CN112468028A - Low-speed detection method and device of brushless motor - Google Patents
Low-speed detection method and device of brushless motor Download PDFInfo
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- CN112468028A CN112468028A CN202011289033.4A CN202011289033A CN112468028A CN 112468028 A CN112468028 A CN 112468028A CN 202011289033 A CN202011289033 A CN 202011289033A CN 112468028 A CN112468028 A CN 112468028A
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P6/00—Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
- H02P6/14—Electronic commutators
- H02P6/16—Circuit arrangements for detecting position
- H02P6/17—Circuit arrangements for detecting position and for generating speed information
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- H—ELECTRICITY
- H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
- H02P—CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
- H02P23/00—Arrangements or methods for the control of AC motors characterised by a control method other than vector control
- H02P23/14—Estimation or adaptation of motor parameters, e.g. rotor time constant, flux, speed, current or voltage
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Abstract
The embodiment of the invention discloses a low-speed detection method and a low-speed detection device of a brushless motor, wherein the detection method comprises the following steps: acquiring pulse signals generated by a Hall element, and recording the interval between two adjacent pulse signals; and calculating the rotating speed of the rotor of the brushless motor according to the interval of two adjacent pulse signals. According to the embodiment of the invention, the rotating speed detection of the brushless motor at low rotating speed is realized by acquiring the interval of two adjacent pulse signals and calculating the average rotating speed of the rotor of the brushless motor in the interval time according to the interval of the two adjacent pulse signals.
Description
Technical Field
The embodiment of the invention relates to the technical field of brushless motors, in particular to a low-speed detection method and device of a brushless motor.
Background
The brushless motor is composed of a motor main body and a driver, and is a typical electromechanical integration product.
Fig. 1 is a schematic structural view of a brushless motor provided in the prior art, and referring to fig. 1, a rotor 1 of the brushless motor is adhered with a magnetized permanent magnet and is connected with an output shaft together with a housing, and a stator has winding coils 2, and the winding coils 2 are wound on a core 3. Generally, in a brushless motor on the market, at least two hall elements 4 are arranged on a rotor output shaft portion to perform speed detection in a high-speed state, which can meet the detection of a high rotation speed, but when the rotation speed is low, the resolution of the hall elements 4 is low, which cannot meet the detection of a low rotation speed.
Disclosure of Invention
The embodiment of the invention provides a low-speed detection method and device of a brushless motor, which are used for realizing the rotation speed detection of the brushless motor at low rotation speed.
In a first aspect, an embodiment of the present invention provides a low-speed detection method for a brushless motor, including:
acquiring pulse signals generated by a Hall element, and recording the interval between two adjacent pulse signals;
and calculating the rotating speed of the rotor of the brushless motor according to the interval of two adjacent pulse signals.
Optionally, the hall element detects a magnetic substance in the rotor of the brushless motor, and generates a high level signal when detecting the magnetic substance, and generates a low level signal when not detecting the magnetic substance.
Optionally, the hall element is connected with the processing unit; the processing unit is a single chip microcomputer, the processing unit is provided with a timer port and a timer, and the Hall element is connected with the timer port; the acquiring the pulse signals generated by the hall element and recording the interval between two adjacent pulse signals includes:
the timer captures and reads the pulse signal generated by the Hall sensor; recording the time of level jump of two adjacent pulse signals;
and acquiring the interval according to the time of level jump of two adjacent pulse signals.
Optionally, the calculating the rotation speed of the rotor of the brushless motor according to the interval between two adjacent pulse signals includes:
the processing unit calculates the rotating speed of the rotor of the brushless motor according to the interval of the corresponding moments when two adjacent high levels jump to low levels;
or the processing unit calculates the rotating speed of the rotor of the brushless motor according to the interval of the corresponding time when two adjacent moments jump from the low level to the high level.
