Siemens SINAMICS S120 - Converter Efficiency at Partial Load; Partial Load Efficiency of S120 Basic Line Modules

Fundamental Principles and System Description
Engineering Information
SINAMICS Engineering Manual – November 2015
Ó Siemens AG
184/528
The power losses P
L-100
of the converters at full load are device-specific values and can be found either in the
Catalogs D 11 or D 21.3 or in the operating instructions (equipment manuals).
The efficiency of the converter η
100
at full load is calculated on the basis of the active electrical output over P
Out-100
and the power losses P
L-100
according to the formula
( )
100
100100
100
100
cos3
cos3
--
-
--
-
+×××
×××
»
+
=
LMotratedOutLine
MotratedOutLine
LOut
Out
PIV
IV
PP
P
j
j
h
. (3)
This formula can be applied to individually calculate the full load efficiency of the SINAMICS converters as a function
of the line voltage and the power factor of the connected motor.
If the efficiency calculation for SINAMICS converters is performed on the basis of a typical power factor of
cosφ
Mot
= 0.88 (4-pole asynchronous motors in the power range from 100 kW to 1000 kW), the following typical
converter efficiency factors at full load are obtained:
· SINAMICS G130 and G150 with pulse frequency according to factory settings: η
100
= 97.7 % - 98.3 %.
· SINAMICS S150 with pulse frequency according to factory settings: η
100
= 96.0 % - 96.5 %.
1.14.2 Converter efficiency at partial load
1.14.2.1 – – –
1.14.2.2 Partial load efficiency of S120 Basic Line Modules
The chart below shows the partial-load efficiency of air-cooled and liquid-cooled SINAMICS S120 Basic Line
Modules. The calculations are based on a typical efficiency at full load of 99 %. The efficiency is represented as a
function of the active output power ratio P
Out
/P
Out-100
supplied by the BLM to the connected SINAMICS S120 Motor
Modules.
BLM efficiency in %
Efficiency of air-cooled and liquid-cooled S120 Basic Line Modules
as a function of the active output power ratio P
Out
/P
Out-100
in %