Stability of photovoltaic and wind turbine grid-connected inverters for a large set of grid impedance values

The aim of this paper is to analyze the stability problems of grid connected inverters used in distributed generation. Complex controllers (e.g., multiple rotating dq-frames or resonant-based) are often required to compensate low frequency grid voltage background distortion and an LCL-filter is usually adopted for the high frequency one. The possible wide range of grid impedance values (distributed generation is suited for remote areas with radial distribution plants) challenge the stability and the effectiveness of the LCL-filter-based current controlled system. It has been found out and it will be demonstrated in this paper that the use of active damping helps to stabilise the system in respect to many different kinds of resonances. The use of active damping results in an easy plug-in feature of the generation system in a vast range of grid conditions and in a more flexible operation of the overall system able to manage sudden grid changes. In the paper, a vast measurement campaign made on a single-phase system and on a three-phase system used as scale prototypes for photovoltaic and wind turbines, respectively, validate the analysis.

[1]  P.J.M. Heskes,et al.  Harmonic interaction between a large number of distributed power inverters and the distribution network , 2004, IEEE Transactions on Power Electronics.

[2]  P. Lundsager,et al.  Integration of wind power in the power system , 2002, IEEE 2002 28th Annual Conference of the Industrial Electronics Society. IECON 02.

[3]  F. Blaabjerg,et al.  Power electronics as efficient interface in dispersed power generation systems , 2004, IEEE Transactions on Power Electronics.

[4]  Robert W. Erickson,et al.  Fundamentals of Power Electronics , 2001 .

[5]  V. Blasko,et al.  A novel control to actively damp resonance in input LC filter of a three-phase voltage source converter , 1997 .

[6]  V. Blasko,et al.  A novel control to actively damp resonance in input LC filter of a three phase voltage source converter , 1996, Proceedings of Applied Power Electronics Conference. APEC '96.

[7]  Frede Blaabjerg,et al.  Step-by-step design procedure for a grid-connected three-phase PWM voltage source converter , 2004 .

[8]  L. J. Borle,et al.  A combined voltage controlled and current controlled "dual converter" for a weak grid connected photovoltaic system with battery energy storage , 2002, 2002 IEEE 33rd Annual IEEE Power Electronics Specialists Conference. Proceedings (Cat. No.02CH37289).

[9]  M. Liserre,et al.  Genetic algorithm based design of the active damping for a LCL-filter three-phase active rectifier , 2004, Eighteenth Annual IEEE Applied Power Electronics Conference and Exposition, 2003. APEC '03..

[10]  M. Liserre,et al.  Stability improvements of an LCL-filter based three-phase active rectifier , 2002, 2002 IEEE 33rd Annual IEEE Power Electronics Specialists Conference. Proceedings (Cat. No.02CH37289).

[11]  M. Liserre,et al.  Design and control of an LCL-filter based three-phase active rectifier , 2001, Conference Record of the 2001 IEEE Industry Applications Conference. 36th IAS Annual Meeting (Cat. No.01CH37248).

[12]  K. Uhlen,et al.  Wind turbines in weak grids-constraints and solutions , 2001 .

[13]  Frede Blaabjerg,et al.  Control in Power Electronics , 2002 .

[14]  Lennart Söder,et al.  Comparison of International Regulations for Connection of Wind Turbines to the Network , 2004 .

[15]  Gerard Ledwich,et al.  Connection of inverters to a weak grid , 2000, 2000 IEEE 31st Annual Power Electronics Specialists Conference. Conference Proceedings (Cat. No.00CH37018).

[16]  Vassilios G. Agelidis,et al.  Inverters for single-phase grid connected photovoltaic systems-an overview , 2002, 2002 IEEE 33rd Annual IEEE Power Electronics Specialists Conference. Proceedings (Cat. No.02CH37289).

[17]  Donald Grahame Holmes,et al.  Stationary frame current regulation of PWM inverters with zero steady state error , 1999, 30th Annual IEEE Power Electronics Specialists Conference. Record. (Cat. No.99CH36321).

[18]  K. Uhlen,et al.  Large-scale wind power integration and voltage stability limits in regional networks , 2002, IEEE Power Engineering Society Summer Meeting,.

[19]  Frede Blaabjerg,et al.  Power Converters and Control of Renewable Energy Systems , 2004 .