A fuel cell vehicle drive system and control method and control device

Abstract

The application discloses a fuel cell vehicle driving system and a control method and a control device thereof. The control method comprises the following steps: determining the working condition of the vehicle according to the vehicle speed; if the vehicle is in the idle speed working condition, controlling the first clutch in the mechanical connection structure of the vehicle to be disconnected, obtaining the charge state of the high-voltage battery in the vehicle, and controlling at least one of the fuel cell stack and the driving motor to charge the high-voltage battery when the charge state of the high-voltage battery is less than the first target charge state; if the vehicle is in the running working condition, obtaining the coolant temperature of the fuel cell stack, and switching the self-circulation cooling system or the cooling driving system to cool the coolant of the fuel cell stack according to the coolant temperature; and when the cooling driving system is used to cool the coolant of the fuel cell stack, the output state of the mechanical torque of the cooling driving system is controlled according to the outlet pressure of the working medium circulating pump in the cooling driving system. The energy utilization rate of the fuel cell stack is improved.

Description

Technical Field

[0001] This invention relates to the field of fuel cell technology, and in particular to a fuel cell vehicle drive system, control method, and control device. Background Technology

[0002] Currently, against the backdrop of the energy and environmental crisis, automakers worldwide are vigorously promoting the research and development of new energy vehicles. Fuel cell vehicles offer advantages such as zero emissions and low noise, and compared to electric vehicles, they boast higher fuel energy density and shorter refueling times. A fuel cell vehicle is a car powered by electricity generated by an onboard fuel cell device. It uses high-purity hydrogen as fuel, which reacts chemically with oxygen in the air within the fuel cell reactor to produce electricity, serving as the power source for the motor. However, currently, the fuel cell stack suffers from low energy utilization during idling and driving. Therefore, improving the energy utilization rate of the fuel cell stack is a pressing technical problem that researchers in this field need to solve. Summary of the Invention

[0003] This invention provides a fuel cell vehicle drive system, control method, and control device to improve the energy utilization rate of the fuel cell stack.

[0004] According to one aspect of the present invention, a control method for a fuel cell vehicle drive system is provided. The fuel cell vehicle drive system includes: a vehicle mechanical connection structure, a circuit structure, a self-circulating cooling system, and a cooling drive system; the control method includes:

[0005] The vehicle's speed is obtained, and its operating condition is determined based on the speed; the vehicle's operating condition includes idling and running conditions.

[0006] If the vehicle is in a parking idling state, the first clutch in the vehicle's mechanical connection structure is disconnected, and the charge state of the high-voltage battery in the vehicle is obtained. When the charge state of the high-voltage battery is less than the first target charge state, at least one of the fuel cell stack and the drive motor is controlled to charge the high-voltage battery. The first clutch is located between the transmission in the vehicle's mechanical connection structure and the drive motor in the circuit structure.

[0007] If the vehicle is in operation, the coolant temperature of the fuel cell stack is obtained, and the self-circulating cooling system or the cooling drive system is switched to cool the coolant of the fuel cell stack according to the coolant temperature; and when the cooling drive system cools the coolant of the fuel cell stack, the output state of the mechanical torque of the cooling drive system is controlled according to the outlet pressure of the working fluid circulation pump in the cooling drive system; wherein, the cooling drive system is also used to provide mechanical torque to the drive motor.

[0008] Furthermore, the system switches between a self-circulating cooling system and a cooling drive system to cool the coolant in the fuel cell stack based on the coolant temperature, including:

[0009] Compare the coolant temperature with the first preset temperature and the second preset temperature;

[0010] If the coolant temperature is lower than the first preset temperature, the self-circulating cooling system is controlled to cool the coolant.

[0011] If the coolant temperature is higher than the second preset temperature, the cooling drive system is controlled to cool the coolant.

[0012] Furthermore, the self-circulating cooling system includes: a fuel stack, a cooling working fluid pump, a three-way valve, and a heat exchanger; the cooling drive system includes: a heat exchanger, a working fluid circulation pump, a control valve, an expander, and a condenser; the cooling working fluid outlet of the fuel stack is connected to the inlet of the cooling working fluid pump; the outlet of the cooling working fluid pump is connected to the first end of the three-way valve; the second end of the three-way valve is connected to the first inlet of the heat exchanger; the third end of the three-way valve is connected to the cooling working fluid outlet of the fuel stack; the first outlet of the heat exchanger is connected to the cooling working fluid outlet of the fuel stack; the second inlet of the heat exchanger is connected to the outlet of the working fluid circulation pump; the second outlet of the heat exchanger is connected to the first end of the control valve, and the second end of the control valve is connected to the inlet of the expander; the third end of the control valve and the outlet of the expander are connected to the inlet of the condenser, and the outlet of the condenser is connected to the inlet of the working fluid circulation pump.

[0013] Controlling the cooling of the coolant in a self-circulating cooling system includes:

[0014] The first and third ends of the three-way valve are connected to allow the coolant to flow through the first and third ends of the three-way valve to the coolant inlet of the fuel stack after passing through the cooling medium pump.

[0015] Controlling the cooling drive system to cool the coolant includes:

[0016] The first and second ends of the three-way valve are connected to allow the coolant to enter the heat exchanger through the cooling medium pump, exchange heat with the cooling medium in the heat exchanger, and flow to the cooling medium inlet of the fuel cell stack through the first outlet end of the heat exchanger.

[0017] Furthermore, the control method for the fuel cell vehicle drive system includes controlling the mechanical torque output state of the cooling drive system based on the outlet pressure of the working fluid circulation pump in the cooling drive system.

[0018] Obtain the outlet pressure of the working fluid circulation pump in the cooling drive system, and compare the outlet pressure of the working fluid circulation pump with the first preset pressure and the second preset pressure.

[0019] If the outlet pressure of the working fluid circulation pump is less than the first preset pressure, the first and third ends of the control valve in the cooling drive system are opened to control the cooling drive system to stop outputting mechanical torque to the drive motor.

