Determination method and apparatus for BLDC counter-electromotive force zero crossing point threshold, and storage medium

1. A method for determining Back Electromotive Force (BEMF) zero-crossing thresholds of a Brushless Direct Current (BLDC) motor, comprising:

detecting a time interval between BEMF zero-crossing points of two adjacent sectors of the BLDC motor to obtain at least two first time intervals;

determining errors of the BEMF zero-crossing points by using the obtained at least two first time intervals;

converging the determined errors of the BEMF zero-crossing points to obtain correction increments of the BEMF zero-crossing thresholds;

determining the BEMF zero-crossing thresholds by using the obtained correction increments of the BEMF zero-crossing thresholds;

comparing a terminal voltage with the determined BEMF zero-crossing thresholds to obtain comparison results; and

determining whether respective BEMFs cross zero based on the comparison results.

2. The method of claim 1 , wherein determining the errors of the BEMF zero-crossing points by using the obtained at least two first time intervals comprises:

determining a first error of each phase of the BLDC motor by using the obtained at least two first time intervals in combination with a relationship between a half-period angle of a first BEMF signal and a corresponding half-period angle of a second BEMF signal, to obtain a first set of errors, wherein the first BEMF signal is an ideal BEMF signal, and the second BEMF signal is an actual BEMF signal; and

converging errors in the first set of errors to obtain the correction increments of the BEMF zero-crossing thresholds.

3. The method of claim 1 , wherein determining the errors of the BEMF zero-crossing points by using the obtained at least two first time intervals comprises:

determining a second error of each phase of the BLDC motor by using the obtained at least two first time intervals in combination with a relationship between a zero point angle interval of two adjacent sectors of a first BEMF signal and a zero point angle interval of two corresponding adjacent sectors of a second BEMF signal, to obtain a second set of errors, wherein the first BEMF signal is an ideal BEMF signal, and the second BEMF signal is an actual BEMF signal; and

converging errors in the second set of errors to obtain the correction increments of the BEMF zero-crossing thresholds.

4. The method of claim 1 , wherein determining the errors of the BEMF zero-crossing points by using the obtained at least two first time intervals comprises:

determining a first error of each phase of the BLDC motor by using the obtained at least two first time intervals in combination with a relationship between a half-period angle of a first BEMF signal and a corresponding half-period angle of a second BEMF signal, to obtain a first set of errors; and determining a second error of each phase of the BLDC motor by using the obtained at least two first time intervals in combination with a relationship between a zero point angle interval of two adjacent sectors of the first BEMF signal and a zero point angle interval of two corresponding adjacent sectors of the second BEMF signal, to obtain a second set of errors, wherein the first BEMF signal is an ideal BEMF signal, and the second BEMF signal is an actual BEMF signal;

converging errors in the first set of errors to obtain first correction increments of the BEMF zero-crossing thresholds, and converging errors in the second set of errors to obtain second correction increments of the BEMF zero-crossing thresholds; and

determining the BEMF zero-crossing thresholds by using the first correction increments of the BEMF zero-crossing thresholds and the second correction increments of the BEMF zero-crossing thresholds.

5. The method of claim 2 , wherein determining the first error of each phase of the BLDC motor by using the obtained at least two first time intervals in combination with the relationship between the half-period angle of the first BEMF signal and the corresponding half-period angle of the second BEMF signal comprises:

determining, using the obtained at least two first time intervals, time intervals of BEMF zero-crossing points of sectors corresponding to a half period of a mechanical period of a body of the BLDC motor, to obtain at least two second time intervals; and

determining the first error of each phase of the BLDC motor by using the obtained at least two second time intervals in combination with the relationship between the half-period angle of the first BEMF signal and the corresponding half-period angle of the second BEMF signal.

6. The method of claim 1 , wherein converging the determined error signals of the BEMF zero-crossing points to obtain the correction increments of the BEMF zero-crossing thresholds comprises:

converging the determined error signals of the BEMF zero-crossing points with a Proportional Integral (PI) controller to obtain the correction increments of the BEMF zero-crossing thresholds.

