Page 210 - Power Electronics Handbook

The effect of source reactance 201
the less stringent inductance requirements of three-phase circuits so that
where continuous load current is required, from a low inductance load, the
pulse number of the circuit should be made as large as possible.

9.5 The efFect of source reactance

In the discussions so far the impedance of the a.c. lines has been omitted
for convenience. Generally, this would consist of the reactance of the
distribution transformer and any associated cabling, and for reasonably
'stiff supplies it may be neglected. There are instances, for example, when
the converter is operating from its own local generator, or the load current
approaches its short-circuit conditions, when this approximation is no
longer valid. The effect of source reactance on a converter can be
explained with reference to the single-phase bridge circuit of Figure 9.25,
in which THz and "€33 are conducting at time to and feeding power back

r
Converter input

9.25 Bridge two-pulse bi-dircctional converter with 8.c. source impedance