A thermal management system and control method for waste heat utilization via electric drive

Abstract

This invention discloses a thermal management system for utilizing waste heat from an electric drive system. The vehicle's thermal cycle system includes a heat pump system, a battery system, and an electric drive system. The output port of the heat pump system is connected to the input port of the electric drive system. The output port of the electric drive system is connected to the input port of a one-in-two-out three-way valve. One output port of the one-in-two-out three-way valve is connected via a three-way valve to the input ports of the heat pump system and the battery system. The other output port of the one-in-two-out three-way valve and the output port of the battery system are connected to the two input ports of a two-in-one-out three-way valve. The output port of the two-in-one-out three-way valve is connected to the input port of the electric drive system. This invention uses a combined simulation model based on a vehicle drivetrain model, a thermal management model, and a control strategy model, and correlates it with the usage scenario. Multiple temperature setpoints are set using DOE (Design of Effect) multi-parameter settings. Optimization analyses are performed on drivetrain energy loss, thermal management accessory energy consumption, and battery energy loss. Finally, the temperature setpoints are determined according to the principle of energy consumption optimization, and real-time control is implemented.

Description

Technical Field

[0001] This invention relates to the automotive field (including pure electric vehicles), and specifically to a thermal management system and waste heat utilization control method for electric drive waste heat utilization. Background Technology

[0002] With the widespread adoption of electric vehicles, the issue of low-temperature range has become one of the core pain points for customers. Reducing the overall energy consumption of the vehicle at low temperatures and increasing the battery discharge energy have become top priorities. In winter, the main heat source for vehicle heating comes from PTC electric heaters and heat pump systems. Some of this heat comes from waste heat generated by electric drive. For example, the patent publication CN110254175A, published on September 20, 2019, entitled "A Waste Heat Recovery Heat Pump Thermal Management Device for New Energy Vehicles," discloses a waste heat recovery heat pump thermal management device including an electric compressor. One end of the electric compressor is connected to one end of a first three-way valve, and the other end of the electric compressor is connected to a gas-liquid separator. The other end of the first three-way valve is connected to one end of an outdoor heat exchanger. An evaporator and a plate heat exchanger are connected in parallel between the outdoor heat exchanger and the gas-liquid separator. The evaporator is connected in series with a thermal expansion valve and a third two-way valve. The plate heat exchanger is connected in series with a first electronic expansion valve. A second electronic expansion valve and a first two-way valve are connected in parallel on the pipeline between the outdoor heat exchanger and the first electronic expansion valve.

[0003] The utilization of this energy in real vehicles is quite subjective, and it is difficult to achieve optimal utilization of waste heat. Specifically, if the waste heat is used for battery heating or heat pump heating too early, the electric drive itself will have a low temperature and excessive self-loss. If it is always stored in its own heat, it will lead to energy waste, and the battery temperature will be relatively low, resulting in increased battery loss and reduced battery discharge capacity. In general, it is the opposite of what is expected. Summary of the Invention

[0004] The technical problem to be solved by this invention is to realize a control system and method for utilizing waste heat from electric drives. Based on a combined simulation model of the whole vehicle drive system model, thermal management thermal model and control strategy model, and in conjunction with the usage scenario, the energy loss of the drive system, the energy consumption of thermal management accessories and the energy loss of the battery are optimized in real time.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a thermal management system with waste heat utilization in electric drive, wherein the vehicle's thermal cycle system includes a heat pump system, a battery system, and an electric drive system, the output port of the heat pump system is connected to the input port of the electric drive system, the output port of the electric drive system is connected to the input port of a one-in-two-out three-way valve, one output port of the one-in-two-out three-way valve is connected via a three-way valve to the input port of the heat pump system and the input port of the battery system, the other output port of the one-in-two-out three-way valve and the output port of the battery system are connected to the two input ports of a two-in-one-out three-way valve, and the output port of the two-in-one-out three-way valve is connected to the input port of the electric drive system.

[0006] The output port of the two-in-one-out three-way valve is connected to the pipeline between the heat pump system and the electric drive system through the three-way valve. The heat pump system, battery system, electric drive system, one-in-two-out three-way valve and two-in-one-out three-way valve are coordinated and controlled by the vehicle control unit, thermal management unit and electric drive control unit.

[0007] The electric drive system, the one-in-two-out three-way valve, and the two-in-one-out three-way valve form a circulation loop, which constitutes the electric drive's own hot water storage loop.

