Liquid hydrogen cooling motor system performance test platform

Abstract

The invention provides a liquid hydrogen cooling motor system performance test platform, which is characterized in that a nitrogen cylinder group is connected with a twin-trawling test platform through a first joint, a liquid hydrogen storage tank is connected with a hydrogen cooling casing through an inlet pipe and is sequentially connected with a gas return pipe and a diffusion unit from the hydrogen cooling casing, and one interface of the nitrogen cylinder group is connected with the twin-trawling test platform through the first joint; one connector is connected to the hydrogen cooling motor, the other connector and the air return pipe are connected to the diffusion unit, and the water cooling machine shell is sequentially connected with the first water cooling connector, the radiator, the water tank, the circulating water pump and the second water cooling connector and is connected back to the water cooling machine shell from the second water cooling connector. The heat generated in a permanent magnet motor system with high energy density and maximum heat productivity can be effectively removed, and stable operation of the motor under a high-load condition is ensured.

Description

Technical Field

[0001] The present invention relates to the field of cryogenic equipment, and in particular to a liquid hydrogen cooling motor system performance testing platform and method. Background Art

[0002] Traditional cooling methods, such as air cooling or liquid cooling, can meet the heat dissipation needs of motors to a certain extent. However, for motors that pursue higher power density, these cooling methods often have limitations and are difficult to meet the needs of efficient heat dissipation.

[0003] Since the motor works under extreme conditions, traditional cooling methods may not be able to effectively remove the large amount of heat energy generated inside the motor, resulting in motor performance degradation or even damage. Liquid hydrogen cooling can provide efficient heat transfer and participate in the fuel cell as fuel after evaporation, thereby realizing energy recycling and increasing the overall energy efficiency of the system. In the prior art, there are already test platforms for motor systems and technical solutions for using liquid hydrogen to cool motors, but there is currently a lack of test platforms specifically for evaluating the performance of liquid hydrogen-cooled motors. Summary of the invention

[0004] In order to solve the above problems, the present invention proposes a liquid hydrogen cooled motor system performance testing platform and method.

[0005] The present invention is achieved through the following technical solutions:

[0006] The present invention proposes a liquid hydrogen cooling motor system performance test platform comprising a towing test platform, a supply unit, a discharge unit and a circulation unit, wherein:

[0007] The circulation unit comprises a radiator, a water tank and a circulation pump;

[0008] The supply unit includes a liquid hydrogen storage tank and a nitrogen cylinder group;

[0009] The towing test platform is provided with a first water-cooling joint, a second water-cooling joint, an inlet pipe, a return air pipe and a first joint. A water-cooled motor and a hydrogen-cooled motor are fixed in the towing test platform. The hydrogen-cooled motor and the water-cooled motor are respectively equipped with a hydrogen-cooled casing and a water-cooled casing. Temperature sensors are provided in the hydrogen-cooled casing and the water-cooled casing;

[0010] The nitrogen cylinder group is connected to the towing test platform through the first joint, the liquid hydrogen storage tank is connected to the hydrogen-cooled casing through the inlet pipe, and is connected to the return air pipe and the release unit in sequence from the hydrogen-cooled casing, one interface of the nitrogen cylinder group is connected to the towing test platform through the first joint, and the other interface and the return air pipe are connected to the release unit, the water-cooled casing is connected to the first water-cooled joint, the radiator, the water tank, the circulating water pump and the second water-cooled joint in sequence, and is connected back to the water-cooled casing from the second water-cooled joint.

[0011] Furthermore, the towing test platform includes a towing platform, a fixed base is provided at the bottom of the towing platform for bearing, two motor fixing frames are provided on the towing platform, and the hydrogen-cooled motor and the water-cooled motor are respectively fixed on the two motor fixing frames.

[0012] Furthermore, the towing test platform also includes a protective cover, which includes a box frame, a water-cooled side end plate and a hydrogen-cooled side end plate. The box frame is arranged on the outside of the towing platform, and the water-cooled side end plate and the hydrogen-cooled side end plate are arranged on both sides of the box frame.

[0013] Furthermore, the protective cover also includes a base and a bottom plate sequentially arranged at the bottom of the box frame, and an observation window is also arranged on the box frame. The towing platform is located in the closed space of the protective cover, and the closed space is under a slightly positive pressure.

[0014] Furthermore, the first water-cooling joint and the second water-cooling joint are arranged on the water-cooling side end plate, and the water-cooling side end plate is also provided with a water-cooling side gland assembly and a drawer assembly.

