Sensorless brushless DC control using a current waveform anomaly

This paper develops a new method of sensorless control for brushless DC (BLDC) machines. The new sensorless control method utilizes relative rotor position feedback information which is extracted from the hysteresis chopping of the sensed phase current waveforms in a nonsalient, trapezoidal back-EMF, surface-mounted permanent-magnet BLDC. Details of the new method of sensorless brushless DC control are revealed. The existence and uniqueness of the hysteresis waveform feedback information is shown. A simulation of two modes of the new sensorless control and experimental validation are performed.