Research On Vector Control Strategy Of Permanent Magnet Synchronous Motor Based On Hybrid Multi-model Design

Permanent magnet synchronous motor(PMSM)has been widely used in many industrial fields due to its advantages of high power density,high efficiency and compact structure.High speed permanent magnet synchronous motor(PMSM)is the future development trend,which can not only improve the application range of the motor,but also improve its power density.However,the high speed will lead to the rise of the back electromotive force,even exceeding the voltage limit allowed by the inverter.Therefore,it is necessary to study the weak magnetic control strategy of PMSM to improve the speed range.At the same time,the traditional PMSM needs to install a position sensor at the end of the rotor shaft to sample the rotor speed and position to complete the closed-loop control of the motor.However,the use of position sensor not only increases the cost and volume space of the motor,but also reduces the reliability of the system and increases the potential failure probability.Therefore,in some special cases,the motor is required to run normally without position sensor to meet the actual demand.Aiming at the above two application problems,the weak magnetic expansion control strategy and sensorless control strategy of PMSM are studied in this paper.In the part of weak magnetic control,the improved variable quad-axis single current weak magnetic control model is modeled and simulated.In the sensorless control part,the high frequency pulse injection method and the improved sliding mode observer control strategy are modeled and simulated.Specifically,this paper includes the following contents:1.Carrying out mathematical modeling of permanent magnet synchronous motor,studying the principle of coordinate transformation,voltage feedforward decoupling and SVPWM,and builting a PMSM Matlab/Simulink simulation model.2.The principle and mathematical model of MTPA control and weak-magnetic control of permanent magnet synchronous motor are studied.Three traditional weak-magnetic control methods and their advantages and disadvantages are compared and analyzed.An improved single current control strategy for variable quadrature axis voltage is proposed and verified by simulation.3.The sensorless control strategy of PMSM is studied,and the control principle of pulse high-frequency injection method and rotary high-frequency injection method in low speed domain and sliding mode observer control principle in high speed domain are mainly analyzed.In order to realize the sensorless control strategy in the full speed domain,a hybrid control strategy combining pulse vibration high frequency injection method and sliding mode observer method is proposed.Sigmoid function is proposed to suppress chattering of sliding mode observer.To solve the problem of phase delay and error caused by traditional arctangent function rotor position extraction,a position signal extraction method based on phase locked loop technology is proposed.In order to realize the smooth transition between the two algorithms in the full velocity segment,In this paper,a weighted function is proposed to solve the problem of control strategy switching in speed transition region.Finally,the control software and hardware system of PMSM on the experimental platform are introduced.In this paper,the TMS320F28062 DSP control chip based on TI is experimentally verified on a 30 k W permanent magnet synchronous motor,and the experiments with load and without load are carried out respectively.The experimental results show that the proposed control strategy has good dynamic response performance and loading performance,and can meet the practical application requirements.