A Control Strategy of the Three-Level Dab-Src with Wide Voltage Range

With the development of the new energy industry, the demand for isolated wide range converters is increasing. The three-level (TL) dual active bridge (DAB) series resonant converter (SRC) is focused on and the time domain model with three control freedom degrees (frequency, phase shift angle and duty cycle) is built and analyzed. Besides, a control strategy is proposed in order to extend the voltage range and the softswitching range. A 1 kW rated-power prototype with 400 V input and $200 ~\mathrm{V}-450 ~\mathrm{V}$ output is built and tested to verify the theoretical analysis results.