A new energy vehicle thermal management system and method

Abstract

The application discloses a new energy vehicle thermal management system and method, relates to the technical field of new energy vehicle thermal management, and comprises the following steps: analyzing a thermal time constant, and calculating a target temperature rise rate; calculating a direct-axis current instruction amplitude, and obtaining a heat pump carrying capacity margin; taking the heat pump carrying capacity margin as a dynamic adjustment factor generated by the direct-axis current instruction amplitude, and executing a motor heat production power self-adaptive constraint strategy, so that the direct-axis current instruction amplitude is finally obtained; inputting the direct-axis current instruction amplitude into a motor loss model, so that the motor loss model outputs real-time heat production power; calculating a maximum allowable heat production power under a current state; analyzing a heating quantity attenuation gradient for adjusting the target temperature rise rate into a corrected temperature rise rate, obtaining a heat source power target, calculating a target rotating speed required by a compressor according to the heat source power target, and calculating the heat pump carrying capacity margin.

Description

Technical Field

[0001] This application relates to the field of thermal management technology for new energy vehicles, and in particular to a thermal management system and method for new energy vehicles. Background Technology

[0002] Heating the passenger compartment in low-temperature environments is a core issue affecting the vehicle's energy consumption and driving range. Currently, most new energy vehicles use high-voltage PTC or HVH heating systems, which are simple to control but have significant drawbacks: the heater encroaches on the passenger compartment space, the energy efficiency ratio is always less than 1 under low-temperature conditions, and the high-voltage system increases insulation protection costs and failure risks.

[0003] Some models are equipped with heat pump air conditioning systems to improve energy efficiency, with a heating efficiency ratio of 2 to 4, significantly reducing electricity consumption. However, when the ambient temperature drops below -15°C, the heat pump's ability to absorb heat from the ambient air decreases sharply, and most systems still need to retain PTC as an auxiliary heat source, not truly eliminating their dependence on resistance heating elements.

[0004] To address this, the industry has proposed an extremely simplified architecture that completely eliminates PTC and uses the waste heat of the motor as the sole auxiliary heat source. However, how to ensure heating performance across all scenarios without diminishing the heat supply has become a pressing technical challenge. In light of this, we propose a thermal management system and method for new energy vehicles. Summary of the Invention

[0005] To address the above problems, this application provides a thermal management system for new energy vehicles, comprising: The heat generation command module analyzes the thermal time constant and calculates the target temperature rise rate; The motor heat and capacity feedback module calculates the direct-axis current command amplitude and obtains the heat pump transport capacity margin. It uses the heat pump transport capacity margin as a dynamic adjustment factor for generating the direct-axis current command amplitude and executes an adaptive constraint strategy for motor heat generation power to finally obtain the direct-axis current command amplitude. Input the direct-axis current command amplitude to the motor loss model, and the motor loss model outputs the real-time heat generation power; calculate the maximum allowable heat generation power that the permanent magnet can withstand under the current state without causing irreversible demagnetization; The demagnetization safety power margin is calculated by real-time heat generation power and maximum allowable heat generation power. Then, the heat generation attenuation gradient used to adjust the target temperature rise rate to the corrected temperature rise rate is obtained by analysis. The motor heat and capacity feedback module is executed again until the thermal stability control state is reached. The heat transport and margin constraint module obtains the heat source power target, calculates the target speed that the compressor needs to reach based on the heat source power target, and calculates the heat pump transport capacity margin.

[0006] Preferably, the heat generation command generation module includes a system thermal inertia online identification unit and a target temperature rise rate decision unit, wherein: The system's online thermal inertia identification unit receives signals from the compressor speed sensor and the condensing pressure sensor on the front-end module side, identifies the time delay of the condensing pressure response curve relative to the step change in compressor speed, thereby continuously monitoring the lag relationship between the condensing pressure build-up rate and the compressor speed change, and estimating a thermal time constant that reflects the overall thermal response lag. The thermal time constant is ;in, For the preset ratio threshold, This represents the initial moment when the compressor speed undergoes a step change. This represents the initial steady-state value of the condensing pressure before the speed step. This is the new steady-state value that the condensing pressure should reach after a speed jump; The target temperature rise rate decision unit receives the deviation signal between the actual temperature and the target temperature fed back by the temperature sensor arranged in the crew compartment; it uses the thermal time constant output by the system thermal inertia online identification unit as the key factor for calculation, and calculates the target temperature rise rate based on the functional relationship that automatically decays as the thermal time constant increases.

[0007] Preferably, the motor heat and capacity feedback module includes an active loss heat generation control unit, a real-time available heat capacity estimation unit, and a heat capacity attenuation trend calculation unit, wherein: The active loss heat generation control unit receives the target temperature rise rate from the target temperature rise rate decision unit and converts the target temperature rise rate into a target value of total heating power required to control the motor; the target value of the total heating power is converted into the amplitude of the direct-axis current command. Obtain the heat pump transport capacity margin, use the heat pump transport capacity margin as a constraint correction factor for the direct-axis current command amplitude, and execute the following adaptive constraint strategy for motor heat generation power; to obtain the final direct-axis current command amplitude. The real-time available heating capacity estimation unit acquires the motor loss model and uses it to estimate the current real-time heat generation power. In parallel, it continuously monitors the permanent magnet temperature and calculates the maximum allowable heat generation power that the permanent magnet can withstand in the current state without causing irreversible demagnetization, based on a strict demagnetization protection boundary function. The minimum value between the real-time heat generation power and the maximum allowable heat generation power is defined as the current maximum available heating capacity. The heating capacity attenuation trend calculation unit calculates the heating capacity attenuation gradient based on the maximum available heating capacity in the real-time available heating capacity estimation unit, and adjusts the target temperature rise rate to a corrected temperature rise rate based on the heating capacity attenuation gradient, based on the target temperature rise rate in the target temperature rise rate decision unit.

[0008] Preferably, the adaptive constraint strategy for the heat generation power of the motor is as follows: Set a tightening threshold; when the heat pump carrying capacity margin is lower than the tightening threshold, actively apply an attenuation factor above the direct-axis current command amplitude corresponding to the target temperature rise rate; When the heat pump transport capacity margin is greater than or equal to the sufficient threshold, the attenuation factor decreases proportionally with the heat pump transport capacity margin when an attenuation factor is applied. The attenuation factor is as follows: ; In the formula For heat pump transport capacity margin, This is the minimum attenuation factor limit.

[0009] Preferably, the tightening threshold is based on the current maximum available heating capacity output by the real-time available heating capacity estimation unit, and is superimposed with the heating capacity decay gradient from the heating capacity decay trend calculation unit, and then the margin released due to heating demand is subtracted to obtain the tightening threshold, as follows: ; in: The current maximum available heating capacity is obtained by taking the smaller of the estimated value from the motor loss model and the demagnetization protection boundary value from the real-time available heating capacity estimation unit. The heating capacity attenuation gradient is obtained by the real-time available heating capacity estimation unit through continuous monitoring of the narrowing rate of the difference between the estimated value of the motor loss model and the demagnetization protection boundary value. The target temperature rise rate in the target temperature rise rate decision unit; : Maximum permissible temperature rise rate of the motor.

[0010] Preferably, the heating capacity attenuation gradient is as follows: At the current sampling time Compared with the previous sampling time Calculate the difference between the real-time heat generation power output by the motor loss model in the real-time available heating capacity estimation unit and the maximum allowable heat generation power; analyze and obtain the demagnetization safety power margin: ; ; in and These are the demagnetization safety power margins for the current time and the previous time, respectively. , These are the estimated values ​​of the motor loss model and the demagnetization protection boundary values, respectively; specifically, the estimated values ​​of the motor loss model and the demagnetization protection boundary values ​​correspond to the real-time heat generation power and the maximum allowable heat generation power in the real-time available heat generation estimation unit. The heating capacity attenuation gradient is obtained by dividing the periodic change of the demagnetization safety power margin by the sampling time interval of the corresponding thermal state parameters of the heat pump system.

[0011] Preferably, the corrected temperature rise rate is as follows: ; in: For the heat output attenuation gradient, For attenuation compensation gain coefficient, The target temperature rise rate is the target temperature rise rate in the target temperature rise rate decision unit.

[0012] Preferably, the heat transport and margin constraint module includes a heat source power comparison and arbitration unit and a compressor speed constraint adjustment unit; The heat source power comparison and arbitration unit receives the current maximum available heat capacity from the real-time available heat capacity estimation unit, and calculates the theoretical heating power required to meet the current comfort requirements based on the target temperature of the occupant cabin and the ambient temperature; it compares the current maximum available heat capacity and the theoretical heating power, and selects the smaller one as the actual available heat source power target; The compressor speed constraint adjustment unit uses the heat source power target output by the heat source power comparison and arbitration unit as the power target, and calculates the target speed that the compressor needs to achieve by combining the real-time energy efficiency ratio under the current heat pump system operating conditions.

[0013] Preferably, the heat pump transport capacity margin in the active loss heat generation control unit is as follows: During the compressor speed regulation process, the compressor speed constraint adjustment unit continuously compares the current actual transport power with the current maximum available heating capacity to determine the heat pump transport capacity margin. ,in This represents the actual thermal power. The current maximum available heating capacity in the real-time available heating capacity estimation unit.

