Physical model-based ptc heating circuit modeling method, system, medium and terminal

Abstract

The application discloses a PTC heating loop modeling method and system based on a physical model, a medium, and a terminal, and belongs to the technical field of vehicle thermal management. The method first completes component modeling of PTC, a water pump, and an expansion water kettle respectively, and then integrates the three to obtain a complete PTC heating loop physical model. PTC modeling covers heating power, temperature, and pressure drop calculation, supports multiple power calculation modes, and adopts energy conservation and time sequence method to realize accurate temperature solution; the water pump balances the pressure drop in the matching loop relying on the P-Q characteristic curve and PID regulation; the expansion water kettle realizes pressure balance through differential pressure, fluid mechanics, and ideal gas state equation iteration. The application can balance model precision and operation efficiency, accurately reproduce loop dynamic operation characteristics, is suitable for various new energy vehicles such as pure electric vehicles and hybrid electric vehicles, provides reliable support for PTC heating system optimization design and control strategy calibration, and improves system control precision and power battery utilization efficiency.

Description

Technical Field

[0001] This invention belongs to the field of vehicle thermal management technology and is applicable to the modeling, calibration and development of heating systems for various types of vehicles such as pure electric vehicles and hybrid electric vehicles. Specifically, it involves a physical model-based PTC heating circuit modeling method, system and medium, and terminal. Background Technology

[0002] With the rapid development of the new energy vehicle industry, electric vehicles have gradually become the mainstream of the automotive industry due to their energy-saving and environmental protection advantages. Compared with traditional fuel vehicles, the energy supply mode of electric vehicles has undergone fundamental changes, with the power battery serving as the sole energy source for the entire vehicle.

[0003] In the energy supply system of electric vehicles, PTC (Positive Temperature Coefficient) heating elements play a crucial role in ensuring passenger cabin comfort and the efficient and safe operation of the power battery. A PTC heating element is a self-resetting thermistor element with outstanding characteristics such as high heating efficiency, stable operation, and reliable performance. Its working principle is as follows: when current passes through the PTC heating element, the element generates a thermal effect, thereby increasing its surface temperature and ultimately heating the vehicle's coolant.

[0004] Compared to traditional electric heaters, the PTC water heaters used in electric vehicles have significant technological advantages, primarily in power self-regulation and temperature stability. In low-temperature environments, the activity of the power battery decreases significantly, and the efficiency of the motor and electronic control system is also affected. At this time, the PTC water heater can precisely control its heating power and temperature by adjusting the input current, ensuring that the vehicle's coolant remains within a suitable operating temperature range. This effectively guarantees the normal operation of core components such as the motor and power battery, preventing performance degradation or malfunctions caused by low temperatures. Simultaneously, the PTC water heater has high heating efficiency, capable of heating the coolant to the set temperature in a short time, significantly shortening the vehicle's preheating time. This improves passenger comfort and further ensures the safety of vehicle starts and operation in low temperatures.

[0005] Currently, there is still room for optimization in the modeling methods of PTC heating circuits. Existing modeling methods cannot balance model accuracy and running speed, and cannot accurately and efficiently simulate the working process of PTC water heaters and the energy transfer characteristics of heating circuits. This may affect the control accuracy of PTC heating systems, which is not conducive to the efficient utilization of power battery energy and the reliable protection of core components. Summary of the Invention

[0006] The purpose of this invention is to provide a physical model-based PTC heating circuit modeling method, system, medium, and terminal to address the shortcomings of existing technologies and provide strong support for the optimized design of PTC heating systems in electric vehicles.

[0007] To achieve the objectives of this invention, the technical solution provided by this invention is as follows: First aspect This invention provides a physical model-based method for modeling PTC heating circuits, comprising the following steps: Step S1: Perform PTC modeling to obtain the PTC component model; Step S2: Model the water pump to obtain the water pump component model; Step S3: Model the expansion kettle to obtain the expansion kettle component model; Step S4: Integrate the PTC component model, water pump component model, and expansion tank component model to form a complete physical model of the PTC heating circuit.

[0008] Second aspect This invention provides a physical model-based PTC heating circuit modeling system for executing the physical model-based PTC heating circuit modeling method as described in any one of claims 1-4, characterized in that it includes the following units: The PTC modeling unit is used to perform PTC modeling and obtain PTC component models. The pump modeling unit is used to model pumps and obtain pump component models. The expansion kettle modeling unit is used to model the expansion kettle and obtain the expansion kettle component model; The integration unit is used to integrate the PTC component model, the water pump component model, and the expansion kettle component model to form a complete physical model of the PTC heating circuit.

