Comparative Study between Two Topologies of an UPQC Six-Leg and an UPQC Seven-Legfull text in English

摘要

UPQC is the powerful tool to settle the power quality problems. UPQC consist of combined series activepower filter (SAPF) that compensates voltage harmonics, voltage sags and voltage swells and parallel activepower filter (PAPF) that compensates harmonics current and reactive current. A three-phase four-wire PAPFhas also another important function. It’s able to compensate the neutral current when the load isunbalanced. In facts there are two important topologies for this PAPF that the first one consist to connectthe neutral wire into the split DC link, however the second one consist to add another leg. In this paper, twoUPQC’s topologies are compared. In the UPQC six-leg, the neutral wire is connected into the split DC link. Forthe UPQC seven-leg the neutral wire is connected into the seventh leg. In addition to well illustrate thedifference between these topologies we were test them in two cases. In the first case (Test 1), the loadpower is supposed lower than the load power in the second case (Test 2). When the power consumed by theload is relatively high, the UPQC seven-leg gives good results compared by the UPQC six-leg.