UCC28951: Full Bridge Rectifier (with Diodes or MOSFTEs) with UCC28951 for 450 Vout 5kW converter

Hello,

Your inquiry is under review and I will get back to you shortly.

Regards,

Hi is this good idea to proceed PSFB for high voltage output,because of ringing at secondary side leads voltage overshoots?even snubber is not feasible for high voltage levels ?correct me if i am wrong

Any reason why you want 450V in and 450V out? Why is PFC involved? Can you please share more system level info?

Hi,

Requirement is 420V EV Battery charging, usually practice is 230V ,bridge rectifier followed by Boost PFC I400V DC) then isolated DC to DC

Thank you

venkatesh B

If the secondary side ringing is a concern, you may want to consider full bridge LLC topology. Since you have fixed Vin (after PFC) and Vout, LLC may be a more suitable topology for your application.

can i able to use same UCC28950 PSFB IC for LLC operation since hardware already done

No you cannot use UCC28950 as a LLC controller.

ok sir,i have made hardware and facing this ripple issue ,what shall i do now?

Please share the waveform and schematic so we can review and provide inputs.

i have attached the schematic complete file.

Attached few waveforms of Input side voltage and Input current,output voltage and output current

please help me to resolve the issue 

Thanks 

venkatesh B

Received. We will review it and let you know if there is any clarification needed.

please leave your email address here.

Hi

venkatesh.b@flowtrik.com

Thank you

Hi ningtan any possibilities? 

We will need more time. Please be patient.

ok thank you

anticipating your reply

The whole system is a unidirectional isolated AC/AC consisting of PFC—Isolating DC/DC—DC/AC capable of changing frequency and output current.

The first main principle is that every stage should be controlled by its own IC, with a general supervising uC. Before switching to a dedicated controller like C2000

The system requirement is to have a 9kW DC/DC converter capable of receiving 450V in input and maintaining 450V in output. Since UCC28951 has a synch function, I thought it'd have been a good idea to split that power into 2 modules.

as far as I know synchronizing LLC is a mess,  loss of the PSFB ZVS is a mess. Plain FB ICs with synch option is hard to find

also I saw the design with two active FB with an output snubber https://www.ti.com/tool/PMP6712

as well as in one from the competitor, using the same approach to mitigate the ringing through the active snubbing. I don't know if I can post here the links fir external resources

As a final remark, I kindly ask an assistance; I'd like to ask whether it's safer to go with modular PSFB or a single LLC. (holding in mind that the first prototype should be implemented with ICs)

Hi densys kovalov,

Thank you for reviewing and for detailed explanation

current design i will implement the active snubbers with logic controller IC

i would like to go for LLC in the Next design since it would be nice to cater all this challenge

Thank you

venkatesh 

Can you confirm if any help is needed here? If so, we can communicate via email since you deleted the schematic post.

thanks,

Hi ning tan,

A of now, i freeze the circuit and started testing in progress

It would be great and pleasure if any support can be given for transformer design(for schematic voltage overshoot were ok,using higher voltage1200V Sic diodes and no board changes like new schematic,layout were allowed as of now for me)

Problem now is transformer getting heated up gradually,it is functional level ok and handle 3.3KW of power but thermally not stable

attached the calculation sheet which i used, kindly do the needful please

Thank you so much for your support

3.5KW_trafo.xlsx

Area Product design approach_ref_Prof_Ramnarayanan.pdf

Hi ning tan,

how are you

Thanks

Venkatesh,

I am not sure what kind of design support you need. You can refer to our calculator for key transformer parameters.

Thanks,

Ning