High Efficiency Bidirectional DC-DC Converter with Matrix Transformer for Heavy Duty Hybrid Electric Vehicles

A DC-DC converter is an essential component in Hybrid Electric Vehicle (HEV) to achieve power transfer from High Voltage bus (HV) to Low Voltage bus (LV) and vice-versa. Very high current on the LV side of the high power DC-DC converter in a heavy-duty hybrid vehicle makes its design extremely challenging. Dual Active Bridge with an integrated matrix planar transformer is considered due to its advantages over other existing topologies, such as the ability to handle very high current on the LV side, bi-directional power flow, high power density, zero voltage switching capability, and high modularity. An integrated planar Matrix transformer is chosen for galvanic isolation, as it helps in handling very high current on the LV side efficiently. Multi-Objective Design Optimization, with low converter loss and low converter volume as its objectives, is used as a basis of parameters and components design. Current-mode control is implemented to achieve a fast response and avoid transformer saturation due to the DC flux injection during the transients. The design algorithm and control scheme has been experimentally verified.