Hyo-Chul In, Seok-Min Kim, and Kyo-Beum Lee, "Design and Control of Small DC-link Capacitor-Based Three-Level Inverter with Neutral-Point Voltage Balancing," Energies, vol. 11, no. 6, pp. 1–18, Jun. 2018. -SCIE > Paper

This paper presents a method to improve the quality of input-output currents in a three-level neutral-point clamped (NPC) inverter

with small direct current-link (DC-link) capacitor systems. The inverter systems with the small DC-link capacitors have several

advantages in terms of cost, volume, life-time, and reliability when compared to inverters that use large DC-link capacitors. However,

there are problems with respect to the deterioration of the input current quality and a severe ripple of neutral-point voltage (NPV),

which can cause an aggravated output current. To mitigate these issues, an additional circuit is applied for the input current shaping

and a compensation algorithm is applied to reduce the ripple voltage of NPV. The effectiveness of the proposed design and control

method is verified with various simulation and experimental results.