WO2019185018A1

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

Info

Publication number: WO2019185018A1
Application number: PCT/CN2019/080423
Authority: WO
Inventors: 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
Priority date: 2018-03-30
Filing date: 2019-03-29
Publication date: 2019-10-03

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

吸尘器、电机的反电势过零检测方法、装置和控制***Method, device and control system for detecting back-force zero-crossing of vacuum cleaner and motor

相关申请的交叉引用Cross-reference to related applications

本申请基于申请号为201810295559.X、201810294383.6、201810296820.8和201810296965.8，申请日为2018年03月30日的中国专利申请提出，并要求该中国专利申请的优先权，该中国专利申请的全部内容在此引入本申请作为参考。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.

技术领域Technical field

本发明涉及电机控制技术领域，特别涉及一种无刷直流电机的反电势过零检测方法、一种无刷直流电机的反电势过零检测装置、一种无刷直流电机的控制***和一种吸尘器。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.

背景技术Background technique

目前，在无刷直流电机无传感器驱动控制技术领域中，电机的转子位置检测方法有多种，其中以反电势过零法简单、有效而被广泛应用。反电势过零法的基本原理是当无刷直流电机的某相绕组的反电势过零时，转子直轴与该相绕组轴线恰好重合，因此只要判断出各相绕组的反电势过零点就可获知电机的转子位置。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.

相关技术中，反电势过零检测的方法有两种：一、采用ADC(Analog-to-Digital Converter，模/数转换器)模块在每个PWM(Pulse Width Modulation，脉冲宽度调制)控制周期采样一次无刷直流电机悬空相的端电压，然后将采样结果与参考电压进行比较判断是否发生过零；二、增加外部比较器，利用硬件比较无刷直流电机悬空相的端电压与参考电压的大小关系，实现反电势过零检测。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.

然而，上述检测方法存在以下缺点：1)当采用方法一进行反电势过零检测时，检测到的反电势过零时刻均滞后实际反电势过零时刻约为一个PWM周期，在无刷直流电机的转速较低，PWM控制信号的占空比较小时，一个换相间隔内有多个PWM周期，滞后一个PWM周期对无刷直流电机换相的影响较小，但是，当无刷直流电机的转速较高时，一个换相间隔内的PWM周期的个数较少，反电势过零检测滞后可能会导致无刷直流电机换相滞后，从而影响无刷直流电机的稳定性；2)采用方法二进行反电势过零检测时，由于增加了外部比较器，因此会导致成本较高。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.

发明内容Summary of the invention

本申请旨在至少在一定程度上解决相关技术中的技术问题之一。为此，本申请的第一个目的在于提出一种无刷直流电机的反电势过零检测方法，不仅能够及时、准确地检测到反电势过零点，保证电机稳定运行在极高转速，而且无需额外增加比较器，能够降低成本。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.

本申请的第二个目的在于提出另一种无刷直流电机的反电势过零检测方法。A second object of the present application is to provide a method for detecting a back-EMF zero-crossing of another brushless DC motor.

本申请的第三个目的在于提出一种非临时性计算机可读存储介质。A third object of the present application is to propose a non-transitory computer readable storage medium.

本申请的第四个目的在于提出一种无刷直流电机的反电势过零检测装置。A fourth object of the present application is to provide a back EMF zero crossing detecting device for a brushless DC motor.

本申请的第五个目的在于提出一种无刷直流电机的控制***。A fifth object of the present application is to provide a control system for a brushless DC motor.

本申请的第六个目的在于提出一种吸尘器。A sixth object of the present application is to provide a vacuum cleaner.

为实现上述目的，本申请第一方面实施例提出了一种无刷直流电机的反电势过零检测方法，包括以下步骤：在每个PWM控制周期内获取所述无刷直流电机的PWM控制信号的占空比；检测并确认所述占空比大于所述第一预设占空比，执行如下操作中的任意一种：在所述PWM控制周期的高电平时间内通过ADC模块的单通道对所述无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果对所述反电势进行过零检测；在所述PWM控制周期的高电平时间内通过ADC模块的FIFO多通道采样功能对所述无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果对所述反电势进行过零检测；在所述PWM控制周期内通过硬件触发方式触发ADC单通道每隔预设时间间隔对所述无刷直流电机的反电势进行采样，并在每次采样完成后根据采样结果对所述反电势进行过零检测，其中，所述PWM控制信号为中心对称的PWM控制信号。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.

