Performance Analysis of Various Multi-Level Voltage Source Converter Topologies

Abstract

Multi-Level Inverter is a boon to power industries in the present scenario as power industries require high voltage and good quality sinusoidal voltage waveform. Both these requirements can be fulfilled by Multi-Level Inverter. But the proper selection of inverter for different industrial application is necessary. Here the selection of Voltage Source Multi-Level Inverter for STATCOM (Static Compensator) is carried out by performing simulation based performance analysis. STATCOM is a FACTS (flexible alternating current transmission system) device which is used to maintain flat voltage profile while providing reactive power support and damp power oscillations. STATCOM is connected to the transmission line and it works on high voltage ranging from 132kV to 765kV. Hence, conventional two -level inverter is not a good choice as it has to operate in PWM mode and there is a requirement of large transformers. In high power and high voltage application PWM causes high switching losses, therefore, soft switching at the fundamental frequency is desired. The STATCOM discussed here is having constant dc-link voltage which is not found in conventional STATCOM operation. Maintaining constant dc-link voltage helps in utilizing converter efficiently. The STATCOM performance is analyzed by switching inductive and capacitive load for a particular duration in MATLAB/SimPowerSystem Toolbox.