Decoupling Current Sharing Control for Paralleled DC-DC Converter in Aerospace Application

A decoupling current sharing control (DCSC) is proposed in this paper to improve the current sharing performance of a paralleled DC-DC converter in aerospace application. For paralleled DC-DC converters, there inevitably exists parameter mismatches due to limited manufacturing tolerances, which can cause strong system coupling and deteriorate current sharing performance. To cope with this issue, the mathematical model of a two-paralleled buck DC-DC converter (TPBDC) is proposed, while the corresponding system coupling is analyzed. The DCSC is then proposed, which consists of the input transformation (IT) and the state feedback (SF). To further enhance the decoupling performance, a state observer (SO) based on output current is proposed to estimate the inductor current. The resulting control strategy can distribute the current of each paralleled module directly and achieve excellent current sharing performance by using precise decoupling method, which is also verified by the simulations. The novelty of this research is to explore a decoupling control method to optimize the current sharing performance of paralleled DC-DC converters.