[0020] If the outlet pressure of the working fluid circulation pump is greater than the second preset pressure, the first and second ends of the control valve in the cooling drive system are opened to control the mechanical torque output of the cooling drive system to the drive motor.

[0021] Furthermore, controlling at least one of the fuel cell stack and the drive motor to charge the high-voltage battery when the state of charge of the high-voltage battery is less than the first target state of charge includes:

[0022] The control cooling drive system provides mechanical torque to the drive motor, which in turn converts the mechanical energy generated by the mechanical torque into electrical energy to charge the high-voltage battery; and the control fuel cell stack charges the high-voltage battery.

[0023] Furthermore, the control methods for fuel cell vehicle drive systems also include:

[0024] When the state of charge of the high-voltage battery is greater than the second target state of charge, the fuel cell stack is controlled to stop charging the high-voltage battery, while the drive motor continues to charge the high-voltage battery.

[0025] Furthermore, the charging power of the fuel cell stack is determined based on the charge range of the high-voltage battery; the charge of the high-voltage battery includes multiple charge ranges, and each charge range corresponds to a charging power.

[0026] Furthermore, controlling the cooling drive system to output the mechanical torque to the drive motor includes:

[0027] The speeds of the expander and the drive motor are obtained. When the difference between the speed of the drive motor and the speed of the expander is less than a first preset value, the driving disc and the driven disc of the second clutch are controlled to engage. The driving disc is fixedly connected to the mechanical output shaft of the expander, and the driven disc is fixedly connected to the drive shaft of the drive motor.

[0028] According to another aspect of the present invention, a control device for a fuel cell vehicle drive system is provided, the control device for the fuel cell vehicle drive system comprising:

[0029] The vehicle status determination module is used to obtain the vehicle's speed and determine the vehicle's operating condition based on the speed; the vehicle's operating condition includes idling and running conditions.

[0030] A high-voltage battery charging module is used to control the disconnection of a first clutch in the vehicle's mechanical connection structure and to obtain the charge state of the high-voltage battery in the vehicle when the vehicle is in a parking idling condition; and to control at least one of the fuel cell stack and the drive motor to charge the high-voltage battery when the charge state of the high-voltage battery is less than a first target charge state; wherein the first clutch is located between the transmission in the vehicle's mechanical connection structure and the drive motor in the circuit structure.

[0031] The cooling module is used to acquire the coolant temperature of the fuel cell stack when the vehicle is in operation, and switch between the self-circulating cooling system and the cooling drive system to cool the coolant of the fuel cell stack according to the coolant temperature; and when the cooling drive system is cooling the coolant of the fuel cell stack, it controls the output state of the mechanical torque of the cooling drive system according to the outlet pressure of the working fluid circulation pump in the cooling drive system; wherein, the cooling drive system is also used to provide mechanical torque to the drive motor.

[0032] According to another aspect of the present invention, a fuel cell vehicle drive system is provided, the fuel cell vehicle drive system comprising:

[0033] The circuit structure is used to convert electrical energy into driving force for the entire vehicle;

[0034] The self-circulating cooling system is used to cool the fuel stack when the coolant temperature is lower than a first preset temperature.

[0035] The cooling drive system is used to cool the fuel stack when the coolant temperature of the fuel stack is higher than a second preset temperature, and to provide power to the drive motor in the mechanical connection structure of the vehicle.

[0036] The vehicle mechanical connection structure includes a first clutch, a drive motor, and a transmission. The first clutch is located between the transmission in the vehicle mechanical connection structure and the drive motor in the circuit structure. The vehicle mechanical connection structure is used to convert the power generated in the cooling drive system and the circuit structure into the driving force of the vehicle.

[0037] The control method for a fuel cell vehicle drive system provided in this invention acquires the vehicle's speed and determines the vehicle's operating condition based on that speed. When the vehicle is in a stationary idling state, the first clutch in the vehicle's mechanical connection structure is disconnected, and the charge state of the high-voltage battery in the vehicle is acquired. When the charge state of the high-voltage battery is less than a first target charge state, at least one of the fuel cell stack and the drive motor is controlled to charge the high-voltage battery. During the process of the drive motor charging the high-voltage battery, the mechanical energy generated by the cooling drive system is converted into electrical energy of the high-voltage battery, increasing the energy utilization rate of the fuel cell stack. When the vehicle is in a running state, the coolant temperature of the fuel cell stack is acquired. When the cooling drive system cools the coolant of the fuel cell stack, the output state of the mechanical torque of the cooling drive system is controlled based on the outlet pressure of the working fluid circulation pump in the cooling drive system. When the outlet pressure of the working fluid circulation pump in the cooling drive system is high, the cooling drive system participates in the output of mechanical torque, which can convert the waste heat generated by the fuel cell stack into the power of the drive motor, further increasing the energy utilization rate of the fuel cell stack.

[0038] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0040] Figure 1 This is a flowchart of a control method for a fuel cell vehicle drive system according to an embodiment of the present invention;

[0041] Figure 2 This is a schematic diagram of the structure of a fuel cell vehicle drive system according to an embodiment of the present invention;

[0042] Figure 3 This is a schematic diagram of the structure of a control device for a fuel cell vehicle drive system according to an embodiment of the present invention. Detailed Implementation

[0043] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0044] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0045] This invention provides a control method for a fuel cell vehicle drive system. Figure 1 This is a flowchart of a control method for a fuel cell vehicle drive system according to an embodiment of the present invention. Figure 2 This is a schematic diagram of a fuel cell vehicle drive system according to an embodiment of the present invention, with reference to... Figure 1 and Figure 2 The fuel cell vehicle drive system includes: a vehicle mechanical connection structure, a circuit structure, a self-circulating cooling system, and a cooling drive system; the control method includes:

[0046] S110. Obtain the vehicle's speed and determine the vehicle's operating condition based on the speed; the vehicle's operating condition includes idling and running conditions.

