User`s manual
172 • Vacon apfiff09 marine
Tel. +358
6
7.8.4.4
Voltage stabiliser
The voltage stabilizer is similar to the torque stabilizer controlling the change in DC-link voltage at
frequencies above 3 Hz. It is a first order high-pass filter for the measured DC-link voltage
. The
output of the filter is a frequency correction term added to the output frequency reference. Gain
is adjusted relative to the estimated torque. As the torque increases from 10% to 50 % of the motor
nominal torque, the controller gain decreases from the voltage stabiliser Gain down to zero. The
gain and the corner frequency of the filter are controlled by the following parameters:
P2.8.6.9 Voltage stabiliser TC ID1552
This parameter defines the corner frequency of the high-pass filter. The time constant of
the filter is calculated as
P2.8.6.8 Voltage stabiliser Gain ID1738
Voltage Stabilizer Gain is a function of a torque. If the torque is below 15%, the gain is the
value defined by the Voltage Stabilizer Gain. If the torque is above 50% the gain is 0.
Between 15-50% the gain decreases linearly with the torque from Voltage Stabilizer Gain
to 0. In other words,
The final gain is obtained by considering the value of Voltage stabiliser TC and the
scaling in which 256 means the gain 1. So, the final and the actual gain of the filter is
obtained from
P2.8.6.10 Voltage stabiliser Limit ID1553
This parameter sets the limits for the voltage stabilizer output.
The maximum and the minimum value for the correction term in FreqScale.