Power Supply System

Abstract

To provide a power supply system for detecting deposition of a power supply contactor for switching an output of a power supply circuit into a conduction state or a cutoff state even when the power supply circuit stops during power supply from a battery of an electric vehicle to the outside.SOLUTION: In a power supply system 10 in an electric vehicle, a control unit for controlling an OBC (a charging circuit) 16, an OBPS (a power feeding circuit) 18, a battery connector 20, a power feeding contactor 22, a power feeding switch, and a voltage sensor 36 includes a deposition detection unit that detects deposition of the power supply contactor 22 when power supply from a battery 14 to a load is finished, and detects deposition of the power supply contactor 22 after a lapse of a predetermined time from stop of operation of an OBPS18 when operation of the OBPS that is a power supply circuit is stopped.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a power supply system. [Background technology]

[0002] In recent years, research and development has been conducted into charging vehicles equipped with secondary batteries that contribute to energy efficiency, in order to ensure that more people have access to affordable, reliable, sustainable and advanced energy.

[0003] Patent Document 1 listed below discloses an electric vehicle that supplies power. In this electric vehicle, welding of a contactor provided between a secondary battery and a power charging port connected to an external load is detected. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2014-193082 A Summary of the Invention [Problem to be solved by the invention]

[0005] The technique disclosed in the above Patent Document 1 has a problem in that if the power supply circuit stops during power supply, welding of the contactor cannot be detected.

[0006] The present invention aims to solve the above-mentioned problems. [Means for solving the problem]

[0007] One aspect of the present invention is a power supply system for an electric vehicle, the power supply system including: a charging port to which a power source external to the electric vehicle or a load external to the electric vehicle is connected; a battery for storing power; a charging circuit provided between the charging port and the battery and supplying power from the power source to the battery; a power supply circuit provided between the charging port and the battery and supplying power from the battery to the load; an operation status acquisition unit for acquiring an operation status of the power supply circuit; a conductive state provided between the power supply circuit and the charging port and providing conductivity between the power supply circuit and the charging port; The battery pack includes a contactor that switches between a cut-off state in which the power supply circuit and the charging port are cut off, a welding detection unit that detects welding of the contactor and determines whether the contactor is welded, and a charging and power supply prohibition control unit that prohibits charging of the battery and supply of power to the load when it is determined that the contactor is welded, wherein when power supply from the battery to the load is terminated, the welding detection unit detects welding of the contactor, and when operation of the power supply circuit stops, the welding detection unit detects welding of the contactor a predetermined time after operation of the power supply circuit stops. Effect of the Invention

[0008] According to the present invention, even if the power supply circuit stops during power supply, welding of the contactor can be detected. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is a circuit diagram of a power supply system. [Diagram 2] FIG. 2 is a block diagram of the control device. [Diagram 3] FIG. 3 is a flowchart showing the power supply control process executed in the control device. [Figure 4] FIG. 4 is a flowchart showing the power supply control process executed in the control device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] [First embodiment] FIG 1 is a circuit diagram of a power supply system 10 according to the present embodiment. The power supply system 10 is mounted on an electric vehicle. An external power supply is connected to a charging port 12 of the electric vehicle. but The battery 14 is charged by the power supplied from the power source. but The load operates on the power supplied from the battery 14. The battery 14 is a secondary battery, specifically a lithium ion battery. The battery 14 is also used as a power source for the drive motor of the electric vehicle.

[0011] An on-board charger 16 (hereinafter, referred to as OBC 16) is provided between the charging port 12 and the battery 14. The OBC 16 includes an inverter, a transformer, and the like. The OBC 16 converts AC power supplied from a power source into DC power, boosts the voltage, and outputs the DC power to the battery 14. The OBC 16 corresponds to a charging circuit of the present invention.

[0012] An on-board power supply 18 (hereinafter, referred to as OBPS 18) is provided in parallel with the OBC 16. The OBPS 18 includes an inverter, an X capacitor, a smoothing capacitor, etc. The OBPS 18 converts DC power supplied from the battery 14 into AC power, reduces the voltage, and outputs the AC power to the charging port 12. The OBPS 18 corresponds to a power supply circuit of the present invention.

