Performance Investigation of Asymmetrical Cascaded H-Bridge Multilevel Inverter Based Dstatcom in Distribution Network

Abstract

Asymmetrical cascaded H-bridge multilevel inverter based on the series connection of single-phase inverter has the ability to resolve the power quality issues such as elimination in harmonic contents when used with DSTATCOM in the distribution network. By using many separate dc sources, it can produce high number of ac voltage levels. Asymmetrical multilevel inverters are well-suited for high power and medium applications due to their several advantages. In this work, firstly a comparison is done between the different voltage levels (7, 9, 11 and 13) of Asymmetrical cascaded H-bridge multilevel inverter on the basis of T.H.D. After that, performance of seven level asymmetrical cascaded H-bridge inverter based DSTATCOM in the 11 kV/ 400V secondary distribution network is emphasized. The work focusses on the mitigation of harmonics and compensation of load balance during disturbances in the distribution system. Level Shifted Alternate Phase Opposition Disposition PWM control strategy is used for the generation of all the gate pulses. For the generation of reference source currents for DSTATCOM, Synchronous Reference Frame (SRF) theory based on Park’s transformation is employed.