The input voltage sharing control strategy for input-series and output-parallel converter under extreme conditions

Input-series and output-parallel (ISOP) converter is very suitable for high input voltage and high power applications. Input voltage sharing (IVS) and output current sharing (OCS) of the modules among the ISOP converter should be ensured. This paper reveals the failure mechanism of IVS of the ISOP converter system under extreme load conditions. Based on the existed input voltage sharing control strategy, this paper proposes two methods, including changing the weighted averages of input voltage sharing loops and adding an input voltage sharing auxiliary circuit, to achieve IVS of the modules under the extreme load conditions. The experimental results are presented to verify the effectiveness of the proposed control strategies and auxiliary circuit.