Apparatus for transferring energy using power electronics and machine inductance and method of manufacturing same

1. An apparatus comprising:

a first bi-directional DC-to-AC inverter coupled to a first DC bus;

a first electromechanical device coupled to the first bi-directional DC-to-AC inverter;

a bi-directional DC-to-DC converter coupled between the first DC bus and a second DC bus;

a first energy storage device coupled to the second DC bus;

a second bi-directional DC-to-AC inverter coupled to the first energy storage device; and

a charge bus coupled to the second bi-directional DC-to-AC inverter through at least one winding of a second electromechanical device, the charge bus configured to receive a charging voltage from an external power source and supply the charging voltage to the second bi-directional DC-to-AC inverter.

2. The apparatus of claim 1 further comprising a controller configured to:

selectively control switching of the second bi-directional DC-to-AC inverter to:

convert a DC voltage on the second DC bus into an AC voltage suitable for supplying to the second electromechanical device; and

convert a charging voltage supplied to the first electromechanical device from the external power source into a DC voltage suitable for charging the first energy storage device; and

selectively control switching of the first bi-directional DC-to-AC inverter to:

convert a DC voltage on the first DC bus into an AC voltage suitable for supplying to the first electromechanical device; and

convert an AC voltage of the first electromechanical device to a DC voltage suitable for delivery to the first DC bus.

3. The apparatus of claim 2 wherein the controller is further configured to selectively control switching of the bi-directional DC-to-DC converter to convert the DC voltage on the first DC bus to the DC voltage suitable for charging the first energy storage device.

4. The apparatus of claim 1 further comprising a second energy storage device coupled to the first DC bus.

5. The apparatus of claim 4 wherein the second energy storage device comprises an ultracapacitor; and

wherein the first energy storage device comprises a battery having a lower voltage than the ultracapacitor.

6. The apparatus of claim 1 wherein the charge bus comprises:

a first conductor coupled to the second bi-directional DC-to-AC inverter and the external power source; and

a second conductor coupled to the second electromechanical device and the external power source.

7. The apparatus of claim 1 wherein the first electromechanical device comprises a traction motor; and

wherein the second electromechanical device comprises an alternator.

8. A method of manufacturing comprising:

providing a first energy storage device;

coupling a low-voltage side of a bi-directional DC-to-DC converter to the first energy storage device;

coupling a high-voltage side of the bi-directional DC-to-DC converter to a first DC bus;

coupling a first bi-directional DC-to-AC inverter to the first DC bus;

coupling a first electromechanical device to the first bi-directional DC-to-AC inverter;

coupling a second bi-directional DC-to-AC inverter in parallel with the first energy storage device across a second DC bus;

coupling a second electromechanical device to the second bi-directional DC-to-AC inverter; and

coupling a charge bus to the second bi-directional DC-to-AC inverter and an external power source.

9. The method of claim 8 further comprising coupling the charge bus to the second bi-directional DC-to-AC inverter through at least one winding of the second electromechanical device.

10. The method of claim 8 further comprising electrically coupling a controller to the first and second bi-directional DC-to-AC inverters and to the bi-directional DC-to-DC converter to selectively control switching thereof.

11. The method of claim 10 further comprising coupling a second energy storage device to the first DC bus, the second energy storage device having a higher voltage than the first energy storage device.

12. A charging system comprising:

an external power source; and

a vehicle comprising:

a first DC bus;

a first bi-directional DC-to-AC voltage inverter configured to invert an AC voltage of a first electromechanical device to a first DC voltage and supply the first DC voltage to the first DC bus;

a bi-directional DC-to-DC voltage converter coupled to the first DC bus and configured to convert the first DC voltage to a second DC voltage and supply the second DC voltage to a second DC bus;

a second bi-directional DC-to-AC voltage inverter coupled in parallel to a first energy storage device across the second DC bus, the second bi-directional DC-to-AC voltage inverter configured to invert an AC voltage of a second electromechanical device to a DC voltage suitable for charging the first energy storage device;

a charge bus configured to receive a charging voltage from the external power source and supply the charging voltage to the second electromechanical device; and

a controller configured to selectively control switching of the first bi-directional DC-to-AC voltage inverter, the second bi-directional DC-to-AC voltage inverter, and the bi-directional DC-to-DC voltage converter.

13. The charging system of claim 12 further comprising an internal combustion engine coupled to the second electromechanical device.

14. The charging system of claim 12 wherein the external power source comprises an AC power source.

15. The charging system of claim 12 wherein the external power source comprises a DC power source.

16. The charging system of claim 12 further comprising a second energy storage device configured to supply electrical energy to the first DC bus, the second energy storage device having a higher voltage than the first energy storage device.

17. The charging system of claim 16 wherein the controller is further configured to selectively control switching of the bi-directional DC-to-DC voltage converter to:

convert a DC voltage on the first DC bus into a DC voltage suitable for charging the second energy storage device; and

convert a DC voltage on the second DC bus into a DC voltage suitable for charging the first energy storage device.

18. The charging system of claim 12 wherein the second bi-directional DC-to-AC voltage inverter comprises a three-phase DC-to-AC voltage inverter having a plurality of half-phase modules; and

wherein the controller is further configured to control switching of the plurality of half-phase modules to cause the second bi-directional DC-to-AC voltage inverter to operate as a two-phase circuit.

19. The charging system of claim 12 further comprising a rectifier coupled between the charging bus and the external power source.

20. The charging system of claim 19 wherein the rectifier is located off-board the vehicle.