Multi-channel synchronous reference frame PLL based on feedback structure

This paper presents a multi-channel synchronous reference frame PLL based on feedback structure, which is called MSRF-PLL. The proposed method is based on the feedback structure in synchronous reference frame. Positive- and negative-sequence components at fundamental frequency are extracted accurately even with harmonics in grid voltage. The structure is quite simple because no complex decoupling networks between each channel are required. Moreover, both dq components and αβ components are generated in MSRF-PLL which makes it suitable for current and power control in either stationary frame or synchronous frame. In this paper, mathematical derivations of MSRF-PLL structure are presented. Also the validity of MSRF-PLL is verified by both simulations and Experiments results.