Fuel cell system all-in-one controller and application method thereof

Abstract

The invention discloses a fuel cell system all-in-one controller and an application method thereof. Belongs to the fuel cell field. The first input end of the all-in-one controller is externally connected with a fuel cell stack, and internally connected to the output end of the all-in-one controller through an input EMI, a residual hydrogen discharge unit, an input capacitor, a DC / DC converter, an output capacitor, a PDU, an output relay unit, a protection unit and an output EMI in sequence; the output end is externally connected to a whole vehicle power battery; the second input end of the all-in-one controller is externally connected with the low-voltage storage battery and internally connected to the two ends of the input capacitor in parallel; a control system of the all-in-one controller is connected with the DC / DC converter and communicates with a fuel cell system controller; the output relay unit includes main positive and negative relays. According to the invention, the function safety and the product power density of the DC / DC are improved, the system cost is reduced, and effective identification of the adhesion relay is realized.

Description

Technical Field

[0001] The present invention belongs to the field of fuel cells, and in particular, relates to an all-in-one controller for a fuel cell system and an application method thereof. Background Art

[0002] As an intermediate carrier connecting the fuel cell stack and the external load of the system, the fuel cell DC / DC converter (DCF) plays the role of power distribution, voltage conversion, high-voltage pre-charging, etc., accounting for about 5-10% of the material cost of the entire system; it has a great impact on the efficiency, safety, reliability and other indicators of the fuel cell system. According to the number of single cells in the fuel cell stack and the voltage platform of the vehicle power battery, the fuel cell DC / DC converters currently used in the market can be divided into three topologies: boost, boost+buck, and buck, among which the boost solution is more widely used. Before the fuel cell system is started, the fuel cell stack cannot work because there is no fuel supply; the power battery is required to first power the system BOP components (such as hydrogen pumps, water pumps, and PTC); and there is only line resistance in the high-voltage bus circuit, and the resistance is very small. Due to the physical characteristics of the instantaneous short circuit of the capacitor after power is turned on and the large voltage difference between the two ends of the relay; at the moment the relay is closed, the impact current in the circuit will be very large, which is easy to cause the relay contacts to burn and stick. To protect the relay, the internal circuit of the DC / DC converter needs to be equipped with a pre-charging resistor and a pre-charging relay to form a pre-charging circuit to limit the current in the high-voltage circuit. Figure 4 As shown in the figure, when the voltage across the capacitor reaches 90% to 95% of the voltage at the load end, the main relay is closed to complete the pre-charging process. The high-voltage pre-charging solution can prevent the relay in the high-voltage circuit from being impacted by large current, effectively ensuring the service life of the relay.

[0003] However, the existing high-voltage pre-charging solutions also have shortcomings. On the one hand: if high-voltage pre-charging is to be achieved, another relay (such as the negative pole relay) must be closed first, and then the pre-charging circuit must be closed to achieve the pre-charging function; if the positive main relay is already adhered at this time, then after the negative pole relay is closed, a surge current will be generated in the circuit, causing the originally functional negative pole relay contacts to burn and adhere. On the other hand: considering safety, since the relay cannot be disconnected under load, the traditional high-voltage pre-charging solution can only be pre-charged until the voltages at both ends of the relay are consistent and then stop, and cannot be used for adhesion detection; nor can it make specific positioning of the adhesion relay. Finally, since the power demand of the fuel cell DC / DC converter is large, but the market size is small; it is impossible to achieve effective cost reduction of component prices, which is not conducive to product promotion, and there is still room for optimization in the topology architecture. Summary of the invention

[0004] The present invention aims to overcome the shortcomings of the prior art and proposes an all-in-one controller for a fuel cell system and an application method thereof, so as to achieve the following objectives: improve the functional safety and product power density of DC / DC and reduce system costs; at the same time, identify the problem that the traditional high-voltage pre-charging solution cannot accurately locate the sticking relay, which can effectively reduce the troubleshooting time.

