Algeria possesses climatic conditions and natural resources very favorable for exploitation of renewable energy. Hybridization of these energies is a solution for an autonomy and reliability of the power production. The most used is type wind-photovoltaic. For the best quality produced by these systems we used multilevel inverters. A serious constraint in a multilevel inverter is the capacitor voltage-balancing problem. The unbalances of the different DC voltages sources of the five-level neutral point clamping (NPC) voltage source inverter (VSI) constituted the major limitation for the uses of this power converter. The aim of this paper is to give a solution to unbalance problem of the input DC voltages of the five-level NPC VSI used in hybrid renewable energy system application constituted by double fed induction generator (DFIG), where the rotor is driven by wind system maximized in power and piloted by photovoltaic system with fuzzy logic maximum power point tracking (MPPT) connected via five-level NPC VSI. The stator is directly connected to the network. The study shows particularly the problem of the stability of the DC voltages of the inverter and its consequence on the performances of the DFIG with power control. Then, we propose a solution to the problem by employed closed loop regulation using proportional-integrator regulator (PI). We add Clamping Bridge to stabilize the four DC input voltages of the five-level NPC VSI. The results are full of promise to be used to stabilize the input DC voltages of the five-level NPC VSI in this kind of application.
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