Study On A Novel Permanent Magnet Assisted Synchronous Reluctance Motor With Asymmetric Rotor

Permanent magnet motors are widely used because of their high power density,high torque output,and high efficiency,etc.,they are widely used in various fields.Although the rare earth permanent magnet material has excellent performance,its price fluctuation is large.This makes the permanent magnet-assisted synchronous reluctance motor become a research hotspot in recent years.This article refers to it simply as PMA-synRM.The traditional PMA-synRM electromagnetic torque consists of permanent magnet torque and reluctance torque.They vary with the phase angle of the current according to the sinusoidal law,but the periods are different,and the current phase angles corresponding to the respective peaks are different.If the peaks of them can be brought close to each other,the electromagnetic torque can be increased.In order to achieve control of the relationship between the reluctance torque and the phase of the permanent magnet torque,this paper expands the following work:(1)In this paper,the mathematical model of asymmetric rotor PMA-synRM in d-q coordinate system is established by introducing the orthogonal axis component of permanent magnet flux linkage.And the voltage equation,current equation,torque equation,and flux equation are given.(2)Based on the mathematical model in the d-q coordinate system,this paper first designs an 8-pole asymmetric rotor PMA-synRM and performs finite element analysis.The analysis results show that the 8-pole non-pair rotor PMA-synRM realizes the change of the superposition relationship between reluctance torque and permanent magnet torque,which proves the correctness of the mathematical model.(3)Considering that the motor described above has a permanent magnet space on the rotor side,the frequency of the power supply is high.To this end,this paper has designed a 4-pole asymmetric rotor PMA-synRM motor.In this model,an asymmetric rotor PMA-synRM with a "decentralized Halbach array" is proposed.The model changes the superposition relationship between reluctance torque and permanent magnet torque,and the position of the permanent magnet does not occupy the q-axis magnetic circuit.The finite element analysis results show that the 4-pole asymmetric rotor PMA-synRM of this "decentralized Halbach array" has a certain improvement in electromagnetic torque and efficiency compared to the traditional PMA-synRM.