Research on Structure of the Novel DC Charging Pile Based on Soft Switch Technology

With the development of industry and the goal of decarburation, the proportion of new energy vehicles in the market is getting higher and higher, and the demand for DC charging piles is increasing. Therefore, it is necessary to design a perfect charging pile structure. In this paper, a novel DC charging pile structure based on soft switching technology is proposed, which consists of a power factor correction (PFC) part connected to the power grid and a post-stage ZVS soft switching DC/DC converter. The front PFC uses a three-phase, three-wire VIENNA rectifier. Each power bridge arm consists of two fast diodes and a power switch where current flows in both directions. The rear ZVS soft switch DC/DC converter is composed of three-level half-bridge DC/AC inverter unit, isolation transformer, AC/DC full bridge rectifier unit, output filter unit and output load. In this paper, based on the soft switch technology of new type dc charging pile structure of resonant inductance and resonant capacitance between the resonance, and the three level structure of half bridge converter adopts the phase shifting control method, realized the zero voltage soft switching, small switch loss, high system efficiency and switch tube the characteristics of low voltage, at the same time, The combination with the three-phase three-wire VIENNA rectifier makes the structure more widely used.