WO2019185018A1 - Vacuum cleaner, and counter electromotive force zero-cross detection method, apparatus and control system of motor - Google Patents

Vacuum cleaner, and counter electromotive force zero-cross detection method, apparatus and control system of motor Download PDF

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Publication number
WO2019185018A1
WO2019185018A1 PCT/CN2019/080423 CN2019080423W WO2019185018A1 WO 2019185018 A1 WO2019185018 A1 WO 2019185018A1 CN 2019080423 W CN2019080423 W CN 2019080423W WO 2019185018 A1 WO2019185018 A1 WO 2019185018A1
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WIPO (PCT)
Prior art keywords
zero
sampling
motor
emf
brushless
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PCT/CN2019/080423
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French (fr)
Chinese (zh)
Inventor
王浩东
万德康
吴偏偏
Original Assignee
江苏美的清洁电器股份有限公司
美的集团股份有限公司
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Priority to CN201810296965.8A priority Critical patent/CN108448954A/en
Priority to CN201810296965.8 priority
Priority to CN201810296820.8 priority
Priority to CN201810294383.6A priority patent/CN108631658A/en
Priority to CN201810295559.X priority
Priority to CN201810294383.6 priority
Priority to CN201810295559.XA priority patent/CN108606724A/en
Priority to CN201810296820.8A priority patent/CN108448953B/en
Application filed by 江苏美的清洁电器股份有限公司, 美的集团股份有限公司 filed Critical 江苏美的清洁电器股份有限公司
Publication of WO2019185018A1 publication Critical patent/WO2019185018A1/en

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    • HELECTRICITY
    • H02GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02PCONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS
    • H02P6/00Arrangements for controlling synchronous motors or other dynamo-electric motors using electronic commutation dependent on the rotor position; Electronic commutators therefor
    • H02P6/14Electronic commutators
    • H02P6/16Circuit arrangements for detecting position
    • H02P6/18Circuit arrangements for detecting position without separate position detecting elements
    • H02P6/182Circuit arrangements for detecting position without separate position detecting elements using back-emf in windings

Abstract

Disclosed are a vacuum cleaner, and a counter electromotive force zero-cross detection method, apparatus and control system of a motor. The method comprises: in the process of controlling the motor, when a duty ratio of a PWM control signal is greater than a first preset duty ratio, performing continuous multiple sampling on a counter electromotive force within a high-level time period of a PWM control cycle by means of a single channel of an ADC module, and determining whether the counter electromotive force is in zero-crossing in the process of sampling according to the last sampling result; or performing multiple sampling on the counter electromotive force within the high-level time period by means of an FIFO multi-channel sampling function of the ADC module, and determining whether the counter electromotive force is in zero-crossing after sampling is completed according to the sampling result; or triggering an ADC single channel to perform sampling on the counter electromotive force at preset intervals within the PWM control cycle by means of a hardware triggering mode, and determining whether the counter electromotive force is in zero-crossing after sampling is completed each time according to the sampling result. According to the method, the counter electromotive force zero-cross point can be detected timely and accurately, stable operation of the motor at the extremely high operating speed can be ensured, and costs are low.

Description

Method, device and control system for detecting back-force zero-crossing of vacuum cleaner and motor

Cross-reference to related applications

The present application is based on a Chinese patent application filed on Jan. 30, 2018, the entire disclosure of which is hereby incorporated by reference. This application is hereby incorporated by reference.

Technical field

The invention relates to the technical field of motor control, in particular to a method for detecting a zero-crossing zero-crossing of a brushless DC motor, a device for detecting a zero-crossing zero-crossing of a brushless DC motor, a control system for a brushless DC motor and a control system vacuum cleaner.

Background technique

At present, in the field of sensorless drive control technology of brushless DC motor, there are many methods for detecting the rotor position of the motor, among which the back EMF zero-crossing method is simple and effective and widely used. The basic principle of the back-EMF zero-crossing method is that when the back-EMF of a phase winding of a brushless DC motor crosses zero, the straight axis of the rotor coincides with the axis of the phase winding. Therefore, it is only necessary to judge the zero-crossing point of the back-EM of each phase winding. Know the rotor position of the motor.

In the related art, there are two methods for detecting zero-crossing zero-crossing: First, an ADC (Analog-to-Digital Converter) module is used to sample each PWM (Pulse Width Modulation) control period. The terminal voltage of the floating phase of the brushless DC motor is once compared, and then the sampling result is compared with the reference voltage to determine whether a zero crossing occurs. Second, the external comparator is added, and the terminal voltage of the floating phase of the brushless DC motor and the reference voltage are compared by hardware. Relationship, to achieve anti-potential zero-crossing detection.

However, the above detection method has the following disadvantages: 1) When the method 1 is used to perform the back-EMF zero-crossing detection, the detected back-EMF zero-crossing time lags the actual back-EMF zero-crossing time by about one PWM period, in the brushless DC motor. The rotation speed is low, when the duty ratio of the PWM control signal is small, there are multiple PWM cycles in one commutation interval, and the hysteresis of one PWM period has less influence on the commutation of the brushless DC motor, but when the speed of the brushless DC motor is small, When higher, the number of PWM cycles in one commutation interval is small, and the back-zero zero-crossing detection hysteresis may cause the commutation hysteresis of the brushless DC motor, thus affecting the stability of the brushless DC motor; 2) Adopting method 2 When the back-EMF zero-crossing detection is performed, the external comparator is added, which results in higher cost.

Summary of the invention

The present application aims to solve at least one of the technical problems in the related art to some extent. Therefore, the first object of the present application is to provide a method for detecting the back-EMF zero-crossing of a brushless DC motor, which can not only detect the zero-crossing point of the back EMF in a timely and accurate manner, but also ensure that the motor runs stably at a very high speed, and does not need to Additional comparators can reduce costs.

A second object of the present application is to provide a method for detecting a back-EMF zero-crossing of another brushless DC motor.

A third object of the present application is to propose a non-transitory computer readable storage medium.

A fourth object of the present application is to provide a back EMF zero crossing detecting device for a brushless DC motor.

A fifth object of the present application is to provide a control system for a brushless DC motor.

A sixth object of the present application is to provide a vacuum cleaner.

To achieve the above objective, the first aspect of the present application provides a method for detecting a back-EMF zero-crossing of a brushless DC motor, comprising the steps of: acquiring a PWM control signal of the brushless DC motor in each PWM control period. a duty ratio; detecting and confirming that the duty ratio is greater than the first predetermined duty ratio, performing any one of the following operations: a single pass through the ADC module during a high level of the PWM control period Channels continuously sample the back EMF of the brushless DC motor continuously, and perform zero-crossing detection on the back EMF according to the last sampling result during the sampling process; during the high-level time of the PWM control period The back electromotive force of the brushless DC motor is sampled multiple times by the FIFO multi-channel sampling function of the ADC module, and after the sampling is completed, the back EMF is subjected to zero-cross detection according to the sampling result; The hardware trigger mode triggers the ADC single channel to sample the back EMF of the brushless DC motor every preset time interval, and after the sampling is completed, the back EMF is generated according to the sampling result. Zero crossing detection is performed, wherein the PWM control signal is a centrally symmetric PWM control signal.

According to the back EMF zero-crossing detection method of the brushless DC motor according to the embodiment of the present application, the duty ratio of the PWM control signal of the brushless DC motor is obtained in each PWM control period, and the duty ratio is detected and confirmed to be greater than the first preset. The duty ratio is continuously sampled by the single-channel of the ADC module for the back EMF of the brushless DC motor during the high-level period of the PWM control period, and the back EMF is performed according to the previous sampling result during the sampling process. Zero detection, or multi-sample the back EMF of the brushless DC motor through the FIFO multi-channel sampling function of the ADC module during the high-level period of the PWM control cycle, and zero-cross the back EMF according to the sampling result after the sampling is completed. Detect, or trigger the ADC single channel at a preset time interval to sample the back EMF of the brushless DC motor during the PWM control cycle, and perform zero-crossing detection of the back EMF according to the sampling result after each sampling is completed. Wherein, the PWM control signal is a centrally symmetric PWM control signal. Therefore, not only can the zero-crossing point of the back EMF be detected in time and accurately, the motor can be stably operated at a very high speed, and the comparator can be added without further increase of cost.

In order to achieve the above object, the second aspect of the present application provides another method for detecting a back-EMF zero-crossing of a brushless DC motor, comprising the steps of: acquiring PWM control of the brushless DC motor in each PWM control period. a duty ratio of the signal; detecting and confirming that the duty ratio is greater than the first predetermined duty ratio, and the single-channel pair of the brushless DC motor is passed through the ADC module during a high level period of the PWM control period The back EMF is sampled multiple times in succession, and the back EMF is zero-crossed based on the last sampling result during the sampling process.

According to the back EMF zero-crossing detection method of the brushless DC motor according to the embodiment of the present application, the duty ratio of the PWM control signal of the brushless DC motor is obtained in each PWM control period, and it is detected and determined whether the duty ratio is greater than the first pre- Set the duty ratio, continuously sample the back EMF of the brushless DC motor through the single channel of the ADC module during the high period of the PWM control period, and perform the back EMF according to the previous sampling result during the sampling process. Zero crossing detection.

In order to achieve the above object, a third aspect of the present application provides a non-transitory computer readable storage medium having stored thereon a computer program, which is implemented by a processor to implement the back EMF of the brushless DC motor described above. Zero detection method.