7. A device for determining Back Electromotive Force (BEMF) zero-crossing thresholds of a Brushless Direct Current (BLDC) motor, the device comprising:

a detecting device configured to detect a time interval between BEMF zero-crossing points of two adjacent sectors of the BLDC motor to obtain at least two first time intervals;

a first determining device configured to determine errors of the BEMF zero-crossing points by using the obtained at least two first time intervals;

a second determining device configured to converge the determined errors of the BEMF zero-crossing points to obtain correction increments of the BEMF zero-crossing thresholds; and

a third determining device;

wherein the third determining device is configured to determine the BEMF zero-crossing thresholds by using the correction increments of the BEMF zero-crossing thresholds, compare a terminal voltage with the determined BEMF zero-crossing thresholds to obtain comparison results, and determine whether respective BEMFs cross zero based on the comparison results.

8. The device of claim 7 , wherein:

the first determining device is configured to determine a first error of each phase of the BLDC motor by using the obtained at least two first time intervals in combination with a relationship between a half-period angle of a first BEMF signal and a corresponding half-period angle of a second BEMF signal, to obtain a first set of errors, wherein the first BEMF signal is an ideal BEMF signal, and the second BEMF signal is an actual BEMF signal; and

the second determining device is configured to converge errors in the first set of errors to obtain the correction increments of the BEMF zero-crossing thresholds.

9. The device of claim 7 , wherein:

the first determining device is configured to determine a second error of each phase of the BLDC motor by using the obtained at least two first time intervals in combination with a relationship between a zero point angle interval of two adjacent sectors of a first BEMF signal and a zero point angle interval of two corresponding adjacent sectors of a second BEMF signal, to obtain a second set of errors, wherein the first BEMF signal is an ideal BEMF signal, and the second BEMF signal is an actual BEMF signal; and

the second determining device is configured to converge errors in the second set of errors to obtain the correction increments of the BEMF zero-crossing thresholds.

10. The device of claim 7 , wherein:

the first determining device is configured to: determine a first error of each phase of the BLDC motor by using the obtained at least two first time intervals in combination with a relationship between a half-period angle of a first BEMF signal and a corresponding half-period angle of a second BEMF signal, to obtain a first set of errors; and determine a second error of each phase of the BLDC motor by using the obtained at least two first time intervals in combination with a relationship between a zero point angle interval of two adjacent sectors of the first BEMF signal and a zero point angle interval of two corresponding adjacent sectors of the second BEMF signal, to obtain a second set of errors, wherein the first BEMF signal is an ideal BEMF signal, and the second BEMF signal is an actual BEMF signal;

the second determining device is configured to converge errors in the first set of errors to obtain first correction increments of the BEMF zero-crossing thresholds; and converge errors in the second set of errors to obtain second correction increments of the BEMF zero-crossing thresholds; and

the third determining device is configured to determine the BEMF zero-crossing thresholds by using the first correction increments of the BEMF zero-crossing thresholds and the second correction increments of the BEMF zero-crossing thresholds.

11. A device for determining Back Electromotive Force (BEMF) zero-crossing thresholds of a Brushless Direct Current (BLDC) motor, comprising:

a processor and a memory configured to store computer programs executable on the processor, when executed by the processor, cause the processor to:

detect a time interval between BEMF zero-crossing points of two adjacent sectors of the BLDC motor to obtain at least two first time intervals;

determine errors of the BEMF zero-crossing points by using the obtained at least two first time intervals;

converge the determined errors of the BEMF zero-crossing points to obtain correction increments of the BEMF zero-crossing thresholds; and

determine the BEMF zero-crossing thresholds by using the obtained correction increments of the BEMF zero-crossing thresholds;

compare a terminal voltage with the determined BEMF zero-crossing thresholds to obtain comparison results; and

determine whether respective BEMFs cross zero based on the comparison results.

12. A storage medium having stored thereon computer programs that, when executed by a processor, when executed by the processor, cause the processor to:

detect a time interval between BEMF zero-crossing points of two adjacent sectors of the BLDC motor to obtain at least two first time intervals;

determine errors of the BEMF zero-crossing points by using the obtained at least two first time intervals;

converge the determined errors of the BEMF zero-crossing points to obtain correction increments of the BEMF zero-crossing thresholds; and

determine the BEMF zero-crossing thresholds by using the obtained correction increments of the BEMF zero-crossing thresholds;

compare a terminal voltage with the determined BEMF zero-crossing thresholds to obtain comparison results; and

determine whether respective BEMFs cross zero based on the comparison results.