梯形永磁体盘式无铁心电机的设计与研究

Design and study of disc coreless motor with trapezoidal permanent magnet

针对永磁盘式无铁心同步电机的轴向磁场结构,在现有Halbach永磁阵列的基础上,提出一种梯形结构永磁体阵列。详细阐述该电机的结构与优点,利用有限元方法研究了不同梯形结构永磁体阵列对气隙磁密的影响,根据气隙磁场中的谐波含量及空载反电势畸变率选取最优转子结构。该结构在保证与传统结构永磁体材料用量相当的前提下,有效提高气隙磁密的基波,降低谐波含量。由于轴向磁场结构的特殊性,给出该电机的设计规则,如磁极尺寸和导体占空比的确定。计算了电机在负载工况下不同定子电流对交直轴电感的影响,为该类电机的设计提供了一定的参考价值。

A trapezoidal permanent magnetic array is proposed based on the existing Halbach permanent magnetic array, aiming at the axial magnetic field of permanent magnetic disc coreless synchronous mo- tor. The structure and advantages of the motor were shown. The influence of different trapezoidal perma- nent magnetic arrays on the air gap flux density was studied by finite element method. The optimal rotor structure was proposed according to the harmonic content in the air gap magnetic field and no-load back electromotive force （EMF） distortion rate. The fundamental was heightened and harmonic content was decreased in air gap flux density, with no change of permanent magnetic volume comparing with traditional structure. Considering the characteristic of axial magnetic field, such as ensuring of the parameters of magnetic poles and conductor duty cycle, the design rule of motor was provided. The influence of different stator currents on the d-q axis inductance was calculated under load condition, which offers reference value for the design of this kind of motor.