Performance comparison for grid connected photovoltaic system using sliding mode control

Three sliding mode controllers are designed for the control of a photo-voltaic system connected to grid on the nonlinear behavior of the dc-link capacitor and inverter switching input signals. In this proposed system, a nonlinear state space model is used after abc-dq reference frame transformation to design sliding mode control inputs to ensure the maximum power point extraction from the photo-voltaic system and unity power factor in the grid with different sliding manifolds. The performance of three sliding mode controller is compared and it is concluded that the controller based on the power balanced perform better compared to separate current and voltage tracking. Performance of these controller under nominal conditions, parameter variations and load disturbances is validated by the numerical simulation.