[0008] The battery system, the one-in-two-out three-way valve, the electric drive system, and the two-in-one-out three-way valve form a circulation loop, constituting the battery heating water circuit;

[0009] The heat pump system, electric drive system, and one inlet and two outlet three-way valve form a circulation loop, constituting the heat pump water heating circuit.

[0010] A waste heat utilization control method for a thermal management system with electric drive for waste heat utilization:

[0011] In the initial state, the electric drive operates its own hot water storage circuit;

[0012] When condition 1 is met, the battery heating water circuit is activated;

[0013] Condition 1: The water temperature Tm of the electric drive system exceeds the set temperature threshold A, and the battery temperature Tb is less than the set temperature threshold B.

[0014] When the battery heating water circuit is executed, if condition 2 is met, the electric drive's own hot water storage circuit will be executed.

[0015] Condition 2: The difference between Tm and Tb is less than the temperature setting threshold D.

[0016] If the battery temperature continues to rise, the electric drive water circuit temperature gradually decreases until condition 2 is met. At this point, the electric drive switches to its own heat storage state and stops heating the battery. When condition 1 is met again, the battery is heated again, or when condition 3 is met, the heat pump system is heated. See [link to relevant documentation]. Figure 6 At this time, the temperature of the electric drive water circuit gradually decreases until condition 4 is met, at which point the electric drive switches to its own heat storage state.

[0017] When condition 3 is met, the heat pump water heating circuit is activated;

[0018] Condition 3: The electric drive water circuit temperature Tm exceeds the set temperature threshold C, and the battery temperature Tb is greater than the set temperature threshold B.

[0019] The waste heat utilization control method for electric drive waste heat utilization, when executing the heat pump heating water circuit, if condition 4 is met, then the electric drive self-storage hot water circuit is executed.

[0020] Condition 4: Tm is less than the set temperature threshold E.

[0021] A joint simulation model is established based on the vehicle drive system model, thermal management model, and control strategy model. Based on the joint simulation model, DOE multi-parameter settings are performed on the set temperature threshold. Following the principle of energy consumption optimization, set temperature thresholds A, B, C, D, and E are obtained respectively.

[0022] The present invention provides a control system and method for utilizing waste heat from electric drives. Based on a combined simulation model, the system combines a vehicle drivetrain model, a thermal management model, and a control strategy model. It is also associated with the usage scenario. Multiple temperature thresholds are set using DOE (Domain of Effect) multi-parameter settings. The system performs optimization analysis on drivetrain energy loss, thermal management accessory energy consumption, and battery energy loss. Finally, the temperature thresholds are determined according to the principle of energy consumption optimization, and real-time control is performed. Attached Figure Description

[0023] The following is a brief explanation of the content represented by each figure in this specification:

[0024] Figure 1 This is a schematic diagram of the co-simulation model of the present invention;

[0025] Figure 2 This is a schematic diagram of the control method for utilizing waste heat from electric drives according to the present invention;

[0026] Figure 3 This is a schematic diagram of the electric drive waste heat utilization water circuit of the thermal management system involved in this invention;

[0027] Figure 4 This is a schematic diagram of the electric drive waste heat utilization - electric drive self-storage hot water circuit of the present invention;

[0028] Figure 5 This is a schematic diagram of the electric drive waste heat utilization-battery water heating circuit of the present invention;

[0029] Figure 6 This is a schematic diagram of the electric drive waste heat utilization-heat pump water heating circuit of the present invention. Detailed Implementation

[0030] The following description, with reference to the accompanying drawings, details the specific implementation of the present invention, including the shape and structure of each component, the relative positions and connections between the parts, the function and working principle of each part, the manufacturing process, and the operation and use methods, to help those skilled in the art to have a more complete, accurate, and in-depth understanding of the inventive concept and technical solution of the present invention.

[0031] This invention is a control system and method for utilizing waste heat from electric drives. It combines a vehicle drivetrain model, a thermal management model, and a control strategy model into a joint simulation model, and associates it with the usage scenario. Multiple temperature set thresholds are set using DOE (Design of Effect) multi-parameter settings. Optimization analysis is performed on drivetrain energy loss, thermal management accessory energy consumption, and battery energy loss. Finally, the temperature set threshold is determined according to the principle of energy consumption optimization, and real-time control is performed.

[0032] like Figure 3 The thermal management system for utilizing waste heat from electric drive is shown in the schematic diagram. The thermal management system for utilizing waste heat from electric drive has a new circulation loop based on the existing thermal circulation loop of the heat pump system, battery system, and electric drive system. Two electronically controlled valves are added for coordinated control. The two electronically controlled valves are a one-inlet-two-outlet three-way valve and a two-inlet-one-outlet three-way valve. The thermal circulation loops of the heat pump system, battery system, and electric drive system are all equipped with an inlet (water inlet) and an outlet (water outlet).

