Transient Analysis of an Advanced Static Var Compensator Using Quad-Series Voltage-Source PAM Inverters.

This paper deals with an advanced static var compensator (ASVC) using quad-series voltage-source PAM inverters. The ASVC consists of four three-phase voltage-source inverters with a common dc capacitor and four three-phase transformers, each primary winding of which is connected in series each other. Each inverter outputs a square wave voltage, while the synthesized output voltage of the ASVC has a 24-step wave shape. This results not only in a great reduction of harmonic currents and de voltage ripples but also in less switching and snubbing losses.In this paper, transient analysis is performed with the focus on the response of reactive power and the resonance between the dc capacitor and ac reactors. Experimental results obtained from a small-rated laboratory model of 10kVA are also shown to verify analytical results based on the p-q transformation. The analytical results help us to design system parameters such as the capacity of the dc capacitor and feedback gains.