System for supplying propulsion energy from an auxiliary drive and method of making same

1. A propulsion system comprising:

an energy system for supplying power to an electric drive, the energy system comprising:

a bi-directional boost converter coupled to a direct current (DC) link, the bi-directional boost converter comprising a plurality of input channels; and

a first energy storage device coupled to a first input channel of the bi-directional boost converter via a DC bus;

an auxiliary system coupled to the energy system, the auxiliary system comprising:

an auxiliary energy source;

an auxiliary load; and

an auxiliary load controller coupled to the auxiliary energy source and to the auxiliary load; and

a system controller configured to:

determine an amount of propulsion power desired to be supplied to the electric drive;

receive feedback information of the DC link from one of a current sensor and a voltage sensor;

determine, based on the feedback information, a capability of the first energy storage device to supply the amount of propulsion power to the DC link;

determine a power difference between the amount of propulsion power desired to be supplied to the electric drive and an amount of power capable of being supplied by the first energy storage device;

cause the auxiliary load controller to reduce a power draw of the auxiliary load from the auxiliary energy source by at least an amount equal to the power difference; and

cause the bi-directional boost converter to boost a voltage supplied by the auxiliary energy source based on the reduction in power draw and to supply the boosted voltage to the DC link.

2. The propulsion system of claim 1 wherein the system controller is configured to cause the auxiliary load controller to stop the power draw of the auxiliary load from the auxiliary energy source.

3. The propulsion system of claim 1 wherein the auxiliary energy source comprises:

an internal combustion engine;

an alternator coupled to the internal combustion engine; and

a rectifier coupled to the alternator and to a second input channel the bi-directional boost converter.

4. The propulsion system of claim 3 wherein the auxiliary load comprises an alternating current (AC) load coupled to receive AC energy from the alternator.

5. The propulsion system of claim 3 wherein the auxiliary load comprises a DC load coupled to receive DC energy from the rectifier.

6. The propulsion system of claim 5 wherein the DC load comprises a DC-AC inverter coupled to an AC load.

7. The propulsion system of claim 1 wherein the auxiliary energy source comprises a second energy storage device coupled to a second input channel the bi-directional boost converter; and

wherein the auxiliary load comprises a DC load coupled to receive DC energy from the second energy storage device.

8. The propulsion system of claim 1 further comprising a coupling device coupled to the DC link and to the auxiliary system; and

wherein the system controller is configured to control the coupling device to selectively couple the DC link to the auxiliary system to cause a transfer of power from the DC link to the auxiliary system to bypass the bi-directional boost converter.

9. The propulsion system of claim 8 wherein the coupling device comprises:

one of a power semiconductor device and a contactor; and

a resistor.

10. The propulsion system of claim 1 wherein the energy system further comprises a first coupling device configured to selectively couple the auxiliary system to the first input channel.

11. The propulsion system of claim 10 wherein the auxiliary system is coupled to a second input channel of the bi-directional boost converter; and

wherein the energy system further comprises:

a second energy storage device coupled to a third input channel of the bi-directional boost converter; and

a second coupling device configured to selectively couple the first input channel to the third input channel.

12. The propulsion system of claim 1 wherein the first energy storage device comprises one of a battery, an ultracapacitor, and a flywheel.

13. A method of assembling a propulsion energy system, the method comprising:

coupling an energy system to a direct current (DC) link, the energy system comprising:

a multi-channel bi-directional boost converter coupled to the DC link; and

an energy storage device coupled to a first input channel of the bi-directional boost converter via a DC link;

coupling an auxiliary system to the energy system, the auxiliary system comprising:

an energy source;

a load controller coupled to the energy source; and

a load coupled to the load controller;

coupling a motor to the DC link;

coupling a controller to the energy system and to the auxiliary system; and

configuring the controller to:

determine an amount of additional power needed by the energy system, beyond that available by the energy system, to supply a desired power to the motor;

cause a reduction in power draw of the load of the auxiliary system from the energy source of the auxiliary system based on the amount of additional power needed by the energy system; and

cause the DC link to receive a boosted voltage from the multi-channel bi-directional boost converter based on the reduction in power draw.

14. The method of claim 13 configuring the controller comprises configuring the controller to cause the load controller to halt all power draw by the load.

15. The method of claim 13 wherein the energy source of the auxiliary system comprises a heat engine.

16. A vehicle system comprising:

a direct current (DC) energy storage device coupled to a first channel of a bi-directional DC-DC boost converter;

an auxiliary energy source coupled to a first load controller and to a second channel of the bi-directional DC-DC boost converter;

a first auxiliary load coupled to the first load controller, the first auxiliary load comprising a non-rechargeable device; and

a vehicle system controller programmed to:

reduce a load energy supplied by the auxiliary energy source to the first auxiliary load from a first energy value to a second energy value; and

boost at least a portion of the reduced energy via the bi-directional DC-DC boost converter for supply thereof to a DC link.

17. The vehicle system of claim 16 wherein the vehicle system controller is further programmed to:

reduce a load energy supplied by the auxiliary energy source during an acceleration mode; and

return the load energy supplied by the auxiliary energy source to the first energy value following the acceleration mode.

18. The vehicle system of claim 16 wherein the auxiliary energy source comprises a heat engine coupled to an alternator; and

wherein the first auxiliary load comprises an alternating current (AC) load coupled to receive AC energy from the alternator.

19. The vehicle system of claim 16 further comprising:

a second load controller coupled to the auxiliary energy source;

a second auxiliary load coupled to the second load controller; and

wherein the vehicle system controller is further programmed to:

prioritize reduction of load energy such that a reduction of load energy supplied by the auxiliary energy source to the first auxiliary load occurs prior to a reduction of load energy supplied by the auxiliary energy source to the second auxiliary load.

20. The vehicle system of claim 16 further comprising a coupling device configured to couple energy supplied by the auxiliary energy source to energy supplied by the DC energy storage device.

21. The vehicle system of claim 16 wherein, in reducing the load energy supplied by the auxiliary energy source to the first auxiliary load from the first energy value to the second energy value, the vehicle system controller is further programmed to reduce the load energy supplied by the auxiliary energy source to the first auxiliary load by an amount equal to an amount of additional power needed by the DC bus, beyond that available by the DC energy storage device, to supply a desired power to a motor connected to the DC bus.