An Innovative Method for Rotor Inertia Emulation at Wind Turbine Test Benches

Abstract

Recently wind industry paid a lot of attention to nacelle test benches in the multi MW class, which allow overall tests of wind turbine systems, including the control strategy. For several reasons the rotors of such turbines are dismounted at test benches, through which the dynamic properties of the system are changed significantly. This results in the challenge of having to emulate the missing rotational inertia for realistic wind turbine controller tests.In this paper an innovative method is proposed, which allows the emulation of the missing rotational inertia. The idea of the proposed method is to balance the inertia related torque by controlling the rotational impulse of the wind turbine's drive train. This has the advantage, that compared to a baseline approach, this method does not require a rigid drive train at the test bench to accurately emulate the rotor inertia. For this reason the proposed method reproduces the drive train's dynamics more accurately than the baseline approach and thereby allows for stable operation of the wind turbine controller. An experimental verification of the method was conducted at the world-wide first nacelle test bench.