A Wide Range Unidirectional Isolated DC-DC Converter for Fuel Cell Electric Vehicles
Tianqi Hong, Zhi Geng, Kedao Qi, Xiaonan Zhao, Joseph Ambrosio, Dazhong Gu
Abstract
A low-cost unidirectional dc/dc converter with galvanic isolation for fuel cell electric vehicles is presented in this article. To satisfy the requirements of the fuel cell stack and powertrain system of heavy-duty vehicles, three operation modes: boost, buck-boost, and buck, are proposed. To achieve ZVS operation for low voltage side switching devices, a novel platform current control mechanism is introduced. With the help of the platform current controller, the zero-voltage-switching operation is independent of the input/output voltage ratio. Meanwhile, the near zero-current-switching can be achieved for low voltage side switches under boost mode. The steady-state analyses and small-signal models for both input and platform currents under boost mode are provided. The prototype unit is built, and the corresponding experiments are presented.