[0014] A thermal management method for new energy vehicles includes the following: Analyze the thermal time constant and calculate the target temperature rise rate; The direct-axis current command amplitude is calculated, and the heat pump transport capacity margin is obtained. The heat pump transport capacity margin is used as a dynamic adjustment factor for the generation of the direct-axis current command amplitude. The adaptive constraint strategy of motor heat generation power is executed, and finally the direct-axis current command amplitude is obtained. Input the direct-axis current command amplitude to the motor loss model, and the motor loss model outputs the real-time heat generation power; calculate the maximum allowable heat generation power that the permanent magnet can withstand under the current state without causing irreversible demagnetization; The demagnetization safety power margin is calculated by real-time heat generation power and maximum allowable heat generation power. Then, the heat generation attenuation gradient used to adjust the target temperature rise rate to the corrected temperature rise rate is obtained by analysis. The maximum allowable heat generation power is analyzed again until the thermal stability control state is reached. Obtain the target heat source power, calculate the target speed required for the compressor based on the target heat source power, and calculate the heat pump transport capacity margin.

[0015] Compared with existing technologies, this application has the following advantages: This invention addresses the extremely simplified architecture that completely eliminates the independent PTC heater, relying solely on the active heat loss of the motor combined with the heat pump cycle as the sole heating source. It constructs a dual-loop, cross-coupled, and interconnected control system for electricity and heat, encompassing three major modules: heat generation command generation, motor heat and capacity feedback, and heat transport and margin constraints. Through multi-dimensional dynamic matching and forward-looking correction, it solves three core problems in extremely cold scenarios without requiring additional heating hardware: temperature overshoot oscillation caused by thermal inertia lag, step disturbances caused by continuous heating demagnetization attenuation, and a vicious cycle of heat accumulation caused by transient operating condition imbalance. This achieves simultaneous improvement in heating comfort, system safety, and energy efficiency. Specifically... First, the thermal inertia online identification unit monitors the condensing pressure in real time to establish the lag relationship between the speed and the compressor speed. The thermal time constant, which reflects the overall thermal response lag of the system, is dynamically estimated. Then, the target temperature rise rate decision unit uses this thermal time constant as a key factor for calculation and constructs a mapping relationship that automatically decays as the thermal time constant increases to calculate the target temperature rise rate of the motor. This mechanism integrates the actual thermal response characteristics of the heat pump system into the heat generation command generation process in advance, so that the setting of the motor heating rate is always matched with the response speed that the heat pump can bear. It offsets the control deviation caused by the thermal inertia lag of the multi-stage heat exchange loop from the source of the control command, and avoids the overshoot and oscillation of the passenger cabin temperature that is easily caused by traditional temperature deviation feedback control under extremely cold conditions. Based on this, the active loss heat generation control unit and the compressor speed constraint adjustment unit form a two-way constraint closed loop of heat generation and transportation. On the one hand, the heat transportation and margin constraint module calculates the heat pump transportation capacity margin in real time and feeds it back to the motor side. The active loss heat generation control unit uses this margin as a dynamic correction factor for the direct-axis current command. When the margin is lower than the dynamic tightening threshold, the direct-axis current amplitude is smoothly reduced according to the margin narrowing ratio, thus constraining the actual heat generation rate of the motor within the range that the heat pump can currently absorb. On the other hand, the heat source power comparison and arbitration unit uses the current maximum available heating capacity fed back from the motor side in real time as a rigid upper limit, and takes the smaller of it and the theoretical heating power of the passenger compartment as the heat source power target of the heat pump. Then, the compressor speed constraint adjustment unit accurately calculates the compressor target speed based on this, so that the heat pump's heat generation... The transport capacity never exceeds the upper limit of the heat that the motor can safely provide at any given moment. At the same time, the tightening threshold is not a fixed constant, but is obtained by superimposing the dynamic bias of the heat attenuation gradient of the motor and combining it with the target temperature rise rate requirement, based on the current maximum available heat capacity. The constraint boundary can be dynamically adjusted according to the motor safety margin, attenuation trend and heating demand. Through the two-way linkage of adapting the heat generation side to the transport capacity and anchoring the heat generation upper limit on the transport side, the risks of heat accumulation in motor coolant, demagnetization of permanent magnets due to imbalance between heat generation and transport power caused by the tight coupling architecture without buffer heat storage are fundamentally eliminated. This avoids the control loop from falling into a vicious cycle of excessive heat generation - heat accumulation and temperature rise - limited heat capacity - narrow margin - relative heat generation, ensuring the stable operation of the system under transient operating condition switching. Furthermore, the heating capacity attenuation trend calculation unit and the target temperature rise rate decision unit form a forward-looking correction closed loop. The real-time available heating capacity estimation unit calculates in parallel the theoretical real-time heat generation power of the motor and the maximum allowable heat generation power corresponding to the demagnetization protection boundary, taking the minimum value as the current maximum available heating capacity. The heating capacity attenuation trend calculation unit calculates the heating capacity attenuation gradient by continuously monitoring the narrowing rate of the demagnetization safety power margin. This gradient can reflect the attenuation trend of heating capacity caused by the cumulative increase in permanent magnet temperature in advance. The target temperature rise rate decision unit adds a compensation amount that is inversely related to the attenuation gradient to the initial target temperature rise rate to obtain the corrected temperature rise rate. This allows the system to proactively and smoothly adjust the motor heat generation command during the attenuation trend manifestation stage without waiting for the permanent magnet to touch the demagnetization protection threshold and trigger hardware forced power limiting. This reduces the traditional demagnetization protection trigger time. The passive response control has been upgraded to an active adaptive control based on the changing trend of heat source capacity. In an architecture that completely eliminates the PTC heater and has no backup heat source buffer, it completely avoids the interruption of passenger compartment heating and drastic temperature fluctuations caused by a step drop in heat source power, ensuring temperature stability during continuous heating. Overall, this invention uses multi-loop cross-linking control between the three major modules to compensate for the control difficulties brought about by hardware simplification through the optimization of software control strategies. While completely eliminating the independent PTC heater and reducing hardware costs and layout space, it takes into account the heating comfort and system safety of all scenarios, including extreme cold start, steady-state continuous heating, and transient operating condition switching. Moreover, it relies on the heat pump to circulate and transfer the waste heat of the motor for heating throughout the process. Compared with PTC resistance heating, it significantly improves the heating energy efficiency under low-temperature conditions, effectively reduces the heating energy consumption of the whole vehicle, and extends the low-temperature driving range of new energy vehicles.

[0016] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the overall module of the present invention; Figure 2 This is a flowchart illustrating the working principle of the present invention; Figure 3This application provides an overall schematic diagram of a thermal management system for new energy vehicles. Figure 4 A schematic diagram illustrating the working principle of an integrated cooling mode that combines air conditioning refrigeration, motor control, and power battery. Figure 5 This is a schematic diagram of the working principle of the integrated cooling mode for motor, electronic control and power battery (i.e., only cooling the motor, electronic control and battery, without cooling the passenger compartment); Figure 6 This is a diagram illustrating the working principle of the air conditioning cooling mode (cooling only the passenger compartment). Figure 7 This diagram illustrates the working principle of the integrated rapid heating mode combining air conditioning heating, motor control, and power battery. Figure 8 This diagram illustrates the working principle of the integrated air conditioning heating, motor control, and power battery conventional heating mode. Figure 9 This is a schematic diagram illustrating the working principle of the rapid heating mode for power batteries. Figure 10 This is a schematic diagram illustrating the working principle of the conventional heating mode for power batteries (using only the waste heat of the motor for heating). Figure 11 This is a diagram illustrating the working principle of air conditioning heating (including defogging) mode.

[0019] The meanings of the labels in the diagram are as follows: 100. Heat generation command generation module; 110. Online thermal inertia identification unit; 120. Target temperature rise rate decision unit; 200. Motor heat and capacity feedback module; 210. Active loss heat generation control unit; 220. Real-time available heating capacity estimation unit; 230. Heating capacity decay trend calculation unit; 300. Heat transport and margin constraint module; 310. Heat source power comparison and arbitration unit; 320. Compressor speed constraint adjustment unit; 01. Compressor; 02. Front-end module; 03. Sensor; 04. Integrated evaporator core; 05. Electronic expansion valve; 06. Proportional valve; 07. Four-way reversing valve; 08. Plate heat exchanger; 09. Liquid-cooled four-way valve; 10. Expansion tank; 11. Water pump; 12. Motor and electronic control module; 13. Power battery; 14. SOV & TXV integrated valve. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0021] Before describing the specific embodiments of the present invention in detail, the basic structure and working principle of the heat pump system involved in this embodiment will be explained first.

[0022] The new energy vehicle thermal management system described in this embodiment comprises three hardware components: an air conditioning / heating and defogging system, a motor / electronic control and power battery thermal management cooling system, and a power battery heating system. The air conditioning / heating and defogging system includes a compressor, a front-end module, a four-way reversing valve, an electronic expansion valve, a proportional valve, an SOV & TXV integrated valve, an integrated evaporator core, and sensors, all connected sequentially via air conditioning piping to form a refrigerant circulation loop. The motor / electronic control and power battery thermal management cooling system and the power battery heating system are coupled to the aforementioned refrigerant circulation loop on the refrigerant side via a plate heat exchanger, while the coolant side includes a plate heat exchanger, a liquid-cooled four-way valve, a motor / electronic control module, a power battery, a water pump, and an expansion tank, all connected sequentially via water pipes to form a coolant circulation loop. Energy exchange occurs between the refrigerant and coolant in the plate heat exchanger, achieving deep coupling between the refrigerant and coolant circuits.

[0023] In cooling mode, the high-temperature and high-pressure gaseous refrigerant discharged by the compressor is condensed into liquid by the front-end module. After being throttled by the four-way reversing valve, electronic expansion valve and SOV&TXV integrated valve, it evaporates and absorbs heat in the integrated evaporator core, generating cold air that is sent into the passenger compartment.

[0024] In heating mode, the system switches the flow path via a four-way reversing valve. The high-temperature, high-pressure gaseous refrigerant discharged from the compressor directly enters the integrated evaporator core for condensation and heat release, transferring the heat to the passenger compartment. The condensed liquid refrigerant, after being throttled by a proportional valve, evaporates and absorbs heat in the front-end module or plate heat exchanger, extracting low-grade heat energy from the ambient air or motor coolant.

