Application of Repetitive Control for Restoration of Periodic Signals Distorted by Nonlinear Measurement Devices

A restoration methodology is developed that removes distortion introduced by linear and nonlinear measurement devices. The method, which is based on a learning control algorithm, is restricted for use on signals that are periodic. The developed technique is demonstrated on a high voltage nonlinear instrument transformer used to measure harmonics in power systems. Simulation results show that the method is stable, robust with respect to modeling errors and additive noise, and converges very quickly.