An Enhanced CDSC-Based Grid Parameter Estimation Method for Distorted Grids

In modern power systems, DC offset and odd-order harmonics degrade grid phase and frequency estimation accuracy. To address this problem, this paper proposes an enhanced grid parameter estimation scheme based on cascaded delayed signal cancellation (CDSC). Unlike the conventional CDSC, the proposed method introduces a redesigned delay configuration, significantly reducing the inherent filtering delay while preserving the rejection capability for the DC component and targeted odd-order harmonics. Meanwhile, an amplitude-phase compensation strategy is developed to correct the magnitude attenuation and phase distortion introduced by the CDSC filter, which allows accurate extraction of the fundamental grid component. Furthermore, a frequency-adaptive module is integrated to maintain stable grid synchronization under off-nominal frequency deviations. Finally, experimental results verify the effectiveness of the proposed method.