[0025] Based on the heating mode described above, this embodiment completely eliminates the independent PTC heater. When the ambient temperature is extremely low and the heat pump cannot meet the heating needs of the passenger compartment by absorbing heat from the ambient air alone, the system adjusts the four-way reversing valve and the proportional valve to allow the refrigerant to flow through the plate heat exchanger. This extracts the waste heat generated by the active heat generation of the motor from the coolant circuit of the motor control module, serving as a supplementary heat source. The active heat generation of the motor is achieved by injecting a pure direct-axis demagnetizing current into the motor stator windings—this current does not generate effective torque to drive the vehicle; its electrical energy is entirely converted into heat energy through the copper losses of the stator windings and the hysteresis and eddy current losses in the stator core. This makes the motor itself a controllable immersion heater, heating the coolant flowing through its coolant channels. This heat is transferred to the plate heat exchanger via the coolant circuit, extracted by the refrigerant circuit, transported by the compressor to the integrated evaporator core, and finally released into the passenger compartment.

[0026] The following is in conjunction with the appendix Figure 3-11 The specific implementation methods of this application will be further described in detail below: Reference Figure 3 The new energy vehicle thermal management system provided in this application includes three parts: an air conditioning cooling and heating system and a defogging system; a motor control and power battery thermal management cooling system; and a power battery heating system. The air conditioning cooling and heating system and the power battery heating system achieve the functions of cooling, heating and defogging of the passenger compartment through the heat exchange between the refrigerant and the air; the motor control and power battery thermal management cooling system and the power battery heating system achieve the energy exchange between the refrigerant and the coolant through the plate heat exchanger 08, and are coupled to the coolant circuit of the motor control module 12 and the power battery 13 through the liquid-cooled four-way valve 09, forming an integrated thermal management architecture with waste heat recovery function. The compressor 01, front-end module 02, four-way reversing valve 07, electronic expansion valve 05, proportional valve 06, SOV&TXV integrated valve 14, integrated evaporator core 04, and sensor 03 are connected sequentially through air conditioning pipes to form a refrigerant circulation loop. The plate heat exchanger 08, liquid-cooled four-way valve 09, motor control module 12, power battery 13, water pump 11, and expansion tank 10 are connected sequentially through water pipes to form a coolant circulation loop. The refrigerant and coolant exchange heat in the plate heat exchanger 08, achieving deep coupling between the two loops.

[0027] Reference Figure 4 In the integrated cooling mode of air conditioning, motor control, and battery, the refrigerant circuit flow path is as follows: The compressor 01 discharges high-temperature, high-pressure gaseous refrigerant, which is condensed into liquid by the front-end module 02. After being split by the four-way reversing valve 07, one path flows through the electronic expansion valve 05 and the SOV&TXV integrated valve 14 to the integrated evaporator core 04, while the other path flows through the electronic expansion valve 05 to the plate heat exchanger 08. After evaporating and absorbing heat, the two refrigerant paths converge and return to the compressor 01 via the sensor 03, forming a refrigerant circulation loop. The coolant circuit flow path is as follows: The coolant flows sequentially through the plate heat exchanger 08 → liquid-cooled four-way valve 09 → motor control module 12 and power battery 13 → water pump 11 → expansion tank 10 → liquid-cooled four-way valve 09, forming a closed loop. The refrigerant evaporates and absorbs heat in the plate heat exchanger 08, absorbing heat from the coolant circuit to achieve synchronous cooling of the motor control module 12 and the power battery 13. At the same time, the refrigerant evaporates and absorbs heat in the integrated evaporator core 04 to achieve cooling of the passenger compartment.

[0028] Reference Figure 5 In the integrated cooling mode for the motor, electronic control, and battery (this mode only cools the motor, electronic control, and battery, not the passenger compartment), the refrigerant circuit flow path is: compressor 01 → front-end module 02 → four-way reversing valve 07 → electronic expansion valve 05 → plate heat exchanger 08 → sensor 03 → compressor 01. The coolant circuit flow path is the same as... Figure 2Same. The refrigerant evaporates and absorbs heat in the plate heat exchanger 08, cooling only the motor control module 12 and the power battery 13 in the coolant circuit. The integrated evaporator core 04 does not participate in the operation.

[0029] Reference Figure 6 In air conditioning cooling mode (cooling only the passenger compartment), the refrigerant circuit flow path is: compressor 01 → front-end module 02 → four-way reversing valve 07 → electronic expansion valve 05 and SOV&TXV integrated valve 14 → integrated evaporator core 04 → sensor 03 → compressor 01. The refrigerant evaporates and absorbs heat in the integrated evaporator core 04 to cool the passenger compartment; the plate heat exchanger 08 does not participate in the operation.

[0030] Reference Figure 7 In the integrated rapid heating mode of air conditioning heating, motor control, and battery, the refrigerant circuit flow path is as follows: compressor 01 → front-end module 02 → four-way reversing valve 07 → proportional valve 06 and SOV&TXV integrated valve 14 → integrated evaporator core 04 and plate heat exchanger 08 → sensor 03 → compressor 01. Specifically, the high-temperature and high-pressure refrigerant after being reversed by the four-way reversing valve 07 enters the plate heat exchanger 08 through the proportional valve 06, and enters the integrated evaporator core 04 through the SOV&TXV integrated valve 14. The refrigerant condenses and releases heat in the integrated evaporator core 04 to heat the passenger compartment, and at the same time condenses and releases heat in the plate heat exchanger 08 to heat the coolant circuit. The coolant circuit flow path is as follows: coolant flows through plate heat exchanger 08 → liquid-cooled four-way valve 09 → power battery 13 → water pump 11 → expansion tank 10 → liquid-cooled four-way valve 09 → motor control module 12 → water pump 11 → liquid-cooled four-way valve 09, forming a closed loop. In this mode, the refrigerant simultaneously releases heat to the passenger compartment and the coolant circuit. The coolant carries the heat and flows sequentially through the power battery 13 and the motor control module 12, achieving rapid synchronous heating of the passenger compartment, power battery, and motor control module. The defogging function can be achieved through the combined control of the SOV&TXV integrated valve 14 and the integrated evaporator core 04.

[0031] Reference Figure 8In the conventional heating mode integrating air conditioning, heating, motor control, and battery, the refrigerant circuit flow path is: compressor 01 → front-end module 02 → four-way reversing valve 07 → proportional valve 06 and SOV&TXV integrated valve 14 → integrated evaporator core 04 → sensor 03 → compressor 01. The refrigerant only condenses and releases heat within the integrated evaporator core 04 to heat the passenger compartment; the plate heat exchanger 08 does not participate in the condensation and heat release on the refrigerant side. The coolant circuit flow path is: coolant flows through plate heat exchanger 08 → liquid-cooled four-way valve 09 → power battery 13 → water pump 11 → expansion tank 10 → liquid-cooled four-way valve 09 → motor control module 12 → water pump 11 → liquid-cooled four-way valve 09, forming a closed loop. In this mode, the refrigerant only heats the passenger compartment, while the coolant circuit absorbs heat from the refrigerant side through the plate heat exchanger 08 (which acts as a condenser) to heat the power battery 13 and the motor control module 12, achieving normal temperature rise. The demisting function is also achieved through the combination of the SOV&TXV integrated valve 14 and the integrated evaporator core 04.

[0032] Reference Figure 9 In the rapid heating mode of the power battery, the refrigerant circuit flow path is: compressor 01 → front-end module 02 → four-way reversing valve 07 → proportional valve 06 → plate heat exchanger 08 → sensor 03 → compressor 01. The refrigerant condenses and releases heat in the plate heat exchanger 08, transferring the heat to the coolant circuit. The coolant circuit flow path is: coolant flows through plate heat exchanger 08 → liquid-cooled four-way valve 09 → power battery 13 → water pump 11 → expansion tank 10 → liquid-cooled four-way valve 09 → motor control module 12 → water pump 11 → liquid-cooled four-way valve 09, forming a closed loop. In this mode, all the heat from the refrigerant is used to heat the coolant. The coolant flows successively through the power battery 13 and the motor control module 12, achieving rapid heating of the power battery, while the motor control module 12 is also preheated.

[0033] Reference Figure 10 In the normal heating mode of the power battery, the refrigerant circuit does not operate; the power battery 13 is heated only by the waste heat generated by the operation of the motor control module 12. The flow path of the coolant circuit is as follows: coolant flows through plate heat exchanger 08 → liquid-cooled four-way valve 09 → power battery 13 → water pump 11 → expansion tank 10 → liquid-cooled four-way valve 09 → motor control module 12 → water pump 11 → liquid-cooled four-way valve 09, forming a closed loop. When the coolant flows through the motor control module 12, it absorbs the waste heat generated by its operation. When it carries heat through the power battery 13, it releases the heat, achieving normal heating of the power battery. At this time, the plate heat exchanger 08 only serves as part of the coolant channel and does not perform heat exchange on the refrigerant side.

[0034] Reference Figure 11In air conditioning heating (including defogging) mode, the refrigerant circuit flow path is: compressor 01 → front-end module 02 → four-way reversing valve 07 → proportional valve 06 and SOV&TXV integrated valve 14 → integrated evaporator core 04 → sensor 03 → compressor 01. The refrigerant condenses and releases heat within the integrated evaporator core 04 to heat the passenger compartment. The defogging function is achieved through the cooperation of the SOV&TXV integrated valve 14 and the integrated evaporator core 04. Specifically, by controlling the opening of the SOV&TXV integrated valve 14, the distribution of refrigerant within the integrated evaporator core 04 is adjusted, causing localized dry warm air to be generated within the integrated evaporator core 04 to remove fog from the windshield. This mode does not involve heat exchange in the coolant circuit.

