Nonlinear sliding mode control design for a multimachine system composed by four marine turbine system

In this paper, we deal the control problem for marine turbine systems in multimachine configuration. For this, we are modelling four interconnected marine turbine system and connected to an infinite bus by taking into account the multimachine interactions and the marine current dynamics. This multimachine system modelling is made through a transmittance matrix which uses the voltages and currents at each nodes of interconnection network. A decentralized sliding mode control is designed by using this multimachine model with taking into account the marine current constraints and multimachine interactions. Our proposed control law is applied on our multimachine marine turbine system in simulation under Matlab/Simulink environment with mechanical and electrical perturbations. The electrical perturbation is a short circuit of 200ms duration and the mechanical perturbation is the mechanical power drop of 50% of its value. The obtained simulation results prove that the proposed decentralized sliding mode control is able to well regulate our multimachine marine turbine system and preserves its performances despite the hydrodynamic perturbations and multimachine interactions. These results are compared to obtained results by the classical AVR-PSS (Automatic Voltage Regulator, Power Systems Stabilizer). The robustness test reveals that the proposed control law is better than AVR-PSS in precision terms and oscillation damping after perturbations.