The control method of 3-phase PWM converter for 3-phase 3-wired imbalanced AC voltages

Abstract

In general, unbalanced 3-phase input voltage source in AC power system are inevitable since problems such as not only thunderbolt but also turning the switch on and off of the single phase load. In order to avoid such problems, conventional converters are provided with an uninterruptible power supply (UPS) or other additional storage devices such as capacitors and/or batteries. This paper describes that the 3-phase PWM converter with the compensated control can keep the rated output power stable by getting enough energy from the existing source of the phase voltages even if the unbalanced voltage happens to the 3-phase 3-wire AC system. There are some papers described about the control method of the PWM converter for 3-phase 4-wire system with unbalanced input voltages. However, there has been never the paper described for 3-phase 3-wire system. This paper is the new proposal to clear the problem on the PWM converter for 3-phase 3-wire AC system with unbalanced input voltages.