Patent ID: 8207699

Claim:
An alternating current (AC) motor control system arranged to control a target AC motor, the target AC motor arranged to receive a three phase AC power, the target AC motor having: a first winding, a first end of the first winding arranged to be coupled to a first phase of the three phase AC power; a second winding, a first end of the second winding arranged to be coupled to a second phase of the three phase AC power; and a third winding, a first end of the third winding arranged to be coupled to a third phase of the three phase AC power, the AC motor control system comprising: a control unit; a cycloconverter functionality; a phase control functionality; and a semiconductor switching unit comprising a plurality of electronically controlled semiconductor switches each independently responsive to said control unit, said plurality of electronically controlled semiconductor switches comprising: a first pair of anti-parallel connected thyristors, a first end of said first pair arranged for connection to a second end of the first winding, and a second end of said first pair arranged for connection to the third phase of the three phase AC power; a second pair of anti-parallel connected thyristors, a first end of said second pair arranged for connection to a second end of the second winding, and a second end of said second pair arranged for connection to the first phase of the three phase AC power; and a third pair of anti-parallel connected thyristors, a first end of said third pair arranged for connection to a second end of the third winding, and a second end of said third pair arranged for connection to the second phase of the three phase AC power, said control unit arranged to modulate the conduction period of said first pair, said second pair and said third pair responsive to a selectable one of said phase control functionality and said cycloconverter functionality.