Performance and analysis for improvement of power quality and voltage sag mitigation

Abstract: Aiming further to reduce its switching losses, an appropriate discontinuous modulation scheme is proposed and studied here in detail to doubly ensure that maxi-mal reduction of commutations is achieved. With an appropriately designed control scheme had incorporated with nine-switch converter is shown to favorably raise the overall power quality and voltage mitigation hence justifying its role as a power conditioner at a reduced semiconductor cost. A nine- switch power converter having two sets of out-put terminals was recently proposed in addition of the traditional back- to-back power converter that uses 12 switches in total. The nine-switch converter had already been proven to have certain advantages, in addition to its component saving topological features. Despite these advantages, the nine-switch converter has so requiring an oversized dc-link capacitor, limited amplitude sharing, and constrained phase shift between its two sets of output terminals. Instead of accepting these tradeoffs as limitations, a nine-switch power conditioner is proposed here that virtually ―converts‖ most of these topological shortfalls are overcome into interesting performance advantages.

Keywords: voltage sag, mitigation, pulse-width modulation, nine-switch converter, power conditioner, power quality.