FILTERS FOR ACTIVE POWER COMPENSATION INSTANT HARMONICS AND REACTIVE POWER.Author:
ROMAN LUMBRERAS MANUEL.
Year:
2005.
University:
POLITÉCNICA DE CATALUÑA [
www.upc.edu].
Place of defense: SALA D'ACTES EUETIB.
Place of preparation: COMTE D'URGELL, 187 DESPATX BA17 BARCELONA.
Summary: From last quarter of last century, and due to the big increase of electronic loads connected to mains, the existence of non-sinusoidal currents has been increased enormously, that is, the are a lot of harmonics in nowadays currents. This fact, in comparison to our environment, is named âelectric pollutionâ. The presence of this electronic loads exists in all power levels, from hundreds of VA till some MVA and, although the problem is worst as installed power is increased, it is not negligible the effect achieved by accumulation of so much small power loads. Due to this fact, specific regulations have been imposed. The conventional filter techniques, based on passive filter installation tuned at the supposed harmonics in the plant, became inadequate because of value and content variations of the harmonics as time passes. The presented work as a PhD. Thesis deals with nowadays techniques in order to eliminate the harmonics and, also, the conventional reactive energy, by means of Active Filter of Power techniques (AFP), based on the use of power electronics converters and specific control algorithms. The present work exposes the main theoretical approaches about instant power in power systems, as well as their application techniques in order to compensate harmonics and reactive power by means of AFP. Moreover, this work present new and better application of the theory above mentioned. This new approach consists in the simplification considering the instant active power as a really physical concept and easily measurable. More particularly, it is specially considered, thanks to its simplicity and extra good results, the so called General Theory of Simplified Instant Power (GTSIP). GTSIP is applicable to mono-phase systems as well as three-phase systems with or without neutral line. Prototypes have been built, with analogical and digital control, based on mentioned theories, and experimental results demonstrate the validity of the overall system. An industrial prototype AFP of 40 kVA (compensating power) have been built. Its control is based on GTSIP and experimental results demonstrate the excellent behaviour, even with electronic loads which Total Harmonic Distortion (THD) eceeds 70%. This THD is reduced below 5% by the mentioned AFP