[0033] The connection method is as follows:

[0034] One output port of the one-in-two-out three-way valve is connected to the heat pump system and the battery system's heat circulation system input port (water inlet) respectively. Since it connects to the input ports of two systems at the same time, it can be connected through a three-way valve. That is, the three outlets of the three-way valve are connected to the heat pump system, the battery system's heat circulation system input port (water inlet) respectively through pipelines, and one output port of the one-in-two-out three-way valve.

[0035] The other output port of the one-in-two-out three-way valve is connected to one input port of the two-in-one-out three-way valve through a pipeline. The output port (water outlet) of the battery system's thermal circulation system is connected to the other input port of the two-in-one-out three-way valve. The output port (water outlet) of the electric drive system's thermal circulation system is connected to the input port of the one-in-two-out three-way valve through a pipeline.

[0036] The inlet (water inlet) of the electric drive system's thermal circulation system is connected to the outlet of the two-inlet-one-outlet three-way valve and the outlet (water outlet) of the heat pump system's thermal circulation system via pipelines. Therefore, it can be connected through a three-way valve, that is, the three outlets of the three-way valve are connected to the outlet (water outlet) of the heat pump system's thermal circulation system, the outlet of the two-inlet-one-outlet three-way valve, and the inlet (water inlet) of the electric drive system's thermal circulation system via pipelines.

[0037] A one-in-two-out three-way valve is electrically controlled to connect one of its output ports to its input port, and a two-in-one-out three-way valve is electrically controlled to connect one of its input ports to its output port. The specific choice depends on the pre-set control logic.

[0038] When the one-in-two-out three-way valve controls the electric drive system to be connected to the two-in-one-out three-way valve, and simultaneously the two-in-one-out three-way valve controls the one-in-two-out three-way valve to be connected to the electric drive system, then the electric drive system, the one-in-two-out three-way valve, and the two-in-one-out three-way valve form a circulation loop, constituting the electric drive's own hot water storage loop. Figure 4 As shown, the coolant flowing out of the electric drive system returns to the electric drive system through a one-in-two-out three-way valve and a two-in-one-out three-way valve, forming a complete circulation loop;

[0039] When a one-in-two-out three-way valve controls the connection between the battery system and the electric drive system, and simultaneously a two-in-one-out three-way valve controls the connection between the battery system and the electric drive system, then the battery system, the one-in-two-out three-way valve, the electric drive system, and the two-in-one-out three-way valve form a circulation loop, constituting the battery heating water circuit. Figure 5 As shown, the coolant flowing out of the electric drive system flows to the battery system through a three-way valve with one inlet and two outlets, and the coolant flowing out of the battery system flows to the electric drive system through a three-way valve with two inlets and one outlet, forming a complete circulation loop.

[0040] When the one-in-two-out three-way valve controls the connection between the heat pump system and the electric drive system, the two-in-one-out three-way valve does not enter the circulation loop. The heat pump system, the electric drive system, and the one-in-two-out three-way valve form a circulation loop, constituting the heat pump heating water circuit. Figure 6 As shown, the coolant flowing out of the electric drive system flows to the heat pump system through a three-way valve with one inlet and two outlets, and the coolant flowing out of the heat pump system flows back to the electric drive system, forming a complete circulation loop.

[0041] Based on the aforementioned thermal management system for utilizing waste heat from electric drives, the control method for this utilization is a simultaneous simulation model that combines the vehicle's powertrain model, thermal management model, and control strategy model. This model is then used in conjunction with usage scenarios to optimize real-time powertrain energy loss, thermal management accessory energy consumption, and battery energy loss. The required hardware components include the vehicle control unit, thermal management unit, and electric drive control unit.

[0042] The vehicle control unit reads basic signal information such as vehicle speed, ambient temperature, and passenger compartment temperature.

[0043] The thermal management unit reads basic signal information such as battery water ingress temperature.

[0044] The electric drive control unit reads basic signal information, such as the electric drive stator temperature.

