Author : Dasareddy Mohanreddy and Tenapalli Gowri Manohar

Multilevel converters have been introduced as static high-power converters for medium- to high voltage applications such as large electric drives, reactive power compensations, and FACTS devices. The multilevel converters synthesize a desired stepped output voltage waveform by the proper arrangement of the power semiconductor devices from several lower dc voltage sources. The main advantage of multilevel converters is the use of mature medium power semiconductor devices, which operate at reduced voltages. As a result, the switching losses and voltage stress on power electronic devices are reduced. Also, the output voltage has small voltage steps, which results in good power quality, low-harmonic components, and better electromagnetic compatibility. Multilevel converters have obtained more and more attention in recent years and new topologies with a wide variety of control strategies have been developed. Among the multilevel Converters, the cascaded H-bridge topology (CHB) is particularly attractive in high-voltage applications, because it requires the least number of components to synthesize the same number of voltage levels.This paper gives the MATLAB/SIMULINK analysis of three-phase, five-level and seven level cascaded multilevel voltage source inverter based DSTATCOM and active power filter with various PWM techniques for power line conditioning to improve power quality in the power distribution network.

Keywords: PWM technique, Cascaded multilevel voltage source inverter, Cascaded H- Bridge topology , Harmonics, Power quality

Article published in International Journal of Current  Engineering  and Technology, Vol.3,No.2 (June- 2013)