根据本申请实施例的无刷直流电机的反电势过零检测方法，在每个PWM控制周期内获取无刷直流电机的PWM控制信号的占空比，检测并确认占空比大于第一预设占空比，在PWM控制周期的高电平时间内通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果对反电势进行过零检测，或者在PWM控制周期的高电平时间内通过ADC模块的FIFO多通道采样功能对无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果对反电势进行过零检测，或者在PWM控制周期内通过硬件触发方式触发ADC单通道每隔预设时间间隔对无刷直流电机的反电势进行采样，并在每次采样完成后根据采样结果对反电势进行过零检测，其中，PWM控制信号为中心对称的PWM控制信号。从而不仅能够及时、准确地检测到反电势过零点，保证电机稳定运行在极高转速，而且无需额外增加比较器，能够降低成本。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.

为实现上述目的，本申请第二方面实施例提出了另一种无刷直流电机的反电势过零检测方法，包括以下步骤：在每个PWM控制周期内获取所述无刷直流电机的PWM控制信号的占空比；检测并确认所述占空比大于所述第一预设占空比，在所述PWM控制周期的高电平时间内通过ADC模块的单通道对所述无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果对所述反电势进行过零检测。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.

根据本申请实施例的无刷直流电机的反电势过零检测方法，在每个PWM控制周期内获取无刷直流电机的PWM控制信号的占空比，检测并确定占空比是否大于第一预设占空比，在PWM控制周期的高电平时间内通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果对反电势进行过零检测。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.

为实现上述目的，本申请第三方面实施例提出了一种非临时性计算机可读存储介质，其上存储有计算机程序，该程序被处理器执行时实现上述的无刷直流电机的反电势过零检测方法。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.

根据本申请实施例的非临时性计算机可读存储介质，通过执行上述的无刷直流电机的反电势过零检测方法，不仅能够及时、准确地检测到反电势过零点，保证电机稳定运行在极高转速，而且无需额外增加比较器，能够降低成本。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.

为实现上述目的，本申请第四方面实施例提出的一种无刷直流电机的反电势过零检测装置，包括：获取单元，用于在每个PWM控制周期内获取所述无刷直流电机的PWM控制信号的占空比；确认单元，用于检测并确认所述占空比大于第一预设占空比；采样单元，用于根据所述确认单元的确认结果执行如下操作中的任意一种：在所述PWM控制周期的高电平时间内通过ADC模块的单通道对所述无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果对所述反电势进行过零检测；在所述PWM控制周期的高电平时间内通过ADC模块的FIFO多通道采样功能对所述无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果对所述反电势进行过零检测；在所述PWM控制周期内通过硬件触发方式触发ADC单通道每隔预设时间间隔对所述无刷直流电机的反电势进行采样，并在每次采样完成后根据采样结果对所述反电势进行过零检测，其中，所述PWM控制信号为中心对称的PWM控制信号。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.

根据本申请实施例的无刷直流电机的反电势过零检测装置，通过获取单元在每个PWM控制周期内获取无刷直流电机的PWM控制信号的占空比，并通过确认单元检测并确认占空比大于第一预设占空比，以及通过采样单元根据确认单元的确认结果，在PWM控制周期的高电平时间内通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果对反电势进行过零检测，或者在PWM控制周期的高电平时间内通过ADC模块的FIFO多通道采样功能对无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果对反电势进行过零检测，或者在PWM控制周期内通过硬件触发方式触发ADC单通道每隔预设时间间隔对无刷直流电机的反电势进行采样，并在每次采样完成后根据采样结果对反电势进行过零检测，其中，PWM控制信号为中心对称的PWM控制信号。从而不仅能够及时、准确地检测到反电势过零点，保证电机稳定运行在极高转速，而且无需额外增加比较器，能够降低成本。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.

为实现上述目的，本申请第五方面实施例提出了一种无刷直流电机的控制***，其包括上述的无刷直流电机的反电势过零检测装置。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.

根据本申请实施例的无刷直流电机的控制***，通过上述的无刷直流电机的反电势过零检测装置，不仅能够及时、准确地检测到反电势过零点，保证电机稳定运行在极高转速，而且无需额外增加比较器，能够降低成本。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.

为实现上述目的，本申请第六方面实施例提出了一种吸尘器，其包括上述的无刷直流电机的控制***。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.

