Sound of regenerative braking.

So, I hear a sound when regen is set to standard and sound is only heard when car is about to come to stop, usually below the speed of 10 mph. If I start regen at 50 mph, I do not hear the sound until car has slowed down below 10 mph and about to come to a full stop. I don't know how to best describe it but almost sounds to me like motor/inverter is unwinding? I felt that it was significantly less noticeable when regen was set to low. Anyone else experience this. I have not noticed this on acceleration.

The sound has not bothered be personally and I have only noticed it on some really early morning drives to work when it is really really quiet (no traffic) and I am not in mood to listen to radio. Just wanted to make sure that I do not have to worry about motor/inverter.