[0045] By associating usage scenarios (as analysis boundaries and target inputs), basic signal information is read through the vehicle control unit, thermal management unit, and electric drive control unit: vehicle speed, ambient temperature, passenger compartment temperature, electric drive water ingress temperature, electric drive stator temperature, battery water ingress temperature, and other vehicle and thermal management signals. For example... Figure 1 As shown in the established simulation model, the vehicle control unit serves as the control core of this system. It connects to and outputs drive signals to the one-in-two-out three-way valve and the two-in-one-out three-way valve. The thermal management unit connects to and coordinates the control of the heat pump system and the battery system. The electric drive control unit connects to and coordinates the control of the electric drive system. The vehicle control unit obtains information from the thermal management unit and the electric drive control unit through the CAN network and performs overall coordinated control. By controlling the one-in-two-out three-way valve and the two-in-one-out three-way valve, the waste heat utilization of the electric drive in the thermal management system is realized.

[0046] The establishment of the joint simulation model involves real-time acquisition of ambient temperature, passenger compartment temperature, target passenger compartment temperature, vehicle speed, and gradient. The acquired data is then input into the powertrain physical model and the thermal management physical model, which are pre-designed data models for each vehicle model to acquire relevant theoretical data. The acquired signals are used to obtain the vehicle's required power based on the powertrain physical model, and the acquired signals are used to obtain the power consumption of thermal management accessories based on the thermal management physical model.

[0047] The required power for the entire vehicle includes: electric drive physical model, battery physical model, and battery physical model.

[0048] Based on settings:

[0049] Threshold A1 / A2……

[0050] Threshold C1 / C2...

[0051] Threshold D1 / D2...

[0052] The electric drive physical model yields the following energy losses: Q1 / Q2...

[0053] The battery physics model yields the following: energy loss of the battery system W1 / W2...

[0054] The battery physics model yields: battery system discharge capacity E1 / E2...

[0055] The power consumption of the thermal management accessory is based on thresholds B1 / B2... to obtain the energy loss P1 / P2 of the thermal management system...

[0056] Because this system uses real-time vehicle data to obtain current vehicle status information, the total vehicle power demand and thermal management accessory power consumption change with the vehicle status, making the utilization of electric drive waste heat in the thermal management system more reliable and reasonable.

[0057] Finally, based on the energy loss of the electric drive system, the energy loss of the battery system, the battery system discharge capacity, and the energy loss of the thermal management system, the Q+W+P+E parameters are optimized to determine the A / B / C thresholds. The temperature setting thresholds A / B / C / D / E are then set using multiple parameters (DOE). Optimization analyses are performed on the energy loss of the transmission system, the energy consumption of thermal management accessories, and the energy loss of the battery.

[0058] Following the principle of energy consumption optimization, that is, finding the best among Q+W+P+E, the corresponding temperature setting threshold values ​​A / B / C / D / E are determined;

[0059] Then, according to the control strategy logic, the initial state is that the electric drive itself stores heat. If the electric drive water circuit temperature Tm exceeds the temperature setting threshold A and the battery temperature Tb is less than the temperature setting threshold B, the waste heat of the electric drive is used to heat the battery. When the heating capacity is small, that is, when the difference between Tm and Tb is less than the temperature setting threshold D, the battery heating is stopped and the electric drive enters the electric drive itself stores heat. If the electric drive heating capacity is sufficient and the battery does not need to be heated, that is, when the electric drive water circuit temperature Tm exceeds the temperature setting threshold C and the battery temperature Tb is greater than the temperature setting threshold B, the waste heat of the electric drive is used to heat the heat pump. When the electric drive temperature is low, that is, when Tm is less than the set temperature threshold E, the heat pump heating is stopped and the electric drive enters the electric drive itself stores heat.

[0060] Furthermore, by relating the application scenarios, basic signal information is read through the vehicle control unit, thermal management unit, and electric drive control unit: vehicle speed, ambient temperature, passenger compartment temperature, electric drive water inlet temperature, electric drive stator temperature, battery water inlet temperature, and other vehicle and thermal management signals. Based on the established joint simulation model, DOE multi-parameter settings are performed on the temperature setting thresholds A / B / C / D / E to conduct optimization analysis on transmission system energy loss, thermal management accessory energy consumption, and battery energy loss.

[0061] The specific strategy logic is as follows:

[0062] In the initial state, that is, when the vehicle starts, the electric drive's own hot water storage circuit is executed;

[0063] Set the following conditions:

[0064] Condition 1: If the electric drive water circuit temperature Tm exceeds the temperature setting threshold A and the battery temperature Tb is less than the temperature setting threshold B, the waste heat of the electric drive will be used to heat the battery.

[0065] Condition 2: When the heating capacity is low, that is, when the difference between Tm and Tb is less than the temperature setting threshold D, the battery heating is stopped and the electric drive enters its own heat storage state.

