Novel five-level inverter PWM control in 3-phase 4-wire system for power quality

During the past decades, three-phase three-wire systems have played a very important role in power electronics research, especially in PWM studies. However, on the distribution side, there are many three-phase four-wire equipments installed. In most recent researches, four-arm inverters are proposed to solve three-phase four-wire system issues. In the PWM researches, almost all the studies are focused on two-dimensional PWM techniques in the α-β frame. However, three-leg inverters can be applied to compensate the power quality issues including the zero-sequence compensation by the novel PWM technique-three dimensional PWM. In this paper, a novel 3D PWM control strategy is applied to reduce the control complexity of the 5-level inverter system. With this novel control method, the three-arm five-level inverter can be used in three-phase four-wired system, instead of the four-arm five-level inverter, to compensate the power quality issues as well as the neutral line current.