Passivity Based Control of Complex Switched Mode FC-UC Hybrid Structure with BM Modeling

Fuel cells are emerging as a clean and non-pollutant alternative for the applications involving stationary and mobile energy demand. They are generally used with hybrid combinations when load behavior is not steady, as the operating life of the fuel cell is affected due to the transients. Generally battery or ultracapacitors are used along with Fuel Cell source to respond to such load transients. This paper presents passivity based frame work for modeling and control of fuel cell-ultracapacitor based hybrid energy system. Brayton Moser (BM) formulation has been used the modeling of the resulting hybrid dynamics. Mixed potential functions are then derived for passivity based control strategy. The choice of this controller is governed by the inherent nonlinear dynamics of the system. Simulations are performed in MATLAB/SIMULINK to validate the proposed control laws.