Research On Flux-weakening Strategy For PMSM

Permanent magnet synchronous motors(PMSMs)have the advantages of high energy density,simple structure,good starting and speed-regulation performance.They are commonly used in electric power steering systems(EPS).The speed range of the steering wheel controlled by the driver is very wide.In order to obtain stable assistance in a wide range of speeds,it is of great significance to study the weak field expansion of permanent magnet synchronous motors to improve steering performance and driving experience.This dissertarion first introduces the basic principles of flux-weakening control for PMSMs.Then the two flux-weakening control methods based on voltage feedback:negative i_dcompensation and stator-current leading angle are compared.In this dissertation:In order to enhance the robustness of the system,simplify the parameter settings,reduce the current fluctuations in the flux-weakening transition region,the flux-weakening and current decoupling part are optimized.The simulation results show that the improved flux-weakening control strategy can effectively shorten the speed and current response time of the flux-weakening transition region,and optimize the current fluctuation to a certain extent.Finally,an experimental platform is set up,the controller and driver board are designed,and programming of flux-weakening control strategy is completed.Experiments were performed under no-load,light-load and full-load conditions,and the effectiveness of the improved stator current leading angle flux-weakening control strategy was verified.