Optionally, the processing unit calculates the rotation speed of the rotor of the brushless motor according to an interval between two adjacent times corresponding to the time when the high level jumps to the low level, and determines the rotation speed based on the following:
P/(T2-T1), where v is the rotation speed of the brushless motor rotor; p is a correction coefficient which is obtained based on the product of the rotating speed of the rotor obtained by an external speed measuring tool and the high-low level jump time difference corresponding to the measured rotating speed; t1 is the time point of transition from high level to low level, and T2 is the time point of transition from high level to low level;
the processing unit calculates the rotating speed of the rotor of the brushless motor according to the interval of the corresponding time of two adjacent jumps from the low level to the high level, and the rotating speed is determined based on the following steps:
P/(T5-T4), where v is the rotation speed of the brushless motor rotor; p is the correction coefficient; t4 is the time point of transition from low level to high level, and T5 is the time point of transition from low level to high level.
Optionally, the number of the hall elements is at least two, and the hall elements are arranged at the output shaft part of the brushless motor rotor at intervals, and the detection method further includes:
the processing unit determines the rotating speed direction of the brushless motor rotor according to the phase difference of the pulse signals generated by at least two Hall elements.
In a second aspect, an embodiment of the present invention provides a speed detection apparatus for a brushless motor, including a hall element and a processing unit; the processing unit includes:
the interval acquisition module is used for acquiring pulse signals generated by the Hall element and recording the interval between two adjacent pulse signals;
and the rotating speed calculating module is used for calculating the rotating speed of the rotor of the brushless motor according to the interval of two adjacent pulse signals.
Optionally, the hall element is configured to generate a high level signal when the magnetic substance is detected, and generate a low level signal when the magnetic substance is not detected.
Optionally, the hall element is connected to the processing unit, the processing unit further includes a timer and a timer port, and the hall element is connected to the timer port;
the timer is used for capturing and reading pulse signals generated by the Hall sensor and recording the high-low level jumping time of two adjacent pulse signals;
the interval acquisition module is further configured to acquire the interval according to a time of level jump of two adjacent pulse signals.
Optionally, the number of the hall elements is at least two, the hall elements are arranged at the output shaft part of the brushless motor rotor at intervals, and the processing unit is further configured to determine the rotation speed direction of the brushless motor rotor according to the phase difference of the pulse signals generated by the at least two hall elements.
The embodiment of the invention provides a low-speed detection method and a low-speed detection device of a brushless motor, wherein the detection method comprises the following steps: acquiring pulse signals generated by a Hall element, and recording the interval between two adjacent pulse signals; and calculating the rotating speed of the rotor of the brushless motor according to the interval of two adjacent pulse signals. According to the embodiment of the invention, the interval of two adjacent pulse signals is obtained, the average rotating speed of the rotor of the brushless motor in the interval time is calculated according to the interval of the two adjacent pulse signals, the rotating speed of the rotor is obtained by calculating the number of the pulse signals generated by the Hall element in the prior art, and the rotating speed of the rotor is obtained by calculating the interval between the adjacent pulse signals generated by the Hall element, so that the problem that the resolution ratio of a Hall sensor is low when the rotating speed is low, the detection of low rotating speed cannot be met is solved, and the rotating speed detection of the brushless motor at the low rotating speed is realized.
Drawings
Fig. 1 is a schematic structural view of a brushless motor provided in the prior art;
fig. 2 is a flowchart of a low-speed detection method for a brushless motor according to an embodiment of the present invention;
fig. 3 is a flowchart of a low-speed detection method for a brushless motor according to a second embodiment of the present invention;
fig. 4 is a waveform diagram of a pulse signal at the time of acquiring a transition from a high level to a low level according to a second embodiment of the present invention;
fig. 5 is a waveform diagram of a pulse signal at the time of acquiring a transition from a low level to a high level according to a second embodiment of the present invention;
fig. 6 is a block diagram of a low-speed detection apparatus of a brushless motor according to a third embodiment of the present invention;
fig. 7 is a block diagram of a low-speed detection apparatus of another brushless motor according to a third embodiment of the present invention;
fig. 8 is a block diagram of another low-speed detection apparatus for a brushless motor according to a third embodiment of the present invention.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings and examples. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures.
Example one
The embodiment of the invention provides a low-speed detection method of a brushless motor, which can be executed by a low-speed detection device of the brushless motor, and the low-speed detection device of the brushless motor can be integrated in the brushless motor. Illustratively, the low speed detection device includes a hall element, which is a rotational speed sensor, for detecting a rotational speed of the brushless motor and generating a pulse signal, and a processing unit for performing the step of calculating the rotational speed.