[0035] However, in the tightly coupled architecture of heat generation and heat pump transport described above, a fundamental control problem arises: all the heat generated by the motor must be transported to the passenger compartment in real time via the heat pump. The heat is transferred from the motor side through the coolant circuit, plate heat exchanger, and refrigerant circuit to the integrated evaporator core, without any intermediate heat storage buffer. These characteristics determine that the system is extremely sensitive to the instantaneous power balance between heat generation and transport.

[0036] This problem is particularly acute in extremely cold start-up scenarios. At this point, both the passenger compartment and the motor control module are at extremely low temperatures, causing the heat pump's heating efficiency ratio to plummet due to the excessively low evaporation temperature, or even preventing it from starting normally. Traditional solutions rely on a PTC (Power Transmitter) for rapid, high-power heating. However, without the PTC, the only auxiliary heat source—the motor control module—has an initial temperature the same as the ambient temperature, making it unable to provide effective heat instantly. The primary technical challenge after eliminating the PTC is how to rapidly activate the motor and generate heat while simultaneously providing initial heating to the passenger compartment, even when the motor itself is cold.

[0037] In extremely cold, continuous heating scenarios, the motor needs to maintain a high-power heating state for an extended period to meet the heating needs of the passenger compartment. As the heating process continues, heat accumulates in the permanent magnet, and the temperature continues to rise, causing the motor's maximum allowable heat generation power to gradually decrease along the demagnetization protection boundary. Moreover, this decrease is a slow and continuous gradual process. Traditional direct feedback control based on passenger compartment temperature deviation can only reflect the degree to which the heat demand on the passenger compartment side is met, and system thermal inertia identification can only reflect the dynamic response hysteresis characteristics of the loop. Neither of these includes information about the decrease in the motor's own heat source capacity. If the control strategy does not consider the above-mentioned decrease trend, it will continue to issue excessively high heat generation commands to the motor until the permanent magnet temperature touches the demagnetization protection threshold, triggering hardware-forced power limiting. The instantaneous drop in heat source power will directly cause the interruption of passenger compartment heating and drastic temperature fluctuations.

[0038] Furthermore, in transient operating condition switching scenarios, such as in congested urban traffic where the average power of the motor is low and there is insufficient waste heat, while the motor generates a large amount of waste heat instantaneously during short-term rapid acceleration or hill climbing, the system lacks a PTC as a power buffer. If the heat pump's transport capacity becomes bottlenecked due to factors such as compressor speed limitations, low ambient temperature leading to a decrease in energy efficiency ratio, or reduced heat exchange efficiency of front-end modules, and the motor continues to generate heat at full capacity according to the original heat generation command, the generated heat will not be extracted in time, forming heat accumulation in the motor coolant circuit, which in turn causes an abnormal rise in coolant temperature. This forces the system to reduce the available heating capacity as the permanent magnet temperature approaches the demagnetization boundary, ultimately triggering demagnetization protection degradation. This causes the entire thermal management control loop to fall into a vicious cycle of excessive heat generation—heat accumulation and temperature rise—heat capacity limitation—margin narrowing—further relative excess heat generation, which in severe cases can cause interruption of heating in the passenger compartment.

[0039] refer to Figure 1 As shown, to solve the above-mentioned technical problems, this embodiment proposes a thermal management system for new energy vehicles. Its core lies in constructing an electric-thermal dual-loop cross-coupling linkage control architecture with the real-time heat generation capacity of the motor as the absolute benchmark and bidirectional information penetration and logical intermodulation between each control unit. This system completely eliminates the independent PTC heater. Through the coordinated work of the following three control modules and their internal units, it achieves precise closed-loop management of heat generation and transport in various scenarios such as extreme cold start-up, steady-state heating, and transient operating condition switching. Specifically, a thermal management system for new energy vehicles includes: The heat generation command generation module 100 analyzes the thermal time constant and calculates the target temperature rise rate; The motor heat and capacity feedback module 200 calculates the direct-axis current command amplitude and obtains the heat pump transport capacity margin. It uses the heat pump transport capacity margin as a dynamic adjustment factor for generating the direct-axis current command amplitude and executes an adaptive constraint strategy for motor heat generation power to finally obtain the direct-axis current command amplitude. Input the direct-axis current command amplitude to the motor loss model, and the motor loss model outputs the real-time heat generation power; calculate the maximum allowable heat generation power that the permanent magnet can withstand under the current state without causing irreversible demagnetization; The demagnetization safety power margin is calculated by real-time heat generation power and maximum allowable heat generation power. Then, the heat generation attenuation gradient used to adjust the target temperature rise rate to the corrected temperature rise rate is obtained by analysis. The motor heat and capacity feedback module 200 is executed again until the thermal stability control state is reached. The heat transport and margin constraint module 300 obtains the heat source power target, calculates the target speed required by the compressor based on the heat source power target, and calculates the heat pump transport capacity margin.

[0040] The working principles of the aforementioned heat generation command generation module 100, motor heat and capacity feedback module 200, and heat transport and margin constraint module 300 are as follows: The heat generation command generation module 100 includes an online thermal inertia identification unit 110 and a target temperature rise rate decision unit 120. Its specific working principle is as follows: When the compressor speed undergoes a step change, the condensing pressure does not respond immediately, but rather exhibits a gradual change process with first-order inertial hysteresis. The fundamental physical cause of this first-order inertial hysteresis is that the refrigerant needs to undergo a heat and mass transfer transition stage to establish a stable phase change and flow state in the pipes, heat exchangers, and valve bodies. The time scale of this transition stage directly reflects the overall thermal inertia of the entire heat pump circuit and heat exchange links.

[0041] Based on the above physical phenomena, the thermal inertial online identification unit 110 receives the compressor speed sensor signal and the condensing pressure sensor signal from the front-end module side, and performs real-time comparative analysis on the two sets of signals to identify the time delay of the condensing pressure response curve relative to the step change of the compressor speed; thereby continuously monitoring the lag relationship between the condensing pressure build-up rate and the compressor speed change; and estimating a thermal time constant that reflects the overall thermal response lag. The thermal time constant is not a fixed value, but rather changes dynamically with factors such as temperature and refrigerant migration. It describes the delay between the generation of heat by the motor and the temperature rise at the passenger compartment air outlet. This makes traditional direct feedback control based on temperature deviation prone to temperature overshoot and oscillation under extremely cold conditions. The specific thermal time constant is as follows: ; in: The preset proportional threshold characterizes the degree of response completion achieved during the transition of the condensing pressure from its initial steady-state value to a new steady-state value; it is determined based on the physical characteristics of a first-order inertial step response. For a typical first-order inertial step response, after a step change in the input, the output amplitude will reach the total change after a time constant. Times. Based on the above physical laws, a preset proportional threshold is established. It was calibrated to 0.632. In practical engineering applications, the proportional threshold... It can also be adjusted within the range of 0.6 to 0.65 according to the corresponding identification accuracy requirements of the heat pump air conditioning system and the calibration test results on specific vehicle models, in order to adapt to the actual dynamic response characteristics of different heat pump systems; The starting moment of a step change in compressor speed is determined by real-time monitoring of the compressor target speed command signal issued by the heat pump controller. Specifically, when the amplitude change of the compressor target speed command exceeds a calibrated step judgment threshold within a preset sampling period, and the changed target speed command remains stable in multiple consecutive sampling points in the subsequent sampling period, a valid step change in compressor speed is determined, and the sampling moment when the amplitude change first exceeds the threshold is recorded as the starting moment. The initial steady-state value of the condensing pressure before a speed jump is determined. This value is obtained by continuously collecting signals from the condensing pressure sensor and performing a steady-state determination before the compressor speed changes abruptly. The steady-state determination condition is that within a preset time window before the speed jump, the fluctuation amplitude of the condensing pressure signal is continuously lower than a calibrated steady-state fluctuation threshold. When this condition is met, the average value of the condensing pressure samples within that time window is taken as the initial steady-state value. The new steady-state value of the condensing pressure after a speed jump is determined based on the correspondence between the compressor speed and the current operating conditions of the refrigerant circulation loop in the heat pump air conditioning system; it is determined by querying a pre-calibrated mapping relationship. This mapping relationship reflects the steady-state value of the condensing pressure at thermodynamic equilibrium under different ambient temperatures, compressor speeds, and system refrigerant charge conditions. Specifically, this mapping relationship uses the target compressor speed after the speed jump and the current ambient temperature collected by the temperature sensor as inputs, and obtains the corresponding new steady-state pressure value by looking up a two-dimensional mapping table pre-stored in the controller. The moment when the actual value of the condensing pressure reaches the pressure value defined by the expression in parentheses.

