Wind
Turbine Tower-Nacelle Model with MR Tuned Vibration Absorber
The laboratory model of wind turbine
tower-nacelle system consists of vertically oriented titanium (Ti Gr.5) rod 1 (representing wind-turbine tower), and a set
of steel plates 2 (representing nacelle and turbine assemblies) fixed to
the top of the rod 1, with
Magnetorheological Tuned Mass Damper 3 (MR TMD) embedded. Titanium rod is rigidly mounted to the steel
foundation frame 4. MR TMD 3 is an additional mass moving horizontally along
linear bearing guides, connected with the assembly representing nacelle via
spring and Lord RD 1097-1 MR damper in parallel. MR TMD operates along the same
direction as vibration excitation applied to the system. Force generated by
vibration excitation system, i.e. force exciter TMS 2060E 5 with drive train assembly 6 of changeable leverage (enabling
changeable force / velocity amplitudes, and displacement range) may be applied
either to the rod 1 (modelling the
tower, as in the picture) or to the set of steel plates 2 modelling nacelle/turbine. Excitation
signal is generated by LDS Dactron 7 and amplified by TMS 2100E21-400 8.
Measurement and control system consists of
laser vibrometer with its controller 9, laser displacement transducer 10, LVDT relative displacement transducer 11, tensometric stress transducers 12, force and acceleration transducers (not apparent in the picture) as
well as transducers supply/conditioning system including MR damper signal
amplifier 13, and measuring-control PC 14 with Windows XP/MATLAB/Simulink/RT-CON
applications.
The laboratory test rig of wind turbine
tower-nacelle system with MR Tuned Vibration Absorber
The laboratory test rig gives the
possibility to model wind turbine tower vibration under various excitation
sources as variable wind conditions, including wind shear, Karman vortices,
blade passing effect, rotating elements unbalance, sea waves, ice, etc. Several
vibration control algorithms are tested with the help of this rig. MR damper,
which force depends on the current fed to its coil, serves as an actuator of
the control system. With the use of the MR damper, standard TMD linear damping
algorithm may be realised as well as other dedicated solutions as ground-hook
and its improvements, nonlinear damping, sliding mode, optimal and fuzzy
control, etc. Moreover, the rig may be laid down on the horizontally excited
platform to model vibration due to seismic, or sea waves (for buoy-floating
structures).
Several didactic activities are realised
using this test rig, including e.g. tower-nacelle system behaviour demonstration
under various frequency values and excitation source models (as specified
above), especially in relation with system natural frequencies, determination of MR damper dissipation
energy for each vibration period in relation with the excitation frequency and
MR damper control current.
Project financed by the Polish National Science Centre
(Narodowe Centrum Nauki) (contract no. 2286/B/T02/2011/40).