In variable speed constant frequency(VSCF) machines, I would like to have expert comment on reliability aspect of cycloconverter vs. mechanical CSD.
Config.1 : VSVF machine + Cycloconverter = VSCF
Config.2 : mech. CSD + Synch Machine = VSCF

The cycloconverter has been a muture technology and widely used in high power applications, such as mining industry. The technology can be tracked back 30 years ago. I am not worried about its reliability since it has been proved for such a long period of time.

If I understand correctly about your questions, config 2 is a mechanical device based solution. Two key points for variable speed drive based configuration are efficiency and reliability. As such, if you consider about reliability, go for config 1. No doubt.

Thanks Wang,yes config.2 is mechanical based and proved highly reliable in aerospace and still used a lot for VSCF.Yes maintenance aspect are there with config.2 but My doubt comes with electronics in aerospace for cycloconverter configuration and no. of parallel devices needed to achieve same reliability level. This is based on inputs about More/All Electric aircraft programme where no. of parallel electric devices are needed to achieve same reliability level. May be someone has already done this analysis and I need not to redo. Another thing is magnetic interference due to switching device in case of Cycloconverter.

also please consider that the output frequency can only be about 20% to 30% of its input frequency. They are used mainly for low speed applications.

sorry. I'm talking about cycloconverters being used for low speed applications.

@George :what may be technological differences for low speed and high speed applications from cycloconverter point of view and why this 20% to 30% variation cap on output frequency not applicable for high speed applications.