Load-following for wind turbines with permanent magnet synchronous generators

As new wind energy assets are installed at an accelerated pace and wind turbine technology continues to mature, permanent magnet synchronous generators (PMSG) are increasingly being utilized to derive electricity within wind energy conversion systems (WECS). Attractive as renewable sources, unfortunately WECS can introduce electrical instabilities into some power systems due to the intermittent nature of wind. Examples of problematic applications include: islanded or isolated power systems, as well as weak feeders that do not enjoy robust voltage and frequency control. PMSG technology and modern power electronic switch devices offer the opportunity to help overcome this common drawback of WECS applications. In this paper, a load-following mode-of-operation control scheme is presented that facilitates the use of modern PMSG-equipped WECS in applications where generation-to-load matching is desirable. Fundamentals of wind turbine operation are surveyed to support the case for generation control, as well as the development of a PMSG dynamic model and WECS controllers capable of achieving robust load-following capability. Simulation results are given that show the viability of the proposed control system for the PMSG-equipped WECS under real-world wind and load conditions. Finally, the case is made for the need to incorporate load-following controllers into WECS for deployment in future microgrids that require mode-of-operation flexibility depending on varying scenarios.