Modeling and Closed-Loop Control of Three-Port Isolated Current-Fed Resonant DC–DC Converter

The power decoupling three-port isolated current-fed resonant dc–dc converter realizes the power decoupling of each port at the topology level, reduces the control complexity, and ensures the zero instantaneous power of the standby port and high operation efficiency. In this article, the closed-loop control of the transfer power of each port is researched for the first time. First, a simplified single closed-loop control strategy of low-voltage side (LVS) port current is proposed to realize the closed-loop control of the transfer power. Then, the small-signal model is established and the parameters of the closed-loop controllers are designed. In addition, the transient time-domain characteristics of the voltage of the inner dc capacitor and the resonant current are analyzed and it is proven that there is no issue of transient overshoot or oscillation even when these variables are not under closed-loop control. The correctness and feasibility of the proposed closed-loop control strategy and parameters design are verified by the experimental results.