A SINGLE PHASE TO THREE PHASE DRIVE SYSTEM USING TWO DC LINK PARALLEL SINGLE-PHASE RECTIFIERS

Abstract

Single-phase ac to three-phase ac converters are needed in numerous applications,
including motor drives used for residential applications. These converters, however, suffer
from an inherent problem of mismatch between instantaneous input and output powers.
Specifically, the instantaneous input power has a dc component along with an alternating
component with double-line frequency; while the three-phase instantaneous output power is
only dc.Conventional single-phase ac to three phase ac converters use large electrolytic
capacitors to handle this mismatch of power. However, these electrolytic capacitors may have
high failure rates, which contributes to reduced lifetime of the converters. Moreover, these
capacitors can be bulky and heavy. This paper introduces a new single-phase ac to three-phase
ac converter that uses a small film capacitor instead of large electrolytic capacitors. Despite
using a small film capacitor, the double-line frequency harmonic does not appear at the input
or output currents/voltages.