Automatic reactive power compensator: An open loop approach

Abstract

Over the last few years the sudden increase of the use of non-linear loads such as personal computers and TV sets created a Power Factor (PF) problem. Although such loads consume relatively small amount of power, however the large number of these loads resulted on huge distortion in the power quality. One major element of the power quality is the PF. This thesis proposes an automatic PF correction circuit which can generate a leading as well as lagging reactive current which can be used to improve the PF. The proposed circuit consists of two semiconductor switches and two capacitors and an inductor. Such configuration is capable of generating not only variable reactive current, but also with very low distortion compared to other techniques, which usually generate a high distortion reactive current. The proposed compensator is controlled by a microprocessor which generates the required switching pulses. The thesis also covers the protection circuits used to protect the semiconductor switches (MOSFETs) during the turn-on and turn-off times.