An Enhanced DC Preexcitation With Effective Flux-Linkage Control for the High-Power Induction Motor Drive System

This paper proposed an enhanced dc preexcitation for a variable-voltage variable-frequency-controlled induction motor drive system. Voltage vectors were adjusted according to the reactive component of the motor current, which promptly established the effective value of the motor flux linkage at the preexcitation stage and restrained its trajectory strictly as a round circle all through the starting process. The enhanced dc preexcitation control led to more negligible flux-linkage distortion, less torque vibration, and significantly smaller inrush current. Experiments on a 380-VAC/315-kW adjustable speed drive system validated the effectiveness of the proposed method.