Three-phase voltage-fed high-power-factor converter using simplified predictive instantaneous-current control and phase-decoupling theory

Abstract

Since a three-phase circuit has phase interference, control/modulation in three-phase converters becomes very complicated as compared with single-phase converters. The phase interference problem has not been discussed in depth in any published work. As the primary objective, this paper describes an analysis of phase interference in a three-phase voltage-fed converter circuit and the resultant phase-decoupled equivalent circuits expressed with local-averaging value (or averaging value in a control/modulation period). A simplification of a predictive instantaneous-current control for a voltage-fed high-power-factor converter is then introduced as the secondary objective. By combining the proposed techniques, a simple control/modulation scheme for three-phase high-power-factor converters is obtained. A controller/modulator for experimental setup is introduced to demonstrate the simplicity achieved by the proposed theories. The pulse area modulation scheme, employed in the modulator to compensate modulation errors caused by ripples of the output voltage, is also introduced. To show the validity and applicability of the proposed theory, experimental results obtained from a 2-kW setup are shown. Finally, the author draws conclusions from the work. © 1997 Scripta Technica, Inc. Electr Eng Jpn, 118 (4): 70–83, 1997