Permanent magnet synchronous motor sliding mode control method
By adopting a combination of new segmented approach law and adaptive speed regulator in permanent magnet synchronous motors, the problems of traditional control methods in dynamic response and vibration are solved, and faster approach speed and lower Vibrate to ensure that the motor starts normally at low speed.
Patent Information
- Application Number
- CN202411317646.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-20
- Publication Date
- 2024-12-31
AI Technical Summary
Traditional PID control is difficult to meet the needs of multivariable, nonlinear, and strongly coupled systems of permanent magnet synchronous motors. The existing sliding mode control method has room for improvement in dynamic response and jitter.
Using a new segmented approach law and adaptive speed regulator, the motor control algorithm is optimized through the combination of sliding mode control model and adaptive speed regulator, to improve the approach speed and reduce jitter, ensuring that the motor is normal at low speed state. start up.
It achieves faster approach speed and lower vibration, ensuring that the motor starts normally at low speed, and improving the response speed and stability of the control system.
Smart Images
Figure CN119231988A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of motor control, and in particular to a sliding mode control method for a permanent magnet synchronous motor. Background Art
[0002] Permanent magnet synchronous motor has the advantages of low temperature rise, low loss, high efficiency, short start-up time, etc., and is widely used in daily production and industrial life. Since the permanent magnet synchronous motor is a multivariable, nonlinear, and strongly coupled system, the traditional PID control requires an accurate mathematical model and is difficult to meet the needs of the permanent magnet synchronous motor control system.
[0003] Sliding mode control is essentially a discontinuous nonlinear control. It has become a hot topic in the research of permanent magnet synchronous motor control because of its advantages such as fast response and simple implementation. China's invention patent "A fast integral terminal sliding mode control of permanent magnet synchronous motor" CN115967315A proposes a fast integral terminal sliding mode control method based on a new reaching law, which improves the problems of slow dynamic response and large jitter in the control system; China's invention patent "Sliding mode control method of permanent magnet synchronous linear motor based on reaching law and disturbance compensation" CN116317756A proposes a sliding mode control method of permanent magnet synchronous linear motor based on reaching law and disturbance compensation, which can make the motor have good static and dynamic performance; China's invention patent "Sliding mode control method of permanent magnet synchronous motor based on adaptive reaching law" CN115441783A proposes a sliding mode control method of adaptive reaching law, which can converge to the sliding surface faster than the traditional exponential reaching law, and can effectively reduce system jitter. The Chinese invention patent "Non-singular terminal sliding mode control method of permanent magnet synchronous motor based on new reaching law" CN115528961A proposes a non-singular terminal sliding mode control based on a new reaching law, which is characterized by greatly improving the reaching speed. The Chinese invention patent "A composite control method for permanent magnet synchronous motor" CN116094384A proposes a composite sliding mode control method, which has obvious improvements in overshoot, response speed and robustness. Summary of the invention
[0004] In order to improve the approach speed of the motor control algorithm and reduce the chattering of the control system based on the existing technology, the present application provides a sliding mode control method for a permanent magnet synchronous motor.
[0005] The technical solution of the present invention provides a permanent magnet synchronous motor sliding mode control method, comprising the following steps.
[0006] S1. Build a sliding mode control system for a permanent magnet synchronous motor: The sliding mode control function of the sliding mode control model of the system is defined as:
[0007] in, , , , , , are all coefficients of the model and satisfy , , , , , are odd numbers and ; is the sliding surface, is the first state quantity, is the second state quantity.
[0008] The sliding mode control reaching law of the sliding mode control model of the system is defined as:
[0009]
[0010] in, , , are model coefficients.
[0011] S2. Control the motor based on the permanent magnet synchronous motor sliding mode control module. The specific control process is as follows: S21, sampling the rotor position signal to determine the motor rotor angle With angular velocity ; S22, update the state quantity of the permanent magnet synchronous motor sliding mode control system based on the motor rotor angular velocity obtained in S21 Update the state of the system; S23, updating the q-axis current, and applying the sliding mode control algorithm to the sliding mode control model of the system based on the state quantity updated in S22 to obtain the q-axis current of the system.