[0005] In order to achieve the above object, the technical solution adopted by the present invention is:

[0006] A fuel cell system all-in-one controller, the all-in-one controller comprises a first input terminal, a second input terminal, an input EMI, a residual hydrogen discharge unit, an input capacitor, a DC / DC converter, a control system, an output capacitor, a PDU, an output relay unit, a protection unit, an output EMI, and an output terminal; wherein the first input terminal is externally connected to a fuel cell stack, and is internally connected to the output terminal through the input EMI, the residual hydrogen discharge unit, the input capacitor, the DC / DC converter, the output capacitor, the PDU, the output relay unit, the protection unit, and the output EMI in sequence; the output terminal is externally connected to a vehicle power battery; the second input terminal is externally connected to a low-voltage battery, and is internally connected in parallel to both ends of the input capacitor; the control system is connected to the DC / DC converter and also communicates with the fuel cell system controller; the output relay unit comprises a main positive and a main negative relay, wherein the main positive relay is connected in series to the positive line between the PDU and the protection unit; the main negative relay is connected in series to the negative line between the PDU and the protection unit.

[0007] Preferably, a current sensor A1 is connected in series on the high-voltage bus between the input EMI and the residual hydrogen discharge unit; a voltage sensor V1 is connected in parallel at both ends of the residual hydrogen discharge unit; a current sensor A2 is connected in series on the high-voltage bus between the input capacitor and the DC / DC converter; a current sensor A3 is connected in series on the high-voltage bus between the output capacitor and the PDU; a voltage sensor V2 is connected in parallel between the PDU and the output capacitor; a voltage sensor V3 is connected in parallel at the input end of the low-voltage pre-charging unit; a voltage sensor V4 is connected in parallel at the output end of the low-voltage pre-charging unit; and a voltage sensor V5 is connected in parallel at both ends of the battery.

[0008] Preferably, the residual hydrogen discharge unit comprises a normally open relay and a discharge resistor, wherein the normally open relay and the discharge resistor are connected in series and connected in parallel to the output end of the input EMI.

[0009] Preferably, the all-in-one controller also includes an ACP controller, the input end of the ACP controller is connected to the PDU via EMI, and the output end of the ACP controller is connected to the air compressor.

[0010] Preferably, a diode is connected in series on the high-voltage bus between the second input terminal and the input capacitor, wherein the anode of the diode is connected to the second input terminal, and the cathode of the diode is connected to one end of the input capacitor.

[0011] Preferably, the all-in-one controller further comprises an AC impedance detection device EIS, and the EIS is connected to the control system.

[0012] Preferably, the DC / DC converter adopts a BOOST boost circuit.

[0013] Preferably, the protection unit comprises an output fuse, and the output fuse is connected in series on a high-voltage bus between the output relay unit and the output EMI.

[0014] At the same time, the present application proposes an application method of an all-in-one controller for a fuel cell system, the method being applied to power-on timing control of the all-in-one controller for the fuel cell system, comprising:

[0015] The all-in-one controller connects the low-voltage power T30 and feeds back the low-voltage power-on status to the fuel cell system controller;

[0016] The fuel cell system controller sends hardware enable to the all-in-one controller;

[0017] The all-in-one controller starts CAN communication and starts self-test; when the all-in-one controller passes the self-test, the self-test pass status is fed back to the fuel cell system controller;

[0018] The fuel cell system controller sends instructions to the all-in-one controller, the instructions including battery voltage detection, power battery voltage detection, and DC / DC low-voltage pre-charging instructions;

[0019] The all-in-one controller executes the instructions in sequence, detects the battery voltage and the power battery voltage through sensors, and determines whether they are within a preset voltage range;

[0020] If it is within the preset voltage range, it is considered that the fuel cell system meets the low-voltage pre-charging conditions. At this time, the all-in-one controller starts to perform low-voltage pre-charging: the all-in-one controller extracts electric energy from the low-voltage battery and feeds it back to the high-voltage bus at the front end of the input capacitor. Then the control system outputs a PWM signal to control the DC / DC controller to step up the voltage across the input capacitor and charge the output capacitor. When the voltage of the output capacitor is pre-charged to a preset ratio of the vehicle power battery voltage, the main positive relay and the main negative relay are closed in turn, and then the high-voltage relay adhesion detection is performed.

