Mathematical models of a three-level advanced static VAr compensator

Two mathematical models of an advanced static VAr compensator (ASVC) are described. One model was obtained using time-domain analysis of the ASVC circuit and then developed into an s-domain model which was used to study the compensator´s control system. Both models were validated using a three phase, 4 kVAr hardware model of a three-level ASVC. The time-domain model was also validated using computer simulations carried out with the EMTDC program. Two switching strategies were considered in the study: fundamental frequency modulation (FFM) and selective harmonic modulation (SHEM). The time domain model was used to predict the waveforms at various parts of the ASVC circuit, for both switching strategies