High Efficiency SVG System using Open-Winding Transformer and Two Space Vector Modulated Inverters

The static var generator (SVG) is practically used for supplying reactive power to power system. The purpose of using SVG is to maintain power system stability and enable to control power flow freely. In a general SVG system, a multiple inverter or a PWM (pulse width modulation) inverter with high carrier frequency is usually used in order to reduce the low-order harmonic. However, a multiple inverter has a problem of complex configuration of transformer and a PWM inverter with high carrier frequency has a problem of high switching losses. In this paper, in order to overcome these problems, we propose a new high efficiency SVG system which uses an open-winding transformer and two space vector modulated inverters. Concretely, this proposed new SVG system consists of a low switching frequency 3-level inverter and a high switching frequency 2-level inverter, connected respectively to either side of the terminals of the open-winding transformer. As a result, by using this proposed system, good inverter efficiency of the SVG can be realized and also the harmonic components of the output current waveforms can be reduced, we were able to obtain good results, so we will present this system here