[0009] Third aspect The present invention provides a computer-readable storage medium having a computer program / instruction stored thereon, which, when executed by a processor, implements the physical model-based PTC heating circuit modeling method described above.

[0010] Fourth aspect The present invention provides an electronic terminal, including a processor and a memory, wherein the memory stores a computer program / instruction, which, when executed by the processor, implements the physical model-based PTC heating circuit modeling method.

[0011] Compared with the prior art, the beneficial effects of the present invention are as follows: This invention adopts a method of independent modeling and re-integration of components to accurately dissect the core physical characteristics of PTC, water pump, and expansion tank. This not only ensures the simulation accuracy of the model for energy transfer, pressure balance, and flow regulation in the heating circuit, but also simplifies the calculation logic, improves the model's running speed, and solves the problem of balancing accuracy and efficiency in traditional modeling.

[0012] In addition, the modeling covers three-dimensional calculations of power, temperature, and pressure drop, and supports multiple power calculation modes such as constant power, PID control, and data interpolation. Temperature calculation adopts a combination of time series method and energy conservation, and pressure drop is based on interpolation of measured data, which can accurately restore the real working state of PTC under different inlet water temperature, flow rate, and voltage.

[0013] In addition, the water pump model relies on the PQ characteristic curve and PID control to accurately match the loop pressure drop balance with the target flow rate; the expansion kettle calculates the pressure balance through differential pressure, fluid mechanics, and ideal gas law iterative calculation, realistically simulating the system pressure stabilization process and fully reproducing the dynamic operating characteristics of the heating loop.

[0014] In addition, this invention is applicable to PTC heating systems of various types of new energy vehicles, including pure electric and hybrid vehicles, providing reliable support for system optimization design and control strategy calibration, improving the control accuracy of PTC heating systems, and helping to achieve efficient utilization of power batteries and reliable protection of core components. Attached Figure Description

[0015] Figure 1 A schematic diagram of the PTC heating circuit modeling method based on a physical model provided in this embodiment of the invention; Figure 2 This is a schematic diagram of the overall structure of the PTC heating circuit provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of a PTC provided in an embodiment of the present invention; Figure 4 This is a schematic diagram of an expansion tank provided in an embodiment of the present invention; Figure 5 This is a schematic diagram of the calculation logic for the expansion kettle provided in an embodiment of the present invention. Detailed Implementation

[0016] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0017] It should be noted that the acquisition of data and collection of information in this application are legal, compliant, or obtained with the consent of the subject of the data collection.

[0018] Figure 2 This is a schematic diagram of the overall PTC heating circuit provided in this embodiment of the invention. The circuit consists of three core components: a PTC heating module, a water pump module, and an expansion tank. These modules work closely together and interact with each other through real-time transmission of flow, pressure, and temperature signals. The PTC module, as the key unit for heating control, is responsible for determining and selecting the heating power requirement based on the system temperature signal, while simultaneously calculating the temperature change of the coolant as it flows through and analyzing the pipeline pressure drop. The water pump module, as the power core of the circuit, dynamically adjusts its output pressure rise based on the total system pressure drop feedback to match the sum of pressure losses generated by all components in the circuit, ensuring stable coolant flow. The expansion tank performs system pressure balancing and media compensation functions, absorbing or replenishing coolant to buffer volume fluctuations caused by temperature changes, thereby maintaining stable circuit pressure and ensuring long-term reliable system operation. These three components work together to form a highly efficient and stable closed-loop water system.

[0019] like Figure 1 As shown, this invention provides a physical model-based method for modeling PTC heating circuits, comprising the following steps: Step S1: Perform PTC modeling to obtain the PTC component model; Figure 3 This is a schematic diagram of the PTC provided in this embodiment of the invention. In the simulation modeling process, to accurately characterize the thermodynamic properties of the PTC heater, it is simplified into a chamber structure with a certain volume. Based on the following core assumptions: during the heating process, the key physical properties of the coolant flowing through the PTC, such as density and specific heat capacity, are considered constant, ensuring computational efficiency and model stability. The core calculation principle of the model follows the law of conservation of energy, that is, the heating power of the PTC is equal to the heat absorbed by the coolant during its flow through the chamber, from which the outlet temperature of the coolant can be calculated. The specific derivation, discretization method, and solution steps of this energy balance equation have been elaborated in detail in the aforementioned technical solution and will not be repeated here.

