Sliding mode control of a photovoltaic-wind hybrid system

This paper proposes a hybrid energy system combing solar photovoltaic and wind turbine as a small-scale for stand-alone applications. The proposed system consists of a variable-speed wind generator, wind-side converter, solar array, DC-DC converter and isolating DC load. The power control strategy is to extract the maximum energy from the photovoltaic array and wind turbine under varying climatic conditions. The SMC proposed in this paper, to controlling the output voltage of the DC-DC converter and the out voltage of the AC-DC converter, in order to maintain and stabilize the constant DC-link voltage in climatic and load variations. Furthermore, classical controls PI compared with the SMC. The results show that the SMC technique is more suitable than those classical controls. It improves the transient response and reduces the steady state error of the DC-link voltage because offers a very good way to implement a control action which exploits the inherent variable structure nature of converters. This paper too proposes a control strategy of a maximum power point of a stand-alone PV system using the SMC technique. The efficiency of the proposed control approach is compared with the traditional P&O technique. The MPPT proposed has good performances of the PV system. A simulation model for the hybrid energy system has been developed using MATLAB/Simulink.