A Simple Position Sensorless Control Strategy for Radial-Flux Brushless DC Motor Drives Using Single Current Sensor

Reducing the cost of the motor drive is desirable for low cost applications. A simple and cost-effective position sensorless control for radial-flux permanent magnet brushless DC (BLDC) motor drives using single current sensor is proposed in this paper. It is based on the generation of quasi-square current waveforms, using only one current controller for the three phases. Unlike the conventional methods, the proposed method presents advantages such as very simple control scheme, without needing to triangular carrier modulation, and balanced phase currents. The proposed position sensorless technique is based on the detection of zero crossing points of three voltage functions that are derived from the difference between the lines’ voltage measured at the terminals of the motor. In order to improve the speed transient response of the BLDC motor and enhance the energy saving aspect of the system, it should enjoy a high quality dynamic response characteristic. Therefore, to realize these purposes, particle swarm optimization (PSO) has been proposed to regulate the proportional-integral-derivative (PID) parameters of the motor speed controller. The proposed control algorithm is particularly suitable for cost sensitive product such as air purifiers, air blowers, cooling fan, and related home applications. The effectiveness of the proposed system has been validated by comparative studies and simulation results.