Skip to main content

Advertisement

SpringerLink
Log in

Reducing neutral-point voltage fluctuation in NPC three-level active power filters

  • Original Paper
  • Published:
Electrical Engineering Aims and scope Submit manuscript

Abstract

Shunt active power filters (SAPFs) have been widely used to improve power quality of the grid by mitigating harmonics injected from nonlinear loads. This paper presents a new method for improving the performance of SAPFs using neutral-point-clamped (NPC) three-level inverters. NPC three-level inverters often suffer excessive voltage fluctuations at the neutral-point of DC-link capacitors, which may damage switching devices and cause additional high harmonic distortion of the output voltage. In order to solve the problem, two compensating schemes are proposed to restrict voltage fluctuation in the inverters. The first is voltage dependent, adopting a voltage compensation method, while the second is current dependent, using a current compensation method. The paper describes the respective circuit architectures and principles of operation. Corresponding models are mathematically formulated and evaluated under typical balanced and unbalanced working load conditions. The results show that both schemes are able to alleviate considerably voltage oscillations and hence harmonic distortions, and the current-compensated NPC inverter outperforms the voltage-compensated NPC inverter. Consequently, it is shown that the proposed approaches are effective and feasible for improving power quality of the grid when connected to nonlinear loads.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7
Fig. 8
Fig. 9
Fig. 10
Fig. 11
Fig. 12
Fig. 13
Fig. 14
Fig. 15

Similar content being viewed by others

Abbreviations

SAPF:

Shunt active power filters

NPC:

Neutral point clamped

DG:

Distributed generation

PV:

Photovoltaics

THD:

Total harmonic distortion

SVPWM:

Space voltage vector pulse-width modulation

VNPCI:

Voltage-dependent NPC three-level inverter

CNPCI:

Current-controlled NPC three-level inverter

IGBT:

Insulated gate bipolar transistor

\(u_\mathrm{sa}, u_\mathrm{sb}, u_\mathrm{sc}\) :

Three-phase alternating-current supply

\(i_\mathrm{sa}, i_\mathrm{sb}, i_\mathrm{sc}\) :

Grid currents

\(i_\mathrm{La}, i_\mathrm{Lb}, i_\mathrm{Lc}\) :

Load currents

\(i_\mathrm{ca}, i_\mathrm{cb}, i_\mathrm{cc}\) :

Compensation currents provided by the SAPF

\(u_\mathrm{o}\) :

Neutral-point voltage of the three-phase bridge arm

\(u_\mathrm{N}\) :

Neutral-point voltage of the DC-link capacitors

\(u_\mathrm{c}\) :

Voltage of the primary side of the transformer

\(u_\mathrm{b}\) :

Compensating voltage

\(u_\mathrm{s}\) :

DC-link voltage applied across the capacitors

\(S_{1}, S_{2}, S_{3}, S_{4}\) :

IGBT power switches

T :

Coupling transformer

L, \({C}_{f}\) :

LC filter

\(u_\mathrm{dc}\) :

DC voltage applied to the single-phase full-bridge inverter

\(u_{i}\) :

Voltage output of the single-phase inverter

\(i_{1}\) :

Current through the filter inductor

\(i_{2}\) :

Transformer primary side current

\(i_\mathrm{cf}\) :

Current through the filter capacitor

\({D}_{1}\) :

Diode used to prevent reverse current flow

\({L}_{2}, {C}_{3}\) :

LC filter

\(u_\mathrm{dc1}\) :

Voltage input of the boost DC/DC converter

\(u_\mathrm{dc2}\) :

Voltage output of the boost DC/DC convertor

\(i_{\mathrm{c3(off})}\) :

Current in capacitor \({C}_{3}\) when switching device \({S}_{5}\) is turned off

\(i_{3}\) :

Current in the inductor \({L}_{1}\)

\(i_{4}\) :

Compensating current

\(u_{\mathrm{L1(off})}\) :

