System and method for managing electrical power drawn from a vehicle alternator

1. A system for managing electrical power drawn from a vehicle alternator to supply power to an auxiliary system, the system comprising:

a controller configured to:

determine an output voltage (Valt) of the vehicle alternator;

perform a comparison of the output voltage (Valt) of the vehicle alternator to a threshold; and

adjust a power demanded by the auxiliary system from the vehicle alternator according to the result of the comparison to ensure that the power demanded by the auxiliary system can be supplied without drawing electrical power from a battery of the vehicle.

2. A system according to claim 1 , wherein the controller is configured to adjust a current drawn by the auxiliary system to adjust the power demanded by the auxiliary system.

3. A system according to claim 1 , wherein the controller is configured to switch off one or more loads of the auxiliary system to adjust the power demanded by the auxiliary system.

4. A system according to claim 1 wherein the controller is configured to adjust an operating mode of one or more loads of the auxiliary system to adjust the power demanded by the auxiliary system.

5. A system according to claim 1 , wherein the controller is configured to:

if the output voltage of the vehicle alternator is greater than the threshold, increase the power demanded by the auxiliary system;

if the output voltage of the vehicle alternator is less than the threshold, reduce the power demanded by the auxiliary system; or

if the output voltage of the vehicle alternator is equal to the threshold, maintain the power demanded by the auxiliary system.

6. A system according to claim 1 , wherein the system further comprises an auxiliary battery for supplying power to the auxiliary system.

7. A system according to claim 6 , wherein the controller is configured to:

if the output voltage of the vehicle alternator is greater than the threshold, adjust a supply of electrical power to the auxiliary battery to charge the auxiliary battery.

8. A system according to claim 6 , wherein the controller is configured to:

if the output voltage of the vehicle alternator is lower than the threshold, couple the auxiliary battery to one or more loads of the auxiliary system such that the one or more loads of the auxiliary system are at least partially powered by the auxiliary battery.

9. A system according to claim 1 , wherein the controller comprises a proportional-integral controller.

10. A system according to claim 1 , wherein the system further comprises a buck-boost converter coupled to an output of the vehicle alternator and operative to provide an electrical power supply to the auxiliary system.

11. A method for managing electrical power drawn from a vehicle alternator to supply power to an auxiliary system, the method comprising:

determining an output voltage of the vehicle alternator;

performing a comparison of the output voltage of the vehicle alternator to a threshold; and

adjusting a power demanded by the auxiliary system from the vehicle alternator according to the result of the comparison to ensure that the power demanded by the auxiliary system can be supplied without drawing electrical power from a battery of the vehicle.

12. A method according to claim 11 , wherein adjusting the power demanded by the auxiliary system comprises adjusting a current drawn by the auxiliary system.

13. A method according to claim 11 , wherein adjusting the power demanded by the auxiliary system comprises switching off one or more loads of the auxiliary system.

14. A method according to claim 11 , wherein adjusting the power demanded by the auxiliary system comprises adjusting an operating mode of one or more loads of the auxiliary system.

15. A method according to claim 11 , wherein adjusting the power demand of the auxiliary system comprises:

if the output voltage of the vehicle alternator is greater than the threshold, increasing the power demanded by the auxiliary system;

if the output voltage of the vehicle alternator is less than the threshold, reducing the power demanded by the auxiliary system; or

if the output voltage of the vehicle alternator is equal to the threshold, maintaining the power demanded by the auxiliary system.

16. A system according to claim 1 , wherein the auxiliary system is an electrically powered temperature control system for maintaining a temperature within a goods space of a host vehicle at a predetermined temperature or within a predetermined temperature range.

17. A method according to claim 11 , wherein the auxiliary system is an electrically powered temperature control system for maintaining a temperature within a goods space of a host vehicle at a predetermined temperature or within a predetermined temperature range.

18. A system according to claim 1 , wherein the controller is configured to adjust the power demanded by the auxiliary system by at least one of:

switching off one or more loads of the auxiliary system; and

adjusting an operating mode of the one or more loads of the auxiliary system,

wherein the one or more loads of the auxiliary system include one or more of a compressor, a pump, and a heater of a temperature control system.

19. A method according to claim 11 , wherein adjusting the power demanded by the auxiliary system includes at least one of:

switching off one or more loads of the auxiliary system; and

adjusting an operating mode of the one or more loads of the auxiliary system,

wherein the one or more loads of the auxiliary system include one or more of a compressor, a pump, and a heater of a temperature control system.

20. A system according to claim 1 , wherein the controller is configured to adjust the power demanded by the auxiliary system from the vehicle to meet a power output capability of the vehicle alternator, to ensure that the power demanded by the auxiliary system can be supplied without drawing electrical power from the battery of the vehicle.