According to the non-transitory computer readable storage medium of the embodiment of the present application, by performing the above-described back-EMF zero-crossing detection method of the brushless DC motor, not only the back-zero crossing point can be detected in time and accurately, but also the motor is stably operated at the pole. High speed and no additional comparators can reduce costs.

In order to achieve the above object, a back EMF zero-crossing detecting device for a brushless DC motor according to a fourth aspect of the present application includes: an acquiring unit, configured to acquire the brushless DC motor in each PWM control period. a duty ratio of the PWM control signal; a confirmation unit, configured to detect and confirm that the duty ratio is greater than a first preset duty ratio; and a sampling unit configured to perform any one of the following operations according to the confirmation result of the confirmation unit Generating: the back EMF of the brushless DC motor is continuously sampled multiple times through a single channel of the ADC module during a high level period of the PWM control period, and in the process of sampling, according to the last sampling result The back EMF performs zero-crossing detection; the back-EM potential of the brushless DC motor is sampled multiple times by the FIFO multi-channel sampling function of the ADC module during the high-level period of the PWM control period, and is sampled according to the sampling after the sampling is completed. As a result, a zero-crossing detection is performed on the back-EM potential; in the PWM control period, the ADC single-channel is triggered by a hardware trigger to counter the brushless DC motor every preset time interval. The potential is sampled, and after each sampling is completed, the back EMF is zero-crossed according to the sampling result, wherein the PWM control signal is a centrally symmetric PWM control signal.

According to the back EMF zero-crossing detecting device of the brushless DC motor according to the embodiment of the present application, the duty ratio of the PWM control signal of the brushless DC motor is obtained by the acquiring unit in each PWM control period, and is detected and confirmed by the confirming unit. The empty ratio is greater than the first preset duty ratio, and the back potential of the brushless DC motor is continuously passed through the single channel of the ADC module in the high level of the PWM control period by the sampling unit according to the confirmation result of the confirmation unit. Sampling, and during the sampling process, the back-EMF is zero-crossed based on the previous sampling result, or the back-EMF of the brushless DC motor is performed by the FIFO multi-channel sampling function of the ADC module during the high-level period of the PWM control cycle. Multiple sampling, and after the sampling is completed, the back EMF is zero-crossed according to the sampling result, or the ADC single-channel is triggered by the hardware trigger mode in the PWM control period to sample the back EMF of the brushless DC motor every preset time interval. And after each sampling is completed, the back EMF is zero-crossed according to the sampling result, wherein the PWM control signal is center-symmetrical PWM control signal. Therefore, not only can the zero-crossing point of the back EMF be detected in time and accurately, the motor can be stably operated at a very high speed, and the comparator can be added without further increase of cost.

In order to achieve the above object, a fifth aspect of the present application provides a control system for a brushless DC motor, which comprises the above-described back-EMF zero-crossing detecting device of a brushless DC motor.

According to the control system of the brushless DC motor according to the embodiment of the present application, the back EMF zero-crossing detecting device of the brushless DC motor described above can not only detect the zero-crossing point of the back EMF in a timely and accurate manner, but also ensure that the motor runs stably at a very high speed. And without the need to add additional comparators, you can reduce costs.

In order to achieve the above object, a sixth aspect of the present application proposes a vacuum cleaner comprising the above control system of a brushless DC motor.

According to the vacuum cleaner of the embodiment of the present application, the control system of the brushless DC motor can not only detect the zero-crossing point of the back EMF in time and accurately, but also ensure that the motor runs stably at a very high speed, and the comparator can be reduced without additional amplifier. cost.

DRAWINGS

1 is a flow chart of a method for detecting a back-EMF zero-crossing of a brushless DC motor according to an embodiment of the present application;

Figure 2a is a terminal voltage waveform diagram of one cycle of phase A;

Figure 2b is a waveform diagram of the terminal voltage of the phase A suspension phase;

3 is a schematic diagram of a back-EMF zero-crossing detection of a brushless DC motor in the related art;

4 is a schematic diagram of a back-EMF zero-crossing detection of a brushless DC motor according to an embodiment of the first aspect of the present application;

5 is a flow chart of a method for detecting a back-EMF zero-crossing of a brushless DC motor according to an embodiment of the first aspect of the present application;

6 is a schematic diagram of a back-EMF zero-crossing detection of a brushless DC motor at an extremely high rotational speed according to an embodiment of the present application;

7a is a schematic diagram of a back-EMF zero-crossing detection of a brushless DC motor according to an embodiment of the second aspect of the present application;

7b is a schematic diagram of a back-EMF zero-crossing detection of a brushless DC motor according to an embodiment of the third aspect of the present application;

8a-8c are flowcharts of a method for detecting a back-EMF zero-crossing of a brushless DC motor according to an embodiment of the second aspect of the present application;

9 is a schematic diagram of a back-EMF zero-crossing detection of a brushless DC motor at an extremely high rotational speed according to another embodiment of the present application;

10 is a schematic diagram of a back-EMF zero-crossing detection of a brushless DC motor according to an embodiment of the fourth aspect of the present application;

11 is a flow chart of a method for detecting a back-EMF zero-crossing of a brushless DC motor according to a specific embodiment of the third aspect of the present application;

12 is a schematic diagram of a back-EMF zero-crossing detection of a brushless DC motor at an extremely high rotational speed according to still another embodiment of the present application;

13 is a schematic diagram of a back-EMF zero-crossing detection of a brushless DC motor according to an embodiment of the fifth aspect of the present application;

14a is a flow chart of a method for detecting a back-EMF zero-crossing of a brushless DC motor according to an embodiment of the fourth aspect of the present application;

14b is a flowchart of a method for detecting a back-EMF zero-crossing of a brushless DC motor according to an embodiment of the fifth aspect of the present application;

15 is a flow chart of a method for detecting a back-EMF zero-crossing of another brushless DC motor according to an embodiment of the present application;

16 is a block schematic diagram of a back EMF zero crossing detecting device of a brushless DC motor according to an embodiment of the present application.

detailed description

The embodiments of the present application are described in detail below, and the examples of the embodiments are illustrated in the drawings, wherein the same or similar reference numerals are used to refer to the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are intended to be illustrative, and are not to be construed as limiting.

A method for detecting a back-EMF zero-crossing of a brushless DC motor according to an embodiment of the present application, a non-transitory computer readable storage medium, a back EMF zero-crossing detecting device for a brushless DC motor, and a brushless DC motor are described below with reference to the accompanying drawings. Control system and vacuum cleaner.

1 is a flow chart of a method for detecting a back-EMF zero-crossing of a brushless DC motor according to an embodiment of the present application. As shown in FIG. 1 , the method for detecting the zero-potential zero-crossing of the brushless DC motor according to the embodiment of the present application includes the following steps:

S1, in the process of controlling the brushless DC motor, obtain the duty ratio of the PWM control signal of the brushless DC motor in each PWM control period, and determine whether the duty ratio is greater than the first duty ratio.

S2, if the duty ratio is greater than the first preset duty ratio, perform any one of step S21, step S22, and step S23, where

Step S21 is to continuously sample the back EMF of the brushless DC motor through the single channel of the ADC module during the high level of the PWM control period, and determine whether the back EMF has passed according to the previous sampling result during the sampling process. zero.

Step S22 is: performing multi-sampling on the back electromotive force of the brushless DC motor through the FIFO multi-channel sampling function of the ADC module during the high-level period of the PWM control period, and determining whether the back-EM potential is zero-crossed according to the sampling result after the sampling is completed. .

Step S23 is: in the PWM control period, triggering the ADC single channel to sample the back EMF of the brushless DC motor by the hardware trigger mode, and determining whether the back EMF is zero or not according to the sampling result after each sampling is completed. . The PWM control signal is a centrally symmetric PWM control signal.

According to an embodiment of the present application, if the duty ratio is less than the second preset duty ratio, the back EMF of the brushless DC motor is sampled once by the conventional back EMF sampling method during the high level period of the PWM control period. And determining whether the back EMF is zero or not according to the sampling result, wherein the second preset duty ratio is less than the first preset duty ratio, and the calibration may be performed according to actual conditions.

Specifically, the current back-EMF zero-crossing detection compares the relationship between the suspended phase terminal voltage and the reference voltage. Taking phase A as an example, the voltage waveform of the A phase winding terminal in one cycle is as shown in Fig. 2a, in which phase A is suspended during BC and CB, and its terminal voltage waveform is as shown in Fig. 2b. During PWM turn-on, phase A voltage U A =e A +1/2U DC , when U A =1/2U DC , e A =0, which is the time when A is opposite to zero potential; during PWM turn-off, The phase A voltage U A = e A , when U A =0, is the moment when A is opposite to zero. Therefore, the back-EMF zero-crossing detection is performed during PWM turn-on, the reference voltage selects 1/2U DC , the back-EMF zero-crossing detection is performed during PWM turn-off, and the reference voltage selects 0V.

In the related art, when the ADC module is used to sample the terminal voltage of the suspended phase in each PWM control period, and the sampling result is compared with the reference voltage to determine whether the back EMF is zero crossing, the back EMF is detected during the PWM turn-on period. Zero crossing is an example. As shown in FIG. 2, during the BC turn-on period, the voltage of the A-phase terminal is increasing, and the voltage of the A-phase terminal is once sampled during each PWM turn-on period, and compared with the reference voltage, at time a1 in FIG. 2b. U A <1/2U DC , the back EMF has not crossed zero. At the moment a2 of the next PWM control period, U A >1/2U DC , at this time, the back EMF has been detected to have passed zero; similarly, during CB conduction, The voltage at phase A shows a downward trend. At time b2, U A > 1/2 U DC , the back EMF does not cross zero, and at time b3, U A < 1/2 U DC , at which time the back EMF has been detected to have passed zero.