[0015] Furthermore, the inlet pipe, the first joint, and the return air pipe are arranged on the hydrogen-cooled side end plate, and a hydrogen-cooled side gland assembly is also arranged on the hydrogen-cooled side end plate.

[0016] Furthermore, it also includes a vaporizer, a first flow meter and a first valve, and the return air pipe is sequentially connected to the vaporizer, the first flow meter, the first valve and the dispersing unit.

[0017] Furthermore, it also includes a second flow meter and a second valve, and the second flow meter and the second valve are sequentially arranged between another interface of the nitrogen cylinder group and the discharging unit.

[0018] Furthermore, the liquid hydrogen cooled motor system performance test method comprises the following steps:

[0019] S1. Start the hydrogen-cooled motor and introduce liquid hydrogen into the towing test platform. The liquid hydrogen enters the hydrogen-cooled casing to cool the hydrogen-cooled motor;

[0020] S2. Fill the water tank with cooling water and start the circulation pump to allow the cooling water to enter the water-cooled casing for cooling;

[0021] S3. Connect the hydrogen-cooled motor and the water-cooled motor through a coupling and conduct a towing test;

[0022] S4. Record the parameters of the hydrogen-cooled motor and the water-cooled motor.

[0023] Furthermore, the towing test in step S3 includes the following steps:

[0024] S301. Record the temperature values ​​of the water-cooled motor and the hydrogen-cooled motor respectively;

[0025] S302. Start the four-quadrant rectifier and set the bus voltage to 600VDC;

[0026] S303. Start the inverters corresponding to the water-cooled motor and the hydrogen-cooled motor respectively, set the motor parameters, identify and start the water-cooled motor and the hydrogen-cooled motor respectively, ensure that the motor couplings are in the same direction, and stop after confirming that the direction and motor no-load vibration meet the requirements;

[0027] S304. Start the frequency converter of the hydrogen-cooled motor, set the motor speed, and drag the hydrogen-cooled motor to the rated speed;

[0028] S305. Set the water-cooled motor inverter to the torque mode, start the water-cooled motor inverter, and after completing the grid connection, set the water-cooled motor torque to the positive speed and negative torque corresponding to the power generation state;

[0029] S306. Starting from the maximum load of the hydrogen-cooled motor loading process, the load is gradually reduced to the minimum load in sequence, and the hydrogen-cooled motor is loaded at the six load points of 125%, 110%, 100%, 80%, 60%, and 40%;

[0030] S307. Record the voltage, current, power, speed, and frequency of the water-cooled motor and the hydrogen-cooled motor at each load point.

[0031] Beneficial effects of the present invention:

[0032] (1) The liquid hydrogen-cooled motor system performance test platform proposed in the present invention uses liquid hydrogen as a cooling medium, which can effectively remove the heat generated inside the permanent magnet motor system with high energy density and the highest heat generation, ensuring the stable operation of the motor under high load conditions. In addition, the present invention is also compatible with the high-power and normal heat generation motor towing test platform in the prior art, thereby expanding the test scope.

[0033] (2) The liquid hydrogen cooling motor system performance test platform proposed in the present invention is provided with a protective cover for the towing test platform. The protective cover is explosion-proof and has good sealing properties, can effectively isolate the external environment, and ensure the safety of the liquid hydrogen cooling system during operation. An observation window is provided on the protective cover, which can monitor in real time to avoid abnormal situations. The structure of the protective cover is also simple and easy to disassemble and maintain.

[0034] (3) The liquid hydrogen-cooled motor system performance test method proposed in the present invention can comprehensively and accurately evaluate the thermal performance, efficiency power density and other key performance indicators of the hydrogen-cooled motor, providing a reliable experimental basis for the practical application of liquid hydrogen cooling technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a connection structure diagram of the liquid hydrogen cooling motor system performance test platform of the present invention;

[0036] Figure 2 It is a structural diagram of a towing test platform of a liquid hydrogen cooling motor system performance test platform of the present invention;

[0037] Figure 3 It is a structural diagram of the towing platform of the liquid hydrogen cooling motor system performance test platform of the present invention;

[0038] In the figure: towing test platform 1, hydrogen-cooled motor 11, water-cooled motor 12, fixed base 13, motor fixing frame 14, towing platform 15, protective cover 2, bottom plate 21, base 22, box frame 23, water-cooled side end plate 24, extraction port assembly 25, water-cooled side gland assembly 26, first water-cooled joint 27, second water-cooled joint 28, observation window 29, first joint 210, inlet pipe 211, hydrogen-cooled side gland assembly 212, return air pipe 213, hydrogen-cooled side end plate 214;

[0039] The purpose, features and advantages of the present invention will be further described with reference to the accompanying drawings in conjunction with the embodiments. DETAILED DESCRIPTION

[0040] In order to more clearly and completely illustrate the technical solution of the present invention, the present invention is further described below in conjunction with the accompanying drawings.

