1.3 Three-Phase to Three-Phase (3f-3f) Cycloconverter:
If the outputs of 3 3f-1f converters of the same kind are connected in wye or delta and if the output voltages are 2p/3 radians phase shifted from each other, the resulting converter is a threephase to three-phase (3f-3f) cycloconverter. The resulting cycloconverters are shown in Figs. 7 and 8 with wye connections. If the three converters connected are half-wave converters, then the new converter is called a 3f-3f half-wave cycloconverter. If instead, bridge converters are used, then the result is a 3f-3f bridge cycloconverter. 3f-3f half-wave cycloconverter is also called a 3-pulse cycloconverter or an 18-thyristor cycloconverter. On the other hand, the 3f-3f bridge cycloconverter is also called a 6-pulse cycloconverter or a 36-thyristor cycloconverter. The operation of each phase is explained in the previous section.