A water pump control method and system

Abstract

This invention discloses a water pump control method and system, belonging to the field of equipment control technology. The method includes: constructing a reference model of the water pump; constructing an adjustable model of the water pump; calculating the cross-axis state equation based on the reference model and the adjustable model; estimating the rotor speed and rotation angle based on the cross-axis state equation and Popov's hyperstability theory; obtaining the initial rotor position of the water pump through pre-positioning technology; starting the water pump according to the initial rotor position and accelerating the water pump through an open-loop I / F acceleration method; after the water pump acceleration is completed, switching the system's open-loop speed and open-loop angle to the rotor speed and rotation angle estimated based on Popov's hyperstability theory. This invention can achieve continuous and smooth control, improving speed control accuracy and operational stability.

Description

Technical Field

[0001] This invention belongs to the field of control system technology, specifically relating to a water pump control method and system. Background Technology

[0002] With the popularization of new energy vehicles, thermal management technology for these vehicles has developed rapidly. Electronic water pumps are an indispensable and crucial component of thermal management in new energy vehicles. The performance of these pumps directly affects vehicle noise and energy consumption, thus impacting the passenger experience and driving range. Because the thermal management systems of new energy vehicles incorporate battery systems and heat pump technology compared to traditional gasoline vehicles, the power and efficiency requirements for electronic water pumps are significantly increased. Therefore, research on this electronic water pump drive technology is of great importance to the energy management of new energy vehicles.

[0003] Existing electronic water pump drive technology mainly uses DC brushless motors. Due to their significant improvements in structure, size, efficiency, and service life compared to earlier DC brushed motors, they are widely used in traditional fuel vehicles. However, with the increasing demands for noise, efficiency, power, and service life of electronic water pumps in the thermal management domain of new energy vehicles, the use of permanent magnet synchronous motors (PMSMs), which have higher magnetic density, lower ripple torque, and lower operating noise, meets the development needs of electronic water pumps for new energy vehicles.

[0004] For permanent magnet synchronous motors, the existing control strategy mainly adopts the six-step commutation method. This method divides one electrical cycle into six sectors, each 60°, with only two phases of the inverter bridge conducting in each sector. The rotor's sector position is typically obtained using Hall effect sensors or zero-crossing voltage detection. The motor is driven to rotate by designing the sequence of three-phase conduction. However, the six-step commutation method is a discrete control strategy, with only six switching states per electrical cycle, which limits the control accuracy. In situations with large speed variations or requiring high speed control accuracy, this discreteness can lead to low speed control precision and unstable operation. Summary of the Invention

[0005] To address the technical problems of low speed control accuracy and unstable operation of permanent magnet synchronous motors using the six-step commutation method in existing technologies, this invention provides a water pump control method and system.

[0006] First aspect

[0007] This invention provides a water pump control method, comprising:

[0008] S101: Construct a reference model for the water pump;

[0009] S102: Construct an adjustable model of the water pump;

[0010] S103: Calculate the cross-axis state equation based on the reference model and adjustable model of the water pump;

[0011] S104: Based on the aforementioned cross-axis state equation and the Popov superstability theory, estimate the rotor speed and rotation angle;

[0012] S105: Obtain the initial rotor position of the water pump through pre-positioning technology;

[0013] S106: Start the water pump according to the initial rotor position of the water pump, and accelerate the water pump through I / F open-loop acceleration;

[0014] S107: After the water pump has finished accelerating, the system's open-loop speed and open-loop angle are switched to the rotor speed and rotation angle estimated based on the Popov superstability theory.

[0015] Second aspect

[0016] The present invention provides a water pump control system for executing the water pump control method in the first aspect.

[0017] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0018] (1) In this invention, by constructing a reference model and an adjustable model of the water pump and calculating the cross-axis state equation, continuous and smooth control can be achieved instead of intermittent control, which can improve the speed control accuracy and running stability.