[0041] Please refer to Figure 1-Figure 3 The present invention proposes a liquid hydrogen cooling motor system performance test platform including a towing test platform 1, a supply unit, a discharge unit and a circulation unit, wherein:

[0042] The circulation unit includes a radiator, a water tank and a circulation pump;

[0043] The supply unit includes a liquid hydrogen storage tank and a nitrogen cylinder group;

[0044] The towing test platform 1 is provided with a first water-cooling joint 27, a second water-cooling joint 28, an inlet pipe 211, a return air pipe 213 and a first joint 210. A water-cooled motor 12 and a hydrogen-cooled motor 11 are fixed in the towing test platform 1. The hydrogen-cooled motor 11 and the water-cooled motor 12 are respectively provided with a hydrogen-cooled casing and a water-cooled casing. Temperature sensors are provided in the hydrogen-cooled casing and the water-cooled casing.

[0045] The nitrogen cylinder group is connected to the towing test platform 1 through the first joint 210, the liquid hydrogen storage tank is connected to the hydrogen-cooled casing through the inlet pipe 211, and is connected to the return air pipe 213 and the release unit in sequence from the hydrogen-cooled casing. One interface of the nitrogen cylinder group is connected to the towing test platform 1 through the first joint 210, and the other interface and the return air pipe 213 are connected to the release unit. The water-cooled casing is connected to the first water-cooled joint 27, the radiator, the water tank, the circulating water pump and the second water-cooled joint 28 in sequence, and is connected back to the water-cooled casing from the second water-cooled joint 28.

[0046] In a specific embodiment, the hydrogen-cooled motor 11 and the water-cooled motor 12 are respectively equipped with a hydrogen-cooled casing and a water-cooled casing. The casing can be used as a motor housing and can also be used to cool the motor by injecting liquid hydrogen or low-temperature hydrogen as a medium. A series of sensors such as temperature are provided on the casing to monitor the real-time parameters of the motor. The liquid hydrogen storage tank is connected to the inlet pipe 211, and the liquid hydrogen enters the casing of the hydrogen-cooled motor 11 to cool the motor. The hydrogen converted by the liquid hydrogen absorption is discharged through the return air pipe 213. The circulating water pump injects the cooling water in the water tank into the casing of the water-cooled motor 12 through the second water-cooling joint 28 for cooling. The cooling water finally passes through the first The water-cooling joint 27 enters the radiator, returns to the water tank after cooling, and the nitrogen bottle group provides nitrogen for purging to the release unit, and also provides nitrogen to the nitrogen protective cover 2 in the towing test platform 1. The release unit processes the nitrogen and hydrogen after the test. The towing test platform 1 provided by the present invention uses liquid hydrogen as a cooling medium, which can effectively remove the heat generated inside the permanent magnet motor system with high energy density and the highest heat generation, and ensure the stable operation of the motor under high load conditions. In addition, the present invention is also compatible with the motor towing test platform 1 with high power and normal heat generation in the prior art, thereby expanding the test range.

[0047] Furthermore, the towing test platform 1 includes a towing platform 15 , a fixed base 2213 is provided at the bottom of the towing platform 15 for bearing, two motor fixing frames 14 are provided on the towing platform 15 , and the hydrogen-cooled motor 11 and the water-cooled motor 12 are fixed on the two motor fixing frames 14 respectively.

[0048] In a specific embodiment, a through hole is opened on the motor fixing frame 14 and fixedly connected with the towing platform 15. The two motor fixing frames 14 are used to fix two motors to be tested respectively. A plurality of through holes are opened on the motor fixing frame 14 and connected with the threaded holes opened on the towing platform 15 through bolts and nuts. The upper end surface of the fixed base 2213 has a T-shaped groove, which makes it more convenient to install and position the motor in the length direction of the towing platform 15.