The above-mentioned detected back-EMF zero-crossing time lags the actual back-EMF zero-crossing time by about one PWM control period. In the case of a lower rotation speed (lower duty ratio), there are multiple PWM control periods in one commutation interval. Therefore, a PWM control cycle lags less on the commutation. However, when the brushless DC motor is running at extremely high speed, such as 100000RPM (1 pole), the time of one phase sector is 100us, and the PWM control period is 50us (ie 20KHz, PWM of brushless DC motor). The frequency of the control signal is generally in the range of 5 to 30 KHz, and the increase will cause adverse effects on the switching loss, efficiency and heat dissipation of the power switch tube. At this time, there are at most 2 PWM control periods in one commutation interval, and each PWM The control cycle only performs one-time zero-crossing sampling, so it is impossible to know in time whether the back-EM potential is zero-crossing, and it is easy to cause the brushless DC motor to lose synchronization due to the large back-lag detection hysteresis.

Specifically, as shown in FIG. 3, when the brushless DC motor is operated at a very high rotational speed, there are only two PWM control periods in one commutation interval, if according to the conventional back EMF sampling method, that is, in the two PWM control periods The back-potential AD sampling is performed internally, corresponding to the times c1 and c2, respectively, and the actual back-potential zero-crossing occurs after the c1 time, so the back-EMF zero-crossing cannot be detected in time during the first PWM control period. The back EMF zero crossing is detected at the c2 time of the two PWM control periods, and the true back EMF zero crossing point is about 1 PWM control period (about 1/2 commutation interval) at c2, causing the back EMF zero crossing detection lag. This in turn leads to a commutation hysteresis, causing undesirable conditions such as large current ripple or even loss of step.

Therefore, in the embodiment of the present application, the operation of the brushless DC motor can be divided into two phases, namely a low speed phase and a high speed phase, and further, according to the duty ratio of the PWM control signal, the brushless DC motor can be The operation is divided into a low duty cycle phase and a high duty cycle phase. Wherein, in the low duty cycle phase (ie, the low speed phase), the conventional back EMF sampling method is still used, for example, the back EMF AD sampling is performed in the high level time of each PWM control period, and the inverse is determined according to the sampling result. Whether the potential is zero. And when the duty ratio rises above the first preset duty cycle, enters a high duty cycle phase (ie, a high speed phase) during which a high level time is in each PWM control cycle. Using the single channel of the ADC module to continuously sample the back EMF of the brushless DC motor, and judge whether the back EMF is zero-crossing according to the previous sampling result during the sampling process, or use the FIFO multi-channel sampling function of the ADC module. The back electromotive force of the brushless DC motor is sampled multiple times, and after the sampling is completed, it is judged whether the back EMF is zero or zero according to the sampling result, or the ADC single channel is triggered by the hardware trigger mode for the first preset time in the whole PWM control period. The back electromotive force of the brushless DC motor is sampled, and after each sampling is completed, it is judged whether the back EMF is zero or not according to the sampling result. When the duty cycle drops again below the second preset duty cycle, a conventional back EMF sampling method is used, wherein the second preset duty cycle is less than the first preset duty cycle.

Since the zero-crossing detection hysteresis of the low duty cycle stage has little effect on the commutation of the brushless DC motor, in the low-speed operation phase of the brushless DC motor, the conventional back-potential sampling method can meet the control demand, while at the high In the duty cycle phase, the back EMF can be sampled multiple times in a high time period of each PWM control cycle by using a single channel of the ADC module, or by using the FIFO multi-channel sampling function of the ADC module, and in each PWM control During the high period of the cycle, the counter back EMF is continuously sampled multiple times, or the ADC single channel is triggered by the hardware trigger mode to sample the back EMF multiple times in each PWM control period, thus ensuring the timeliness and accuracy of the back EMF zero crossing detection. It can support the brushless DC motor to operate stably in a very high speed range, and without additional amplifiers, it can reduce the cost and reduce the size of the controller PCB.

The following is a detailed description of how to continuously sample the back EMF of the brushless DC motor through the single channel of the ADC module in the high level time of the PWM control period in conjunction with FIG. 4-6, and according to the previous time during the sampling process. The sampling result determines whether the back EMF is zero crossing.

According to an embodiment of the present application, the back EMF of the brushless DC motor is continuously sampled multiple times through a single channel of the ADC module during a high level period of the PWM control period, and is judged according to the last sampling result in the sampling process. Whether the back EMF is zero-crossing, including: judging whether to enter the anti-potential zero-crossing detection phase; if yes, obtaining the bus voltage of the brushless DC motor, and configuring the single channel of the ADC module as the AD channel corresponding to the current suspended phase terminal voltage, And triggering the single channel of the ADC module to perform the first sampling of the back EMF of the brushless DC motor; after the first sampling is completed, the first sampling result is obtained, and the single channel of the ADC module is triggered to the opposite of the brushless DC motor. The potential is sampled a second time, and in the process of the second sampling, the back-potential is judged to be zero-crossed according to the first sampling result and the bus voltage; if the back-potential is zero-crossed, the back-potential zero-crossing detection phase is exited.

According to an embodiment of the present application, if the back EMF does not cross zero, after the i-1th sampling is completed, the i-1th sampling result is obtained, and the single channel of the ADC module is triggered to the back electromotive force of the brushless DC motor. The i-th sampling is performed, and in the process of the i-th sampling, whether the back-EM potential is zero-crossed according to the i-1th sampling result and the bus voltage is determined, until the back-potential zero-crossing is determined or the sampling times are greater than or equal to the preset number of times. The potential zero crossing detection phase, where i is an integer greater than or equal to 3.

According to an embodiment of the present application, the back EMF zero-crossing detection method of the brushless DC motor may further include: determining whether the current time is a high-level start time of the PWM control period; if the current time is a high-level start of the PWM control period At the time, the bus voltage AD sampling is triggered after the first preset time is delayed, and the back-potential zero-crossing detection phase is entered after the bus voltage AD sampling is completed.

Specifically, referring to FIG. 4, in the process of controlling the brushless DC motor by using the PWM control signal, the counting unit of the PWM can be used to determine whether the current time is the high-level start time of the PWM control period, and if so, Then, the bus voltage AD sampling is triggered after delaying the first preset time (the length of the time is configured by a software program, for example, 4us) (1/2 of the bus voltage is used as the reference voltage for the back-EMF zero-cross detection). Wherein, the bus voltage is set to be sampled after the first preset time to prevent the bus voltage sampling from being inaccurate due to the influence of the power switch. In the first preset time, the duty ratio of the PWM control signal can be compared and judged. If the duty ratio is less than the second preset duty ratio, the conventional back EMF sampling method is used to determine whether the back EMF is zero-crossing, such as After sampling the bus voltage AD, it enters the back-EMF zero-crossing detection stage. At this time, the single-channel of the ADC module is used to sample the suspended phase terminal voltage once, and the sampling result is compared with the bus voltage to determine whether the back-EM potential has passed. Zero; if the duty ratio is greater than the first preset duty cycle, then after the sampling of the bus voltage AD is completed, the counter-potential zero-crossing detection phase is entered. At this time, the single-channel of the ADC module is used to continuously perform the back electromotive force of the brushless DC motor. Sampling multiple times, and judging whether the back EMF is zero-crossing according to the previous sampling result during the sampling process.

Specifically, referring to FIG. 4, the AD interrupt is automatically generated after the bus voltage AD sampling is completed (about 1 us), and after the AD interrupt is entered, the AD sampling result of the bus voltage is read, and the single channel configuration of the ADC module is configured. It is the AD channel corresponding to the current suspended phase terminal voltage, in preparation for subsequent successive back EMF sampling. First, the single channel of the ADC module is triggered to first sample the back EMF of the brushless DC motor, and after the first sampling is completed, the first sampling result is read, and the single channel pair brushless DC motor of the ADC module is triggered at the same time. The back EMF is sampled a second time, and in the second sampling process, the first sampling result is compared with the bus voltage to determine whether the back EMF is zero crossing. If the back EMF crosses zero, the AD interrupt is exited, the current PWM The back EMF zero crossing detection of the control cycle ends.

If the back EMF does not cross zero, after the second sampling is finished, the second sampling result is read, and the single channel of the ADC module is triggered to perform the third sampling of the back EMF of the brushless DC motor, and the third time During the sampling process, it is judged whether the back EMF is zero or not according to the second sampling result and the bus voltage. If the back EMF crosses zero, the AD interrupt is exited; if the back EMF does not cross zero, after the third sampling is finished, the reading is performed. The result of three samplings, and triggering the single channel of the ADC module to perform the fourth sampling of the back EMF of the brushless DC motor, ..., after the completion of the i-1th sampling, the i-1th sampling result is obtained, and the ADC is triggered at the same time. The single channel of the module performs the i-th sampling of the back electromotive force of the brushless DC motor, and judges whether the back EMF is zero-crossing according to the i-1th sampling result and the bus voltage during the i-th sampling process until the back electromotive force is judged. Zero crossing or sampling times greater than or equal to the preset number of times, exit the AD interrupt.

The above process is repeated at the beginning of the next PWM control cycle.

