Hybrid Vane distance constant, damping, inertia

[cpedrazzi]

 Hi everybody!

I am confronted with the task of developing a yaw control simulation for a wind turbine using the NRG Hybrid vane.  I would like to simulate as accurately as possible the behaviour of the vane.  To give you an idea of the whole process, I will use a simulated wind turbulence file generated by the well known NWTC "TurbSim" program (http://wind.nrel.gov/designcodes/preprocessors/turbsim/), that simulates wind speed and direction with a 0.05 sec step in any given turbulence condition.    Then I would like to introduce in Simulink the motion equation of the wind vane, the typical second order sensor equation.  The simulation would provide a continuous stream of directions signals, and also show (hopefully) the occasional 360? turns that the vane performs in low winds (and in the turbulent wake of the wind turbine).   The simulation of the control system could adopt any desired algorithm to decide how and when to activate the yaw motor and stop them.  

 Having said this, as background, here are my questions:

1) What is the frequency of sampling the NRG Hybrid vane + Personality module?  In other words: how often will the direction signal be actualized? We are using the personality module with the vane mode "U5" (4-20 mA current loop).

2) Could you provide us all the mechanical constants of the vane?  For example:

2a) rotational inertia

2b) rotationaldamping

2c) distance constant (in the literature it does exist a distance constant also for a vane

 

In general, I would be grateful for every insight (equations, measures, ...) about the rotational behavior of the vane.

 

Thanks a lot & best regards

 

Claudio Pedrazzi

Senior Engineer

TEROM Wind Energy 

Bologna, Italy

[johng]

Hello Claudio,

That sounds like an interesting project. 

The Hybrid internal electronics are very fast. Both the hybrid anemometer and vane provide a continuous (square wave) output signal with frequency proportional to either wind speed or wind direction. 

As for the performance characteristics, we do not have official published specifications for the items you asked for. However, I've talked with our engineering department in order to get you some unofficial numbers to plug into your model. 

Unofficially, the answers are:     

Distance Constant = 1.5m (by experimental test)
Rotational Inertia =    270000 g*mm^2 (Per SolidWorks Model)
Rotational Damping = 0.2*critical (aerodynamic damping only (very low friction), experimental estimate)

I hope this helps you with your model! 

If you have any other questions, please don't hesitiate to contact us directly at support@nrgsystems.com.  

 

Thanks!

 

 

 

 

[cpedrazzi]

 Hallo Johng!

thanks a lot for your quick and competent "unofficial" answer.   I also believe that the project is interesting, and we are performing this in order to understand the behavior of the vane in our "low wind" small wind turbine (http://www.terom.it/ASP/Pages/eng/News.asp). 

In low wind, we do occasionally observe 360? turns of the vane, and even if they do not surprise me (because of wake turbulence from the blades), the control system is sometimes confused from this behavior, and we are trying to simulate it in MATLAB+SIMULINK environment.

One last question is:

Am I right in supposing that the "Hybrid Personality Module" does not introduce any additional sampling delay, that is, the continuous signal of variable frequency of which you speak still remains an (almost) continuous signal even after having been processed by the Personality Module?

 Thanks a lot and best regards from Italy

Claudio Pedrazzi

Senior Project Engineer 

TEROM Wind Energy

[BarryK]

The update rate of the Personality Module for Yaw Vane modes is approximately 10 Hz, that is, it updates its output about 10 times per second.