Automobile pump valve heat management system control method based on variable structure algorithm

Abstract

The invention provides an automobile pump valve heat management system control method based on a variable structure algorithm, an automobile pump valve heat management system internally comprises a variable structure controller, a motor, a PID controller, a gear pump and a speed regulating valve which are electrically connected in sequence, and cooling liquid is transmitted to a valve position of a regulating valve through the gear pump to flow out. S2, controlling the starting motor to run at a low speed through a PID controller, detecting and judging whether the liquid flow at the valve is within a first preset adjusting range or not: if so, controlling the motor to perform linear acceleration through the PID controller, and returning to the step S1; if not, controlling the motor to keep the real-time rotating speed through the PID controller and turning to the step S2; and S2, the real-time temperature of the motor is detected, the temperature difference value between the real-time temperature and the preset target temperature is calculated, and the valve opening degree of the speed adjusting valve is controlled and adjusted through the variable structure controller based on the temperature difference value. The method has the beneficial effects that the stability of the automobile pump valve heat management system can be improved, and high-precision control is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of automobile pump and valve control modes, and in particular to a control method for an automobile pump and valve thermal management system based on a variable structure algorithm. Background Art

[0002] Thermal management systems for new energy vehicles typically include multiple coolant circuits, heat exchangers, pumps, and valves to maintain optimal temperatures under varying driving conditions. Typically, pumps circulate the coolant, while valves control the flow path and volume to achieve heating or cooling. Traditional solutions can cause parameter misalignment during pump startup and low-speed operation due to the system's slow time-varying characteristics and model instability caused by nonlinear changes in medium temperature, viscosity, and leakage over time.

[0003] Common pump and valve control strategies include threshold-based control and PID control (proportional control). Threshold-based control, also commonly referred to as on-off control, triggers an action when temperature or other parameters reach a specific threshold. This simple control method is suitable for static or low-dynamic scenarios. However, due to its instability, poor anti-disturbance capabilities, and high component wear from repeated switching, its limitations are becoming increasingly apparent in thermal management systems for new energy vehicles.

[0004] PID control is precise and accurate, providing precise temperature regulation. It has dynamic response capabilities and can adapt to dynamic changes, such as changes in driving speed or ambient temperature fluctuations, by adjusting the coolant flow through real-time feedback. It is cost-effective and versatile, with low computational requirements and hardware costs, making it suitable for resource constraints in automotive applications.

[0005] However, PID control also has the following defects: 1. Parameter complexity: PID control requires precise adjustment of proportional, integral, and differential parameters. Incorrect adjustment can lead to temperature fluctuations or slow response, which can cause system oscillation and affect performance. 2. Limited handling of nonlinear systems: Thermal management systems may exhibit nonlinear behavior, such as changes in coolant flow resistance with temperature. PID control, as a linear method, may not be able to effectively handle these nonlinearities, resulting in reduced control accuracy. 3. Noise sensitivity: Temperature measurement may contain noise, and PID control, especially the derivative term, may amplify this noise, resulting in unstable control. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to improve the stability of the automotive pump and valve thermal management system and achieve high-precision control. In order to overcome the defects of the above-mentioned existing technology (or related technology), the present invention provides a control method of the automotive pump and valve thermal management system based on a variable structure algorithm.

[0007] The present invention provides a control method for an automobile pump and valve thermal management system based on a variable structure algorithm. The automobile pump and valve thermal management system includes a variable structure controller, a motor, a PID controller, and a gear pump that are electrically connected in sequence. The output port of the gear pump is connected to the input port of a speed regulating valve. The variable structure controller is also electrically connected to the speed regulating valve. Coolant is transmitted through the gear pump to the valve of the regulating valve for outflow. The control method for the automobile pump and valve thermal management system includes the following steps: Step S1: Start the motor to run at a low speed by controlling the PID controller, and detect and determine whether the liquid flow at the valve of the speed regulating valve is within a first preset adjustment range: If yes, the motor is controlled by the PID controller to perform linear acceleration, and then the process returns to step S1; If not, the PID controller controls the motor to maintain the current real-time speed and goes to step S2; Step S2 , detecting the real-time temperature of the motor and calculating the temperature difference between the real-time temperature and a preset target temperature, and controlling and adjusting the valve opening of the speed regulating valve through the variable structure controller based on the temperature difference.

