双向隔离型 DC-DC 变换器软开关调制策略分析

With the vigorous development of electric vehicles and energy storage industries, the power electronics technology has been applied on an increasing scale. In these applications, power electronic converters not only require wide voltage gain to adapt to different scenarios, but also require a high conversion efficiency to reduce volume. Therefore, bidirectional isolated DC-DC converters with soft switching have been widely studied. On the basis, the principle of isolated DC-DC converters was analyzed, and the conversion efficiency under wide voltage gain was improved by reducing the reactive power current and implementing soft switching. First, a mathematical model was established through fundamental wave analysis to obtain the conditions for controlling the phase shift angle on the primary side, secondary side, and both the primary and secondary sides to achieve reactive power current elimination. Then, the conditions for achieving soft switching of switching devices on the primary and secondary sides were analyzed, and the dead time was designed to adjust the phase shift angle between the primary and secondary sides, so that a modulation strategy for achieving ZVS with minimal reactive power current was obtained. Finally, a 9.6 kW experimental prototype was designed to verify the feasibility of the proposed modulation strategy.