A Variable Sampling-Frequency-Based Commutation Delay Compensation Method for High-Speed Doubly Salient Motor Considering Speed Fluctuation

The doubly salient motor (DSM) is a suitable candidate for the high-speed drive system due to its robust structure and adjustable magnet field. However, the commutation delay at high-speed operation will deteriorate the current performance and thereby degrade the torque capability of the DSM drive system. In this article, the commutation delay compensation (CDC) method based on variable sampling frequency is proposed for the high-speed DSM drive system. First, the production mechanism of commutation delay is analyzed and the commutation delay is classified into two categories. Then, in the proposed CDC method, the angle difference between the sampled rotor position and the given commutation angle is calculated. The sampling frequency is adjusted in real time based on the angle difference and the criterion considering the influence of speed fluctuation. The commutation delay characteristics are analyzed through simulation results. Finally, the proposed CDC method is implemented on a high-speed DSM drive system. The experiment of the proposed CDC method is carried out on the condition of steady-state, different speeds, reference speed step change, and variable load torque. The experimental results indicate that the proposed CDC method can effectively compensate the commutation delay and enhance the torque capability of the high-speed DSM drive system.