[0019] (2) In this invention, based on the Popov superstability theory, the rotor speed and rotation angle are estimated, and the control system can adjust the motor in real time according to the actual situation to better adapt to different loads and operating conditions, thereby improving the speed control accuracy and stability.

[0020] (3) In this invention, the initial rotor position of the water pump is obtained by pre-positioning technology, which can reduce the impact and vibration during startup and ensure that the water pump starts running from the correct position. Attached Figure Description

[0021] The preferred embodiments will now be described in a clear and easy-to-understand manner, in conjunction with the accompanying drawings, to further explain the above-mentioned characteristics, technical features, advantages, and implementation methods of the present invention.

[0022] Figure 1 This is a schematic flowchart of a water pump control method provided by the present invention. Detailed Implementation

[0023] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the specific implementation methods of the present invention will be described below with reference to the accompanying drawings. Obviously, the drawings described below are merely some embodiments of the present invention. For those skilled in the art, other drawings and other implementation methods can be obtained based on these drawings without any creative effort.

[0024] To keep the drawings concise, each figure only schematically shows the parts relevant to the invention, and these do not represent the actual structure of the product. Furthermore, to facilitate understanding, in some figures, only one of components with the same structure or function is schematically depicted, or only one is labeled. In this document, "one" not only means "only one," but can also mean "more than one."

[0025] It should also be further understood that the term "and / or" as used in this specification and the appended claims refers to any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0026] In this document, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections. They can refer to mechanical connections or electrical connections. They can refer to direct connections or indirect connections through an intermediate medium, or internal connections between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] Furthermore, in the description of this invention, the terms "first," "second," etc., are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0028] Example 1

[0029] In one embodiment, refer to the appendix to the specification. Figure 1 The diagram shows a flowchart of the water pump control method provided by the present invention.

[0030] The present invention provides a water pump control method, wherein the water pump uses a permanent magnet synchronous motor as a driver.

[0031] Among them, the permanent magnet synchronous motor (PMSM) is a type of high-efficiency, high-performance motor with high power density, good speed control performance, and high efficiency. The working principle of the PMSM is based on the interaction of electromagnetic induction and magnetic field. The rotor of the permanent magnet synchronous motor is equipped with constant permanent magnets, which do not require external energy to maintain during motor operation.

[0032] The water pump control method provided by this invention includes:

[0033] S101: Construct a reference model for the water pump.

[0034] Specifically, based on the mechanical characteristics of the pump and the principles of fluid flow, basic dynamic equations, such as mass conservation and energy conservation, can be established. The motor used in the pump is modeled, typically using an appropriate motor model, such as a permanent magnet synchronous motor (PMSM) model. The motor model describes the motor's electrical characteristics and torque output. Based on actual test data or parameters provided by the manufacturer, various parameters of the pump system are estimated, such as motor parameters, load parameters, and fluid flow parameters. The system's dynamic equations and the motor model are combined into a state-space model, which describes the pump system's behavior under different states. The state-space model can be represented in matrix form, containing the system's state variables, inputs, and outputs. Furthermore, based on the pump's application requirements, performance indicators such as speed range, steady-state error, and response time are determined.

[0035] In one possible implementation, a reference model of the water pump is constructed using the following formula:

[0036]

[0037] Among them, i q i represents the quadrature-axis component of the current. d R represents the direct-axis component of the current. s L represents the phase resistance. s Represents phase inductance, ω e ψ represents the rotor speed. f Indicates the magnetic flux linkage of the motor, u q This represents the quadrature-axis component of the voltage.

[0038] It should be noted that building a reference model for the water pump can help optimize the control algorithm and improve the pump's operating efficiency, performance, and stability.

[0039] S102: Construct an adjustable model of the water pump.