[0047] Specifically, the vehicle speed can be detected in real time by the on-board speed sensor. When the speed sensor's detection result is 0, the vehicle's operating condition can be determined to be a stationary idling condition; when the speed sensor's detection result is not 0, the vehicle's operating condition can be determined to be a running condition.

[0048] S120. If the vehicle is in a parking idling state, the first clutch in the vehicle's mechanical connection structure is disconnected, and the charge state of the high-voltage battery in the vehicle is obtained. When the charge state of the high-voltage battery is less than the first target charge state, at least one of the fuel cell stack and the drive motor is controlled to charge the high-voltage battery. The first clutch is located between the transmission in the vehicle's mechanical connection structure and the drive motor in the circuit structure.

[0049] The circuit structure includes a fuel cell stack 171, a high-voltage battery 181, and a drive motor 153. The vehicle mechanical connection structure includes a first clutch 156, a transmission 152, and a drive motor 153. The drive motor 153 belongs to both the vehicle mechanical connection structure and the circuit structure.

[0050] Specifically, controlling the disconnection of the first clutch 156 in the vehicle's mechanical connection structure can prevent the mechanical energy generated by the cooling drive system from being converted into the vehicle's driving force during the charging process of the high-voltage battery 181, thereby improving the charging efficiency of the high-voltage battery 181. The charge level of the high-voltage battery 181 can be collected by the battery management system under the vehicle control system. Specifically, when the charge state of the high-voltage battery 181 is less than the first target charge state, it indicates that the high-voltage battery's charge is low, and it needs to be charged by at least one of the fuel cell stack 171 and the drive motor 153. At least one can be one or more; for example, the high-voltage battery 181 can be charged by the fuel cell stack 171, or it can be charged by both the fuel cell stack 171 and the drive motor 153. This embodiment of the invention does not limit this, as long as the charging requirements are met. During the process of the drive motor 153 participating in charging the high-voltage battery 181, the mechanical energy generated by the cooling drive system is converted into electrical energy in the high-voltage battery 181, increasing the energy utilization rate of the fuel cell stack 171.

[0051] S130. If the vehicle is in operation, the coolant temperature of the fuel cell stack is obtained, and the self-circulating cooling system or the cooling drive system is switched to cool the coolant of the fuel cell stack according to the coolant temperature; and when the cooling drive system cools the coolant of the fuel cell stack, the output state of the mechanical torque of the cooling drive system is controlled according to the outlet pressure of the working fluid circulation pump in the cooling drive system; wherein, the cooling drive system is also used to provide mechanical torque to the drive motor.

[0052] The cooling drive system includes a working fluid circulation pump 161. The coolant temperature of the fuel cell stack 171 can be obtained from a temperature sensor installed within the self-circulating cooling system. The type of temperature sensor can be set according to actual conditions; this embodiment of the invention does not limit this, as long as it meets the experimental requirements. When the coolant temperature of the fuel cell stack 171 is low, cooling the coolant through the self-circulating cooling system is sufficient. When the coolant temperature of the fuel cell stack 171 is high, the cooling drive system is needed to cool the coolant. Specifically, when the outlet pressure of the working fluid circulation pump 161 in the cooling drive system is low, the cooling drive system does not participate in the output of mechanical torque. When the outlet pressure of the working fluid circulation pump 161 in the cooling drive system is high, the cooling drive system participates in the output of mechanical torque, converting the waste heat generated by the fuel cell stack 171 into the power of the drive motor 153, thereby increasing the energy utilization rate of the fuel cell stack 171.

[0053] The control method for a fuel cell vehicle drive system provided in this embodiment of the invention acquires the vehicle's speed and determines the vehicle's operating condition based on that speed. When the vehicle is in a stationary idling state, the first clutch 156 in the vehicle's mechanical connection structure is disconnected, and the charge state of the high-voltage battery 181 in the vehicle is acquired. When the charge state of the high-voltage battery 181 is less than a first target charge state, at least one of the fuel cell stack 171 and the drive motor 153 is controlled to charge the high-voltage battery 181. During the process of the drive motor 153 participating in charging the high-voltage battery 181, the mechanical energy generated by cooling the drive system is converted into... The electrical energy from the high-voltage battery 181 increases the energy utilization rate of the fuel cell stack 171. When the vehicle is in operation, the coolant temperature of the fuel cell stack 171 is obtained. When the cooling drive system cools the coolant of the fuel cell stack 171, the output state of the mechanical torque of the cooling drive system is controlled according to the outlet pressure of the working fluid circulation pump 161 in the cooling drive system. When the outlet pressure of the working fluid circulation pump 161 in the cooling drive system is large, the cooling drive system participates in the output of mechanical torque, which can convert the waste heat generated by the action of the fuel cell stack 171 into the power of the drive motor 153, further increasing the energy utilization rate of the fuel cell stack 171.

[0054] Optional, see reference Figure 2 The system switches between a self-circulating cooling system and a cooling drive system to cool the coolant in the fuel stack 171 based on the coolant temperature, including:

[0055] Compare the coolant temperature with the first preset temperature and the second preset temperature;

[0056] If the coolant temperature is lower than the first preset temperature, the self-circulating cooling system is controlled to cool the coolant.

[0057] If the coolant temperature is higher than the second preset temperature, the cooling drive system is controlled to cool the coolant.

[0058] The first preset temperature and the second preset temperature can be set according to the actual situation. This embodiment of the invention does not limit this. For example, the first preset temperature can be 70°C and the second preset temperature can be 80°C.

