Study on neutral-point voltage balancing control in three-level grid-connected photovoltaic inverter

Jiajun Lin

doi:10.54254/2977-3903/2025.21441

Research Article

Open access

Published on 11 March 2025

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Lin,J. (2025). Study on neutral-point voltage balancing control in three-level grid-connected photovoltaic inverter. Advances in Engineering Innovation,16(1),36-41.

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Study on neutral-point voltage balancing control in three-level grid-connected photovoltaic inverter

Jiajun Lin *^,1,

¹ Guangzhou Vocational University of Science and Technology

* Author to whom correspondence should be addressed.

https://doi.org/10.54254/2977-3903/2025.21441

Abstract

Three-level photovoltaic grid-connected inverters are widely used in the photovoltaic grid-connected systems because of their high efficiency and low harmonic characteristics. However, the major problem of the three-level inverter has always been its core challenge, significantly affecting its system reliability and performance. This study reviews the causes of neutral-point voltage imbalance, discusses three typical three-level inverter topologies, including neutral-point-clamped inverter, flying capacitor inverter, and cascaded H-bridge inverter, and compares their application effectiveness in neutral-point voltage balancing control. Then, it analyzes several common control methods, such as the modulation method based on space vector, model predictive control, and relatively new techniques for controlling virtual neutral-point voltage. The comparative analysis results show that space vector is easy to implement, but the neutral-point voltage fluctuates markedly; model predictive control exhibits strong dynamic response performance but has a high computational complexity; virtual neutral-point voltage does not rely on the real-time feedback of actual neutral-point voltage. In conclusion, this study makes a prospect for the development trends of neutral-point voltage balance control technologies and proposes possible development directions for further improving the performance of grid-connected photovoltaic inverters.

Keywords

three-level grid-connected photovoltaic inverter, neutral-point voltage balancing, control method.

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References

[1]. Guo, J. (2018). Research on control strategy of three-level photovoltaic inverter (Unpublished doctoral dissertation). Wuhan University of Technology.

[2]. Wang, C., & Liu, Y. (2024). Research on SVPWM modulation strategy based on three-level typical topology structure. Wireless Internet Technology Magazine Agency, 21(12), 1-6+10.

[3]. Wang, M., Wang, L., & Sun, Y. (2015). A neutral-point voltage balancing control method based on model predictive control for T-type three-level inverter. Journal of Electrical Engineering, 10(09), 66-72.

[4]. Cheng, D., Wang, X., Zhu, T., et al. (2018). A neutral-point potential balance control strategy for three-level inverter based on VSVPWM. Journal of Measurement Science and Instrumentation, 9(04), 397-404.

[5]. Yao, C. (2024). Analysis of solar photovoltaic power generation technology and its application. Electrical Equipment and Economy, (10), 82-85.

[6]. Jiang, L. (2009). Awareness of the point potential balance problem in three-level inverters. China Science and Technology Information, (18), 141.

[7]. Zhuang, Y. (2020). Research on control strategy of three-level converter under grid unbalance condition (Unpublished doctoral dissertation). Harbin Institute of Technology.

[8]. Wang, Y., Gao, L., Ma, L., et al. (2024). Research on high-frequency isolated NPC three-level inverter for frequency conversion and speed regulation. Applied Sciences, 14(21), 9673.

[9]. Li, Y. (2015). Research on neutral-point potential balance control of three-level NPC inverter. Mechatronics, 21(01), 45-48.

[10]. Rohner, G., Huber, J., Mirić, S., et al. (2024). Comparative evaluation of three-phase three-level flying capacitor and stacked polyphase bridge GaN inverter systems for integrated motor drives. Electronics, 13(7).

[11]. Wang, C., He, Y., Liu, Y., et al. (2016). Research of the unity theory between the space vector and the carrier-based pulse width modulation strategies in flying capacitor multilevel inverters. Proceedings of the CSEE, 36(15), 4172-4184.

[12]. Ye, M., & Kang, L. (2020). Research on power balance control strategy for single-phase cascaded H-bridge photovoltaic grid-connected inverter. Journal of Power Supply, 18(04), 137-143.

[13]. Zhang, Y., Li, C., Zhu, C., et al. (2011). Three-level H-bridge cascade type multi-level inverter. Transactions of China Electrotechnical Society, 26(05), 78-82.

[14]. Ye, Y. (2020). The improvement for the SVPWM algorithm and neutral-point potential balance control method of three-level inverter. Journal of Shandong Agricultural University (Natural Science Edition), 51(06), 1126-1131.

[15]. Engineering. (2020). New findings from Jiangsu Normal University in engineering provide new insights (Multi-objective optimal model predictive control for three-level ANPC grid-connected inverter). Journal of Engineering, 1770.

[16]. Liu, J., Yuan, Q., Dai, P., et al. (2013). Neutral-point voltage balance control based on the virtual space vector. Power Electronics, 47(05), 15-17.

[17]. Hu, L., Guo, C., Han, J., et al. (2024). SVPWM-based narrow pulse suppression strategy for three-level inverter. High Voltage Engineering, 1-10.

[18]. Liu, J., Huang, J., Yang, Q., et al. (2020). Predictive control of NPC-type three-level grid-connected inverters with virtual space vector modulation. Journal of Henan Normal University (Natural Science Edition).

Cite this article

Lin,J. (2025). Study on neutral-point voltage balancing control in three-level grid-connected photovoltaic inverter. Advances in Engineering Innovation,16(1),36-41.

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About volume

Journal：Advances in Engineering Innovation

Volume number: Vol.16

ISSN：2977-3903(Print) / 2977-3911(Online)

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