[0040] In one possible implementation, S102 specifically includes:

[0041] Using rotor speed as an estimation parameter, an adjustable model of the water pump is constructed using the following formula:

[0042]

[0043] in, i represents the estimated value of the quadrature-axis component of the current. d R represents the direct-axis component of the current. s L represents the phase resistance. s Indicates phase inductance, ψ represents the estimated value of the rotor speed. f Indicates the magnetic flux linkage of the motor, u q This represents the quadrature-axis component of the voltage.

[0044] It should be noted that constructing an adjustable model of the water pump enables real-time estimation of motor parameters, improving the adaptability, self-adaptability, and disturbance rejection of the control system, while reducing system cost and maintenance difficulty. The adjustable model of the water pump makes pump control more intelligent and efficient.

[0045] S103: Calculate the cross-axis state equation based on the reference model and adjustable model of the water pump.

[0046] The cross-axis state equation describes the dynamic behavior of the system in the AC coordinate system (dq coordinate system).

[0047] In one possible implementation, S1031: By subtracting the formula for the reference model of the water pump from the formula for the adjustable model, we obtain:

[0048]

[0049] S1032: Define state error Then the equation of state for the cross-axis can be obtained:

[0050]

[0051] in, This represents the first derivative of the state error e. y represents the system output, and C represents the observation coefficient matrix to be solved.

[0052] It should be noted that by differentiating the reference model and the adjustable model of the water pump, and then transforming the difference equation into the form of cross-axis state equations, the cross-axis state equations describing the dynamic behavior of the water pump in the AC coordinate system can be calculated.

[0053] S104: Based on the quadrature axis state equation and the Popov superstability theory, estimate the rotor speed and rotation angle.

[0054] The core idea of ​​Popov's hyperstability theory is to analyze the stability of a system by utilizing the relationship between phase and amplitude.

[0055] In one possible implementation, S104 specifically includes sub-steps S1041 to S1049:

[0056] S1041: Substituting the cross-axis state equation y=Ce into the Popov inequality, and letting C=I, where I represents the identity matrix, we get:

[0057]

[0058] Where η(0,t1) represents the integral term from time 0 to time t1. ω represents the estimated value of the rotor speed. e γ represents the rotor speed, e represents the state error, t represents time, and γ0 represents the control parameter.

[0059] S1042: The estimated rotor speed is expressed in proportional-integral form as follows:

[0060]

[0061] Where F1 represents the parameter matrix of the proportional-integral controller, y represents the system output, t represents time, τ represents the integral variable, and F2 represents the parameter matrix for the first correction. The initial value represents the estimated value of the rotor speed.

[0062] S1043: Substituting the rotor speed, expressed in the form of a proportional integral, into the Popov inequality, we get:

[0063]

[0064] S1044: If the above Popov inequality holds, then the following two inequalities also hold:

[0065]

[0066]

[0067] Where η1(0,t1) represents the first integral term, γ1 represents the first control parameter, η2(0,t1) represents the second integral term, and γ2 represents the second control parameter.

[0068] S1045: Construct a function f(t) such that the function f(t) satisfies:

[0069]

[0070]

[0071] S1046: Yes Differentiate both sides and substitute. We can obtain:

[0072] F1(y,t,τ)=k i Me(k i >0)

[0073] Where, k i This represents the first coefficient.

[0074] S1047: Let F2(y,t) = k p Me(k p If the expression is greater than or equal to 0, then the Popov inequality can be expressed as:

[0075]

[0076] Where, k p represents the second coefficient, and s represents the phase.

[0077] S1048: Substitution as well as We can obtain:

[0078]

[0079] S1049: Integrating the above equation yields an estimated value for the rotation angle:

[0080]

[0081] in, This represents an estimated value of the rotation angle. This represents the estimated value of the rotor speed, and τ represents the integral variable.

[0082] It should be noted that the control strategy based on Popov's superstability theory provides specific calculation methods and steps, enabling the system to more effectively estimate and control the rotor speed and rotation angle, thereby improving the system's operational stability and performance accuracy.

