Model Predictive Control of PMSG-Based Wind Turbines for Frequency Regulation in an Isolated Grid

Abstract

This paper proposes a frequency regulation strategy applied to wind turbine generators (WTGs) in an isolated grid. In order to complement active power shortage caused by load or wind speed change, an improved deloading method is proposed to improve the regulation capabilities in different speed sections and to provide WTG power reserves. Considering torque compensation may cause power fluctuation, speed reference of a conventional pitch control system should be reset. Moreover, to suppress disturbances caused by load and wind speed, as well as overcome the dependence on system parameters, a model predictive control (MPC) method is presented to generate torque compensation for each deloaded WTG, which allows each WTG to react to the disturbance differently, depending on its generator speed and the frequency deviation. Hardware-in-the-loop simulation and experimental results show that the proposed strategy can enhance the frequency response ability during load changes, and smooth power fluctuations resulting from wind speed variations.