A Unified Control Strategy for Three-Phase Inverter in Distributed Generation
K. Narsaiah1, T. Srinivas2
1Narsaiah Kundhuri, Department of Electrical and Electronic Engineering, JNT University Hyderabad, Telangana. India.
2T. Srinivas, Assistant Professor, Department of Electrical and Electronic Engineering, Siddhartha Institute of Engineering & Technology, Hyderabad, Telangana. India.
Manuscript received on August 26, 2015. | Revised Manuscript received on August 31, 2015. | Manuscript published on September 15, 2015. | PP: 1-5 | Volume-3 Issue-10, September 2015. | Retrieval Number: J09310931015/2015©BEIESP
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© The Authors. Published By: Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)

Abstract: This project presents a unified control strategy that enables both islanded and grid-tied operations of three-phase inverter in distributed generation, with no need for switching between two corresponding controllers or critical islanding detection. The proposed control strategy composes of an inner inductor current loop, and a novel voltage loop in the synchronous reference frame. The inverter is regulated as a current source just by the inner inductor current loop in grid-tied operation, and the voltage controller is automatically activated to regulate the load voltage upon the occurrence of islanding. Furthermore, the waveforms of the grid current in the grid-tied mode and the load voltage in the islanding mode are distorted under nonlinear local load with the conventional strategy. Finally, the effectiveness of the proposed control strategy is validated by the simulation and experimental results.
Keywords: Distributed generation (DG), islanding mode, load current, seamless transfer, three-phase inverter, unified control strategy.