Operation and control of a Dynamic Voltage Restorer using Nine-level Cascaded H-Bridge Converter to Mitigating the voltage sag, swell and flicker in Electric power distribution grids

The design and implementation of multi-level voltage source converter based Dynamic Voltage Restorer (DVR) is dealt with in MATLAB/Simulink. The objective of this study is to stabilize the voltage by compensating the sag, swell and flicker in the electric power distribution grids. Multi-level Cascaded H-Bridge Inverter based DVR is used for Improve the output voltage harmonics spectrum. This work proposes the enhancement of power transfer capability and maintaining unity power factor. Relative Harmonic analysis is also discussed based on the Total Harmonic Distortion (THD%) calculations. Now days the use of sensitive electronic equipment has increase which has lead to power quality problems. The various power quality disturbances are voltage sag, voltage swell, voltage flicker, harmonic, transients and etc. To solve these power quality problems various custom power devices are used. Dynamic Voltage Restorer (DVR) is a custom power device used for the Compensation of voltage sag, swell and flicker. Power quality problem is an occurrence manifested as a non- standard voltage, current or frequency. One of the major problems dealt here is the voltage sag, swell and flicker. Dynamic Voltage Restorer provides a cost effective solution for protection of sensitive loads from voltage sag, swell and flicker; although the applied voltage being sinusoidal. MATLAB/Simulink tool is used for evaluating the performance of the proposed control scheme.

Keywords:

Cascade H-Bridge , DVR , Multi-level Inverter , voltage Flicker , voltage sag , voltage swell