A cost-effective ripple-off thrust drive for PMLSM automatic door on non-ideal sinusoidal back-emf

Permanent Magnet Linear Synchronous Motor (PMLSM) driving will bring many merits for the automatic door system. But in reality it is very hard for the designed and constructed PMSM to produce the ideal sinusoidal back electromotive force (back-emf), thus resulting in higher torque ripple by using conventional vector control scheme, especially for low-cost machines. To cancel the torque ripple, this paper analyzes the instantaneous electromagnetic torque production with Park-like transformation and presents a cost-effective method to generate constant propulsion with optimal current commands in a lookup table offline calculated on non-ideal sinusoidal back-emf.