[0021] After the high-voltage relay adhesion detection is completed, the all-in-one controller uploads the pre-charge status of the DC / DC high-voltage side to the fuel cell system controller;

[0022] When the fuel cell system controller detects that the high-pressure side pre-charging is successful, it sends the ACP speed command value and control mode request to the all-in-one controller;

[0023] Correspondingly, the all-in-one controller drives the air compressor to operate and feeds back the speed data and the fuel cell stack voltage data to the fuel cell system controller;

[0024] The fuel cell system controller sends a constant current instruction, a constant current limit, and a constant current mode request to the all-in-one controller;

[0025] The all-in-one controller performs a constant current load mode on the fuel cell stack according to the constant current instruction, the constant current limit, and the constant current mode, and controls the fuel cell system to output stably.

[0026] The present application also proposes an application method of an all-in-one controller for a fuel cell system, the method being applied to relay sticking detection of the all-in-one controller for the fuel cell system, comprising:

[0027] The all-in-one controller first performs a self-test and then proceeds to the next step after passing the self-test;

[0028] When the all-in-one controller detects the low-voltage battery voltage and determines whether the battery voltage is within the preset battery voltage range, if so, it is considered that the battery voltage is normal and proceeds to the next step;

[0029] When the all-in-one controller detects the power battery voltage of the vehicle and determines whether the power battery voltage is within the preset power battery voltage range, if so, it is considered that the power battery voltage is normal and proceeds to the next step;

[0030] Execute the low-voltage pre-charge instruction and determine whether the voltage pre-charged to the output capacitor reaches a preset ratio of the power battery voltage. If so, proceed to the next step;

[0031] The all-in-one controller sends an instruction to close the main negative relay and determine whether there is current across the output capacitor; if so, it means that the main positive relay is stuck. At this time, the all-in-one controller reports a fault, returns to the self-test process, and waits for the system to process; if not, the all-in-one controller sends an instruction to disconnect the main negative relay, close the main positive relay, and determine whether there is current across the output capacitor at this time. If so, it means that the main negative relay is stuck. At this time, the all-in-one controller reports a fault, returns to the self-test process, and waits for the system to process; if not, it means that both the main positive relay and the main negative relay are not stuck. The all-in-one controller sends an instruction to close the main negative relay and end the sticking detection.

[0032] The technical effects of the present invention are:

[0033] (1) The system can complete pre-charging without a high-voltage pre-charging circuit; effectively reduce the system cost of the DC / DC converter; and improve the reliability of components.

[0034] (2) The present invention expands and integrates DC / DC to form an all-in-one controller including DC / DC, ACP, PDU, ESI, etc., thereby improving the power density of the product.

[0035] (3) By optimizing the existing topology, the voltage, current range and rising rate of the output end can be controlled; the bus voltage can be pre-charged to any voltage and then stopped.

[0036] (4) Combined with the relay sticking detection logic proposed in the present invention, the stuck relay can be specifically located, effectively reducing the troubleshooting time.

[0037] (5) The present invention is highly practical and can provide a new solution for the engineering development of fuel cell DC / DC converter manufacturers, and has a certain market application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 A schematic diagram of the structure of an all-in-one controller for a fuel cell system according to an embodiment of the present invention;

[0039] Figure 2 A power-on control timing diagram of an all-in-one controller of a fuel cell system according to an embodiment of the present invention;

[0040] Figure 3 A flow chart of a relay sticking detection method of an all-in-one controller of a fuel cell system according to an embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of a traditional high-voltage pre-charging circuit. DETAILED DESCRIPTION

[0042] The following is a further detailed description of the specific implementation of the present invention through the description of the embodiments with reference to the accompanying drawings, the purpose of which is to help those skilled in the art have a more complete, accurate and in-depth understanding of the inventive concept and technical solution of the present invention, and to facilitate its implementation. It should be noted that the words "first", "second" and the like described in this application are only for the convenience of describing the technical solution to distinguish different components, and are not used to limit this application. In order to make the technical solution of the present invention clearer, the present invention is explained through the following embodiments.

