Galvanically isolatedgatedrive in parallel connection
The advantage of this type of control in parallel connection is that it prevents
compensating currents in the gate paths. Dynamic compensating currents cannot flow
due to the galvanic isolation of the control signals and the auxiliary supply. This means
that the symmetry of the load currents no longer depends on the output inductance of
the individual IGBT and, if the gate drive is constructed symmetrically, is no longer
dependent on the gate path. There are no oscillations between the gates.
shows, as an example, a galvanically isolated control for parallel connection with three
IGBTmodules and oneSCALE-2gate drive, which shows a jitter <8ns.
As the supply voltage for the IGBT gates is also of utmost importance, an active voltage
control of the secondary side (IGBT side of the driver stage) is recommended.
Deviations in the turn-onand turn-off voltages per driver stage for each paralleled switch
of as lowas 500mVwill lead to imbalanced commutation times
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