In the above embodiment, the i-1th sampling result is acquired when the i-1th sampling is completed, and the sampling of the i th back electric potential is triggered at the same time, so that the back EMF zero crossing is judged by using the i-1th sampling result. At the same time, the sampling and conversion of the i-th back EMF is also performed automatically, which is beneficial to collecting as many back potentials as possible in the high-level time of the PWM control period. This continuous single-channel back EMF AD sampling, The back-EMF zero-crossing judgment can be performed when each single-channel back EMF sampling is completed, so that the back-EMF zero-crossing can be detected in time, which makes the commutation more precise, and thus the brushless DC motor can stably operate at extremely high speed. And without the need to add additional comparators, you can reduce costs.

It should be noted that the preset number of times in the foregoing embodiment may be calibrated according to the time required for determining the single-channel AD sampling and the back-EMF zero-crossing and the high-level time of the current PWM control period. For example, suppose that the time required for a single-channel AD sampling and back-EMF zero-crossing determination is Δt, and the high-level time of the current PWM control period is T, then the number of consecutive single-channel back EMF acquisition and zero-crossing judgments is N=T/ Δt, that is, the preset number of times is T/Δt (take an integer, less than one round), when the sampling number is greater than or equal to T/Δt, exit the back EMF zero-crossing detection phase, and the back EMF zero-cross detection of the current PWM control period ends. .

As shown in FIG. 5, the back EMF zero-crossing detection method of the brushless DC motor may include the following steps:

S101, reading the bus voltage AD sampling result, and configuring the single channel back EMF AD sampling, and setting the cumulative count of the single channel back EMF sampling to zero.

S102. Determine whether the current back EMF AD sampling ends. If yes, step S103 is performed; if no, step S102 is continued.

S103. Determine whether the current back electromotive sampling time is less than N. If yes, step S104 is performed; if not, the back-potential zero-crossing detection of the current PWM control period ends, and the AD interrupt is exited.

S104, reading the back potential AD sampling result, simultaneously triggering the next back EMF AD sampling, and adding the current single channel back EMF sampling cumulative number by one.

S105. Determine whether the back EMF is zero-crossing according to the back-potential AD sampling result. If so, the back EMF zero crossing detection of the current PWM control period ends, and the AD interrupt is exited; if not, the process returns to step S102.

6 is a schematic diagram of the back-potential zero-crossing detection of a brushless DC motor at a very high rotational speed according to an embodiment of the present application, as shown in FIG. 6, a single-channel pair of brushless DC motors through an ADC module in one PWM control period The back EMF is continuously sampled multiple times, and the zero-crossing point of the back EMF can be detected accurately and timely, thus ensuring that the brushless DC motor can run stably at a very high speed without the need for an external comparator, thereby reducing the cost.

According to an embodiment of the present application, during the high level of the PWM control period, it is also determined whether the freewheeling time of the brushless DC motor is over, and after the freewheeling time is over, the single channel of the ADC module is used for brushless DC. The back EMF of the motor is continuously sampled multiple times, and during the sampling process, it is judged whether the back EMF is zero or not based on the previous sampling result.

Specifically, when the brushless DC motor enters a high duty cycle phase (ie, a high speed phase), in this phase, since there is a freewheeling process after the commutation of the brushless DC motor, the phase terminal voltage is suspended during the freewheeling period. Forced to pull to the bus voltage or power ground, causing some of the back EMF waveform to be annihilated, so the back EMF sampling during the freewheeling period is invalid, and the back EMF of the brushless DC motor can be continuously continuous after the end of the freewheeling time. Subsampling, which saves CPU resources. Therefore, in the high duty cycle phase, during the high time period of each PWM control period, the freewheeling time is avoided, and then the back potential of the brushless DC motor is continuously sampled multiple times by using the single channel of the ADC module, and In the process of sampling, it is judged whether the back EMF is zero or not based on the result of the previous sampling.

The following is a detailed description of how to avoid the freewheeling time in the high-level time of the PWM control period, and to continuously sample the back EMF of the brushless DC motor through the single channel of the ADC module, and sample it in combination with FIG. 7-9. In the process, it is judged whether the back EMF is zero or not based on the result of the previous sampling.

Referring to FIG. 7a - FIG. 7b, in the process of controlling the brushless DC motor by using the PWM control signal, the counting unit of the PWM can be used to determine whether the current time is the high-level start time of the PWM control period, and if so, The bus voltage AD sampling is triggered after delaying the first preset time (the length of time is configured by a software program, for example, 4 us) (1/2 of the bus voltage is used as the reference voltage for the back-EMF zero-cross detection). Wherein, the bus voltage is set to be sampled after the first preset time to prevent the bus voltage sampling from being inaccurate due to the influence of the power switch. In the first preset time, the duty ratio of the PWM control signal can be compared and judged. If the duty ratio is less than the second preset duty ratio, the conventional back EMF sampling method is used to determine whether the back EMF is zero-crossing, such as After sampling the bus voltage AD, it enters the back-EMF zero-crossing detection stage. At this time, the single-channel of the ADC module is used to sample the suspended phase terminal voltage once, and the sampling result is compared with the bus voltage to determine whether the back-EM potential has passed. Zero; if the duty ratio is greater than the first preset duty cycle, after the sampling of the bus voltage AD is completed, the counter-potential zero-crossing detection phase is entered. In this phase, the freewheeling time is avoided first, and then the ADC module is The single-channel continuously samples the back EMF of the brushless DC motor continuously, and judges whether the back EMF is zero-crossing according to the previous sampling result during the sampling process.

Specifically, referring to FIG. 7a to FIG. 7b, the AD interrupt is automatically generated after the bus voltage AD sampling is completed (about 1 us), and after the AD interrupt is entered, the AD sampling result of the bus voltage is read, and the ADC module is read. The single channel configuration is the AD channel corresponding to the current suspended phase terminal voltage, which is accurate for subsequent single-channel back EMF AD sampling. Then, according to the context of the freewheeling time and the occurrence of the AD interrupt, there are two cases.

In the first case, as shown in Figure 7a, after the incoming stream time to the AD interrupt has expired (the corresponding freewheeling time end flag has been set), a single-channel back EMF is performed multiple times in the AD interrupt. AD sampling. For the specific sampling process, refer to the sampling process shown in FIG. 4 in the foregoing embodiment. To avoid redundancy, details are not described herein.

In the second case, as shown in FIG. 7b, after the flow time to enter the AD interrupt has not ended (the corresponding free-wheeling time end flag is not set), the AD interrupt is exited, and once the free-flow time is over, the automatic escape is automatically avoided. The open stream delay interrupt TF, and the freewheeling time end flag is first set in the freewheeling delay interrupt TF, and then the single channel back EMF AD sampling is performed multiple times in succession. The specific sampling process can be referred to the foregoing, and here is not A detailed description will be given. In order to make the present application more clear to those skilled in the art, the back EMF zero-crossing detection method of the brushless DC motor will be further described below in conjunction with the specific example of the present application.

Specifically, as shown in FIG. 8a, the back EMF zero-crossing detection method of the brushless DC motor may include the following steps:

S201. Determine whether the freewheeling time ends. If yes, go to step S502; if no, exit AD interrupt.

S202, triggering single channel back EMF AD sampling.

S203. Determine whether the current back EMF AD sampling ends. If yes, step S204 is performed; if no, step S203 is continued.

S204, reading the back EMF AD sampling result.

S205. Determine whether the back EMF is zero-crossing according to the back-potential AD sampling result. If yes, go to step S207; if no, go to step S206.

S206. Determine whether the high time of the current PWM control period ends. If yes, the AD interrupt is exited; if not, then return to step S502.

S207, exiting the AD sampling and processing the back EMF zero crossing time.

S208, the zero-crossing detection success flag is set, and the free-wheeling end flag is cleared.

S209, setting a delay commutation interrupt TP.

Further, after detecting the zero-crossing of the back EMF, the delay commutation interrupt TP is entered to control the brushless DC motor to perform commutation, as shown in FIG. 8b, and the specific method may include the following steps:

S301. Determine whether the zero-cross detection success flag is set. If yes, step S602 is performed; if not, the delay commutation interrupt TP is exited.

S302, controlling the brushless DC motor to perform a commutation operation.

S303, update the phase.

S304. Clear the zero-crossing detection success flag.

S305, setting to avoid the freewheeling delay interrupt TF.

As shown in FIG. 8c, the back EMF zero-crossing detection method of the brushless DC motor that has not ended in the subsequent flow time of entering the AD interrupt may include the following steps:

S401, setting a freewheeling time end flag.

S402, stopping to avoid the freewheeling delay interrupt TF.

S403, determining whether it is in a high level time of the PWM control period. If yes, go to step S404; if no, exit to avoid the freewheeling delay interrupt TF.

S404, triggering single channel back EMF AD sampling.

S405. Determine whether the current back EMF AD sampling ends. If yes, step S406 is performed; if no, step S405 is continued.

S406, reading the back EMF AD sampling result.

S407, judging whether the back EMF is zero-crossing according to the back-potential AD sampling result. If yes, step S409 is performed. If no, step S408 is performed.

S408. Determine whether the high time of the current PWM control period ends. If yes, the exit avoids the freewheeling delay interrupt TF; if not, then returns to step S404.

S409, exiting the AD sampling and processing the back EMF zero crossing time.

S410, the zero-crossing detection success flag is set, and the free-wheeling end flag is cleared.

S411, setting a delay commutation interrupt TP.

Therefore, in each PWM control period, it can be determined whether the generation of the AD interrupt subsequent stream time is completed according to the context of the freewheeling end time and the time when the AD interrupt is generated, and then the brushless DC motor is passed through the above different manner according to the judgment result. The back-EMF zero-crossing detection is performed to achieve the purpose of avoiding the freewheeling time and performing the back-EMF zero-crossing judgment.

