Research on voltage sharing for input-series-output-series phase-shift full-bridge converters with common-duty-ratio

Aiming at the application requirement of high-input-high-output voltage, a novel solution on the base of input-series-output-series (ISOS) connected converter was proposed in the paper. The ISOS converter consists of two zero-voltage-zero-current-switched full bridge (ZVZCS-FB) converters, which are using the common-duty-ratio and share the same controller. The characteristics of the voltage sharing is analyzed in detail and verified by the experiments. The small-signal analysis of the topology and the design of the controller are also discussed in detail in the paper. The research results indicate the relationship between the effective duty ratio and the efficiency of each module, when the input voltage of the two modules is stable; and there is no need to take any measurements to realize the voltage sharing of the two modules, when the efficiency of the two modules are equal. The proposed solution has good value for high input voltage, high output voltage and high power applications.