A Modified Capacitor Current Feedback Active Damping Approach for Grid Connected Converters with an LCL Filter

- Journal title : Journal of Power Electronics
- Volume 15, Issue 5, 2015, pp.1286-1294
- Publisher : The Korean Institute of Power Electronics
- DOI : 10.6113/JPE.2015.15.5.1286

Title & Authors

A Modified Capacitor Current Feedback Active Damping Approach for Grid Connected Converters with an LCL Filter

Wan, Zhiqiang; Xiong, Jian; Lei, Ji; Chen, Chen; Zhang, Kai;

Wan, Zhiqiang; Xiong, Jian; Lei, Ji; Chen, Chen; Zhang, Kai;

Abstract

Capacitor current feedback active damping is extensively used in grid-connected converters with an LCL filter. However, systems tends to become unstable when the digital control delay is taken into account, especially in low switching frequencies. This paper discusses this issue by deriving a discrete model with a digital control delay and by presenting the stable region of an active damping loop from high to low switching frequencies. In order to overcome the disadvantage of capacitor current feedback active damping, this paper proposes a modified approach using grid current and converter current for feedback. This can expand the stable region and provide sufficient active damping whether in high or low switching frequencies. By applying the modified approach, the active damping loop can be simplified from fourth-order into second-order, and the design of the grid current loop can be simplified. The modified approach can work well when the grid impedance varies. Both the active damping performance and the dynamic performance of the current loop are verified by simulations and experimental results.

Keywords

Active damping;Capacitor current feedback;LCL filter;

Language

English

Cited by

References

1.

F. Blaabjerg, R. Teodorescu, M. Liserre, and A. V. Timbus, “Overview of control and grid synchronization for distributed power generation systems,” IEEE Trans. Ind. Electron., Vol. 53, No.5, pp. 1398-1409, Oct. 2006.

2.

K. Jalili and S. Bernet, “Design of LCL filters of active-front-end two-level voltage-source converters,” IEEE Trans. Ind. Electron., Vol. 56, No. 5, pp. 1674-1689, May 2009.

3.

T. C. Y. Wang, Y. Zhihong, S. Gautam, and Y. Xiaoming, "Output filter design for a grid-interconnected three-phase inverter," in Power Electronics Specialist Conference, 2003. PESC '03. 2003 IEEE 34th Annual, Vol. 2, pp. 779-784, 2003.

4.

I. J. Gabe, V. F. Montagner, and H. Pinheiro, “Design and implementation of a robust current controller for VSI connected to the grid through an LCL filter,” IEEE Trans. Power Electron., Vol. 24, No. 6, pp. 1444-1452, Jun. 2009.

5.

C. Wessels, J. Dannehl, and F. W. Fuchs, “Active damping of LCL-filter resonance based on virtual resistor for PWM rectifiers ; stability analysis with different filter parameters,” in Power Electronics Specialists Conference, 2008. PESC 2008. IEEE, pp. 3532-3538, 2008.

6.

J. Kukkola and M. Hinkkanen, “Observer-based state-space current control for a three-phase grid-connected converter equipped with an LCL filter,” IEEE Trans. Ind. Appl., Vol. 50, No.4, pp. 2700-2709, Jul./Aug. 2014.

7.

M. Liserre, A. D. Aquila, and F. Blaabjerg, “Genetic algorithm-based design of the active damping for an LCL-filter three-phase active rectifier,” IEEE Trans. Power Electron., Vol. 19, No. 1, pp. 76-86, Jan. 2004.

8.

X. Wang, F. Blaabjerg and P. Loh, “Grid-current-feedback active damping for LCL resonance in grid-connected voltage source converters,” IEEE Trans. Power Electron.. to be published.

9.

B. Chenlei, R. Xinbo, W. Xuehua, L. Weiwei, P. Donghua, and W. Kailei, “Design of injected grid current regulator and capacitor-current-feedback active-damping for LCL-type grid-connected inverter,” in Energy Conversion Congress and Exposition (ECCE), 2012 IEEE, pp. 579-586, 2012.

10.

M. Wagner, T. Barth, C. Ditmanson, R. Alvarez, and S. Bernet, “Discrete-time optimal active damping of LCL resonance in grid connected converters by proportional capacitor current feedback,” in Energy Conversion Congress and Exposition (ECCE), 2013 IEEE, pp. 721-727, 2013.

11.

W. Sun, X. Wu, P. Dai, and J. Zhou, “An over view of damping methods for three-phase PWM rectifier,” in Industrial Technology, 2008. ICIT 2008. IEEE International Conference on, pp. 1-5, 2008.

12.

Z. Sanbao and D. Czarkowski, “Modeling and digital control of a phase-controlled series-parallel resonant converter,” IEEE Trans. Ind. Electron., Vol. 54, No. 2, pp. 707-715, Apr. 2007.

13.

T. Huu-Phuc, M. F. Rahman, and C. Grantham, “Time delay compensation for a DSP-based current-source converter using observer-predictor controller,” in Power Electronics and Drive Systems, 2007. PEDS '07. 7th International Conference on, Bangkok, pp. 1091-1096, 2007.

14.

T. Nussbaumer, M. L. Heldwein, G. Guanghai, S. D. Round, and J. W. Kolar, “Comparison of prediction techniques to compensate time delays caused by digital control of a three-phase buck-type PWM rectifier system,” IEEE Trans. Ind. Electron., Vol. 55, No. 2, pp. 791-799, Feb. 2008.

15.

T. Yi, C. L. Poh, W. Peng, H. C. Fook, G. Feng, and F. Blaabjerg, "Generalized design of high performance shunt active power filter with output LCL filter," IEEE Trans. Ind. Electron., Vol. 59, No.3, pp. 1443-1452, Mar. 2012.

16.

Z. Guohong, T. W. Rasmussen, M. Lin, and R. Teodorescu, “Design and control of LCL-filter with active damping for active power filter,” in Industrial Electronics (ISIE), 2010 IEEE International Symposium on, pp. 2557-2562, 2010.

17.

S. Parker, B. McGrath, and G. Holmes, “Regions of active damping control for LCL filters,” IEEE Trans. Ind. Appl., Vol. 50, No.1, pp. 424-432, Jan.-Feb. 2014.

18.

J. Dannehl, C. Wessels, and F. W. Fuchs, “Limitations of voltage-oriented PI current control of grid-connected PWM rectifiers with LCL filters,” IEEE Trans. Ind. Electron., Vol. 56, No.2, pp. 380-388, Feb. 2009.

19.

P. W. Lehn and M. R. Irvani, “Discrete time modeling and control of the voltage source converter for improved disturbance rejection,” IEEE Trans. Power Electron., Vol. 14, No.6, pp. 1028-1036, Nov. 1999.

20.

J. Dannehl, F. W. Fuchs, X. F. Th, and P. B. Gersen, “PI state space current control of grid-connected PWM converters with LCL filters,” IEEE Trans. Power Electron., Vol. 25, No.9, pp. 2320-2330, Sep. 2010.

21.

B. Otto, Linear Algebra with Applications, 4th ed. USA: Prentice Hall Publishers, Chap. 1, 2008.