Integrated Phase-Shift Modulation Scheme with Wide Voltage Range Adaptability for Modular Multilevel Resonant DC-DC Converter

This paper introduces and develops an integrated phase shift modulation scheme with wide voltage range adaptability for modular multilevel resonant DC-DC converter (MMDC), which offers a new control degree of freedom for output voltage regulation under wide voltage range operation. By solving state space equation of each resonant state, an analytical model of the MMDC considering the phase shift angle is deduced to analyze the dc gain characteristic. The multi-degree of freedom coordinated control method combining the number of switching sub-modules and the integrated phase shift angle is presented. Finally, simulations on the MMDC that convert 9~14 kV input to 375 V output are exhibited to explain the feasibility of the presented modulation scheme and control strategy. Experimental results of the prototype are also displayed to demonstrate the feasibility. These results suggest integrated phase shift modulation scheme with wide voltage range adaptability.