[0013] Alumni C 1 6 and the battery 14, and between the OBPS 18 and the battery 14. The battery contactor 20 switches between a conductive state in which current flows and a cut-off state in which the flow of current is cut off. The battery contactor 20 has a contactor 20a provided on the positive line and a contactor 20b provided on the negative line.

[0014] A power supply contactor 22 is provided between the OBPS 18 and the charging port 12. The power supply contactor 22 switches between a conductive state in which current flows and a cut-off state in which the flow of current is cut off. The power supply contactor 22 has a contactor 22a provided on the voltage line and a contactor 22b provided on the neutral line. The power supply contactor 22 corresponds to the contactor of the present invention.

[0015] The OBC 16 is used when the battery 14 is charged from an external power source, and the OBPS 18 is used when power is supplied from the battery 14 to an external load. When the battery 14 is being charged, power with a voltage of about 200V to 240V is input to the OBC 16. salary When power is applied, the OBPS 18 outputs a power of about 100V to 120V.

[0016] When power from an external power source is input to OBPS 18 during charging, a voltage exceeding the withstand voltage may be applied to the X capacitor of OBPS 18. Also, when power from an external power source is input to OBPS 18 during charging, an inrush current may flow into the smoothing capacitor of OBPS 18, causing a current exceeding the withstand current to flow through the IGBT (Insulated Gate Bipolar Transistor) of the inverter.

[0017] Therefore, during charging, the power supply system 10 disconnects the OBPS 18 from the charging port 12 by the power supply contactor 22.

[0018] The power supply system 10 includes a control device 24. Fig. 2 is a block diagram of the control device 24. The control device 24 includes an operation state acquisition unit 26, a power supply circuit control unit 28, a welding detection unit 30, and a charging / power supply inhibition control unit 32.

[0019] The operation state acquisition unit 26, the power supply circuit control unit 28, the welding detection unit 30, and the charging / power supply inhibition control unit 32 are realized by, for example, a processing circuit. The processing circuit is configured by, for example, an integrated circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array). The processing circuit may also be configured by an electronic circuit including discrete devices.

[0020] The processing circuit may be configured with a processor such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). In this case, the processing circuit is realized by the processor executing a program stored in a storage unit (not shown).

[0021] The operation state acquisition unit 26 acquires the inverter of the OBPS 18. of The smaller the duty ratio of the drive signal is, the greater the power output from the OBPS 18 is.

[0022] In the following cases (1) to (4), the duty ratio of the drive signal becomes 100%, and the OBPS 18 stops.

[0023] (1) When the voltage on the output side of OBPS18 is low (2) When the voltage on the output side of OBPS18 is overvoltage (3) When OBPS18 is at high temperature (4) If OBPS18 fails

[0024] The output side of OBPS18 refers to the side where OBPS18 is connected to charging port 12. Causes of a low voltage on the output side of OBPS18 include an overload in an external load and a short circuit in an external load. Causes of an overvoltage on the output side of OBPS18 include the application of a surge voltage from an external load. Causes of a high temperature on OBPS18 include continuous operation of OBPS18 in a high temperature environment. Causes of a failure of OBPS18 include an abnormality in the sensor in the inverter of OBPS18 and a short circuit in the AC wiring connected to OBPS18.

[0025] In the above cases (1) to (3), OBPS 18 returns to normal after a predetermined time has elapsed. After the return, the duty ratio of the drive signal in the inverter of OBPS 18 becomes less than 100%. In the above case of (4), OBPS 18 does not return to normal, and the duty ratio of the drive signal remains at 100%. In the above case of (4), a notification may be issued to encourage the user to take the vehicle to a dealer or the like for repairs.

[0026] When the power supply switch 34 is turned on, power supply to an external load is started. When the power supply switch 34 is turned off, power supply to the external load is stopped. The power supply switch 34 is operated by a user of the electric vehicle.

[0027] The power supply circuit control unit 28 controls the OBPS 18 and the power supply contactor 22 based on a signal from the power supply switch 34 .