9 is a schematic diagram of the back-EMF zero-crossing detection of a brushless DC motor at an extremely high rotational speed according to an embodiment of the present application. As shown in FIG. 9, in the actual operation of the brushless DC motor, there is one after each commutation. During the freewheeling process, during the freewheeling period, the suspended phase terminal voltage is forcibly pulled to the bus voltage or the power ground, causing some of the back EMF waveform to be annihilated. Therefore, the back EMF sampling during the freewheeling period is invalid, and the freewheeling time is ended. Immediately afterwards, the back electromotive force of the brushless DC motor is continuously sampled multiple times, which can save CPU resources and ensure timely and accurate detection of the back-EMF zero-crossing point, thereby ensuring stable operation of the brushless DC motor at extremely high speed. At the same time, there is no need to add a comparator, which reduces the cost.

The following describes in detail how to multiply the back EMF of the brushless DC motor through the FIFO multi-channel sampling function of the ADC module in the high-level time of the PWM control cycle in conjunction with FIG. 10 to FIG. 12, and according to the sampling after the sampling is completed. As a result, it is judged whether or not the back EMF is zero.

According to an embodiment of the present application, the back potential of the brushless DC motor is multi-sampled by the FIFO multi-channel sampling function of the ADC module during the high-level period of the PWM control period, and the anti-potential is judged according to the sampling result after the sampling is completed. Whether the potential is zero-crossing, including: judging whether to enter the anti-potential zero-crossing detection phase; if yes, obtaining the bus voltage of the brushless DC motor, and configuring the M1 channels of the FIFO as the AD channel corresponding to the current suspended phase terminal voltage, After the configuration is completed, the ADC module continuously samples the M1 channels of the FIFO to sample the back EMF of the brushless DC motor multiple times, wherein M1 is less than or equal to the total number of channels of the FIFO; and the back EMF of the brushless DC motor is performed. After multiple sampling is completed, the sampling result of the M1 channels of the FIFO is obtained, and whether the back EMF is zero-crossed according to the sampling result and the bus voltage is determined; if the back-EM potential crosses zero, the anti-potential zero-crossing detection phase is exited.

According to an embodiment of the present application, if the back EMF does not cross zero, the M2 channels of the FIFO are configured according to the high time of the PWM control period, and the back EMF of the brushless DC motor is continued through the M2 channels of the FIFO. Perform multiple sampling, and judge whether the back EMF is zero-crossing according to the sampling result and the bus voltage after the sampling is completed, where M2 is an integer less than or equal to M1.

According to an embodiment of the present application, the back EMF zero-crossing detection method of the brushless DC motor further includes: determining whether the current time is a high-level start time of the PWM control period; if the current time is a high-level start time of the PWM control period , the bus voltage AD sampling is triggered after the first preset time delay, and enters the back EMF zero-crossing detection stage after the bus voltage AD sampling is completed.

Specifically, referring to FIG. 10, in the process of controlling the brushless DC motor by using the PWM control signal, the counting unit of the PWM can determine whether the current time is the high-level start time of the PWM control period, and if so, Then, the bus voltage AD sampling is triggered after delaying the first preset time (the length of the time is configured by a software program, for example, 4us) (1/2 of the bus voltage is used as the reference voltage for the back-EMF zero-cross detection). Wherein, the bus voltage is set to be sampled after the first preset time to prevent the bus voltage sampling from being inaccurate due to the influence of the power switch. In the first preset time, the duty ratio of the PWM control signal can be compared and judged. If the duty ratio is less than the second preset duty ratio, the conventional back EMF sampling method is used to determine whether the back EMF is zero-crossing, such as After sampling the bus voltage AD, it enters the back-EMF zero-crossing detection stage. At this time, the single-channel of the ADC module is used to sample the suspended phase terminal voltage once, and the sampling result is compared with the bus voltage to determine whether the back-EM potential has passed. Zero; if the duty ratio is greater than the first preset duty cycle, the inverter enters the back-EMF zero-crossing detection phase after the sampling of the bus voltage AD is completed. At this time, the FIFO multi-channel sampling function of the ADC module is opposite to the brushless DC motor. The potential is sampled multiple times, and after the sampling is completed, it is judged whether the back EMF is zero or not according to the sampling result.

Specifically, with continued reference to FIG. 10, an AD interrupt is automatically generated after the bus voltage AD sampling is completed (about 1 us), and the interrupt can be referred to as a first AD interrupt. After entering the first AD interrupt, the AD sampling result of the bus voltage is read, and the 8 channels of the FIFO are configured as the AD channel corresponding to the current suspended phase terminal voltage, and then the first AD interrupt is exited. After the configuration is completed, the ADC module will automatically sample the 8 channels of the configured FIFO continuously, that is, continuously collect the values of the eight suspended phase terminals for a period of sampling time to perform the back EMF of the brushless DC motor. Sampled multiple times. When the ADC module is sampled, the AD interrupt will be generated again. This interrupt can be called the second AD interrupt. After entering the second AD interrupt, the sampling result of the 8 channels of the FIFO is read, that is, the values of the eight suspended phase terminal voltages, and the values of the eight suspended phase terminal voltages are respectively compared with the bus voltage to determine the inverse Whether the potential is zero. If the back EMF crosses zero, the second AD interrupt is exited, and the back EMF zero crossing detection of the current PWM control period ends.

If the back EMF does not cross zero, the number of channels of the FIFO required to detect the back EMF again is determined according to the high time of the current PWM control period (ie, the duty ratio of the PWM control signal) to ensure Collect the back EMF of the brushless DC motor as much as possible during the high-level period of the PWM control cycle. For example, as shown in FIG. 10, according to the high level remaining time of the current PWM control period, it can be determined that M2 (eg, 3) channels are required, then M2 channels are configured as AD channels corresponding to the current suspended phase terminal voltage, and then exit. The second AD interrupt. After the configuration is completed, the ADC module will automatically sample the M2 channels of the configured FIFO continuously, that is, continuously collect the values of the M2 suspended phase terminals for a period of sampling time to perform the back EMF of the brushless DC motor. Sampling again. When the ADC module is sampled, the AD interrupt will be generated again. This interrupt can be called the third AD interrupt. After entering the third AD interrupt, the sampling result of the M2 channels of the FIFO is read, that is, the value of the M2 suspended phase terminal voltages, and the values of the M2 suspended phase terminal voltages are respectively compared with the bus voltages to determine the inverse Whether the potential crosses zero or not, the back-zero detection phase of the current PWM control period ends. The above process is repeated at the beginning of the next PWM control cycle.

As shown in FIG. 11, the back EMF zero-crossing detection method of the brushless DC motor may include the following steps:

S501. Determine whether the current AD interrupt is currently in use. If yes, go to step S502; if no, go to step S503.

S502, reading the bus voltage AD sampling result, and configuring 8-channel FIFO AD sampling to prepare for entering the second interrupt.

S503, determining whether it is in the second AD interrupt. If yes, go to step S504; if no, go to step S508.

S504, reading the 8-channel FIFO AD sampling result.

S505: Determine whether the back EMF is zero-crossing according to the 8-channel FIFO AD sampling result. If yes, go to step S506; if no, go to step S507.

S506, ready to enter the first AD interrupt to perform zero-crossing detection for the back EMF in the next PWM control period.

S507, according to the current PWM duty cycle, configure the corresponding M2 channel FIFO AD sampling to prepare for entering the third AD interrupt. Where M2 is an integer less than or equal to 8.

S508. Determine whether the third AD interrupt is currently in use. If yes, go to step S509; if no, exit the current AD interrupt.

S509, reading the M2 channel FIFO AD sampling result, and judging whether the back EMF is zero-crossing according to the sampling result.

12 is a schematic diagram of the back-EMF zero-crossing detection of a brushless DC motor at an extremely high rotational speed according to an embodiment of the present application. As shown in FIG. 12, the FIFO multi-channel sampling function of the ADC module is used to realize a high voltage in a PWM control period. The back EMF of the brushless DC motor is continuously collected multiple times in a normal time, and the zero-crossing point of the back EMF can be detected accurately and timely, thereby ensuring that the brushless DC motor can stably operate at a very high speed without an external comparator. Reduced costs.

It should be noted that, in the above embodiment, the value of M1 is 8, and in practical applications, M1 can be set to any of the FIFO depths of 4, 5, 6, 7, and 8, so that the actual PWM control can be performed. The duty cycle of the signal triggers the back EMF sampling interrupt multiple times within one PWM control period. For example, the value of M1 can be 4, so that it can be triggered once more than the above specific example, so that the back electromotive force of the brushless DC motor Zero-crossing detection is more timely and accurate.

The following describes in detail how to trigger the ADC single channel to multi-sample the back EMF of the brushless DC motor by hardware trigger mode in the PWM control cycle, and determine the back EMF according to the sampling result after each sampling is completed. Whether the zero crossing is performed, and the bus current of the brushless DC motor is obtained at the middle of the high level of the PWM control cycle. The PWM control signal is a centrally symmetric PWM control signal, that is, the brushless DC motor is controlled by a centrally symmetric PWM control signal during each PWM control period.

According to an embodiment of the present application, in the process of sampling the back electromotive force of the brushless DC motor every predetermined time interval, it is also determined whether the current time is a high-level intermediate time of the PWM control period, and if so, stopping The back EMF of the brushless DC motor is sampled and the bus current ADC sampling is triggered to obtain the bus current of the brushless DC motor.

