Halbach阵列永磁同步直线电机边端力最小化研究

Research on Minimizing End Force of Permanent Magnet Linear Synchronous Motor with Halbach Array

为了最小化由边端效应引起的永磁同步直线电机的推力波动,分析了永磁直线电机边端力产生的原因。以Halbach阵列永磁直线电机为例,用两种解析方法推导出最优初级长度。用基于傅里叶极数的解析方法推导得出了最小边端力下的初级长度计算公式;并用等效磁化电流法求出空载气隙磁密,用麦克斯韦张量法求出直线电机初级所受边端力,根据解析式分析边端力特性,并推导出边端力最小时的初级长度表达式。通过有限元验证了初级长度计算公式的正确性,结果表明提出的最优初级长度是可行的,可以有效降低永磁直线电机的边端力,从而抑制永磁直线电机的推力波动。

For reducing thrust ripple of permanent magnet linear synchronous motors （PMLSM） resulting from end effect,the causes of the end force of permanent magnet motor were analyzed. Took a permanent magnet linear motor with Halbach array as an example, two kinds of analytic methods were used to obtain the optimal primary length. A analytic meth- od based on Fourier series was applied to gain the primary length formula under the minimal end force. The equivalent mag- netization current method was applied to obtain the no load air-gap magnetic flux density, the Maxwell tensor method was applied to calculate the end force of the primary of the hnear motor. According to the formula, characters of the end force were analysed, and the optimal primary length formula under the minimal end force was obtained, which was identical with the one got from the first method. The correctness of the calculation formula of primary length was verified by finite element method, and the results indicated that the optimal primary length could reduce the end force and the thrust ripple effectively.