"Solar panels are already designed WITH a "blocking diode"
They must have somehow fell off on mine. I had to install my own schottky. Manufacturer said so.
"high power/high torque stepper motors (all PWM DC voltage by the way)"
You think there wasn't any EMI protection in those controllers? Check the schematic.
"Not once has there been any "series or parallel inductors" involved at the motors or in the motor drive electronics."
The motor winding IS the inductor
"at a speed faster than you can run"
LOL I haven't ran in over 20 years, unless I need to get to the john