Characteristic Analysis and Loop Control of Three-phase Series Capacitor Buck Converter

In this paper, a TSD converter is proposed to improve the voltage conversion ratio and reduce the switching voltage stress by series capacitors to solve the shortcomings of the traditional Buck converter in high conversion ratio scenarios. The small signal model is established based on the switching state averaging, and the stability and dynamic performance of the system are optimized by PID compensation. According to the simulation results, the TSD converter realizes automatic inductor current balance in 48V-1V conversion and stable capacitor voltage, with 49mV and 25mV as the output voltage undershoot and overshoot respectively under ±5A load transition, which proves the superiority of the designed loop control.