[0008] Compared with the prior art, the control method of the automotive pump and valve thermal management system based on the variable structure algorithm in this application has the following advantages: In the present application, a variable structure controller is used to avoid the nonlinear characteristics and motor control hysteresis caused by the gear pump speed dead zone and the low self-priming ability of the hydraulic pump when the motor is started and at low power speed; when the motor is running at a higher power, a PID controller is used to control the acceleration and deceleration of the motor, so that the gear pump and the speed control valve can achieve the purpose of coarse adjustment; secondly, after the motor completes the coarse adjustment, the valve control system has a better response speed than the motor control, and the speed control valve is feedback controlled by the variable structure controller, so as to achieve the purpose of fine adjustment and improve the stability of the automobile pump and valve thermal management system; finally, high-precision control of the motor and the speed control valve is achieved by combining sensor data such as speed, temperature and flow with the hybrid control strategy of steps S1 and S2.

[0009] In a possible implementation, step S2 includes: Step S21, detecting the real-time temperature of the motor and calculating the temperature difference between the real-time temperature and the preset target temperature; Step S22: determine whether the real-time temperature reaches the target temperature: If yes, the variable structure controller controls the speed regulating valve to maintain the valve opening at the current moment; If not, go to step S23; Step S23: determine whether the temperature difference is within a second preset adjustment range: If so, the variable structure controller controls the speed regulating valve to adjust the valve opening, and then returns to step S23; If not, go to step S24; Step S24, determining whether the target temperature is greater than the real-time temperature: If yes, the motor is controlled by the PID controller to perform linear acceleration, and then the process returns to step S21; If not, the motor is controlled by the PID controller to perform linear deceleration, and then the process returns to step S21.

[0010] Compared with the existing technology, the above technical solution can realize multi-level adjustment control of temperature difference judgment and opening maintenance, adjustment range judgment, and motor linear speed regulation, so as to realize refined temperature control and avoid system fluctuations caused by frequent adjustment of the speed control valve. At the same time, when the temperature does not meet the standard, the judgment of the second preset adjustment range is introduced to distinguish between small deviations and significant deviations, and the speed control valve adjustment or motor speed regulation is selected in a targeted manner to enhance the system's anti-interference ability.

[0011] In a possible implementation manner, after controlling the speed regulating valve to maintain the valve opening at the current moment through the variable structure controller in step S22, the method further includes: Determine whether the temperature difference is within a third preset adjustment range: If so, exit; If not, go to step S24.

[0012] Compared with the existing technology, the above technical solution can avoid triggering unnecessary control actions due to slight temperature fluctuations by adding a third preset adjustment range as an exit condition, thereby reducing system energy consumption and component wear. At the same time, it further verifies temperature stability on the basis of maintaining the valve opening, ensuring that the control process only executes subsequent operations when it is fully met or significantly deviates, thereby improving system reliability.

[0013] In a possible implementation, after determining that the temperature difference is within the third preset adjustment range, the method further includes: Determine whether an external alarm signal or shutdown signal is received: If not, the variable structure controller controls the speed regulating valve to maintain the valve opening at the current moment; If so, the motor is turned off by the PID controller and the speed regulating valve is reset by the variable structure controller.

[0014] Compared with the existing technology, the above technical solution can prevent overheating or fault spread through the motor shutdown and valve reset mechanism triggered by external signals, namely alarm signals or shutdown signals, thereby improving system safety. At the same time, it combines active detection and external instructions to achieve rapid response in emergency situations, reduce the need for manual intervention, and meet the design requirements of intelligent control systems.

[0015] In a possible implementation, in step S1, the inlet pressure and outlet pressure of the speed control valve are detected, and the liquid flow rate is obtained based on the inlet pressure, the outlet pressure, the flow rate of the speed control valve, and the liquid density of the liquid flowing through the valve port of the speed control valve.

[0016] Compared with the existing technology, the above technical solution can eliminate the influence of single sensor error and improve the accuracy of liquid flow calculation based on multi-parameter joint calculation of inlet pressure, outlet pressure, liquid density and flow rate. At the same time, it can directly deduce the liquid flow through dynamic pressure changes, reduce the delay problem of traditional flow meters, and provide high-efficiency data support for subsequent control decisions.

[0017] In a possible implementation, in step S1, the liquid flow rate is obtained by the following calculation formula: in, represents the liquid flow rate; It represents the flow coefficient; represents the throughflow rate; represents the density of the liquid; represents the inlet pressure; Indicates the outlet pressure.

[0018] In a possible implementation, in step S2, the valve opening is obtained according to the inlet pressure, the outlet pressure, the liquid density, and the effective cross-sectional area of ​​the valve port of the speed control valve.