[0020] This step includes several parts: heating power calculation, temperature calculation, and pressure drop calculation. For the calculation of heating power, one of the following three methods is used: (1) Fixed heating power; (2) PID control is performed based on the difference between the target temperature and the actual temperature; (3) Obtained based on data interpolation; the calculation formula is as follows: ; ; ; ; ; In the formula: This is the proportionality coefficient corresponding to the PTC inlet water temperature; This is the proportional coefficient corresponding to the PTC inlet flow; This is the proportional coefficient corresponding to the PTC input voltage; PTC reference power; The PTC heating power corresponding to the inlet water temperature; The PTC heating power corresponding to the inlet flow rate; The PTC heating power corresponding to the input voltage; The PTC heating power is calculated under different inlet conditions; The PTC power calculated under different inlet conditions; For PTC efficiency; For temperature calculation, the following method is used: Initialization: Set the PTC as a cavity with volume V and the coolant density throughout the heating process. Heat capacity Keeping them unchanged, the original coolant temperature and volume are T0 and V0 respectively, and the inlet water temperature and inlet volume are T. 10 The outlet water temperature and outlet volume are T2 and V1, respectively; Calculation logic: The PTC heating power is first used to heat the inlet coolant. Then, the heated inlet coolant is mixed with the original PTC coolant to calculate the PTC outlet coolant temperature. The inlet water temperature after heating is T1. Based on the principle of energy conservation, the following formula is established: ; ； ； ； ； The time series method is used for modeling, calculation and solution, that is, T0 is the outlet temperature at step t-1, and V1 is the inlet flow rate m obtained by integrating with time; For pressure drop calculation, it is obtained by interpolation based on PTC inlet flow-pressure drop data.

[0021] Step S2: Model the water pump to obtain the water pump component model; In this step, the water pump controls the outlet flow rate by changing the speed of the pump motor; flow resistance losses and temperature changes are not considered in the calculation. The core characteristic curve of the water pump is the PQ curve, which is responsible for maintaining the pressure drop balance of the entire loop. The specific modeling logic is as follows: First, the relationship between flow rate, rotational speed and pump pressure rise was established based on the experimental dataset; Secondly, calculate the total pressure drop of the entire heating circuit; Finally, based on the numerical matching relationship between the pump pressure rise and the total pressure drop of the heating circuit, the target flow rate is gradually approximated through PID control, and the pump outlet flow rate is finally obtained.

[0022] Step S3: Model the expansion kettle to obtain the expansion kettle component model; Figure 4 This is a schematic diagram of an expansion tank provided in an embodiment of the present invention. In simulation modeling, the physical structure of the expansion tank is equivalent to a container model containing a gas-liquid two-phase region, as shown in the attached figure. The core and difficulty of its modeling lies in the dynamic calculation of system pressure, which plays a decisive role in the pressure stability of the entire loop. The specific pressure regulation mechanism is as follows: When the loop pressure fluctuates, the tank inlet pressure P1 is a dynamically changing input. By changing the flow rate of coolant flowing into or out of the tank, the liquid level inside the tank rises or falls, thereby changing the volume of the upper closed air cavity. This part of the air is regarded as an ideal gas, and its pressure changes inversely proportionally with the volume change. This change in gas pressure is immediately fed back to the tank outlet pressure P2 and acts on the entire loop until the inlet pressure P1 and the outlet pressure P2 reach equilibrium in a new state, thereby achieving the regulation and stable maintenance of system pressure.

