High-Frequency Injection-Based Sensorless Control for a General Five-Phase BLDC Motor Incorporating System Delay and Phase Resistance

This paper investigates the sensorless control of a general Five-phase permanent magnet brushless DC (5 Phi-BLDC) motor working at the low speeds. High frequency (HF) injection-based sensorless control is most popular, however, the system delay and stator resistance could deteriorate the sensorless control performance. In this paper, an HF model of 5 Phi BLDCs at frequency-domain is primarily established as a replacement over the conventional static model, and an interpretation from the sinusoidal internal model is carried out to direct the sensorless control implementation. Accordingly, the measured d-axis HF current, which is typically neglected in the conventional method, is reused to demodulate the position angular information from the measured q-axis HF current. The proposed sensorless control is performed on a 5 Phi BLDC drive, and experimental results confirm the effectiveness of this method while comparing its performance with the conventional method.