Research On DC-DC Converter Based On Half-bridge Topology Circuit

The DC-DC converter is a kind of power electronic device.It can convert the DC power into the DC voltage which is needed by the load.As the main circuit of energy conversion widely used in the field such as new energy power generation system and aviation power supply system,its importance is self-evident.The dissertation does some research about DC-DC converter based on half-bridge circuit,one is the triple modular cascaded buck-boost converter,and the other is the three-port buck-boost converter,after summarizing the current research status of two-port and three-port DC-DC converter.The triple modular can optimize the operating frequency and filter parameters of the converter based on the output voltage and current ripple reduction.The three-port converter can realize centralized control of the power supply,energy storage and load unit,so as to ensure the stable power supply when used in the new energy power generation system.First,the dissertation chose the half-bridge buck-boost converter as the topology unit,analyzed its working principle and characteristics,and studied the cascade buck-boost converter based on it.The working principle and different kind of control strategy are analyzed,including single mode,two modes and three modes.These analyses provide the theoretical basis for the study of triple modular and three-port converter.On this foundation,according to the idea of increasing the equivalent operating frequency of the converter in the form of multi-phase,a triple modular cascaded buck-boost converter is designed.The triple modular converter consists of six half-bridge topology unit,and its operating frequency is increased to three times compared with the original without changing the single switch frequency,thus greatly reduce the ripple of output voltage and current.What's more,the converter can work in three modes:buck,buck-boost and boost,and it's suitable for wide voltage range applications.The dissertation analyzed the working principle and control strategy of the triple modular converter,designed the parameters of the prototype and carried out the experimental verification through the prototype platform.At the same time,a non-isolated three-port buck-boost converter can be formed with three half-bridge topology unit through further research on the half-bridge buck-boost converter.In this dissertation,the working principle of this new three-port converter is analyzed,and a feasible control strategy is proposed to enable the converter operating in three modes:single input single output,single input dual output and dual input single output.The dissertation designed the experimental platform,and the correctness of theoretical analysis and control strategy is verified by experiments.