Dynamic Analysis of Three-Port DC/DC Converter for Space Applications

This paper presents the control structure for a novel three-port converter topology. This topology has the advantage of low switch count, high power density, high efficiency, so it is a valuable choice for space applications. The three port converter for space application interfaces one solar panel input port, one bi-directional battery port and an isolated output port. Lithium-Ion battery charge control simulation is implemented. Maximum Power Point Tracking (MPPT) is adopted to maximize the solar energy input. Two of the three ports can be simultaneously regulated. However, the two control loops have interactions with each other due to the integrated power trains of the three ports. Therefore, implementing the closed loop control requires careful analysis of their dynamic behaviors. In this paper, the dynamic behavior of the converter during different operational modes is fully characterized and studied. Small signal models are derived based on state space equations, and experimental results verify the converter control structure.