Bi-directional Dual-bridge Series Resonant Phase-shift DC/DC Converter And Combination Module Research On

This paper explained an AC/DC Hybrid Microgrids, including high-voltage ACpower grid, high voltage DC bus, several DC distribution systems. The several DCdistributed generation systems are connected to a high voltage DC bus, the energy of eachmodule is allocated by the high voltage DC bus. Each module can absorb energy from thehigh voltage DC bus and transfer energy to the high voltage DC bus. This advantageproposed bidirectional DC/DC converter applications background of this paper.In order to achieve each module which can transfer energy to each other, it isnecessary to achieve the two-way flow of energy of the high and low voltage DC bus.Thanks to the large voltage difference between the high and low voltage DC bus, thispaper explained a multi-module input parallel output series system, which makes thedesign of the individual modules easier. This paper took two module input parallel outputseries as an example, the output voltage sharing to ensure that the input current sharing. Asingle module topology using isolation dual-bridge series resonant converter based on thestudy of existing bidirectional DC/DC converter. The resonant converter topologies takeadvantages of series resonant converter that they can achieve ZVS soft switching. The useof the phase shift method to control the size and direction of energy transfer, simplifies thecontrol method.Application of fundamental analysis simplifies the converter to AC equivalent circuitthen deduce the resonant current, the resonant capacitor voltage and energy transferexpression,which laid a theoretical foundation for the following parameter optimizationancirculation analysis. Parameter optimization has two goals. When the transfer energy isconstant, the peak of resonant current and resonant capacitor voltage should be minimized.When the energy transfer is changes, the resonant current peak value and the output powerkeep a linear relationship. The goal of circulation analysis is try to reduce the reactivepower both of input side and the output side, to improve the efficiency of the converter.Software is used to simulate the close-loop of single module and dual module inputparallel output series system. The double module closed loop simulation achieves softswitching and input current sharing output voltage sharing, which meet the designrequirements.Finally, according to the method of parameter optimization,we to designed experimental parameters, and built experimental platform. The experimental takes digitalcontrol method. The programs were written to complete positive and negative transferenergy in closed-loop experiments. Switching the input side of the average current throughseria communication, we achieved good experimental dynamic response. Theexperimental results show that the phase shift control method can achieve energy forwardand reverse flow, providing a new method for bi-directional DC/DC converter research.