Research On Bidirectional Multiple-input Current-fed Full-bridge Converter With Single Primary Winding

The widespread use of renewable energy can mitigate the energy crisis and reduce theenvironmental pollution. Most renewable energyare intermittent and random not possible at all timesbecause they are strongly dependent on the climates and weather. But they are mutuallycomplementary in the sense that they can be utilized simultaneously to maintain continuous deliveryof power to the load, which can be named as hybrid renewable power system. In such systems, the useof a multiple-input dc/dc converter (MIC) leads to simpler circuit and lower cost, compared to theconventional use of several single-input converters. This paper focuses on the topologies ofbidirectional current-fed full-Bridge MICs with Single Primary Winding(SPW).In the past, the topologies of bidirectional MICs can be roughly divided into three types, that is,the wire coupling type, the magnetic coupling type and the integrated type. The topology ofbidirectional MIC with wire coupled is simple and easy to control, so it can be applicated flexibility,but according to the lack of electrical isolation, it can not be used in theoccasion that has bigdifference between the input and output voltage. Bidirectional MIC with magnetic coupled realizesthe power conversion, which is electrical isolation, through magnetic coupling. So it can achieve theinterconnection between multiple different voltage levels of power with selecting the transformerturns ratio, leading to a wider range of applications. But Primary winding and the required powerdevices are increased with more input sources. It will lead to control difficulties and costsincrease.The integrated type bidirectional MIC combines the advantages of the first two bidirectionalMIC,so it can be used in a broader range.This paper proposed a family ofsingle primary winding bidirectional current-fed full-bridgeMICs by using the non-isolated bidirectional pulsing current sources in parallel to replaces the inputsources of the single-input bidirectional full-bridge converter. It belongs to the integrated typebidirectional MIC. Compared with the wire coupling type bidirectional MIC, it can be used in theoccasion that has a higher voltage level, according to the electrical isolation. Compared with themagnetic coupling type bidirectional MIC, it has a simple structure and more flexible control, and itonly require a primary winding, reduce the leakage inductance. This converter can achieve the goalthat all the power sources can supply power to the load independently or simultaneously, and energycan be fed from the load. This converter uses the structure of current source, the input current iscontinuous and only has a small pulsating, which can extend the life of the photovoltaic cells, fuel cells, etc effectively.A novel boost-type bidirectional double-input current-fed full-bridge converter with singleprimary winding is chosen as an example to illustrate its operating principle and analyze its workmodein detail. At last, based onparameters design of the converter, an1000W prototype has been builtand tested in the lab. The experimental results verifythe theoretical analysis.