The problems with a variable – speed turbine are presented in this document. The resonance frequencies that are taken into account in the planning phase, will be considered. The resonance can be lowered with the appropriate control measures. These measures are also detailed. In most cases the resonance point falls outside of the operating range, but sometimes it’s proximity warrants that it be taken into account.
Creating models is also important. The model of the drive-train can be modeled in a lot of ways. In this document only the simplest cases will be considered. The model will be detailed in three parts, each part detailed fully. Using literature , the model’s certain transfer function will be drawn in a Bode diagram, and a phase diagram.
The controller will also be detailed. It has many functions and operating mechanisms, but only a handful will be presented. One solution will be presented, which is this: the nacelle will have an accelerometer built inside. This instrument measures the spatial deviation in the nacelle, and with it a better damping scheme can be implemented. The reason why this method is not widely implemented is because the pitch actuator will have to operate more often, and the instrument has to be of a certain quality ( so as not to cause any problems in the control schemes ).