Journal of Electrical Engineering & Technology

, Volume 14, Issue 6, pp 2389–2398 | Cite as

A Simplified Common-Mode Voltage Suppression and Neutral-Point Potential Control for the NPC Three-Level Inverter

  • Qingqing YuanEmail author
  • Jinyue Qian
  • An Li
Original Article


Neutral-point potential unbalancing is an inherent disadvantage of NPC three-level inverter. Traditional control methods, e.g. the space vector PWM (SVPWM) considering balance factor or the model predictive control (MPC), usually needs large amounts of calculation and the common-mode voltage usually keeps large due to the zero vectors being involved in the modulation or the roll optimization. Aiming at above problems, this paper proposes a simplified model predictive algorithm based on the characteristics analysis on the unbalancing and common-mode voltage. Firstly, an approximate two-level structure containing 12 vectors is proposed by the reduced-order processing for the three-level structure, which solves the calculation complexity problem. Meanwhile, multi-constraints including switching frequency, neutral-point potential deviation and the common-mode voltage, are constructed within the roll optimization items of the MPC scheme to make common-mode voltage being restricted less than 1/6 DC voltage while the switching frequency is almost constant. Finally, experiments were carried out to verify that this method can realize a neutral-point voltage balance and a low common-mode voltage along with less execution time.


NPC three-level inverter Neutral-point potential Common-mode voltage Reduced-order processing 



Funding was provided by Shanghai Sailing Program (CN) (Grant no. 18YF1418300) and Key Laboratory of Control Power Transmission and Conversion (SJTU CN) (Grant no. 2016AC04).


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Copyright information

© The Korean Institute of Electrical Engineers 2019

Authors and Affiliations

  1. 1.Electrical DepartmentUniversity of Shanghai for Science and TechnologyShanghaiChina
  2. 2.Key Laboratory of Control of Power Transmission and Conversion (SJTU)Ministry of EducationShanghaiChina

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