For low and medium wind turbine the optimum value of pitch angle is zero. So when we do dP/dw =0, we will get the optimum value of Cp and lambda. To do the same we will get dP/dw proportional to dCp/dw. But Cp is function (lambda, beta=0) and from the article i found that dCp/dw = (dCp/dlambdai)(dlambdai/dw). However lambdai is the variable it is the function of lambda and beta . For low and medium wind turbine lambdai=(1/lambda)-0.035.
So instead of dCp/dw = (dCp/dlambda)(dlambda/dw) how can we do dCp/dw = (dCp/dlambdai)(dlambdai/dw). Please clarify anybody regarding the same.
With Thanks and Regards
Rajin M Linus
As far as my point of view, i am thinking as follows. Please correct me if i am wrong
As we know CP= f(λ,β). Since the study is carried out for low and medium wind turbine β=0. Therefore CP=f(λ). The power is maximized only when (dP/dω) =0. Since λi=f(λ), CP=f(λi).
Hence dCP/dω = (dCP/dλi) (dλi/dω).
I agreed with Ana mam,
Iterative method is for finding Cp and lambda. But i need to know the maximum value of Cp and optimum value of lambda when we extract the maximum power. Since i am using PMSG as wind generator, no need of gearbox. So wind turbine output is maximum only when dP/dW=0. From this only we can get the maximum value of Cp and the optimum value of lambda. If i am wrong please correct me
Thank you for your valuable reply.
With thanks and Regards
Rajin M. Linus
The starting point is also wrong as you cannot assume beta is zero for optimal output - this will depend on the rotor/blade design and in particular the aero-foil section/s used and the blade twist distribution; and I'm not clear what you are trying to achieve, but you might find David Sharpe's chapter in the Wind Energy Handbook helpful.
The optimal value of Cp (assuming this needed to capture maximum energy) would depend on the aero-foil section and blade-twist distribution. Start with a good book such as the Wind Energy Handbook or Wind Energy Explained. You will need to write iterative program to 'draw' the Cp-lambda curve and then choose the best Cp.
How can i plot the graph of Cp Vs lamda for a fixed pitch angle and variable wind speeds on the same axis using simulink? i have the model for the turbine already, but the implementation on the same graph is my problem? Email; [email protected]
your suggestion will be so much appreciated
Let pitch angle input as 0 degree (For low and medium wind turbine)
Calculate the value of lambda using embedded block using the formula ( (speed * Radius)/ Wind velocity). In your model have own Cp value as the function of beta and lambda. Since the value of beta is zero and the embedded block provide lambda, you can calculate Cp using separate embedded block. I think, it will work out.
Thank you, Rajin M Linus for the response but how can i limit the lambda to let say 15 so that i can have a perfect curve, i try to use lambda=0:0.5:15; in the Cp embeded block but is given me error
Dear Kamilu. We have to make the generator to rotate in optimum speed. When the generator speed is optimum, the value of labda will be 8.1. Check the optimum value of lamda and Cp in the wind turbine model you have. Give a generator speed manually and vary it in step till the rated speed and tabulate it.
- Badges
- Science topic
- Similar topics
- Physical Sciences
- Energy
- Energy-Generating Resources
- Renewable Energy