Specifically, as shown in FIG. 13, the waveform of the bus current is substantially linearly rising during the high level period of each PWM control period, and therefore the instantaneous value of the bus current corresponding to the high-level intermediate time of each PWM control period. Can be approximated as the average of the bus current. In order to facilitate accurate sampling of the average value of the bus current, the constant power control of the brushless DC motor is realized, and the central symmetric PWM control signal is used to control the brushless DC motor in each PWM control period, and is preset every time. Time interval During the sampling of the back EMF of the brushless DC motor, it is judged whether the current time is the high intermediate time of the PWM control period (or within a period of time from the intermediate time), and if so, the bus current ADC is triggered. Sampling to obtain the bus current of the brushless DC motor.

According to an embodiment of the present application, the back EMF zero-crossing detection method of the brushless DC motor further includes: determining whether the current time is the start time of the PWM control period, and if so, triggering the bus voltage ADC sampling to obtain the brushless DC The bus voltage of the motor and the single channel of the ADC are configured to sample the back EMF of the brushless DC motor at a preset time interval of the ADC single channel. After the configuration is completed, the ADC single channel starts at every preset time interval. Brushing the back electromotive force of the DC motor for sampling, and judging whether the back EMF is zero or not according to the sampling result and the bus voltage, and judging whether the sampling frequency of the back EMF is greater than or equal to the first preset number, wherein the first preset number is according to the PWM control period And obtaining the preset time interval; if the sampling time of the back electromotive force is greater than or equal to the first preset number of times, determining that the current time is a high level intermediate time of the PWM control period.

According to an embodiment of the present application, after obtaining the bus current of the brushless DC motor, the single channel of the ADC is also configured to sample the back electromotive force of the brushless DC motor at a preset time interval of the ADC single channel; After that, the ADC single channel starts to sample the back EMF of the brushless DC motor every preset time interval, and judges whether the back EMF is zero-crossing according to the sampling result and the bus voltage until it is judged that the back EMF crosses zero or enters the next PWM control cycle. .

Specifically, referring to FIG. 13, the counting unit of the PWM can determine whether the current time is the start time of the PWM control period, and if so, a PWM interrupt is generated, that is, at the beginning of each PWM cycle. A PWM interrupt. In this interrupt, the bus voltage ADC sampling can be triggered to obtain the bus voltage of the brushless DC motor, and the ADC single channel is configured to make the ADC single channel reverse the brushless DC motor every preset time interval (such as TWus). The potential is sampled and the number of times the ADC interrupt is generated is cleared, then the PWM interrupt is exited. After the configuration is completed, the ADC interrupt will be generated every preset time interval. During the ADC interrupt process, the back EMF of the brushless DC motor is sampled, and the sampling result is read, and the back EMF is judged to be zero-crossed according to the sampling result and the bus voltage, and the number of ADC interruptions is accumulated, and the number of ADC interruptions When the first preset number is greater than or equal to, the current time is determined as the high-level intermediate time of the PWM control period (or within a period of time from the intermediate time), and the back-EM ADC sampling result is read at this time, and according to the sampling result and The bus voltage determines whether the back EMF is zero-crossing, and simultaneously triggers the bus current ADC sampling to obtain the bus current of the brushless DC motor.

It should be noted that, under certain conditions (for example, the PWM interrupt time is small and negligible), the first preset number in the above embodiment may be N/2, where N is a PWM control period (such as Tus). ) The ratio of the preset time interval (such as TWus), when the number of ADC interrupts is greater than or equal to T/2TW, it can be judged that the current time is the high-level intermediate time of the PWM control period (or within a period of time from the intermediate time) . That is to say, when setting the first preset number, the PWM control period, the preset time interval, the PWM interrupt time and the bus current acquisition time can be combined to make a reasonable setting to ensure that the bus current is sampled as much as possible in the PWM. The high-frequency intermediate time of the control cycle or nearby makes the sampling of the bus current more accurate and ensures the constant power control of the brushless DC motor.

Further, after obtaining the bus current of the brushless DC motor, the single channel of the ADC is configured to continue sampling the back electromotive force of the brushless DC motor every predetermined time interval of the ADC, and according to the sampling result and the bus bar. The voltage determines whether the back EMF has crossed zero until it is judged that the back EMF has crossed zero or entered the next PWM control period. The above operation is repeated in the next PWM control cycle.

Further, as shown in FIG. 14a, the back EMF zero-crossing detection method of the brushless DC motor may include the following steps:

S601, triggers the bus voltage ADC sampling and clears the number of ADC interrupts.

S602. Determine whether the bus voltage ADC sampling ends. If yes, step S603 is performed; if no, step S602 is continued.

S603, reading the bus voltage ADC sampling result, and configuring the single channel sampling of the back EMF ADC every TWus trigger.

Further, after the configuration is completed, as shown in FIG. 14b, the back EMF zero-crossing detection method of the brushless DC motor may include the following steps:

S701, reading the back-EM ADC sampling result, and determining whether the back-EM potential is zero-crossing according to the sampling result and the bus voltage, and adding 1 to the number of ADC interruptions.

S702. Determine whether the current number of ADC interrupts is equal to N/2. If yes, go to step S703; if no, exit the current ADC interrupt.

S703, triggering bus current ADC sampling.

S704, determining whether the bus current ADC sampling ends. If yes, step S705 is performed; if no, step S704 is continued.

S705, reading the bus current ADC sampling result, and configuring a single channel sampling of the back EMF ADC every TWus trigger.

Therefore, by adopting continuous hardware triggering back-EMF ADC sampling mode, the back-EM potential can be collected multiple times in one PWM cycle, which can not only detect the zero-crossing zero point in time and accurately, and ensure the stable operation of the brushless DC motor at extremely high speed. At the same time, it can take into account the accurate sampling of the average value of the bus current, realize the constant power control of the brushless DC motor, and this scheme does not need to add a comparator, which reduces the cost.

In summary, according to the back EMF zero-crossing detection method of the brushless DC motor according to the embodiment of the present application, in the process of controlling the brushless DC motor, the PWM control signal of the brushless DC motor is obtained in each PWM control period. The duty cycle, and determine whether the duty cycle is greater than the first preset duty cycle, if the duty cycle is greater than the first preset duty cycle, then pass through the single channel of the ADC module during the high level of the PWM control cycle The back EMF of the brushless DC motor is continuously sampled multiple times, and the back EMF is judged to be zero-crossed according to the previous sampling result during the sampling process, or the FIFO multi-channel of the ADC module is passed during the high-level time of the PWM control period. The sampling function samples the back electromotive force of the brushless DC motor multiple times, and judges whether the back EMF is zero-crossing according to the sampling result after the sampling is completed, or triggers the ADC single channel every preset time interval by the hardware trigger mode in the PWM control period. The back EMF of the brushless DC motor is sampled, and after each sampling is completed, it is judged whether the back EMF is zero-crossing according to the sampling result, wherein the PWM control signal is center-symmetrical PWM control signal. Therefore, not only can the zero-crossing point of the back EMF be detected in time and accurately, the motor can be stably operated at a very high speed, and the comparator can be added without further increase of cost.

15 is a flow chart of a method for detecting a back-EMF zero-crossing of another brushless DC motor according to an embodiment of the present application. As shown in FIG. 15, the method for detecting the back-EMF zero-crossing of another brushless DC motor according to the embodiment of the present application may include the following steps:

S801, in the process of controlling the brushless DC motor, acquiring the duty ratio of the PWM control signal of the brushless DC motor in each PWM control period, and determining whether the duty ratio is greater than the first preset duty ratio.

S802, if the duty ratio is greater than the first preset duty ratio, the back potential of the brushless DC motor is continuously sampled multiple times through the single channel of the ADC module during the high level of the PWM control period, and is sampled In the process, it is judged whether the back EMF is zero or not based on the result of the previous sampling.

Among them, how to continuously sample the back EMF of the brushless DC motor through the single channel of the ADC module during the high level of the PWM control period, and judge whether the back EMF is zero or zero according to the previous sampling result during the sampling process. It has been described in detail in the above embodiments. For the specific process, refer to the foregoing embodiment. To avoid redundancy, no further details are provided herein.

According to the anti-potential zero-crossing detecting method of the brushless DC motor according to the embodiment of the present application, in the process of controlling the brushless DC motor, the duty ratio of the PWM control signal of the brushless DC motor is obtained in each PWM control period, And determining whether the duty ratio is greater than the first preset duty ratio, and if the duty ratio is greater than the first preset duty ratio, passing through the single channel of the ADC module to the brushless DC motor during the high level of the PWM control period The back EMF is sampled continuously for multiple times, and during the sampling process, it is judged whether the back EMF is zero or not based on the previous sampling result.

In addition, embodiments of the present application also provide a non-transitory computer readable storage medium having stored thereon a computer program that, when executed by the processor, implements the back EMF zero crossing detection method of the brushless DC motor described above.

According to the non-transitory computer readable storage medium of the embodiment of the present application, by performing the above-described back-EMF zero-crossing detection method of the brushless DC motor, not only the back-zero crossing point can be detected in time and accurately, but also the motor is stably operated at the pole. High speed and no additional comparators can reduce costs.

16 is a block schematic diagram of a back EMF zero crossing detecting device of a brushless DC motor according to an embodiment of the present application. As shown in FIG. 16, the back EMF zero-crossing detecting device of the brushless DC motor of the embodiment of the present application includes: an obtaining unit 100, a confirming unit 200, and a sampling unit 300.

