The value of the generator torque can be changed during the simulation in the Live controls box.

The following parameters can be modified:

Rating and efficiency

Rated power scheme

Decides how the rated electrical power of the generator is found.


From rotor area:

The rated electrical power is calculated based on the rotor area and the target (rated) wind speed.

User defined (default):

The rated electrical power is set by you.

Rated electrical power

The rated electrical power of the generator (i.e. power 'delivered to the grid'). The corresponding rated mechanical power is higher than this because the generator's efficiency is less than 100%.

  • Default value: 5e+06
  • Unit: $\text{W}$
  • Range: 0 — 1e+08

Target wind speed

The target wind speed to be used to calculate the target (or rated) mechanical and electrical power of the generator.

This parameter is only visible (and relevant) if Rated power scheme is set to From rotor area. In addition to this wind speed, the rotor area and the air density is used to calculate the target (rated) mechanical power

  • Default value: 12
  • Unit: ${\text{m}} \over {\text{s}}$
  • Range: 1 — 100

Rated RPM

The generator RPM when the rated power is reached. For higher RPM the blades will typically pitch to decrease the efficency and thus keep the power from exceeding the rated power.

  • Default value: 1173.7
  • Unit: $\text{rpm}$
  • Range: 0 — 1e+08

Efficiency factor

The efficiency of a generator is the ratio of input mechanical power to output electrical power. The efficiency factor is used to calculate the efficiency of the generator. The default behavior is that the efficiency is equal to the efficiency factor (and thus constant). However, some generators calculate an efficiency explicitly (e.g. the PMSG generators), and for these generators the calculated efficiency is reduced with the efficiency factor. If no such reduction is desired, the factor should be set to 1. The value of the efficiency factor ranges from 0.01 to 1.00 (1% to 100%).

  • Default value: 0.944
  • Unit:
  • Range: 0.01 — 1

Drivetrain efficiency factor

The drivetrain efficiency is the ratio of mechanical driving (aerodynamic) torque to braking (generator) torque. Thus mechanical loss in the drivetrain is: loss = 1 - efficiency factor. The generator torque is divided with the factor before it is applied (i.e. the generator torque is increased to model the mechanical losses). The value of the efficiency factor ranges from 0.01 to 1.00 (1% to 100%). A value of 1 means no losses.

  • Default value: 1
  • Unit:
  • Range: 0.01 — 1


The rotational speed (RPM) of the generator can be filtered before use. Filtering is used to mitigate high-frequency excitation of the control systems, so filtering is recommended. The rotational speed is used to calculate the generator torque etc. and in the pitch control system to caclulate pitch.



The real, physical RPM is used directly.

Recursive, single-pole (default):

Recursive, single-pole low-pass filter with exponential smoothing, see (Jonkman, 2009).

Corner frequency

The corner frequency. Used in a low pass-filter to calculate the filtered RPM. Suggested value is one-quarter of the blade's first edgewise natural frequency.

  • Default value: 0.25
  • Unit: $\text{Hz}$
  • Range: 0 — 1e+12