Stability Analysis of Grid-Connected Inverter in Weak Grid Systems

Abstract:

Distributed Generation may be located far away from load centers due to their use of new energy resource distribution characteristics. In this case, Long distance transmission lines will introduce an equivalent impedance to the grid, so that the grid showing the characteristics of a weak grid. In this paper, the interaction between grid-connected inverter and weak grid is studied by means of impedance analysis in the frequency domain. The experimental results are used to evaluate the stability of grid-connected inverter under different grid impedance condition. In a weak grid system, the increasing grid inductance results in a smaller stability margin of impedances ration. To improve the stability of the grid-connected inverter, the paper introduces a kind of active damping method with a virtual resistor in parallel with the capacitor. The new active damping control scheme without differential factor has a simple algorithm. The experimental results are depicted to demonstrate the correctness of theoretical analysis and the feasibility of the active damping algorithm.

• Periodical: Advanced Materials Research (Volumes 614-615)
• Pages: 1514-1518
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.614-615.1514
• Online since: December 2012
• Authors: Xin Chen, Chun Yin Gong, Lin Cheng
• Keywords: Active Damping Algorithm, Grid-Connected Inverter, Stability, Weak Grid

References

[1] M. Reza, D. Sudarmadi, F.A. Viawan, and etc. Dynamic stability of power systems with power electronic interfaced DG (Atlanta USA, IEEE PESC'06, November 2006).

DOI: 10.1109/psce.2006.296510

[2] S. Yang, Q. Lei, Fang Z. Peng, Zhaoming Qian, A robust control scheme for grid-connected voltage source inverters (C.A. USA, IEEE APEC 2010, February 2010).

DOI: 10.1109/apec.2010.5433380

[3] T. Midtsund, J. A. Suul, T. Undel, Evaluation of current controller performance and stability for voltage source converters connected to a weak grid (Kolkata India, IEEE Power India Conference, 2010).

DOI: 10.1109/pedg.2010.5545794

[4] X. Chen and J. Sun, A study of renewable energy system harmonic resonance based on a DG test-bed (IEEE 2011 Applied Power Electronics Conference, March 2011).

DOI: 10.1109/apec.2011.5744716

[5] J. Sun, Impedance-based stability criterion for grid-connected inverters, IEEE Transactions on Power Electronics, Vol. 26, No. 11, pp.3075-3078, 2011.

DOI: 10.1109/tpel.2011.2136439

[6] X. Chen and J. Sun, Characterization of inverter-grid interactions using a hardware-in-the-loop system test-bed (Jeju, Korea, IEEE ECCE Asia, 2011).

DOI: 10.1109/icpe.2011.5944412

[7] M. Cespedes and J. Sun, Renewable Energy Systems Instability Involving Grid-Parallel Inverters (IEEE 2009 Applied Power Electronics Conference, March 2010).

DOI: 10.1109/apec.2009.4802943