根据本申请实施例的吸尘器，通过上述的无刷直流电机的控制***，不仅能够及时、准确地检测到反电势过零点，保证电机稳定运行在极高转速，而且无需额外增加比较器，能够降低成本。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.

附图说明DRAWINGS

图1是根据本申请实施例的无刷直流电机的反电势过零检测方法的流程图；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;

图2a是A相一个周期的端电压波形图；Figure 2a is a terminal voltage waveform diagram of one cycle of phase A;

图2b是A相悬空阶段的端电压波形图；Figure 2b is a waveform diagram of the terminal voltage of the phase A suspension phase;

图3是相关技术中无刷直流电机的反电势过零检测的示意图；3 is a schematic diagram of a back-EMF zero-crossing detection of a brushless DC motor in the related art;

图4是根据本申请第一方面实施例的无刷直流电机的反电势过零检测的示意图；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;

图5是根据本申请第一方面具体实施例的无刷直流电机的反电势过零检测方法的流程图；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;

图6是根据本申请一个实施例的极高转速下无刷直流电机的反电势过零检测的示意图；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;

图7a是根据本申请第二方面实施例的无刷直流电机的反电势过零检测的示意图；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;

图7b是根据本申请第三方面实施例的无刷直流电机的反电势过零检测的示意图；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;

图8a-图8c是根据本申请第二方面具体实施例的无刷直流电机的反电势过零检测方法的流程图；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;

图9是根据本申请另一个实施例的极高转速下无刷直流电机的反电势过零检测的示意图；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;

图10是根据本申请第四方面实施例的无刷直流电机的反电势过零检测的示意图；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;

图11是根据本申请第三方面具体实施例的无刷直流电机的反电势过零检测方法的流程图；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;

图12是根据本申请又一个实施例的极高转速下无刷直流电机的反电势过零检测的示意图；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;

图13是根据本申请第五方面实施例的无刷直流电机的反电势过零检测的示意图；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;

图14a是根据本申请第四方面具体实施例的无刷直流电机的反电势过零检测方法的流程图；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;

图14b是根据本申请第五方面具体实施例的无刷直流电机的反电势过零检测方法的流程图；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;

图15是根据本申请实施例的另一种无刷直流电机的反电势过零检测方法的流程图；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;

图16是根据本申请实施例的无刷直流电机的反电势过零检测装置的方框示意图。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.

具体实施方式detailed description

下面详细描述本申请的实施例，所述实施例的示例在附图中示出，其中自始至终相同或类似的标号表示相同或类似的元件或具有相同或类似功能的元件。下面通过参考附图描述的实施例是示例性的，旨在用于解释本申请，而不能理解为对本申请的限制。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.

下面参考附图来描述根据本申请实施例提出的无刷直流电机的反电势过零检测方法、非临时性计算机可读存储介质、无刷直流电机的反电势过零检测装置、无刷直流电机的控制***以及吸尘器。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.

图1是根据本申请实施例的无刷直流电机的反电势过零检测方法的流程图。如图1所示，本申请实施例的无刷直流电机的反电势过零检测方法包括以下步骤：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，在对无刷直流电机控制的过程中，在每个PWM控制周期内获取无刷直流电机的PWM控制信号的占空比，并判断占空比是否大于第一占空比。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，如果占空比大于第一预设占空比，则执行步骤S21、步骤S22和步骤S23中的任任意一个步骤，其中，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

步骤S21为，在PWM控制周期的高电平时间内通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零。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.

步骤S22为，在PWM控制周期的高电平时间内通过ADC模块的FIFO多通道采样功能对无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果判断反电势是否过零。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. .

步骤S23为，在PWM控制周期内通过硬件触发方式触发ADC单通道每隔预设时间间隔对无刷直流电机的反电势进行采样，并在每次采样完成后根据采样结果判断反电势是否过零。其中，PWM控制信号为中心对称的PWM控制信号。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.

根据本申请的一个实施例，如果占空比小于第二预设占空比，则在PWM控制周期的高电平时间内通过常规反电势采样方法对无刷直流电机的反电势进行一次采样，并根据采样结果判断反电势是否过零，其中，第二预设占空比小于第一预设占空比，具体可根据实际情况进行标定。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.

