Pulse Generation Control Strategy for Smooth Supercapacitor Charging from a Fuel Cell

Electricity generated from fossil fuels emits significantly higher levels of toxic gases compared to renewable energy sources. The adoption of hybrid energy systems is essential to support the transition from fossil fuel-based power generation. This paper presents a strategy for charging a supercapacitor (SC) using a fuel cell (FC). The FC exhibits a slow response to load variations, due to its large time constant. Whereas the SC is suitable for handling rapid power fluctuations. To facilitate energy transfer between these two components with different dynamic characteristics, a DC-DC converter is utilized. The dual active bridge (DAB) converter is selected for its high voltage gain, soft-switching characteristics, and galvanic isolation between the primary and secondary side. A pulse generation control method is proposed to regulate the switching pulses of the converter, acting as an effective interface between the FC and SC. This control strategy enables a gradual charging of the SC, preventing abrupt changes in current and voltage that negatively impacts the FC. The effectiveness of the proposed pulse generation control is validated through simulations carried out in the MATLAB/Simulink environment.