[0028] The welding detection unit 30 detects welding of the power supply contactor 22. When the power supply switch 34 is turned off and power supply is terminated, the welding detection unit 30 detects welding. When the OBPS 18 stops during power supply, the welding detection unit 30 detects welding a predetermined time after the OBPS 18 stops.

[0029] When detecting a weld, the weld detection unit 30 controls the OBPS 18 via the power supply circuit control unit 28 to output power from the OBPS 18. The weld detection unit 30 also controls the power supply contactor 22 via the power supply circuit control unit 28 to turn on only one of the contactor 22a and the contactor 22b. In this state, the magnitude of the voltage detected by the voltage sensor 36 provided in the OBC 16 is but If the voltage is equal to or greater than the predetermined value, the welding detection unit 30 determines that the power supply contactor 22 is welded. The welding detection unit 30 controls the power supply contactor 22 to turn on only the other of the contactor 22a and the contactor 22b. In this state, the magnitude of the voltage detected by the voltage sensor 36 provided in the OBC 16 is but If the measured value is equal to or greater than the predetermined value, the welding detection unit 30 determines that the power supply contactor 22 is welded.

[0030] The charging and power supply inhibition control unit 32 inhibits charging of the battery 14 from an external power source and power supply from the battery 14 to an external load in the following cases. The following cases are when the welding detection unit 30 determines that the power supply contactor 22 is welded, or when the OBPS 18 does not return to normal even after a predetermined time has elapsed since it was stopped. In this case, the charging and power supply inhibition control unit 32 stops the OBC 16 and the OBPS 18. The charging and power supply inhibition control unit 32 also switches the battery contactor 20 and the power supply contactor 22 to an interrupted state.

[0031] 3 and 4 are flowcharts showing the process of power supply control executed by the control device 24. The power supply control is repeatedly executed at a predetermined cycle.

[0032] In step S1, the power supply circuit control unit 28 determines whether the charging / supply prohibition flag is "0" or "1." If the charging / supply prohibition flag is "0," the process proceeds to step S2. If the charging / supply prohibition flag is "1," the power supply control is terminated.

[0033] In step S2, the power supply circuit control unit 28 determines whether the power supply stop flag is "0" or "1." If the power supply stop flag is "0," the process proceeds to step S3. . salary electric stop If the stop flag is "1", the process proceeds to step S13.

[0034] In step S3, the power supply circuit control unit 28 determines whether the signal of the power supply switch 34 has switched from off to on. If the signal of the power supply switch 34 has switched from off to on, the process proceeds to step S4. If the signal of the power supply switch 34 has not switched from off to on, the process proceeds to step S5. If the signal of the power supply switch 34 was off when power supply control was executed in the previous cycle, and the signal of the power supply switch 34 is on when power supply control is executed in the current cycle, it can be determined that the signal of the power supply switch 34 has switched from off to on.

[0035] In step S4, the power supply circuit control unit 28 outputs an output command to the OBPS 18 and the power supply contactor 22. Thereafter, the power supply control ends. Based on the output command, the power supply contactor 22 becomes conductive. Based on the output command, the OBPS 18 operates.

[0036] In step S5, the power supply circuit control unit 28 determines whether the signal of the power supply switch 34 has switched from on to off. If the signal of the power supply switch 34 has switched from on to off, the process proceeds to step S9. If the signal of the power supply switch 34 has not switched from on to off, the process proceeds to step S6. If the signal of the power supply switch 34 was on when power supply control was executed in the previous cycle and the signal of the power supply switch 34 is off when power supply control is executed in the current cycle, it can be determined that the signal of the power supply switch 34 has switched from on to off.

[0037] In step S6, the power supply circuit control unit 28 determines whether the signal of the power supply switch 34 is on or off. If the signal of the power supply switch 34 is on, the process proceeds to step S7. If the signal of the power supply switch 34 is off, the power supply control is ended.

