A fault diagnosis method of a power distribution switch of a charger, a vehicle, and a storage medium

Abstract

This invention provides a fault diagnosis method, vehicle, and storage medium for a charger's power distribution switch, including disconnecting the power distribution switch and an output switch; setting the charger's output voltage as a diagnostic signal voltage, which is less than the battery's undervoltage protection voltage; if the voltage at the first port equals the first output voltage, a short-circuit fault is determined in the power distribution switch; if the voltage at the first port equals 0, the power distribution switch is closed; if the voltage at the second port is not equal to the second output voltage, an open-circuit fault is determined in the power distribution switch; if the voltage at the second port equals the second output voltage, a charging step is executed. This invention utilizes the charger's inherent functional circuitry without adding any hardware to the power distribution switch fault diagnosis function; the required function is entirely implemented through software programs, reducing the complexity of the system hardware and without increasing hardware costs.

Description

Technical Field

[0001] This invention relates to the field of energy equipment, and more particularly to a method for diagnosing faults in the power distribution switch of a charger, a vehicle, and a storage medium. Background Technology

[0002] New energy vehicles are characterized by being environmentally friendly and less polluting because they do not burn gasoline or diesel fuel. With the vigorous promotion and application of new energy power generation such as hydropower, wind power, solar power and nuclear power, many new energy vehicles are gradually being promoted and applied, such as new energy electric cars, new energy electric buses, new energy electric trucks, new energy electric cleaning vehicles, new energy electric rail transit vehicles, new energy electric air vehicles and new energy electric shipping vehicles.

[0003] New energy vehicles are generally equipped with batteries, chargers, motor control devices, motors, and power generation devices. The power transistors in the motor control device receive the DC power output from the battery and invert it into AC power to output to the motor. The motor then outputs rotational driving force to drive the power generation devices such as wheels and propellers, thereby propelling the vehicle forward.

[0004] With the rapid development of the new energy field, electric vehicles and fuel hybrid vehicles are increasing, and chargers are being used extensively. Therefore, ensuring that chargers can output stably is crucial.

[0005] Because the output rectifier and filter circuit of the charger has unidirectional conductivity, a short circuit will be formed when the battery is connected in reverse. Since the short-circuit discharge current of the battery is very large, it may burn out the related components and PCB in the short-circuit circuit. Therefore, in charging applications where the charger and battery are not fixedly connected, a power distribution switch needs to be placed at the charger output for reverse connection protection. In addition, in applications where a single charger charges multiple sets of batteries in parallel, multiple power distribution switches need to be placed between the charger output and each set of batteries. These power distribution switches serve two purposes: firstly, to distribute power and control the power-on sequence of the batteries, which must be powered on in a certain sequence; otherwise, large circulating currents may be generated between the batteries due to the electromotive force difference, damaging the related components in the current loop; secondly, they also serve the aforementioned reverse connection protection function.

[0006] The proper functioning of the power distribution switch at the charger's output end directly impacts the safety and reliability of battery charging. When the power distribution switch experiences contact sticking, it loses its reverse connection protection function, and the power distribution sequence becomes uncontrollable during multi-channel charging. This can damage the charger and even the battery, and in severe cases, may cause a fire. Conversely, if an open circuit fails to close properly, charging cannot be completed. Therefore, it is essential to ensure that these power distribution switches are functioning correctly before allowing normal charging.

[0007] For the testing of power distribution switches, existing technologies generally require the addition of dedicated functional circuits to the hardware. Some also require continuous injection of detection signals, while others require the switch being tested to be equipped with an auxiliary switch that is mechanically linked to the main switch. All of these will increase the cost of the hardware and the complexity of the system. Furthermore, continuous injection of detection signals may also cause interference to the electrical equipment. Summary of the Invention

[0008] The first objective of this invention is to provide a method for diagnosing faults in the power distribution switch of a charger without requiring additional detection modules.

[0009] A second objective of the present invention is to provide a vehicle for performing the above-described fault diagnosis method.

