Systems and methods for operating motors with a single motor position signal

1. A method for operating a motor, the method comprising:

receiving a first output from a motor electric position sensor;

receiving a second output from the motor electric position sensor;

determining that the first output is not faulted;

determining that the second output is faulted;

synthesizing a synthesized second output from the first output and from an estimated motor angular velocity;

calculating a motor angular position from the first output and the synthesized second output;

estimating a motor angular velocity from the motor angular position; and

operating the motor to produce torque based on the motor angular position and the motor angular velocity.

2. The method of claim 1 wherein the first output is a sine envelope signal or a cosine envelope signal.

3. The method of claim 1 wherein a vector-based position sensor coupled to the motor provides the first output.

4. The method of claim 1 wherein the first output is created by a resolver, a magneto-resistive sensor, a Hall effect sensor, or an eddy current sensor.

5. The method of claim 1 wherein a quadrature envelope generator synthesizes the synthesized second output from the first output and the estimated motor angular velocity.

6. The method of claim 5 wherein the quadrature envelope generator is a frequency-adapted all-pass filter or a spatial derivative filter.

7. The method of claim 1 wherein the method operates the motor to produce torque based on the motor angular position and the estimated motor angular velocity when an absolute motor speed is greater than or equal to a selected absolute value |n1|, and wherein the method further comprises:

identifying that the absolute motor speed is less than the selected absolute value |n1|; and

after identifying that the absolute motor speed is less than the selected absolute value |n1|, controlling the motor to generate no torque and no current.

8. The method of claim 7 further comprising:

after initially controlling the motor to generate no torque and no current, determining that the absolute motor speed is greater than or equal to a selected value |n2|, generating torque with the motor, and detecting a direction of rotation of the motor.

9. The method of claim 8 wherein determining that the absolute motor speed is greater than or equal to a selected value |n2| comprises performing a two pulse-per-revolution emulated encoder process or performing a speed ceiling calculation.

10. The method of claim 7 further comprising:

after initially controlling the motor to generate no torque and no current, determining that the absolute motor speed is greater than or equal to a selected value |n2|, generating torque with the motor and detecting a direction of rotation of the motor, and, after a time interval t1 from determining that the absolute motor speed is greater than or equal to a selected value |n2|, operating the motor to produce torque based on the motor angular position and the motor angular velocity.

11. The method of claim 8 wherein detecting the direction of rotation of the motor comprises performing a three-phase short current-based detection process or performing a current regulator-based detection process.

12. The method of claim 8 further comprising:

determining that the absolute motor speed is greater than or equal to a selected value n3, wherein the absolute value of |n3| is greater than or equal to the absolute value of |n2|; and

after identifying that the absolute motor speed is greater than or equal to a selected value n3, operating the motor to produce torque based on the motor angular position and the motor angular velocity.

13. A method for operating a motor, the method comprising:

receiving a first output from a motor electric position sensor;

synthesizing a synthesized second output from the first output and from an estimated motor angular velocity, wherein a quadrature envelope generator synthesizes the synthesized second output from the first output and the estimated motor angular velocity, and wherein the quadrature envelope generator is a frequency-adapted all-pass filter or a spatial derivative filter;

calculating a motor angular position from the first output and the synthesized second output;

estimating a motor angular velocity from the motor angular position; and

operating the motor to produce torque based on the motor angular position and the motor angular velocity.

14. The method of claim 13 wherein the first output is a sine envelope signal or a cosine envelope signal.

15. The method of claim 13 wherein the method operates the motor to produce torque based on the motor angular position and the estimated motor angular velocity when an absolute motor speed is greater than or equal to a selected absolute value |n1|, and wherein the method further comprises:

identifying that the absolute motor speed is less than the selected absolute value |n1|; and

after identifying that the absolute motor speed is less than the selected absolute value |n1|, controlling the motor to generate no torque and no current.

16. The method of claim 15 further comprising:

after initially controlling the motor to generate no torque and no current, determining that the absolute motor speed is greater than or equal to a selected value |n2|, generating torque with the motor, and detecting a direction of rotation of the motor;

determining that the absolute motor speed is greater than or equal to a selected value n3, wherein the absolute value of |n3| is greater than or equal to the absolute value of |n2|; and

after identifying that the absolute motor speed is greater than or equal to a selected value n3, operating the motor to produce torque based on the motor angular position and the motor angular velocity.

17. The method of claim 15 further comprising:

after initially controlling the motor to generate no torque and no current, determining that the absolute motor speed is greater than or equal to a selected value |n2|, generating torque with the motor and detecting a direction of rotation of the motor, and, after a time interval t1 from determining that the absolute motor speed is greater than or equal to a selected value |n2|, operating the motor to produce torque based on the motor angular position and the motor angular velocity.

18. A method for operating a motor, the method comprising:

receiving a first output from a motor electric position sensor;

synthesizing a synthesized second output from the first output and from an estimated motor angular velocity;

calculating a motor angular position from the first output and the synthesized second output;

estimating a motor angular velocity from the motor angular position;

operating the motor to produce torque based on the motor angular position and the motor angular velocity when an absolute motor speed is greater than or equal to a selected absolute value |n1|;

identifying that the absolute motor speed is less than the selected absolute value |n1|; and

after identifying that the absolute motor speed is less than the selected absolute value |n1|, controlling the motor to generate no torque and no current.

19. The method of claim 18 further comprising:

after initially controlling the motor to generate no torque and no current, determining that the absolute motor speed is greater than or equal to a selected value |n2|, generating torque with the motor, and detecting a direction of rotation of the motor.

20. The method of claim 19 wherein determining that the absolute motor speed is greater than or equal to a selected value |n2| comprises performing a two pulse-per-revolution emulated encoder process or performing a speed ceiling calculation.

21. The method of claim 19 wherein detecting the direction of rotation of the motor comprises performing a three-phase short current-based detection process or performing a current regulator-based detection process.

22. The method of claim 19 further comprising:

determining that the absolute motor speed is greater than or equal to a selected value n3, wherein the absolute value of |n3| is greater than or equal to the absolute value of |n2|; and

after identifying that the absolute motor speed is greater than or equal to a selected value |n3|, operating the motor to produce torque based on the motor angular position and the motor angular velocity.