[0038] In step S7, the power supply circuit control unit 28 judges whether the duty ratio of the inverter drive signal in the OBPS 18 is 100% or less than 100%. If the duty ratio is 100%, the process proceeds to step S8. If the duty ratio is less than 100%, the power supply control ends. If the signal of the power supply switch 34 is on, the power supply circuit control unit 28 monitors the operation of the OBPS 18 in the power supply control in each cycle. If the duty ratio of the inverter drive signal is 100%, the power supply circuit control unit 28 judges that the OBPS 18 is stopped. If the duty ratio of the inverter drive signal is less than 100%, the power supply circuit control unit 28 can determine that the OBPS 18 is operating.

[0039] In step S8, the power supply circuit control unit 28 sets the power supply stop flag to "1." Then, the power supply control ends. The power supply stop flag being "1" indicates that the OBPS 18 is stopped.

[0040] When the power supply switch 34 is operated and the signal is switched from on to off, in step S9, the welding detection unit 30 performs welding detection for the power supply contactor 22. Then, the process proceeds to step S10.

[0041] In step S10, the welding detection unit 30 determines whether or not the power supply contactor 22 is welded. If the power supply contactor 22 is welded, the process proceeds to step S11. If the power supply contactor 22 is not welded, the process proceeds to step S12.

[0042] In step S11, the charging / supply prohibition control unit 32 sets the charging / supply prohibition flag to "1." Then, the process proceeds to step S12. For example, when the electric vehicle is brought to a dealer or the like and the power supply system 10 is repaired, the charging / supply prohibition flag is set to "0."

[0043] In step S12, the charge / power supply prohibition control unit 32 outputs a charge / power supply prohibition command. Then, the power supply control ends. Based on the charge / power supply prohibition command, the battery contactor 20 and the power supply contactor 22 are controlled to be in an interrupted state. Based on the charge / power supply prohibition command, the OBC 16 and the OBPS 18 are stopped.

[0044] If OBPS 18 is stopped, in step S13, power supply circuit control unit 28 calculates the elapsed time. The elapsed time indicates the time from when OBPS 18 is stopped to when the processing of step S13 is performed. Each time the processing of step S13 is performed, power supply circuit control unit 28 can calculate the elapsed time by adding the time of one cycle of power supply control to the elapsed time calculated in the previous cycle.

[0045] In step S14, the power supply circuit control unit 28 determines whether the elapsed time is equal to or greater than a predetermined time or less than a predetermined time. If the elapsed time is equal to or greater than the predetermined time, the process proceeds to step S15. If the elapsed time is less than the predetermined time, the power supply control is terminated.

[0046] If a predetermined time or more has elapsed since the OBPS 18 was stopped, in step S15, the welding detection unit 30 performs welding detection for the power supply contactor 22. Then, the process proceeds to step S16.

[0047] In step S16, the power supply circuit control unit 28 determines whether the duty ratio of the inverter drive signal in the OBPS 18 is 100% or less than 100%. If the duty ratio is 100%, 20 If the duty ratio is less than 100%, the process proceeds to step S17.

[0048] In step S17, the power supply circuit control unit 28 sets the power supply stop flag to “0.” Then, the process proceeds to step S18.

[0049] In step S18, the welding detection unit 30 determines whether or not the power supply contactor 22 is welded. If the power supply contactor 22 is welded, the process proceeds to step S20. If the power supply contactor 22 is not welded, the process proceeds to step S19.

[0050] In step S19, the power supply circuit control unit 28 outputs an output command to the OBPS 18 and the power supply contactor 22. Thereafter, the power supply control ends. Based on the output command, the power supply contactor 22 becomes conductive. Based on the output command, the OBPS 18 operates.

[0051] In step S20, the charging / power supply prohibition control unit 32 sets the charging / power supply prohibition flag to “1.” Then, the process proceeds to step S21.

[0052] In step S21, the power supply circuit control unit 28 outputs an output stop command. Then, the power supply control is terminated. Based on the output stop command, the power supply contactor 22 is controlled to an interrupted state. Based on the output stop command, the OBPS 18 is stopped.

[0053] [Effects] In the above cases (1) to (4), the OBPS 18 stops to protect the OBPS 18. While the OBPS 18 is stopped, it is not possible to detect welding of the power supply contactor 22. However, in the above cases (1) to (3), the OBPS 18 returns to operation after a predetermined time has elapsed.

