Influence of switching sequences on the neutral point voltage balance in a three-level voltage source invertor

Abstract

BACKGROUND: Ensuring the voltage balance of the neutral point of the DC link within acceptable limits is one of the mandatory requirements during the operation of a three-level autonomous neutral point clamped voltage source inverter. It is known that neutral point voltage imbalance can adversely affect the operation of the inverter and the load at all, lead to the failure of both power switches and capacitors in the DC link. Neutral point voltage imbalance mostly often occurs due to the asymmetry of the nominal values of DC capacitors, inconsistent properties of switching devices, asymmetric three-phase load, and also due to the imperfection of the converter control algorithm.

AIMS: Selection of the optimal switching sequence that ensures the smallest deviation of the neutral point voltage and the number of switching of power switches in a three-level voltage source inverter.

METHODS: For an objective comparison of the considered switching sequences and their influence on the neutral point voltage balance, a simulation model of a three-level neutral point clamped voltage source inverter was developed in the MATLAB/Simulink software. To control this inverter, a space vector modulation method was used with three different switching sequences: five-segment, seven-segment and standard.

RESULTS: The topology of a three-level neutral point clamped voltage source inverter is presented. The experimental dependencies of the neutral point voltage deviation error was taken with a change in the modulation coefficient, the frequency of the fundamental harmonic at the inverter output, and load characteristics for three different switching sequences.

CONCLUSIONS: In this paper, the influence of the basic vectors and the influence of switching sequences on the neutral point voltage balance are studied. Combinations of states of large and zero basic vectors do not affect the neutral point voltage. For the medium basic vectors, the neutral point voltage can increase or decrease depending on the operating conditions of the inverter. The small basic vectors significantly affect the neutral point voltage. Considering the abovementioned, the seven-segment sequence that ensures both the optimal balance of the neutral point voltage and the level of switching losses should be considered as the best switching sequence for a three-level inverter.

Keywords

multilevel inverter / three-level neutral point clamped voltage source inverter / neutral point voltage / pulse-width modulation / space vector modulation

References

[1] Gorozhankin AN, Dudkin MM. Algorithms and Control Systems for Electric Drives of Cold Pipe-Rolling Mills. Russian Electrical Engineering. 2020;91(7):440–446. doi: 10.3103/s1068371220070068

[2] Gorozhankin A.N., Dudkin M.M. Algorithms and Control Systems for Electric Drives of Cold Pipe-Rolling Mills // Russian Electrical Engineering. 2020. Vol. 91, № 7. P. 440–446. doi: 10.3103/s1068371220070068

[3] Dudkin MM. Energy-saving technologies in test benches using single-phase reversible converters. Vestnik YuUrGU. Seriya «Energetika». 2013;13(1):5–18. (in Russ.)

[4] Дудкин М.М. Энергосберегающие технологии в испытательных стендах с использованием однофазных обратимых преобразователей // Вестник ЮУрГУ. Серия «Энергетика». 2013. Т. 13, № 1. С. 5–18.

[5] Khramshim RR, Khramshin TR, Khramshina EA, et al. Multilevel high-voltage frequency converter for electric drive. Izvestiya Tulskogo gosudarstvennogo universiteta. Tekhnicheskie nauki. 2010:191-196. (in Russ.)

[6] Храмшим Р.Р., Храмшин Т.Р., Храмшина Е.А., и др. Многоуровневый высоковольтный преобразователь частоты для электропривода // Известия Тульского государственного университета. Технические науки. 2010. C. 191-196.

[7] Donskoy N, Ivanov A, Matison V, et al. Multilevel autonomous inverters for electric drive and electric power industry. Silovaya Elektronika. 2008;1:43-46. (in Russ.)

[8] Донской Н., Иванов А., Матисон В., и др. Многоуровневые автономные инверторы для электропривода и электроэнергетики // Силовая Электроника. 2008. № 1. C. 43-46.

[9] Makarov VG, Khaybrakhmanov RN. Multilevel voltage inverters. Topology overview and application. Vestnik tekhnologicheskogo universiteta. 2016;19(22):134-138. (in Russ.)

[10] Макаров В.Г., Хайбрахманов Р.Н. Многоуровневые инверторы напряжения. Обзор топологий и применение // Вестник технологического университета. 2016. Т.19. № 22. C. 134-138.

[11] Lazarev SA. Application of voltage inverters in high-voltage electric drive. Ekspozitsiya Neft Gaz. 2013:31-35. (in Russ.)