[0012] Preferably, the permanent magnet synchronous motor sliding mode control system further comprises an adaptive speed regulator, which is used to adjust the reference speed of the sliding mode control model. The adaptive speed regulator adjusts the reference speed when the permanent magnet synchronous motor starts with a speed of zero. The increment is not zero.
[0013] Preferably, the adaptive speed regulator updates the reference angular velocity of the system according to the following formula:
[0014] in, is a timing mark, is the reference angular velocity updated in the next control cycle, is the current reference angular velocity, and , is the actual angular velocity of the permanent magnet synchronous motor collected, is the preset increment factor.
[0015] Preferably, based on the motor rotor angular velocity obtained in S21 The process of updating the state quantity of the system is updated as follows:
[0016] in, is the given value of angular velocity in the algorithm, is the measured motor angular velocity.
[0017] Preferably, the motion equation and torque equation of the permanent magnet synchronous motor are:
[0018] in, is the electromagnetic torque, is the load torque, is the number of pole pairs of the permanent magnet synchronous motor, is the moment of inertia of the motor, is the permanent magnetic flux linkage, is the q-axis current, is the torque constant of the permanent magnet synchronous motor.
[0019] Preferably, the q axial flow is calculated by the following formula:
[0020] in, ,
[0021] The permanent magnet synchronous motor sliding mode control method of the present application provides a new type of segmented approach law, which can accelerate the system approach speed while reducing system jitter. In addition, an adaptive speed regulator is designed. When the DC bus voltage is constant and the given speed is lower than the minimum starting speed of the motor, the starting speed of the motor can be adaptively adjusted, thereby avoiding the problem that the motor cannot be started normally due to the low speed setting when the DC bus voltage is constant, causing damage to the motor. BRIEF DESCRIPTION OF THE DRAWINGS
[0022] Figure 1 A control block diagram of a control system of a permanent magnet synchronous motor corresponding to the sliding mode control method of the permanent magnet synchronous motor of the present invention; Figure 2It is a flow chart of applying an adaptive speed regulator to the sliding mode control method of a permanent magnet synchronous motor of the present invention;.
[0023] Figure 3 It is a comparison diagram of the phase trajectory between the improved reaching law of the present application and the traditional exponential reaching law; Figure 4 yes Figure 3 A partial enlarged schematic diagram of Figure 5-7 It is a schematic diagram comparing the improved permanent magnet synchronous motor sliding mode control method of the present application with the traditional sliding mode control algorithm under low speed conditions. DETAILED DESCRIPTION
[0024] The following is a detailed description of this patent type in conjunction with the accompanying drawings and specific embodiments. In this specification, the dimensions of the drawings do not represent the actual size ratios. The drawings are only used to reflect the relative position relationship and connection relationship between the components. Components with the same name or the same number represent similar or identical structures and are only for illustrative purposes.
[0025] Figure 1 The control block diagram of the control system of the permanent magnet synchronous motor corresponding to the sliding mode control method of the permanent magnet synchronous motor of the present application is shown in FIG. The control system includes a speed loop improved fast non-singular terminal sliding mode control module, a coordinate transformation module, an SVPWM module, a rectifier bridge module, a motor module, and an adaptive speed regulation module.
[0026] The sliding surface of the permanent magnet synchronous motor sliding mode control module is defined as , its first state quantity is recorded as , and its second state quantity is recorded as The sliding mode control module of permanent magnet synchronous motor is based on the fast non-singular terminal sliding mode function. Its expression is:
[0027] in, , , , , , are all coefficients of the model and satisfy , , , , , are odd numbers and .
[0028] By taking the derivative of the sliding mode function, the expression of the derivative of the fast non-singular terminal sliding mode function can be obtained as:
[0029] The relationship between the state variables and the motor operating state is defined by the following equation:
[0030] in, is the given value of angular velocity in the algorithm, The motor rotor position signal obtained by the sampling process is updated to measure the motor angular velocity.
