DC-link capacitor voltage balance strategy of independent double three-phase common bus five-level NPC/H-bridge inverter based on finite control set

• Published in: IET power electronics Vol. 13; no. 8; pp. 1546 - 1553
• Main Authors: Wei, Wang, Guangsen, Wang
• Format: Journal Article
• Language: English
• Published: The Institution of Engineering and Technology 17.06.2020
• Subjects: capacitors; DC‐link capacitance voltage difference; DC‐link capacitor voltage balance strategy; DC‐link capacitor voltage fluctuation; DC‐link capacitor voltage imbalance problem; electromagnetic launch system; high‐current conditions; instant high‐power; invertors; optimised strategy; optimised voltage balance strategy; power capacitors; Research Article; three‐phase switch vector combinations; variation trend; voltage balance finite control set; voltage control; voltage difference fluctuation; DC-link capacitance voltage difference; DC-link capacitor voltage fluctuation; DC-link capacitor voltage imbalance problem; high-current conditions; invertors; capacitors; three-phase switch vector combinations; variation trend; optimised strategy; DC-link capacitor voltage balance strategy; voltage difference fluctuation; voltage balance finite control set; electromagnetic launch system; instant high-power; optimised voltage balance strategy; power capacitors; voltage control
• ISSN: 1755-4535; 1755-4543; 1755-4543
• DOI: 10.1049/iet-pel.2019.1131

This study aims at the DC-link capacitor voltage imbalance problem of independent double three-phase common bus five-level neutral point-clamped/H-bridge inverter, which is applied to an electromagnetic launch system under instant high-power and high-current conditions. First, the traditional method of voltage balance strategy based on redundant vectors is described, and the key factors leading to the DC-link capacitor voltage fluctuation is analysed in detail. Second, the objective function is constructed to predict the variation trend of DC-link capacitance voltage difference. Third, an optimised voltage balance strategy is proposed. At first, the optimised strategy calculates the variation trends of the voltage difference for all three-phase switch vector combinations. Then, the results make up a voltage balance finite control set. At last, compare the results in the set to select the vector combination corresponding to the minimum variation for output. Finally, tested by the semi-physical real-time simulation platform, and the proposed optimised voltage balance strategy is verified effective for improving DC-link capacitor voltage imbalance and inhibiting the voltage difference fluctuation.