MOTOR SPEED CONTROLLER

• US 20100090637A1
• Filed: 10/09/2008
• Published: 04/15/2010
• Est. Priority Date: 10/09/2008
• Status: Active Grant

• Current Assignee: BSH Home Appliances Corporation (Robert Bosch GmbH)
• Original Assignee: BSH Home Appliances Corporation (Robert Bosch GmbH)
• Inventors: Savitz, George
• Granted Patent: US 8,198,853 B2
• Time in Patent Office: Days
• US Class Current: 318/494
• CPC Class Codes: H02P 23/14 Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage

Abstract

A motor speed controller and a method of controller a speed of a motor are provided. The system and method include a motor and a motor controller that monitors operation of the motor based on electromotive force (EMF) conditions of the motor. The motor controller cuts a voltage to the motor, measures an electromotive force (EMF) of the motor at a predetermined time after the cutting of the voltage to the motor, and compares the measured electromotive force (EMF) to a table.

Claims

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

cutting a voltage to the motor;

measuring an electromotive force (EMF) of the motor at a predetermined time after the cutting of the voltage to the motor; and

comparing the measured electromotive force (EMF) to a table.

2. The method according to claim 1, wherein the motor is an AC inductive motor.

3. The method according to claim 1, wherein the table is a software table or database.

4. The method according to claim 1, wherein the table is specific to the motor being used.

5. The method according to claim 1, wherein the table includes a threshold value.

6. The method according to claim 5,

wherein the threshold value includes a first threshold for a high speed mode, and

wherein the threshold value includes a second threshold for a low speed mode.

7. The method according to claim 5, wherein the threshold value is based on an application of the motor.

8. The method according to claim 1, further comprising:

determining one of;

whether the motor was running at a time of the cutting of the voltage to the motor based on the comparison of the measured electromotive force (EMF) to the table,

a speed of the motor at a time of the cutting of the voltage to the motor based on the comparison of the measured electromotive force (EMF) to the table, and

whether the motor is operating below a predetermined or threshold value at a time of the cutting of the voltage to the motor based on the comparison of the measured electromotive force (EMF) to the table.

9. The method according to claim 8, further comprising:

outputting a first signal indicating that the motor is operating properly if the operation of the motor is determined to be equal to or greater than the predetermined or threshold value, and

outputting a second signal indicating that the motor is operating improperly if the operation of the motor is determined to be less than the predetermined or threshold value.

10. The method according to claim 9,

wherein the first signal is a first Hall effect mimicking signal, and

wherein the second signal is a second Hall effect mimicking signal.

11. The method according to claim 9, further comprising:

turning the voltage to the motor back on based on the outputting of the first signal, and

sending a signal to default the motor to a high speed setting based on the outputting of the second signal.

12. The method according to claim 11, further comprising:

setting a timer upon turning the voltage to the motor back on based on the outputting of the first signal; and

re-cutting the voltage to the motor after the timer has expired.

13. The method according to claim 1, further comprising:

turning the voltage to the motor back on.

14. The method according to claim 13,

wherein the voltage is periodically cut and turned back on, and

wherein the electromotive force (EMF) is measured during periods when the voltage is cut.

15. The method according to claim 1,

wherein a microcontroller performs the comparing of the measured electromotive force (EMF) to the table, and

wherein the method includes normalizing the measured electromotive force (EMF) of the motor to be within an operating range of a microcontroller.

16. The method according to claim 1, further comprising:

powering the motor in a full-on state to provide a high speed mode; and

cutting a leading edge of a power signal to the motor to reduce an amount of on-time of the motor and provide a low speed mode.

17. A method of controlling a motor, the method comprising:

periodically cutting a voltage to the motor;

measuring an electromotive force (EMF) of the motor at a predetermined period of time after the cutting of the voltage to the motor; and

comparing the measured electromotive force (EMF) to a table to determine if the motor is operating properly,

wherein, if the motor is determined to be operating properly, the method includes outputting a first signal and turning the voltage to the motor back on, and

wherein, if the motor is determined to be operating improperly, the method includes outputting a second signal.

18. A sensorless motor speed controller system comprising:

a motor; and

a motor controller that monitors operation of the motor based on electromotive force (EMF) conditions of the motor.

19. The system according to claim 18, wherein the motor is an AC inductive motor.

20. The system according to claim 18,

wherein the motor controller cuts a voltage to the motor, measures an electromotive force (EMF) of the motor during a motor off time, and compares the measured electromotive force (EMF) to a table, and

wherein the motor controller includes:

a speed sensing module that measures the electromotive force (EMF) of the motor;

a microcontroller that receives the measured electromotive force (EMF) from the speed sensing module and compares the measured electromotive force (EMF) to a table.

21. The system according to claim 20, wherein the speed sensing module normalizes the measured electromotive force (EMF) of the motor to be within an operating range of the microcontroller.

22. The system according to claim 18, wherein the motor controller determines one of whether the motor was running based on the electromotive force (EMF) conditions of the motor, a speed of the motor based on the electromotive force (EMF) conditions of the motor, and whether the motor was operating below a predetermined or threshold value based on the electromotive force (EMF) conditions of the motor.

23. The system according to claim 18,

wherein the motor controller outputs a first signal indicating that the motor is operating properly if the electromotive force (EMF) conditions of the motor are equal to or greater than a predetermined or threshold value, and

wherein the motor controller outputs a second signal indicating that the motor is operating improperly if the electromotive force (EMF) conditions of the motor are less than a predetermined or threshold value.

24. A sensorless motor speed controller that monitors operation of a motor based on electromotive force (EMF) conditions of the motor, the sensorless motor speed controller comprising:

a microcontroller that cuts a voltage to the motor; and

a speed sensing module that measures the electromotive force (EMF) of the motor at a time when the voltage is cut,

wherein the microcontroller receives the measured electromotive force (EMF) from the speed sensing module and compares the measured electromotive force (EMF) to a table.

25. The sensorless motor speed controller according to claim 24, wherein the motor is an AC inductive motor.