Experimental research on back EMF zero crossing detection method for novel transverse flux permanent magnet motor

Back EMF zero crossing detection method has been successfully applied to sensorless control of conventional brushless DC motor. This paper highlights the differences in its implementation for novel transverse flux permanent magnet motor (TFPMM), as regards additional detection error. The reasons for long commutation process in novel TFPMM have been discussed to indicate much wider voltage spikes, which is the essence of additional detection error. It has been also shown from experimental results that the zero crossing point of filtered phase voltage is ahead of that of corresponding back EMF. To determine the phase compensation for rotor-position-detection error, the corresponding phase difference is presented under varying load torque conditions.