[0010] A third objective of this invention is to provide a storage medium capable of performing the above-described fault diagnosis method.

[0011] To achieve the first objective of this invention, a fault diagnosis method for a charging output switch is provided. An output filter capacitor is installed between the positive and negative output terminals of the charger. An output voltage sampling module is connected between the positive output terminal and the first terminal of the power distribution switch. A port voltage sampling module is connected between the second terminal of the power distribution switch and the battery. The battery includes a fuse, an output switch, battery cells, and a battery management system. The power distribution switch is sequentially connected to the fuse, output switch, and battery cells. The fault diagnosis method includes: disconnecting the power distribution switch and the output switch; setting the charger's output voltage as a diagnostic signal voltage, which is less than the battery's undervoltage protection voltage; sampling the first output voltage using the output voltage sampling module and sampling the first port voltage using the port voltage sampling module; if the first port voltage equals the first output voltage, a short circuit fault is determined in the power distribution switch; if the first port voltage equals 0, the power distribution switch is closed; sampling the second output voltage using the output voltage sampling module and sampling the second port voltage using the port voltage sampling module; if the second port voltage is not equal to the second output voltage, an open circuit fault is determined in the power distribution switch; if the second port voltage equals the second output voltage, the charging step is executed.

[0012] A further proposed solution involves the following charging steps: disconnecting the power distribution switch and closing the output switch; sampling the third port voltage through the port voltage sampling module; setting the output voltage to the third port voltage; closing the power distribution switch after the output filter capacitor has been pre-charged; receiving the charging voltage and charging current values ​​output by the battery management system of the battery, setting the charger's output voltage to the charging voltage value, setting the charger's output current to the charging current value, and charging the battery.

[0013] A further proposed solution involves using two or more batteries connected in parallel. Each battery is sequentially connected to a power distribution switch and a port voltage sampling module. The charging process includes: disconnecting all power distribution switches and closing all output switches; sampling multiple third port voltages using the port voltage sampling module; setting the output voltage to the lowest value among the multiple third port voltages; closing the power distribution switch after the output filter capacitor has been pre-charged; receiving the charging voltage and charging current values ​​output by the battery management system of the battery corresponding to the lowest third port voltage; setting the charger's output voltage to the charging voltage value and the charger's output current to the charging current value; and charging the battery.

[0014] A further solution is to shut down the charger and disconnect the power distribution switch when a short circuit fault or an open circuit fault is detected in the power distribution switch.

[0015] To achieve the second objective of this invention, this invention provides a vehicle comprising a charger and a battery. An output filter capacitor is disposed between the positive and negative output terminals of the charger. An output voltage sampling module is connected between the positive output terminal and the first terminal of a power distribution switch. A port voltage sampling module is connected between the second terminal of the power distribution switch and the battery. The battery is provided with a fuse, an output switch, battery cells, and a battery management system. The power distribution switch is sequentially connected to the fuse, the output switch, and the battery cells. The charger implements the fault diagnosis method described above.

[0016] To achieve the third objective of this invention, this invention provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the steps of the fault diagnosis method described above.

[0017] The beneficial effect of this invention is that, on the original basic charging circuit, no new dedicated detection function module for the power distribution switch is added. The output of the charger is used as the diagnostic signal voltage for fault diagnosis, and the diagnostic signal voltage is lower than the undervoltage protection voltage value. Subsequently, the power distribution switch is opened and closed in sequence. By judging the output voltage and port voltage, the fault detection of short circuit or open circuit of the power distribution switch can be realized. This invention utilizes the inherent functional circuit of the charger without adding any hardware to the fault diagnosis function of the power distribution switch. The required function is implemented entirely through software program, reducing the complexity of the system hardware and without increasing hardware costs.

