Indirect back EMF detection based sensorless operation of PMBLDC motor drive

In this paper, a position sensorless permanent magnet brushless direct current (PMBLDC) motor drive is presented. For realization of sensorless operation, zero crossing of back emf is detected. In order to generate the proper firing pulses for commutation of inverter circuit and to remove the noise from the back emf signals, low pass filters are used. The complete drive system is modeled in the MATLAB/Simulink software. The sensorless drive is tested for various operating conditions.