Design of robust and frequency adaptive controllers for harmonic disturbance rejection in a single-phase power network

This paper deals with the control of a voltage source inverter which rejects the harmonic disturbances in a power network. Two controllers are studied : the first one uses the method of the internal model of Morari whereas the second one is based on the pole placement principle. But the closed-loop system is very sensitive to slight changes of the network frequency. As this latter one can vary in a small interval, the controllers are adapted to the fundamental frequency tracked by an extended Kalman filtering. We prove that the regulator made of the frequency estimator and the adapted controller based on the implicit pole assignment is stable. Finally, the robustness to uncertainties of parameter system and the adaptability to the frequency variations have been shown by simulations.