[0018] Furthermore, during the charging process, the fault diagnosis strategy fully considers the pre-charge requirements of the charger's output filter capacitor before charging. Firstly, the diagnostic signal voltage is set to be lower than the battery's undervoltage protection voltage. Secondly, before entering actual charging, the charger's output voltage is first set to the lowest value of the battery port voltage (VBatmin_ini). After the charger is powered on, the power switch is closed only when the output voltage equals VBatmin_ini. Then, the charger's output voltage and current are set to the values ​​required for actual charging, officially entering the charging state. This ensures a smooth, clear, and concise diagnostic process, accurate results, and fast diagnostic speed. After diagnosis, the system can seamlessly transition to charging. The entire process is safe and reliable, preventing damage to the protection switch or other components in the charging circuit. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the charging circuit in an embodiment of the fault diagnosis method of the present invention.

[0020] Figure 2 This is a flowchart of an embodiment of the fault diagnosis method of the present invention.

[0021] Figure 3 This is a flowchart of the charging step in an embodiment of the fault diagnosis method of the present invention.

[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments. Detailed Implementation

[0023] Reference Figure 1, in this case, a charger 1 is used to charge two groups of batteries in parallel. The charger 1 includes a main power unit 101 and a control microcontroller 102. An output filter capacitor 111 is provided between the positive output terminal and the negative output terminal of the main power unit 101 of the charger. The sampling terminal of the output voltage sampling module 112 is connected between the positive output terminal and the first ends of the power distribution switches 121 and 122. The feedback terminal of the output voltage sampling module 112 is connected to the control microcontroller 102. The sampling terminal of the port voltage sampling module 131 is connected between the second end of the power distribution switch 121 and the battery 2. The sampling terminal of the port voltage sampling module 132 is connected between the second end of the power distribution switch 122 and the battery 3. The sampling terminals of the port voltage sampling module 131 and the port voltage sampling module 132 are connected to the control microcontroller 102. The battery 2 is provided with a fuse 201, an output switch 202, battery cells 203 and a battery management system 204. The power distribution switch 121 is sequentially connected to the fuse 201, the output switch 202 and the battery cells 203. The battery 3 is provided with a fuse 301, an output switch 302, battery cells 303 and a battery management system 304. The power distribution switch 122 is sequentially connected to the fuse 301, the output switch 302 and the battery cells 303. In this embodiment, the output filter capacitor, the output voltage sampling module, the power distribution switches and the output voltage sampling module are integrated in the charger 1 and are part of the charger. Of course, the above devices and circuits can also be externally arranged outside the charger. The power distribution switch may be an electrical switch such as a relay or a contactor, or an electronic switch such as a MOSFET or a thyristor.

[0024] Refer to Figure 2 , after the charger is connected to the alternating current and the battery, a fault diagnosis method is started, which includes the following steps. First, step S11 is executed to disconnect all the power distribution switches and all the output switches, that is, disconnect the power distribution switches 121 and 122 and the output switches 202 and 302. Subsequently, step S12 is executed. The output voltage Vset of the charger is set to the diagnostic signal voltage Vkfd, and the diagnostic signal voltage is less than the undervoltage protection voltage value Vbat_uvp of the battery, that is, Vkfd < Vbat_uvp. When the battery port voltage Vbat < Vbat_uvp, the charger will enter the undervoltage protection of the battery and turn off the output. The output current Iset of the charger is set to Ikfd, and Ikfd is the current limiting value for power distribution switch fault diagnosis. Subsequently, the charger is powered on.

[0025] Then, step S13 is executed, sampling the first output voltage Vout through output voltage sampling module 112, sampling the first port voltage VBat1 through port voltage sampling module 131, and sampling the first port voltage VBat2 through port voltage sampling module 132. Next, step S14 is executed. If Vout = VBat1, a short circuit fault is determined to have occurred in distribution switch 121; if Vout = VBat2, a short circuit fault is determined to have occurred in distribution switch 122. Then, step S15 is executed, charger 1 is shut down, and a short circuit warning is issued for the protection switch, disconnecting distribution switch 121 or 122. Then, step S16 is executed, and the charger enters a fault state. It should be noted that a short circuit fault in the distribution switch can also be determined when Vout is approximately equal to or near equal to VBat1, or approximately equal to or near equal to VBat2.

