Position Sensorless Direct Power Control of Brushless DC Motor Drive using Unknown Input Speed Observer

Abstract

This paper proposes the speed control of brushless DC (BLDC) motor via direct power control (DPC) method as a novel and effective strategy in electrical drives applications. The DPC has some advantages rather than other control methods of BLDC motor including simpler control algorithm and faster dynamic response. In proposed BLDC motor drive based on DPC strategy, space vector modulation (SVM) voltage source inverter is employed. To enhance the drive reliability, a position sensorless strategy has been used for rotor position detection and current commutation. In developed sensorless strategy, an observer has been designed to predict the phase back-emf voltages using line voltages and currents. So, there is no need to position sensors and the cost is reduced. The performance of proposed sensorless DPC method has been verified via some simulations in Matlab under different speed and torque references.