Three-port Hybrid-type Dual-mode Isolated Resonant DC-DC Converter and its Optimized Modulation Strategy

A three-port hybrid-type dual-mode (HTDM) isolated resonant DC-DC converter for wide voltage range applications is proposed in this paper. The topology is adaptively reconfigured according to the port voltage and accordingly, the distribution of voltage and current stresses is optimized and the overall system efficiency is improved. To simultaneously address the issues of power coupling, zero voltage switching (ZVS) and current stress in three-port DC-DC converters (TPC), a multivariable coordinated optimized modulation strategy is proposed. By the multi-objective modulation synthesis under multiple constraints, the closed-form solution of the six control degrees of freedom, including five phase-shift angles and the switching frequency, is obtained. Both the switching and conduction losses are reduced. A 1.5 kW experimental prototype covering 200-800V is built. The experimental results show that the proposed converter reduces the current stress under low voltage conditions, and the power decoupling, ZVS and resonant current reduction are achieved by the proposed optimized modulation strategy. The effectiveness and feasibility of the proposed converter and modulation strategy are verified.