Research On Virtual Signal Injection MTPA Control Method Of Interior Permanent Magnet Synchronous Motor

The Interior Permanent Magnet Synchronous Motor(IPMSM)has a convex pole characteristic,and the Maximum Torque per Ampere(MTPA)control is usually used to make full use of the reluctance torque,so as to achieve the control purpose of optimal operating efficiency.The conventional MTPA control method causes the MTPA operating point deviation due to the parameter change,while the high frequency signal injection MTPA control method can mitigate the effect of parameter change,but the method injects the actual high frequency current signal,so there is the problem of torque pulsation.To address this problem,this thesis focuses on the IPMSM-MTPA control system and adopts an improved virtual signal injection MTPA control method to fundamentally avoid the problem of actual torque pulsation in the high frequency signal injection method,and introduces a model reference adaptive parameter identification method to improve the accuracy of the electromagnetic torque equation and control system.First,the current research status of permanent magnet synchronous motor control,MTPA control and parameter identification is described,and the advantages and disadvantages of each method are compared.Meanwhile,the IPMSM mathematical model is derived,and the stator current distribution method of permanent magnet synchronous motor vector control and the operating characteristics of MTPA operating point are analyzed.Next,the working principle and design scheme of high frequency signal injection MTPA control are elaborated.By introducing a new MTPA reference system,an appropriate high frequency current signal is injected into it,and the connection between the torque pulsation components and the current vector angle is deduced in this coordinate system.The electromagnetic torque is first separated from the amplitude of the primary torque pulsation component by low-pass and high-pass filters,and then the correction angle is generated by the PI controller,so as to compensate the deviation of the MTPA operating point due to the parameter changes and achieve the purpose of real-time tracking of the MTPA estimation.The feasibility of the method is verified by simulation,while the problem of torque pulsation is pointed out.Then,the working principle and design scheme of virtual signal injection MTPA control are elaborated.By injecting high frequency current signals into the electromagnetic torque equation,the electromagnetic torque equation containing high frequency signals is constructed and filtered by low-pass and high-pass filters to obtain?T_e/?β,and then the current vector angle is obtained by PI controller to achieve the purpose of real-time tracking of MTPA estimation.The electromagnetic torque equation is analyzed to be influenced by the accuracy of the straight-axis inductance,especially for IPMSM with a small reluctance torque share.therefore,this thesis proposes a model referenced adaptive parameter identification method to obtain the straight-axis inductance value in real time to improve the accuracy of the electromagnetic torque equation and thus achieve high-precision MTPA control.This method does not depend on the design parameters of the motor and effectively avoids the problems of the high frequency signal injection method.The simulation results verify the feasibility and superiority of the proposed control method.Finally,the IPMSM drive control experiment platform is built with TMS320F28335 as the control core,the hardware diagram of the main circuit,power supply circuit,signal acquisition circuit and driver circuit is given,and the software flow chart of the main program and interrupt service subroutine is also given.Moreover,the experimental platform is tested and the results verify the correctness of the proposed method.