Advanced sensorless drive technique for multiphase BLDC Motors

The main purpose of this paper is to develop a new position sensorless drive method for multiphase brushless DC (BLDC) motors. A BLDC motor with higher number of phases has several advantages. It can reduce the ampere-turns and torque pulsation and increase the efficiency and iron utilization. Also, it is well used for fault tolerant motor drive systems as in military applications. With the developed speed-independent, new position information that is computed in a microprocessor, highly accurate sensorless operation can be realized for multiphase BLDC motors. The operational principle of the proposed sensorless drive for multiphase BLDC motors is theoretically analyzed and the performance is demonstrated by computer simulations and experiments in detail.