Thermal Monitoring And Overload Responses - Siemens SINAMICS G150 Operating Instructions Manual

9.4.2

Thermal monitoring and overload responses

Description
The thermal power module monitor is responsible for identifying critical situations. Possible
reactions can be assigned and used when alarm thresholds are exceeded to enable
continued operation (e.g., with reduced power) and prevent immediate shutdown. The
parameterization options, however, only enable intervention below the shutdown thresholds,
which cannot be changed by the user.
The following thermal monitoring options are available:
● i²t monitoring – A07805 – F30005
● Heat sink temperature – A05000 – F30004
● Chip temperature – A05001 – F30025
If an overload occurs with respect to any of these three monitoring functions, an alarm is first
output. The alarm threshold p0294 (i²t monitoring) can be parameterized relative to the
shutdown (trip) values.
Example
The temperature difference between two sensors must not exceed 15 Kelvin (K); a
temperature difference of 5 K is set for the temperature monitoring of the heat sink and the
air intake. This means that 15 K or 5 K below the shutdown threshold an alarm is issued
regarding the pending overtemperature. Parameter p0294 merely allows a change in the
alarm threshold so that an alarm is received earlier and, if necessary, steps can be taken to
intervene in the drive process (e.g., reduce the load, reduce the ambient temperature).
Converter cabinet units
Operating Instructions, 03/2012, A5E03263466A
i²t monitoring is used to protect components that have a high thermal time constant
compared with semi-conductors. Overload with regard to i²t is present when the converter
load (r0036) is greater than 100% (load as a % of rated operation).
Used to monitor the temperature r0037[0] of the heat sinks on the power semiconductors
(IGBT).
Significant temperature differences can occur between the barrier layer of the IGBT and
the heatsink. The calculated barrier junction temperature is displayed in r0037[13...18];
the monitoring ensures that the specified maximum barrier junction temperature is not
exceeded.
Functions, Monitoring, and Protective Functions
9.4 Monitoring and protective functions
497