[12] Лазарев С.А. Применение инверторов напряжения в высоковольтном электроприводе // Экспозиция Нефть Газ. 2013. С. 31-35.

[13] Peddapelli SK. Pulse Width Modulation: Analysis and Performance in multilevel inverter. Oldenbourg: De Gruyter Oldenbourg; 2017.

[14] Peddapelli S.K. Pulse Width Modulation: Analysis and Performance in multilevel inverter. Oldenbourg: De Gruyter Oldenbourg, 2017.

[15] Holmes GD, Lipo TA. Pulse Width Modulation for Power Converters: Principles and Practice. New York: Wiley-IEEE Press; 2003.

[16] Holmes G.D., Lipo T.A. Pulse Width Modulation for Power Converters: Principles and Practice. New York: Wiley-IEEE Press, 2003.

[17] Choi U-M, Lee K-B. Neutral-Point Voltage Balancing Method for Three-Level Inverter Systems with a Time-Offset Estimation Scheme. Journal of Power Electronics. 2013;13(2):243–249. doi: 10.6113/JPE.2013.13.2.243

[18] Choi U.-M., Lee K.-B. Neutral-Point Voltage Balancing Method for Three-Level Inverter Systems with a Time-Offset Estimation Scheme // Journal of Power Electronics. 2013. Vol. 13. № 2. P. 243–249. doi: 10.6113/JPE.2013.13.2.243

[19] Abulveleev IR, Khramshin TR, Kornilov GP, et al. Principles of constructing vector pulse-width modulation for a three-level inverter. Elektrotekhnicheskie sistemy i kompleksy. 2016;4(33):72-77. (in Russ.)

[20] Абулвелеев И.Р., Храмшин Т.Р., Корнилов Г.П., и др. Принципы построения векторной широтно-импульсной модуляции для трехуровневого инвертора // Электротехнические системы и комплексы. 2016. № 4 (33). C. 72-77.

[21] Busquets-Monge S, Bordonau J, Boroyevich D, et al. The nearest three virtual space vector PWM - a modulation for the comprehensive neutral-point balancing in the three-level NPC inverter. IEEE Power Electronics Letters. 2004. Vol. 2, N 1. doi: 10.1109/LPEL.2004.828445

[22] Busquets-Monge S., Bordonau J., Boroyevich D., et al. The nearest three virtual space vector PWM - a modulation for the comprehensive neutral-point balancing in the three-level NPC inverter // IEEE Power Electronics Letters. 2004. Vol. 2, N 1. doi: 10.1109/LPEL.2004.828445

[23] Gelman MV, Dudkin MM. Valve converters of direct and alternating current. Chelyabinsk: Izd. tsentr Yuzhno-Uralskogo gosudarstvennogo universiteta; 2013. (in Russ.)

[24] Гельман М.В., Дудкин М.М. Вентильные преобразователи постоянного и переменного тока. Челябинск: Изд. центр Южно-Уральского государственного университета, 2013.

[25] Lewicki A, Krzeminski Z, Abu-Rub H. Space-Vector Pulse width Modulation for Three-Level NPC Converter With the Neutral Point Voltage Control. IEEE Transactions on Industrial Electronics. 2011;58(11):5076-5086. doi: 10.1109/TIE.2011.2119453

[26] Lewicki A., Krzeminski Z., Abu-Rub H. Space-Vector Pulse width Modulation for Three-Level NPC Converter With the Neutral Point Voltage Control // IEEE Transactions on Industrial Electronics. 2011. Vol. 58, N 11. P. 5076-5086. doi: 10.1109/TIE.2011.2119453

[27] Koyama M, Fujii T, Uchida R, et al. Space voltage vector-based new PWM method for large capacity three-level GTO inverter. In: Proceedings of the 1992 International Conference on Industrial Electronics, Control, Instrumentation, and Automation. San Diego: IEEE; 1992:271-276. doi: 10.1109/IECON.1992.254621.

[28] Koyama M., Fujii T., Uchida R., et al. Space voltage vector-based new PWM method for large capacity three-level GTO inverter // Proceedings of the 1992 International Conference on Industrial Electronics, Control, Instrumentation, and Automation. San Diego: IEEE, 1992. P. 271-276. doi: 10.1109/IECON.1992.254621.

RIGHTS & PERMISSIONS

Eco-Vector