Voltage across the inductor \({L}_{1}\) when switching device \({S}_{5}\) is turned off

\(u_{\mathrm{L1(on})}\) :

Voltage across inductor \({L}_{1}\) when switch \({S}_{5}\) is turned on

D :

Duty cycle of the switching device \({S}_{5}\)

\(K_{p}, K_{i}\) :

Parameters of the PI controller

References

  1. Pepermans G, Driesen J, Haeseldonckx D, Belmans R, D’haeseleer W (2005) Distributed generation: definition, benefits and issues. Energy Policy 33:787–798

    Article  Google Scholar 

  2. Pouresmaeil E, Montesinos-Miracle D, Gomis-Bellmunt O, Sudrià-Andreu A (2011) Instantaneous active and reactive current control technique of shunt active power filter based on the three-level NPC inverter. Int Trans Electric Energy Syst 21:2007–2022

    Google Scholar 

  3. Allmeling JH (2004) A control structure for fast harmonics compensation in active filters. IEEE Trans Power Electron 19(2):508–514

    Article  Google Scholar 

  4. Liang W, Donglai Z, Yi W, Bin W, Hussain SA (2016) Power and voltage balance control of a novel three-phase solid-state transformer using multilevel cascaded H-bridge inverters for microgrid applications. IEEE Trans Power Electron 31(4):3289–3301

    Article  Google Scholar 

  5. Roodsari BN, Nowicki EP (2013) Fast space vector modulation algorithm for multilevel inverters and its extension for operation of the cascaded H-bridge inverter with non-constant DC sources. IET Power Electron 6:1288–1298

    Article  Google Scholar 

  6. Ke M, Frede B (2012) The impact of power switching devices on the thermal performance of a 10 MW wind power NPC converter. Energies 5(7):2559–2577

    Article  Google Scholar 

  7. Muyeen SM, Takahashi R, Tamura J (2010) Wind power and hydrogen generation system with cooperatively controlled three-level NPC-VSC based energy capacitor. Int Trans Electric Energy Syst 20:1071–1081

    Google Scholar 

  8. Zaveri T, Bhalja BR, Zaveri N (2012) Load compensation using DSTATCOM in three-phase, three-wire distribution system under various source voltage and delta connected load conditions. Int J Electric Power Energy Syst 41:34–43

    Article  Google Scholar 

  9. Saad S, Zellouma L (2009) Fuzzy logic controller for three-level shunt active filter compensating harmonics and reactive power. Electric Power Syst Res 79:1337–1341

    Article  Google Scholar 

  10. Celanovic N, Boroyevich D (2000) A comprehensive study of neutral-point voltage balancing problem in three-level neutral-point-clamped voltage source PWM inverters. IEEE Trans Power Electron 15:242–249

    Article  Google Scholar 

  11. Ui-Min C, Frede B, Kyo-Beum L (2015) Method to minimize the low-frequency neutral-point voltage oscillations with time-offset injection for neutral-point-clamped inverters. IEEE Trans Ind Appl 51:1678–1691

    Article  Google Scholar 

  12. Rodriguez J, Bernet S (2010) A survey on neutral-point-clamped inverters. IEEE Trans Ind Electron 57:2219–2230

    Article  Google Scholar 

  13. Helle L, Nielsen SM, Enjeti P (2002) Generalized discontinuous DC-link balancing modulation strategy for three-level inverters. In: Power conversion conference, Osaka, Japan, vol 2, pp 359–366

  14. Yazdani A, Iravani R (2005) Generalized state-space averaged model of the three-level NPC converter for systematic DC-voltage-balancer and current-controller design. IEEE Trans Power Deliv 20:1105–1114

    Article  Google Scholar 

  15. Zaragoza J, Pou J, Ceballos S, Robles E, Jaen C (2009) Voltage-balance compensator for a carrier-based modulation in the neutral-point-clamped converter. IEEE Trans Ind Electron 56:305–314

