Using BLDC wheels is common on electric transport. A wheel is a multiphase motor, where each phase(coil) is separated from power source(battery) with some kind of transistor, driven by PWM-like signal. Almost like in the following illustration:
However, there also exists "recuperation". When you'll manage to press brakes - a motor should turn into a generator and charges battery again. But I've never seen any scheme or model of it.. You cannot simply push current in backwrd direction through fets.
How is this implemented? What approaches do you know (if there are many)?