Single-Phase to Three-Phase Cycloconverter

[nicy12]

When my classmate report about cycloconverters. He discussed about different classifications and types of cycloconverters. He also discussed how Single-phase to Single-Phase Cycloconverters operate. But when he approached Three-Phase to Single-Phase and Three-Phase to Three-Phase Cycloconverter's operations, he discussed it not very well leading to a lot of confusions. Almost all of the answers to those confusions was answered through Internet except one:

>> Is there any Single-Phase to Three-Phase Cycloconverter existing? How does it operate (I mean how does the Single-Phase frequency input converted into Three-Phase frequency output)? What applications does it suits best?

 

[zoki85]

>> Is there any Single-Phase to Three-Phase Cycloconverter existing? How does it operate (I mean how does the Single-Phase frequency input converted into Three-Phase frequency output)? What applications does it suits best?

I'm sure that about theory and toplogies of 3-phase to 3-phase cycloconverters you can find a lot in power electronics textbooks, online sources etc.They are more common in practice than 1-phase to 3-phase cycloconverters. In order to make a 1-phase to 3-phase cycloconvertor, first step is to turn 1-phase input to 3 phase input. That can be achived by phase convertors. There are two types:

1.Static phase converter comprising autotransformer and capacitors bank can generate a symmetrical 3-phase supply from a single phase supply. This method has disadvantages like limitations of cap bank size with regard to higher powers and it's dependence on the load impedance for satisfactory operation.

2.Rotary phase converter which is a rotating transformer with stator having 3 primary windings and rotor having 1 secondary winding. A single phase voltage is applied to one of the primary windings and, when machine runs, 3-phase symmetrical system of voltages is induced since stationary windings are evenly spaced around the stator. Then this voltage is taken out of the converter as the manufactured third leg. This method is superior and can be still found used in industry.

After the phase conversion is done, one of 3-phase to 3-phase cycloconvertor topologies with semiconductor switches can be used. It must said that sometimes AC→DC→AC toplogies (single phase AC frequency 1 -rectifier- PWM 3 phase wave synthetization frequency 2) is referred to as cycloconvertor. This is not a true cycloconvertor. True cyclonvertor converts AC power of one frequency into AC power of other frequency without any DC stage in between.