55 Commander SE User Guide
www.controltechniques.com Issue Number 8
Using Intelligent Thermal Management the drive will automatically reduce the IGBT
switching frequency, if set above 3kHz, to try and prevent the drive from tripping on
heatsink overtemperature. This will depend on load conditions, heatsink temperature and
the operating output frequency of the drive. The following table indicates how the
switching frequency is controlled:
*Commander SE Size 4 >100°C
0 - no autotune
1 - non-rotating static autotune
2 - rotating autotune
There are two levels of autotune that can be performed by the Commander SE.
Non-rotating static autotune
This autotune measures the motor stator resistance and system voltage offset. The
results of the test are stored in the appropriate parameters. After the test is carried out,
the motor will run as requested.
The motor must be at standstill before this test is initiated.
Rotating autotune
The drive will always carry out a rotating autotune on the motor in the forward
direction of motor rotation even if the run reverse command is given to initiate the
autotune routine.
In addition to the stator resistance and system voltage offset, the rated magnetising
current and total system leakage inductance are measured. The motor is accelerated up
to
2
/
3
rated speed in the forward direction of motor rotation to measure the rated
magnetising current. The speed will be less if insufficient DC Bus voltage is available to
operate at
2
/
3
rated speed without field weakening. After this autotune has been carried
out, the run forward or run reverse terminal will need to be opened and closed to allow
the motor to run.
The stator resistance and voltage offset are stored in their appropriate parameters. The
rated magnetising current and total system leakage inductance are used to set up the
motor rated power factor (parameter 09).
The motor must be at standstill and unloaded before this test is initiated.
The main advantage of carrying out a rotating autotune over a non-rotating autotune is
that the drive calculates the correct power factor, rated torque current and magnetising
current for the motor. This will give more accurate slip compensation (if enabled).
Autotune Procedure
Before a non-rotating static autotune is carried out, the drive’s motor map parameters
should be correctly set:
Drive Condition Action
Heatsink >95°C* Trip drive
Heatsink >92°C Reduce switching frequency to 3kHz
Heatsink >88°C Reduce switching frequency to 6kHz
Heatsink <85°C and IGBT temperature at new
switching frequency <135°C
Allow an increase in switching frequency
IGBT temperature >135°C
Reduce switching frequency
If it is already 3kHz, trip drive
No. Function Type Limitations Range Units Defaults
38
Autotune
RW U 0 - 2
0EUR
0USA
NOTE
NOTE
NOTE
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