永磁无刷直流电机磁阻转矩的解析计算方法

ANALYTICAL CALCULATION OF COGGING TORQUE IN BRUSHLESS DC MOTOR

该文利用许-可变换,构造了考虑齿槽效应的等效气隙磁导函数,结合偏微分方程的解析算法,计算出等效气隙内任意半径上的气隙磁通密度分布,由此提出了一种永磁无刷直流电机磁阻转矩的解析计算方法,其计算结果与有限元计算结果对比,转矩波形基本吻合,证明此方法是正确的、可靠的;同时该方法可应用于磁极分段移位、齿面加辅助凹槽、移动相邻磁极等结构的磁阻转矩的计算,为永磁无刷直流电机设计和优化提供了基本分析手段。

With the Schwarz-Christoffel Transformation,the equivalent air-gap permeance function is derived,considering the slots in stator core. Based on the analyticalgorithm of the partial differential equations , the distribution of the air-gap magnetic flux density at an arbitrary radius in the equivalent air-gap is determined. Hence, this paper presents a calculation method for the cogging torque of permanent magnet brushless DC motors. The obtained torque waveforms areapproximately the same as that calculated by 2D finite element method , which proves the accuracy and efficiency of the method. This method can be applied to analyze thecases ,such as staggering two pole stacks with a angulardisplacement, notching the teeth and shifting adjacent poles as well. This present work can functions as a powerful tool for the analysis and the optimizing design of the permanent magnet brushless DC motors.