Electric vehicle permanent magnet synchronous motor control algorithm and system

Abstract

The invention discloses an electric vehicle permanent magnet synchronous motor control algorithm and system, and the algorithm comprises a control algorithm which comprises a sliding-mode observer algorithm, current calculation, voltage calculation, rotor electrical angle calculation and three-phase proportion calculation. The position information of the rotor is estimated by adopting a sliding mode variable structure method, the dependence on a traditional mechanical sensor is reduced, a sliding mode observer effectively filters noise in the observation process, high robustness is achieved, stable operation of the system in a complex environment is guaranteed, a sliding mode control algorithm is combined with vector control, and the system reliability is improved. By dynamically adjusting the control parameters, the system quickly responds to external interference, rotating speed fluctuation is reduced, the steady-state and dynamic performance of the motor is improved, the stability of the system is kept through an improved vector control algorithm, meanwhile, the dynamic response performance is remarkably improved, and overshoot and oscillation are reduced.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of permanent magnet synchronous motors, in particular to a control algorithm and system for a permanent magnet synchronous motor of an electric vehicle. BACKGROUND

[0002] The permanent magnet synchronous motor of an electric vehicle is very efficient during operation, can accurately control torque and speed, is more energy-saving than a traditional induction motor, can provide high torque in a wide speed range, which means that a large amount of power can be generated during acceleration while maintaining stable performance, due to its structural design, the permanent magnet synchronous motor produces relatively low noise during operation, so that the electric vehicle is more quiet during driving, the structure of the permanent magnet synchronous motor is relatively simple and has fewer components, so less maintenance is required, the permanent magnet synchronous motor has a long service life and a low failure rate, which makes them more reliable in the application of electric vehicles, compared with other types of motors, the control of the permanent magnet synchronous motor is easier to implement and adjust, the rotor and stator of the permanent magnet synchronous motor are made of lightweight materials, which makes the entire motor lighter in weight, which is beneficial to improve the cruising range of the vehicle, and the motor still maintains high efficiency during high-speed operation, and the speed range and flux-weakening performance of the motor can be improved by reasonably designing the permanent magnet magnetic circuit structure.

[0003] The permanent magnet synchronous motor is composed of a stator and a rotor, the stator adopts a lamination structure to reduce the iron loss during operation of the motor, the rotor can be made of solid or laminated, and pre-magnetized permanent magnets are installed on the rotor, which can generate a strong magnetic field during rotation to provide greater output torque, the permanent magnet synchronous motor uses permanent magnet material as the rotor magnetic field source, without the need for an external excitation device, thus reducing excitation loss and improving the efficiency of the motor, according to different working conditions and designs, the efficiency of the permanent magnet synchronous motor can reach more than 90%, which is much higher than the efficiency of an asynchronous motor, and it is also the most common type of motor on electric vehicles, and almost more than 90% of pure electric vehicles use permanent magnet synchronous motors as power motors.

[0004] The working principle of the permanent magnet synchronous motor is based on the interaction between the magnetic field generated by the permanent magnets of the synchronous rotor and the electromagnetic field of the stator winding to realize rotary driving, the rotor of the permanent magnet synchronous motor is usually made of rare earth materials, which makes it have a very high magnetic energy product, so it has obvious advantages in weight and volume compared with traditional asynchronous motors, in addition, the torque and speed control accuracy of the permanent magnet synchronous motor is high, which can better meet the demand of new energy vehicles for motor dynamic response performance, however, although the permanent magnet synchronous motor has obvious advantages in structure and efficiency, the complexity of the control algorithm is also increased accordingly.

[0005] However, the traditional permanent magnet synchronous motor has the following disadvantages: Traditional permanent magnet synchronous motor control methods, such as vector control and direct torque control, can achieve good steady-state performance, but in the dynamic process, they often face problems such as large overshoot, chattering and the like, which affect the overall performance of the system. SUMMARY

[0006] The purpose of the present application is to provide an electric vehicle permanent magnet synchronous motor control algorithm and system to solve the problem of the traditional permanent magnet synchronous motor control method, such as vector control and direct torque control, which can achieve good steady-state performance, but in the dynamic process, they often face problems such as large overshoot, chattering and the like, which affect the overall performance of the system.

