3 phase full wave rectifier

[zaknabbit]

Hi EDA,

I'm doing a 3 wave fully controlled rectifier with 3 tca785's, the issue comes becouse of the control voltage, it should be connected to the pin 11 of the 3 tca785's but, every tca785 has its own ground point for his supply voltage and the control voltage has his own ground point too. And my question is, how could i isolate the control voltage for each tca785 to have them whith the same control voltage but it refered to each tca785 ground?

Salutes and thanks.

 

[lhademmor]

Either some optocoublers or some gate driver transformers (or one with 3 outputs), between the one controller and each TCA785 unit. But why using 3 phases and 3 tca devices ?, why not put the rectified of all phases into one tca785 ?

 

[zaknabbit]

The point is that the project is doing this with 3 phases, 3 sync voltages and 3 tca785. But using an optocoubler i wouldn't have the same control voltage not? i would turn on the transistor but i wouldn't replicate the v voltage in the another grounded circuit, or

 

[FvM]

You have already solved the issue one year ago, by using common control ground and trigger transformers. https://www.edaboard.com/threads/331187/

That seems to be the reasonable way. If you use separate grounds, e.g. because you want to save the trigger transformer, you can't avoid analog isolators for the control voltage.