Evaluation of the Maximum Power Point Tracking performance in small wind turbines

Abstract

In the scope of a further increase in the production of renewable energy, grid-connected small wind turbines offer a promising new technology. To ensure a market breakthrough of small wind turbines, the cost effectiveness must be maximized. Therefore, the aerodynamic efficiency or power coefficient of the turbine blades is an important factor. This power coefficient is determined by the Tip Speed Ratio (TSR), which characterizes the air flow around the blade. The control of the converter must regulate the TSR of the turbine at the most optimal value to maximize the power coefficient. This is done by the Maximum Power Point Tracking (MPPT) algorithm. In this paper, measurement data of three commercial wind turbines is used to evaluate the MPPT performance. The real TSR will be calculated from the measurements and compared to the optimal value for each wind speed. This allows to investigate whether the MPPT performs adequately. From the difference between the real TSR and the optimal TSR, an estimation will be made of the loss of energy yield caused by the possible ineffective operation of the MPPT algorithm. This paper shows and estimates the room for improvement in the MPPT of small wind turbines.