is, when it is determined in step S110 that current I1 from current sensor 32 is larger than a predetermined reference value Ith (NO in step S110), control device 20A determines that current I2 from current sensor 34 is a predetermined reference value. It is determined whether or not Ith is exceeded (step S115). When control device 20A determines that current I2 is equal to or smaller than predetermined reference value Ith (NO in step S115), the series of processing ends.

  On the other hand, when control device 20A determines that current I2 exceeds predetermined reference value Ith (YES in step S115), it determines that system main relay SMR2 has an open failure. Then, control device 20 outputs H level signal SDOWN to inverter 10 and stops inverter 10 (step S120).

  That is, when the current I1 exceeds the predetermined reference value Ith but the current I2 is equal to or less than the predetermined reference value Ith, the control device 20A determines that the current sensor 32 is abnormal, and Stop processing is not executed. In order to improve the reliability of the protection control, the inverter 10 is stopped only when a current exceeding a predetermined reference value Ith is detected in either of the current sensors 32 and 34. It is a thing.

  As described above, according to the second embodiment, the reliability of protection control is improved.

[Embodiment 3]
FIG. 6 is a schematic block diagram of a load driving device including a power supply device according to Embodiment 3 of the present invention. Referring to FIG. 6, load drive device 100 </ b> B includes voltage sensor 40 instead of current sensor 32 in the configuration of load drive device 100 in the first embodiment shown in FIG. 1, and replaces control device 20. A control device 20B is provided.

  The voltage sensor 40 detects the voltage VR across the limiting resistor R and outputs the detected voltage VR to the control device 20B. Based on voltage VR from voltage sensor 40 and the resistance value of limiting resistor R, control device 20B calculates current I1 flowing through the precharge circuit including limiting resistor R and system main relay SMR1. Then, control device 20B performs protection control for protecting the precharge circuit based on the calculated current I1. Note that the processing flow of this protection control is the same as the flowchart shown in FIG.

  Other operations in the control device 20B are the same as those in the control device 20 of the first embodiment. Other configurations of the load driving device 100B are the same as those of the load driving device 100 in the first embodiment.

  As described above, this third embodiment can provide the same effects as those of the first embodiment.

  Although not particularly illustrated, in the second embodiment, the voltage sensor 40 described above may be provided in place of the current sensor 32 to detect the current flowing in the precharge circuit.

  In the first to third embodiments, the precharge circuit including the limiting resistor R and the system main relay SMR1 is connected in parallel to the system main relay SMR2. However, the precharge circuit is parallel to the system main relay SMR3. May be connected.

  In the above, a boost converter may be provided between system main relays SMR1 to SMR3 and inverter 10. As this boost converter, a known boost converter including a chopper circuit can be used. Then, when abnormality of system main relay SMR2 is detected, inverter 10 may be stopped and the boost converter may be stopped.

  In the above description, the battery B is a secondary battery, but may be a fuel cell. The load driving devices 100, 100A, and 100B are mounted on a hybrid vehicle or an electric vehicle, but may be mounted on a fuel cell vehicle that uses a fuel cell as a DC power source.

  In the above, system main relay SMR1 corresponds to “precharge relay” in the present invention, and system main relays SMR2 and SMR3 correspond to “first relay” and “second relay” in the present invention, respectively. Correspond. Limiting resistor R corresponds to “resistive element” in the present invention, and current sensors 32 and 34 correspond to “first current detecting means” and “second current detecting means” in the present invention, respectively. Further, step S110 executed in control devices 20 and 20A and step S115 executed in control device 20A correspond to the processing executed by the “abnormality detection means” in the present invention and are executed in control devices 20 and 20A. Steps S120 and S130 correspond to processing executed by the “control means” in the present invention. Further, inverter 10 corresponds to “load driving circuit” in the present invention, and battery B corresponds to “DC power supply” in the present invention.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and is intended to include meanings equivalent to the scope of claims for patent and all modifications within the scope.

1 is a schematic block diagram of a load driving device including a power supply device according to Embodiment 1 of the present invention. It is a flowchart of the precharge process by the control apparatus shown in FIG. It is a flowchart of the protection control by the control apparatus shown in FIG. It is a schematic block diagram of the load drive device provided with the power supply device by Embodiment 2 of this invention. It is a flowchart of the protection control by the control apparatus shown in FIG. It is a schematic block diagram of the load drive device provided with the power supply device by Embodiment 3 of this invention.

Explanation of symbols

  10 inverter, 20, 20A, 20B control device, 30, 40 voltage sensor, 32, 34 current sensor, B battery, R limiting resistor, SMR1-SMR3 system main relay, Q transistor, D diode, PL power supply line, SL ground line , C capacitor, MG motor generator.

Claims (8)

A power supply device that exchanges power with a load drive circuit,
DC power supply,
A precharging relay provided between one pole of the DC power supply and the load driving circuit, including a transistor and a diode connected in parallel to the transistor;
A resistance element connected in series with the precharge relay between one pole of the DC power source and the load driving circuit;
A first relay provided between one pole of the DC power supply and the load driving circuit, and connected in parallel to the series-connected precharge relay and the resistance element;
A second relay provided between the other pole of the DC power supply and the load driving circuit;
First current detection means for detecting a current flowing through the series-connected precharge relay and the resistance element;
An abnormality detection means for detecting an abnormality of the power supply device based on the current detected by the first current detection means when the transistor is off;
A power supply apparatus comprising: control means for outputting a command to stop the load drive circuit to the load drive circuit when an abnormality is detected by the abnormality detection means.   The abnormality detection unit detects that an abnormality that causes the first relay to be in an open state occurs when a current larger than a predetermined reference value is detected by the first current detection unit. The power supply described. A second current detection means for detecting a current input to and output from the DC power supply;
The abnormality detection unit detects that an abnormality that causes the first relay to be opened occurs when a current larger than a predetermined reference value is detected by the first and second current detection units. Item 2. The power supply device according to Item 1.   4. The control device according to claim 1, wherein when the abnormality detection unit detects an abnormality, the control unit further outputs a command to instruct the opening of the second relay to the second relay. 5. The power supply device according to item. A control method of a power supply device that exchanges power with a load driving circuit,
The power supply device
DC power supply,
A precharging relay provided between one pole of the DC power supply and the load driving circuit, including a transistor and a diode connected in parallel to the transistor;
A resistance element connected in series with the precharge relay between one pole of the DC power source and the load driving circuit;
A first relay provided between one pole of the DC power supply and the load driving circuit, and connected in parallel to the series-connected precharge relay and the resistance element;
A second relay provided between the other pole of the DC power supply and the load driving circuit;
A first current detecting means for detecting a current flowing through the precharge relay and the resistance element connected in series;
The control method is:
A first step of detecting an abnormality of the power supply device based on a current detected by the first current detection means when the transistor is off;
And a second step of outputting a command to stop the load drive circuit to the load drive circuit when an abnormality is detected in the power supply device.   The said 1st step detects that abnormality which the said 1st relay will be in the open state generate | occur | produced when the electric current larger than a predetermined reference value is detected by the said 1st electric current detection means. The control method of the power supply device described in 1. The power supply device further includes second current detection means for detecting a current input to and output from the DC power supply,
In the first step of the control method, when a current larger than a predetermined reference value is detected by the first and second current detection means, an abnormality that causes the first relay to open is generated. The method for controlling the power supply device according to claim 5, wherein the detection is performed.   The control method further includes a third step of outputting an instruction to open the second relay to the second relay when an abnormality of the power supply device is detected in the first step. The method for controlling a power supply device according to any one of claims 5 to 7.

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