[0007] To achieve the above purpose, the present application provides the following technical solution: an electric vehicle permanent magnet synchronous motor control algorithm, comprising a control algorithm, the control algorithm comprising a sliding mode observer algorithm, current calculation, voltage calculation, rotor electric angle calculation and three-phase proportion calculation.

[0008] As a preferred technical solution of the present application, the sliding mode observer algorithm is provided with back electromotive force Ealpha and Ebeta to obtain the inverse tangent, which converts the dq coordinate system in vector control to the alpha-beta two-phase stationary coordinate system, and the voltage equation of the two-phase stationary coordinate system is as follows: , Wherein the expression of back electromotive force is as follows: , The motor current model contains a constant differential equation calculation as follows: , The current equation calculation formula in the voltage model is as follows: , According to the motor model, the sliding mode observer model is established with the same order and corresponding format, and the calculation formula is as follows: , Wherein the expression of back electromotive force is as follows: , The error equation expression is as follows: .

[0009] As a preferred technical solution of the present application, the current calculation is the stator phase current, and the calculation formula is as follows: , Wherein i d is the direct axis current output value, i q is the alternating current output value, and I sThe stator phase current.

[0010] As a preferred technical solution of the present application, the voltage calculation is specifically a quadrature axis voltage expectation value, and the calculation formula is as follows: , σ is a load angle, is a direct axis voltage expectation value, is a quadrature axis voltage expectation value.

[0011] As a preferred technical solution of the present application, the rotor electric angle calculation is specifically: , Wherein f is a power supply frequency, and p is a pole pair number of the motor.

[0012] As a preferred technical solution of the present application, the three-phase proportion calculation formula is as follows: , Wherein Ia is a phase current, p is a pole pair number of the motor, T is an output torque, K is a torque constant of the motor, is a flux linkage, is a power factor of the motor.

[0013] The present application discloses a kind of electric vehicle permanent magnet synchronous motor control algorithm system, including algorithm system, the algorithm system includes sliding mode observer algorithm module and parameter algorithm module; Sliding mode observer algorithm module controls calculation to permanent magnet synchronous motor, parameter algorithm module calculates the relevant parameters of permanent magnet synchronous motor.

[0014] As a preferred technical solution of the present application, the sliding mode observer algorithm module includes sliding mode control algorithm submodule and sliding mode observer; Sliding mode control algorithm submodule estimates the position information of rotor by real-time observation to the current and voltage of PMSM using sliding mode variable structure method, and sliding mode observer realizes high-precision speed and position estimation without relying on mechanical sensor.

[0015] As a preferred technical solution of the present application, the parameter algorithm module includes current calculation submodule, voltage calculation submodule, rotor electric angle calculation submodule and three-phase proportion calculation submodule; Current calculation submodule calculates the current of permanent magnet synchronous motor, voltage calculation submodule calculates the voltage of permanent magnet synchronous motor, rotor electric angle calculation submodule calculates the rotor angle of permanent magnet synchronous motor, and three-phase proportion calculation submodule calculates the three-phase proportion of permanent magnet synchronous motor.

[0016] Compared with prior art, the present application has the following beneficial effects: 1. The algorithm estimates the rotor position information by real-time observation of the current and voltage of the PMSM using the sliding mode variable structure method, reduces the dependence on traditional mechanical sensors, effectively filters out noise during observation, and has strong robustness, ensuring stable operation of the system in complex environments. 2. The phase-locked loop in the observer calculates the rotor speed and angle information from the current and voltage signals of the motor, and accurately tracks the position and speed during motor operation. This sliding mode observer based on speed sensorless, combined with the optimization design of saturation function, enables high-precision speed and position estimation without relying on mechanical sensors, reduces the hardware complexity of the system, and improves the dynamic response speed and anti-interference ability. 3. The sliding mode control algorithm is combined with vector control to dynamically adjust the control parameters, allowing the system to quickly respond to external disturbances, reduce speed fluctuations, and improve the steady-state and dynamic performance of the motor. The improved vector control algorithm maintains system stability while significantly improving dynamic response performance and reducing overshoot and oscillation. BRIEF DESCRIPTION OF DRAWINGS

