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Three phase PFC and digital power control?

Other Parts Discussed in Thread: UCD3138, UCD3138PFCEVM-026

Any suggestions on topologies for three phase PFC circuits suitable for control by eg the UCD3138? Is a three phase extension to the bridgeless converter design used in the UCD3138PFCEVM-026 feasible?

In the design I'm considering, the DC output from the PFC stage is used as the input to a ZVS H-bridge, thus my other post re availability of an evaluation board for a PSFB design. Not many answers coming back on that :-(

  • Paul,

    I am not certain what you mean when you say three phase PFC circuits. Do you mean you are using three phase power from the grid as your PFC input? If so, we did not do one of these designs although it might be possible.

    If however, by three phase PFC you mean a PFC topology similar to below, then yes:

    While we do not have sample code for a three-phase PFC, we do have sample code for a 2-phase interleaved PFC. It should not be too difficult to make modifications to the source code for a 3-phase PFC. Have you purchased the UCD3138PFCEVM-026 Evaluation module yet? This EVM is easily modified through two jumpers and a quick change in the source code for evaluation of this 2-phase interleaved PFC. This EVM might help to get you on your way.

    If you do already have the UCD3138PFCEVM-026, please send me an email at bvonk@ti.com and I can send you some updated EVM source-code that can easily be modified for the interleaved PFC configuration. Thanks for the question!

    Regards,

    Brandon Vonk 

  • Hi Brandon,

    it is indeed three phase from the grid that I was looking for. There are similarities to the single phase variants, and some parallels that can be drawn with the "two phase interleaved" approach also.

    The paper "The Essence of Three-Phase PFC Rectifier Systems Part 1" by Kolar and Friedli gives an excellent summary of the different approaches that can be used. Figure 18(b) in that paper shows a topology  that is suitable. I believe that a single UCD3138 would be able to implement the controller for a 3 phase PFC.

    I have asked our local distributors for price & availability for the evaluation modules, so will be back in touch when we get started on this.

    Following this PFC stage we are looking at using a ZVS full-bridge, thus my interest in availability of the other evaluation boards.

    regards,

     

    Paul T.

  • Hi Paul,

    I am interested in your application of a 3-phase (grid-connected) PFC.  Were you able to get something running?

    Thanks,

    Bill

  • Hello Bill,

    we haven't made any progress on this, and with our particular application, the benefit we would get turns out to be marginal (we are not connected to an outside grid), so we are not likely to be pursuing this further.

    Having said that, the lack of an application note / demo board etc for 3 phase systems seems to be a glaring omission in the market. You would think that a off-the-shelf controller implementing one of the various methodologies out there would be commercially viable.

    rgds,

    Paul T.