Research And Implementation Of A Bi-directional DC/DC Converter Based On Synchronous Rectification

With the increasing seriousness of environment pollution and the decreasing ofnon-renewable energy, people demand for new clean energy become more and morestrong.As the hub between a new clean energy and energy storage devices,bi-directional DC/DC converter not only can effectively improve the quality of newenergy power generation systems, but also significantly improve the utilizationefficiency of new clean energy. In order to meet the requirements of high efficiency,high power density and low cost. This dissertation designs a bidirectional DC/DCconverter based on synchronous rectification. The main contents are as follows:The overall scheme of bidirectional DC/DC converter was proposed, Theworking principle of traditional rectification bidirectional DC/DC converter andsynchronous rectification bidirectional DC/DC converter were elaborated. Calculatedthe parameters of the components and selected suitable MOSFET for power switchdevice. The efficiency of the converter has been initially estimated by analyzing theloss of the circuit.The dynamic characteristics of the converter was analyzed, the small-signalmodel of converter working at different modes was established independently, largesignal transient characteristics of the converter were analyzed qualitatively, soft-startcontrol strategy based on the dead time was designed.The corresponding hardware circuits, including the main controller and the maincircuits, were designed according to the demands of the converter. The maincontroller includes the sampling unit, protection unit, communication unit and themicroprocessor unit. The main circuits include the main circuit layout and design ofthe radiator. Meanwhile, MOSFET drive circuit design was analyzed in detail.The overall performance of the converter has been tested, including voltageripple, current ripple and efficiency in different working modes. Compared theexperimental results and performance indicators, the bidirectional DC/DC converterbased on synchronous rectification can achieve higher efficiency, higher powerdensity and lower ripple.