    Article  Google Scholar 

  16. Ui-Min C, June-Seok L, Kyo-Beum L (2014) New modulation strategy to balance the neutral-point voltage for three-level neutral-clamped inverter systems. IEEE Trans Energy Convers 29:91–100

    Article  Google Scholar 

  17. Pulikanti SR, Dahidah SA (2011) Voltage balancing control of three-level active NPC converter using SHE-PWM. IEEE Trans Power Deliv 26:258–267

    Article  Google Scholar 

  18. Ghennam T, Berkouk EM, Francois B (2010) A novel space–vector current control based on circular hysteresis areas of a three-phase neutral point-clamped inverter. IEEE Trans Ind Electron 57:2669–2678

    Article  Google Scholar 

  19. Lewicki A, Krzeminski Z, Abu-Rub H (2011) Space–vector pulse width modulation for three-level NPC converter with the neutral point voltage control. IEEE Trans Ind Electron 58:5076–5086

    Article  Google Scholar 

  20. Xiyou C, Kazerani M (2006) Space vector modulation control of an AC–DC–AC converter with a front-end diode rectifier and reduced dc-link capacitor. IEEE Trans Power Electron 21:1470–1478

    Article  Google Scholar 

  21. Huibin Z, Finney SJ, Massoud A, Williams BW (2008) An SVM algorithm to balance the capacitor voltages of the three-level NPC active power filter. IEEE Trans Power Electron 23:2694–2702

    Article  Google Scholar 

  22. Bouhali O, Francois B, Berkouk EM (2007) DC link capacitor voltage balancing in a three-phase diode clamped inverter controlled by a direct space vector of line-to-line voltages. IEEE Trans Power Electron 22:1636–1648

    Article  Google Scholar 

  23. Dongsheng Z, Didier GR (2001) Experimental comparisons of space vector neutral point balancing strategies for three-level topology. IEEE Trans Power Electron 16:872–879

    Article  Google Scholar 

  24. Nikola C, Dushan B (2000) A comprehensive study of neutral-point voltage balancing problem in three-level neutral-point-clamped voltage source PWM inverters. IEEE Trans Power Electron 15:242–249

    Google Scholar 

  25. Sergio B, Josep B, Dushan B, Sergio S (2004) The nearest three virtual space vector PWM–A modulation for the comprehensive neutral-point balancing in the three-level NPC inverter. IEEE Power Electron Lett 2:11–15

    Article  Google Scholar 

  26. Mishra MK, Joshi A, Ghosh A (2003) Control schemes for equalization of capacitor voltages in neutral clamped shunt compensator. IEEE Trans Power Deliv 18:538–544

    Article  Google Scholar 

  27. Yong L, Yanjian P, Fang L, Denis S, Daniil P, Chonggan L, Long L, Yijia C (2016) A controllably inductive filtering method with transformer-integrated linear reactor for power quality improvement of shipboard power system. In: IEEE transactions on power delivery

  28. Shengwei L, Yongli L, Jingliao S, Qiang J, Xuguang L (2009) A novel control algorithm for inverter-based distributed generation in unbalanced three phase power systems, In: International conference on sustainable power generation and supply, Nanjing, China, pp 1–6

Download references

Author information

Authors and Affiliations

  1. Engineering Department, Lancaster University, Lancaster, LA1 4YW, UK

    Peng Qian & Xiandong Ma

  2. College of Electrical and Information Engineering, Jiangsu University, Zhenjiang, China

    Guohai Liu & Zhaoling Chen

Authors
  1. Peng Qian
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Xiandong Ma
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Guohai Liu
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Zhaoling Chen
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Peng Qian.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Qian, P., Ma, X., Liu, G. et al. Reducing neutral-point voltage fluctuation in NPC three-level active power filters. Electr Eng 100, 721–732 (2018). https://doi.org/10.1007/s00202-017-0538-y

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00202-017-0538-y

Keywords

Search

Navigation