[0066] Condition 3: If the electric drive heating capacity is sufficient and the battery does not need to be heated, that is, when the electric drive water circuit temperature Tm exceeds the temperature setting threshold C and the battery temperature Tb is greater than the temperature setting threshold B, the waste heat of the electric drive is used to heat the heat pump.

[0067] Condition 4: When the electric drive temperature is low, i.e., Tm is less than the set temperature threshold E, the heat pump heating is stopped and the electric drive enters its own heat storage state.

[0068] When condition 1 is met, the electric-driven water circuit switches to the battery-heated water circuit. Figure 5 As shown, the battery temperature continues to rise, while the temperature of the electric drive water circuit gradually decreases.

[0069] When condition 2 is met, the electric drive switches to its own hot water storage circuit and stops heating the battery. When condition 1 is met again, the battery is heated again.

[0070] When condition 3 is met, the heat pump system is heated, and the electric drive switches to the heat pump heating water circuit. See below. Figure 6 At this time, the temperature of the electric drive water circuit gradually decreases;

[0071] When the heat pump is in the water heating circuit state, and condition 4 is met, the electric drive switches to its own water storage circuit.

[0072] The present invention has been described above by way of example with reference to the accompanying drawings. Obviously, the specific implementation of the present invention is not limited to the above-described manner. Any non-substantial improvements made using the inventive concept and technical solution of the present invention, or the direct application of the inventive concept and technical solution of the present invention to other occasions without modification, are all within the protection scope of the present invention.

Claims

1. A thermal management system for utilizing waste heat from electric drive, wherein the vehicle's thermal cycle system includes a heat pump system, a battery system, and an electric drive system, characterized in that: The output port of the heat pump system is connected to the input port of the electric drive system. The output port of the electric drive system is connected to the input port of the one-in-two-out three-way valve. One output port of the one-in-two-out three-way valve is connected to the input port of the heat pump system and the input port of the battery system via a three-way valve. The other output port of the one-in-two-out three-way valve and the output port of the battery system are connected to the two input ports of the two-in-one-out three-way valve. The output port of the two-in-one-out three-way valve is connected to the input port of the electric drive system. The output port of the two-in-one-out three-way valve is connected to the pipeline between the heat pump system and the electric drive system through the three-way valve. The heat pump system, battery system, electric drive system, one-in-two-out three-way valve and two-in-one-out three-way valve are coordinated and controlled by the vehicle control unit, thermal management unit and electric drive control unit.

2. The thermal management system for utilizing waste heat via electric drive according to claim 1, characterized in that: The electric drive system, the one-in-two-out three-way valve, and the two-in-one-out three-way valve form a circulation loop, which constitutes the electric drive's own hot water storage loop. The battery system, the one-in-two-out three-way valve, the electric drive system, and the two-in-one-out three-way valve form a circulation loop, constituting the battery heating water circuit; The heat pump system, electric drive system, and one inlet and two outlet three-way valve form a circulation loop, constituting the heat pump water heating circuit.

3. A waste heat utilization control method for a thermal management system with electric drive for waste heat utilization, characterized in that: In the initial state, the electric drive operates its own hot water storage circuit; When condition 1 is met, the battery heating water circuit is activated; Condition 1: The water temperature Tm of the electric drive system exceeds the set temperature threshold A, and the battery temperature Tb is less than the set temperature threshold B. When the battery heating water circuit is executed, if condition 2 is met, the electric drive's own hot water storage circuit will be executed. Condition 2: The difference between Tm and Tb is less than the set temperature threshold D; If the battery temperature continues to rise, the electric drive water circuit temperature gradually decreases until condition 2 is met. At this time, the electric drive switches to its own heat storage state and stops heating the battery. When condition 1 is met again, the battery is heated again, or when condition 3 is met, the heat pump system is heated. See Figure 6. At this time, the electric drive water circuit temperature gradually decreases until condition 4 is met. At this time, the electric drive switches to its own heat storage state. When condition 3 is met, the heat pump water heating circuit is activated; Condition 3: The electric drive water circuit temperature Tm exceeds the set temperature threshold C, and the battery temperature Tb is greater than the set temperature threshold B. When the heat pump heating water circuit is executed, if condition 4 is met, the electric drive self-storage hot water circuit will be executed. Condition 4: Tm is less than the set temperature threshold E; A joint simulation model is established based on the vehicle drive system model, thermal management model, and control strategy model. Based on the joint simulation model, DOE multi-parameter settings are performed on the set temperature threshold. Following the principle of energy consumption optimization, set temperature thresholds A, B, C, D, and E are obtained respectively.

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