A friend in England has been working with a prototype wind mill following some of my suggestions,
You can down load the PDF he is writing
http://www.martinslade.freeserve.co.uk/Prototype%2010Kw%20Wind%20turbine.pdf
I would like your read comments
Nando
bob golding
Can you detail the control setup?
Very interesting! Thanks for sharing Nando! Simon has a lot of wind!
bob golding[ Parent ]
Nando [ Parent ]
I do not have the setting of the Pitch control for maximum power available at the present, the pitch control is via the mechanical setup and not via the PLC.
The AVR of the generator is not connected, the PLC supplies PWM to the rotor field.
The PLC is used to modulate the Rotor field current to attain the MPPT power and to keep the RPM limited to less than 200 RPM.
Simon is out of the country right now and he plans to convert the spring & weights pitch control to Pitch control via generator torque for several reasons, one if the generator does not need to produce power the blades will go into feathering, automatically, to a low RPM setting ( just low enough to have some voltage to return to its wind pitch control setting, when loaded) and to limit the maximum power automatically, he did this present pitch control because he had it drawn and handy, he has mechanical equipment in his farm ( lathe, milling machine etc).
More writing will be done later with more details.
The PLC is handy and has a lot of additional capabilities and I think data logging and data displayed or send to a PC. By the way, we started with a 5 KW Chinese wind mill, Oh God !!.
DAN: As you can see, not that complicated and the pitch control via torque would be better and NO furling needed.
Without any doubt, One needs to understand the procedure to be able to implement a solution to the problem .
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ One needs to think what is happening with a Pitch with torque control to define the mill over speed.
Torque control sets the angle of attack of the blades and nothing else -- so if the torque is defined -- so it is the power, therefore if no torque, the power goes toward down to a minimum (normally toward Zero) though Zero is not possible due to the mechanical factors and the blades profile.
The end result is that when NO load, the blades go into almost feathering, and can be done in such a way that the RPM is just LOW enough to generate some voltage for the system to re-start when the load appears again.
Torque operated Pitch control can be designed to include parking, for those cases of high gale conditions -- though complicated to implement and probably impractical for small wind mills.
One way is to have a blade profile in such a way that after certain angle of attack the upper length of the blades (tips) starts to present a negative rotating force, causing the equivalent of shorting the blades at different wind velocities and at the same time giving the equivalent of reduced TSR, toward below 1.
For generators producing grid power, the Torque Pitch controlled presents the opportunity for the generator to have a wider operating range, in addition there are other hub implementations additions that allow faster pitch adjustments to keep the generator producing power at the GRID frequency.
Therefore if the Torque Pitch Controlled is unloaded, it goes toward minimum RPM, even when high winds exists.
ADDING TO THE MESSAGE: The Torque Pitch Controller HUB is floating on the generator shaft and the Pitch arm is against the Shaft arm and when the generator loads the arm of the shaft pushes the Pitch arm into the angle necessary to produce the torque that the generator is "requesting".
Nando[ Parent ]
if i am understanding all this correctly, you are using generator also as some kind of brake as you use it normally as a producer of energy. is this correct?
making generator harder to turn and reducing rotation speed?
i have heard about something like this, but this is the first i have been seeing explained any way.
what is meaning of short PLC? MPTT?
thank you
dalibor
