| Abstract |
Due to non-linear loads or non-linear behaviour
of some elements, harmonics currents are injected in the
network generating a voltage distortion. To improve the
voltage quality, some passive filtering are used to trap these
harmonic currents. However a simple passive filter modifies
significantly the characteristics of the network by
generating a parallel resonance and can create some
problems of oscillations and instability when associated with
power electronics converters as Large Rectifiers or Static
Var Compensator. To avoid these problems, passive
damping with parallel resistors is generally introduced.
However this technique generates some losses in the whole
filter and alters the efficiency of the filtering. This paper
shows that dynamic damping with Voltage Source
Converter can contribute to improve the damping without
altering the filter efficiency and to optimise the whole losses
of the hybrid filter. Two industrial cases are presented:
Dynamic damping in the case of power supply and dynamic
damping in the case of shunt compensation. Extension of
this principle in a hybrid filter is presented in this paper
with regards on losses and sizing. This article shows the
strategic interest of small converters in AC filtering to make
it evolute in new techniques associating passive and active
elements to form hybrid dynamic damped filter. |
