Active Control of Wind Turbine Rotor Torsional Vibration

Abstract

Transient and harmonic stresses in wind turbine rotor shafts contribute to gearbox failure. This paper investigates the reduction of rotor shaft torsional vibrations through active control of the generator torque. A 5 MW turbine model is used to test the procedure. A model of a permanent magnet synchronous generator is included as part of the wind turbine simulation. The simulations are carried out using the software FAST from the National Renewable Energy Laboratory (NREL). The PI and feedback linearized controller for the generator is derived together with the means for vibration isolation. Examples of steady, time varying, and turbulent wind are presented which all show significant reduction in the torsional oscillations.

Active damping of torsional resonance in wind turbine drivetrains

“…Equation (6) requires the measurement of a force while (8) requires the measurement of an acceleration. The quality of this measurement determines the extent that a value of unity for α will work in (7) or that the acceleration used in (8) will achieve the detuning desired in (10).…”

“…The DC component of torsion enables power generation. A band pass filter has been presented [7] for extracting the portion of the rotor torque needed for the absorber. The transfer function of this filter is …”

“…6. The generator was a permanent magnet synchronous generator (PMSG) previously reported [7,21] and the same parameters were used. The only exception is that the parameter c, used in (20), was set to 0.001 s. 7.…”

“…FAST, a wind turbine mechanical modeling software developed by the National Renewable Energy Laboratory (NREL) [4], has received widespread use. Of the literature already cited in this paper, there are several examples of the use of FAST [7,[11][12][13]. Analog models of wind turbines are also common.…”

“…The two mass model is the standard gearbox model used in FAST [4]. Several examples of the use of the two mass model have appeared in the literature [5][6][7]. The three mass model represents the turbine drivetrain with a rotor inertia, a generator inertia, and a lumped inertia for the gearbox representation.…”