ENERGY RECAPTURE FOR AN INDUSTRIAL VEHICLE

• US 20080290842A1
• Filed: 05/21/2008
• Published: 11/27/2008
• Est. Priority Date: 05/21/2007
• Status: Active Grant

• Current Assignee: Hyster-Yale Materials Handling Incorporated (Nacco Industries Incorporated)
• Original Assignee: NMHG Oregon, LLC
• Inventors: Rowley, John, Davis, James W., Fitzsimmons, Alan H., McGoldrick, Kevin J., Neil, Robert M.
• Granted Patent: US 8,022,663 B2
• Time in Patent Office: Days
• US Class Current: 320/166
• CPC Class Codes: B60L 50/40 using propulsion power supplied by capacitors
• CPC Class Codes: B60L 7/24 with additional mechanical or electromagnetic braking
• CPC Class Codes: H02J 7/1423 with multiple batteries
• CPC Class Codes: H02J 7/345 using capacitors as storage or buffering devices
• CPC Class Codes: Y02T 10/70 Energy storage systems for electromobility, e.g. batteries

Abstract

A system for capturing regenerative energy includes a battery configured to provide power for a traction motor and other operations of a vehicle and a capacitor connected to the battery. An auxiliary motor is configured to operate as a generator during a regenerative energy operation. The system further includes a controller configured to direct the regenerative energy to the capacitor during the regenerative energy operation and discharge the capacitor to provide power to the traction motor or for the other operations of the vehicle.

Claims

1. An energy recapture system comprising:

a capacitor;

a battery connected in parallel to the capacitor in an electrical circuit; and

a controller configured to monitor a state of charge of the capacitor and switch the battery out of the electrical circuit during a regenerative energy transfer event of a vehicle.

2. The energy recapture system according to claim 1 wherein the regenerative energy transfer event comprises lowering a load, a potential energy of the load converted to regenerative energy by a hoist motor electrically connected to the energy recapture system.

3. The energy recapture system according to claim 1 wherein the regenerative energy transfer event comprises decelerating the vehicle, a kinetic energy of the vehicle converted to regenerative energy by a traction motor electrically connected to the energy recapture system.

4. The energy recapture system according to claim 1 wherein the battery is a lead acid battery and wherein the capacitor is a high capacity ultra-capacitor.

5. The energy recapture system according to claim 1 further comprising:

a battery contactor configured to switch out the battery while the capacitor is being charged and discharged.

6. The energy recapture system according to claim 5 further comprising:

a capacitor contactor configured to switch out the capacitor during a capacitor pre-charge event and a capacitor overcharge event.

7. The energy recapture system according to claim 6 wherein the capacitor pre-charge event comprises pre-charging the capacitor to a voltage approximately equal to that of the battery to avoid an excessive in-rush of power to the capacitor.

8. The energy recapture system according to claim 1 wherein the battery and the capacitor are integrated into a unitary power module comprising a single negative terminal.

9. The energy recapture system according to claim 8 wherein the unitary power module further comprises a first positive terminal connected to the capacitor and a second positive terminal connected to the battery.

10. The energy recapture system according to claim 1 wherein the state of charge is monitored according to a measured capacitor voltage.

11. A system for capturing regenerative energy comprising:

a battery configured to provide power for a traction motor and other operations of a vehicle;

a capacitor connected to the battery;

an auxiliary motor configured to operate as a generator during a regenerative energy operation; and

a controller configured to;

direct the regenerative energy to the capacitor during the regenerative energy operation; and

discharge the capacitor to provide power to the traction motor or for the other operations of the vehicle.

12. The system according to claim 11 wherein the auxiliary motor is a hoist motor configured to raise and lower a load and wherein the regenerative energy operation comprises lowering the load.

13. The system according to claim 11 wherein the capacitor is connected to the battery in parallel.

14. The system according to claim 11 wherein the controller is further configured to:

switch the battery out of a vehicle electrical circuit;

determine a state of charge of the capacitor during the regenerative energy operation; and

switch the battery back into the vehicle electrical circuit when the state of charge exceeds a maximum allowable capacitor charge limit voltage threshold value.

15. The system according to claim 14 wherein the controller is further configured to:

switch the capacitor out of the vehicle electrical circuit when the state of charge exceeds the maximum allowable capacitor charge limit voltage threshold value to avoid overcharging of the capacitor during the regenerative energy operation.

16. The system according to claim 15 wherein the capacitor is switched out of the vehicle electrical circuit substantially simultaneously as the battery is switched in.

17. The system according to claim 15 wherein the controller is further configured to:

detect a vehicle electrical circuit voltage that is lower than a begin energy recapture limit value;

switch the capacitor back into the vehicle electrical circuit; and

switch the battery back out of the vehicle electrical circuit.

18. The system according to claim 14 wherein the controller is further configured to:

direct the regenerative energy to power concurrent operations of the vehicle during the regenerative energy operation.

19. The system according to claim 18 wherein the controller is further configured to:

charge the battery with any regenerative energy in excess of that used to power the concurrent operations.

20. The system according to claim 14 wherein the controller is further configured to:

detect a vehicle electrical circuit voltage that is higher than the maximum allowable capacitor charge limit voltage threshold value; and

direct the regenerative energy away from the capacitor and toward the battery.

21. The system according to claim 11 wherein the controller is further configured to:

monitor a change in battery voltage; and

adjust a minimum allowable capacitor discharge threshold value according to the change in battery voltage to control when the capacitor ceases to discharge.

22. A regenerative power module for a vehicle comprising:

a housing;

a capacitor configured to store regenerative power;

a battery connected to the capacitor in parallel, wherein the battery and the capacitor are located within the housing; and

a positive external terminal of the housing connected to the battery and the capacitor.

23. The regenerative power module according to claim 22 wherein the housing is configured to fit within a battery compartment space of the vehicle, and wherein the positive external terminal is configured to connect the regenerative power module to a vehicle electrical circuit.

24. The regenerative power module according to claim 23 further comprising:

a controller configured to switch the battery out of the vehicle electrical circuit when regenerative energy is being transmitted to the regenerative power module via the positive external terminal.

25. The regenerative power module according to claim 23 further comprising:

a controller configured to switch the capacitor out of the vehicle electrical circuit when a capacitor charge limit is exceeded.

26. The regenerative power module according to claim 23 further comprising:

a third external terminal connected to a vehicle key switch, wherein the key switch is configured to switch the battery out of the vehicle electrical circuit.

27. The regenerative power module according to claim 22 wherein the housing comprises a single negative external terminal and a plurality of positive external terminals.

28. The regenerative power module according to claim 22 wherein a second positive external terminal is configured to receive power from an external battery charger.