A comparative study of circulating current free and circulating current cycloconverters

A cycloconverter is a power electronic device used to produce adjustable voltage adjustable frequency AC power from a constant voltage constant frequency AC source without any DC link. Cycloconverters produce significant harmonics, sub-harmonics and non-standard frequency components in their output voltages. However harmonic behavior of cycloconverters widely depends of their pulse number, structure and switching strategy. In this paper the impact of different cycloconverter structures on its harmonic behavior is studied. Two major cycloconverter structures, i.e. non-circulating current cycloconverter (NCC) and circulating current cycloconverter (CC), are compared completely in output voltage and current characteristics. Simulation results using MATLAB software are used to evaluate the analysis and signal THDs and harmonic components are calculated for further comparison.