[0043] An all-in-one controller for a fuel cell system, such as Figure 1As shown, the all-in-one controller includes a first input terminal, a second input terminal, an input EMI (filter device), a residual hydrogen discharge unit, an input capacitor, a DC / DC converter, a control system, an output capacitor, a PDU (high-voltage distribution box), an output relay unit, a protection unit, an output EMI, and an output terminal.

[0044] Among them, the first input terminal is externally connected to the fuel cell stack, and is internally connected to the output terminal through the input EMI, residual hydrogen discharge unit, input capacitor, DC / DC converter, output capacitor, PDU, output relay unit, protection unit, and output EMI in sequence; the output terminal is externally connected to the vehicle power battery; the second input terminal is externally connected to a low-voltage battery (24V in this embodiment), and is internally connected in parallel to the two ends of the input capacitor; the control system is connected to the DC / DC converter and also communicates with the fuel cell system controller; the output relay unit includes a main positive relay K4 and a main negative relay K5, wherein the main positive relay is connected in series to the positive line between the PDU and the protection unit; the main negative relay is connected in series to the negative line between the PDU and the protection unit. Preferably, the DC / DC converter of this embodiment adopts a BOOST boost circuit. The PDU supports connection with external high-voltage devices such as high-pressure water pumps, high-pressure hydrogen pumps, heaters (PTC), and direct current reactors (DCL).

[0045] The all-in-one controller of this embodiment also includes an ACP (air compressor) controller, the input end of the ACP controller is connected to the PDU via EMI, and the output end of the ACP controller is connected to the air compressor.

[0046] The all-in-one controller of this embodiment further includes an AC impedance detection device EIS, and the EIS is connected to the control system.

[0047] In this embodiment, not only the basic functions of the DC / DC converter are retained, but also functions such as PDU, ACP, and AC impedance detection are integrated to form an all-in-one controller, which realizes function expansion and integration and improves product power density.

[0048] Specifically, in order to more intuitively realize the detection of the voltage and current state of the internal circuit of the all-in-one controller, in this embodiment, a current sensor A1 is connected in series on the high-voltage bus between the input EMI and the residual hydrogen discharge unit; a voltage sensor V1 is connected in parallel at both ends of the residual hydrogen discharge unit; a current sensor A2 is connected in series on the high-voltage bus between the input capacitor and the DC / DC converter; a current sensor A3 is connected in series on the high-voltage bus between the output capacitor and the PDU, which is used to detect the output current of the output capacitor; a voltage sensor V2 is connected in parallel between the PDU and the output capacitor; a voltage sensor V3 is connected in parallel to the input end of the low-voltage pre-charging unit, which is used to detect the pre-charging voltage of the output capacitor; a voltage sensor V4 is connected in parallel to the output end of the low-voltage pre-charging unit, which is used to detect the power battery voltage; a voltage sensor V5 is connected in parallel to both ends of the battery, which is used to detect the output voltage at both ends of the battery.

[0049] The residual hydrogen discharge unit of this embodiment includes a normally open relay and a discharge resistor, wherein the normally open relay and the discharge resistor are connected in series and connected in parallel to the output end of the input EMI. When the fuel cell system is turned on, the normally open relay is in a normally open state, and the current output by the fuel cell stack is only conducted in the high-voltage bus inside the all-in-one controller, and does not pass through the residual hydrogen discharge unit. When the fuel cell system is shut down, the normally open relay remains normally closed, and the residual hydrogen discharge unit discharges the residual hydrogen in the fuel cell stack.

[0050] In this embodiment, a diode is connected in series to the high-voltage bus between the second input terminal of the all-in-one controller and the input capacitor, wherein the positive electrode of the diode is connected to the second input terminal, and the negative electrode of the diode is connected to one end of the input capacitor. The physical properties of the diode, which is unidirectional conduction and reverse cutoff, are used to ensure that the battery current flows in one direction, so as to prevent the output energy from damaging the battery after the fuel cell stack is started.

[0051] The protection unit of this embodiment includes an output fuse, which is connected in series to the high-voltage bus between the output relay unit and the output EMI to protect the circuit and avoid damage to the power battery.