Fig. 2 is a flowchart of a low-speed detection method for a brushless motor according to an embodiment of the present invention, and referring to fig. 2, the low-speed detection method for a brushless motor includes the following steps:
and S110, acquiring pulse signals generated by the Hall element, and recording the interval between two adjacent pulse signals.
Specifically, the hall element is a magnetic sensor based on the hall effect, and can detect a magnetic field and a change in the magnetic field. Optionally, the hall element is connected to the processing unit, and the hall element detects a magnetic substance in the rotor of the brushless motor, generates a high level signal when detecting the magnetic substance, and generates a low level signal when not detecting the magnetic substance. Namely, the Hall element can generate a pulse signal with alternating high and low levels in the rotation process of the rotor of the brushless motor. For example, the operating voltage of the hall sensor is 5V, and when the magnetic substance is detected, a high-level signal is generated, that is, a voltage of 5V is output; the non-detection of the magnetic substance generates a low level signal, i.e., a 0V voltage is output.
The processing unit is connected with the Hall element to acquire the pulse signals generated by the Hall element and record the interval between two adjacent pulse signals. The interval of the pulse signal is referred to as a time interval.
And S120, calculating the rotating speed of the rotor of the brushless motor according to the interval of the two adjacent pulse signals.
Specifically, the average rotating speed of the brushless motor rotor in the interval time is calculated according to the interval of two adjacent pulse signals by acquiring the interval of the two adjacent pulse signals. In the prior art, a Hall sensor is arranged on the output shaft part of a rotor for detecting the speed in a high-speed state. For example, 3000RPM needs to be detected, 3000 pulse signals can be detected by the hall sensor within 1min, that is, 3000/60 is detected within 1s to be 50 pulse signals, which can meet the detection of high rotation speed; correspondingly, if the rotation speed of 30RPM is detected, the hall sensor can detect 30 pulse signals within 1min, that is, only 30/30-1 pulse signal can be detected within 2s, and in the microelectronic neighborhood, the frequency of the signal is very low, so that the detection of low rotation speed cannot be satisfied. The rotating speed of the rotor is obtained by calculating the number of the pulse signals generated by the Hall element in the prior art, and the rotating speed of the rotor is obtained by calculating the interval between the adjacent pulse signals generated by the Hall element, so that the problem that the resolution of the Hall sensor is low and the detection of low rotating speed cannot be met when the rotating speed is low is solved, and the rotating speed detection of the brushless motor at the low rotating speed is realized.
The embodiment of the invention provides a low-speed detection method of a brushless motor, which comprises the following steps: acquiring pulse signals generated by a Hall element, and recording the interval between two adjacent pulse signals; and calculating the rotating speed of the rotor of the brushless motor according to the interval of two adjacent pulse signals. According to the embodiment of the invention, the interval of two adjacent pulse signals is obtained, the average rotating speed of the rotor of the brushless motor in the interval time is calculated according to the interval of the two adjacent pulse signals, the rotating speed of the rotor is obtained by calculating the number of the pulse signals generated by the Hall element in the prior art, and the rotating speed of the rotor is obtained by calculating the interval between the adjacent pulse signals generated by the Hall element, so that the problem that the resolution ratio of a Hall sensor is low when the rotating speed is low, the detection of low rotating speed cannot be met is solved, and the rotating speed detection of the brushless motor at the low rotating speed is realized.
Example two
The embodiment of the invention provides a low-speed detection method of a brushless motor, which is supplemented and refined on the basis of the first embodiment. The processing unit is a single chip microcomputer and is provided with a timer port and a timer, and the Hall element is connected with the timer port.
Fig. 3 is a flowchart of a low-speed detection method of a brushless motor according to a second embodiment of the present invention, and referring to fig. 3, the method includes:
and S210, capturing and reading the pulse signal generated by the Hall sensor by the timer.
Specifically, the processing unit is a single chip microcomputer and is provided with a timer port and a timer, and the Hall element is connected with the timer port. The processing unit can use STM32 series of singlechip, and the encoder mode can be set to this series of singlechip's timer, can directly use this mode to accurate capture the pulse signal that the hall passes the component and generate.
