NREL Fast Modeling for Blade Load Control with Plasma Actuators

Reducing extreme and fatigue loads on the rotor blades of a wind turbine lowers the Levelized Cost of Energy (LCOE), which is particularly critical for future wind turbines equipped with longer and more flexible blades. With larger rotors, the span-wise variability of the wind challenges the capabilities of the blade load control strategies of current operational systems. Active flow control (AFC) has emerged as an appealing solution to fast and localized rotor control for load mitigation and energy capture enhancement. Among the existing AFC devices, plasma actuators have drawn attention due to their mechanical simplicity (no moving parts), fast response time and low cost. This paper presents a simulation tool for design of plasma-based AFC systems for blade load reduction. The tool is based on the NREL FAST code. The FAST module with integrated plasma actuation is demonstrated using the NREL 5-MW reference turbine in above-rated wind conditions (Region 3). With the feedback of blade-root flapwise bending moments, a Coleman transformation based controller is used to drive the voltage commands to the plasma actuators. Load reduction is observed without noticeable penalty in turbine performance as measured by rotor speed and power errors in Region 3.