Hybrid Adaptive/Nonadaptive Delayed Signal Cancellation-Based Phase-Locked Loop

To improve the disturbance rejection capability of phase-locked loops (PLLs), which are undoubtedly the most common synchronization tool in power and energy applications, using different filtering techniques have been suggested in the literature. Among these filtering strategies, the delayed signal cancellation (DSC) operator is highly popular probably because it can be easily tailored for different grid scenarios. The DSC operator(s) can be used either as an in-loop filter in the PLL structure or as a preprocessing filter before the PLL input. The latter case is often preferred mainly because it results in a faster dynamic response in the extraction of grid voltage parameters. In this paper, a combination of an adaptive DSC operator with multiple nonadaptive DSC operators is suggested as the PLL preprocessing stage. To compensate for the phase and amplitude errors caused by the nonadaptive operators, a compensator is designed and cascaded with them. The proposed filter requires a low computational burden for the implementation and ensures a fast dynamic response and high filtering capability for the PLL. The effectiveness of this technique is verified through experimental results.