LPV pitch control of a hydrostatic wind turbine based on LIDAR preview

Abstract

We transform the NREL (National Renewable Energy Laboratory) 5-MW geared equipped monopile wind turbine model into a hydrostatic wind turbine (HWT) by replacing its drivetrain with a hydrostatic transmission (HST) drivetrain. Here we focus on the design of blade pitch controller for the HWT using a linear parameter varying (LPV) control algorithm. To enhance performances of the pitch control system during the transition region around the rated wind speed, we add an anti-windup (AW) compensator to the LPV controller, which would otherwise have had undesirable system response due to pitch saturation. Both the pitch controller and its AW compensator use the steady rotor effective wind speed as the scheduling parameter which is estimated by LIDAR (Light Detection and Ranging) preview. We test the LPV pitch controller (with and without AW) based on the transformed NREL 5WM HWT model, which has shown much improved overall performances over the gain-scheduled PI pitch controller.