具体地，目前反电势过零检测是比较悬空相端电压与参考电压的关系。以A相为例，在一个周期内A相绕组端电压波形如图2a所示，其中在BC和CB期间，A相悬空，其端电压波形如图2b所示。在PWM开通期间，A相端电压U _A＝e _A+1/2U _DC，当U _A＝1/2U _DC时，e _A＝0，即为A相反电势过零时刻；在PWM关断期间，A相端电压U _A＝e _A，当U _A＝0时，即为A相反电势过零时刻。因此，在PWM开通期间进行反电势过零检测，参考电压选择1/2U _DC，在PWM关断期间进行反电势过零检测，参考电压选择0V。 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.

相关技术中，当使用ADC模块在每个PWM控制周期内采样一次悬空相的端电压，并将采样结果与参考电压进行比较，以判断反电势是否过零时，以在PWM开通期间检测反电势过零为例。如图2所示，在BC导通期间，A相端电压呈上升趋势，在每个PWM开通期间对A相端电压进行一次采样，并与参考电压进行比较，在图2b中的a1时刻，U _A＜1/2U _DC，反电势未过零，在下一PWM控制周期的a2时刻，U _A＞1/2U _DC，此时检测到反电势已过零；同理，在CB导通期间，A相端电压呈下降趋势，在b2时刻，U _A＞1/2U _DC，反电势未过零，而在b3时刻，U _A＜1/2U _DC，此时检测到反电势已过零。 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.

上述检测到的反电势过零时刻均滞后实际的反电势过零时刻约一个PWM控制周期，在转速较低(占空比较低)的情况下，一个换相间隔内有多个PWM控制周期，因此滞后一个PWM控制周期对换相影响较小。但是，当无刷直流电机以极高转速运行时，如100000RPM(1对极)，此时一个相位扇区的时间是100us，而一个PWM控制周期是50us(即20KHz，无刷直流电机的PWM控制信号的频率一般在5～30KHz范围内，再提高会对功率开关管的开关损耗、效率以及散热等造成不利)，此时一个换相间隔内最多有2个PWM控制周期，而每个PWM控制周期只进行一次反电势过零采样，因而无法及时获知反电势是否过零，从而很容易因反电势过零检测滞后较大引起无刷直流电机失步。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.

具体而言，如图3所示，当无刷直流电机以极高转速运行时，一个换相间隔内只有2个PWM控制周期，如果按照常规反电势采样方法，即在这两个PWM控制周期内均进行一次反电势AD采样，分别对应c1、c2时刻，而实际反电势过零发生在c1时刻之后，因此无法在第一个PWM控制周期内及时检测到反电势过零，只能在第二个PWM控制周期的c2时刻检测到反电势过零，而c2时刻滞后真正的反电势过零点约1个PWM控制周期(约为1/2换相间隔)，导致反电势过零检测滞后，继而导致换相滞后，引起电流脉动大甚至失步等不良状况。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.

因此，在本申请的实施例中，可将无刷直流电机的运行划分为两个阶段，分别为低速阶段和高速阶段，进一步地，根据PWM控制信号的占空比，可将无刷直流电机的运行划分为低占空比阶段和高占空比阶段。其中，在低占空比阶段(即，低速阶段)，仍采用常规反电势采样方法，例如，在每个PWM控制周期的高电平时间内进行一次反电势AD采样，并根据采样结果判断反电势是否过零。而当占空比升高至超过第一预设占空比时，进入高占空比阶段(即，高速阶段)，在该阶段内，此时在每个PWM控制周期的高电平时间内，利用ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零，或者利用ADC模块的FIFO多通道采样功能对无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果判断反电势是否过零，或者在整个PWM控制周期内通过硬件触发方式触发ADC单通道每隔第一预设时间对无刷直流电机的反电势进行采样，并在每次采样完成后根据采样结果判断反电势是否过零。当占空比再次下降至低于第二预设占空比时，再使用常规反电势采样方法，其中，第二预设占空比小于第一预设占空比。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.

由于低占空比阶段的反电势过零检测滞后对无刷直流电机的换相几乎没有影响，所以在无刷直流电机低速运行阶段，采用常规反电势采样方法就可满足控制需求，而在高占空比阶段，可通过采用ADC模块的单通道在每个PWM控制周期的高电平时间内连续多次采样反电势，或者通过采用ADC模块的FIFO多通道采样功能，并在每个PWM控制周期的高电平期间进行连续多次采样反电势，或者通过硬件触发方式触发ADC单通道在每个PWM控制周期内多次采样反电势，因而可以保证反电势过零检测的及时性和准确性，可支持无刷直流电机稳定运行在极高转速范围内，并且无需额外增加比较器，能够降低成本，减小控制器PCB的尺寸。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.

