Experimental analysis of impact of maximum power point tracking methods on energy efficiency for small-scale wind energy conversion system
Résumé
The power control of small-scale wind energy conversion system is usually limited by the sluggish mechanical dynamic. Aiming at highlighting this phenomenon, this article introduces a small-scale wind energy conversion system using the permanent magnet synchronous machine as generator to validate different combinations of control strategy resulting from four different maximum power point tracking (MPPT) methods with hysteresis control: one indirect MPPT method based on a look-up table and three direct methods based on perturb and observe relationship. Following two ideal wind speed profiles, a real rapid wind speed profile and using a test bench emulating a small-scale wind turbine, the MPPT methods are compared and analysed based on experimental results. The indirect method operates with the best MPPT performances for all three wind speed profiles while requiring accurate knowledge of the controlled system. The direct methods operate with low MPPT performance under rapid variation of wind speed and the superiority of variable step size is not significant since the dynamic process of the perturbation strongly weakens the effect of MPPT algorithm.