Research On Novel Double-input DC/DC Converter For DC-building Power Supply

As the traditional energy exhausting and environmental deterioration, thedistributed power generation technology is to alleviate the energy crisis and effectivesolutions to improve the environmental pollution. The DC micro-grid integratesvarious types of distributed power sources with the DC bus by the means of the DCdistributed network. It can effectively improve the reliability and controllability ofdistributed power supply, and reduce the impact to the utility power. Especially, onoccasions of the DC source, such as photovoltaic (PV) systems and energy storagesystems, and on other occasions when DC loads account for a relatively largerpercentage among all the loads, such as at the telecommunications data centers, in theaerospace systems, the commercial buildings, and the electric vehicles, DC micro-gridcan harvest higher efficiency. In these occasions, DC micro-grid can greatly improvethe efficiency of energy utilization.In DC building distributed energy power supply field, the multiple-input DC/DCconverter plays an important role in distributed generations connecting, converting,and the coordinating of energy management. Aiming at the problem for reversepolarity of the traditional Buck-Boost converter input and output voltage, a newmultiple-input Buck-Boost converter is proposed. The newly-proposed multiple-inputBuck-Boost converter is conducive to a variety of distributed generations joint powersupply. A double-input Buck-Boost DC/DC converter is taken as an example toanalyze its operating modes, input/output characteristics and power sharing capabilitywere derived. The control strategy is introduced and the wind-solar hybrid powersupply is realized. Secondly, the n-input Buck-Boost converter made up of n newBuck-Boost cells was deduced. Besides, it has the advantages of concise of circuittopology, realization of ascending and descending voltage, the same polarity of inputand output voltage and the power supply of input source alone or simultaneously.Finally, using the MATLAB simulation model and experimental results verify thecorrection of the theoretical analysis and the feasibility of the control strategy.There are many advantages of multiple-input flyback DC/DC converter, such assimple circuit configuration, low cost and low stress of the switches. It has a goodapplication prospect in the low/medium power situation of the DC micro-grids system.With the increase of the input source, the degree of freedom in controlling more flexible,and the switching losses and switching stresses of the power switches are increased.The active clamp soft-switching technology applied to multiple-input flyback converter,and zero-voltage turn on and turn off of the switches are realized. The componentsstresses and losses of the power switches are reduced, the input sources can deliverpower to the load individually or simultaneously. A double-input flyback DC/DCconverter is taken as an example to analyze its soft-switching operating process in detail.The main parameters of the resonant circuit are deduced. Simulation results can verifythe correction of theoretical analysis.