Hybrid energy management system

• US 8,297,392 B2
• Filed: 09/24/2010
• Issued: 10/30/2012
• Est. Priority Date: 09/25/2009
• Status: Expired due to Fees

• Current Assignee: Caterpillar Incorporated
• Original Assignee: Caterpillar Incorporated
• Inventors: Treichel, Benjamin A., Collins, David L., Post, Stephen Eric
• Primary Examiner(s): Phan, Hau
• Application Number:
  US12/889,643
• Publication Number:
  US 20110073392A1
• Time in Patent Office: 767 Days
• Field of Search: 180/65.31, 180/65.1, 180/65.51, 180/65.8, 180/216, 318/143, 318/466, 318/125, 318/370
• US Class Current: 180/65.31
• CPC Class Codes: E02F 9/123 Drives or control devices specially adapted therefor E02F9/125 and E02F9/128 take precedence
• CPC Class Codes: E02F 9/2075 of the hybrid type for vehicles in general B60W20/00
• CPC Class Codes: E02F 9/2217 with energy recovery arrangements, e.g. using accumulators, flywheels

Abstract

A hybrid energy management system that estimates the net regenerative energy that can be collected during the breaking action of the swing mechanism, then, since this is the net energy that can be used to recharge an energy storage device without using the engine to help recharge the energy storage device, the system limits the use of the energy storage device to that net amount predicted to be available from the recovery period. The net regenerative energy is calculated by considering motor and inverter efficiencies for transferring energy to the battery and changes in the boom/stick/bucket inertia moment.

Claims

1. A machine having a body, a chassis, and an engine comprising:

a swing mechanism that rotates the body relative to the chassis about an axis;

an electric motor/generator in electrical communication with the swing mechanism;

an energy storage device in electrical communication with the swing mechanism; and

an energy management system configured to determine a transition from a discharge period to a recovery period and responsively;

estimate the net energy generated by the swing mechanism during the recovery period;

limit the energy available for use from the energy storage device during the discharge period to the estimated net energy generated from the swing mechanism; and

recharge the battery from the actual net energy generated during the recovery period.

2. The machine of claim 1, wherein the transition from a discharge period to a recovery period is correlated to the position of the body relative to the chassis.

3. The machine of claim 1 wherein the energy storage device is a battery.

4. The machine of claim 1 wherein the electric motor/generator operates in both a generating mode wherein energy is supplied to a swing motor and a motoring mode wherein engine transient assist is provided.

5. The machine of claim 4 wherein the engine transient assist is provided for between about 1 to about 2 seconds.

6. The machine of claim 1 further including one three-phase power inverter using IGBT technology.

7. The machine of claim 6 wherein the three-phase power inverter is rated from about 450 VAC to about 500 VAC.

8. The machine of claim 1 wherein the energy storage device is maintained as a substantially constant state of charge.

9. The machine of claim 1 further including a DC bus from about 600 VDC to about 700 VDC.

10. The machine of claim 1 wherein the swing mechanism includes a swing motor.

11. The machine of claim 10 wherein the swing motor is able to act as a motor/generator and recover at least about 40% of the swing energy.

12. The machine of claim 10 wherein the swing motor is at least about 85% efficient.

13. The machine of claim 1 wherein the electric motor/generator is at least about 90% efficient.

14. The machine of claim 1 wherein the energy storage device is at least about 85% efficient.