Line Filters For The "First" Environment (Residential) And "Second" Environment (Industrial); Operating Principle Of Line Filters - Siemens SINAMICS G130 Engineering Manual

These classifications are therefore used to define the limit values for conducted interference emissions,
corresponding exactly to categories C1 to C3 as defined in EN 61800-3.
·
Class B1:
à This class corresponds to category C1 of EN 61800-3
·
Class A1:
à This class corresponds to category C2 of EN 61800-3
Class A2:
à This class corresponds to category C3 of EN 61800-3
1.5.3.2

Line filters for the "first" environment (residential) and "second" environment (industrial)

Line filters or RFI suppression filters limit the high-frequency harmonic effects on the supply systems of the drive by
reducing the conducted emissions in the frequency range between 150 kHz and 30 MHz. They ensure that the
disturbances produced by the variable-speed drive are mainly kept inside the drive system itself and that only a small
percentage (within the permissible tolerance range) can spread into the supply system.
The diagram below shows a variable-speed drive system which is connected to a TN system with grounded starpoint.
The drive system consists of a cabinet-mounted SINAMICS G130 Chassis unit which is feeding a motor over a
shielded motor cable. The purpose of this example is to explain the operating principle of the standard and optional
line filters.
I
PE
Variable-speed drive system PDS comprising a cabinet with a SINAMICS G130 Chassis and a motor
1.5.3.3

Operating principle of line filters

High-frequency interference in the variable-speed drive system is caused by the IGBTs (Insulated Gate Bipolar
Transistors) switching at high speed in the motor-side inverter of the converter unit. These switching operation
produces very high voltage rate-of-rise dv/dt. For further information about this phenomenon, please refer to the
section "Effects of using fast-switching power components (IGBTs)".
The high voltage rate-of-rise at the inverter output generates large, high-frequency leakage currents which flow to
ground across the capacitance of the motor cable and motor winding. These must return via a suitable path to their
source, i.e. the inverter. When shielded motor cables are used, the high-frequency leakage or interference currents
I pass via the shield to the PE busbar or the EMC shield busbar in the cabinet.
Leak
If the cabinet or the Chassis unit would not contain filters of any type which could offer this high-frequency
interference current a low-resistance return path to the inverter, then all the interference current would flow via the
line-side PE connection of the cabinet to the transformer neutral (I
(rectifier) via the three phases of the three-phase supply. If this were the case, the interference current would
superimpose high-frequency interference voltages on the line voltage and thus influence or even destroy other loads
connected to the same point of common coupling as the cabinet itself. The interference at the connection point would
match the level defined by category C4.
Fundamental Principles and System Description
SINAMICS Engineering Manual – November 2015
Engineering Information
I
= I ) and from there back to the converter
PE Leak
Ó Siemens AG
Leak
95/528