Predictive Set Point Modulation Control for Onboard Supercapacitors of Catenary-Free Trams

Catenary-free trams have been considered a promising public transportation option for modern cities, where onboard supercapacitors are applied as the power source for the tram. Due to the frequent short-distance stops and drastic load changes, the DC bus exhibits significant voltage fluctuations, which affects the normal operation of loads. To address this challenge, in this paper, we propose a predictive set point modulation control for the onboard supercapacitors of catenary-free trams, where the DC bus voltage is predicted in real-time and the reference voltage of the closed-loop system is regulated accordingly to suppress the voltage overshooting. The system modeling of the onboard supercapacitors is presented first, and then the predictive set point modulation control is introduced in detail. A laboratory experimental platform is built to verify the effectiveness of the proposed method. Extensive experiment results show that the proposed method can effectively suppress the voltage fluctuations when compared with the classical control method.