The present work deals with a nonlinear control strategy for the purpose of photovoltaic (PV) systems integration into the power system through cascaded Z-source H-bridge inverters. The topology of the proposed system which is able to obtain a 5-level voltage is discussed. To facilitate a systematic voltage control, an exact nonlinear model of the proposed system is presented. A nonlinear voltage regulator, based on exact input-output feedback linearization scheme, is designed to maintain the terminal voltage of the PV inverter at the point of common coupling. Moreover, to harvest the maximum power from the PV arrays, a nonlinear controller for a dc-dc converter which is in conjunction with the maximum power point tracker (MPPT) is designed. The performance of the proposed Z-source multilevel inverter is evaluated numerically in the MATLAB/Simulink environment. The simulation results validate the performance of the proposed model-based controller in both steady-state and transient conditions, since the nonlinearity of the system is taken into consideration.
['Hamed Taheri', 'S. Taheri']
Modeling and nonlinear control of multilevel inverter for photovoltaic application