DC-DC Converter In Electronic Power Transformer

Electronic power transformer (EPT) can solve many new problems in future electricpower system, will be widely applied. The researches of EPT have important theoreticaland practical significance. DC-DC converter is an important part in EPT, as it has effect ofpower transmission, voltage switch and electric insulation. Therefore, it’s necessary to takea special research of DC-DC converter in EPT. This paper mainly studies the circuit ofDC-DC converter in EPT.Considering the high power and high voltage of EPT, this paper proposes the fullbridge converter with the uncontrolled rectifier, including a high-frequency transformer,two full-bridges and output filter. The DC-DC converter in this paper is controlled by PWMalgorithm. According to the current through transformer is continuous or not, three differentoperating modes can be distinguished: continuous mode, discontinuous mode, and bordermode. This paper studies the impact of transformer’s leakage inductance and the value ofoutput inductor on the transformer’s input current and transfer power.Base on the technical guideline of EPT, this paper designs the circuit and calculatesprimary parameters of DC-DC converter, including the design of high-frequencytransformer and output filter, the selection of switch equipments and input capacitance.Then, we develop a DC-DC converter to apply in EPT, and test its work performance byexperiment.To increase transfer power and decrease size of DC-DC converter, this paper studiesinput series output parallel (ISOP) DC-DC converter, and analysis controlled by chiasmusalgorithm, the ability of restrain input current ripple and output current ripple.In addition, this paper calculates power loss of switch implement in DC-DC converter,and compare the power lose switch implement in ISOP DC-DC converter withsingle-module DC-DC converter.