[0026] If the first port voltage VBat1 is equal to 0 and the second port voltage VBat2 is equal to 0, then step S21 is executed to close all power distribution switches, that is, to close power distribution switch 121 and power distribution switch 122. Then step S22 is executed to sample the second output voltage Vout again through the output voltage sampling module 112, sample the second port voltage VBat1 through the port voltage sampling module 131, and sample the second port voltage VBat2 through the port voltage sampling module 132.

[0027] Then, step S23 is executed. If the second output voltage Vout is not equal to the second port voltage VBat1, it is determined that the power distribution switch 121 has an open circuit fault. If the second output voltage Vout is not equal to the second port voltage VBat2, it is determined that the power distribution switch 122 has an open circuit fault. Then, step S24 is executed. The charger 1 is turned off and a protection switch open circuit warning is issued. The power distribution switch 121 or 122 is disconnected. Then, step S16 is executed and the charger enters the fault state.

[0028] If Vout = VBat1 and Vout = VBat2, then proceed to charging step S3. (Refer to...) Figure 3First, step S31 is executed: all power distribution switches are disconnected, and all output switches are closed. Specifically, power distribution switches 121 and 122 are disconnected, and output switches 202 and 302 are closed. Then, step S32 is executed: the third port voltage VBat1_ini is sampled through port voltage sampling module 131, and the third port voltage Vbat2_ini is sampled through port voltage sampling module 132. VBat_ini is the initial port voltage before battery charging. Then, step S33 is executed: multiple third port voltages are compared and the lowest value is selected. Specifically, VBat1_ini and Vbat2_ini are compared. Assuming VBat1_ini is the smallest, VBatmin_ini is set to Vbat1_ini. Then, step S34 is executed: the output voltage is... The charger's output voltage is set to the lowest among multiple third-port voltages, i.e., Vset is set to VBatmin_ini, while Iset remains unchanged. After the output filter capacitor is pre-charged (i.e., the voltage of the output filter capacitor reaches VBatmin_ini), step S35 is executed, closing the distribution switch Vbat = Vbatmin_ini. In this embodiment, distribution switch 121 is closed. After the distribution switch detection ends, the charger receives the charging voltage and charging current values ​​output by the battery management system 204 of battery 2 corresponding to the lowest third-port voltage Vbatmin_ini, and sets the charger's output voltage to the charging voltage value Vset and the charger's output current to the charging current value Iset, charging batteries 2 and 3. When the battery management system of each battery detects that it is fully charged, the battery management system sends a charging termination request to the charger. The charger disconnects the distribution switch corresponding to the fully charged battery. When all batteries are fully charged, the charger stops power output.

[0029] Regarding the pre-charging of the output filter capacitor, it should be noted that if the voltage on the output filter capacitor 111 is greater than the port voltage Vbat1_ini of the battery 1 before charging, an inrush current will be generated from the output filter capacitor 111 to the battery 1. If the voltage on the output filter capacitor 111 is less than the port voltage Vbat1 of the battery 1, an inrush current will be generated from the battery 1 to the output filter capacitor 111. If the inrush current is too large, it may damage the output switch of the charger, the battery fuse, and the output switch. Therefore, this should be avoided.

[0030] The vehicle includes a charger and a battery. An output filter capacitor is installed between the positive and negative output terminals of the charger. An output voltage sampling module is connected between the positive output terminal and the first terminal of the power distribution switch, and a port voltage sampling module is connected between the second terminal of the power distribution switch and the battery. The battery is equipped with an output switch. The charger implements the fault diagnosis method described above. The vehicle can be a new energy electric car, a new energy electric bus, a new energy electric freight truck, a new energy electric cleaning vehicle, a new energy electric rail transit vehicle, a new energy electric air transport vehicle, or a new energy electric shipping vehicle, etc.

[0031] A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the fault diagnosis method as described above.

