Proceedings of the KIPE Conference (전력전자학회:학술대회논문집)
- 2015.07a
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- Pages.177-178
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- 2015
Neutral Point Balancing Algorithm for Multi-level Converter under Unbalanced Operating Conditions
- Jung, Kyungsub (Dept. of Elec. Eng., Smart Grid Research Center, Chonbuk Nat'l. Univ.) ;
- Suh, Yongsug (Dept. of Elec. Eng., Smart Grid Research Center, Chonbuk Nat'l. Univ.)
- Published : 2015.07.07
Abstract
This paper presents a neutral point deviation compensating control algorithm applied to a 3-level NPC converter. The neutral point deviation is analyzed with a focus on the current flowing out of or into the neutral point of the dc link. Based on the zero sequence components of the reference voltages, this paper analyzes the neutral point deviation and balancing control for 3-level NPC converter. An analytical method is proposed to calculate the injected zero sequence voltage for NP balancing based on average neutral current. This paper also proposes a control scheme compensating for the neutral point deviation under generalized unbalanced grid operating conditions. The positive and negative sequence components of the pole voltages and ac input currents are employed to accurately explain the behavior of 3-level NPC converter. Simulation and experimental results for a test set up of 30kW are shown to verify the validity of the proposed algorithm.
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