Electric drive with electronically scalable reconfigurable winding

A stator phase circuit for an electric machine, comprising:na phase winding circuit for a single phase comprising a plurality of series coupled sub-winding circuits, each sub-winding circuit comprising only one respective sub-winding coupled in parallel across a respective first controllable switch of only the corresponding sub-winding circuit, wherein respective winding turn ratios of the respective sub-windings are selectively combinable to provide a plurality of effective winding turn ratios of the phase winding circuit for the single phase based on at least one of the series coupled sub-winding circuits in circuit only when the respective first controllable switch is open; anda half-bridge respective only to the phase winding circuit for the single phase and coupled in series with one of the series coupled sub-winding circuits.

A multi-phase winding circuit for an electric machine, comprising:na plurality of phase winding circuits, each respective phase winding circuit for a respective single phase and comprising a plurality of series coupled sub-winding circuits, each respective sub-winding circuit comprising a respective first controllable switch coupled in series with only one respective sub-winding and a respective second controllable switch of only the corresponding sub-winding circuit coupled in parallel across the corresponding series coupled first controllable switch and sub-winding, wherein the first and second controllable switches are bi-directional switches operable in open and closed states, and wherein the respective first and second controllable switches of each sub-winding circuit are never both in the open and closed states simultaneously, and wherein respective winding turn ratios of the respective sub-windings are selectively combinable to provide a plurality of effective winding turn ratios of the phase winding circuit for the single phase based on at least one of the series coupled sub-winding circuits in circuit only when the respective second controllable switch is open; anda plurality of half bridges, each half-bridge respective only to one of the phase winding circuits for the respective single phase and coupled in series with one of the series coupled sub-winding circuits.

Method of operating an electric machine comprising a phase winding circuit having a plurality of series coupled sub-winding circuits, each respective sub-winding circuit for a respective single phase and comprising a respective first controllable switch coupled in series with only one respective sub-winding and a respective second controllable switch of only the corresponding sub-winding circuit coupled in parallel across the corresponding series coupled first controllable switch and sub-winding, the method comprising:nselecting an effective winding turn ratio for the phase winding circuit comprising a series combination of at least one of said sub-windings in circuit only when the respective second controllable switch is open, wherein respective winding turn ratios of the respective sub-windings are selectively combinable to provide the selected effective winding turn ratio of the phase winding circuit for the respective single phase; andcontrolling each switch of the phase winding circuit to provide the effective turn ratio.