[0054] Therefore, in the power supply system 10 of the present embodiment, the welding detection unit 30 performs welding detection a predetermined time after the OBPS 18 is stopped. This makes it possible to detect welding of the power supply contactor 22 even after the OBPS 18 is stopped. This also contributes to energy efficiency.

[0055] Furthermore, in the power supply system 10 of this embodiment, if the OBPS 18 does not recover even after a predetermined time has elapsed since the operation of the OBPS 18 stopped, the charge and supply inhibition control unit 32 inhibits charging of the battery 14 from an external power source and supply of power from the battery 14 to an external load. If the OBPS 18 does not recover, it is determined that the OBPS 18 has failed, and the charge and supply inhibition control unit 32 can inhibit charging of the battery 14 from an external power source and supply of power from the battery 14 to an external load.

[0056] The present invention is not limited to the above-described embodiment, and various configurations can be adopted without departing from the gist of the present invention.

[0057] [Invention Obtained from the Embodiments] The invention that can be understood from the above embodiment will be described below.

[0058] A power supply system (10) for an electric vehicle, the power supply system comprising: a charging port (12) to which a power source external to the electric vehicle or a load external to the electric vehicle is connected; a battery (14) for storing electric power; a charging circuit (16) provided between the charging port and the battery and for supplying electric power from the power source to the battery; a power supply circuit (18) provided between the charging port and the battery and for supplying electric power from the battery to the load; an operation status acquisition unit (26) for acquiring an operation status of the power supply circuit; and a conduction state acquisition unit (27) provided between the power supply circuit and the charging port for establishing conduction between the power supply circuit and the charging port. The battery charging device further includes a contactor (22) that switches between a disconnection state in which the power supply circuit and the charging port are disconnected and a disconnection state in which the power supply circuit and the charging port are disconnected, a welding detection unit (30) that detects welding of the contactor and determines whether the contactor is welded, and a charging and power supply prohibition control unit (32) that prohibits charging of the battery and power supply to the load when it is determined that the contactor is welded, where when power supply from the battery to the load is terminated, the welding detection unit detects welding of the contactor, and when operation of the power supply circuit is stopped, the welding detection unit detects welding of the contactor a predetermined time after operation of the power supply circuit is stopped. This makes it possible to detect welding of the contactor even after the power supply circuit is stopped.

[0059] In the above power supply system, if the power supply circuit does not recover after a predetermined time from when the operation of the power supply circuit stops, the charging and power supply prohibition control unit may prohibit charging of the battery and power supply to the load. In this way, if the power supply circuit does not recover, it is determined that the power supply circuit has failed, and charging and power supply can be prohibited. [Explanation of symbols]

[0060] 10...Power supply system 12...Charging port 14... Battery 16... OBC (charging circuit) 18...OBPS (power supply circuit) 22...Power supply contactor (contactor) 26: Operation status acquisition unit 30: Welding detection unit 32...Charging prohibition control unit

Claims

1. A power supply system for an electric vehicle, comprising: a charging port to which an external power source of the electric vehicle or an external load of the electric vehicle is connected; A battery for storing power; a charging circuit provided between the charging port and the battery, the charging circuit supplying power from the power source to the battery; a power supply circuit provided between the charging port and the battery, the power supply circuit supplying the power of the battery to the load; an operation state acquisition unit for acquiring an operation state of the power supply circuit; a contactor provided between the power supply circuit and the charging port, the contactor switching between a conductive state in which the power supply circuit and the charging port are conductive and a cut-off state in which the power supply circuit and the charging port are cut off; a welding detection unit that detects welding of the contactor and determines whether the contactor is welded; a charge / power supply inhibition control unit that inhibits charging of the battery and supply of power to the load when it is determined that the contactor is welded; having a power supply circuit configured to detect a state where a contactor is welded when a predetermined time required for protecting the power supply circuit has elapsed since the power supply circuit stops operating when the power supply circuit stops operating during power supply;

2. 2. The power supply system according to claim 1, When the power supply circuit does not return to normal operation after the predetermined time has elapsed since the operation of the power supply circuit stopped during power supply, the charging and power supply prohibition control unit prohibits charging of the battery and supply of power to the load.

Images