[0059] Specifically, when the coolant temperature of the fuel cell stack 171 is lower than the first preset temperature, it indicates that the coolant temperature of the fuel cell stack 171 is not too high. Cooling the coolant of the fuel cell stack 171 through the self-circulating cooling system is sufficient to meet the requirements. At this time, the vehicle controller controls the second clutch 154 to disengage, reducing the drag loss of the expander 165 on the drive motor 153 in the cooling drive system, thereby improving the service life of the expander 165. When the coolant temperature of the fuel cell stack 171 is higher than the first preset temperature, it indicates that the coolant temperature of the fuel cell stack 171 is too high. Cooling the coolant of the fuel cell stack 171 through the self-circulating cooling system is insufficient to meet the requirements. At this time, the coolant of the fuel cell stack 171 needs to be cooled through the cooling drive system. If, during the cooling process of the cooling drive system on the coolant of the fuel cell stack 171, the coolant temperature of the fuel cell stack 171 is lower than the second preset temperature but higher than the first preset temperature, the cooling drive system continues to cool the coolant of the fuel cell stack 171 until the coolant temperature of the fuel cell stack 171 is lower than the first preset temperature. Then, the system switches back to the self-circulating cooling system to cool the coolant of the fuel cell stack 171, thus avoiding frequent switching between the cooling drive system and the self-circulating cooling system.

[0060] Optionally, the self-circulating cooling system includes: a fuel stack 171, a cooling working fluid pump 172, a three-way valve 173, and a heat exchanger 162; the cooling drive system includes: a heat exchanger 162, a working fluid circulation pump 161, a control valve 163, an expander 165, and a condenser 166; the cooling working fluid outlet of the fuel stack 171 is connected to the inlet of the cooling working fluid pump 172; the outlet of the cooling working fluid pump 172 is connected to the first end of the three-way valve 173; the second end of the three-way valve 173 is connected to the first inlet of the heat exchanger 162; and the third end of the three-way valve 173 is connected to the fuel stack 171. The cooling working fluid outlet of the fuel cell stack 171 is connected; the first outlet of the heat exchanger 162 is connected to the cooling working fluid outlet of the fuel cell stack 171; the second inlet of the heat exchanger 162 is connected to the outlet of the working fluid circulation pump 161; the second outlet of the heat exchanger 162 is connected to the first end of the control valve 163, and the second end of the control valve 163 is connected to the inlet of the expander 165; the third end of the control valve 163 and the outlet of the expander 165 are connected to the inlet of the condenser 166, and the outlet of the condenser 166 is connected to the inlet of the working fluid circulation pump 161.

[0061] Controlling the cooling of the coolant in a self-circulating cooling system includes:

[0062] The first and third ends of the three-way valve 173 are connected so that the coolant flows through the first and third ends of the three-way valve 173 to the coolant inlet end of the fuel stack 171 after passing through the coolant pump 172.

[0063] Controlling the cooling drive system to cool the coolant includes:

[0064] The first and second ends of the three-way valve 173 are connected so that the coolant enters the heat exchanger 162 through the cooling medium pump 172, exchanges heat with the cooling medium in the heat exchanger 162, and flows to the cooling medium inlet of the fuel stack 171 through the first outlet end of the heat exchanger 162.

[0065] Specifically, the coolant in the fuel cell stack 171 enters the three-way valve 173 through the cooling working fluid pump 172. When the temperature of the fuel cell stack coolant is lower than the first preset temperature, the first pipe 174b of the three-way valve 173 opens and the second pipe 174a closes, allowing the fuel cell stack coolant to enter the fuel cell stack 171 through the first pipe 174b for cooling, thus achieving self-circulating cooling. When the temperature of the coolant in the fuel cell stack 171 is higher than the second preset temperature, the first pipe 174b of the three-way valve 173 closes and the second pipe 174a opens, allowing the coolant in the fuel cell stack 171 to enter the heat exchanger 162 through the second pipe 174a. After heat exchange in the heat exchanger 162, the coolant then enters the fuel cell stack 171 for cooling, thus achieving further cooling cycle.

[0066] Since the rotational speed of the cooling working fluid pump 172 affects the flow rate of the coolant in the fuel cell stack 171, the higher the rotational speed of the cooling working fluid pump 172, the greater the circulation flow rate of the coolant in the fuel cell stack 171, and the more significant the heat dissipation of the fuel cell stack 171. Specifically, different pulse width modulation (PWM) duty cycles can be output according to different coolant temperatures of the fuel cell stack 171, thereby controlling the rotational speed of the cooling working fluid pump 172. For example, the duty cycle adjustment can be obtained by looking up a table of cooling working fluid pump rotational speed adjustment. Table 1 shows the correspondence between different fuel cell stack coolant temperatures and the duty cycle adjustment of the cooling working fluid pump rotational speed. As shown in Table 1, the correspondence between the fuel cell stack coolant temperature and the duty cycle adjustment of the cooling working fluid pump rotational speed is a linear correspondence.

[0067] Table 1. Comparison of Coolant Temperature and Coolant Pump Speed ​​Adjustment Duty Cycle for Fuel Stacks

[0068]

[0069] Optional, see reference Figure 2 The mechanical torque output state of the cooling drive system is controlled based on the outlet pressure of the working fluid circulation pump 161 in the cooling drive system, including:

[0070] Obtain the outlet pressure of the working fluid circulation pump 161 in the cooling drive system, and compare the outlet pressure of the working fluid circulation pump 161 with the first preset pressure and the second preset pressure.

[0071] If the outlet pressure of the working fluid circulation pump 161 is less than the first preset pressure, the first and third ends of the control valve 163 in the cooling drive system are opened to control the cooling drive system to stop outputting mechanical torque to the drive motor 153.

[0072] If the outlet pressure of the working fluid circulation pump 161 is greater than the second preset pressure, the first and second ends of the control valve 163 in the cooling drive system are opened to control the cooling drive system to output mechanical torque to the drive motor 153.

[0073] The outlet pressure of the working fluid circulation pump 161 can be obtained from the pressure sensor installed at the outlet of the working fluid circulation pump 161. The first preset pressure and the second preset pressure can be set according to the actual situation. For example, the first preset pressure can be 15 bar and the second preset pressure can be 18 bar. This embodiment of the invention does not limit this.

