Power-Factor Improvement of Single-Phase Converter by Means of Bias Voltage Control

Power-factor improvement and harmonic reduction in ac line current, as well as stable and reliable operation, are very significant areas in the high-power ac-dc converter. The improvements of these characteristics of the single-phase converter may be generally difficult compared with the polyphase type. A new converter scheme suitable for the high power single-phase converter to overcome the above problems is presented. The basic configuration and principle of operation of the new converter scheme, theoretical characteristics and design indexes, and the drive system and characteristics of a dc series motor by this scheme are described. The basic principle of operation is verified and the feasibility of this converter system is demonstrated by experiments.