[0017] Fig. 1 The figure is a schematic diagram of the architecture of the algorithm system of the present application. Fig. 2 The figure is a schematic diagram of the architecture of the sliding mode observer algorithm module of the present application. Fig. 3 The figure is a schematic diagram of the architecture of the parameter algorithm module of the present application. DETAILED DESCRIPTION

[0018] The technical solutions in the embodiments of the present application will be described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0019] Please refer to Figs. 1-3 The present application provides a control algorithm for a permanent magnet synchronous motor of an electric vehicle, which includes a control algorithm, the control algorithm including a sliding mode observer algorithm, current calculation, voltage calculation, rotor electric angle calculation, and three-phase proportion calculation.

[0020] The sliding mode observer algorithm is provided with back electromotive force Ealpha and Ebeta to obtain the inverse tangent, which converts the dq coordinate system in vector control to the alpha-beta two-phase stationary coordinate system. The voltage equation of the two-phase stationary coordinate system is as follows: , The expression of the back electromotive force is as follows: , The motor current model contains the ordinary differential equation calculation as follows: , The current equation calculation formula in the voltage model is as follows: , According to the motor model, the sliding mode observer model of the same order and format is established, and the calculation formula is as follows: , The back electromotive force expression is as follows: , The error equation expression is as follows: .

[0021] The current calculation is the stator phase current, and the calculation formula is as follows: , Where i d is the direct-axis current output value, i q is the alternating current output value, and I s is the stator phase current.

[0022] The voltage calculation is specifically the quadrature axis voltage expected value, and the calculation formula is as follows: , σ is the load angle, is the direct-axis voltage expected value, is the quadrature axis voltage expected value.

[0023] The rotor electric angle calculation is specifically: , Where f is the power frequency, and p is the pole pair number of the motor.

[0024] The three-phase proportion calculation formula is as follows: , Where Ia is the a-phase current, P is the pole pair number of the motor, T is the output torque, K is the torque constant of the motor, is the flux linkage, is the power factor of the motor.

[0025] The application relates to a permanent magnet synchronous motor control algorithm system for an electric vehicle, which comprises an algorithm system, the algorithm system comprising a sliding mode observer algorithm module and a parameter algorithm module. The sliding mode observer algorithm module controls the permanent magnet synchronous motor, and the parameter algorithm module calculates the related parameters of the permanent magnet synchronous motor.

[0026] The sliding mode observer algorithm module comprises a sliding mode control algorithm submodule and a sliding mode observer; The sliding mode control algorithm submodule estimates the position information of the rotor by real-time observation of the current and voltage of the PMSM using a sliding mode variable structure method, and the sliding mode observer realizes high-precision speed and position estimation without relying on mechanical sensors.

[0027] The parameter algorithm module comprises a current calculation submodule, a voltage calculation submodule, a rotor electric angle calculation submodule and a three-phase proportion calculation submodule; The current calculation submodule calculates the current of the permanent magnet synchronous motor, the voltage calculation submodule calculates the voltage of the permanent magnet synchronous motor, the rotor electric angle calculation submodule calculates the rotor angle of the permanent magnet synchronous motor, and the three-phase proportion calculation submodule calculates the three-phase proportion of the permanent magnet synchronous motor.

[0028] In the present application, the sliding mode control algorithm submodule estimates the position information of the rotor by real-time observation of the current and voltage of the PMSM using a sliding mode variable structure method, and the sliding mode observer realizes high-precision speed and position estimation without relying on mechanical sensors, the current calculation submodule calculates the current of the permanent magnet synchronous motor, the voltage calculation submodule calculates the voltage of the permanent magnet synchronous motor, the rotor electric angle calculation submodule calculates the rotor angle of the permanent magnet synchronous motor, and the three-phase proportion calculation submodule calculates the three-phase proportion of the permanent magnet synchronous motor, and precise control of the permanent magnet synchronous motor is realized according to the calculation results.

