DC motor control

• US 7,692,399 B2
• Filed: 04/01/2003
• Issued: 04/06/2010
• Est. Priority Date: 04/01/2003
• Status: Active Grant

• Current Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Original Assignee: Hewlett-Packard Development Company, L.P. (HP Inc.)
• Inventors: Davis, Robert D., Harriman, Douglas L., Ewe, Michael Teong Seng
• Primary Examiner(s): Benson; Walter
• Assistant Examiner(s): COLON SANTANA, EDUARDO
• Application Number:
  US10/405,774
• Publication Number:
  US 20040195989A1
• Time in Patent Office: 2,562 Days
• Field of Search: 318/244, 318/245, 318431-474, 318/782, 318/783, 318/789, 388800-824, 361 23- 34, 400144-1451
• US Class Current: 318/798
• CPC Class Codes: H02H 6/00 Emergency protective circuit arrangements responsive to undesired changes from normal non-electric working conditions using simulators of the apparatus being protected, e.g. using thermal images
• CPC Class Codes: H02P 7/28 using semiconductor devices

Abstract

A method of controlling a DC motor is presented. In a determining action, a thermal power dissipation is determined from a motor input and a motor velocity. In another determining action, a motor temperature is determined based on a thermal model using the thermal power dissipation. In an adjusting action, a usage of the motor is adjusted, taking the motor temperature into account.

Claims

1. A method of controlling a DC motor, comprising:

determining a thermal power dissipation from a motor input and a motor velocity, wherein the motor input comprises an applied voltage;

determining a motor temperature based on a thermal model using the thermal power dissipation; and

adjusting a usage of the motor, taking the motor temperature into account, wherein determining the thermal power dissipation from the motor input and the motor velocity comprises;

determining the applied voltage to the DC motor based on the motor input;

determining a voltage generated by the DC motor based on a motor back-EMF constant and the motor velocity; and

determining the thermal power dissipation based on the applied voltage, the voltage generated by the DC motor, a known motor winding resistance, and a known motor driver circuit resistance.

2. The method of claim 1, wherein the thermal power dissipation comprises an instantaneous thermal power dissipation.

3. The method of claim 2, wherein the motor input comprises a pulse-width modulation (PWM) value.

4. The method of claim 1, wherein the thermal power dissipation comprises an average thermal power dissipation.

5. The method of claim 4, wherein the motor input comprises a series of applied voltages.

6. The method of claim 4, wherein the motor input comprises a series of PWM values.

7. The method of claim 1, wherein the known motor winding resistance is adjusted to compensate for temperature sensitivity.

8. An imaging device, comprising:

at least one print cartridge;

a DC motor coupled to the at least one print cartridge; and

a controller, coupled to the DC motor, configured to control the DC motor using the method of claim 1.

9. A method of controlling a DC motor, comprising:

determining a thermal power dissipation from a motor input and a motor velocity;

determining a motor temperature based on a thermal model using the thermal power dissipation; and

adjusting a usage of the motor, taking the motor temperature into account;

wherein determining the motor temperature based on the thermal model using the thermal power dissipation comprises;

determining a change in a motor winding temperature based on a stored motor winding temperature, a stored motor case temperature, and the thermal power dissipation; and

determining a change in a motor case temperature based on the stored motor case temperature, the stored motor winding temperature, and an ambient temperature.

10. The method of claim 9, wherein the ambient temperature is an assumed ambient temperature.

11. The method of claim 9, wherein the ambient temperature is determined by a thermal sense resistor on a print cartridge.

12. A method of controlling a DC motor in an imaging device having a print cartridge coupled to the DC motor, comprising:

while the print cartridge is in an uncapped state;

storing at least one motor input value and at least one motor speed;

determining a thermal power dissipation from the at least one stored motor input value and the at least one motor speed;

determining a motor temperature based on the thermal power

dissipation, wherein determining the motor temperature based on thermal power dissipation comprises;

determining a change in a motor winding temperature based on a stored motor winding temperature, a stored motor case temperature, and the thermal power dissipation; and

determining a change in a motor case temperature based on the stored motor case temperature, the stored motor winding temperature, and an ambient temperature; and

adjusting a usage of the DC motor, taking the motor temperature into account.

13. The method of claim 12, further comprising:

while the print cartridge is in a capped state;

storing the motor temperature.

14. The method of claim 13, wherein the at least one motor input comprises a PWM value.

15. The method of claim 13, wherein the thermal power dissipation comprises an instantaneous thermal power dissipation.

16. The method of claim 13, wherein the thermal power dissipation comprises an average thermal power dissipation.

17. The method of claim 13, wherein determining a motor temperature based on the thermal power dissipation further comprises determining the motor temperature based on a thermal model using the thermal power dissipation.

18. A method, comprising:

determining a speed of a DC motor;

determining an input to the DC motor, wherein the input comprises a series of applied voltages and a known motor winding resistance that has been adjusted based on a previously determined temperature of the DC motor;

calculating a thermal power dissipation using the determined speed and the determined input;

calculating a temperature of the DC motor using the calculated thermal power dissipation;

adjusting usage of the DC motor based on the calculated temperature.