[0052] At the same time, this embodiment proposes an application method of an all-in-one controller for a fuel cell system, such as Figure 2 As shown, the method is applied to the power-on timing control of the all-in-one controller of the fuel cell system, including:

[0053] The all-in-one controller connects the low-voltage power T30 and feeds back the low-voltage power-on status to the fuel cell system controller;

[0054] The fuel cell system controller sends hardware enable (KL15 signal) to the all-in-one controller;

[0055] The all-in-one controller starts CAN communication and starts self-test. When the all-in-one controller passes the self-test, it feeds back the self-test pass status to the fuel cell system controller. The self-test includes system initialization, software and hardware interface configuration check, and sensor automatic calibration.

[0056] The fuel cell system controller sends instructions to the all-in-one controller, the instructions including battery voltage detection, power battery voltage detection, and DC / DC low-voltage pre-charging instructions;

[0057] The all-in-one controller executes the instructions in sequence, detects the battery voltage (read by the voltage sensor V5) and the power battery voltage (read by the voltage sensor V4) through the sensor, and determines whether they are within the preset voltage range; in this embodiment, the voltage range of the battery voltage is set between 21.6V and 30V, and the voltage range of the power battery is set between 450V and 750V;

[0058] If it is within the preset voltage range, it is considered that the fuel cell system meets the low-voltage pre-charging conditions. At this time, the all-in-one controller starts to perform low-voltage pre-charging: the all-in-one controller extracts electric energy from the low-voltage battery and feeds it back to the high-voltage bus at the front end of the input capacitor. Then the control system outputs a PWM signal to control the DC / DC controller to step up the voltage across the input capacitor and charge the output capacitor. The voltage, current range and rising rate of the output end of the DC / DC controller can be controlled, and the voltage of the output capacitor can be pre-charged to any voltage and then stopped. When the voltage of the output capacitor (read by the voltage sensor V3) is pre-charged to a preset proportion of the vehicle power battery voltage (95% in this embodiment, which can be flexibly selected according to actual conditions), the main positive relay and the main negative relay are closed in turn, and then the high-voltage relay adhesion detection is performed;

[0059] After the high-voltage relay adhesion detection is completed, the all-in-one controller uploads the pre-charge status (successful or failed) of the DC / DC high-voltage side to the fuel cell system controller;

[0060] When the fuel cell system controller detects that the high-pressure side pre-charging is successful, it sends the ACP speed command value and control mode request to the all-in-one controller;

[0061] Correspondingly, the all-in-one controller drives the air compressor to operate and feeds back the speed data and the fuel cell stack voltage data to the fuel cell system controller;

[0062] The fuel cell system controller sends a constant current instruction, a constant current limit, and a constant current mode request to the all-in-one controller;

[0063] The all-in-one controller performs a constant current load mode on the fuel cell stack according to the constant current instruction, the constant current limit, and the constant current mode, and controls the fuel cell system to output stably.

[0064] Furthermore, this embodiment also proposes an application method of an all-in-one controller for a fuel cell system, such as Figure 3 As shown, the method is applied to relay sticking detection of the fuel cell system all-in-one controller, including:

[0065] The all-in-one controller first performs a self-test and then proceeds to the next step after passing the self-test;

[0066] When the all-in-one controller detects the low-voltage battery voltage and determines whether the battery voltage is within a preset battery voltage range, if so, the battery voltage is considered normal and the next step is continued; in this embodiment, the battery voltage range is set to between 21.6V and 30V;

[0067] When the all-in-one controller detects the power battery voltage of the vehicle and determines whether the power battery voltage is within the preset power battery voltage range, if so, it is considered that the power battery voltage is normal and the next step is executed; in this embodiment, the power battery voltage range is set between 450V and 750V;

[0068] Execute the low-voltage pre-charge instruction and determine whether the voltage pre-charged to the output capacitor reaches or exceeds a preset ratio (95% in this embodiment) of the power battery voltage. If so, proceed to the next step;

