Current Setpoint Filter - Siemens SINAMICS S120 Function Manual

Operating Modes
Servo control
3.1.7

Current setpoint filter

The four current setpoint filters connected in series can be parameterized as fol-
lows:
S Low-pass 2nd order (PT2): --40dB/decade)
S General filter 2nd order
Band-stop and low-pass with reduction are converted to the parameters of the
general filter 2nd order via STARTER.
-- Band-stop
-- Low-pass with reduction by a constant value
The phase frequency curve is shown alongside the amplitude log frequency curve.
A phase shift results in a control system delay and should be kept to a minimum.
General 2nd-order filter
Transfer function:
H
=
(s)

s
2πf
Characteristic frequency f
Damping D
Table 3-2 Example of a PT2 filter
STARTER filter parameters
Characteristic frequency f
500 Hz
Damping D 0.7 dB
N
3-80
1
2

2D N
⋅ s + 1
+
2πf
N N
N
N
Amplitude log frequency curve
N
Phase frequency curve
© Siemens AG, 2005. All rights reserved
SINAMICS S120 Function Manual, 06/05 Edition