Pulse Frequency Wobbling - Siemens SINAMICS S120 Function Manual

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Pulse frequency wobbling

The "Pulse frequency wobbling" function is only available for vector control and for Motor

Modules in Chassis format with DRIVE-CLiQ (article numbers: 6SL3...-.....-...3).

Function description

The function damps the spectral components, which can generate unwanted noise in the

motor. Wobbling can be activated only for pulse frequencies that are ≤ the current controller

frequency (see also p0115[0]).

Wobbling causes the pulse frequency in a modulation interval to deviate from the setpoint

frequency. This means that the actual pulse frequency might be higher than the average pulse

frequency required. A noise generator can be used to vary the pulse frequency around an

average value. In this case, the average pulse frequency is equal to the setpoint pulse

frequency. The pulse frequency can be varied in every current controller cycle if the cycle is

constant. Current measurement errors resulting from asynchronous pulse and control intervals

are compensated by a correction in the actual current value.

Pulse frequency wobbling can be parameterized with parameter p1810 "Modulator

configuration".

Parameter p1811[0...n] "Pulse frequency wobbling amplitude" can be set to adjust the

magnitude of variation in the pulse frequency wobble to between 0 and 20%. The factory setting

is 0%. For a wobble amplitude of p1811 = 0 %, the maximum possible pulse frequency is

p1800 = 2 · 1/current controller cycle (1000/p0115[0]). With a wobble amplitude setting of

p1811 > 0, the maximum possible pulse frequency is p1800 = 1/current controller cycle (1000/

p0115[0]). These conditions apply to all indices.

If pulse frequency wobbling is deactivated, parameter p1811 is set to "0" in all of the indices.

Overview of important parameters (see SINAMICS S120/S150 List Manual)

● p1811[0...n]

Drive functions

Function Manual, 06/2019, 6SL3097-5AB00-0BP2

Modulator configuration

Pulse frequency wobbling amplitude

Basic functions

8.9 Pulse frequency wobbling