Abstract
M.Ing.
A non-linear load that draws distorted currents from the supply cannot be compensated
with classic compensation methods, but has to be compensated by a fast power electronic
source of reactive power. Power electronic switches are subjected to electrical extremes when switched from a stiff
DC supply. The input voltage to a voltage fed converter can be cyclically reduced to zero
by the placing of a relatively small inductor and capacitor in the input of the converter.
The switching elements in the converter may change state during these zero voltage
instants without incurring switching losses.
A voltage fed converter with high frequency resonant link snubber and reactive loading as
power filter will be discussed in this thesis. A charged capacitor forms the fast source of
reactive power. The resonant link is optimized for the application. Gate turn-off
thyristors are used as the switching elements and are characterized according to their turn-off
losses under resonant link operation. The gate drive, control and protection circuitry for
the system are discussed. A single and three phase resonant link power filter with split
supplies are discussed.