[0042] The target temperature rise rate decision unit 120 receives the deviation signal between the actual temperature and the target temperature from the temperature sensors located in the crew compartment. To avoid the adverse effects of the response lag represented by the thermal time constant in the thermal inertia online identification unit 110 on the control quality, the thermal time constant output by the thermal inertia online identification unit 110 is used as a key factor for calculation. Based on the functional relationship that automatically decays as the thermal time constant increases, a target temperature rise rate corresponding to a dynamic motor body is calculated, as follows: ; in: : The target temperature rise rate of the motor body, that is, the set value of the expected temperature rise of the motor per unit time; The proportional gain coefficient is determined by performing a step response test on the thermal management control loop during the system calibration phase. Specifically, given the known thermal time constant... Under the calibration conditions, a set of preset temperature deviation step signals are input to the thermal management controller, and the overshoot and settling time of the actual temperature response curve of the crew cabin are observed and recorded. With the optimization objective of minimizing the overshoot and settling time of the response curve, the proportional gain coefficient is iteratively tuned, and the parameter value that satisfies the above optimization objective is taken as the calibrated value. It is then stored in the heat pump controller for online recall; The target temperature of the passenger compartment is the heating target temperature value that is manually set by the passengers through the onboard human-machine interface. The actual temperature of the passenger compartment is collected and fed back in real time by a temperature sensor located in the passenger compartment near the air outlet path of the integrated evaporator core. The temperature sensor converts the sensed passenger compartment air temperature into an electrical signal, which is processed by the signal conditioning circuit and then sent to the target temperature rise rate decision unit 120 through the vehicle communication network. The preset minimum time constant limit is used to prevent calculation overflow caused by an excessively small denominator when the system's thermal inertia is extremely small or zero. It is a constant value pre-calibrated according to the safety requirements of the heat pump system. Its physical meaning lies in the thermal time constant identified when the heat pump air conditioning system is under certain special operating conditions, such as before or immediately after the heat pump compressor starts. When the denominator is extremely small or even close to zero, It will remain a non-zero positive value to prevent the target temperature rise rate from overflowing or generating an excessively large command value that is physically unrealizable. The specific value is determined during the system calibration phase based on the constraints of the maximum allowable rate of change of compressor speed and the temperature control accuracy of the passenger compartment, through simulation and actual vehicle calibration. It is usually selected as one-hundredth to one-tenth of the typical thermal time constant of the system.

[0043] Based on the above target temperature rise rate From the expression, it can be seen that when the identified thermal time constant... The larger the denominator, the larger the denominator. The larger the value, the higher the target temperature rise rate under the same temperature deviation. The temperature automatically tends to be moderate; conversely, when thermal inertia is low, the target temperature rise rate increases accordingly. This mechanism ensures that the required motor heating rate matches the actual response speed of the heat pump system, thus preventing overshooting and oscillation of the cabin temperature caused by control commands exceeding the response capability of the heat pump system.

[0044] Furthermore, to avoid the target temperature rise rate output by the target temperature rise rate decision unit 120 being merely a one-way command for the motor's heat generation rate, while the heat pump controller lacks real-time awareness of the actual heat capacity the motor can provide, thus causing the heat pump side to issue heat transfer demands exceeding the motor's actual capacity due to information asymmetry when formulating heat transfer strategies, leading to abnormal drops in coolant temperature or system instability risks such as frost formation on the heat pump evaporator, the motor heat and capacity feedback module 200 receives the target temperature rise rate output by the target temperature rise rate decision unit 120, adjusts the motor's active heat generation power by controlling the direct-axis current injected into the motor windings, and calculates the current maximum available heating capacity based on the motor's real-time status, feeding back the current maximum available heating capacity to the heat pump controller. This provides the subsequent heat transfer and margin constraint module 300 with a real-time safe upper limit for the motor's heat generation capacity, ensuring that the heat pump controller's heat transfer demand is always constrained within the range of heat that the motor can safely provide instantaneously. Thus, in a system architecture that completely eliminates the independent positive temperature coefficient thermistor heater, closed-loop collaborative control where heat generation capacity determines heat transfer behavior is achieved. The specific motor heat and capacity feedback module 200 includes an active loss heat generation control unit 210, a real-time available heat capacity estimation unit 220, and a heat capacity attenuation trend calculation unit 230, wherein: The active loss heat generation control unit 210 receives the target temperature rise rate from the target temperature rise rate decision unit 120, and obtains the direct-axis current command amplitude corresponding to the pure direct-axis demagnetizing current injected into the stator winding of the motor based on the target temperature rise rate. That is, the control target with the target temperature rise rate as the dimension is converted into a precise executable direct-axis current command amplitude, so that the motor body becomes a controllable immersion heater. This direct-axis current does not generate effective torque to drive the vehicle, and its electrical energy is completely converted into heat energy in the form of copper loss and iron loss, thereby raising the temperature of the motor and coolant at a controllable rate.

[0045] Finally, the calculated direct-axis current command amplitude is output to the current loop regulator of the motor controller. Through pulse width modulation, the inverter power device is driven to inject a direct-axis demagnetizing current of the corresponding amplitude into the motor stator winding, so that the motor body temperature is raised controllably at the rate specified by the target temperature rise rate. The coolant flowing through the motor coolant channel is heated simultaneously. This heat is transferred to the plate heat exchanger through the coolant circuit, and then extracted and transported to the crew compartment by the refrigerant circuit.

[0046] The active loss heat generation control unit 210 works on the following principle: When a pure direct-axis current is injected into the stator winding of the motor, this current generates ohmic losses in the stator winding resistance, and simultaneously excites an alternating magnetic field in the stator core, generating hysteresis losses and eddy current losses. All the electrical energy from these two types of losses is converted into heat energy, and no effective electromagnetic torque is generated to drive the rotor. Therefore, by precisely controlling the amplitude of the injected direct-axis current command, the total heat generation power of the motor can be precisely controlled, thereby controlling the target temperature rise rate of the motor body and the coolant flowing through its coolant channels.

[0047] Based on the aforementioned physical mechanism, the target temperature rise rate is converted into a target value for the total heat generation power required to control the motor. The required direct-axis current command amplitude to achieve this heat generation power is then calculated. Since the motor's heat generation power is approximately proportional to the square of the injected direct-axis current command amplitude, the direct-axis current command amplitude is as follows: ; in: This represents the target total heat dissipation power that the motor needs to achieve. The equivalent thermal capacity of the motor is the amount of heat that the motor body and its internal coolant need to absorb to increase the temperature by one unit. It is a parameter that has been pre-calibrated through offline testing. The target temperature rise rate; The equivalent heating resistance of the motor characterizes the heat generated within the motor per unit direct-axis current command amplitude. This parameter incorporates the equivalent thermal effects of stator winding resistance and core losses, and is a parameter pre-calibrated through offline testing and corrected online according to winding temperature. The aforementioned equivalent heating resistance... The online correction process is as follows: Since the actual resistance value of the stator winding changes with the winding temperature, the active loss heat generation control unit 210 continuously receives the current winding temperature from the temperature sensor built into the motor controller, and adjusts the control according to the pre-calibrated copper winding resistance-temperature curve. The reference value is corrected in real time to ensure the accuracy of the direct-axis current command amplitude calculation.

[0048] During the calculation of the direct-axis current command amplitude, the active heat loss generation control unit 210 simultaneously receives the heat pump transport capacity margin output in real time by the heat transport and margin constraint module 300, and uses it as a constraint correction factor for the generation of the direct-axis current command amplitude. The specific reason is as follows: The current system architecture completely eliminates the independent PTC and relies solely on the active heat loss of the motor as the only heating source. Under this architecture, the entire source of heating for the passenger compartment depends on the heat generated by the motor. The heat is transferred from the motor side through the coolant circuit, plate heat exchanger, and refrigerant circuit to the integrated evaporator core and finally released into the passenger compartment, without any intermediate heat storage buffer. These characteristics determine that the system is extremely sensitive to the instantaneous power balance between heat generation and heat transfer. The target temperature rise rate only considers the heat demand side of the passenger compartment and the motor demagnetization protection side, specifying the heat generation rate that the motor should achieve. However, it does not consider whether the heat pump side has the actual ability to remove some of the heat in a timely manner under the current operating conditions. If the heat pump's heat removal capacity is bottlenecked due to factors such as compressor speed limitations, low ambient temperature leading to a decrease in energy efficiency ratio, or reduced heat exchange efficiency of the front-end module, and the motor still generates heat at full capacity according to the target temperature rise rate, the generated heat will not be extracted in time, forming a heat accumulation in the motor coolant circuit. This will cause the coolant temperature to rise abnormally, forcing the subsequent real-time available heating capacity estimation unit 220 to lower the current maximum available heating capacity as the permanent magnet temperature approaches the demagnetization boundary. Ultimately, this triggers the demagnetization protection degradation, causing the entire thermal management control loop to fall into a vicious cycle of increasing heat accumulation and production limitations, which in severe cases can lead to a interruption of heating in the passenger compartment.

[0049] The heat pump transport capacity margin is determined by the heat transport and margin constraint module 300 during compressor speed regulation, indicating how much surplus heat the heat pump has under current operating conditions. When this margin is sufficient, it means the heat pump has the capacity to absorb more heat, and the motor's heat generation potential can be fully realized. Conversely, when this margin continuously narrows, it indicates that the heat pump's transport capacity is approaching the upper limit of the motor's current heat output; continuing to maintain or increase heat generation will exceed the system's safety boundary.

