基于开关谐振支路的电压自平衡型 ISOP 直流变压器

For the input-series output-parallel (ISOP) DC transformer, the input voltage balance control is an essential but complex design. An improved input-side voltage self-balancing topology of the DC transformer is proposed based on dual active bridge modules. By integrating the switched resonant branches between the neighboring modules, the topology achieves the input-side voltage self-balance without extra switching devices. By analyzing the current stress of the switched resonant branches, it is found that the branches will not generate additional switching losses, nor will they affect the working principle of each module. Compared with the conventional decoupling algorithm of voltage-sharing control, the voltage self-balancing characteristic of the proposed topology avoids the system stability risk caused by insufficient modeling accuracy. In this paper, the voltage control design of the DC transformer is given, and the control scheme for the removal and recovery of the faulty module is given without changing the working state of the resonant branch. The functions and characteristics of the topology are verified by simulation and experiments.