摘要
Accurate and prompt estimation of phase angles, frequency, and magnitudes of the grid voltage is extremely important in paving a good platform for a fast and reliable operation of power grid monitoring, protection, and control. The phase-locked loop (PLL) served this purpose for decades while the concept of the frequency-locked loop (FLL) has been proposed more recently. Even though FLL and PLL share some similarities, some differences still exist. Further research on FLLs can boost their capabilities and open up new windows in designing devices for grid synchronization. MDSC filters are peculiar system of filters. Their applications to FLLs can enrich FLL&null performance. This paper focuses on applying the stationary reference frame MDSC filters at In-loop and pre-filtering stages of FLL and compares its effectiveness with widely used Cascaded Multiple Delayed Signal Cancellation (CDSC) and Complex Band Pass Filter (CBF) based filtering techniques. The application of K-factor methodology based controller design to FLLs has also been explored for dynamic performance enhancements. A new Cascaded Multiple Delayed Signal Cancellation (CMDSC) filter is proposed and is compared with its CDSC counterpart proposed earlier in literature to address the DC offsets and imbalances effects under adverse grid conditions. The effectiveness of the proposed method is verified through OPAL-RT real time simulations and dSPACE ds1104 and TMS320F28335 micro-controller experimental test bench.