Robust Continuous Nonlinear Predictive Controller (CNMPC) via Integral Sliding Mode Control (ISMC) for Grid-Tied PV Inverter

This paper presents robust continuous non linear control for grid tied PV inverter by combining model predictive control (CNMPC) and integral sliding mode control (ISMC). Based on cascaded control structure, combination of CNMPC and ISMC is proposed for both outer and inner control loops. Low pass filter is used to extract the equivalent of the discontinuous switching of ISMC so that the outputs of ISMC and CNMPC are added. Moreover, it is mathematically illustrated that the equivalent of ISMC is actually the same as the magnitude of disturbance. The performance of the proposed controller is verified through series of simulation tests. The combined controller shows robust response for parameter uncertainty and external disturbances such as dc current from PV. It is also shown that the grid current total harmonics distortion(THD) is within the international standards.