And S220, recording the time of level jump of two adjacent pulse signals.
Specifically, the pulse signal is obtained by the timer, that is, the waveform of the high and low levels output by the hall element is obtained by the single chip microcomputer, and the timer can record the time corresponding to the waveform while obtaining the waveform, so that the time of high and low level jump of two adjacent pulse signals can be recorded by the timer.
And S230, acquiring an interval according to the level jump time of two adjacent pulse signals.
Specifically, after the timer records the time of level jump of two adjacent pulse signals, the calculation module on the processing unit may calculate the acquisition interval according to the time of level jump of two adjacent pulse signals. Therefore, the single chip microcomputer captures and reads the waveform of the pulse signal generated by the Hall element when the brushless motor rotor rotates through the function of the timer, and after the time of adjacent level jump is recorded, the single chip microcomputer calculates and obtains an interval, namely the time difference of adjacent high and low level jump according to the time of the level jump of two adjacent pulse signals through the calculation function.
And S240, calculating the rotating speed of the rotor of the brushless motor according to the interval of the two adjacent pulse signals.
Optionally, fig. 4 is a waveform diagram of a pulse signal at a time when the pulse signal jumps from the high level to the low level according to the second embodiment of the present invention; fig. 5 is a waveform diagram of a pulse signal at the time of acquiring a transition from a low level to a high level according to a second embodiment of the present invention, and referring to fig. 4 to 5, the transition from the high level to the low level or the transition from the low level to the high level is performed; calculating the rotating speed of the rotor of the brushless motor according to the interval of two adjacent pulse signals, comprising:
the processing unit calculates the rotating speed of the rotor of the brushless motor according to the interval of the corresponding moments when the two adjacent high levels jump to the low levels;
or the processing unit calculates the rotating speed of the rotor of the brushless motor according to the interval of the corresponding time when two adjacent moments jump from the low level to the high level.
Specifically, the high-low level transition of the pulse signal includes a transition from a high level to a low level, or a transition from a low level to a high level. The interval between two adjacent pulse signals may be a time difference between two adjacent time instants at which the pulse signal jumps from high level to low level (see fig. 4), or may be a time difference between two adjacent time instants at which the pulse signal jumps from low level to high level (see fig. 5). Calculating the rotating speed of the rotor of the brushless motor according to the interval of two adjacent pulse signals, wherein the rotating speed of the rotor of the brushless motor is calculated by a processing unit according to the interval of two adjacent moments corresponding to the jump from the high level to the low level; or the processing unit calculates the rotating speed of the rotor of the brushless motor according to the interval of the corresponding time when two adjacent moments jump from the low level to the high level. The faster the speed, the smaller the time difference. The slower the speed, the larger the time difference. If the time difference between the two adjacent pulse signals is larger and larger, it indicates that the rotation speed of the brushless motor rotor performs the deceleration motion (fig. 4-5 all show that the rotation speed of the brushless motor rotor performs the deceleration motion). If the time difference between the two adjacent pulse signals is smaller and smaller, the rotating speed of the rotor of the brushless motor is accelerated. If the obtained time difference of the two adjacent pulse signals is equal, the rotating speed of the rotor of the brushless motor does uniform rotating speed motion.
Optionally, the processing unit calculates the rotation speed of the rotor of the brushless motor according to an interval between two adjacent times corresponding to the time when the high level jumps to the low level, and determines the rotation speed based on the following:
P/(T2-T1), where v is the rotation speed of the brushless motor rotor; p is a correction coefficient, and the correction coefficient is obtained based on the product of the rotating speed of the rotor obtained by an external speed measuring tool and the high-low level jump time difference corresponding to the measured rotating speed; t1 is the time point of transition from high level to low level, and T2 is the time point of transition from high level to low level;
specifically, T2-T1 obtain the time difference, and the faster the speed, the smaller the time difference, which is a negative correlation. The correction factor is required to be divided by the time difference to obtain a positive correlation value, which is the average speed of the time period from T1 to T2. The correction coefficient is different according to different application environments, and the specific value is determined according to actual measurement. The correction coefficient is a constant and can be obtained based on the product of the rotation speed of the rotor obtained by an external speed measuring tool and the high-low level jump time difference corresponding to the measured rotation speed. The correction coefficient P can be used for a long time after being calibrated. The processing unit can calculate the rotating speed of the rotor of the brushless motor according to the interval of the corresponding time when the two adjacent high levels jump to the low levels.
