Solution to the Instability of DC Bus Voltages in Wind Chain Associate to DFIG with MPPT

Abstract

The current trend is moving towards the exploitation of renewable energy especially wind energy. This energy maximized in power (MPPT) is exploited through a system containing a double-fed induction generator (DFIG) driven by the rotor through static converters. For a better quality produced by the chain of wind energy production, we use multilevel inverters, whose several works lifted problems of fluctuation at the levels of the input voltages of the five -level neutral point clamping (NPC) voltage source inverter (VSI). This constituted the major limitation for the uses of this power converter. Our contribution lies in the stabilization of the different input voltages of the inverter using a feedback loop control to regulate the average total DC voltage of the inverter by using proportional integrator regulator (PI) and fuzzy logic controller (FLC). To improve the regulation of the input DC voltages, we introduce a power electronic circuit composed of a transistor in series with a resistor. These transistors are controlled to stabilize the input voltages of the inverter. The results obtained show that the use of the five-level NPC VSI in wind system is full of promise on condition to solve the instability problem of the input voltages.

Keywords

• Wind energy; MPPT; DFIG; five-level NPC; PI regulation; fuzzy logic regulation; clamping bridge