The attached example (WindCpLambda.pfd) visualises the aerodynamic efficiency cp of the wind turbine, which can be found in the DFIG (doubly fed induction generator) template. Here the cp-lambda characteristic for different pitch angles is shown:
• beta = 0°
• beta = 5°
• beta = 10°
• beta = 15°
• beta = 20°
• beta = 25°

The function cp=f(beta,lambda) is realised using a spline approximation of a series of cp-lambda characteristics. The DSL command sapprox2 is used for this purpose. The attached project contains only multiple modified common models to show the curve for different pitch angles (beta). For demonstration purpose an integrator is added, which increases the tip speed ratio (lambda). All values are displayed together in one plot, sharing the same x-axis (this is the tip
speed ratio). The value is limited to be larger than zero.
The cp-lambda characteristic is stored on the second page of each common model in the project.