Research On Current Distribution Strategy Of Permanent Magnet Synchronous Motor With Wide-range Speed Regulation

With the acceleration of industrialization and urbanization,the resource and environmental issues have become an important bottleneck restricting China’s economic and social development.The work of energy conservation and emission reduction cannot be delayed.In this context,new energy vehicles have developed rapidly.The permanent magnet synchronous motor(PMSM)is widely used in electric vehicle drive systems with high efficiency,high power density and high stability.Based on the requirements of high efficiency,high dynamic response and strong robustness of electric vehicle drive system,this thesis studies the current distribution strategy of constant torque zone and field weakening zone for PMSM with wide-range speed regulation.In the constant torque region,the inherent characteristics of maximum torque per ampere(MTPA)for PMSM are analyzed in this thesis.Based on the idea of traditional virtual signal injection control(VSIC),two MTPA control strategies with dual signal synchronous virtual injection are proposed.The new scheme aims to remove the filters in the traditional signal processing structure and propose a new signal processing method by injecting a specific double sinusoidal/DC signal in the stator current vector angle and observing the instantaneous power/torque of the motor synchronously.This strategy greatly enhances the system’s response speed and achieves precise MTPA control.In the field weakening region,a current disturbance decoupling compensation scheme based on Proportional-Integral-Observer(PIO)is proposed for the current dynamic coupling and back electromotive force(EMF)problems at high speed.Through PIO,the current coupling,back EMF and external disturbance are observed and compensated synchronously,which improves the anti-interference ability of the system.Then the traditional voltage feedback field weakening strategy is improved by combining with the simplified formula calculation,further speeding up the follow-up speed of the current track.Based on the theoretical analysis,the algorithm proposed in this thesis is verified based on MATLAB/Simulink,and a PMSM drive system is designed.Aiming at the torque maximization output,a complete PMSM current distribution scheme with wide-range speed regulation is designed and implemented physically by combining the proposed control strategy of constant torque zone and the field weakening zone.The feasibility and stability of the proposed strategy are verified by simulation and experimental comparison.The final part of this thesis is the study conclusion and adaptation prospect.