GholamAli Heydari - Shahid Bahonar University of Kerman – Electrical Eng. Dept.R&D Center, Iran Khodro CompanyIran
Mohsen Mohammadian - Shahid Bahonar University of Kerman – Electrical Eng. Dept.R&D Center, Iran Khodro CompanyIran

Flexible AC Transmission Systems arevery useful utilities in electric power management. One of qualification factors of these instruments is the amplitude of highfrequency harmonics produced in their output. Most of recent types of FACTS use a main building block called VSC (Voltage Source Converter) which convert DC to AC bymodulating AC wave forms on DC by using pulse modulation. Hysteresis modulation is a simple and useful technique for this kind of purpose. Changing the hysteresis band dynamically can help to attenuate output harmonics. In this article a TSK fuzzy controller has been designed in order to vary the proposed band according to system signals to reach suitable results. In addition an integrator has been added to modulator's loop for employing integral control advantages.

Variable Band Width Hysteresis, Fuzzy Algorithm, FACTS, VSC, TSK