Jong-Hyun Lee, Hae-Gwang Jeong, and Kyo-Beum Lee, “Performance Improvement of Grid-Connected Inverter Systems under Unbalanced and Distorted Grid Voltage by Using a PR Controller,” Journal of Electrical Engineering & Technology, vol. 7, no. 6, pp. 918–925 > Paper

This paper proposes a control method for grid-connected inverter systems under unbalanced and distorted grid voltage. The

proposed method can reduce the power ripple caused by the unbalanced condition and compensate for the low-order harmonics

of the output currents caused by the distortion of grid voltage. To reduce the power ripple, our method replaces the two

conventional PI controllers with one PR controllers in the stationary frame. PR controllers can implement selective harmonic

compensation without excessive computational requirements; the use of these controllers simplifies the method. Both the simulated

and experimental results agree well with the theoretical analysis.