Performance and Stability Analysis of Fractional Order SRF-PLL

A novel fractional-order synchronous reference frame phase-locked loop (FO-SRF-PLL) using fractional-order loop filter (FLF) and/or fractional-order voltage-controlled oscillator (FVCO) is proposed in this paper to enhance the overall system performance. Initially, the performance attributes of the proposed FO-SRF-PLL were examined. It was determined that the addition of two fractional-order parameters to the conventional SRF-PLL, namely, the simultaneous utilization of FLF and FVCO, enables the proposed FO-SRF-PLL to track voltage phase angle and amplitude more swiftly and accurately. Subsequently, the stability of the proposed FO-SRF-PLL system is analyzed by mapping the system’s characteristic equation into the fractional-order domain. The impact of the FO-SRF-PLL parameters, along with the order of FLF and FVCO on the stability of the FO-SRF-PLL system, was elucidated through illustrative examples.