[0029] Although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can modify the technical solutions described in the foregoing embodiments, or make equivalent replacements to some of the technical features, and any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. An electric vehicle permanent magnet synchronous motor control algorithm comprising a control algorithm, characterized in that: The control algorithm comprises a sliding mode observer algorithm, current calculation, voltage calculation, rotor electric angle calculation and three-phase proportion calculation.

2. The control algorithm of a permanent magnet synchronous motor for an electric vehicle according to claim 1, characterized in that: The sliding mode observer algorithm is provided with back electromotive force Ealpha and Ebeta to obtain an inverse tangent, so as to convert the dq coordinate system in vector control to an alpha-beta two-phase stationary coordinate system, and the voltage equation of the two-phase stationary coordinate system is as follows: ， The expression of the back electromotive force is as follows: ， The motor current model comprises a constant differential equation calculation as follows: ， The current equation calculation formula in the voltage model is as follows: ， According to the motor model, a sliding mode observer model is established in an equal order and format, and the calculation formula is as follows: ， The expression of the back electromotive force is as follows: ， The error equation expression is as follows: 。 3. The control algorithm of a permanent magnet synchronous motor for an electric vehicle according to claim 1, characterized in that: The current calculation is a stator phase current, and the calculation formula is as follows: ， where i d is the direct axis current output value, i q is the alternating current output value, I s is the stator phase current.

4. The control algorithm of a permanent magnet synchronous motor for an electric vehicle according to claim 1, characterized in that: The voltage calculation is specifically a quadrature axis voltage expected value, and the calculation formula is as follows: ， σ is the load angle, is the direct-axis voltage reference value, is the quadrature-axis voltage reference value.

5. The control algorithm of a permanent magnet synchronous motor for an electric vehicle according to claim 1, characterized in that: The rotor electric angle calculation is specifically as follows: ， Wherein f is a power supply frequency, and p is a pole pair number of the motor.

6. The control algorithm of a permanent magnet synchronous motor for an electric vehicle according to claim 1, characterized in that: The three-phase proportion calculation formula is as follows: ， where Ia is the a-phase current, P is the number of pole pairs of the motor, T is the output torque, K is the torque constant of the motor, is the flux linkage, is the power factor of the motor.

7. A control algorithm system for a permanent magnet synchronous motor of an electric vehicle according to any one of claims 1-6, comprising an algorithm system, characterized by: The algorithm system comprises a sliding mode observer algorithm module and a parameter algorithm module. The sliding mode observer algorithm module performs control calculation on the permanent magnet synchronous motor, and the parameter algorithm module performs calculation on related parameters of the permanent magnet synchronous motor.

8. The control algorithm system of a permanent magnet synchronous motor for an electric vehicle according to claim 7, characterized in that: The sliding mode observer algorithm module comprises a sliding mode control algorithm submodule and a sliding mode observer. The sliding mode control algorithm submodule estimates the rotor position information by real-time observation of the current and voltage of the PMSM by using a sliding mode variable structure method, and the sliding mode observer realizes high-precision speed and position estimation without relying on mechanical sensors.

9. The control algorithm system for permanent magnet synchronous motor of electric vehicle according to claim 7, characterized in that: The parameter algorithm module comprises a current calculation submodule, a voltage calculation submodule, a rotor electric angle calculation submodule and a three-phase proportion calculation submodule. The current calculation submodule calculates the current of the permanent magnet synchronous motor, the voltage calculation submodule calculates the voltage of the permanent magnet synchronous motor, the rotor electric angle calculation submodule calculates the rotor angle of the permanent magnet synchronous motor, and the three-phase proportion calculation submodule calculates the three-phase proportion of the permanent magnet synchronous motor.

Images