72VDC 5Amp Power Supply for Battery Charging

Posted by: Ishan on 10/11/2018

Hi,
We have to design 72VDC, 5Amp power supply for battery charging purpose.
It doesn't matter if its isolated or non isolated, no PFC required.
I have referred the DER-547 application note for HiperPFS-4 but unable to get idea about how to set the output voltage.
It would be great if someone can help me out with this.

Comments

Hi Ishan,

Perhaps the following reference design can be a good starting point for you:

https://ac-dc.power.com/design-support/reference-designs/design-examples/der-472-300-w-non-pfc-stage-forward-power/

-PI-ODO

Hi PI-ODO,

Thanks for the response..!!!
I am more interested in DER-547 which is a transformer less design and utilizes Hiper-PFS4.
I guess I can change the feedback resistor network to change the output to 72VDC.
But you are suggesting DER-472, so is that the case where DER-547 [Hiper-PFS4] is a PFC Front End and cannot be used a power supply ?

Thanks,
Ishan

Hi Ishan,

You are welcome! As you noted, DER-547 is intended as a PFC Front End (100 VAC – 300 VAC Input; 440 VDC Output) and works as a *boost* converter to provide a high-voltage DC bus. Typically, a subsequent power supply stage is then used to generate the desired lower voltages.

-PI-ODO

Hello PI,

I have started looking at the reference design suggested by you. The input voltage range is 90-132 VAC but I need universal input range of 86-265 VAC. I see that mov RV1, cap C3 and C4 limit the input range, please let me know if there is any other component that needs attention.
One more point is that I need 72VDC 5Amp (Main Output) and 12V 1/2Amp (Standby Output).
But I am unable to find the output voltage equation in the HiperTFS2 datasheet.

Request you to provide your inputs on above points.

Thanks..!!!

Hi Ishan,

Here is the design with universal input voltage range.

https://ac-dc.power.com/design-support/reference-designs/design-examples/der-484-300-w-forward-power-supply/

https://ac-dc.power.com/sites/default/files/PDFFiles/der484.pdf

Standby output is a separate fly-back converter, so it is independent operation from main converter.

Please use PIxls spreadsheet to design your transformers
https://ac-dc.power.com/design-support/pi-expert/pi-expert-online/
https://piexpertonline.power.com/site/login

Regards,
PI-NANO

Hello PI,
Thanks for the update..!!!
What if I don't need PFC stage of HiperPFS-3 ?
Can I directly input 86-265 VAC at the B+ and B- terminals in the second stage comprising HiperTFS-2 ?
Please let me know.

Thanks..!!!

Hi Ishan,

No you can connect the AC input directly on B+ and B-.

Regards,
PI-NANO