Research On Multiple-Input Voltage-Fed Push-Pull Converter With Single Primary Winding

Energy crisis and environmental pollution are common problems facing humanity, and newenergy power generation is an effective way to solve these problems. Single new energy powergeneration is vulnerable to weather and climate, leading to some disadvantages such as intermittenceand labialization, so the hybrid renewable energy power system should be adopted. Conventionalhybrid renewable energy power system is complex and expensive, and using a single multiple-inputconverter (MIC) to replace those separated dc-dc converters can effectively reduce the complexity andcost. This paper is dedicated to isolated MIC circuit topologies and control strategies.After extensive research, some scholars decomposed MIC into pulsating source cell (PSC) andoutput filter, and then proposed a series of PSC systematically, including pulsating voltage sourcecells (PVSCs) and pulsating current source cells (PCSCs); meanwhile, each category can be dividedinto isolated and non-isolated types. On the basis of analysing the converter structure and thecombination principles of PSC, this dissertation decomposes converter into input source and motherconverter. Replacing the input source of single-input isolated converter by non-isolated PSCsconnecting in series or parallel, the isolated single-primary-winding MIC is proposed.In accordance with the combination principle, making PSCs connecting in series or parallelcascade the corresponding filter, isolated and non-isolated MIC will be generated. But those isolatedMICs’ structure is relatively complex. Push-pull converter has simple structure and can be controlledneatly, so it’s widely used in small and medium-power applications. Making use of the push-pullconverter, we derive a family of voltage-source type double-input push-pull converter. Simultaneously,the detailed discussion of the voltage-source type push-pull MIC control strategy is given, and thecontrast between single-primary-winding MIC and traditional MIC is elaborated.Since the simplest type of PVSC is Buck, they are chosen as an example to connect in seriesforming single-primary-winding voltage-fed multiple-input push-pull converter. In this dissertation,operational modals are analyzed; the input and output relationship is derived as well as the voltageand current stress of switches; issue of transformer magnetic bias and countermeasure are illustrated;the impact of inductor current ripple is also discussed on different control methods.In order to achieve full utilization of renewable energy, we should ensure the maximum poweroutput of new energy; Meanwhile, in order to achieve reliable operation of the load, we should ensure output stable. By coordinating the work way of switches in MIC, energy management strategy abovecould be achieved. This paper presents a detailed control program, analyses three models of system,and discusses specific measures to achieve control program.Finally, in view of the performance indicators, design of main circuit and control circuit arecompleted, and simulation circuit is build. In addition, a400W prototype is made in laboratory. Afteraccomplishing the simulation and experiment commissioning, the results are given to verify thecorrectness of theoretical analysis.