A new topology for the three-phase to three-phase cycloconverters

This paper proposes a new topology for three-phase to three-phase cycloconverters. In the proposed topology, in order to generate the desired output voltage, the main states of switches are decreased in comparison with conventional topologies of three-phase to three-phase cycloconverters which can improve the performance of the cycloconverter. Increasing of the maximum output/input voltage transfer ratio of converter up to 1.5 is one of the main advantages of the proposed cycloconverter. In addition, there is no restriction for generation of output frequency consequently; the proposed cycloconverter can be applied as both step-up and step down converters. The control strategy of cycloconverter is based on pulse width modulation (PWM) method. Using PWM based control strategy, the injected harmonics will be produced around the switching frequency and its multiple coefficients and the size of filters will be decreased. Also, a feedback of output voltage is used in the control strategy of the proposed converter to improve its performance. The proposed cycloconverter is simulated using PSCAD/EMTDC software and simulation results for both balanced and unbalanced load are presented to validate the effectiveness and performances of the new proposed topology.