[0074] Specifically, when the outlet pressure of the working fluid circulation pump 161 is less than the first preset pressure, it indicates that the outlet pressure of the working fluid circulation pump 161 is low. The flow through the expander 165 will have a certain impact on the circulation of the cooling working fluid in the cooling drive system. At this time, after the cooling working fluid in the cooling drive system passes through the control valve 163, the vehicle controller controls the first branch 164b to open and the second branch 164a to close, so that the cooling working fluid flows through the first branch 164b and enters the condenser 166 for cooling. At this time, the vehicle controller needs to control the second clutch 154 to disengage, reduce the drag loss of the expander 165 on the drive motor 153 in the cooling drive system, and further improve the service life of the expander 165. During the cooling process of the working fluid entering the condenser 166, the condenser 166 and the condenser fan 167 work together to cool the working fluid. Different pulse width modulation (PWM) duty cycles can be output according to different outlet pressures of the working fluid circulation pump 161, thereby controlling the speed of the condenser fan 167. For example, the duty cycle of the condenser fan speed adjustment can be obtained by looking up a table. Table 2 shows the correspondence between the outlet pressure of different working fluid circulation pumps and the duty cycle of the condenser fan speed adjustment. As shown in Table 2, the correspondence between the outlet pressure of the working fluid circulation pump and the duty cycle of the condenser fan speed adjustment is a linear correspondence.

[0075] Table 2: Comparison of Working Fluid Circulation Pump Outlet Pressure and Condenser Fan Speed ​​Adjustment Duty Cycle

[0076] Condenser fan speed adjustment duty cycle 30％ 50％ 70％ 100％

[0077] When the outlet pressure of the working fluid circulation pump 161 is greater than the second preset pressure, it indicates that the outlet pressure of the working fluid circulation pump 161 is relatively large. At this time, after the cooling working fluid in the cooling drive system passes through the control valve 163, the vehicle controller controls the second branch 164a to open and the first branch 164b to close, so that the cooling working fluid flows through the second branch 164a, causing the cooling drive system to output mechanical torque to the drive motor 153, converting the waste heat generated by the fuel cell stack 171 into the power of the drive motor 153, thereby increasing the energy utilization rate of the fuel cell stack 171.

[0078] As the cooling drive system operates for longer periods, the expander 165 generates more and more mechanical energy. When the expander 165 and the high-voltage battery 181 work together to make the total output torque generated by the drive motor 153 greater than the system's required torque, the vehicle controller reduces the power supply to the high-voltage battery 181 at a first preset frequency. This greatly increases the energy utilization rate of the fuel cell stack 171 and saves the power of the high-voltage battery 181. The first preset frequency can be designed according to actual conditions, and this embodiment of the invention does not impose any restrictions on it.

[0079] Optional, see reference Figure 2 When the state of charge of the high-voltage battery 181 is less than the first target state of charge, controlling at least one of the fuel stack 171 and the drive motor 153 to charge the high-voltage battery 181 includes:

[0080] The control cooling drive system provides mechanical torque to the drive motor 153 so that the mechanical energy generated by the mechanical torque is converted into electrical energy to charge the high-voltage battery 181; and the control fuel stack 171 is used to charge the high-voltage battery 181.

[0081] Specifically, by charging the high-voltage battery 181 together with the fuel cell stack 171 and the drive motor 153, the charging efficiency of the high-voltage battery 181 can be increased, and the operation problems of one or more vehicle systems can be avoided due to untimely charging of the high-voltage battery 181.

[0082] Optional, see reference Figure 2 The control methods for fuel cell vehicle drive systems also include:

[0083] When the charge state of the high-voltage battery 181 is greater than the second target charge state, the control fuel stack 171 stops charging the high-voltage battery 181, while the drive motor 153 continues to charge the high-voltage battery 181.

[0084] Specifically, when the state of charge of the high-voltage battery 181 is greater than the second target state of charge, it means that the power of the high-voltage battery 181 can meet the normal operation of the vehicle system. Controlling the fuel cell stack 171 to stop charging the high-voltage battery 181 can reduce the fuel consumption of the fuel cell stack 171 without affecting the normal operation of the vehicle system, while maintaining the drive motor 153 to charge the high-voltage battery 181. The waste heat generated by the operation of the fuel cell stack 171 is converted into the power of the drive motor 153, which can further increase the energy utilization rate of the fuel cell stack 171.

[0085] Optionally, the charging power of the fuel cell stack is determined based on the charge range of the high-voltage battery; the charge of the high-voltage battery includes multiple charge ranges, and each charge range corresponds to a charging power.

[0086] In this context, "multiple" can be understood as two or more. For example, this embodiment of the invention uses five charge ranges as an example for illustration, and the specific description is as follows:

[0087] When the charge of the high-voltage battery is low, a larger fuel cell charging power is designed; when the charge of the high-voltage battery is high, a more gradual fuel cell charging power is designed. Furthermore, to ensure the operational stability of the fuel cell stack, a stepped control is adopted for the charging power of the fuel cell stack. This ensures that the fuel cell stack can operate at a constant power demand within a small range of charge variation. The corresponding power can be obtained from a fuel cell stack charging power lookup table. Table 3 shows the relationship between different high-voltage battery charges and fuel cell stack charging power.

[0088] Table 3: Comparison of High-Voltage Battery Charge and Fuel Stack Charging Power Optional, see reference Figure 2 Controlling the mechanical torque output of the cooling drive system to the drive motor includes:

[0089] The rotational speeds of the expander 165 and the drive motor 153 are obtained. When the difference between the rotational speed of the drive motor 153 and the rotational speed of the expander 165 is less than a first preset value, the driving disc and the driven disc of the second clutch 154 are controlled to engage. The driving disc is fixedly connected to the mechanical output shaft of the expander 165, and the driven disc is fixedly connected to the drive shaft of the drive motor 153.

