Dual Functional Power Management System for an Energy Storage in Light Fuel-Cell Hybrid Electric Vehicles

This paper presents a new dual functional control system for an energy storage in a light fuel-cell electric vehicle such as a small motor cycle and an electric cart. The proposed control system manages charging and discharging of an energy storage and regulate two bus voltages at the same time to minimize the number of circuit elements in the system. Since a fuel-cell voltage varies based on the load, a boost converter needs to be employed in the proposed system to provide a 48V DC power to a traction inverter for this light vehicle application. An additional voltage bus which can be higher or lower than the input fuel cell voltage is added for other electric loads. The new dual functional controller is employed for this system to control two different output voltages and manage a battery at the same time. Through the effort of the dual functional control system, one switching element and one inductor can be removed while keeping the same functionality. The proposed dual-functional control strategy and the converter structure are explained in detail first. Then, the feasibility of the converter is verified by experiments.