Hi


I am designing a 3 phase synchronous rectifier which must take in an AC input of max 100Hz and max peak voltage of 40 Volts and convert it into 25 Volts DC



My plan was to use the following stages in sequence

1) 3 phase synchronous rectifier (LT-4320 based)
https://www.digikey.com/catalog/en/partgroup/lt4320-demonstration-boards/41658
followed by

2) Power factor correction

3) Buck-boost converter (LT-8390)


Input will come from an alternator connected to an engine, who's rpm can be controlled.

Is the PFC correction stage necessary and how do i go about it ? There are some Demo circuits/boards that i found but they are all in the order of milli Amps

It needs to process 2.5KW!

 

Hi


I am designing a 3 phase synchronous rectifier which must take in an AC input of max 100Hz and max peak voltage of 40 Volts and convert it into 25 Volts DC



My plan was to use the following stages in sequence

1) 3 phase synchronous rectifier (LT-4320 based)
https://www.digikey.com/catalog/en/partgroup/lt4320-demonstration-boards/41658
followed by

2) Power factor correction

3) Buck-boost converter (LT-8390)


Input will come from an alternator connected to an engine, who's rpm can be controlled.

Is the PFC correction stage necessary and how do i go about it ? There are some Demo circuits/boards that i found but they are all in the order of milli Amps

It needs to process 2.5KW!

It seems like a 24V battery charger/ 100A. My suggestion would be the following:

1. since you have AC input, examine the case doing Full wave bridge with thyristors, so you can control the gating and get adjustable voltage output at 25V. Of course you will need a microcontroller for the regulation and gating.

2. Convert to DC Using high amperage diodes, charge up a bulk capacitor as input filter, and then examine the case of having a DC to DC Step down converter of 100A @ 25V you need.

3. in case you have lower than 37,5 AC peaked, the DC conversion will be below 25V DC, then you have to get into buck boost converters, sepic etc.so you can do both.