Study on the Control Strategy of Input-Series Output-Parallel Phase-Shifted Full Bridge Converter Based on Virtual DC Motor

This paper studied the input-series output-parallel (ISOP) phase-shifted full bridge converter and analyzed the input and output characteristics of the ISOP converter. Then, a three-loop control strategy based on virtual DC motor control is proposed, and its introduction to virtual damping resistance can better suppress the fluctuation of input voltage. A small-signal model is also developed for the ISOP converter, and stability analysis is performed for each control loop. The stability of the ISOP system under this control strategy is given by the analysis of the Bode and Nyquist diagrams. Finally, the phase-shifted full-bridge converter is selected as the base unit, and the simulation results are used to verify the input voltage sharing and output current sharing with the system under the three-loop control strategy based on virtual DC motor control.