The processing unit calculates the rotating speed of the rotor of the brushless motor according to the interval of the corresponding time of two adjacent jumps from the low level to the high level, and the rotating speed is determined based on the following steps:
P/(T5-T4), where v is the rotation speed of the brushless motor rotor; p is a correction coefficient; t4 is the time point of transition from low level to high level, and T5 is the time point of transition from low level to high level.
Specifically, the same rotation speed of the rotor of the brushless motor is obtained by the processing unit according to the interval between two adjacent times corresponding to the jump from the high level to the low level, and only the interval between the times corresponding to the jump from the high level to the low level is changed to the interval between the times corresponding to the jump from the low level to the high level, which is not described herein again.
Optionally, the number of the hall elements is at least two, and the hall elements are arranged at the output shaft part of the brushless motor rotor at intervals, and the detection method further includes:
the processing unit determines the rotating speed direction of the rotor of the brushless motor according to the phase difference of the pulse signals generated by the at least two Hall elements.
Specifically, at least two hall elements are arranged at intervals on the output shaft part of the brushless motor rotor, and the processing unit can determine that the rotating speed direction of the brushless motor rotor rotates clockwise or anticlockwise according to the phase difference of pulse signals generated by the at least two hall elements.
The embodiment of the invention provides a low-speed detection method of a brushless motor. The detection method comprises the following steps: the timer captures and reads a pulse signal generated by the Hall sensor; recording the time of level jump of two adjacent pulse signals; acquiring an interval according to the time of level jump of two adjacent pulse signals; and calculating the rotating speed of the rotor of the brushless motor according to the interval of two adjacent pulse signals. Wherein, the level jump changes from high level to low level, or from low level to high level; the processing unit calculates the rotating speed of the rotor of the brushless motor according to the interval of the corresponding moments when the two adjacent high levels jump to the low levels; or calculating the rotating speed of the rotor of the brushless motor according to the interval of the corresponding time when two adjacent low levels jump to high levels. The rotating speed of the rotor is obtained by calculating the number of the pulse signals generated by the Hall element in the prior art, and the rotating speed of the rotor is obtained by calculating the interval between the adjacent pulse signals generated by the Hall element, so that the problem that the resolution of the Hall sensor is low and the detection of low rotating speed cannot be met when the rotating speed is low is solved, and the rotating speed detection of the brushless motor at the low rotating speed is realized.
EXAMPLE III
Embodiments of the present invention provide a speed detection apparatus for a brushless motor, which can be used to perform the low-speed detection method provided in any embodiment of the present invention. Fig. 6 is a block diagram of a low-speed detection apparatus of a brushless motor according to a third embodiment of the present invention; referring to fig. 6, the detecting device includes: a hall element 10 and a processing unit 20; the processing unit 20 includes:
the interval acquisition module 21 is configured to acquire a pulse signal generated by the hall element 10, and record an interval between two adjacent pulse signals;
and the rotating speed calculating module 22 is used for calculating the rotating speed of the rotor of the brushless motor according to the interval of the two adjacent pulse signals.
Specifically, the hall element 10 is disposed on the output shaft portion of the brushless motor rotor. The hall element 10 is a magnetic sensor based on the hall effect, and can detect a magnetic field and a change in the magnetic field. Alternatively, the hall element 10 is connected to the processing unit 20, and the hall element 10 detects a magnetic substance in the rotor of the brushless motor, generates a high level signal when detecting the magnetic substance, and generates a low level signal when not detecting the magnetic substance. That is, the hall element 10 can generate a pulse signal with alternating high and low levels during the rotation of the rotor of the brushless motor. For example, the operating voltage of the hall sensor is 5V, and when the magnetic substance is detected, a high-level signal is generated, that is, a voltage of 5V is output; the non-detection of the magnetic substance generates a low level signal, i.e., a 0V voltage is output. The processing unit 20 acquires the pulse signals generated by the hall element 10 and records the interval between two adjacent pulse signals. And calculating the rotating speed of the rotor of the brushless motor according to the interval of two adjacent pulse signals. The rotating speed of the rotor is obtained by calculating the number of the pulse signals generated by the Hall element 10 in the prior art, and the rotating speed of the rotor is obtained by calculating the interval between the adjacent pulse signals generated by the Hall element 10, so that the problem that the resolution of a Hall sensor is low and the detection of low rotating speed cannot be met when the rotating speed is low is solved, and the rotating speed detection of the brushless motor at low rotating speed is realized.