[0032] As can be seen from the above, without adding a dedicated detection module for the power distribution switch to the original basic charging circuit, the output of the charger is used as the diagnostic signal voltage for fault diagnosis. The diagnostic signal voltage is lower than the undervoltage protection voltage value. Then, the power distribution switch is opened and closed in sequence. By judging the output voltage and port voltage, the fault detection of short circuit or open circuit of the power distribution switch can be realized. This case utilizes the inherent functional circuit of the charger without adding any hardware for the fault diagnosis function of the power distribution switch. The required function is implemented entirely through software program, reducing the complexity of the system hardware and without increasing hardware costs.

Claims

1. A failure diagnosis method of a distribution switch of a charger characterized by comprising: An output filter capacitor is provided between the positive and negative output terminals of the charger. An output voltage sampling module is connected between the positive output terminal and the first terminal of the power distribution switch. A port voltage sampling module is connected between the second terminal of the power distribution switch and the battery. The battery is provided with a fuse, an output switch, a battery cell, and a battery management system. The power distribution switch is connected in sequence to the fuse, the output switch, and the battery cell. The fault diagnosis method includes: Disconnect the power distribution switch and the output switch; The output voltage of the charger is set to a diagnostic signal voltage, which is less than the undervoltage protection voltage of the battery. The first output voltage is sampled by the output voltage sampling module, and the first port voltage is sampled by the port voltage sampling module; If the voltage at the first port is equal to the voltage at the first output port, then the power distribution switch is determined to have a short circuit fault. If the voltage at the first port is equal to 0, then close the power distribution switch; The second output voltage is sampled by the output voltage sampling module, and the second port voltage is sampled by the port voltage sampling module; If the voltage at the second port is not equal to the voltage at the second output port, then the power distribution switch is determined to have an open circuit fault. If the voltage at the second port is equal to the voltage at the second output port, then the charging step is performed.

2. The fault diagnosis method according to claim 1, characterized in that: The charging steps include: Disconnect the power distribution switch and close the output switch; The voltage of the third port is sampled using the port voltage sampling module. Set the output voltage to the third port voltage, and after the output filter capacitor has been pre-charged, close the power distribution switch; The charger receives the charging voltage and charging current values ​​output by the battery management system of the battery, sets the output voltage of the charger to the charging voltage value, sets the output current of the charger to the charging current value, and charges the battery.

3. The fault diagnosis method according to claim 1, characterized in that: The number of batteries is two or more, and multiple batteries are connected in parallel. Each battery and the output voltage sampling module are sequentially connected to a power distribution switch and a port voltage sampling module. The charging steps include: Disconnect all the aforementioned power distribution switches and close all the aforementioned output switches; The port voltage sampling module samples multiple third port voltages. Set the output voltage to the lowest value among the multiple third port voltages, and close the power distribution switch after the output filter capacitor has been pre-charged; The charger receives the charging voltage and charging current values ​​output by the battery management system of the battery corresponding to the lowest third port voltage, sets the output voltage of the charger to the charging voltage value, sets the output current of the charger to the charging current value, and charges the battery.

4. The fault diagnosis method according to any one of claims 1 to 3, characterized in that: When a short circuit fault or an open circuit fault is detected in the power distribution switch, the charging unit is turned off and the power distribution switch is disconnected.

5. Vehicle, characterized in that The device includes a charger and a battery. An output filter capacitor is provided between the positive and negative output terminals of the charger. An output voltage sampling module is connected between the positive output terminal and the first terminal of the power distribution switch. A port voltage sampling module is connected between the second terminal of the power distribution switch and the battery. The battery is equipped with a fuse, an output switch, battery cells, and a battery management system. The power distribution switch is connected in sequence to the fuse, the output switch, and the battery cells. The charger performs the fault diagnosis method according to any one of claims 1 to 4.

6. A computer readable storage medium having stored thereon a computer program, characterized in that: When the computer program is executed by the processor, it implements the steps of the fault diagnosis method as described in any one of claims 1 to 4.

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