[0023] In this step, the expansion tank is the pressure stabilizing component in the entire system, and the key lies in pressure calculation. During the pressure adjustment process of the expansion tank, the inlet pressure P1 is constantly changing. By adjusting the liquid flow rate in the expansion tank, the volume of air in the expansion tank is changed, thereby changing the gas pressure, until the inlet pressure P1 and the outlet pressure P2 are equal. Figure 5This is a schematic diagram of the calculation logic for the expansion tank provided in this embodiment of the invention. The dynamic pressure calculation of the expansion tank is the core link of the system simulation, and the key lies in the pressure balance mechanism of the gas and liquid phases. First, the pressure difference between the pressure at the inlet of the expansion tank and the initial pressure of the gas inside the tank is calculated. Second, the magnitude of the pressure difference is determined. When the pressure difference is greater than 0, that is, the pressure at the inlet of the expansion tank is greater than the initial pressure of the gas inside the tank, the liquid level of the coolant inside the tank rises, and the volume occupied by the gas decreases. The new pressure and volume of the gas inside the expansion tank are calculated based on the changed gas volume and the ideal state equation. When the pressure difference is equal to 0, that is, the pressure at the inlet of the expansion tank is equal to the initial pressure of the gas inside the tank, the liquid level of the coolant inside the tank remains unchanged, and the volume and pressure occupied by the gas maintain their initial values. When the pressure difference is less than 0, that is, the pressure at the inlet of the expansion tank is less than the initial pressure of the gas inside the tank, the liquid level of the coolant inside the tank drops, and the volume occupied by the gas increases. Similarly, the new pressure and volume of the gas inside the expansion tank are calculated based on the changed gas volume and the ideal state equation. The detailed calculation formulas and methods have been described in detail in the aforementioned technical solutions and will not be repeated here. The calculations are iterated continuously until the simulation requirements are met.

[0024] The specific steps for pressure calculation are as follows: Step S3.1: Calculate the inlet pressure P1 and the air pressure P in the expansion tank. g The difference ; ; Step S3.2: Based on pressure difference The change in liquid flow rate in the expansion tank was calculated using fluid dynamics formulas. The formula is as follows: ; ; ; in, ρ The density of the coolant; For flow coefficient; λ is the cross-sectional area of ​​the orifice; λ is the current flow coefficient. Take 100; The hydraulic diameter; Kinematic viscosity; Step S3.3: Based on flow rate changes and time step t Calculate the volume change of the air cavity inside the expansion tank. : ; The air cavity volume is then updated using the following formula: ; in: For time step; The volume of air in the expanded kettle after the change; This represents the initial volume of air in the expansion tank; + indicates that the liquid level has dropped, - indicates that the liquid level has risen. Step S3.4: Update the air volume Substituting into the ideal gas law, the changed gas pressure Pg is calculated. new ; Step S3.5: Repeat the above steps to continuously update Pg. new And compare P1 with Pg new When P1 = Pg new When the pressure in the kettle reaches equilibrium, the iteration stops.

[0025] Step S4: Integrate the PTC component model, water pump component model, and expansion tank component model to form a complete physical model of the PTC heating circuit.

[0026] This embodiment also provides a physical model-based PTC heating circuit modeling system for executing the physical model-based PTC heating circuit modeling method, including the following units: The PTC modeling unit is used to perform PTC modeling and obtain PTC component models. The pump modeling unit is used to model pumps and obtain pump component models. The expansion kettle modeling unit is used to model the expansion kettle and obtain the expansion kettle component model; The integration unit is used to integrate the PTC component model, the water pump component model, and the expansion kettle component model to form a complete physical model of the PTC heating circuit.

[0027] The PTC modeling unit includes several parts during execution, such as heating power calculation, temperature calculation, and pressure drop calculation. For the calculation of heating power, one of the following three methods is used: (1) Fixed heating power; (2) PID control is performed based on the difference between the target temperature and the actual temperature; (3) Obtained based on data interpolation; the calculation formula is as follows: ; ; ; ; ; In the formula: This is the proportionality coefficient corresponding to the PTC inlet water temperature; This is the proportional coefficient corresponding to the PTC inlet flow; This is the proportional coefficient corresponding to the PTC input voltage; PTC reference power; The PTC heating power corresponding to the inlet water temperature; The PTC heating power corresponding to the inlet flow rate; The PTC heating power corresponding to the input voltage; The PTC heating power is calculated under different inlet conditions; The PTC power calculated under different inlet conditions; For PTC efficiency; For temperature calculation, the following method is used: Initialization: Set the PTC as a cavity with volume V and the coolant density throughout the heating process. Heat capacity Keeping them unchanged, the original coolant temperature and volume are T0 and V0 respectively, and the inlet water temperature and inlet volume are T. 10 The outlet water temperature and outlet volume are T2 and V1, respectively; Calculation logic: The PTC heating power is first used to heat the inlet coolant. Then, the heated inlet coolant is mixed with the original PTC coolant to calculate the PTC outlet coolant temperature. The inlet water temperature after heating is T1. Based on the principle of energy conservation, the following formula is established: ; ； ； ； ； The time series method is used for modeling, calculation and solution, that is, T0 is the outlet temperature at step t-1, and V1 is the inlet flow rate m obtained by integrating with time; For pressure drop calculation, it is obtained by interpolation based on PTC inlet flow-pressure drop data.