[0050] Based on the above logic, the active loss heat generation control unit 210 uses the heat pump transport capacity margin as a constraint correction factor for the direct-axis current command amplitude, and executes the following adaptive constraint strategy for motor heat generation power: When the heat pump's heat transfer capacity margin falls below a preset tightening threshold, it indicates that the actual heat transfer capacity of the heat pump is approaching the upper limit of the heat that the motor can currently provide. If the current heat generation rate continues to be maintained, the generated heat will not be transferred in time and will accumulate on the motor side, leading to an abnormal rise in coolant temperature or triggering demagnetization protection degradation. At this time, the active loss heat generation control unit 210 actively applies an attenuation factor proportional to the degree of margin narrowing above the direct-axis current command amplitude corresponding to the target temperature rise rate. This smoothly reduces the injected direct-axis current command amplitude, constraining the actual heat generation rate of the motor within the range that the heat pump's heat transfer capacity can absorb, thereby preventing the generation of redundant heat that cannot be effectively transferred and avoiding energy waste and system heat accumulation. The final direct-axis current command amplitude used to drive the inverter to inject direct-axis demagnetizing current into the motor stator winding is as follows: ; In the formula: The direct-axis current command amplitude is calculated from the target temperature rise rate through the aforementioned conversion. The attenuation factor has a value range of 1. ; The preset tightening threshold; Attenuation factor Specifically, it refers to the proportion of the current remaining transport capacity on the heat pump side to the minimum safe transport margin required by the system, i.e., when the heat pump transport capacity margin... Greater than or equal to the preset tightening threshold When the carrying capacity is sufficient, there is no need to reduce heat generation, and the decay factor remains at 1; when the margin is sufficient... Decreasing to the tightening threshold The following indicates that the handling capacity has entered a strained range, and the attenuation factor decreases proportionally with the margin, thus constraining the motor's heat generation rate to a level matching the handling capacity. The corresponding expression is as follows: ; in: : Attenuation factor, applied to the base direct-axis current command amplitude to generate the final output direct-axis current command amplitude; Heat pump transport capacity margin; The maximum available heating capacity is obtained by the real-time available heating capacity estimation unit 220 within the same control cycle by taking the smaller of the estimated value of the motor loss model and the maximum allowable heat generation power determined by the demagnetization protection boundary. It represents the upper limit of the heating power that the motor can safely output under the current permanent magnet temperature and demagnetization protection constraints. The actual power transferred by the compressor at present is estimated by the compressor speed constraint adjustment unit 320 based on the real-time operating parameters of the compressor, representing the actual heat power extracted from the refrigerant side of the plate heat exchanger and delivered to the integrated evaporator core at the current moment on the heat pump side. The preset minimum attenuation factor limit is a positive constant less than 1 determined by system calibration. It is used to prevent the attenuation factor from being too small, which would cause the direct axis current command amplitude to be too low and completely lose the heat generation capacity.

[0051] Tightening threshold Provides a trigger boundary for the attenuation factor in the active loss heat generation control unit 210: when the heat pump transport capacity margin... Above this tightening threshold When the heat pump's actual transport capacity is within a certain range, it indicates that there is still a sufficient safety margin between the actual transport capacity on the heat pump side and the upper limit of the motor's usable heating capacity, therefore the motor can generate heat at full capacity as needed; when the heat pump's transport capacity margin is sufficient... Below this tightening threshold When the current heat generation rate is maintained, it indicates that the heat pump's heat transfer capacity is approaching the upper limit of the motor's current heat supply, and the power balance between the two is at a critical state. If the current heat generation rate continues, the generated heat will exceed the heat pump's absorption capacity, leading to heat accumulation in the motor's coolant circuit. This could cause an abnormal rise in coolant temperature or trigger demagnetization protection degradation. Therefore, it is necessary to apply attenuation to the direct-axis current command to constrain the heat generation rate. Specific tightening threshold... It depends on how much transport margin can be safely accommodated at the current moment, and the instantaneous fluctuations.

[0052] In the current scenario, all heat generated by the motor must be transported in real time via a heat pump, and heat generation and transport are extremely sensitive to heat accumulation. The degree of risk of heat accumulation is determined by three core factors: First, the total available heating capacity of the motor; the larger the capacity, the greater the tolerable absolute margin fluctuation. Second, the rate at which the available heating capacity of the motor approaches the demagnetization protection boundary; the faster the approach, the more sufficient the safety margin should be. Third, the urgency of the passenger compartment's need for heat generation; the more urgent the need, the more appropriately the safety constraints should be relaxed to ensure the rate of warming.

[0053] Based on the logic of the above instantaneous fluctuations, the tightening threshold is... The determination method is as follows: based on the current maximum available heating capacity output by the real-time available heating capacity estimation unit 220. Based on the heating capacity attenuation trend calculation unit 230, the heating capacity attenuation gradient is superimposed. The tightening threshold is obtained by subtracting the margin released due to rising temperature demand from the directly provided dynamic bias. Specifically, it is as follows: ; in: The current maximum available heating capacity is obtained by taking the smaller of the estimated value from the motor loss model and the demagnetization protection boundary value from the real-time available heating capacity estimation unit 220. The heating capacity attenuation gradient is obtained by the real-time available heating capacity estimation unit 220 through continuous monitoring of the narrowing rate of the difference between the estimated value of the motor loss model and the demagnetization protection boundary value. The target temperature rise rate in the target temperature rise rate decision unit 120; The maximum allowable temperature rise rate of the motor is determined by the physical characteristics of the motor and is a preset fixed parameter.

[0054] The real-time available heating capacity estimation unit 220 acquires the motor loss model and uses it to estimate the current real-time heat generation power. ; in: The real-time heat generation power estimated by the motor loss model represents the theoretical heat generation power that the motor can output under the current direct-axis current injection without considering demagnetization constraints. The direct-axis current command amplitude is provided by the active loss heat generation control unit 210; Equivalent heating resistance is the contribution of the equivalent thermal effect of stator winding copper loss and core loss. This parameter is based on the offline calibrated reference value and is obtained after online correction according to the winding temperature fed back in real time by the temperature sensor built into the motor controller and the pre-calibrated copper winding resistance-temperature curve.

[0055] In parallel, the temperature of the permanent magnet is continuously monitored, and based on a strict demagnetization protection boundary function, the maximum allowable heat generation power that the permanent magnet can withstand under the current state without causing irreversible demagnetization is calculated. The specific demagnetization protection boundary function takes the permanent magnet temperature as input and outputs the maximum allowable heat generation power that will not cause irreversible demagnetization of the permanent magnet at that temperature. The current temperature of the permanent magnet is collected in real time by a temperature sensor located inside the motor, or estimated online by the motor thermal model based on parameters such as winding temperature, coolant temperature, and motor losses.

[0056] The minimum value between the real-time heat production power and the maximum allowable heat production power is defined as the current maximum available heat capacity and is transmitted to the heat pump controller in real time through the vehicle network as the core feedback signal.

[0057] And using the target temperature rise rate After calculating the direct-axis current command amplitude, the heating capacity attenuation trend calculation unit 230 adjusts the target temperature rise rate to a corrected temperature rise rate based on the real-time heat generation power and maximum allowable heat generation power output by the motor loss model. At this time, the active loss heat generation control unit 210 and the real-time available heating capacity estimation unit 220 are executed again until a thermally stable control state is reached; that is, when the heat generation capacity attenuation trend represented by the heating capacity attenuation gradient tends to converge, the change in the corrected temperature rise rate between adjacent control cycles is lower than the preset convergence threshold, and the heat pump transport capacity margin stabilizes at the tightening threshold, a thermally stable control state is reached; the specific corrected temperature rise rate is as follows: Due to the target temperature rise rate in the target temperature rise rate decision unit 120 Calculations based solely on the temperature deviation and thermal time constant of the passenger compartment essentially only provide static correction for the system's thermal inertia lag, assuming the motor's heating output capacity remains constant and failing to include information on the impact of changes in the motor's own thermal state on its heat generation capacity. However, in current extreme cold continuous heating scenarios where independent positive temperature coefficient thermistor heaters are completely eliminated and the motor's active heat loss is the sole heating source, the motor needs to maintain a high-power heating state for extended periods to meet the passenger compartment's heating needs. As heat accumulates continuously in the permanent magnets and the temperature rises, the motor's maximum permissible heat generation power gradually decreases along the demagnetization protection boundary. Furthermore, the aforementioned decay process is a slow and continuous gradual process that cannot be accurately identified using parameters such as cabin temperature deviation or thermal time constant. The former only reflects the degree to which the cabin's heat demand is met, and the latter only reflects the dynamic response lag characteristics of the heat pump system; neither of these includes information about the decay of the motor's own heat source capacity. If the uncorrected target temperature rise rate is continuously used, excessively high heat generation commands will be continuously issued to the motor until the permanent magnet temperature accumulates and touches the demagnetization protection threshold, triggering hardware-mandated power limiting. At this point, the instantaneous drop in heat source power will directly cause cabin heating interruption and drastic temperature fluctuations.

[0058] To prevent the maximum allowable heat generation power from continuously decreasing along the demagnetization protection boundary due to the gradual accumulation of permanent magnet temperature during continuous high-power heating of the motor, the target temperature rise rate is calculated only based on the passenger compartment temperature deviation and thermal time constant, and the motor's heating output capacity is assumed to remain constant. This results in the continuous issuance of excessively high heat generation commands to the motor until the permanent magnet temperature touches the demagnetization protection threshold, triggering hardware-forced power limiting, ultimately causing a sudden drop in heat source power, interruption of passenger compartment heating, and severe temperature fluctuations. The heating capacity attenuation trend calculation unit 230 further calculates a heating capacity attenuation gradient that reflects the decreasing trend of heat generation capacity based on the maximum available heating capacity in the real-time available heating capacity estimation unit 220. Based on the target temperature rise rate in the target temperature rise rate decision unit 120, the target temperature rise rate is adjusted to a corrected temperature rise rate based on the heating capacity attenuation gradient. The heating capacity attenuation gradient is obtained by continuously monitoring the rate at which the motor loss model estimate gradually approaches the demagnetization protection boundary value. Its more detailed working principle is as follows: First, at the current sampling time of the corresponding thermal state parameters of the heat pump system. Compared with the previous sampling time The difference between the real-time heat generation power output from the motor loss model in the real-time available heating capacity estimation unit 220 and the maximum allowable heat generation power is calculated. This difference represents the remaining demagnetization safety power margin of the motor at the current moment. ; ; in and These are the demagnetization safety power margins for the current time and the previous time, respectively. , These are the estimated values ​​of the motor loss model and the boundary values ​​of the demagnetization protection, respectively. Furthermore, during the calculation process of the real-time available heating capacity estimation unit 220, the motor loss model is used as the estimation tool for real-time heat generation power, and the demagnetization protection boundary function is used as the basis for determining the maximum allowable heat generation power: the motor loss model calculates the actual heat generation power generated by the motor under the current operating condition based on the amplitude of the currently injected direct-axis current command and the equivalent heating resistance after online correction, and this value is the real-time heat generation power; the demagnetization protection boundary function outputs the upper limit of safe heat generation power that will not cause irreversible demagnetization at the current temperature of the permanent magnet, and this value is the maximum allowable heat generation power. Therefore, the estimated value of the motor loss model and the demagnetization protection boundary value correspond to the real-time heat generation power and the maximum allowable heat generation power in the real-time available heating capacity estimation unit 220. Subsequently, the periodic change in the demagnetization safety power margin is divided by the sampling time interval of the corresponding thermal state parameters of the heat pump system to obtain the heating capacity attenuation gradient. : ; in: Demagnetization safety power margin at the previous sampling time; Demagnetization safety power margin at the current sampling time; : Sampling time interval, i.e., the time step between two consecutive calculations.

