US Patent 9705441 Divided phase AC synchronous motor controller

A circuit includes phase windings to receive alternating current (AC) line voltage. The circuit has a direct current (DC) power supply, a power switch circuit comprising at least one power switch, and a control circuit to turn off the power switch circuit when a rotor associated with the circuit is in an identified rotor position, rotor magnet polarity, or speed relative to the AC line voltage. The circuit also has at least one non-collapsing DC power supply component to prevent the DC power supply from collapsing when the at least one power switch is on and conducting during at least a portion of a cycle. One or more of the DC power supply, power switch circuit, and control circuit may be at a midpoint of the phase windings.