Research On Predictive Current Control Method Of Permanent Magnet Synchronous Motor

With the widespread application of permanent magnet synchronous motor(PMSM),demands on the performance of PMSM drive systems are becoming stricter in some applications like electric vehicle,robotics etc.As a central part of the drive system,the current control directly decides the transient dynamics of the motor,thus being essential to high performance drives.For sufficiently exploiting the physical dynamics of the motor,numerous model-based current control methods have been proposed,within which the predictive current control appeals more academic research.In this thesis,the deadbeat predictive current control(DBPCC)in interior permanent magnet motor(IPMSM)is studied.The linearized model of IPMSM is derived according to its electromagnetic dynamics and coordinate transform theory,this model is referenced by the latter current controller design.The rotor field oriented control structure is then constructed,elaboration on the principle and implementation of some important elements.On the acquisition of initial rotor position,two commonly used methods are studied.The rotor pre-orientation is analyzed in terms of its process based on actually measured results and constraints for its effectiveness is derived.The initial rotor position identification at standstill based on high frequency voltage injection is studied and modification on the observer structure is proposed.Experiment on the initial position identification is performed and results verify the short detection time and high accuracy of the identification method.To overcome inherent drawbacks of the deadbeat predictive current controller especially the high sensitivity to parameter perturbation,the input delay based disturbance estimation is adopted and a low pass filter is introduced to avoid instability caused by disturbance compensation.As a further improvement on robustness,the feedforward control mixed with feedback control is adopted to realize the two-degreeof-freedom control structure.Simplified system modeling and controller performance analysis are conducted then.Experiments on the IPMSM current control based on the improved current controller is performed and results confirm that the controller performance is improved significantly with optimized parameter settings.