A High-Precision Discrete Tracking Differentiator and Its Application in Processing PMU Data

A new and simple tracking differentiator (TD) with high precision based on discrete time optimal control (DTOC) law is proposed. The DTOC law is constructed in the form of the state feedback for a discrete-time double-integral system by using the state back-stepping approach. Zero-order hold of the control signal is introduced to improve the precision of discretization model. The control signal sequence in this approach is determined by the linearized criterion according to the position of the initial state point on the phase plane. The state estimation filtering characteristics of the TD are analyzed. The field phasor measurement units (PMUs) data are processed using the proposed TD. Not requiring complex power system modeling and historical data, the proposed TD is suitable for real-time synchrophasor estimation application especially when the states are corrupted by noise.