[0069] The all-in-one controller sends an instruction to close the main negative relay and determine whether there is current across the output capacitor (which can be read by current sensor A3); if so, it means that the main positive relay is stuck. At this time, the all-in-one controller reports a fault, returns to the self-test process, and waits for the system to process; if not, the all-in-one controller sends an instruction to disconnect the main negative relay, close the main positive relay, and determine whether there is current across the output capacitor. If so, it means that the main negative relay is stuck. At this time, the all-in-one controller reports a fault, returns to the self-test process, and waits for the system to process; if not, it means that both the main positive relay and the main negative relay are not stuck. The all-in-one controller sends an instruction to close the main negative relay and end the sticking detection.

[0070] Through the inventive application of the present invention, the technical solution of the existing fuel cell DC / DC converter is optimized, the circuit topology is simplified, and the system integration is improved; the output capacitor on the high-voltage bus is pre-charged by a low-voltage pre-charging method, and the pre-charging can be stopped at any voltage. The present invention is combined with the relay adhesion detection and judgment method to effectively identify the specific location of the adhesion relay. The scheme of the present invention not only has a reliable working principle, but also helps to reduce the overall cost of the fuel cell DC / DC converter, and can provide a new idea for the design of high-voltage electrical equipment in fuel cell systems.

[0071] The present invention is described above by way of example in conjunction with the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-mentioned methods. As long as various non-substantial improvements are made using the method concept and technical solution of the present invention; or the above concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the protection scope of the present invention.

Claims

1. A fuel cell system all-in-one controller, characterized in that: The all-in-one controller includes a first input terminal, a second input terminal, an input EMI, a residual hydrogen discharge unit, an input capacitor, a DC / DC converter, a control system, an output capacitor, a PDU, an output relay unit, a protection unit, an output EMI, and an output terminal; wherein the first input terminal is externally connected to the fuel cell stack, and is internally connected to the output terminal through the input EMI, the residual hydrogen discharge unit, the input capacitor, the DC / DC converter, the output capacitor, the PDU, the output relay unit, the protection unit, and the output EMI in sequence; the output terminal is externally connected to the vehicle power battery; the second input terminal is externally connected to the low-voltage battery, and is internally connected in parallel to the two ends of the input capacitor; the control system is connected to the DC / DC converter and also communicates with the fuel cell system controller; the output relay unit includes a main positive and a main negative relay, wherein the main positive relay is connected in series to the positive line between the PDU and the protection unit; the main negative relay is connected in series to the negative line between the PDU and the protection unit.

2. The all-in-one controller for a fuel cell system according to claim 1, characterized in that: A current sensor A1 is connected in series on the high-voltage bus between the input EMI and the residual hydrogen discharge unit; a voltage sensor V1 is connected in parallel at both ends of the residual hydrogen discharge unit; a current sensor A2 is connected in series on the high-voltage bus between the input capacitor and the DC / DC converter; a current sensor A3 is connected in series on the high-voltage bus between the output capacitor and the PDU; a voltage sensor V2 is connected in parallel between the PDU and the output capacitor; a voltage sensor V3 is connected in parallel at the input end of the low-voltage pre-charging unit; a voltage sensor V4 is connected in parallel at the output end of the low-voltage pre-charging unit; and a voltage sensor V5 is connected in parallel at both ends of the battery.

3. The all-in-one controller for a fuel cell system according to claim 1, characterized in that: The residual hydrogen discharge unit comprises a normally open relay and a discharge resistor, wherein the normally open relay and the discharge resistor are connected in series and connected in parallel to the output end of the input EMI.

4. The all-in-one controller for a fuel cell system according to claim 1, characterized in that: The all-in-one controller also includes an ACP controller, the input end of the ACP controller is connected to the PDU via EMI, and the output end of the ACP controller is connected to the air compressor.

5. The all-in-one controller for a fuel cell system according to claim 1, characterized in that: A diode is connected in series on the high-voltage bus between the second input terminal and the input capacitor, wherein the anode of the diode is connected to the second input terminal, and the cathode of the diode is connected to one end of the input capacitor.

