A GaN Switched Tank Converter with Partial Power Voltage Regulation for Electric Vehicle Applications

A new Switched Tank Converter (STC) with Partial Power Voltage Regulation (PPVR) is introduced for electric vehicle applications. It offers a flexibly adjustable conversion ratio for a wide-range battery voltage. The unregulated stage is modularized with resonant switched capacitor converters. All device voltage stresses are equal to the input voltage. The efficient unregulated stage processes the bulk of system power and the less efficient regulated stage processes a small amount of power. Thus, high overall efficiency can be achieved. A new index called Semiconductor Loss Index (SLI) is defined as a function of semiconductor die area to evaluate different power topologies. It is helpful to analyze the impact of each switch die area, different operated output power, switching frequency, and conversion ratio on the total device power loss. With the same total semiconductor die area, the proposed converter can achieve less than 1/3 device total power loss compared with boost converter. A 4-kW 1200V output converter prototype with 200V~400V input voltage range is developed, which combines a 6 times conversion ratio STC with a PPVR buck converter. The overall full-load efficiency of designed 4-kW converter can reach to 97.71%. Simulation, prototype and experiment results are presented to verify the validity of the proposed converter.