[0028] When the water pump modeling unit is executed, the water pump controls the outlet flow rate by changing the speed of the water pump motor. Flow resistance losses and temperature changes are not considered in the calculation. The core characteristic curve of the water pump is the PQ curve, which is responsible for maintaining the pressure drop balance of the entire loop. The specific modeling logic is as follows: First, the relationship between flow rate, rotational speed and pump pressure rise was established based on the experimental dataset; Secondly, calculate the total pressure drop of the entire heating circuit; Finally, based on the numerical matching relationship between the pump pressure rise and the total pressure drop of the heating circuit, the target flow rate is gradually approximated through PID control, and the pump outlet flow rate is finally obtained.

[0029] When the expansion tank modeling unit is executed, the expansion tank is the pressure stabilizing component in the entire system, and the key lies in pressure calculation. During the pressure regulation process of the expansion tank, the inlet pressure P1 is constantly changing. By adjusting the liquid flow rate in the expansion tank, the volume of air in the expansion tank is changed, thereby changing the gas pressure, until the inlet pressure P1 and the outlet pressure P2 are equal. The steps for pressure calculation are as follows: Step S3.1: Calculate the inlet pressure P1 and the air pressure P in the expansion tank. g The difference ; ; Step S3.2: Based on pressure difference The change in liquid flow rate in the expansion tank was calculated using fluid dynamics formulas. The formula is as follows: ; ; ; in, ρ The density of the coolant; For flow coefficient; λ is the cross-sectional area of ​​the orifice; λ is the current flow coefficient. Take 100; The hydraulic diameter; Kinematic viscosity; Step S3.3: Based on flow rate changes and time step t Calculate the volume change of the air cavity inside the expansion tank. : ; The air cavity volume is then updated using the following formula: ; in: For time step; The volume of air in the expanded kettle after the change; This represents the initial volume of air in the expansion tank; + indicates that the liquid level has dropped, - indicates that the liquid level has risen. Step S3.4: Update the air volume Substituting into the ideal gas law, the changed gas pressure Pg is calculated. new; Step S3.5: Repeat the above steps to continuously update Pg. new And compare P1 with Pg new When P1 = Pg new When the pressure in the kettle reaches equilibrium, the iteration stops.

[0030] In addition, this embodiment also provides a computer-readable storage medium storing a computer program / instruction thereon, which, when executed by a processor, implements the physical model-based PTC heating circuit modeling method described above.

[0031] In addition, this embodiment also provides an electronic terminal, including a processor and a memory, wherein the memory stores a computer program / instruction, which, when executed by the processor, implements the physical model-based PTC heating circuit modeling method.

[0032] Finally, it should be noted that the above embodiments are merely illustrative and explanatory of the present invention, and are not intended to limit the present invention to the scope of the described embodiments. Furthermore, those skilled in the art will understand that the present invention is not limited to the above embodiments, and many more variations and modifications can be made based on the teachings of the present invention, all of which fall within the scope of protection claimed by the present invention.

Claims

1. A method for modeling a PTC heating circuit based on a physical model, characterized in that, Includes the following steps: Step S1: Perform PTC modeling to obtain the PTC component model; Step S2: Model the water pump to obtain the water pump component model; Step S3: Model the expansion kettle to obtain the expansion kettle component model; Step S4: Integrate the PTC component model, water pump component model, and expansion tank component model to form a complete physical model of the PTC heating circuit.

