A cost effective ac voltage regulator to mitigate voltage sags and dim lamps in street-lighting applications

In this paper the authors propose a cost effective ac voltage regulator able to stabilize the output voltage RMS value in order to dim lamps in street-lighting application and mitigate supply voltage sags. Such converter is a transformer-less ac-ac buck converter designed with only four IGBT and a conventional output low-pass filter. The converter operation is regulated by a feedback controller through the input and output voltage monitoring. A 4-kVA laboratory model of the proposed ac-ac buck converter and controller was designed, built and tested in the laboratory in order to verify the feasibility and confirm the effectiveness in fast controlling the output voltage.