THERMAL PROTECTION METHOD AND SYSTEM TO MAXIMIZE AVAILABILITY OF ELECTRIC DRIVE SYSTEM

• US 20140191695A1
• Filed: 01/08/2013
• Published: 07/10/2014
• Est. Priority Date: 01/08/2013
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell Incorporated (Honeywell International Inc.)
• Inventors: GANEV, EVGENI, CHIANG, CHIYUAN
• Granted Patent: US 8,933,658 B2
• Time in Patent Office: Days
• US Class Current: 318/472
• CPC Class Codes: H02H 5/04 responsive to abnormal temperature specially adapted for electric machines H02H7/0852
• CPC Class Codes: H02H 7/0852 directly responsive to abnormal temperature by using a temperature sensor in a control circuit H02H7/0833
• CPC Class Codes: H02M 1/327 against abnormal temperatures
• CPC Class Codes: H02P 29/68 based on the temperature of a drive component or a semiconductor component

Abstract

An electric drive system may include a plurality of heat sensitive components, at least one temperature sensor positioned in or on each of the components and a system controller. The temperature sensors may be interconnected with the system controller to transmit temperature data from their respective heat sensitive components to the system controller. The system controller may be configured to transmit a reduced performance command in the event that a reached-temperature-threshold-limit signal is received from any one or more of the temperature sensors. System shutdown due to over temperature faults may be avoided.

Claims

1. An electric drive system comprising:

a plurality of heat sensitive components;

at least one temperature sensor positioned in or on each of the plurality of heat sensitive components;

a system controller,

the temperature sensors interconnected with the system controller to transmit temperature data from their respective heat sensitive components to the system controller, and

the system controller configured to transmit a reduced performance command in the event that a reached-temperature-threshold-limit signal is received from any one or more of the temperature sensors.

2. The electric drive system of claim 1 wherein the system controller is interconnected with a motor controller and the reduced performance command is transmitted to the motor controller through said interconnection.

3. The electric drive system of claim 2 wherein the motor controller is one heat sensitive component of the plurality of heat sensitive components.

4. The electric drive system of claim 2 wherein the reduced performance command comprises a speed reduction command.

5. The electric drive system of claim 4 wherein the motor controller is configured to reduce voltage to a motor of the drive system upon receipt of the reduced speed command.

6. The electric drive system of claim 2 wherein the reduced performance command comprises an acceleration reduction command.

7. The electric drive system of claim 6 wherein the motor controller is configured to reduce current to a motor of the drive system upon receipt of the acceleration reduction command.

8. A system controller for an electric drive system comprising:

a temperature comparator configured to receive inputs from temperature sensors located on or in a plurality of components of the electric drive system; and

a command generator interconnected with the temperature comparator and interconnected with a motor controller of the electric drive system to transmit a reduced performance command to the motor controller responsively to receipt of a reached-temperature-threshold-limit signal being received by the temperature comparator.

9. The system controller of claim 8 further comprising:

a reference unit configured to store functional relationships between rates of change of temperatures of the components of the electric drive system and types, magnitudes or rates of performance reduction of the components; and

an interconnection path between the command generator and the reference unit whereby the command generator is provided with component-specific instructions relating to types, magnitudes or rates of performance reductions commands to produce.

10. The system controller of claim 9 wherein the reference unit is programmed with look-up tables and predetermined mathematic functions.

11. The system controller of claim 8 wherein the command generator is configured to produce performance reduction commands in the form of speed reduction commands.

12. The system controller of claim 8 wherein the command generator is configured to produce performance reduction commands in the form of acceleration reduction commands.

13. The system controller of claim 8:

wherein the command generator is configured to produce performance reduction commands in the form of speed reduction commands and said speed reduction commands are commands for reduction of voltage provided to a motor of the electric drive system by the motor controller; and

wherein the command generator is configured to produce performance reduction commands in the form of acceleration reduction commands and said acceleration reduction commands are commands for reduction of current provided to the motor of the electric drive system by the motor controller.

14. The system controller of claim 8 wherein the comparator further comprises a low win logic circuit configured to determine which one of a plurality of the reached-temperature-threshold-limit signals requires the most performance reduction to achieve mitigation.

15. A method for operating an electric drive system comprising the steps of:

establishing temperature threshold limits for a plurality of components of the electric drive system, the temperature threshold limit for any particular one of the plurality of components being at a temperature lower than temperature shutdown limit for the particular one of the plurality of components;

monitoring temperatures of the plurality of components to detect if the temperature of any particular one of the plurality of components reaches the temperature threshold limit for said particular one of the plurality of components;

initiating a reduction in performance of the electric drive system in the event that the temperature of any particular one of the plurality of components reaches the threshold limit for said particular one of the plurality of components.

16. The method of claim 15 further comprising the step of maintaining the electric drive system in a state of reduced performance until the temperatures of all of the components is below their respective temperature threshold limits.

17. The method of claim 15 wherein the step of initiating a reduction in performance comprises commanding a motor controller of the electric drive system to reduce speed of a motor of the electric drive system.

18. The method of claim 15 wherein the step of initiating a reduction in performance comprises commanding a motor controller of the electric drive system to reduce acceleration of a motor of the electric drive system.

19. The method of claim 15 further comprising the step of determining a functional relationship between performance reduction and rate of temperature decrease for each of the plurality of components of the electric drive system.

20. The method of claim 19 further comprising commanding a motor controller of the electric drive system to reduce speed or acceleration of a motor of the electric drive system in accordance with the functional relationship between performance reduction and rate of temperature decrease.