Research Of Dual Series Resonant Bidirectional Three-port DC/DC Converter

With the growing concern of energy crisis and environmental problems, peoplebecome more aware of the potential of renewable energy source. As a new type ofpower electronic conversion device, multi-port DC/DC converter can achieve theeffective integration of new energies and energy storage elements, manage differentenergy source centralizedly, improve the converter power density and reliability ofpower supply as well as the transient response speed effectively, has a good prospectof application in renewable energy source like photovoltaic cells or fuel cell powersupply system, gradually widely used in the hybrid power system, uninterruptiblepower supply systems as well as commercial and residential buildings.In this paper, a three-port converter with three active full bridges, twoseries-resonant tanks, and a three-winding transformer is analyzed. At first,steady-state analysis of the converter is presented to determine the power flowequations, tank currents, and output voltage. It then focused on the influence of theoutput-side winding leakage inductance, the relationship between the frequency ratioand the power flow of the two input ports is discussed. By choosing appropriatefrequency ratio, the coupling relation between the two input ports can be weakened, sothat the two input ports can be controlled separately. The influence of the phase shiftangle to reactive power and resonant peak current is also considered. The convertercan achieve the maximum range of ZVS for all ports by choosing proper circuitparameters. A control strategy is implemented to regulate the load-side port voltageand source-side port current. Design parameters for the three-port converter andexperimental results of a laboratory prototype are presented.After simulating the converter, the control system is designed using DSP andCPLD. A prototype has been built in the lab, and the experimental results verify thecorrectness and feasibility of the theory.