[0019] Compared with the existing technology, the above technical solution can combine the formulaic calculation of the effective cross-sectional area of ​​the valve port and the pressure difference to achieve a quantitative correlation between the valve opening and the cooling demand, avoiding the control deviation caused by empirical parameters. At the same time, through the dynamic input of liquid density and pressure parameters, the valve control can automatically adapt to different coolant types or ambient pressure changes, expanding the system application scenarios.

[0020] In a possible implementation, in step S2, the valve opening is obtained by the following calculation formula: in, Indicates the effective cross-sectional area of ​​the valve port; Indicates the valve opening; represents the density of the liquid; represents the inlet pressure; Indicates the outlet pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a schematic diagram of the structure of the automotive pump and valve thermal management system of the present invention; Figure 2 is a flowchart of step S1 of the present invention; Figure 3 It is a control flow chart of the present invention. DETAILED DESCRIPTION

[0022] First, those skilled in the art should understand that these embodiments are merely used to explain the technical principles of the embodiments of the present application and are not intended to limit the scope of protection of the embodiments of the present application. Those skilled in the art may adjust them as needed to suit specific application scenarios.

[0023] The present application is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0024] See also Figure 1 and Figure 2 The present application discloses a method for controlling an automotive pump and valve thermal management system based on a variable structure algorithm. The automotive pump and valve thermal management system includes a variable structure controller, a motor, a PID controller, and a gear pump electrically connected in sequence. The output port of the gear pump is connected to the input port of a speed regulating valve. The variable structure controller is also electrically connected to the speed regulating valve. Coolant is transferred to the valve of the regulating valve through the gear pump for outflow. The method for controlling the automotive pump and valve thermal management system includes the following steps: Step S1: Control the starting motor to run at a low speed through the PID controller, and detect and determine whether the liquid flow at the valve of the speed regulating valve is within a first preset adjustment range: If yes, the motor is controlled by the PID controller to perform linear acceleration, and then the process returns to step S1; If not, the motor is controlled by the PID controller to maintain the current real-time speed and go to step S2; Step S2: detecting the real-time temperature of the motor and calculating the temperature difference between the real-time temperature and a preset target temperature, and controlling the valve opening of the speed regulating valve through the variable structure controller based on the temperature difference.

[0025] In the embodiment of the present application, step S2 includes: Step S21, detecting the real-time temperature of the motor and calculating the temperature difference between the real-time temperature and a preset target temperature; Step S22: determine whether the real-time temperature reaches the target temperature: If so, the variable structure controller controls the speed regulating valve to maintain the valve opening at the current moment; If not, go to step S23; Step S23: determine whether the temperature difference is within a second preset adjustment range: If yes, the variable structure controller controls the speed regulating valve to adjust the valve opening, and then returns to step S23; If not, go to step S24; Step S24, determine whether the target temperature is greater than the real-time temperature: If yes, the motor is controlled by the PID controller to perform linear acceleration, and then the process returns to step S21; If not, the motor is controlled by the PID controller to perform linear deceleration, and then the process returns to step S21.

[0026] In the embodiment of the present application, after controlling the speed regulating valve to maintain the valve opening at the current moment through the variable structure controller in step S22, the following steps are further included: Determine whether the temperature difference is within the third preset adjustment range: If so, exit; If not, go to step S24.

[0027] In the embodiment of the present application, after determining that the temperature difference is within the third preset adjustment range, the method further includes: Determine whether an external alarm signal or shutdown signal is received: If not, the variable structure controller controls the speed regulating valve to maintain the valve opening at the current moment; If so, the motor is turned off by the PID controller and the speed control valve is reset by the variable structure controller.

[0028] In the embodiment of the present application, for the three-phase asynchronous motor algorithm, the speed error Ev is obtained by feeding back the speed of the motor through the speed sensor. The asynchronous motor modeling is relatively common, and its torque can be expressed as , where K is the motor design parameter, φ is the magnetic flux, i is the rotor current, and cosφ is the rotor circuit operating factor. The rotor current i is often decoupled by coordinate transformation to obtain the current-speed model , where A and B are model parameter matrices, w(k+1) and w(k) are the speeds of the current sampling point and the next sampling point, respectively, and i(k) is the control current of the sampling point at this moment. In this embodiment, the linear extrapolation method is used Design a prediction function, where w(k-1) is the speed of the previous sampling point, and the exponential approach rate of the variable structure control algorithm , Design the approach function, where s is the sliding mode function, α and k p is the design parameter, combined with the error term A variable structure surface is established, where C is the error parameter matrix, W(k) and w(k) are the feedback speed and target speed, respectively.

