Harmonic Reduction Technique Using Flying Capacitor Based Z Source Inverter For A Dvr

The dynamic voltage restorer (dvr) is a commercially available, popular device to eliminate voltage sags and swells in the distribution lines. its basic function is to inject the voltage difference (difference between the pre-sag and sag voltage) to the power line and maintains the pre-sag voltage condition in the load side. the efficiency of the dvr depends on the performance of the efficiency control technique involved in switching the inverters. z-source inverters are recent topological options proposed for buck–boost energy conversion with a number of possible voltage- and current-type circuitries. common feature noted is their inclusion of an lc impedance network, placed between the dc input source and inverter bridge. this impedance network allows the output end of a voltage-type z-source inverter to be shorted for voltage boosting without causing a large current flow and the terminal current of a current-type inverter to be interrupted for current boosting without introducing over voltage oscillations to the system. therefore, z-source inverters are, in effect, safer and less complex and can be implemented using only passive elements with no additional active semiconductor needed. this paper presents a selective harmonic elimination using flying capacitor connection in z-source inverter. closed loop control for a simple system is modeled and simulated using matlab software. the simulation results are presented to demonstrate the effectiveness of the proposed dvr system.