Synthesis of two-inductor DC-DC converters

A synthesis principle for two-inductor DC-DC converters with ripple free input/output current is summarized by the study of existing ripple free converter topologies. The LCL structure is found to be very important for ripple free converters. Several variations of LCL cells are derived. It is found that all existing ripple free converters are derivations of the LCL converter cells. In addition, several modified topologies with ripple free input/output current are developed and two modified converter topologies with only two active switches can operate in four-quadrant. Two-quadrant operation may also be achieved by using one active switch and one passive switch.