6. The all-in-one controller for a fuel cell system according to claim 1, characterized in that: The all-in-one controller further comprises an AC impedance detection device EIS, and the EIS is connected to the control system.

7. The all-in-one controller for a fuel cell system according to claim 1, characterized in that: The DC / DC converter adopts a BOOST boost circuit.

8. The all-in-one controller for a fuel cell system according to claim 1, characterized in that: The protection unit includes an output fuse, and the output fuse is connected in series to a high-voltage bus between the output relay unit and the output EMI.

9. An application method of the fuel cell system all-in-one controller according to claims 1-8, characterized in that: The method is applied to the power-on timing control of the all-in-one controller of the fuel cell system, and includes: The all-in-one controller connects the low-voltage power T30 and feeds back the low-voltage power-on status to the fuel cell system controller; The fuel cell system controller sends hardware enable to the all-in-one controller; The all-in-one controller starts CAN communication and starts self-test; when the all-in-one controller passes the self-test, the self-test pass status is fed back to the fuel cell system controller; The fuel cell system controller sends instructions to the all-in-one controller, the instructions including battery voltage detection, power battery voltage detection, and DC / DC low-voltage pre-charging instructions; The all-in-one controller executes the instructions in sequence, detects the battery voltage and the power battery voltage through sensors, and determines whether they are within a preset voltage range; If it is within the preset voltage range, it is considered that the fuel cell system meets the low-voltage pre-charging conditions. At this time, the all-in-one controller starts to perform low-voltage pre-charging: the all-in-one controller extracts electric energy from the low-voltage battery and feeds it back to the high-voltage bus at the front end of the input capacitor. Then the control system outputs a PWM signal to control the DC / DC controller to perform a voltage step-up conversion on the voltage across the input capacitor to charge the output capacitor. When the voltage of the output capacitor is pre-charged to a preset ratio of the vehicle power battery voltage, the main positive relay and the main negative relay are closed in turn, and then the high-voltage relay adhesion detection is performed. After the high-voltage relay adhesion detection is completed, the all-in-one controller uploads the pre-charge status of the DC / DC high-voltage side to the fuel cell system controller; When the fuel cell system controller detects that the high-pressure side pre-charging is successful, it sends the ACP speed command value and control mode request to the all-in-one controller; Correspondingly, the all-in-one controller drives the air compressor to operate and feeds back the speed data and the fuel cell stack voltage data to the fuel cell system controller; The fuel cell system controller sends a constant current instruction, a constant current limit, and a constant current mode request to the all-in-one controller; The all-in-one controller performs a constant current load mode on the fuel cell stack according to the constant current instruction, the constant current limit, and the constant current mode, and controls the fuel cell system to output stably.

10. An application method of the fuel cell system all-in-one controller according to claims 1-8, characterized in that: The method is applied to relay sticking detection of the fuel cell system all-in-one controller, comprising: The all-in-one controller first performs a self-test and then proceeds to the next step after passing the self-test; When the all-in-one controller detects the low-voltage battery voltage and determines whether the battery voltage is within the preset battery voltage range, if so, it is considered that the battery voltage is normal and proceeds to the next step; When the all-in-one controller detects the power battery voltage of the vehicle and determines whether the power battery voltage is within the preset power battery voltage range, if so, it is considered that the power battery voltage is normal and proceeds to the next step; Execute the low-voltage pre-charge instruction and determine whether the voltage pre-charged to the output capacitor reaches a preset ratio of the power battery voltage. If so, proceed to the next step; The all-in-one controller sends an instruction to close the main negative relay and determine whether there is current across the output capacitor; if so, it means that the main positive relay is stuck. At this time, the all-in-one controller reports a fault, returns to the self-test process, and waits for the system to process; if not, the all-in-one controller sends an instruction to disconnect the main negative relay, close the main positive relay, and determine whether there is current across the output capacitor at this time. If so, it means that the main negative relay is stuck. At this time, the all-in-one controller reports a fault, returns to the self-test process, and waits for the system to process; if not, it means that both the main positive relay and the main negative relay are not stuck. The all-in-one controller sends an instruction to close the main negative relay and end the sticking detection.

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