Research On Non-isolated Three-port Converter With High-gain Based On Switched-capacitor

The three-port converter applied to renewable hybrid power system can be divided into a UTPC(Unidirectional Three-Port Converter)or a BTPC(Bidirectional Three-Port Converter)according to the type of the two input sources.In order to meet the needs of the background and improve the performance of the converter,several novel three-port converter topologies based on the advantages of the non-isolated UTPC/BTPC basic cells and switched-capacitor technology are presented.When both the two inputs are renewable sources,three kinds of UTPC with high gain for individual supplying power based on switched-capacitor are obtained when switched-capacitor is added to different branches of the non-isolated UTPC unit for individual supplying power.After comprehensive analysis,the first topology is identified as the better one and the first study object,whose operation principle and charge-discharge performance of switched-capacitor are analyzed in detail.Extended topology and energy management strategy are also introduced.Simulation and experiment results verify that the proposed topology the has better performance.Nevertheless.time-sharing power supply minimizes energy utilization and switched-capacitor,' peak charging current affects converter efficiency.Taking the the non-isolated UTPC unit for simultaneous supplying power as the carrier,after adding the switching unit between two input sources which is contained in the non-isolated UTPC unit for individual supplying power and the switched-capacitor connected in series on the better branch road,a UTPC with high gain for simultaneous supplying power based on switched-capacitor is obtained,which retains the advantages and improves disadvantages of the first study object,and is identified as the second study object.In addition,it has the advantages of low input-current ripple and automatic average distribution of inductance current under certain conditions.The working principle,voltage and current stress of power device and energy management strategy are analyzed in detail,and are verified by simulation and experiment.The boost capacity of a single switched-capacitor is limited.Four kinds of switched-capacitor cells are presented,which are applied to the second study object and eight kinds of derived structures are obtained according to the parity of the number of capacitors,identified as the third study object The charge-discharge characteristics of topologies are analyzed and those voltage gain,capacitor voltage and power loss are compared.Finally,the correctness of the theoretical analysis is verified by simulation and experiment.In view of the situation that the input source is a combination of renewable source and energy storage unit,the second study object is integrated with the non-isolated BTPC unit,and a BTPC with high gain for simultaneous supplying power based on switched-capacitor is proposed,and it is the forth study object,where switched-capacitor cells are also adaptable.The basic characteristics and energy management scheme are analyzed,and the feasibility of the converter and the effectiveness of the energy management scheme have been proved by simulation and experiment.