[0059] When the permanent magnet temperature is low and the risk of demagnetization has not yet appeared, the estimated value of the motor loss model is... Demagnetization protection boundary value There is a large margin between them. and All are relatively large and their values ​​are similar. The value is close to zero or negative. As the temperature of the permanent magnet gradually rises due to continuous heating, As the demagnetization protection boundary function gradually decreases, the demagnetization safety power margin increases. Gradually narrowing, It turns positive and gradually increases, quantitatively reflecting the urgency of the decline in the motor's heat generation capacity.

[0060] The specific working principle of the temperature rise rate correction in the heating capacity attenuation trend calculation unit 230 is as follows: The specific heating capacity attenuation gradient is obtained by continuously monitoring the rate at which the current maximum available heating capacity gradually approaches the demagnetization protection boundary value from the motor loss model estimate. This reflects the urgency and attenuation trend of the motor being forced to reduce its heat generation power due to the continuous rise in permanent magnet temperature. However, the target temperature rise rate in the target temperature rise rate decision unit 120 is only calculated based on the cabin temperature deviation and thermal time constant. It can only perform static correction for the system's thermal inertia lag problem, assuming that the motor's heating output capacity remains constant. However, in this example, under the extremely cold continuous heating scenario where the independent PTC is completely eliminated and only the motor's active loss heat generation is used as the sole heating source, the motor will maintain a high power consumption heating state for a long time, the permanent magnet heat will continue to accumulate, and the heating upper limit will gradually decrease. This slow attenuation process cannot be identified by the temperature deviation and thermal time constant. If the uncorrected target temperature rise rate is used continuously, it will continuously issue higher heat generation commands to the motor until the permanent magnet touches the demagnetization threshold and the power is forcibly limited by hardware. The instantaneous drop in heat source power will directly cause the interruption of cabin heating and drastic temperature fluctuations. Therefore, the heating capacity attenuation trend calculation unit 230 superimposes a compensation amount that is inversely related to the attenuation gradient on the target temperature rise rate, and finally obtains the corrected temperature rise rate. Based on the corrected temperature rise rate, the heat pump side can detect the attenuation trend of the heat source capacity in advance and actively reduce the heat production command before the motor actually reaches the demagnetization protection boundary and before the heat generation power is forcibly limited. This avoids a step disturbance to the passenger cabin temperature control caused by the sudden degradation of the heat source, and realizes the transformation from passively responding to demagnetization protection to actively adapting to the heat source trend. The specific corrected temperature rise rate is as follows: ; in: : Heating capacity attenuation gradient; The attenuation compensation gain coefficient is determined through a standardized calibration process performed on a dedicated test bench or actual vehicle during the system calibration phase. The core objective of this calibration process is to find an optimal set of gain coefficients, minimizing the temperature fluctuation amplitude in the passenger compartment throughout the entire process of the motor transitioning from normal heating to the demagnetization protection boundary. This ensures that the response of the corrected temperature rise rate to the heating capacity attenuation gradient is neither sluggish nor excessive. The specific working principle of the calibration process is as follows: First, establish a controllable calibration condition. In a test environment where the ambient temperature is stably controlled at a preset extreme cold calibration point (e.g., -20℃), set the target temperature of the passenger compartment to the calibration target value (e.g., 22℃), start the heat pump system, and bring the heat pump and motor into a stable heating operation state. At this time, the temperature of the motor permanent magnet is low, the demagnetization margin is sufficient, and the heat pump system operates normally at the target temperature rise rate.

[0061] Subsequently, by external loading or calibration software intervention, the heat dissipation capacity of the motor coolant circuit is gradually reduced or the direct-axis current of the motor is gradually increased, so that the permanent magnet temperature rises slowly at an approximately constant rate, simulating the real process of the permanent magnet gradually accumulating heat and gradually decreasing heating capacity under extremely cold continuous heating scenarios.

[0062] In the above process, the traversal is performed with a preset step size (e.g., 0.1). Within a set of candidate values ​​within the calibration range, a complete decay process test is performed on each candidate value. Specifically, for each candidate... The target temperature rise rate decision unit 120 operates at this gain and receives the heating capacity decay gradient output by the heating capacity decay trend calculation unit 230. According to the modified expression The temperature rise rate is dynamically adjusted and corrected until the permanent magnet temperature reaches the demagnetization protection boundary and the heat generation power is forcibly limited by hardware.

[0063] For each complete decay process test, the actual temperature of the passenger compartment was recorded over time throughout the process, and two key evaluation indicators were extracted: first, the maximum deviation of the passenger compartment temperature from the target temperature, used to measure the severity of the heating interruption; and second, the adjustment time required from the forced power limitation of the motor to the recovery of the passenger compartment temperature to the target temperature range, used to measure the recovery capability of the heat pump system. A weighted combination of these two indicators was used as the candidate. The corresponding control quality evaluation function.

[0064] when When the value is too small, the correction term is applied. The response to the heat generation decay gradient is too sluggish. The corrected temperature rise rate remains at a high level when the motor is close to the demagnetization boundary, which causes the motor heat generation command to fail to be reduced in time. Ultimately, it will still trigger the hardware to force power limiting, resulting in a large step drop in the temperature of the crew cabin.

[0065] when When the value is too large, the correction term is too sensitive to the heat generation attenuation gradient. When the demagnetization risk is still in the early stage and the attenuation gradient is still small, the correction temperature rise rate is excessively reduced, which causes the heat generation of the motor to be suppressed too early. The temperature of the crew cabin begins to drop slowly before the demagnetization actually occurs, which also causes the control quality to deteriorate.

[0066] Therefore, the optimal The value should be a balance between the two extreme cases mentioned above—ensuring that the target temperature rise rate is smoothly reduced to a safe level before the demagnetization protection is triggered, avoiding temperature step disturbances caused by hardware-forced power limiting; and not suppressing motor heat generation too early to maintain the continuity of cabin heating.

[0067] By examining all candidates The corresponding control quality evaluation functions are compared, and the one that makes the evaluation function reach its optimal value is selected. The calibration results are then stored in the heat pump domain controller for online recall. This calibration process can be repeated at different ambient temperature calibration points, constructing a calibration system indexed by ambient temperature. The mapping table enables it to adaptively select the optimal attenuation compensation gain coefficient based on the current ambient temperature during actual operation.

[0068] The heat transport and margin constraint module 300 includes a heat source power comparison and arbitration unit 310 and a compressor speed constraint adjustment unit 320, wherein: The heat source power comparison and arbitration unit 310 receives the current maximum available heating capacity from the real-time available heating capacity estimation unit 220. Simultaneously, it calculates the theoretical heating power required to meet current comfort requirements based on the target temperature of the passenger compartment and the ambient temperature. The two power values ​​are compared, and the smaller one is selected as the actual available heat source power target. This ensures that the heat pump's heat extraction never exceeds the instantaneous heat capacity of the motor, fundamentally eliminating the risk of motor-side temperature collapse or heat pump evaporator frosting due to excessive heat extraction. The specific heat source power target is as follows: ; in: For the current maximum available heating capacity; Theoretical heating power The equivalent heat transfer coefficient of the passenger compartment is determined by the vehicle body structure and heat exchange area, and is a constant determined through actual vehicle calibration. The thermal power compensation term introduced by the current solar radiation is calculated in real time by combining the signal from the sunlight sensor located on the roof of the vehicle with the calibration coefficient; The fresh air heating power is calculated based on the current fresh air volume and the temperature difference between inside and outside. The compressor speed constraint adjustment unit 320 uses the heat source power target output by the heat source power comparison and arbitration unit 310 as the power target, and combines it with the real-time energy efficiency ratio under the current heat pump system operating conditions to accurately calculate the target speed that the compressor needs to achieve, so that all the work done by the compressor is strictly and proportionally used to transport the heat that the motor actually generates at this moment and is safe to use. Meanwhile, during the compressor speed regulation process, the current actual transport power is continuously compared with the current maximum available heating capacity to obtain a heat pump transport capacity margin that characterizes the heat pump side still has surplus transport capacity, and the heat pump transport capacity margin is output to the active loss heat generation control unit 210. ; in: This represents the actual heat power currently extracted and transported from the plate heat exchanger to the integrated evaporator core on the heat pump side. For refrigerant mass flow rate, This represents the compressor's theoretical displacement, a fixed parameter. For volumetric efficiency, a pre-calibrated two-dimensional mapping table is used to determine the efficiency based on the current engine speed and compression ratio. Then, the refrigerant enthalpy corresponding to the intake and exhaust pressures is used. ; , To obtain the absorption enthalpy and exhaust enthalpy from the refrigerant property table; The above-mentioned heat pump transport capacity margin The data is transmitted in real time to the active loss heat generation control unit 210, and then through the real-time available heating capacity estimation unit 220 and the heat source power comparison and arbitration unit 310 to obtain the heat source power target. Then, the target speed that the compressor needs to achieve is calculated, specifically: To ensure that the heat power transported by the compressor is exactly equal to the target heat source power. Substituting the target transport power into the aforementioned transport power relationship, we can solve for the target rotational speed, while considering the energy efficiency and heat transfer efficiency under the current operating conditions. Then, maintaining the same intake and exhaust parameters, the required refrigerant mass flow rate is:

[0069] Subsequently, the target rotational speed is calculated based on parameters such as intake density and volumetric efficiency: ; Meanwhile, to avoid sudden changes in target speed due to drastic changes in operating conditions, the controller... After applying a rate-of-change limit and intersecting it with the compressor's allowable upper and lower speed limits, the output is the final compressor target speed command. This command drives the compressor to operate, causing the actual handling power to automatically converge to... This ensures that all the work done by the compressor is used for the heat source power comparison and arbitration unit 310 approved by the heat source, thus achieving closed-loop control that measures input and output output.

