Sensorless Starting and Commutation Error Compensation Strategy for High-Speed Brushless DC Motors Based on Quasi-Current Source Inverter

Aiming at the problem of incorrect switching caused by speed estimation deviation during the sensorless starting process of high-speed brushless DC motors (BLDCM), this paper proposes a constant-current frequency-up acceleration starting method based on quasi-current source inverter (QCSI). This method controls the inductor current to keep constant so that the motor can be accelerated with constant torque and designs the acceleration step number to realize the self-synchronous operation switching of the motor. In addition, a commutation error compensation strategy considering voltage clamping is proposed for the high-speed BLDCM driven by QCSI. This strategy calculates the phase lead angle caused by diode voltage clamping, perfects the source of commutation error, and improves the accuracy of the commutation error model, so as to obtain more accurate commutation error compensation angle. Experimental results show that the proposed starting method can realize reliable three-stage starting of the motor, and the parameter design is simple and convenient for engineering applications. In addition, the proposed compensation strategy enables fast and accurate commutation correction for the motor under both dynamic and steady-state conditions. It also achieves phase synchronization between the motor's back electromotive force and phase current, thereby improving the torque-to-current ratio.