[0029] In the embodiment of the present application, the above equations are combined to obtain the expression of the control current i(k): Among them, α and q0 are design parameters, and λ > 0, q0 > 0. Since the motor will produce complex nonlinear phenomena at low speed, the traditional PID control algorithm is not suitable for control. The variable structure control algorithm relies on it to always guide each state variable to the variable structure surface, thereby reflecting excellent low model dependence and robustness. It is suitable for nonlinear systems under low-speed operation of the motor. When the motor runs at higher power, its nonlinear characteristics are reduced. Considering the computational cost, the traditional PID control algorithm is used when the motor runs at high power: Among them, e w is the trajectory tracking error between the expected position and the measured position of the macro motion platform, t is the sampling time interval, k p 、k i and k d They are proportional gain, integral coefficient and differential coefficient respectively, and the flow velocity difference is directly feedback controlled through the flow velocity sensor.

[0030] In the embodiment of the present application, similarly, for a thin-walled pressure reducing valve, the liquid flow Q at the valve can be expressed as: in, Indicates the flow coefficient, QA is the flow rate, is the liquid density, and are the inlet pressure and outlet pressure respectively. The calculation of the flow rate is an existing technology and will not be described here. Since the valve control unit only exhibits linear characteristics under specific conditions, in order to utilize its faster response than the motor speed regulation, the above-mentioned pump control variable structure control algorithm can be used. Get its opening size x and get its power-opening equation through multiple experimental fitting. Indicates the effective cross-sectional area of ​​the valve port, and the flow difference e q Variable structure feedback control is performed as an input parameter to reduce its dependence on the model and achieve precision control; combined with the above-mentioned pump control coarse adjustment and valve control fine adjustment strategies, this application pre-sets the valve control speed regulation range, namely the first preset adjustment range, the second preset adjustment range and the third preset adjustment range. When the flow rate under pump control reaches the corresponding preset adjustment range, the valve control precision adjustment is enabled.

[0031] See also Figure 3 , the following is a description of the control logic for the control strategy process of the overall system: 1. The motor starts running at a constant low speed, and the speed control valve is at the initial limit position. Determine whether the flow rate reaches the first preset adjustment range; 2.1 If the motor has not reached the first preset adjustment range, the motor is linearly accelerated through PID controller feedback control, and a real-time determination is made again as to whether the motor has reached the first preset adjustment range; 2.1.1 If the speed has not reached the first preset adjustment range, the motor will continue to accelerate. If the speed has reached the first preset adjustment range, the motor will maintain its current speed. 2.2 If the first preset adjustment range is reached, the motor maintains the current speed; After the motor maintains its speed, the variable structure controller adjusts the valve opening size based on the feedback temperature difference, waits for the next temperature instruction, and determines whether the current real-time temperature meets the requirement: 3.1 If the real-time temperature does not meet the requirement, re-determine whether the temperature difference exceeds the second preset adjustment range: 3.1.1 If the second preset adjustment range is not exceeded, continue to return to adjust the variable structure controller to adjust the valve opening size; 3.1.2 If the second preset adjustment range has been exceeded, determine whether the target temperature is higher than the actual temperature: 3.1.2.1 If the target temperature is higher than the actual temperature, the motor will return to accelerated operation; 3.1.2.2 If the target temperature is lower than the actual temperature, the motor will return to deceleration operation; 3.2 If the real-time temperature has reached the required value (i.e., the circulation flow rate in the vehicle pump and valve thermal management system has reached the required value), the valve opening is maintained to determine whether the temperature difference exceeds the third preset adjustment range: 3.2.1 If the temperature difference exceeds the third preset adjustment range, return to determine whether the target temperature is higher than the real-time temperature: 3.2.2 If the temperature difference does not exceed the third preset adjustment range, it is determined whether an alarm signal and a shutdown signal are received.

[0032] 3.2.2.1 If not received, return to maintain valve opening; 3.2.2.2 If received, turn off the motor and reset the speed control valve.

[0033] In an embodiment of the present application, a pump-valve combination control scheme based on a variable structure algorithm is provided, wherein the pump control module uses an ARM controller to control the motor speed through RS485 communication, and the low-speed valve control module obtains the motor speed, pipeline flow and target temperature through a motor speed sensor, a flow sensor and a temperature sensor. A variable structure control strategy is used in the startup and low-speed stages to avoid the control instability of traditional control strategies in the face of high-order nonlinear models. In the high-speed operation stage, due to the high degree of linearity of its model, a PID controller is used to save computing costs. The above pump control scheme realizes coarse adjustment of the pipeline; a valve control temperature threshold is specified. When the temperature reaches the valve control fine adjustment range, the motor speed is maintained, the valve port flow and temperature data are fed back through the valve control flow sensor and the temperature sensor, and the data is fed back through the mainstream control chip and the AD digital-to-analog converter, and variable structure control is performed according to the flow difference, so that it has high precision and high robustness; through the above pump-valve combination control scheme, segmented thermal management of pump master coarse adjustment and valve slave fine adjustment is realized, thereby improving thermal management efficiency.

