July 2013 6.8 The control loop 885
Regenerative module (= (4) in commissioning flow chart)
The DC-link voltage for regenerative power modules is independent of the line
voltage UNetz. On regenerative HEIDENHAIN power modules it is 650 V
(MP2190.x = 650) and on the regenerative Siemens modules 600 V or 625 V
(MP2190.x = 600/625).
Actual DC-line voltage on non-regenerative power modules (= (5) in the
commissioning flow chart)
Entering the DC-link voltage in MP2190 is also used by the control to ascertain
the magnetizing current. At a line voltage of 400 V (interlinked), the rectified
DC-link voltage is 565 V. If the fluctuation range of the line voltage is known
(e.g. +/– 10 %), use the minimum value UNetz,Min of the line voltage to
calculate the DC-link voltage according to the following equation:
If in addition you use a series reactor—for example to comply with EMC
standard—then remember that the DC-link voltage can be reduced. So enter,
if possible, the measured value of the DC-link voltage. If a measurement is not
possible, then reduce the value calculated on the basis of the line voltage by
approx. 3 %.
Example: Line voltage UNetz = 380 V =>
MP2190 = 0.97 * 537 = 521.
If the line voltage in the machine's work area is less than the line voltage
during commissioning, enter the value of the DC-link voltage at its later
location during commissioning.
Stationary line voltage stable? (= (6) in the commissioning flow chart)
Any stationary fluctuating line voltage is to be accounted for by using the
smallest occurring value for calculating the entry in MP2190, insofar as it has
not already been accounted for through minimum line voltage. This ensures
that the required magnetizing current is available, in particular during the
acceleration phase. An excessively large DC-link voltage could lead to
increased following error during acceleration and at high speeds.
Line voltage stable under load? (= (7) in the commissioning flow chart)
If you use an unstable power network on the machine, it can reduce the line
voltage under load (when the axes are accelerated) and therefore also reduce
the DC-link voltage. So it might be necessary to adjust the entry in MP2190 for
the load. Compare the behavior of one axis during acceleration of only that axis
(light load) with its behavior during acceleration of all axes, perhaps including
the spindle (maximum load). If there are no differences in the following error
or nominal current, the entry in MP2190 can remain unchanged. If these
signals show anything unusual (surge in current or following error), reduce the
entry in MP2190 accordingly.
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