A variable step size fuzzy MPPT controller improving energy conversion of variable speed DFIG wind turbine

Abstract

With the world’s fastest growing rate and the prominent part of installed renewable energy sources, it is clear that wind is now a mainstream source of energy supply that will play a leading role in the proclaimed fight against climate change. But becoming mainstream means also assuming new responsibilities, including ensuring the reliable and cost-effective functioning of the overall energy system. In this context, this paper deals with the problem of extracting the wind turbine maximum power, power that depends on the random nature of wind speed and the nonlinear characteristic P = f(w) making it more difficult to extract. For this task, we propose a variable step size fuzzy maximum power point tracking controller. The proposed controller is tested on wind turbine based on a doubly-fed induction generator controlled by a field-oriented control implemented using Matlab/Simulink environment. Simulation results are presented showing a net improvement using the proposed MPPT to converge toward the optimal point with good accuracy and low oscillations around the MPP point achieving better performances.

Keywords

• dfig
• fuzzy logic
• mppt
• perturbe & observe
• tip speed ratio
• wind turbine