Reduce voltage from 220V DC to 30 - 50V DC without transformer
Producing 220V unregulated DC is actually making life harder for yourself.  Buck regulators aren't normally specified to take that high an input voltage.

If you are certain that nobody will be able to touch any live parts, then a simple capacitive dropper circuit may work.  But it's difficult to design properly without knowing the current that will be drawn by the motor.  If it's too high, then the thing may end up more bulky than just using a transformer.

In particular, you'd need to know the starting current of the motor, which is normally a lot higher than the running current.