[0090] The first preset value can be set according to actual conditions, and this embodiment of the invention does not limit this. For example, the first preset value can be 200 r / min. Specifically, the rotational speed of the expander 165 can be detected by a first speed sensor installed on the expander 165, and the rotational speed of the drive motor 153 can be detected by a second speed sensor installed on the drive motor 153. The vehicle controller acquires the first rotational speed collected by the first speed sensor and the second rotational speed collected by the second speed sensor in real time, and calculates the difference between the first and second rotational speeds acquired at the same time. This difference is compared with the first preset value set in the vehicle controller. When the difference between the rotational speed of the drive motor 153 and the rotational speed of the expander 165 is less than the first preset value, the driving plate and driven plate of the second clutch 154 are controlled to engage. This can reduce the transient slippage vibration generated by the second clutch 154 during engagement, thereby improving the service life of the second clutch 154.

[0091] This invention provides a control device for a fuel cell vehicle drive system. Figure 3 This is a schematic diagram of the structure of a control device for a fuel cell vehicle drive system according to an embodiment of the present invention. (Refer to...) Figure 3 The control unit 300 for the fuel cell vehicle drive system includes:

[0092] The vehicle status determination module 310 is used to obtain the vehicle's driving speed and determine the vehicle's operating condition based on the vehicle's driving speed; the vehicle's operating condition includes idling condition and running condition.

[0093] The high-voltage battery charging module 320 is used to control the disconnection of the first clutch in the vehicle's mechanical connection structure and obtain the charge state of the high-voltage battery in the vehicle when the vehicle is in a parking idling condition, and to control at least one of the fuel cell stack and the drive motor to charge the high-voltage battery when the charge state of the high-voltage battery is less than a first target charge state; wherein, the first clutch is located between the transmission in the vehicle's mechanical connection structure and the drive motor in the circuit structure.

[0094] The cooling module 330 is used to acquire the coolant temperature of the fuel cell stack when the vehicle is in operation, and switch between the self-circulating cooling system and the cooling drive system to cool the coolant of the fuel cell stack according to the coolant temperature; and when the cooling drive system cools the coolant of the fuel cell stack, it controls the output state of the mechanical torque of the cooling drive system according to the outlet pressure of the working fluid circulation pump in the cooling drive system; wherein, the cooling drive system is also used to provide mechanical torque to the drive motor.

[0095] Furthermore, the cooling module 330 includes:

[0096] A temperature comparison unit is used to compare the coolant temperature with a first preset temperature and a second preset temperature.

[0097] The self-circulating cooling system cooling unit is used to control the self-circulating cooling system to cool the coolant when the coolant temperature is lower than the first preset temperature.

[0098] The cooling drive system cooling unit is used to control the cooling drive system to cool the coolant when the coolant temperature is higher than a second preset temperature.

[0099] Furthermore, the self-circulating cooling system includes: a fuel cell stack, a cooling working fluid pump, and a three-way valve; the cooling drive system includes: a heat exchanger, a working fluid circulation pump, a control valve, an expander, and a condenser; the cooling working fluid outlet of the fuel cell stack is connected to the inlet of the cooling working fluid pump; the outlet of the cooling working fluid pump is connected to the first end of the three-way valve; the second end of the three-way valve is connected to the first inlet of the heat exchanger; the third end of the three-way valve is connected to the cooling working fluid outlet of the fuel cell stack; the first outlet of the heat exchanger is connected to the cooling working fluid outlet of the fuel cell stack; the second inlet of the heat exchanger is connected to the outlet of the working fluid circulation pump; the second outlet of the heat exchanger is connected to the first end of the control valve, and the second end of the control valve is connected to the inlet of the expander; the third end of the control valve and the outlet of the expander are connected to the inlet of the condenser, and the outlet of the condenser is connected to the inlet of the working fluid circulation pump;

[0100] The self-circulating cooling system cooling unit is used for:

[0101] The first and third ends of the three-way valve are connected to allow the coolant to flow through the first and third ends of the three-way valve to the coolant inlet of the fuel stack after passing through the cooling medium pump.

[0102] The cooling drive system cooling unit is used for:

[0103] The first and second ends of the three-way valve are connected to allow the coolant to enter the heat exchanger through the cooling medium pump, exchange heat with the cooling medium in the heat exchanger, and flow to the cooling medium inlet of the fuel cell stack through the first outlet end of the heat exchanger.

[0104] Furthermore, the cooling module 330 also includes:

[0105] The pressure acquisition unit is used to acquire the outlet pressure of the working fluid circulation pump in the cooling drive system and compare the outlet pressure of the working fluid circulation pump with a first preset pressure and a second preset pressure.

[0106] The mechanical torque pause output unit is used to control the first and third ends of the control valve in the cooling drive system to open when the outlet pressure of the working fluid circulation pump is less than the first preset pressure, so as to control the cooling drive system to pause the output of mechanical torque to the drive motor.

[0107] The mechanical torque output unit is used to control the first and second ends of the control valve in the cooling drive system to open when the outlet pressure of the circulating pump is greater than the second preset pressure, so as to control the cooling drive system to output mechanical torque to the drive motor.

[0108] Furthermore, the high-voltage battery charging module 320 is used for:

[0109] The control cooling drive system provides mechanical torque to the drive motor, which in turn converts the mechanical energy generated by the mechanical torque into electrical energy to charge the high-voltage battery; and the control fuel cell stack charges the high-voltage battery.

[0110] Furthermore, the high-voltage battery charging module 320 is also used for:

[0111] When the state of charge of the high-voltage battery is greater than the second target state of charge, the control fuel stack stops charging the high-voltage battery, while the drive motor continues to charge the high-voltage battery.

[0112] Furthermore, the charging power of the fuel cell stack is determined based on the charge range of the high-voltage battery; the charge of the high-voltage battery includes multiple charge ranges, and each charge range corresponds to a charging power.