[0031] The motion equation and torque equation of the permanent magnet synchronous motor are given by:
[0032] in, is the electromagnetic torque, is the load torque, is the number of pole pairs of the permanent magnet synchronous motor, is the moment of inertia of the motor, is the permanent magnetic flux linkage, is the q-axis current, is the torque constant of the permanent magnet synchronous motor.
[0033] A new reaching law based on fast non-singular terminal sliding mode control is defined as follows.
[0034]
[0035]
[0036] in, , , are model coefficients. Note that in the above reaching law, The cutoff point of the first state variable It is divided into two different approaching intervals by the boundary. Obviously, it can be observed that the system has different approaching speeds in different approaching intervals. When the system reaches the sliding surface, the improved approaching law can make the system converge quickly and reduce the steady-state chattering of the system.
[0037] In summary, the speed loop sliding mode control outputs a given current for:
[0038] in, ,
[0039] Usually, the reference angular velocity of sliding mode control is It is responsive to the angular velocity regulation of the permanent magnet synchronous motor, but at low speed, especially when the motor is stopped, the update of the reference angular velocity may stop or lag. The reason is that the angular velocity at this time is zero, and it is impossible to form effective feedback for the reference angular velocity. In order to solve this problem and ensure that the motor can start normally and quickly enter a steady state when it is started at no speed, this application optimizes the speed regulation, and adds an adaptive regulator in the speed regulation process, and its working expression is:
[0040] in, is a timing mark, is the reference angular velocity updated in the next control cycle, is the current reference angular velocity, and , is the actual angular velocity of the permanent magnet synchronous motor collected, is the preset increment factor.
[0041] like Figure 2 As shown in the figure, the adaptive regulator can automatically increase the speed until the motor starts normally when the DC bus voltage is constant and the set initial starting speed cannot start the motor normally. When the motor runs normally, the adaptive speed regulator outputs the actual speed value of the motor. When the initial starting speed can meet the motor starting requirements, the adaptive speed regulator outputs the given speed value of the motor.
[0042] After the motor starts, regardless of whether the motor rotates in the forward or reverse direction and whether the speed meets the standard, the above formula contains The term will be eliminated, so the reference speed remains unchanged and the adaptive regulator does not work. When the motor is not started, the actual angular velocity is zero, including The term is not zero, so the reference angular velocity will increase to meet the starting requirements. Therefore, the adaptive regulator is mainly used to adjust the control process when the motor is not started. Make corrections to ensure the normal and stable starting of the motor.
[0043] The permanent magnet synchronous motor sliding mode control method of the present application includes the following steps.
[0044] S1. Build a sliding mode control system for a permanent magnet synchronous motor. The sliding mode control function of the sliding mode control model of the system is defined as:
[0045] in, , , , , , are all coefficients of the model and satisfy , , , , , are odd numbers and ; is the sliding surface, is the first state quantity, is the second state quantity, satisfying:
[0046] in, is the given value of angular velocity in the algorithm, is the measured motor angular velocity, The sliding mode control reaching law of the sliding mode control model of the system is defined as:
[0047]
[0048] in, , , are model coefficients.
[0049] Preferably, the system further has an adaptive speed regulator, which updates the reference angular velocity of the system according to the following formula:
[0050] in, is a timing mark, is the reference angular velocity updated in the next control cycle, is the current reference angular velocity, and , is the actual angular velocity of the permanent magnet synchronous motor collected, is the preset increment factor.
[0051] S2. Control the motor based on the permanent magnet synchronous motor sliding mode control module. The specific control process is as follows: S21, sampling the rotor position signal to determine the motor rotor angle With angular velocity
[0052] S22, update the state quantity of the permanent magnet synchronous motor sliding mode control system based on the motor rotor angular velocity obtained in S21 Update the state of the system.
[0053] S23, updating the q-axis current, and applying the sliding mode control algorithm to the sliding mode control model of the system based on the state quantity updated in S22 to obtain the q-axis current of the system.
