Research on Two Design Approaches of Permanent Magnet Width Modulation Secondary for Permanent Magnet Linear Synchronous Motor

Big pole pitches of high-speed Permanent Magnet Linear Synchronous Motors (PMLSMs) cause many problems. Permanent Magnet (PM) width modulation secondary is an excellent solution to these problems, and conducive to the suppression of thrust ripple. This paper studies two design approaches of this novel secondary: equal area method and triangular modulation method. Firstly, the modeling of PM width modulation secondary for high-speed PMLSM is studied, the schemes of equal area method and triangular modulation method are presented. Furthermore, thrust features of PMLSMs with PM width modulation secondary, based on the two methods respectively, are analyzed and compared. A prototype is manufactured to verify the feasibility of PM width modulation secondary. The results provide base data of PM width modulation secondary for highspeed PMLSM.