Optionally, fig. 7 is a block diagram of a structure of a low-speed detection apparatus of a brushless motor according to a third embodiment of the present invention; referring to fig. 7, the processing unit 20 is a single chip microcomputer, the processing unit is provided with a timer port and a timer 23, and the hall element 10 is connected with the timer port; the timer 23 is configured to capture and read a pulse signal generated by the hall sensor, and record a time of high-low level transition of two adjacent pulse signals, and the interval obtaining module is further configured to obtain an interval according to the time of high-low level transition of two adjacent pulse signals.
Specifically, after the timer 23 records the time of the high-low level transition of two adjacent pulse signals, the interval obtaining module 21 on the processing unit may calculate the obtaining interval according to the time of the high-low level transition of two adjacent pulse signals. Therefore, the single chip microcomputer captures and reads the waveform of the pulse signal generated by the Hall element 10 when the rotor rotates through the function of the timer 23, and after the time of adjacent high and low level jumping is recorded, the single chip microcomputer calculates and obtains an interval, namely the time difference of adjacent high and low level jumping according to the time of the high and low level jumping of two adjacent pulse signals through a calculation function. The high-low level jump may be a jump from high level to low level, or a jump from low level to high level. The faster the speed, the smaller the time difference. The slower the speed, the larger the time difference. If the time difference between two adjacent pulse signals is larger and larger, the rotating speed of the rotor of the brushless motor is in deceleration motion. If the time difference between the two adjacent pulse signals is smaller and smaller, the rotating speed of the rotor of the brushless motor is accelerated. If the obtained time difference of the two adjacent pulse signals is equal, the rotating speed of the rotor of the brushless motor does uniform rotating speed motion.
Optionally, fig. 8 is a block diagram of another structure of a low-speed detection apparatus for a brushless motor according to a third embodiment of the present invention, referring to fig. 8, the number of hall elements 10 is at least two, and the hall elements are spaced apart from each other and disposed on an output shaft portion of a rotor of the brushless motor, and the processing unit 20 is further configured to determine a rotation speed direction of the rotor of the brushless motor according to a phase difference between pulse signals generated by the at least two hall elements 10.
The embodiment of the invention provides a speed detection device of a brushless motor, which comprises: a Hall element; and the processing unit is used for acquiring the pulse signals generated by the Hall element, recording the interval between two adjacent pulse signals and calculating the rotating speed of the rotor of the brushless motor according to the interval between two adjacent pulse signals. The rotating speed of the rotor is obtained by calculating the number of the pulse signals generated by the Hall element in the prior art, the rotating speed of the rotor is obtained by calculating the interval between the adjacent pulse signals generated by the Hall element, low-speed detection is realized at the detection end in a software mode, a hardware circuit electrically adjusted by the brushless motor is not required to be changed, the problem that when the rotating speed is low, the resolution ratio of the Hall sensor is low, the detection of the low rotating speed cannot be met is solved, and therefore the rotating speed detection of the brushless motor at the low rotating speed is realized.
It is to be noted that the foregoing is only illustrative of the preferred embodiments of the present invention and the technical principles employed. It will be understood by those skilled in the art that the present invention is not limited to the particular embodiments described herein, but is capable of various obvious changes, rearrangements and substitutions as will now become apparent to those skilled in the art without departing from the scope of the invention. Therefore, although the present invention has been described in greater detail by the above embodiments, the present invention is not limited to the above embodiments, and may include other equivalent embodiments without departing from the spirit of the present invention, and the scope of the present invention is determined by the scope of the appended claims.
Claims (10)
1. A low-speed detection method of a brushless motor, comprising:
acquiring pulse signals generated by a Hall element, and recording the interval between two adjacent pulse signals;
and calculating the rotating speed of the rotor of the brushless motor according to the interval of two adjacent pulse signals.
