MTPA Vector Control Of Permanent Magnet-assisted Synchronous Reluctance Motor Based On High-frequency Rotating Voltage Injection Parameter Identification

Permanent magnet assisted synchronous reluctance motor(PMaSynRM)improves torque density by embedding ferrite in the rotor magnetic barrier,which has the advantages of high efficiency,no rotor copper consumption and small torque ripple.Firstly,a reasonable current distribution algorithm can improve the efficiency and load capacity of the motor.Secondly,parameter identification can obtain reliable motor parameters to ensure the accuracy of the control algorithm.Meanwhile,speed sensorless control can greatly reduce the system cost and hardware complexity,and improve the reliability under complex working conditions.Therefore,this paper studies the maximum torque-current ratio control of PMaSynRM and the full-speed domain operation method without speed sensor-based control based on parameter identification.Firstly,the working principle of PMaSynRM is analyzed,and its mathematical model and equivalent circuit are established in the static coordinate system and rotating coordinate system.In order to solve the problem of constant D-axis flux control applied to PMaSynRM,the MTPA control method was used to optimize the stator current distribution,so that the dq axis current of the motor was restricted to the MTPA trajectory during steady operation,and the motor efficiency was improved.Secondly,the high frequency model of the motor and the salient pole effect generated by the high frequency signal are used,and the synchronous shafting filter is designed to extract the high frequency signal.Finally,the online identification and feedback of inductance parameters are realized,so as to improve the robustness of the system to the inductance uncertainty.Finally,a Butterworth bandpass filter is designed to extract rotor Angle and speed by high frequency signal injection in the low speed domain.In the middle and high speed domain,the cascaded structure of flux observer and phase-locked loop was constructed,and the accurate phase voltage was obtained by the phase-voltage reconstruction method with dead-time delay.Then,the sensorless speed control in the full speed domain of PMaSynRM was realized by designing a smooth switching algorithm between the low speed domain and the middle and high speed domain.An experimental prototype of PMaSynRM speed sensorless control was built and the software and hardware were designed.The speed sensorless control algorithm of PMaSynRM based on CCIAC and MTPA is implemented in the prototype.Experimental results show that the proposed method can well realize the control of PMaSynRM in full speed domain without speed sensor,smooth switching and maximum torque-current ratio control when the speed changes in a wide range,and solve the problem of performance degradation caused by the uncertainty of inductance.