[0083] S105: Obtain the initial rotor position of the water pump through pre-positioning technology.

[0084] In one possible implementation, S105 specifically includes:

[0085] The initial rotor position of the water pump can be obtained using the following formula:

[0086]

[0087] Where I represents the rated current, T np represents the rated torque of the motor. n Indicates rated power, ψ f θ represents the motor flux linkage, and θ represents the initial rotor angle.

[0088] It should be noted that during motor startup, especially for high-performance permanent magnet synchronous motors, sudden current input can cause shocks and vibrations, affecting system stability. Pre-positioning technology, by obtaining the initial rotor position, allows the motor to accelerate from a more stable starting position, reducing startup shocks and vibrations, thus helping to protect the equipment and extend its lifespan.

[0089] S106: Start the water pump according to the initial rotor position of the water pump, and accelerate the water pump through I / F open-loop acceleration.

[0090] Among them, I / F open-loop acceleration (Iterative Feedback Tuning with Feedforward Open-Loop Acceleration) is a control strategy typically used to accelerate the movement of a system or device. In this invention, it is used to start and accelerate a water pump to gradually bring it to a predetermined operating state.

[0091] In one possible implementation, S106 specifically includes:

[0092] The water pump is accelerated by using an I / F open-loop acceleration method to obtain the open-loop velocity and open-loop angle.

[0093] The open-loop velocity accelerated by I / F can be expressed as:

[0094]

[0095] Where, ω i Let ω represent the open-loop velocity, a represent the open-loop acceleration, t represent time, and ω represent the open-loop velocity. tag Indicates the target rotational speed.

[0096] Wherein, the open-loop acceleration a satisfies:

[0097] a≤p n (T e -T n ) / J

[0098] Where, p n T represents the rated power. e T represents the current torque output of the motor. n J represents the rated torque of the motor, and J represents the moment of inertia.

[0099] The open-loop angle of I / F open-loop acceleration can be expressed as:

[0100] θ i =∫ω i dt

[0101] Where, θ i This indicates the open-loop angle.

[0102] It should be noted that the I / F open-loop acceleration control strategy can reduce the shock and mechanical vibration during startup by gradually increasing acceleration, thereby alleviating the mechanical stress on the system and equipment and helping to extend their lifespan. Furthermore, the I / F open-loop acceleration method can be adjusted according to actual load and environmental conditions to achieve better adaptive control. This means that the system can automatically adjust the acceleration strategy according to changing conditions, thereby improving system performance and stability.

[0103] S107: After the water pump has finished accelerating, the system's open-loop speed and open-loop angle are switched to the rotor speed and rotation angle estimated based on the Popov superstability theory.

[0104] It should be noted that switching the system's open-loop speed and open-loop angle to rotor speed and rotation angle estimated based on Popov's superstability theory can improve the system's control accuracy, stability, real-time performance, and adaptability, while reducing system cost and sensor dependence, thereby enhancing the performance and reliability of the pump control system.

[0105] In one possible implementation, S107 specifically includes:

[0106] The open-loop velocity and open-loop angle of the system are switched to the rotor velocity and rotation angle estimated based on the Popov superstability theory through a smooth transition algorithm.

[0107] It should be noted that the smooth transition algorithm enables a gradual transition during the switching process, avoiding sudden changes and shocks. This reduces startup shock and mechanical vibration in the pump system, helping to extend equipment life. Furthermore, the smooth transition algorithm ensures stable system operation during switching, avoiding sudden changes in control input, thereby improving the control smoothness and operational stability of the pump system.

[0108] In one possible implementation, S107 specifically includes S1071 and S1072:

[0109] S1071: Constructing a smooth transition function based on the cosine function:

[0110]

[0111] Where C(·) represents the smooth transition function and t represents time.