[0070] refer to Figure 2 As shown, a thermal management method for new energy vehicles includes the following: Analyze the thermal time constant and calculate the target temperature rise rate; The direct-axis current command amplitude is calculated, and the heat pump transport capacity margin is obtained. The heat pump transport capacity margin is used as a dynamic adjustment factor for the generation of the direct-axis current command amplitude. The adaptive constraint strategy of motor heat generation power is executed, and finally the direct-axis current command amplitude is obtained. Input the direct-axis current command amplitude to the motor loss model, and the motor loss model outputs the real-time heat generation power; calculate the maximum allowable heat generation power that the permanent magnet can withstand under the current state without causing irreversible demagnetization; The demagnetization safety power margin is calculated by real-time heat generation power and maximum allowable heat generation power. Then, the heat generation attenuation gradient used to adjust the target temperature rise rate to the corrected temperature rise rate is obtained by analysis. The maximum allowable heat generation power is analyzed again until the thermal stability control state is reached. Obtain the target heat source power, calculate the target speed required for the compressor based on the target heat source power, and calculate the heat pump transport capacity margin.

[0071] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A thermal management system for new energy vehicles, characterized in that, include: The heat generation instruction generation module (100) analyzes the thermal time constant and calculates the target temperature rise rate. The motor heat and capacity feedback module (200) calculates the direct-axis current command amplitude and obtains the heat pump transport capacity margin. It uses the heat pump transport capacity margin as a dynamic adjustment factor for generating the direct-axis current command amplitude and executes the motor heat generation power adaptive constraint strategy to finally obtain the direct-axis current command amplitude. Input the direct-axis current command amplitude to the motor loss model, and the motor loss model outputs the real-time heat generation power. Calculate the maximum allowable heat output; The demagnetization safety power margin is calculated by real-time heat generation power and maximum allowable heat generation power. Then, the heat generation attenuation gradient used to adjust the target temperature rise rate to the corrected temperature rise rate is obtained. This process is repeated until a thermally stable control state is reached. The heat transport and margin constraint module (300) is used to calculate the heat pump transport capacity margin.

2. The thermal management system for new energy vehicles according to claim 1, characterized in that: The heat generation command generation module (100) includes a system thermal inertia online identification unit (110) and a target temperature rise rate decision unit (120); the motor heat and capacity feedback module (200) includes an active loss heat generation control unit (210), a real-time available heat generation estimation unit (220), and a heat generation attenuation trend calculation unit (230).

3. A thermal management system for new energy vehicles according to claim 1, characterized in that: The system thermal inertia online identification unit (110) receives the compressor speed sensor signal and the front-end module side condensing pressure sensor signal, identifies the time delay of the condensing pressure response curve relative to the step change of the compressor speed; continuously monitors the lag relationship between the condensing pressure build-up rate and the compressor speed change; and estimates a thermal time constant that reflects the overall thermal response lag. The target temperature rise rate decision unit (120) receives the deviation signal between the actual temperature and the target temperature fed back by the temperature sensor arranged in the crew cabin; and uses the thermal time constant output by the system thermal inertia online identification unit (110) as the key factor for calculation, and calculates the target temperature rise rate based on the functional relationship that automatically decays as the thermal time constant increases. The active loss heat generation control unit (210) receives the target temperature rise rate from the target temperature rise rate decision unit (120) and converts the target temperature rise rate into the target value of the total heat generation power required to control the motor. The target value for the total heat generation power is the direct-axis current command amplitude; Obtain the heat pump transport capacity margin, use the heat pump transport capacity margin as a constraint correction factor for the direct-axis current command amplitude, and execute the following adaptive constraint strategy for motor heat generation power. The final direct-axis current command amplitude is obtained; The real-time available heating capacity estimation unit (220) acquires the motor loss model and uses the motor loss model to estimate the current real-time heat generation power; in parallel, it continuously monitors the permanent magnet temperature and calculates the maximum allowable heat generation power that the permanent magnet can withstand in the current state without causing irreversible demagnetization based on a strict demagnetization protection boundary function; and defines the minimum value between the real-time heat generation power and the maximum allowable heat generation power as the current maximum available heating capacity. The heating capacity attenuation trend calculation unit (230) calculates the heating capacity attenuation gradient based on the maximum available heating capacity in the real-time available heating capacity estimation unit (220), and adjusts the target temperature rise rate to a corrected temperature rise rate based on the heating capacity attenuation gradient in the target temperature rise rate decision unit (120).

4. A thermal management system for new energy vehicles according to claim 3, characterized in that: The adaptive constraint strategy for the heat generation power of the motor is as follows: Set a tightening threshold; when the heat pump carrying capacity margin is lower than the tightening threshold, actively apply an attenuation factor above the direct-axis current command amplitude corresponding to the target temperature rise rate; When the heat pump transport capacity margin is greater than or equal to the sufficient threshold, the attenuation factor decreases proportionally with the heat pump transport capacity margin when an attenuation factor is applied.

5. A thermal management system for new energy vehicles according to claim 4, characterized in that: The tightening threshold is based on the current maximum available heating capacity output by the real-time available heating capacity estimation unit (220), and is superimposed with the heating capacity decay gradient in the heating capacity decay trend calculation unit (230), and then the margin released due to the heating demand is deducted to obtain the tightening threshold. Specifically, the tightening threshold is equal to the current maximum available heating capacity plus the heating capacity decay gradient; the ratio between the target temperature rise rate and the maximum allowable temperature rise rate of the motor is calculated; and then the product of the ratio and the current maximum available heating capacity is subtracted.

6. A thermal management system for new energy vehicles according to claim 3, characterized in that: The heat output attenuation gradient: At the current sampling time Compared with the previous sampling time Calculate the difference between the real-time heat generation power output by the motor loss model in the real-time available heat generation estimation unit (220) and the maximum allowable heat generation power; The analysis yields the demagnetization safety power margin: the current demagnetization safety power margin is equal to the current motor loss model estimate minus the current demagnetization protection boundary value; The demagnetization safety power margin at the previous moment is equal to the motor loss model estimate at the previous moment minus the demagnetization protection boundary value at the previous moment; The heating capacity decay gradient is equal to the demagnetization safety power margin at the previous moment minus the demagnetization safety power margin at the current moment, and then divided by the sampling time interval of the corresponding thermal state parameters of the heat pump system. The heating capacity attenuation gradient is obtained by dividing the periodic change of the demagnetization safety power margin by the sampling time interval of the corresponding thermal state parameters of the heat pump system.

7. A thermal management system for new energy vehicles according to claim 6, characterized in that: The corrected temperature rise rate is equal to the target temperature rise rate minus the product of the attenuation compensation gain coefficient and the heating capacity attenuation gradient.

8. A thermal management system for new energy vehicles according to claim 3, characterized in that: The heat transport and margin constraint module (300) includes a heat source power comparison and arbitration unit (310) and a compressor speed constraint adjustment unit (320). The heat source power comparison and arbitration unit (310) receives the current maximum available heat capacity from the real-time available heat capacity estimation unit (220), and calculates the theoretical heating power required to meet the current comfort requirements based on the target temperature of the crew cabin and the ambient temperature; compares the current maximum available heat capacity and the theoretical heating power, and selects the smaller one as the actual available heat source power target; The compressor speed constraint adjustment unit (320) uses the heat source power target output by the heat source power comparison and arbitration unit (310) as the power target, and calculates the target speed that the compressor needs to achieve by combining the real-time energy efficiency ratio under the current heat pump system operating conditions.

9. A thermal management system for new energy vehicles according to claim 8, characterized in that: The heat pump transport capacity margin in the active loss heat generation control unit (210) is as follows: During the compressor speed regulation process, the compressor speed constraint adjustment unit (320) continuously compares the current actual transport power with the current maximum available heating capacity to obtain the heat pump transport capacity margin.

10. A thermal management method for new energy vehicles, characterized in that, Including the following: Analyze the thermal time constant and calculate the target temperature rise rate; The direct-axis current command amplitude is calculated, and the heat pump transport capacity margin is obtained. The heat pump transport capacity margin is used as a dynamic adjustment factor for the generation of the direct-axis current command amplitude. The adaptive constraint strategy of motor heat generation power is executed, and finally the direct-axis current command amplitude is obtained. Input the direct-axis current command amplitude to the motor loss model, and the motor loss model outputs the real-time heat generation power; calculate the maximum allowable heat generation power that the permanent magnet can withstand under the current state without causing irreversible demagnetization; The demagnetization safety power margin is calculated by real-time heat generation power and maximum allowable heat generation power. Then, the heat generation attenuation gradient used to adjust the target temperature rise rate to the corrected temperature rise rate is obtained by analysis. The maximum allowable heat generation power is analyzed again until the thermal stability control state is reached. Obtain the target heat source power, calculate the target speed required for the compressor based on the target heat source power, and calculate the heat pump transport capacity margin.

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