Danfoss VLT AutomationDrive FC 300, Руководство по программированию

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7-06 Speed PID Lowpass Filter Time
Range: Function:
Application
dependent
*
[1.0 -
100.0
ms] Set a time constant for the speed control
low-pass filter. The low-pass filter
improves steady-state performance and
dampens oscillations on the feedback
signal. This is an advantage if there is a
great amount on noise in the system, see
illustration below. For example, if a time
constant (τ) of 100 ms is programmed, the
cut-off frequency for the low-pass filter
will be 1/0.1= 10 RAD/sec., corresponding
to (10/2 x π) = 1.6 Hz. The PID regulator
only regulates a feedback signal that
varies by a frequency of less than 1.6 Hz. If
the feedback signal varies by a higher
frequency than 1.6 Hz, the PID regulator
does not react.
Practical settings of
7-06 Speed PID
Lowpass Filter Time taken from the number
of pulses per revolutions from encoder:
Encoder PPR 7-06 Speed PID
Lowpass Filter Time
512 10 ms
1024 5 ms
2048 2 ms
4096 1 ms
Note that severe filtering can be
detrimental to dynamic performance.
This parameter is used with
1-00 Configu-
ration Mode Speed closed loop [1] and
Torque [2] control.
The filter time in flux sensorless must be
adjusted to 3-5 ms.
0.6
0.6
f
g
= 10 Hz
175ZA293.11
Feedback
Disturbed feedback signal
t (Sec.)
t (Sec.)
Filtered feedback signal
Lowpass filter
Feedback
Parameter Descriptions FC 300 Programming Guide
98 MG.33.MB.02 - VLT
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