Design of a Digital PR Controller for Harmonic Compensation of Single-Phase Grid-Tied Inverter with System Parameter Uncertainty

A key part of any DC to AC conversion device is the high frequency filter with the primary objective to eliminate high frequency switching harmonics introduced by the converter switches. So, the design of a properly tuned filter is of utmost importance to ensure proper voltage and current injection into the grid. If the values of the filter components change over time due to environmental factors, the inverter output will degrade. The paper proposes a single-phase grid tied inverter using PR controller in combination with Harmonic Compensator (HC) to eliminate higher order harmonics in the inverter output caused by improper filter design or the filter becoming out of tune over time. The performance of the inverter is examined with and without the HC to determine the effectiveness of the proposed system. The design of the PR controller and the HC is done using MATLAB and testing was performed on a 2 kW IGBT based grid-connected single-phase inverter using dSPACE 1104.