Comparison and Analysis of Control Strategies to Achieve High Efficiency for Cascaded Boost Converter in Fuel Cell Electric Vehicle

In fuel cell electric vehicles (FCEVs), the fuel cell DC–DC converter (FDC) boosts the voltage of the FC stack to the DC-link voltage required by the inverter. To reduce the volume of the FC source by lowering the FC stack voltage, a topology that can achieve higher voltage gain than conventional boost converter is required. Therefore, a cascaded boost converter (CBC) which has a large voltage gain can be adopted. Given that the CBC can apply various control method, a quantitative analysis under each control method is required to determine high-efficiency operation. Therefore, this paper analyzes and compares three control methods for CBC to determine the optimal control strategies considering FC voltage and current. A 55kW multi–phase interleaved CBC is designed considering volume, efficiency, and temperature of power devices. Furthermore, theoretical loss and efficiency analyses are performed and validate the proposed control strategy’s effectiveness through experiments results.