Siemens SINAMICS PERFECT HARMONY GH180, Function Manual

Page: 336 / 538

8.24.3 Damping of Resonance due to Output Cable
Damping of Resonance due to Output Cable
With SINAMICS Perfect Harmony™ GH180 drives, the output filter can cosnsist of a reactor-
capacitor (LC) filter or a reactor only (L) filter. When a LC filter is used, the resonance due to the
filter can be damped by the drive using the parameters in the "Output Connection" Menu and
with "Filter CTs" selected for the "Filter Currents Source" parameter (ID 2918)
When an output reactor (L only) is used as the output filter, the output cables may or may not
introduce a resonance frequency that interacts with the control of th drive. Typically, an
interaction with the drive control occurs when the resonance frequency of the output circuit
(including the filter reactor and output cables) is around 1 kHz or lower. In such cases,
capacitance of the output cables is in the same range as the capacitance in a typical output
filter. The resonance frequency can be damped by the drive when "Output CTs" is selected in the
"Filter Currents Source" parameter (ID 2918). When this selection is made, the control uses
information in the output current to create a virtual resistor for damping the resonance.
Parameters that need to be entered are:
Cable Inductance - (ID 2941) This should represent the total inductance in the output circuit (including cable
inductance and any output transformer inductance). Enter in percent of drive
base inductance.
Filter Inductance - (ID 2920) Set the output filter inductor (i.e., impedance value as a ratio of the base output
impedance of the drive, typically 5 %)
Filter Capacitance - (ID 2930) Set the filter capacitance parameter to the output cable parasitic capacitance as
a ration of the base output admittance of the drive. Admittance is the inverse of
impedance.
Filter Damping Gain - (ID 2950) Contact Customer service for detailed information.
8.24.4 Operating Parallel Motors over Long Cables
The drive has the capability to operate parallel induction motors over long cables using the cable
inductance compensation parameter (2941).
For operation with two parallel motors connected to the same drive to work correctly the cable
length and characteristic requirements must be met.
Additional output filtering may be required for extremely long cables to compensate for
transmission line effects of the cable impedances and length. Siemens will calculate the
impedance values and need for filtering.
Stability can be an issue due to cable resonance. This is helped by reducing the current loop gains
and reducing the dead time compensation as needed.
Advanced Operating Functions
8.24 Long Cable Applications
Control Manual
334
Operating Manual, A5E50491925A