I wonder if we should be calling LED drivers, SMPS etc power converters
http://www.electropedia.org/iev/iev.nsf/index?openform&part=551
One might, but it would be more reasonable if the IEC had heard (at some point during the last 6 or so decades!) about the development of semiconductors! ....
IEC said:
(electronic) (power) converter
an operative unit for electronic power conversion, comprising one or more electronic valve devices, transformers and filters if necessary and auxiliaries if any
One also wonders how appropriate it is to talk about
power converters, when what is being converted is voltage. I realise that 'power' is used in different senses but, at the least, there is some ambiguity there - which should not really exist in an official definition.
AFAIK all power converters that do not utilise a linear type transformer, "change the frequency". They take an input voltage, rectify it if AC, chop it at a certain frequency, usually in the kHz range, pass it through a small transformer and regulate it (rectifying if dc is required). Chopping at several kilohertz allows very small and very efficient transformers to be used.
Yes, I'm sure that is all true - and if the output is 'high' frequency AC, then the device would clearly not satisfy the IEC definition of a 'transformer'. However, the (seemingly poor) IEC definition doesn't even say that either input or output have to be AC - so an electronic DC/DC converter would technically qualify as a 'transformer'! If the load cannot cope with 'high frequency' AC, I suppose one would have to first create DC at the desired voltage (as above, and then use an inverter (or chopper!) to create AC of the required frequency - and if that frequency were the same as the input frequency (it could even be frequency- and phase-locked to the supply!), we would be back to the situation in which, if one regarded the device as a 'black box', it might be said to satisfy the IEC definition of 'transformer (despite 'internal' frequency conversion).
The chopper stage is where I believe the IEC is referring to frequency change
Maybe - as I've said, who knows! However, as I've just said, I'm more inclined to guess that they would regard the device as a 'black box', in which case, as above, an electronic device might, in some situations, qualify as a 'transformer'.
All of this really illustrates what we both seem to believe, namely that the IEC definition of 'transformer' appears, to put it kindly, to be 'far from ideal'!
Kind Regards, John