Bidirectional DCDC Converter

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No. Please explain more details of this problem.

Thanks in advance.

You are missing a lot. Start with power going into port A on a presumed device; this gives power out of port B. But there is a filter capacitor on port B, so port B sees a power source - and acts like an input and converts that to power at port A. But port a must have a filter capacitor when it is acting like an output, so.... See the contradiction?

Do a web search for "synchronous rectification" -- it's pretty much what you describe.

Yes, you can build bi-directional synchronous converters. But for your application, I think you may find that your motor used as a generator produces significantly less voltage than it requires as a motor, so you may be better off with two separate circuits each optimized for its own job, and logic to control them.

That is already used in some electric/hybrid vehicles. Search for "regenerative braking bidirectional converter". You'll find tons of information.

Can't find the sense in what you wrote, and especially in your attempt to relate capacitors with power sources, or with outputs. The Buck converter, for instance, does not need a capacitor at its output.

Hello Mochuelo,

Like this one:

Regards, Joerg

...and it *cannot* work in reverse!

...which is not whathe was relating to at all.

Yep, it can and does work just fine.

I have a few small planar forward SMPS sitting in front of me that use synchronous rectification (FETs instead of diodes). At no load, because the FET happily conducts current in either direction when ON, the output inductor current is a triangle wave centred on zero amps - no discontinuous inductor current :). When the primary FETs turn ON, the initial primary current is negative. Voila, reverse power flow.

Cheers Terry

Yes it is. Who cares where the reverse power comes from (in this case the output inductor) its still flowing backwards.

(+ve Dc bus volts)*(-ve primary current) = -ve power.

Cheers Terry

Yes it can. Use a synchronous rectifier. Then turn off the main FET (which has an anti-parallel diode) and what do you have - a BOOST converter, moving power from the output to the input. Then turn the main FET back on, giving a boost converter with a synchronous rectifier.

Cheers Terry