Comparative analysis of MPPT techniques and Optimal Control for a PMSG-based WECS

Abstract

This paper presents a comparative study about different schemes for maximum power point tracking (MPPT) for Wind Energy Conversion Systems (WECS) based on Permanent Magnet Synchronous Generator (PMSG). Owing to the inherent changing nature of the wind, it is required to have techniques capable of fulfill the task of extracting the maximum available power at any time by tracking some system variables such as rotor speed, torque, power among others. Therefore, including a controller that can track the maximum power point in any wind speed scenario is essential. This paper analyzes four MPPT techniques, Power Signal Feedback (PSF), Tip Speed Ratio (TSR) control, Perturb and Observe Method (P&O) and Optimal Torque (OT) control using a wind speed estimator for the schemes that require such measurement. A comparison of the performance of these MPPT algorithms has been made under a varying wind speed scenario to examine its characteristics such as efficiency and ease of implementation. A nonlinear optimal control scheme based on a State Dependent Coefficient Factorization (SDCF) was designed to track the trajectories generated by the MPPT algorithms. Simulations results developed in Simulink are presented to show the characteristics and performance of each technique.