2. The method for modeling a PTC heating circuit based on a physical model according to claim 1, characterized in that, Step S1 includes several parts: heating power calculation, temperature calculation, and pressure drop calculation. For the calculation of heating power, one of the following three methods is used: (1) Fixed heating power; (2) PID control is performed based on the difference between the target temperature and the actual temperature; (3) Obtained based on data interpolation; the calculation formula is as follows: ； ； ； ； ； In the formula: This is the proportionality coefficient corresponding to the PTC inlet water temperature; This is the proportional coefficient corresponding to the PTC inlet flow; This is the proportional coefficient corresponding to the PTC input voltage; PTC reference power; The PTC heating power corresponding to the inlet water temperature; The PTC heating power corresponding to the inlet flow rate; The PTC heating power corresponding to the input voltage; The PTC heating power is calculated under different inlet conditions; The PTC power calculated under different inlet conditions; For PTC efficiency; For temperature calculation, the following method is used: Initialization: Set the PTC as a cavity with volume V and the coolant density throughout the heating process. Heat capacity Keeping them unchanged, the original coolant temperature and volume are T0 and V0 respectively, and the inlet water temperature and inlet volume are T. 10 The outlet water temperature and outlet volume are T2 and V1, respectively; Calculation logic: The PTC heating power is first used to heat the inlet coolant. Then, the heated inlet coolant is mixed with the original PTC coolant to calculate the PTC outlet coolant temperature. The inlet water temperature after heating is T1. Based on the principle of energy conservation, the following formula is established: ； ； ； ； ； The time series method is used for modeling, calculation and solution, that is, T0 is the outlet temperature at step t-1, and V1 is the inlet flow rate m obtained by integrating with time; For pressure drop calculation, it is obtained by interpolation based on PTC inlet flow-pressure drop data.

3. The method for modeling a PTC heating circuit based on a physical model according to claim 2, characterized in that, In step S2, the water pump controls the outlet flow rate by changing the speed of the pump motor. Flow resistance losses and temperature changes are not considered in the calculation. The core characteristic curve of the water pump is the PQ curve, which is responsible for maintaining the pressure drop balance of the entire loop. The specific modeling logic is as follows: First, the relationship between flow rate, rotational speed and pump pressure rise was established based on the experimental dataset; Secondly, calculate the total pressure drop of the entire heating circuit; Finally, based on the numerical matching relationship between the pump pressure rise and the total pressure drop of the heating circuit, the target flow rate is gradually approximated through PID control, and the pump outlet flow rate is finally obtained.

4. The method for modeling a PTC heating circuit based on a physical model according to claim 3, characterized in that, In step S3, the expansion tank is the pressure stabilizing component in the entire system, and the key lies in pressure calculation. During the pressure adjustment process of the expansion tank, the inlet pressure P1 is constantly changing. By adjusting the liquid flow rate in the expansion tank, the volume of air in the expansion tank is changed, thereby changing the gas pressure, until the inlet pressure P1 and the outlet pressure P2 are equal. The steps for pressure calculation are as follows: Step S3.1: Calculate the inlet pressure P1 and the air pressure P in the expansion tank. g The difference ; ； Step S3.2: Based on pressure difference The change in liquid flow rate in the expansion tank was calculated using fluid dynamics formulas. The formula is as follows: ； ； ； in, ρ The density of the coolant; For flow coefficient; λ is the cross-sectional area of ​​the orifice; λ is the current flow coefficient. Take 100; The hydraulic diameter; Kinematic viscosity; Step S3.3: Based on flow rate changes and time step t Calculate the volume change of the air cavity inside the expansion tank. : ； The air cavity volume is then updated using the following formula: ； in: For time step; The volume of air in the expanded kettle after the change; This represents the initial volume of air in the expansion tank; + indicates that the liquid level has dropped, - indicates that the liquid level has risen. Step S3.4: Update the air volume Substituting into the ideal gas law, the changed gas pressure Pg is calculated. new ; Step S3.5: Repeat the above steps to continuously update Pg. new And compare P1 with Pg new When P1 = Pg new When the pressure in the kettle reaches equilibrium, the iteration stops.

5. A physical model-based PTC heating circuit modeling system, used to execute the physical model-based PTC heating circuit modeling method as described in any one of claims 1-4, characterized in that, Includes the following units: The PTC modeling unit is used to perform PTC modeling and obtain PTC component models. The pump modeling unit is used to model pumps and obtain pump component models. The expansion kettle modeling unit is used to model the expansion kettle and obtain the expansion kettle component model; An integration unit is used to integrate the PTC component model, the water pump component model, and the expansion kettle component model to form a complete physical model of the PTC heating circuit.

