Comparison of Short-Circuit Current Control of Resonant Switched-Capacitor Converter

Short-circuit fault is one of the serious challenges of resonant switched-capacitor converters (RSCC). By comparing the frequency control and duty ratio control, a combination short-circuit current control strategy is proposed to suppress the RSCC short-circuit current and transient oscillation. Based on the analysis of RSCC operation principle and short-circuit mechanism, the operation performances under frequency control and duty ratio control are compared. Then the theoretical analysis of the proposed combination control is presented, and the resonant characteristics are depicted with state trajectory analysis. In addition, the soft switching conditions of three control strategies are discussed. Finally, the feasibility and correctness of the proposed method are verified through experiments. The results show that the combination control strategy avoids narrow pulse issue and achieves better short-circuit current suppressing performance. Moreover, soft switching is realized and the resonant current oscillation during transient process is alleviated.