The obtaining unit 100 is configured to acquire a duty ratio of a PWM control signal of the brushless DC motor in each PWM control period in the process of controlling the brushless DC motor; the confirming unit 200 is configured to determine whether the duty ratio is greater than a first preset duty ratio; the sampling unit 300 is configured to perform any one of the following operations when the duty ratio is greater than the first preset duty ratio: passing the ADC module in a high level time of the PWM control period The single channel continuously samples the back EMF of the brushless DC motor continuously, and judges whether the back EMF is zero or zero according to the previous sampling result during the sampling process; the FIFO of the ADC module is more than the high level of the PWM control period. The channel sampling function samples the back electromotive force of the brushless DC motor multiple times, and judges whether the back EMF is zero-crossing according to the sampling result after the sampling is completed; triggers the ADC single channel every preset time interval by the hardware trigger mode in the PWM control period. The back EMF of the brushless DC motor is sampled, and after each sampling is completed, it is judged whether the back EMF is zero-crossing according to the sampling result, wherein the PWM control signal is center-symmetrical PWM control signal.

According to an embodiment of the present application, the sampling unit 300 is further configured to determine whether the freewheeling time of the brushless DC motor ends after a high level time of the PWM control period, and pass the ADC module after the freewheeling time ends. The single channel continuously samples the back EMF of the brushless DC motor continuously, and determines whether the back EMF is zero or zero according to the previous sampling result during the sampling process.

It should be noted that, for details not disclosed in the back-EMF zero-crossing detecting device of the brushless DC motor of the embodiment of the present application, refer to the details disclosed in the back-EMF zero-crossing detecting method of the brushless DC motor according to the embodiment of the present application. , specifically no longer detailed here.

According to the anti-potential zero-crossing detecting device of the brushless DC motor according to the embodiment of the present application, the PWM control signal of the brushless DC motor is obtained in each PWM control cycle by the acquiring unit in the process of controlling the brushless DC motor. The ratio is determined by the confirmation unit to determine whether the duty ratio is greater than the first preset duty ratio, and when the duty ratio is greater than the first preset duty ratio by the sampling unit, passing in the high level time of the PWM control period The single channel of the ADC module continuously samples the back EMF of the brushless DC motor continuously, and judges whether the back EMF is zero-crossing according to the previous sampling result during the sampling process, or passes the ADC during the high-level time of the PWM control cycle. The FIFO multi-channel sampling function of the module samples the back EMF of the brushless DC motor multiple times, and judges whether the back EMF is zero-crossing according to the sampling result after the sampling is completed, or triggers the ADC single channel per hardware trigger mode in the PWM control period. The back EMF of the brushless DC motor is sampled at a preset time interval, and after each sampling is completed, it is judged whether the back EMF is zero or not according to the sampling result. The PWM control signal is a centrally symmetric PWM control signal. Therefore, not only can the zero-crossing point of the back EMF be detected in time and accurately, the motor can be stably operated at a very high speed, and the comparator can be added without further increase of cost.

In addition, the embodiment of the present application also proposes a control system for a brushless DC motor, which includes the back EMF zero crossing detecting device of the above brushless DC motor.

According to the control system of the brushless DC motor according to the embodiment of the present application, the back EMF zero-crossing detecting device of the brushless DC motor described above can not only detect the zero-crossing point of the back EMF in a timely and accurate manner, but also ensure that the motor runs stably at a very high speed. And without the need to add additional comparators, you can reduce costs.

Furthermore, embodiments of the present application also propose a vacuum cleaner comprising the above described control system for a brushless DC motor.

According to the vacuum cleaner of the embodiment of the present application, the control system of the brushless DC motor can not only detect the zero-crossing point of the back EMF in time and accurately, but also ensure that the motor runs stably at a very high speed, and the comparator can be reduced without additional amplifier. cost.

It should be understood that portions of the application can be implemented in hardware, software, firmware, or a combination thereof. In the above-described embodiments, multiple steps or methods may be implemented in software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented in hardware, as in another embodiment, it can be implemented by any one or combination of the following techniques well known in the art: having logic gates for implementing logic functions on data signals. Discrete logic circuits, application specific integrated circuits with suitable combinational logic gates, programmable gate arrays (PGAs), field programmable gate arrays (FPGAs), etc.

In addition, in the description of the present application, the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "upper", "lower", "front", "rear", "Left", "Right", "Vertical", "Horizontal", "Top", "Bottom", "Inside", "Outside", "Clockwise", "Counterclockwise", "Axial", "Radial" The orientation or positional relationship of the indications, the "circumferential" and the like is based on the orientation or positional relationship shown in the drawings, and is merely for convenience of description of the present application and simplified description, and does not indicate or imply that the device or component referred to must have a specific The orientation, construction and operation in a particular orientation are not to be construed as limiting the invention.

Moreover, the terms "first" and "second" are used for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, features defining "first" or "second" may include at least one of the features, either explicitly or implicitly. In the description of the present application, the meaning of "a plurality" is at least two, such as two, three, etc., unless specifically defined otherwise.

In the present application, the terms "installation", "connected", "connected", "fixed" and the like shall be understood broadly, and may be either a fixed connection or a detachable connection, unless otherwise explicitly stated and defined. , or integrated; can be mechanical or electrical connection; can be directly connected, or indirectly connected through an intermediate medium, can be the internal communication of two elements or the interaction of two elements, unless otherwise specified Limited. For those skilled in the art, the specific meanings of the above terms in the present application can be understood on a case-by-case basis.

In the present application, the first feature "on" or "below" the second feature may be the direct contact of the first and second features, or the first and second features are indirectly through the intermediate medium, unless otherwise explicitly stated and defined. contact. Moreover, the first feature "above", "above" and "above" the second feature may be that the first feature is directly above or above the second feature, or only that the first feature level is higher than the second feature. The first feature "below", "below" and "below" the second feature may be that the first feature is directly below or obliquely below the second feature, or merely that the first feature level is less than the second feature.

In the description of the present specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" and the like means a specific feature described in connection with the embodiment or example. A structure, material or feature is included in at least one embodiment or example of the application. In the present specification, the schematic representation of the above terms is not necessarily directed to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. In addition, various embodiments or examples described in the specification, as well as features of various embodiments or examples, may be combined and combined.

While the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are illustrative and are not to be construed as limiting the scope of the present application. The embodiments are subject to variations, modifications, substitutions and variations.

Claims (17)

