Circulating and Leakage Power Flow Elimination Technique between Source Ports in Triple Active Bridge Topology

This paper presents a technique to eliminate circulating and leakage power flow between source ports of Triple Active Bridge (TAB) isolated bidirectional dc-dc converter. When two different dc sources are used to supply load power simultaneously in TAB topology, interconnecting winding of transformer provides a leakage inductance path for the flow of circulating and leakage current. It happens due to unmatched voltage magnitude and phase difference of ac voltages impressed across winding. The ac voltages are produced by full bridge of corresponding dc source ports. This circulating and leakage current results in increased conduction and copper losses in switches and transformer respectively. High value of this circulating and leakage current can even damage the transformer core as well as Windings. Therefore, a blocking capacitor is employed to create infinite impedance between source ports and thus it open circuit current path to block circulating and leakage power. With proposed technique, the different source ports of TAB can operate with Wider range of phase delays and voltage magnitudes with negligible circulating and leakage power. Simulation results employing this technique has been shown which verify the theoretical concept. MATLAB/Simulink platform has been used for simulation.