2. The low speed detection method of a brushless motor according to claim 1, wherein the hall element detects a magnetic substance in a rotor of the brushless motor and generates a high level signal when the magnetic substance is detected and generates a low level signal when the magnetic substance is not detected.
3. The low-speed detection method of a brushless motor according to claim 2, wherein the hall element is connected to a processing unit; the processing unit is a single chip microcomputer, the processing unit is provided with a timer port and a timer, and the Hall element is connected with the timer port; the acquiring the pulse signals generated by the hall element and recording the interval between two adjacent pulse signals includes:
the timer captures and reads the pulse signal generated by the Hall sensor; recording the time of level jump of two adjacent pulse signals;
and acquiring the interval according to the time of level jump of two adjacent pulse signals.
4. The method for detecting a low speed of a brushless motor according to claim 3, wherein said calculating a rotation speed of a rotor of the brushless motor according to an interval between two adjacent pulse signals comprises:
the processing unit calculates the rotating speed of the rotor of the brushless motor according to the interval of the corresponding moments when two adjacent high levels jump to low levels;
or the processing unit calculates the rotating speed of the rotor of the brushless motor according to the interval of the corresponding time when two adjacent moments jump from the low level to the high level.
5. The method of claim 4, wherein the processing unit calculates the rotation speed of the rotor of the brushless motor according to the interval between two adjacent times corresponding to the jump from the high level to the low level, and determines the rotation speed based on:
P/(T2-T1), where v is the rotation speed of the brushless motor rotor; p is a correction coefficient which is obtained based on the product of the rotating speed of the rotor obtained by an external speed measuring tool and the high-low level jump time difference corresponding to the measured rotating speed; t1 is the time point of transition from high level to low level, and T2 is the time point of transition from high level to low level;
the processing unit calculates the rotating speed of the rotor of the brushless motor according to the interval of the corresponding time of two adjacent jumps from the low level to the high level, and the rotating speed is determined based on the following steps:
P/(T5-T4), where v is the rotation speed of the brushless motor rotor; p is the correction coefficient; t4 is the time point of transition from low level to high level, and T5 is the time point of transition from low level to high level.
6. The method of claim 3, wherein the number of the hall elements is at least two, and the hall elements are spaced apart from each other at an output shaft portion of the rotor of the brushless motor, and the method further comprises:
the processing unit determines the rotating speed direction of the brushless motor rotor according to the phase difference of the pulse signals generated by at least two Hall elements.
7. The speed detection device of the brushless motor is characterized by comprising a Hall element and a processing unit; the processing unit includes:
the interval acquisition module is used for acquiring pulse signals generated by the Hall element and recording the interval between two adjacent pulse signals;
and the rotating speed calculating module is used for calculating the rotating speed of the rotor of the brushless motor according to the interval of two adjacent pulse signals.
8. The low-speed detection apparatus of a brushless motor according to claim 7, wherein the hall element is configured to generate a high level signal when the magnetic substance is detected and generate a low level signal when the magnetic substance is not detected.
9. The apparatus of claim 8, wherein the processing unit further comprises a timer and a timer port, the hall element being connected to the timer port;
the timer is used for capturing and reading pulse signals generated by the Hall sensor and recording the high-low level jumping time of two adjacent pulse signals;
the interval acquisition module is further configured to acquire the interval according to a time of level jump of two adjacent pulse signals.
10. The apparatus of claim 9, wherein the number of the hall elements is at least two, and the hall elements are spaced apart from each other at an output shaft portion of the rotor of the brushless motor, and the processing unit is further configured to determine a rotation speed direction of the rotor of the brushless motor according to a phase difference between pulse signals generated by the at least two hall elements.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202011289033.4A CN112468028A (en) | 2020-11-17 | 2020-11-17 | Low-speed detection method and device of brushless motor |
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| CN202011289033.4A CN112468028A (en) | 2020-11-17 | 2020-11-17 | Low-speed detection method and device of brushless motor |
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| WO2008146453A1 (en) * | 2007-05-18 | 2008-12-04 | Ntn Corporation | Motor-integrated magnetic bearing |
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