[0113] Furthermore, the mechanical torque output unit is used for:

[0114] The speeds of the expander and the drive motor are obtained. When the difference between the speed of the drive motor and the speed of the expander is less than a first preset value, the driving disc and the driven disc of the second clutch are controlled to engage. The driving disc is fixedly connected to the mechanical output shaft of the expander, and the driven disc is fixedly connected to the drive shaft of the drive motor.

[0115] The control device for the fuel cell vehicle drive system provided in the embodiments of the present invention can execute the control method for the fuel cell vehicle drive system provided in any embodiment of the present invention, and has the corresponding functional modules and beneficial effects of executing the method.

[0116] This invention also provides a fuel cell vehicle drive system, see reference. Figure 2 The fuel cell vehicle drive system includes:

[0117] The circuit structure is used to convert electrical energy into driving force for the entire vehicle;

[0118] A self-circulating cooling system is used to cool the fuel stack 171 when the coolant temperature of the fuel stack 171 is lower than a first preset temperature.

[0119] The cooling drive system is used to cool the fuel stack 171 when the coolant temperature of the fuel stack 171 is higher than the second preset temperature, and to provide power to the drive motor 153 in the mechanical connection structure of the vehicle.

[0120] The vehicle mechanical connection structure includes a first clutch 156, a drive motor 153, and a transmission 152. The first clutch 156 is located between the transmission 152 in the vehicle mechanical connection structure and the drive motor 153 in the circuit structure. The vehicle mechanical connection structure is used to convert the power generated in the cooling drive system and the circuit structure into the driving force of the vehicle.

[0121] Specifically, the circuit structure includes a fuel cell stack 171, a high-voltage battery 181, an inverter 155, and a drive motor 153.

[0122] The fuel cell stack 171 is used to chemically react high-purity hydrogen and oxygen to generate electrical energy and output the electrical energy to the high-voltage battery 181; the high-voltage battery 181 is used to store high-voltage electrical energy; the inverter 155 is used to realize the mutual conversion between AC and DC power; the drive motor 153 is used to convert electrical energy into mechanical energy and output rotational torque after receiving AC power output from the inverter.

[0123] The self-circulating cooling system includes: a fuel stack 171, a cooling working fluid pump 172, a three-way valve 173, and a heat exchanger 162.

[0124] The cooling medium pump 172 is used to realize the circulation of the cooling medium in the self-circulating cooling system; the three-way valve 173 is used to control the flow direction of the cooling medium; the heat exchanger 162 is used to transfer the waste heat generated by the fuel stack 171 to the cooling drive system.

[0125] The cooling drive system includes: a heat exchanger 162, a working fluid circulation pump 161, a control valve 163, an expander 165, and a condenser 166.

[0126] The working fluid circulation pump 161 is used to transport the liquid organic working fluid to the heat exchanger 162 for heat exchange; the control valve 163 is used to realize different flow directions of the organic working fluid according to different application scenarios; the expander 165 is used to assist the drive motor 153; the condenser 166 dissipates heat from the organic working fluid flowing through it and converts the low-pressure organic working fluid from gaseous to liquid state.

[0127] The mechanical connection structure of the vehicle includes: left front wheel 110, right front wheel 120, front axle differential 151, transmission 152, drive motor 153, inverter 155, first clutch 156 and second clutch 154.

[0128] The front axle differential 151 is used to receive torque from the transmission 152, thereby driving the left front wheel 110 and the right front wheel 120 on the vehicle drive axle to rotate at different speeds, achieving smooth steering for the vehicle. The transmission 152 adjusts the output torque value by changing the speed ratio of different gears. The first clutch 156 is used to disengage when the vehicle is stationary to facilitate better charging of the high-voltage battery, and also to transmit driving force to the transmission 152 when the vehicle is in motion. The second clutch 154 is used to transmit the torque generated by the expander 165 to the drive motor 153.

[0129] The fuel cell vehicle drive system provided in this embodiment of the invention is controlled by the control method for the fuel cell vehicle drive system described in any embodiment of the invention. It has the same technical effects, and will not be repeated here.

[0130] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0131] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A control method for a fuel cell vehicle drive system, characterized in that, The fuel cell vehicle drive system includes: a vehicle mechanical connection structure, a circuit structure, a self-circulating cooling system, and a cooling drive system; the control method includes: The vehicle's speed is obtained, and the vehicle's operating condition is determined based on the vehicle's speed; wherein, the vehicle's operating condition includes idling operating condition and running operating condition. If the vehicle is in a parking idling state, the first clutch in the vehicle's mechanical connection structure is disconnected, and the charge state of the high-voltage battery in the vehicle is obtained. When the charge state of the high-voltage battery is less than a first target charge state, at least one of the fuel cell stack and the drive motor is controlled to charge the high-voltage battery. The first clutch is located between the transmission in the vehicle's mechanical connection structure and the drive motor in the circuit structure. If the vehicle is in operation, the coolant temperature of the fuel cell stack is acquired, and the self-circulating cooling system or the cooling drive system is switched to cool the coolant of the fuel cell stack according to the coolant temperature; and when the cooling drive system cools the coolant of the fuel cell stack, the output state of the mechanical torque of the cooling drive system is controlled according to the outlet pressure of the working fluid circulation pump in the cooling drive system; wherein, the cooling drive system is also used to provide mechanical torque to the drive motor.

2. The control method for a fuel cell vehicle drive system according to claim 1, characterized in that, Switching between a self-circulating cooling system and a cooling drive system to cool the coolant in the fuel cell stack based on the coolant temperature includes: The temperature of the coolant is compared with a first preset temperature and a second preset temperature; If the coolant temperature is lower than the first preset temperature, the self-circulating cooling system is controlled to cool the coolant. If the coolant temperature is greater than the second preset temperature, the cooling drive system is controlled to cool the coolant.

