On power tracking and alleviation by a new controller for fulfilment of the damping and performance requisites for a variable speed wind system: An optimal approach

• A precise and reduced model for a variable speed wind system is developed.
• Power regulation and mitigation are accomplished by the proposed approach.
• The proposed strategy has complied with both requirements of damping and performance.
• Based on linear quadratic function, the performance index is incorporated into damping requisite.
• A state feedback controller is tuned finely by a new optimal approach.

This paper addresses a new control strategy for a variable wind energy conversion system. The proposed controller aims to regulate the output power tightly in response to the desired value changes and alleviate power oscillations against the disturbances, including wind speed variation and fluctuation of the voltage magnitude, as voltage sag and swell. For the sake of straightforward analysis, an effective and reduced representation for the wind system is developed. In addition to the proper performance, the controller seeks to adequately fulfilment the damping requirements, as though both damping and performance requisites are taken into account control policy. Consequently, the proposed approach focuses on optimal tuning based upon a performance index incorporated into linear quadratic (LQ) cost function, which is subjected to the performance constraints. To validate the controller role, multiple simulation tests are carried out including set point tracking, disturbance rejection against wind speed, voltage sag and swell. Simulation results verify the proposed method features a satisfactory performance and sufficient damping, meeting both aspirations of the power regulation and disturbance suppression.