Fuzzy logic and passivity based control applied to hybrid DC power source using fuel cell and battery

Fuel cell systems offer clean and efficient energy production and are currently under intensive development by several manufacturers for both stationary and mobile applications. Therefore, their slow dynamics and difficulty to respond to the abrupt changes of load leads to prefer the association of a FC with one or more power sources of high dynamics, such as supercapacitors or batteries. In this paper, a hybrid DC power sources system using FC as a main source, a DC link and battery as an auxiliary power source is studied. The main purpose of this work is the control of the hybrid DC source by Passivity-Based Control (PBC) where the equilibrium points are computed as function of the desired battery current. PBC is a very powerful nonlinear technique dealing with important system information like the system´s total energy. The second aim is to determine the desired battery current by a Fuzzy Logic Control (FLC) as function of battery state of charge SoC and the hydrogen quantity QH₂ in order to ensure the desired behaviour of the system. Stability proof and simulation results are given.