[0054] Figure 3 is a comparison diagram of the phase trajectory of the improved reaching law of the present application and the traditional exponential reaching law, where 1 is the traditional exponential reaching law, 2 is the improved reaching law, and 3 is the sliding surface. Figure 2 The 4th one is magnified and obtained Figure 4 ; 5 is the traditional exponential convergence law, and 6 is the improved convergence law of the present invention. Figure 2 It can be determined that since the present application provides a piecewise convergence law, a significantly faster initial convergence trend to the sliding surface is achieved compared to the traditional exponential convergence law, and the sliding surface can converge to the sliding surface and stabilize earlier than the traditional sliding surface. Figure 4 The local enlarged diagram shows that the convergence process of the sliding mode function of the present application is smoother and has significantly lower jitter than the prior art.
[0055] Figure 5-7 The fast non-singular terminal sliding mode control algorithm improved by the present application is compared with the traditional sliding mode control algorithm under low speed conditions, where 7 is the traditional sliding mode control algorithm and 8 is the fast non-singular terminal sliding mode control algorithm improved by the present invention. For the convenience of observation, Figure 4 9 and 10 in the figure are enlarged to obtain Figure 6 as well as Figure 7 . Among them, 11 and 13 are traditional sliding mode control algorithms, and 12 and 14 are fast non-singular terminal sliding mode control algorithms improved by the present invention. Figure 5 and Figure 6 It can be seen that the fast non-singular terminal sliding mode control improved by the present invention not only accelerates the response speed and shortens the response time, but also effectively suppresses the chattering.
[0056] The above content only describes the preferred implementation methods of this patent type and does not limit the scope of this patent type. Without departing from the design spirit of this patent type, various modifications and improvements made to the technical solutions of this patent type by ordinary technicians in this field should fall within the protection scope determined by the claims of this patent type.
Claims
1. A sliding mode control method for a permanent magnet synchronous motor, characterized in that: The steps include: S1. Build a sliding mode control system for a permanent magnet synchronous motor: The sliding mode control function of the sliding mode control model of the system is defined as: in, , , , , , are all coefficients of the model and satisfy , , , , , are odd numbers and ; is the sliding surface, is the first state quantity, is the second state quantity; The sliding mode control reaching law of the sliding mode control model of the system is defined as: in, , , All are model coefficients; S2. Control the motor based on the permanent magnet synchronous motor sliding mode control module. The specific control process is as follows: S21, sampling the rotor position signal to determine the motor rotor angle With angular velocity ; S22, update the state quantity of the permanent magnet synchronous motor sliding mode control system based on the motor rotor angular velocity obtained in S21 Update the state of the system; S23, updating the q-axis current, and applying the sliding mode control algorithm to the sliding mode control model of the system based on the state quantity updated in S22 to obtain the q-axis current of the system.
2. The sliding mode control method of a permanent magnet synchronous motor according to claim 1, characterized in that: The permanent magnet synchronous motor sliding mode control system also includes an adaptive speed regulator, which is used to adjust the reference speed of the sliding mode control model. The adaptive speed regulator adjusts the reference speed when the permanent magnet synchronous motor starts with a speed of zero. The increment is not zero.
3. The sliding mode control method of a permanent magnet synchronous motor according to claim 2, characterized in that: The adaptive speed regulator updates the reference angular velocity of the system as follows: in, is a timing mark, is the reference angular velocity updated in the next control cycle, is the current reference angular velocity, and , is the actual angular velocity of the permanent magnet synchronous motor acquired, is the preset increment factor.
4. The sliding mode control method of a permanent magnet synchronous motor according to claim 1, characterized in that: Based on the motor rotor angular velocity obtained in S21 The process of updating the state quantity of the system is updated as follows: in, is the given value of angular velocity in the algorithm, is the measured motor angular velocity.
5. The sliding mode control method for a permanent magnet synchronous motor according to any one of claims 1, 2 and 4, characterized in that: The motion equation and torque equation of the permanent magnet synchronous motor are: in, is the electromagnetic torque, is the load torque, is the number of pole pairs of the permanent magnet synchronous motor, is the moment of inertia of the motor, is the permanent magnetic flux linkage, is the q-axis current, is the torque constant of the permanent magnet synchronous motor.
6. The sliding mode control method of a permanent magnet synchronous motor according to claim 5, characterized in that: The q axial flow is calculated by the following formula: in, , .