3. The control method for a fuel cell vehicle drive system according to claim 2, characterized in that, The self-circulating cooling system includes: a fuel cell stack, a cooling working fluid pump, a three-way valve, and a heat exchanger; the cooling drive system includes: the heat exchanger, the working fluid circulation pump, a control valve, an expander, and a condenser; the cooling working fluid outlet of the fuel cell stack is connected to the inlet of the cooling working fluid pump; the outlet of the cooling working fluid pump is connected to the first end of the three-way valve; the second end of the three-way valve is connected to the first inlet of the heat exchanger; the third end of the three-way valve is connected to the cooling working fluid outlet of the fuel cell stack; the first outlet of the heat exchanger is connected to the cooling working fluid outlet of the fuel cell stack; the second inlet of the heat exchanger is connected to the outlet of the working fluid circulation pump; the second outlet of the heat exchanger is connected to the first end of the control valve, and the second end of the control valve is connected to the inlet of the expander; the third end of the control valve and the outlet of the expander are connected to the inlet of the condenser, and the outlet of the condenser is connected to the inlet of the working fluid circulation pump; Controlling the self-circulating cooling system to cool the coolant includes: The first and third ends of the three-way valve are controlled to be connected so that the coolant flows through the first and third ends of the three-way valve to the coolant inlet end of the fuel stack after passing through the cooling working fluid pump. Controlling the cooling drive system to cool the coolant includes: The first and second ends of the three-way valve are connected to allow the coolant to enter the heat exchanger through the cooling medium pump, exchange heat with the cooling medium in the heat exchanger, and flow to the cooling medium inlet of the fuel cell stack through the first outlet end of the heat exchanger.

4. The control method for a fuel cell vehicle drive system according to claim 3, characterized in that, The mechanical torque output state of the cooling drive system is controlled based on the outlet pressure of the working fluid circulation pump in the cooling drive system, including: Obtain the outlet pressure of the working fluid circulation pump in the cooling drive system, and compare the outlet pressure of the working fluid circulation pump with a first preset pressure and a second preset pressure. If the outlet pressure of the working fluid circulation pump is less than the first preset pressure, the first and third ends of the control valve in the cooling drive system are opened to control the cooling drive system to stop outputting the mechanical torque to the drive motor. If the outlet pressure of the working fluid circulation pump is greater than the second preset pressure, the first and second ends of the control valve in the cooling drive system are opened to control the cooling drive system to output the mechanical torque to the drive motor.

5. The control method for a fuel cell vehicle drive system according to claim 1, characterized in that, When the state of charge of the high-voltage battery is less than the first target state of charge, controlling at least one of the fuel cell stack and the drive motor to charge the high-voltage battery includes: The control cooling drive system provides mechanical torque to the drive motor, so that the mechanical energy generated by the drive motor based on the mechanical torque is converted into electrical energy to charge the high-voltage battery; and the control of the fuel cell stack to charge the high-voltage battery.

6. The control method for a fuel cell vehicle drive system according to claim 5, characterized in that, Also includes: When the charge state of the high-voltage battery is greater than the second target charge state, the fuel cell stack is controlled to stop charging the high-voltage battery, while the drive motor continues to charge the high-voltage battery.

7. The control method for a fuel cell vehicle drive system according to claim 6, characterized in that, The charging power of the fuel cell stack is determined based on the charge range of the high-voltage battery; the charge of the high-voltage battery includes multiple charge ranges, and each charge range corresponds to a charging power.

8. The control method for a fuel cell vehicle drive system according to claim 4, characterized in that, Controlling the cooling drive system to output the mechanical torque to the drive motor includes: The rotational speeds of the expander and the drive motor are obtained. When the difference between the rotational speed of the drive motor and the rotational speed of the expander is less than a first preset value, the driving disc and the driven disc of the second clutch are controlled to engage. The driving disc is fixedly connected to the mechanical output shaft of the expander, and the driven disc is fixedly connected to the drive shaft of the drive motor.

9. A control device for a fuel cell vehicle drive system, characterized in that, include: The vehicle status determination module is used to obtain the vehicle's driving speed and determine the vehicle's operating condition based on the vehicle's driving speed; wherein, the vehicle's operating condition includes a parking idling condition and a running condition. A high-voltage battery charging module is used to control the disconnection of a first clutch in the vehicle's mechanical connection structure and obtain the charge state of the high-voltage battery in the vehicle when the vehicle is in a parking idling condition, and to control at least one of a fuel cell stack and a drive motor to charge the high-voltage battery when the charge state of the high-voltage battery is less than a first target charge state; wherein the first clutch is located between the transmission in the vehicle's mechanical connection structure and the drive motor in the circuit structure. The cooling module is used to acquire the coolant temperature of the fuel cell stack when the vehicle is in operation, and switch between a self-circulating cooling system and a cooling drive system to cool the coolant of the fuel cell stack according to the coolant temperature; and when the cooling drive system cools the coolant of the fuel cell stack, it controls the output state of the mechanical torque of the cooling drive system according to the outlet pressure of the working fluid circulation pump in the cooling drive system; wherein, the cooling drive system is also used to provide mechanical torque to the drive motor.

10. A fuel cell vehicle drive system, characterized in that, include: The circuit structure is used to convert electrical energy into driving force for the entire vehicle; A self-circulating cooling system is used to cool the fuel stack when the coolant temperature is lower than a first preset temperature. A cooling drive system is used to cool the fuel stack when the coolant temperature of the fuel stack is greater than a second preset temperature, and to provide power to the drive motor in the mechanical connection structure of the vehicle. The vehicle mechanical connection structure includes a first clutch, a drive motor, and a transmission, wherein the first clutch is located between the transmission in the vehicle mechanical connection structure and the drive motor in the circuit structure. The vehicle mechanical connection structure is used to convert the power generated in the cooling drive system and the circuit structure into the driving force of the vehicle.

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