Danfoss Vacon NXP Applications Manual page 92

90 · vacon
2.7.4 Start Delay
This parameter defines a starting delay when a run command is given. When
programming different delays to parallel units, the units will start in sequence. This is
necessary in parallel units to make sure that the synchronisation does not happen
simultaneously in all the drives. A simultaneous start can lead to a failed
synchronisation. The recommended value between the drives is 500 ms.
2.7.5 Modulator Type (ID1516)
With this parameter you can change the modulator type. With an ASIC (HW) modulator,
the current distortion is lower, but losses are higher compared to a software modulator.
It is recommended to use Software modulator 1 as a default option.
0 = Hardware modulator: an ASIC modulator, with a classical third harmonic injection.
The spectrum is slightly better compared to Software 1 modulator.
1 = Software modulator 1: A symmetric vector modulator with symmetrical zero
vectors. The current distortion is smaller than with Software modulator 2 if boosting is
used.
2 = Software modulator 2: A symmetric BusClamb, in which one switch always
conducts 60 degrees either to a negative or a positive DC-rail. Switching losses are
reduced without different heating of upper and lower switches. The spectrum is narrow.
Not recommended for parallel units.
3 = Software modulator 3: An unsymmetric BusClamb, in which one switch always
conducts 120 degrees to a negative DC-rail to reduce switching losses. The upper and
lower switches are unevenly loaded and the spectrum is wide. Not recommended for
parallel units.
4 = Software modulator 4: A pure sine wave, sinusoidal modulator without harmonic
injection. It is dedicated to be used, for example, in back-to-back test benches to avoid a
circulating third harmonic current. The required DC voltage is 15% higher compared to
other modulator types.
5
Run
AFE 4
Stop
Run
AFE 3
Stop
Run
AFE 2
Stop
Run
AFE 1
Stop
Description of parameters
Time * 500 ms
Figure 35.
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