Questions regarding Power Factor Correction circuits

Thread Starter

SiCEngineer

Joined May 22, 2019
238
I am looking into designing a power factor correction circuit as a pre-converter for my DC-DC converter, which I have designed to improve the efficiency and provide a regulated DC voltage to the main DC-DC converter.

The PFC converters I have witnessed online are AC-DC converters, using the AC input to power factor correct and provide stable DC output at high power factor. However, my converter has 243VDC input voltage. How could I use a PFC converter with this input voltage? Basically, is there a way to do PFC in a DC-DC rather than an AC-DC way?

To me it doesn't make sense as I don't really have any information regarding the AC quantities because I have a varying DC input that is rectified from aircraft AC. But I am unsure if there is a way to measure and correct power factor in this situation?
 

Marc Sugrue

Joined Jan 19, 2018
153
Power factor is only applicable to AC power conversion, the intent is to match the voltage and phase relationship, and in some cases meet harmonic performance. Efficiency is completely different and improvements are only made through choice of topology, improved magentics (minimising leakage currents in transformers), synchronous rectifiers, Controlling switching speeds (Fast switching minimises switching losses), LOW RDSon of FET, Minimise losses in general (no snubbers etc) etc...

Everything is compromise though, High Frequencies can have EMI concerns etc, Low frequencies typically have larger currents

If efficiency is the target then you should start with a set of requirments of what the target system is. Typically 80-90% efficiency can be achievable for DC/DC but typically costs are the typically restriction.
 
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