A Novel Doubly Salient Electromagnetic Motor Drive System With Small Bus Capacitor

This article proposes a small capacitor drive system for doubly salient electromagnetic motor (DSEM), including the drive circuit and its corresponding control strategy. By taking advantage of the characteristic that the inductor current cannot change abruptly, the system further utilizes ac source to charge the bus capacitor, thereby increasing the maximum voltage of the bus capacitor. Additionally, a bus switch control strategy suitable for this circuit is proposed to reduce the discharge time and energy required by the bus capacitor, thus reducing the required bus capacitance of the system. Compared to the traditional motor drive systems, the proposed system allows for the use of film capacitors instead of electrolytic capacitors, resulting in a reduced system volume and improved reliability and power density. Moreover, compared to the existing researches, the proposed system can more fully utilize the ac source to charge the bus capacitor, thereby improving the efficiency of the ac source, and simultaneously enhancing the power quality of the ac source. The experiments on a 12/8-pole DSEM validate the correctness and feasibility of the proposed system.