Synchronous double reference frame PLL applied to a unified power quality conditioner

This paper presents a positive sequence voltage detector based on a new "synchronous double reference frame PLL" (SDRF-PLL). This PLL exhibits a fast, precise and robust behavior under unbalanced utility conditions. When amplitude and phase of the positive sequence source voltage are known, various compensation strategies are feasible for the control of the unified power quality conditioner. Four suitable control strategies are shown. The performance of the proposed SDRF-PLL is verified by means of its application in the control of a unified power quality conditioner. In this paper, an analytical study and a verification by simulation are conducted.