High power-density, high efficiency, non-permanent magnet electric machine

1. An electrical circuit coupled to a non-permanent magnet electric machine comprising:

an alternating current (AC) source configured to apply an AC voltage to a first set of poles of a stator; and

a direct current (DC) source configured to apply a DC voltage to a second set of poles of the stator;

wherein the second set of poles has fewer poles than the first set of poles; and

wherein the first set of poles and the second set of poles are formed from a single fractional-slot concentrated winding.

2. The electrical circuit of claim 1 comprising a first wye-connection comprising the first set of poles.

3. The electrical circuit of claim 2 wherein the first wye-connection is a first three-phase circuit that comprises the first set of poles in one phase winding of the first three-phase circuit.

4. The electrical circuit of claim 2 comprising a second wye-connection comprising the second set of poles.

5. The electrical circuit of claim 4 wherein the second wye-connection is a second three-phase circuit that comprises the second set of poles in one phase winding of the second three-phase circuit.

6. The electrical circuit of claim 1 wherein the stator comprises twelve slots.

7. The electrical circuit of claim 1 wherein, when the AC voltage is applied to the first set of poles, a first pole-number (P 1 ) of the stator is excited, and when the DC voltage is applied to the second set of poles, a second pole-number (P 2 ) is excited in addition to the excitation from the first voltage applied to the first set of poles.

8. The electrical circuit of claim 7 wherein a number of rotor poles (P 3 ) driven by the electrical circuit are determined by the equation P 3 =(P 1 +P 2 )/2.

9. The electrical circuit of claim 7 wherein a number of rotor poles (P 3 ) driven by the electrical circuit are determined by the equation P 3 =(P 1 −P 2 )/2.

10. The electrical circuit of claim 1 wherein the first set of poles includes the second set of poles.

11. An electrical circuit for a synchronous reluctance electric machine comprising:

a pair of balanced wye-connections for a single fractional-slot concentrated winding of a stator, the pair of wye-connections comprising:

a first wye-connection comprising a first set of terminals of the stator, wherein the first wye-connection includes a first three-phase circuit that comprises the first set of terminals in one phase winding of the first three-phase circuit; and

a second wye-connection comprising a second set of terminals, wherein the second wye-connection is a second three-phase circuit that comprises the second set of terminals in one phase winding of the second three-phase circuit

an alternating current (AC) power source coupled to the first set of terminals of the stator; and

a direct current (DC) power source coupled to the second set of terminals of the stator;

wherein the single fractional-slot concentrated winding is configured to have a first pole number and a second pole number based on the first set of terminals and the second set of terminals, respectively, with the first wye-connection representing the first pole number and the second wye-connection representing the second pole number.

12. The electrical circuit of claim 11 wherein the first and second sets of terminals are arranged such that the second number of poles (P 2 ) is simultaneously excited by both the AC power source from the first set of terminals and by the DC power source from the second set of terminals.

13. The electrical circuit of claim 11 wherein a number of rotor poles (P 3 ) driven by the electrical circuit are determined by the equation P 3 =(P 1 +P 2 )/2.

14. The electrical circuit of claim 11 wherein a number of rotor poles (P 3 ) driven by the electrical circuit are determined by the equation P 3 =(P 1 −P 2 )/2.

15. The electrical circuit of claim 11 wherein the first set of terminals includes the second set of terminals.

16. A method of fabricating an electrical circuit for a synchronous reluctance electric machine comprising:

forming a pair of balanced wye-connections for a single fractional-slot concentrated winding of a stator, wherein forming the pair of wye-connections comprises:

forming a first three-phase circuit having a first wye-connection comprised of a first set of poles of the stator, wherein the first wye-connection includes the first set of poles in one phase winding of the first three-phase circuit; and

forming a second three-phase circuit having a second wye-connection comprised of a second set of poles of the stator, wherein the second wye-connection includes the second set of poles in one phase winding of the second three-phase circuit

coupling an alternating current (AC) power source to the first set of poles of the stator; and

coupling a direct current (DC) power source to the second set of poles of the stator, wherein a number of the second set of poles is less than a number of the first set of poles.

17. The method of claim 16 comprising:

arranging the first set of poles and the second set of poles such that the second number of poles (P 2 ) is simultaneously excitable by:

1) the AC power source from the first set of poles; and

2) the DC power source from the second set of poles.

18. The method of claim 16 wherein the first set of poles includes the second set of poles.