Fuzzy logic control of a dynamic voltage restorer

Dynamic voltage restorer can provide the most cost effective solution to mitigate voltage sags by establishing the proper voltage quality level that is required by customer. This device is connected in series with the distribution feeder at medium voltage. A fuzzy logic control is proposed. As is known, the PWM converter is actually non-linear, but the PI is a linear controller, so it can only guarantee the stability of this converter in a local area. Simulation results are shown to validate these control methods.