Fuel cell and ultra-capacitor based hybrid energy control using IDA-PBC methodology

The paper presents passivity based control strategy for hybrid energy management system comprising of fuel cell and ultra capacitors. Industrial applications like electrical vehicles and certain microgrid combinations are using fuel cell as a clean energy alternative for the requirement of DC supply. But due to its slow dynamics it needs to be often combined with auxiliary storage systems like battery, super capacitors or ultra capacitors. We consider hybrid combination of fuel cell with ultra capacitors because it supports instantaneous charging and discharging characteristics with increased life time. The main contribution of this paper is to synthesize a non-linear control law based on interconnection damping assignment-passivity based control (IDA-PBC) with a desired energy function combining exponential and quadratic form. It was shown that the derived energy function satisfies conditions for candidate Lyapunov function and hence thereby satisfies stability criterion. Mathematical model of the system is obtained by the state space averaging approach. Simulations are performed on LabVIEW environment to validate the results.