6. The PTC heating circuit modeling system based on a physical model according to claim 5, characterized in that, When the PTC modeling unit is executed, it includes several parts: heating power calculation, temperature calculation, and pressure drop calculation. For the calculation of heating power, one of the following three methods is used: (1) Fixed heating power; (2) PID control is performed based on the difference between the target temperature and the actual temperature; (3) Obtained based on data interpolation; the calculation formula is as follows: ； ； ； ； ； In the formula: This is the proportionality coefficient corresponding to the PTC inlet water temperature; This is the proportional coefficient corresponding to the PTC inlet flow; This is the proportional coefficient corresponding to the PTC input voltage; PTC reference power; The PTC heating power corresponding to the inlet water temperature; The PTC heating power corresponding to the inlet flow rate; The PTC heating power corresponding to the input voltage; The PTC heating power is calculated under different inlet conditions; The PTC power calculated under different inlet conditions; For PTC efficiency; For temperature calculation, the following method is used: Initialization: Set the PTC as a cavity with volume V and the coolant density throughout the heating process. Heat capacity Keeping them unchanged, the original coolant temperature and volume are T0 and V0 respectively, and the inlet water temperature and inlet volume are T. 10 The outlet water temperature and outlet volume are T2 and V1, respectively; Calculation logic: The PTC heating power is first used to heat the inlet coolant. Then, the heated inlet coolant is mixed with the original PTC coolant to calculate the PTC outlet coolant temperature. The inlet water temperature after heating is T1. Based on the principle of energy conservation, the following formula is established: ； ； ； ； ； The time series method is used for modeling, calculation and solution, that is, T0 is the outlet temperature at step t-1, and V1 is the inlet flow rate m obtained by integrating with time; For pressure drop calculation, it is obtained by interpolation based on PTC inlet flow-pressure drop data.

7. A PTC heating circuit modeling system based on a physical model according to claim 6, characterized in that, When the pump modeling unit is executed, the pump controls the outlet flow rate by changing the speed of the pump motor. Flow resistance losses and temperature changes are not considered in the calculation. The core characteristic curve of the pump is the PQ curve, which is responsible for maintaining the pressure drop balance of the entire loop. The specific modeling logic is as follows: First, the relationship between flow rate, rotational speed and pump pressure rise was established based on the experimental dataset; Secondly, calculate the total pressure drop of the entire heating circuit; Finally, based on the numerical matching relationship between the pump pressure rise and the total pressure drop of the heating circuit, the target flow rate is gradually approximated through PID control, and the pump outlet flow rate is finally obtained.

8. A PTC heating circuit modeling system based on a physical model according to claim 7, characterized in that, When the expansion tank modeling unit is executed, the expansion tank is the pressure stabilizing component in the entire system, and the key lies in pressure calculation. During the pressure regulation process of the expansion tank, the inlet pressure P1 is constantly changing. By adjusting the liquid flow rate in the expansion tank, the volume of air in the expansion tank is changed, thereby changing the gas pressure, until the inlet pressure P1 and the outlet pressure P2 are equal. The steps for pressure calculation are as follows: Step S3.1: Calculate the inlet pressure P1 and the air pressure P in the expansion tank. g The difference ; ； Step S3.2: Based on pressure difference The change in liquid flow rate in the expansion tank was calculated using fluid dynamics formulas. The formula is as follows: ； ； ； in, ρ The density of the coolant; For flow coefficient; λ is the cross-sectional area of ​​the orifice; λ is the current flow coefficient. Take 100; The hydraulic diameter; Kinematic viscosity; Step S3.3: Based on flow rate changes and time step t Calculate the volume change of the air cavity inside the expansion tank. : ； The air cavity volume is then updated using the following formula: ； in: For time step; The volume of air in the expanded kettle after the change; This represents the initial volume of air in the expansion tank; + indicates that the liquid level has dropped, - indicates that the liquid level has risen. Step S3.4: Update the air volume Substituting into the ideal gas law, the changed gas pressure Pg is calculated. new ; Step S3.5: Repeat the above steps to continuously update Pg. new And compare P1 with Pg new When P1 = Pg new When the pressure in the kettle reaches equilibrium, the iteration stops.

9. A computer-readable storage medium having a computer program / instructions stored thereon, characterized in that, When the computer program / instruction is executed by the processor, it implements the physical model-based PTC heating circuit modeling method as described in any one of claims 1-4.

10. An electronic terminal, characterized in that, It includes a processor and a memory, wherein the memory stores a computer program / instruction that, when executed by the processor, implements the physical model-based PTC heating circuit modeling method as described in any one of claims 1-4.

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