A study of bidirectional active and reactive power exchange and of the harmonic distortion in GTO thyristors rectifiers

The high power AC-DC thyristor converters highly disturb the AC supply source. They necessarily consume reactive power and their power factor becomes poorer as the DC output voltage decreases. Furthermore they generate a big amount of current harmonics on the AC line. This harmonic disturbance is all the more important as the line short circuit power has a small value. The usual efficient solution is the use of costly and bulky harmonic filters or reactive power compensator. The authors propose a force-commutated converter structure in order to solve these problems. This set-up allows an independent control of active and reactive power exchange between AC line and DC load, as well as the control of harmonic distortion of AC variables. They consider the operating principle of the converter and discuss the results of numerical simulation. They compare this converter with a conventional converter