Abstract Aiming at the applications of high voltage and wide voltage input, low voltage and high current output, a combined two-stage modular input-series output-parallel DC-DC converter and its voltage sharing control strategy are proposed. The module unit adopts a two-stage topology combining the LLC working in fixed-frequency and open-loop mode and the Buck working in closed-loop mode, which is both efficient and convenient for serial-parallel connection. By constructing the voltage-sharing bus and sampling the input voltage of the moduleindirectly, the signals are respectively superimposed on the feedback voltage and the reference voltage so that the module unit can achieve input voltage sharing by self-regulation while maintaining a good output voltage accuracy. The sampling, control and communication of the module are completed on post-stage.They work independently and simplify the circuit structurewith a good modular features. Combined with the small signal model, the stability of the system is theoretically analyzed and verified by simulation. Finally, a combined ISOP converter consisting of three modular units is built in the lab to verify the strategy.
GuGongshan,ZhengXiangjie,Gao Ming等. Research on Voltage Sharing Control Strategy of a Combined Two-Stage Modular Input-Series Output-Parallel DC-DC Converter[J]. Transactions of China Electrotechnical Society, 2019, 34(15): 3175-3185.
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2019, Vol. 34 
