Droop Control Method with Virtual Output Impedance for Parallel Operation of Uninterruptible Power Supply Systems in a Microgrid

In this paper, a novel droop control scheme applied to distributed UPSs forming a microgrid is proposed. The control architecture consists of two levels of hierarchy: 1) the P/Q droop control method of every UPS unit and 2) the management of the microgrid through the control of the setpoints of the units and the intelligent switch connected to the strong grid. This second level of control let us to connect or disconnect the microgrid to the utility mains, resulting in two scenarios: grid-connected and islanding operation mode. Also, it is taken into account the seamlessly transition between both operation modes, the possibility to share power with the utility grid, and the energy management of the overall system.

[1]  S. Bacha,et al.  Real-Time Analysis of the Control Structure and Management Functions of a Hybrid Microgrid System , 2006, IECON 2006 - 32nd Annual Conference on IEEE Industrial Electronics.

[2]  A. Keyhani,et al.  Control of distributed generation systems - Part II: Load sharing control , 2004, IEEE Transactions on Power Electronics.

[3]  A.L. Dimeas,et al.  Operation of a multiagent system for microgrid control , 2005, IEEE Transactions on Power Systems.

[4]  Kari Alanne,et al.  Distributed energy generation and sustainable development , 2006 .

[5]  Arthur R. Bergen,et al.  Power Systems Analysis , 1986 .

[6]  J. Miret,et al.  A wireless controller to enhance dynamic performance of parallel inverters in distributed generation systems , 2004, IEEE Transactions on Power Electronics.

[7]  P.L. Villenueve,et al.  Concerns generated by islanding [electric power generation] , 2004, IEEE Power and Energy Magazine.

[8]  N. Yorino,et al.  An interaction problem of distributed generators installed in a MicroGrid , 2004, 2004 IEEE International Conference on Electric Utility Deregulation, Restructuring and Power Technologies. Proceedings.

[9]  J.A.P. Lopes,et al.  Defining control strategies for MicroGrids islanded operation , 2006, IEEE Transactions on Power Systems.

[10]  Josep M. Guerrero,et al.  Wireless-control strategy for parallel operation of distributed generation inverters , 2006, Proceedings of the IEEE International Symposium on Industrial Electronics, 2005. ISIE 2005..

[11]  N. D. Hatziargyriou,et al.  Micro-Grid Simulation during Grid-Connected and Islanded Modes of Operation , 2005 .

[12]  Massimo Ceraolo,et al.  Control techniques of Dispersed Generators to improve the continuity of electricity supply , 2002, 2002 IEEE Power Engineering Society Winter Meeting. Conference Proceedings (Cat. No.02CH37309).

[13]  J. Miret,et al.  Decentralized Control for Parallel Operation of Distributed Generation Inverters in Microgrids Using Resistive Output Impedance , 2006, IECON 2006 - 32nd Annual Conference on IEEE Industrial Electronics.

[14]  Deepak Divan,et al.  Novel architectures and control for distributed UPS systems , 1994, Proceedings of 1994 IEEE Applied Power Electronics Conference and Exposition - ASPEC'94.

[15]  R. Adapa,et al.  Control of parallel connected inverters in stand-alone AC supply systems , 1991, Conference Record of the 1991 IEEE Industry Applications Society Annual Meeting.

[16]  Timothy C. Green,et al.  High-Quality Power Generation Through Distributed Control of a Power Park Microgrid , 2006, IEEE Transactions on Industrial Electronics.

[17]  Hua Jin,et al.  Control of parallel inverters in distributed AC power systems with consideration of line impedance effect , 2000 .

[18]  Chih-Chiang Hua,et al.  Parallel operation of inverters for distributed photovoltaic power supply system , 2002, 2002 IEEE 33rd Annual IEEE Power Electronics Specialists Conference. Proceedings (Cat. No.02CH37289).

[19]  Josep M. Guerrero,et al.  Output impedance design of parallel-connected UPS inverters with wireless load-sharing control , 2005, IEEE Transactions on Industrial Electronics.