I found a module which seems to have a rectifier and transistor bridge built-in. The module marking code is "SKiiP 13NEL0631". However, I couldn't find its datasheet. The closest one that I found is the SKIIP10NEC063T1. Datasheet: http://astronix.biz/datasheets/SKIIP10NEC063T1.pdf
which is a 1-phase bridge rectifier+3-phase bridge inverter.

Well, the thing is that I found that module in a treadmill controller which has a brushed DC motor (2 terminals). So, I didn't find a reason why using a 3-phase bridge inverter to control a single DC motor. I even tried to decode the circuit, but couldn't see something reasonable. So, I think that the datasheet that I found is wrong.

Basically my question is if it's possible somehow to use a 3-phase bridge inverter to drive a DC motor like that. I would also appreciate if you find a datasheet more reasonable for that module. I could also be wrong, and misunderstanting something.

 

It was quite common in the early days of CNC for 3phase bridge SCR controllers to control DC brushed motors.
You will notice at the bottom of the sheet they show the DC output.
It is a variation on the more common SCR 1 phase bridge used.
Max.