A high power, current sensorless, bi-directional, 16-phase interleaved, DC-DC converter for hybrid vehicle application

A 16-phase interleaved bidirectional DC/DC converter is presented featuring smaller input/output filters, faster dynamic response and lower device stress for hybrid vehicle applications. This converter is connected between the ultracapacitor (UC) pack and the battery pack in an energy storage system of a hybrid vehicle. Typically, multi-phase interleaved converters require a current control loop in each phase to avoid current imbalance among phases. This increases system cost and control complexity. In order to minimize imbalance currents and remove the current control loop in each phase, the converter is designed to operate in the discontinuous conduction mode (DCM). The high current ripple associated with DCM operation is then alleviated by interleaving. The design, construction and testing of an experimental hardware prototype is presented, with the test results included. Finally, a novel soft switch topology for DCM operation is proposed for future research, to achieve zero-voltage switching (ZVS), or zero-current switching (ZCS) in all transitions.