Low cost and real time electronic speed controller of position sensorless brushless DC motor

Brushless DC (BDC) motors are widely used in aerospace applications because of their high power to weight ratio, low maintenance and reliable operation over long periods of time. These advantages also make them preferred over brushed DC motors for several other applications. But the requirement of an electronic speed controller for commutation and customization for specific applications makes BDC a costly affair. This paper presents a low cost and real time electronic speed controller for BDC motors. The motor is started using the motor phase saturation inductance change method. Further control of the motor is established by monitoring the back emf zero crossing as a feedback. In addition, MATLAB simulink based simulations have been performed to analyse the circuit performance under real time input conditions.