Research on Sensorless Control Method of Permanent Magnet DC Linear Motor Based on Line Back EMF

A sensorless commutation control method based on the zero crossing principle of line back EMF is proposed for permanent magnet DC linear motor with distortion of opposite EMF. Through qualitative analysis of waveform and quantitative derivation of series theory formula, it is proved that even if the opposite potential is distorted, the zero point of line back potential is still consistent with the actual electronic commutation point of the system. At the same time, in order to avoid missing the zero point of line back EMF, a commutation control method based on s function is constructed. The simulation results show that the method meets the system requirements.