Modulation and Realization of a Current-fed Dual Active Bridge DC-DC Converter

With the continuous development of new energy, the demand for energy storage devices is increasing. The current-fed dual active bridge DC-DC converter is an important converter used in these devices. Among many topologies, this article studies the staggered parallel dual active full-bridge converter topology with high-frequency transformer, and conducts a detailed analysis of its working principle and modulation strategy. This paper constructs a three-degree-of-freedom modulation strategy. Duty cycle and phase shift modulation are combined for a wide voltage adjustment range. Duty cycle of low-voltage-side switches, external phase shift angle and internal phase shift angle of high-voltage side are used as degrees of freedom to implement a low-current-ripple and wide-voltage-range modulation strategy. This article analyzes operating modes of the circuit based on this strategy, and calculates boundary conditions of the state quantities and variation ranges of different operating modes. This strategy has been verified on the hardware platform. It can maintain transformer voltage matching when the DC voltage on both sides changes and reduce the current stress of electronic devices.