A control scheme for maximizing the delivered power to the load in a standalone wind energy conversion system

摘要

In this paper, a control scheme is proposed for maximum power point tracking (MPPT) in a variable speed standalone wind energy conversion system (WECS) with permanent magnet synchronous generator. A MPPT algorithm is designed trying to eliminate the main deficiency of the conventional perturbation and observation (P&O) method, which is the challenge of choosing a proper step size and the unwanted trade-off between accuracy and speed. The designed algorithm properly addresses this drawback and significantly improves the MPPT performance. Another important issue is to ensure fast and accurate tracking of the optimal reference point obtained from the MPPT algorithm and improve the performance and efficiency of the control system for transferring maximum possible power to the load. To this end, a Vienna rectifier is used in the designed WECS and a multiobjective model predictive control scheme is designed to properly control the converter with fast response, high accuracy, and, at the same time, the lowest possible switching frequency. The performance of the proposed control scheme has been studied for two different wind speed profiles with different behaviors. Moreover, a comparison is made between the proposed MPPT algorithm and the conventional P&O method. The results support the proper performance of the proposed system in extraction and transfer of the maximum possible power from the wind to the load. This aim is achieved because of the significant advantages of the designed system in terms of fast and accurate tracking of the optimal point and having higher efficiency.