Hyun-Hee Lee, "전동기 구동용 3-레벨 인버터의 신뢰성을 위한 중성점 전압 제어,” 아주대학교 공학석사 학위 논문, 2012. > Paper

This paper proposes a method for neutral-point voltage balancing control for a three-level inverter that uses discontinuous pulse

width modulation (DPWM). The reliability of a three-level inverter system is influenced by the neutral-point voltage balance. Generally,

the offset voltage is added to reference voltages in the conventional voltage balancing control method. However, when using DPWM,

only limited balance of the neutral-point voltage is possible because turn-on and turn-off switching occur at regular intervals. The

proposed method is implemented by adjusting the discontinuous pulse width of positive and negative cycle. The method maintains

low switching loss and effective voltage balance, without the need for complex calculations. Simulation and experimental results

confirm the feasibility and effectiveness of the proposed method.