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This paper proposes a technique for improving the input-output current quality in inverter system using small capacitor. The small dc-

link capacitor in three-level inverter has advantages such as cost, volume, life-time, and reliability compared to the large dc-link

capacitor. The small capacitors, however, cannot compensate for the difference in input-output power, resulting in deterioration input

current quality. In addition, the ripple of the neutral-point voltage generated using three-level NPC inverter degrade the output current

quality. Therefore, in order to solve these problems the proposed method is implemented by applying two techniques. First, the

additional circuit is applied to improve the input current. Second, the neutral voltage ripple reduction technique is applied to improve

the output current. The effectiveness of the proposed techniques are verified by simulation and experimental results.