[0112] S1072: The open-loop velocity and open-loop angle of the system are switched to rotor velocity and rotation angle estimated based on Popov's hyperstability theory using the following formula:

[0113]

[0114] Where, θ n θ represents the rotation angle of the system. i Indicates the open-loop angle. ω represents the estimated value of the rotation angle based on Popov's hyperstability theory. i This indicates the current rotor speed, M1 represents the low threshold, and M2 represents the high threshold.

[0115] It should be noted that by constructing a smooth transition function and switching the system's open-loop velocity and open-loop angle to estimated values ​​based on Popov's hyperstability theory, the system's stability, control accuracy, and user experience can be improved. At the same time, mechanical stress, energy consumption fluctuations, and system oscillations can be reduced, thereby improving the performance and reliability of the pump system.

[0116] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0117] (1) In this invention, by constructing a reference model and an adjustable model of the water pump and calculating the cross-axis state equation, continuous and smooth control can be achieved instead of intermittent control, which can improve the speed control accuracy and running stability.

[0118] (2) In this invention, based on the Popov superstability theory, the rotor speed and rotation angle are estimated, and the control system can adjust the motor in real time according to the actual situation to better adapt to different loads and operating conditions, thereby improving the speed control accuracy and stability.

[0119] (3) In this invention, the initial rotor position of the water pump is obtained by pre-positioning technology, which can reduce the impact and vibration during startup and ensure that the water pump starts running from the correct position.

[0120] Example 2

[0121] In one embodiment, the present invention provides a water pump control system for executing the water pump control method in Embodiment 1.

[0122] The water pump control system provided by the present invention can realize the steps and effects of the water pump control method in the above embodiment 1. To avoid repetition, the present invention will not repeat them.

[0123] Compared with the prior art, the present invention has at least the following beneficial technical effects:

[0124] (1) In this invention, by constructing a reference model and an adjustable model of the water pump and calculating the cross-axis state equation, continuous and smooth control can be achieved instead of intermittent control, which can improve the speed control accuracy and running stability.

[0125] (2) In this invention, based on the Popov superstability theory, the rotor speed and rotation angle are estimated, and the control system can adjust the motor in real time according to the actual situation to better adapt to different loads and operating conditions, thereby improving the speed control accuracy and stability.

[0126] (3) In this invention, the initial rotor position of the water pump is obtained by pre-positioning technology, which can reduce the impact and vibration during startup and ensure that the water pump starts running from the correct position.

[0127] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0128] The above embodiments merely illustrate several implementation methods of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention patent should be determined by the appended claims.

Claims

1. A water pump control method, characterized in that, The water pump uses a permanent magnet synchronous motor as its driver, and the control method includes: S101: Construct a reference model for the water pump; S102: Construct an adjustable model of the water pump; S103: Calculate the cross-axis state equation based on the reference model and adjustable model of the water pump; S104: Based on the aforementioned cross-axis state equation and the Popov superstability theory, estimate the rotor speed and rotation angle; S105: Obtain the initial rotor position of the water pump through pre-positioning technology; S106: Start the water pump according to the initial rotor position of the water pump, and accelerate the water pump through I / F open-loop acceleration; S107: After the water pump has finished accelerating, the open-loop speed and open-loop angle of the system are switched to the rotor speed and rotation angle estimated based on the Popov superstability theory. Specifically, S101 is as follows: The reference model of the water pump is constructed using the following formula: ; in, Represents the quadrature-axis component of the current. Represents the direct-axis component of the current. Indicates phase resistance. Indicates phase inductance, Indicates the rotor speed. Indicates the magnetic flux linkage of the motor. Represents the quadrature-axis component of voltage; Specifically, S102 is as follows: Using rotor speed as an estimation parameter, an adjustable model of the water pump is constructed using the following formula: ; in, This represents the estimated value of the quadrature-axis component of the current. Represents the direct-axis component of the current. Indicates phase resistance. Indicates phase inductance, This represents an estimated value of the rotor speed. Indicates the magnetic flux linkage of the motor. Represents the quadrature-axis component of voltage; Specifically, S103 includes: S1031: By subtracting the formula for the reference model of the water pump from the formula for the adjustable model, we obtain: ; S1032: Define state error Then we can obtain the equation of state for the cross-axis: ; in, Indicates state error The first derivative, , y Indicates system output, C This represents the observation coefficient matrix to be solved.