[0049] Furthermore, the towing test platform 1 further includes a protective cover 2, which includes a box frame 23, a water-cooled side end plate 24 and a hydrogen-cooled side end plate 214, the box frame 23 is arranged outside the towing platform 15, and the water-cooled side end plate 24 and the hydrogen-cooled side end plate 214 are arranged on both sides of the box frame 23;

[0050] The protective cover 2 further comprises a base 22 and a bottom plate 21 which are sequentially arranged at the bottom of the box frame 23. The box frame 23 is also provided with an observation window 29. The towing platform 15 is located in the closed space of the protective cover 2, and the closed space is under a slight positive pressure.

[0051] In a specific embodiment, the protective cover 2 is used to seal the entire towing platform 15. Sealing gaskets are arranged between the base 22 and the bottom plate 21, between the base 22 and the box frame 23, between the observation window 29 and the box frame 23, and between the towing platform 15 and the bottom plate 21 to ensure the sealing of the protective cover 2. The protective cover 2 has the function of isolating air and safety explosion-proof. Liquid hydrogen enters the cooling shell of the motor under test through the protective cover 2 to absorb heat. After washing, it is converted into hydrogen and passes through the protective cover 2 to enter the inlet of the vaporizer to complete the cooling process of the motor system. The observation window 29 is used to observe the operating status of the internal hydrogen-cooled motor 11 system in real time, so as to facilitate timely detection of abnormal conditions. At the same time, the protective cover 2 has a simple structure and is more conducive to disassembly and maintenance.

[0052] Furthermore, the first water-cooling joint 27 and the second water-cooling joint 28 are arranged on the water-cooling side end plate 24, and the water-cooling side gland assembly 26 and the extraction port assembly 25 are also arranged on the water-cooling side end plate 24;

[0053] The inlet pipe 211 , the first joint 210 , and the return pipe 213 are arranged on the hydrogen-cooling side end plate 214 , and a hydrogen-cooling side gland assembly 212 is also arranged on the hydrogen-cooling side end plate 214 .

[0054] In a specific embodiment, the suction port assembly 25 is used to evacuate the interior of the protective cover 2, the water-cooled motor 12 is arranged on one side of the water-cooled side end plate 24, the hydrogen-cooled motor 11 is arranged on the hydrogen-cooled side end plate 214, and the hydrogen-cooled side gland assembly 212 and the water-cooled side gland assembly 26 are used to cooperate with the connecting joints.

[0055] Furthermore, it also includes a vaporizer, a first flow meter and a first valve. The return air pipe 213 is sequentially connected to the vaporizer, the first flow meter, the first valve and connected to the dispersing unit.

[0056] In a specific embodiment, the vaporizer is used to recover the cold energy of the low-temperature hydrogen, the first flow meter is used to monitor the flow rate of liquid hydrogen converted into hydrogen after the test, the first valve is used to control the on-off of the return air pipe 213, and the low-temperature hydrogen after cooling the motor is recovered through the vaporizer for cold energy, and then discharged into the discharging unit through the first flow meter and the first valve in sequence.

[0057] Furthermore, it also includes a second flow meter and a second valve, which are sequentially arranged between another interface of the nitrogen bottle group and the release unit.

[0058] In a specific implementation, the second flow meter is used to monitor the flow of the nitrogen bottle group, and the second valve is a solenoid valve used to control the on-off between the nitrogen bottle group and the release unit. During the motor cooling experiment, the second valve is opened, and then a large amount of nitrogen and hydrogen are mixed and safely discharged into the release unit.

[0059] Furthermore, the liquid hydrogen cooling motor system performance test method comprises the following steps:

[0060] S1. Start the hydrogen-cooled motor 11, introduce liquid hydrogen into the towing test platform 1, and the liquid hydrogen enters the hydrogen-cooled casing to cool the hydrogen-cooled motor 11;

[0061] S2. Fill the water tank with cooling water and start the circulation pump to allow the cooling water to enter the water-cooled casing for cooling;

[0062] S3. The hydrogen-cooled motor 11 and the water-cooled motor 12 are connected through a coupling to conduct a towing test;

[0063] S4. Record the parameters of the hydrogen-cooled motor 11 and the water-cooled motor 12.

[0064] Specifically, the liquid hydrogen storage tank is connected to the liquid hydrogen inlet pipe 211 of the towing test platform 1 through a hose, the liquid hydrogen outlet of the towing test platform 1 is connected to the hydrogen inlet of the vaporizer, the outlet of the nitrogen bottle group is connected to the first joint 210 of the towing test platform 1, and the return air pipe 213 of the towing test platform 1 is connected to the release unit through a hard pipe. The hydrogen-cooled motor 11 and the water-cooled motor are connected through a coupling to carry out the towing test. The hydrogen-cooled motor 11 is powered by the test bench inverter, so that the hydrogen-cooled motor 11 drives the water-cooled motor 12 to operate. The hydrogen-cooled motor 11 works in the motor state, and the water motor works in the generator state.

