A Method Without Stability Issue for Robust Estimation of Three-Phase Grid Frequency

The grid frequency estimation using a recursive signal or an integrator-based method may suffer from stability issue due to accumulation discretization error. To avoid these shortcomings and also obtain robust of three-phase under unbalanced distorted conditions, this letter proposes demodulation-based without integrator. proposed approach relies on the Clarke transform fixed transport delay-based relatively simple finite-impulse-response filters. It includes open-loop structure, thus unconditionally stable. does not demand real-time evaluation trigonometric inverse function. Moreover, it generates improved accuracy as compared with frequency-locked loop phase-looked loop.