Basic Characteristics of Cycloconverter for Linking Commercial and High-Frequency Distribution Lines

A new method to improve the power factor and current waveform on the commercial ac system is proposed. The frequency of a local distribution line in a factory or a chemical plant is made high, up to about 500 Hz. The local distribution line is linked directly to the commercial line by using a cycloconverter operating in circulating current mode. Quasi-sinusoidal current with unity displacement factor is realized on the commercial line side regardless of the consumed power by loads. The system configuration and the basic principle of operation of the cycloconverter for linking both lines are described. The influence of system parameters on the operation limit is investigated based on the power equilibrium constraints. Experimental results obtained in the 5.2KVA laboratory system show the validity of the proposed system.