[0065] In one embodiment, the water-cooled motor 12 is cooled by water, the cooling water flow rate is 30L / min, and the water temperature is 65°C. The hydrogen-cooled motor 11 is cooled by liquid hydrogen. When the power is 80kW, the liquid hydrogen cooling flow rate is not less than 2.0L / min, when the power is 100kW, the liquid hydrogen cooling flow rate is not less than 2.5L / min, and when the power is 120kW, the liquid hydrogen cooling flow rate is not less than 3.3L / min. The pipeline through which the liquid hydrogen passes before entering the inlet of the liquid hydrogen motor needs to be wrapped with insulating material to ensure that the inlet temperature is around -253°C as much as possible.

[0066] Furthermore, the towing test in step S3 includes the following steps:

[0067] S301. Record the temperature values ​​of the water-cooled motor 12 and the hydrogen-cooled motor 11 respectively;

[0068] S302. Start the four-quadrant rectifier and set the bus voltage to 600VDC;

[0069] S303. Start the inverters corresponding to the water-cooled motor 12 and the hydrogen-cooled motor 11 respectively, set the motor parameters, identify and start the water-cooled motor 12 and the hydrogen-cooled motor 11 respectively, ensure that the motor couplings are in the same direction, and stop after confirming that the direction and the motor no-load vibration meet the requirements;

[0070] S304. Start the frequency converter of the hydrogen-cooled motor 11, set the motor speed, and drag the hydrogen-cooled motor 11 to the rated speed;

[0071] S305. Set the inverter of the water-cooled motor 12 to the torque mode, start the inverter of the water-cooled motor 12, and after the grid connection is completed, set the torque of the water-cooled motor 12 to the positive speed and negative torque corresponding to the power generation state;

[0072] S306. Starting from the maximum load of the hydrogen-cooled motor 11 loading process, the load is gradually reduced to the minimum load in sequence, and the hydrogen-cooled motor 11 is loaded at the six load points of 125%, 110%, 100%, 80%, 60%, and 40%;

[0073] S307. Record the voltage, current, power, speed, and frequency of the water-cooled motor 12 and the hydrogen-cooled motor 11 at each load point.

[0074] Specifically, the hydrogen-cooled motor 11 and the water-cooled motor 12 are tested in a pair-drag mode. The general test time is two hours or until the motor reaches a stable temperature. If during the test, the winding temperature of any one of the hydrogen-cooled motor 11 or the water-cooled motor 12 reaches 200°C, the test is terminated in advance and the temperature rise data at the time of shutdown is recorded. The clicked speed is controlled by the frequency of the inverter, and the rated speed is the speed of the motor at the rated frequency. Before reading the test data, the motor should reach thermal stability, and the stator winding temperature should not differ from the temperature measured during the load temperature rise test by more than 5°C. The present invention can comprehensively and accurately evaluate the thermal performance, efficiency, power density and other key performance indicators of the hydrogen-cooled motor 11 through the liquid hydrogen cooling motor system performance test method, and provide a reliable experimental basis for the practical application of liquid hydrogen cooling technology.

[0075] Of course, the present invention may have many other implementations. Based on this implementation, other implementations obtained by ordinary technicians in this field without any creative work are all within the scope of protection of the present invention.

Claims

1. A liquid hydrogen cooling motor system performance test platform, characterized in that: It includes a towing test platform, a supply unit, a release unit and a circulation unit, among which: The circulation unit comprises a radiator, a water tank and a circulation pump; The supply unit includes a liquid hydrogen storage tank and a nitrogen cylinder group; The towing test platform is provided with a first water-cooling joint, a second water-cooling joint, an inlet pipe, a return air pipe and a first joint. A water-cooled motor and a hydrogen-cooled motor are fixed in the towing test platform. The hydrogen-cooled motor and the water-cooled motor are respectively equipped with a hydrogen-cooled casing and a water-cooled casing. Temperature sensors are provided in the hydrogen-cooled casing and the water-cooled casing; The nitrogen cylinder group is connected to the towing test platform through the first joint, the liquid hydrogen storage tank is connected to the hydrogen-cooled casing through the inlet pipe, and is connected to the return air pipe and the release unit in sequence from the hydrogen-cooled casing, one interface of the nitrogen cylinder group is connected to the towing test platform through the first joint, and the other interface and the return air pipe are connected to the release unit, the water-cooled casing is connected to the first water-cooled joint, the radiator, the water tank, the circulating water pump and the second water-cooled joint in sequence, and is connected back to the water-cooled casing from the second water-cooled joint.

