A comprehensive study of neutral-point voltage balancing problem inthree-level neutral-point-clamped voltage source PWM inverters

摘要

This paper explores the fundamental limitations of thenneutral-point voltage balancing problem for different loading conditionsnof three-level voltage source inverters. A new model in the DQncoordinate frame utilizing current switching functions is developed as anmeans to investigate theoretical limitations and to offer a morenintuitive insight into the problem. The low-frequency ripple of thenneutral point caused by certain loading conditions is reported andnquantified