Sliding mode based feedback linearizing controller for grid connected multiple fuel cells scenario

• More realistic modeling of SOFC is done and different converters design is given.
• A robust FBLSMC scheme is designed for the control of SOFC units.
• Integrated control of multiple DGs is carried out using master–slave scheme.
• Frequency, uncertain load disturbances, load dispatches are considered for study.
• Superiority of developed control architecture to conventional is demonstrated.

The energy demand is growing at a fast rate around the globe. The conventional power generation technologies may not meet the environmental constraints. Hence, a Solid Oxide Fuel Cell based power generation unit is considered as distributed generating source here, in this paper. An integrated operation of two units is done with a master–slave control strategy. Voltage source converters are used to interface nonconventional energy sources with grid, in general. However, these systems are highly nonlinear and coupled systems. Hence conventional PI controller will not give satisfactory performance for changing operating conditions and uncertain load changes. Hence, feedback linearization scheme has been formulated, which uses nonlinear transformation by means of diffeomorphism mapping to convert nonlinear models into linear models. Sliding mode control technique has been incorporated in the feedback linearized control to address the issues of uncertainty and to add robustness to the control algorithm. The developed control algorithm is tested for different dispatches, load uncertainties, decoupling of control variables and finally the variable grid frequency within a small band.