2. The liquid hydrogen cooled motor system performance test platform according to claim 1 is characterized in that: The towing test platform comprises a towing platform, a fixed base is arranged at the bottom of the towing platform for bearing, two motor fixing frames are arranged on the towing platform, and a hydrogen-cooled motor and a water-cooled motor are respectively fixed on the two motor fixing frames.

3. The liquid hydrogen cooled motor system performance test platform according to claim 1 is characterized in that: The towing test platform also includes a protective cover, which includes a box frame, a water-cooled side end plate and a hydrogen-cooled side end plate. The box frame is arranged on the outside of the towing platform, and the water-cooled side end plate and the hydrogen-cooled side end plate are arranged on both sides of the box frame.

4. The liquid hydrogen cooled motor system performance test platform according to claim 3 is characterized in that: The protective cover also includes a base and a bottom plate arranged in sequence at the bottom of the box frame. The box frame is also provided with an observation window. The towing platform is located in the closed space of the protective cover, and the closed space is under a slight positive pressure.

5. The liquid hydrogen cooled motor system performance test platform according to claim 3 is characterized in that: The first water-cooling joint and the second water-cooling joint are arranged on the water-cooling side end plate, and the water-cooling side end plate is also provided with a water-cooling side gland assembly and a drawer assembly.

6. The liquid hydrogen cooled motor system performance test platform according to claim 5 is characterized in that: The inlet pipe, the first joint, and the return air pipe are arranged on the hydrogen-cooling side end plate, and a hydrogen-cooling side gland assembly is also arranged on the hydrogen-cooling side end plate.

7. The liquid hydrogen cooled motor system performance test platform according to claim 1, characterized in that: It also includes a vaporizer, a first flow meter and a first valve. The return air pipe is sequentially connected to the vaporizer, the first flow meter, the first valve and the emission unit.

8. The liquid hydrogen cooled motor system performance test platform according to claim 1 is characterized in that: It also includes a second flow meter and a second valve, and the second flow meter and the second valve are sequentially arranged between another interface of the nitrogen cylinder group and the discharging unit.

9. A method for testing the performance of a liquid hydrogen-cooled motor system, using the liquid hydrogen-cooled motor system performance testing platform as described in any one of claims 1 to 8, characterized in that: The following steps are involved: S1. Start the hydrogen-cooled motor and introduce liquid hydrogen into the towing test platform. The liquid hydrogen enters the hydrogen-cooled casing to cool the hydrogen-cooled motor; S2. Fill the water tank with cooling water and start the circulation pump to allow the cooling water to enter the water-cooled casing for cooling; S3. Connect the hydrogen-cooled motor and the water-cooled motor through a coupling and conduct a towing test; S4. Record the parameters of the hydrogen-cooled motor and the water-cooled motor.

10. The liquid hydrogen cooled motor system performance testing method according to claim 9, characterized in that: The towing test in step S3 includes the following steps: S301. Record the temperature values ​​of the water-cooled motor and the hydrogen-cooled motor respectively; S302. Start the four-quadrant rectifier and set the bus voltage to 600VDC; S303. Start the inverters corresponding to the water-cooled motor and the hydrogen-cooled motor respectively, set the motor parameters, identify and start the water-cooled motor and the hydrogen-cooled motor respectively, ensure that the motor couplings are in the same direction, and stop after confirming that the direction and motor no-load vibration meet the requirements; S304. Start the frequency converter of the hydrogen-cooled motor, set the motor speed, and drag the hydrogen-cooled motor to the rated speed; S305. Set the water-cooled motor inverter to the torque mode, start the water-cooled motor inverter, and after completing the grid connection, set the water-cooled motor torque to the positive speed and negative torque corresponding to the power generation state; S306. Starting from the maximum load of the hydrogen-cooled motor loading process, the load is gradually reduced to the minimum load in sequence, and the hydrogen-cooled motor is loaded at the six load points of 125%, 110%, 100%, 80%, 60%, and 40%; S307. Record the voltage, current, power, speed, and frequency of the water-cooled motor and the hydrogen-cooled motor at each load point.

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