2. The water pump control method according to claim 1, characterized in that, S104 specifically includes: S1041: Cross-axis state equations Substitute into the Popov inequality and let C = I , I Representing the identity matrix, we can obtain: ; in, Indicates from time 0 to time t The integral term of 1, This represents an estimated value of the rotor speed. ω e Indicates the rotor speed. e Indicates state error, t Indicates time, Indicates control parameters; S1042: The estimated rotor speed is expressed in proportional-integral form as follows: ; in, F 1 represents the parameter matrix of the proportional-integral controller. y Indicates system output, t Indicates time, τ Represents the integral variable. F 2 represents the parameter matrix for one correction. The initial value representing the estimated rotor speed; S1043: Substituting the rotor speed, expressed in the form of a proportional integral, into the Popov inequality, we get: ; S1044: If the above Popov inequality holds, then the following two inequalities also hold: ; in, Indicates the first integral term. Indicates the first control parameter. Indicates the second integral term. Indicates the second control parameter; S1045: Construct a function f ( t ), making the function f ( t )satisfy: ; S1046: Yes Differentiate both sides and substitute. We can obtain: ; in, k i Indicates the first coefficient; S1047: Order Then the Popov inequality can be expressed as: ; in, k p Indicates the second coefficient. s Indicates phase; S1048: Substitution We can obtain: ; S1049: Integrating the above equation yields an estimated value for the rotation angle: ; in, This represents an estimated value of the rotation angle. This represents an estimated value of the rotor speed. This represents the integral variable.

3. The water pump control method according to claim 2, characterized in that, Specifically, S105 is: The initial rotor position of the water pump can be obtained using the following formula: ; in, I Indicates the rated current. T n This indicates the rated torque of the motor. p n Indicates the rated power. Indicates the magnetic flux linkage of the motor. θ This indicates the initial rotor angle.

4. The water pump control method according to claim 3, characterized in that, Specifically, S106 is: The water pump is accelerated by I / F open-loop acceleration to obtain the open-loop velocity and open-loop angle; The open-loop velocity accelerated by I / F open-loop acceleration can be expressed as: ; in, ω i Indicates the open-loop velocity. a Indicates open-loop acceleration. t Indicates time, ω tag Indicates the target rotational speed; Among them, open-loop acceleration a satisfy: ; in, p n Indicates the rated power. T e This indicates the current torque output of the motor. T n This indicates the rated torque of the motor. J Indicates the moment of inertia; The open-loop angle of I / F open-loop acceleration can be expressed as: ; in, θ i This indicates the open-loop angle.

5. The water pump control method according to claim 1, characterized in that, Specifically, S107 is: The open-loop velocity and open-loop angle of the system are switched to the rotor velocity and rotation angle estimated based on the Popov superstability theory through a smooth transition algorithm.

6. The water pump control method according to claim 5, characterized in that, Specifically, S107 includes: S1071: Constructing a smooth transition function based on the cosine function: ; in, This represents a smooth transition function. t Indicates time; S1072: The open-loop velocity and open-loop angle of the system are switched to rotor velocity and rotation angle estimated based on Popov's hyperstability theory using the following formula: ; in, θ n Indicates the rotation angle of the system. θ i Indicates the open-loop angle. This represents the estimated value of the rotation angle based on Popov's hyperstability theory. ω i Indicates the current rotor speed. M 1 indicates a low threshold. M 2 indicates a high threshold.

7. A water pump control system, characterized in that, Used to perform the water pump control method according to any one of claims 1 to 6.

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