  1. A method for detecting a zero-crossing zero-crossing of a brushless DC motor, comprising the steps of:
    Obtaining a duty ratio of a PWM control signal of the brushless DC motor during each PWM control period;
    Detecting and confirming that the duty ratio is greater than the first preset duty ratio, performing any of the following operations:
    Performing a plurality of consecutive times of back electromotive force of the brushless DC motor through a single channel of the ADC module during a high level period of the PWM control period, and performing the back EMF according to a previous sampling result during sampling Perform zero-crossing detection;
    Performing a multiple sampling of the back EMF of the brushless DC motor through a FIFO multi-channel sampling function of the ADC module during a high level period of the PWM control period, and performing the back EMF according to the sampling result after the sampling is completed. Zero crossing detection;
    During the PWM control period, the ADC single channel is triggered by the hardware trigger mode to sample the back EMF of the brushless DC motor every preset time interval, and the back EMF is performed according to the sampling result after each sampling is completed. Zero crossing detection, wherein the PWM control signal is a centrally symmetric PWM control signal.
  2. A method of detecting a zero-potential zero-crossing of a brushless DC motor according to claim 1, wherein during said high-level period of said PWM control period, detecting and confirming completion of said freewheeling time of said brushless DC motor The back EMF of the brushless DC motor is continuously sampled multiple times through a single channel of the ADC module, and the back EMF is subjected to zero-crossing detection according to the last sampling result during the sampling process.
  3. The method of detecting a zero-potential zero-crossing of a brushless DC motor according to claim 1 or 2, wherein said brushless passing through said single channel of said ADC module during said high-level period of said PWM control period The back electromotive force of the DC motor is continuously sampled multiple times, and during the sampling process, the back EMF is subjected to zero-crossing detection according to the previous sampling result, including:
    Detecting and confirming that the brushless DC motor enters a back-EMF zero-crossing detection stage, acquiring a bus voltage of the brushless DC motor, and configuring a single channel of the ADC module as an AD channel corresponding to a current suspended phase terminal voltage, and Triducing a back channel of the ADC module to perform a first sampling of a back EMF of the brushless DC motor;
    After the first sampling is completed, the first sampling result is obtained, and the single channel of the ADC module is triggered to perform the second sampling of the back electromotive force of the brushless DC motor, and the second sampling process is performed according to the second sampling process. Performing a zero-crossing detection of the back EMF by the first sampling result and the bus voltage;
    The back EMF is detected and confirmed to be zero crossing, and the back EMF zero crossing detection phase is exited.
  4. The method of detecting a zero-crossing zero-crossing of a brushless DC motor according to claim 3, wherein detecting and confirming that the back EMF has not passed zero, acquiring the current sampling result after the current sampling is completed, and triggering the a single channel of the ADC module performs a next sampling of the back EMF of the brushless DC motor, and performs zero-crossing detection of the back EMF according to the current sampling result and the bus voltage during the next sub-sampling And exiting the back-EMF zero-crossing detection phase until it is confirmed that the back-EMF zero-crossing or the number of sampling times is greater than or equal to a preset number of times.
  5. The method of detecting a zero-potential zero-crossing of a brushless DC motor according to claim 1, wherein said FIFO multi-channel sampling function of said ADC module during said high-level period of said PWM control period The back electromotive force of the brush DC motor is sampled multiple times, and after the sampling is completed, the back EMF is subjected to zero-crossing detection according to the sampling result, including:
    Detecting and confirming that the brushless DC motor enters the back EMF zero-crossing detection stage, acquiring the bus voltage of the brushless DC motor, and configuring the M1 channels of the FIFO as the AD channel corresponding to the current suspended phase terminal voltage, After the configuration is completed, the ADC module continuously samples the M1 channels of the FIFO to perform multiple sampling on the back electromotive force of the brushless DC motor, wherein M1 is less than or equal to the total channel number of the FIFO;
    After performing multiple sampling on the back potential of the brushless DC motor, acquiring sampling results of the M1 channels of the FIFO, and performing zero-crossing detection on the back EMF according to the sampling result and the bus voltage;
    The back EMF is detected and confirmed to be zero crossing, and the back EMF zero crossing detection phase is exited.
  6. A method of detecting a zero-potential zero-crossing of a brushless DC motor according to claim 5, wherein detecting and confirming that said back EMF has not passed zero, said FIFO according to a high level of said PWM control period M2 channels are configured, and the back EMF of the brushless DC motor is continuously sampled multiple times through the M2 channels of the FIFO, and after the sampling is completed, the back EMF is performed according to the sampling result and the bus voltage Zero crossing detection, where M2 is an integer less than or equal to M1.
  7. The method of detecting a zero-crossing zero-crossing of a brushless DC motor according to claim 3 or 5, further comprising:
    Detecting and confirming that the current time is a high-level start time of the PWM control period, triggering a bus voltage AD sampling after a delay of a first preset time, and entering the back-EM potential after the bus voltage AD sampling is completed. Zero detection phase.
  8. A method of detecting a zero-potential zero-crossing of a brushless DC motor according to claim 1, wherein during the sampling of the back electromotive force of said brushless DC motor every predetermined time interval, detecting and confirming the current The time is the middle of the high level of the PWM control period, stopping sampling the back EMF of the brushless DC motor, and triggering the bus current ADC sampling to obtain the bus current of the brushless DC motor.
  9. The method of detecting a zero-crossing zero-crossing of a brushless DC motor according to claim 8, further comprising:
    Detecting and confirming that the current time is the start time of the PWM control period, triggering bus voltage ADC sampling to obtain a bus voltage of the brushless DC motor, and configuring the ADC single channel to make the ADC single channel every Sampling the back EMF of the brushless DC motor at a preset time interval;
    After the configuration is completed, the ADC single channel starts to sample the back EMF of the brushless DC motor every preset time interval, and performs zero-crossing detection on the back EMF according to the sampling result and the bus voltage, and simultaneously detects The number of times of the back EMF;
    Detecting and confirming that the number of times of sampling of the back EMF is greater than or equal to the first preset number of times, and confirming that the current time is a high level intermediate time of the PWM control period, wherein the first preset number of times is according to the PWM control period and The second preset time is acquired.
  10. A method of detecting a zero-crossing zero-crossing of a brushless DC motor according to claim 9, wherein after obtaining a bus current of said brushless DC motor, said ADC single channel is further configured to cause said ADC Sampling the back EMF of the brushless DC motor every second predetermined time;
    After the configuration is completed, the ADC single channel starts to sample the back EMF of the brushless DC motor every preset time interval, and performs zero-crossing detection on the back EMF according to the sampling result and the bus voltage until confirmation The back EMF crosses zero or enters the next PWM control cycle.
  11. The method of detecting a zero-potential zero-crossing of a brushless DC motor according to any one of claims 1 to 10, wherein detecting and confirming that the duty ratio is smaller than a second preset duty ratio, in the PWM The back EMF of the brushless DC motor is sampled once by a conventional back EMF sampling method during a high period of the control period, and the back EMF is subjected to zero crossing detection according to the sampling result, wherein the second preset The duty cycle is less than the first predetermined duty cycle.
  12. A method for detecting a zero-crossing zero-crossing of a brushless DC motor, comprising the steps of:
    Obtaining a duty ratio of a PWM control signal of the brushless DC motor during each PWM control period;
    Detecting and confirming that the duty ratio is greater than the first preset duty ratio, continuously performing a back EMF of the brushless DC motor through a single channel of the ADC module during a high level period of the PWM control period Subsampling, and zero-crossing detection of the back EMF according to the last sampling result during the sampling process.
  13. A non-transitory computer readable storage medium having stored thereon a computer program, wherein the program is executed by a processor to implement a back electromotive force of a brushless DC motor according to any one of claims 1-11 A zero-crossing detection method, or a method of detecting a zero-crossing zero-crossing of a brushless DC motor according to claim 12.
  14. A back EMF zero-crossing detecting device for a brushless DC motor, comprising:
    An acquiring unit, configured to acquire a duty ratio of a PWM control signal of the brushless DC motor in each PWM control period;
    a confirmation unit, configured to detect and confirm that the duty ratio is greater than the first preset duty ratio;
    a sampling unit, configured to perform any one of the following operations according to the confirmation result of the confirmation unit:
    Performing a plurality of consecutive times of back electromotive force of the brushless DC motor through a single channel of the ADC module during a high level period of the PWM control period, and performing the back EMF according to a previous sampling result during sampling Perform zero-crossing detection;
    Performing a multiple sampling of the back EMF of the brushless DC motor through a FIFO multi-channel sampling function of the ADC module during a high level period of the PWM control period, and performing the back EMF according to the sampling result after the sampling is completed. Zero crossing detection;
    During the PWM control period, the ADC single channel is triggered by the hardware trigger mode to sample the back EMF of the brushless DC motor every preset time interval, and the back EMF is performed according to the sampling result after each sampling is completed. Zero crossing detection, wherein the PWM control signal is a centrally symmetric PWM control signal.
  15. A back EMF zero-crossing detecting device for a brushless DC motor according to claim 14, wherein said sampling unit is further configured to detect and confirm said none during a high level time of said PWM control period The freewheeling time of the brush DC motor ends, the back potential of the brushless DC motor is continuously sampled multiple times through a single channel of the ADC module, and the back EMF is zero-crossed according to the previous sampling result during the sampling process. Detection.
  16. A control system for a brushless DC motor, comprising the anti-potential zero-crossing detecting device of the brushless DC motor according to claim 14 or 15.
  17. A vacuum cleaner comprising the control system of the brushless DC motor of claim 16.
PCT/CN2019/080423 2018-03-30 2019-03-29 Vacuum cleaner, and counter electromotive force zero-cross detection method, apparatus and control system of motor WO2019185018A1 (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
CN201810296965.8 2018-03-30
CN201810296820.8 2018-03-30
CN201810294383.6A CN108631658A (en) 2018-03-30 2018-03-30 The back-emf zero passage detection method, apparatus and control system of dust catcher, motor
CN201810295559.X 2018-03-30
CN201810294383.6 2018-03-30
CN201810296965.8A CN108448954A (en) 2018-03-30 2018-03-30 The back-emf zero passage detection method, apparatus and control system of dust catcher, motor
CN201810295559.XA CN108606724A (en) 2018-03-30 2018-03-30 The back-emf zero passage detection method, apparatus and control system of dust catcher, motor
CN201810296820.8A CN108448953B (en) 2018-03-30 2018-03-30 Counter potential zero-crossing detection method, device and control system for dust collector and motor

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Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7301298B2 (en) * 2005-01-07 2007-11-27 Stmicroelectronics, Inc. Back EMF detection circuit and method for a sensorless brushless DC (BLDC) motor
CN103018541A (en) * 2012-11-06 2013-04-03 中南林业科技大学 Counter-potential zero-crossing detection circuit and counter-potential zero-crossing detection method for brushless direct-current motor
CN105227012A (en) * 2015-11-03 2016-01-06 西北工业大学 Back-emf zero passage detection method under the two chopper control mode of brshless DC motor
CN108448954A (en) * 2018-03-30 2018-08-24 江苏美的清洁电器股份有限公司 The back-emf zero passage detection method, apparatus and control system of dust catcher, motor
CN108448953A (en) * 2018-03-30 2018-08-24 江苏美的清洁电器股份有限公司 The back-emf zero passage detection method, apparatus and control system of dust catcher, motor
CN108606724A (en) * 2018-03-30 2018-10-02 江苏美的清洁电器股份有限公司 The back-emf zero passage detection method, apparatus and control system of dust catcher, motor
CN108631658A (en) * 2018-03-30 2018-10-09 江苏美的清洁电器股份有限公司 The back-emf zero passage detection method, apparatus and control system of dust catcher, motor

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7301298B2 (en) * 2005-01-07 2007-11-27 Stmicroelectronics, Inc. Back EMF detection circuit and method for a sensorless brushless DC (BLDC) motor
CN103018541A (en) * 2012-11-06 2013-04-03 中南林业科技大学 Counter-potential zero-crossing detection circuit and counter-potential zero-crossing detection method for brushless direct-current motor
CN105227012A (en) * 2015-11-03 2016-01-06 西北工业大学 Back-emf zero passage detection method under the two chopper control mode of brshless DC motor
CN108448954A (en) * 2018-03-30 2018-08-24 江苏美的清洁电器股份有限公司 The back-emf zero passage detection method, apparatus and control system of dust catcher, motor
CN108448953A (en) * 2018-03-30 2018-08-24 江苏美的清洁电器股份有限公司 The back-emf zero passage detection method, apparatus and control system of dust catcher, motor
CN108606724A (en) * 2018-03-30 2018-10-02 江苏美的清洁电器股份有限公司 The back-emf zero passage detection method, apparatus and control system of dust catcher, motor
CN108631658A (en) * 2018-03-30 2018-10-09 江苏美的清洁电器股份有限公司 The back-emf zero passage detection method, apparatus and control system of dust catcher, motor

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