A Control Algorithm Based on the Conservative Power Theory for Cooperative Sharing of Imbalances in Four-Wire Systems

• Published in: IEEE transactions on power electronics Vol. 34; no. 6; pp. 5325 - 5339
• Main Authors: Burgos-Mellado, Claudio, Cardenas, Roberto, Saez, Doris, Costabeber, Alessandro, Sumner, Mark
• Format: Journal Article
• Language: English
• Published: New York IEEE 01.06.2019; The Institute of Electrical and Electronics Engineers, Inc. (IEEE)
• Subjects: Algorithms; conservative power theory (CPT); Control algorithms; Control systems; Control theory; Cooperative control; Cooperative imbalance sharing; Distributed generation; droop control; four-wire microgrids (MGs); Harmonic analysis; Harmonic distortion; Inverters; Loops; Microgrids; Voltage control; Voltage measurement; Wire; Wires
• ISSN: 0885-8993; 1941-0107; 1941-0107
• DOI: 10.1109/TPEL.2018.2869866

A cooperative control scheme based on the conservative power theory (CPT) is proposed, which can share imbalances in three-phase four-wire droop-controlled systems. By utilizing the CPT, the balanced, unbalanced, and distorted components of the currents and powers in a microgrid can be identified. Using control loops based on virtual impedances and implemented in the stationary a-b-c frame, the imbalances and harmonics are shared between the different four-leg inverters in the microgrid. A secondary control loop is implemented to regulate the maximum voltage imbalance/distortion at the point of common coupling or any other point in the microgrid. The theoretical background of the method is presented, and experimental validation is demonstrated using a laboratory-scale microgrid with two inverters operating at 5 kW.