A Control Strategy for BLDC Motor Based on Terminal Voltage

Brushless direct current (BLDC) motor is widely used in robots, auto-guided vehicle fields because of its simple structure, high reliability, wide speed range and easy maintenance. The accuracy of the commutation is very important for high performance BLDC control. To precisely obtain the commutation signal, this paper proposes a novel control method based on the terminal voltage of BLDC. The method considers the influence of the irrational factors of the driver and motor on the accuracy of zero-crossing point (ZCP). Firstly, the time corresponding to three consecutive ZCP intervals of 180° is used as the time base of the phase compensation, and the ZCP is calculated by sampling the suspended phase terminal voltage. According to the obtained zero crossing signal and time base, the commutation signal can be determined. Finally, a closed-loop correction strategy is adopted to eliminate commutation errors. The simulation result proves the feasibility of this scheme.