Analysis and Design of a Partial-Power Post-Regulator Based DC/DC Converter for Automotive Applications

This paper proposes and analyzes a partial-power (PP) converter for electric vehicle charging applications, where high efficiency over a wide range of battery voltages is required. The proposed converter employs a first dual-output isolation stage and a second dual-input buck post-regulator. In such a post-regulator, only a fraction of the transferred power is processed, whereas the other part of the output power flows directly to the load without any conversion losses. This allows high efficiency even with output voltages that may vary over a wide range. The isolation stage is always operated at resonance, it behaves as a dual-output dc-transformer (DCX), ensuring very high efficiency. The conversion structure, analysis, and design considerations are shown considering a prototype rated 10 kW and interfacing a 800 V dc-link with an output bus in the voltage range 250 V - 500 V, which is common in electric vehicle battery-charging applications.