.WindPowerPlants.Blocks.TorqueLimiter .WindPowerPlants.Blocks.TorqueLimiter
The torque output of the angular velocity control is limited
to avoid significant dynamics around zero speed and
for negative speeds. Since the electric machine is operated
as generator, the mechanical power is negative.
The generator is operated at positive angular
speed w and thus torque tau is negative. Torque limitation,
however, is implemented as function of speed.
The characteristic of the torque limiter is shown the figure below
for
tauRef = 10kNm. However, In the investigated case the reference
speed wRef = 50*pi rad/s. For positive speeds
greater than linear = 2% of the reference speed the torque is not
limited. The range between zero angular speed and 2%
of the reference speed torque is limited by the steep linear
curve shown in the figure below. In the negative speed range -
which shall never be reached - torque is limited linearly
towards the negative reference angular velocity. In the vicinity of zero speed
torque is limited by limit = 2% with respect to tauRef.
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