Open Access

ARTICLE

A Low Common-Mode Voltage Virtual Space Vector Modulation of Three-Level Converters for Doubly-Fed Variable-Speed Pumped Storage Systems

Ziqiang Man¹, Lei Zhao², Zheng Tao¹, Shiming Cheng², Wei Yan¹, Gaoyue Zhong¹, Yu Lu¹, Wenming Zhang³, Li Zhang^3,*

1 NR Electric Co., Ltd., Nanjing, 211102, China
2 Construction and Management Branch of China Southern Power Grid Energy Storage Co., Ltd., Guangzhou, 510000, China
3 School of Electrical and Power Engineering, Hohai University, Nanjing, 211100, China

* Corresponding Author: Li Zhang. Email:

Energy Engineering 2025, 122(9), 3555-3572. https://doi.org/10.32604/ee.2025.067027

Received 23 April 2025; Accepted 18 June 2025; Issue published 26 August 2025

Abstract

With the rapid integration of renewable energy sources, modern power systems are increasingly challenged by heightened volatility and uncertainty. Doubly-fed variable-speed pumped storage units (DFVS-PSUs) have emerged as promising technologies for mitigating grid oscillations and enhancing system flexibility. However, the excitation converters in DFVS-PSUs are prone to significant issues such as elevated common-mode voltage (CMV) and neutral-point voltage (NPV) fluctuations, which can lead to electromagnetic interference and degrade transient performance. To address these challenges, an optimized virtual space vector pulse width modulation (OVSVPWM) strategy is proposed, aiming to suppress CMV and NPV simultaneously through coordinated multi-objective control. Specifically, a dynamic feedback mechanism is introduced to adjust the balancing factor of basic vectors in the synthesized virtual small vector in real-time, achieving autonomous balancing of the NPV. To address the excessive switching actions introduced by the OVSVPWM strategy, a phase duty ratio-based sequence reconstruction method is adopted, which reduces the total number of switching actions to half of the original. A zero-level buffering scheme is employed to reconstruct the single-phase voltage-level output sequence, achieving peak CMV suppression down to u_dc/6. Simulation results demonstrate that the proposed strategy significantly improves electromagnetic compatibility and operational stability while maintaining high power quality.

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Keywords

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