[0034] In the description of the present application, the description with reference to the terms "one embodiment", "some embodiments", "in the present embodiment", "specific example", or "some examples" means that the specific features, mechanisms, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, mechanisms, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples. In addition, those skilled in the art can combine and combine different embodiments or examples described in this specification and the features of different embodiments or examples, unless they are contradictory.

[0035] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.

Claims

1. A control method for an automobile pump valve thermal management system based on a variable structure algorithm, characterized in that: The automotive pump-valve thermal management system includes a variable structure controller, a motor, a PID controller, and a gear pump electrically connected in sequence. The output port of the gear pump is connected to the input port of the speed regulating valve. The variable structure controller is also electrically connected to the speed regulating valve. The gear pump transmits coolant to the valve of the regulating valve for outflow. The control method of the automotive pump-valve thermal management system includes the following steps: Step S1: Start the motor to run at a low speed by controlling the PID controller, and detect and determine whether the liquid flow at the valve of the speed regulating valve is within a first preset adjustment range: If yes, the motor is controlled by the PID controller to perform linear acceleration, and then the process returns to step S1; If not, the PID controller controls the motor to maintain the current real-time speed and goes to step S2; Step S2 , detecting the real-time temperature of the motor and calculating the temperature difference between the real-time temperature and a preset target temperature, and controlling and adjusting the valve opening of the speed regulating valve through the variable structure controller based on the temperature difference.

2. The automotive pump valve thermal management system control method according to claim 1, characterized in that: The step S2 comprises: Step S21, detecting the real-time temperature of the motor and calculating the temperature difference between the real-time temperature and the preset target temperature; Step S22: determine whether the real-time temperature reaches the target temperature: If yes, the variable structure controller controls the speed regulating valve to maintain the valve opening at the current moment; If not, go to step S23; Step S23: determine whether the temperature difference is within a second preset adjustment range: If so, the variable structure controller controls the speed regulating valve to adjust the valve opening, and then returns to step S23; If not, go to step S24; Step S24, determining whether the target temperature is greater than the real-time temperature: If yes, the motor is controlled by the PID controller to perform linear acceleration, and then the process returns to step S21; If not, the motor is controlled by the PID controller to perform linear deceleration, and then the process returns to step S21.

3. The automotive pump valve thermal management system control method according to claim 2, characterized in that: After the variable structure controller controls the speed regulating valve to maintain the valve opening at the current moment in step S22, the method further includes: Determine whether the temperature difference is within a third preset adjustment range: If so, exit; If not, go to step S24.

4. The automotive pump valve thermal management system control method according to claim 3, characterized in that: After determining that the temperature difference is within the third preset adjustment range, the method further includes: Determine whether an external alarm signal or shutdown signal is received: If not, the variable structure controller controls the speed regulating valve to maintain the valve opening at the current moment; If so, the motor is turned off by the PID controller and the speed regulating valve is reset by the variable structure controller.

5. The automotive pump valve thermal management system control method according to claim 1, characterized in that: In step S1, the inlet pressure and the outlet pressure of the speed regulating valve are detected, and the liquid flow rate is obtained according to the inlet pressure, the outlet pressure, the flow rate of the speed regulating valve, and the liquid density of the coolant.

6. The automotive pump valve thermal management system control method according to claim 5, characterized in that: In step S1, the liquid flow rate is obtained by the following calculation formula: in, represents the liquid flow rate; It represents the flow coefficient; represents the throughflow rate; represents the density of the liquid; represents the inlet pressure; Indicates the outlet pressure.

7. The automotive pump valve thermal management system control method according to claim 5, characterized in that: In the step S2, the valve opening is obtained according to the inlet pressure, the outlet pressure, the liquid density and the effective cross-sectional area of ​​the valve port of the speed regulating valve.

8. The automotive pump valve thermal management system control method according to claim 7, characterized in that: In step S2, the valve opening is obtained by the following calculation formula: in, Indicates the effective cross-sectional area of ​​the valve port; Indicates the valve opening; represents the density of the liquid; represents the inlet pressure; Indicates the outlet pressure.

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