Is it possible to convert 3 Phase 220V to 110V without use of a transformer?
Triac based light dimmers do this.

Varying the firing angle of the gate results in a reduced RMS output voltage. The output from this can be rectified and filtered however extreme caution should be exercised because the circuit has no galvanic isolation from the Neutral/Active lines and cannot be earth referenced if ELCB's are intalled.