下面结合图4-图6来详细说明如何在PWM控制周期的高电平时间内通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零。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.

根据本申请的一个实施例，在PWM控制周期的高电平时间内通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零，包括：判断是否进入反电势过零检测阶段；如果是，则获取无刷直流电机的母线电压，并将ADC模块的单通道配置为当前悬空相端电压对应的AD通道，并触发ADC模块的单通道对无刷直流电机的反电势进行第一次采样；在第一次采样完成后，获取第一次采样结果，同时触发ADC模块的单通道对无刷直流电机的反电势进行第二次采样，并在第二次采样的过程中根据第一次采样结果和母线电压判断反电势是否过零；如果反电势过零，则退出反电势过零检测阶段。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.

根据本申请的一个实施例，如果反电势未过零，则在第i-1次采样完成后，获取第i-1次采样结果，同时触发ADC模块的单通道对无刷直流电机的反电势进行第i次采样，并在第i次采样的过程中根据第i-1次采样结果和母线电压判断反电势是否过零，直至判断出反电势过零或者采样次数大于等于预设次数退出反电势过零检测阶段，其中，i为大于等于3 的整数。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.

根据本申请的一个实施例，无刷直流电机的反电势过零检测方法还可包括：判断当前时间是否为PWM控制周期的高电平开始时间；如果当前时间为PWM控制周期的高电平开始时间，则在延时第一预设时间后触发母线电压AD采样，并在母线电压AD采样完成后进入反电势过零检测阶段。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.

具体而言，参考图4所示，在采用PWM控制信号对无刷直流电机控制的过程中，可以通过PWM的计数单元来判断当前时间是否为PWM控制周期的高电平开始时间，如果是，则在延时第一预设时间(时间的长短由软件程序配置，例如4us)后触发母线电压AD采样(母线电压的1/2作为反电势过零检测的参考电压)。其中，设置在第一预设时间后对母线电压进行AD采样是为了避免受功率开关管开关的影响导致母线电压采样不准确。而在第一预设时间内，可对PWM控制信号的占空比进行比较判断，如果占空比小于第二预设占空比，则采用常规反电势采样方法判断反电势是否过零，如，在对母线电压AD采样完成后进入反电势过零检测阶段，此时采用ADC模块的单通道对悬空相端电压进行一次采样，并将采样结果与母线电压进行比较，以判断反电势是否过零；如果占空比大于第一预设占空比，则在对母线电压AD采样完成后进入反电势过零检测阶段，此时采用ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零。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.

具体地，继续参考图4所示，在母线电压AD采样完成(约为1us)后自动产生AD中断，在进入AD中断后，读取母线电压的AD采样结果，并将ADC模块的单通道配置为当前悬空相端电压对应的AD通道，以为后续连续多次的反电势采样做准备。首先，触发ADC模块的单通道对无刷直流电机的反电势进行第一次采样，并在第一采样完成后，读取第一次采样结果，同时触发ADC模块的单通道对无刷直流电机的反电势进行第二次采样，并在第二次采样的过程中根据第一次采样结果和母线电压进行比较以判断反电势是否过零，如果反电势过零，则退出AD中断，当前PWM控制周期的反电势过零检测结束。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.

如果反电势未过零，则在第二次采样结束后，读取第二次采样结果，并触发ADC模块的单通道对无刷直流电机的反电势进行第三次采样，并在第三次采样的过程中根据第二次采样结果和母线电压判断反电势是否过零，如果反电势过零，则退出AD中断；如果反电势未过零，则在第三次采样结束后，读取第三次采样结果，并触发ADC模块的单通道对无刷直流电机的反电势进行第四次采样，…，在第i-1次采样完成后，获取第i-1次采样结果，同时触发ADC模块的单通道对无刷直流电机的反电势进行第i次采样，并在第i次采样的过程中根据第i-1次采样结果和母线电压判断反电势是否过零，直至判断出反电势过零或者采样次数大于等于预设次数，退出AD中断。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.

在下一个PWM控制周期开始时，重复上述过程。The above process is repeated at the beginning of the next PWM control cycle.

在上述实施例中，在第i-1次采样完成时获取第i-1次采样结果，同时触发第i次反电势的采样，这样在利用第i-1次采样结果进行反电势过零判断的同时，第i次反电势的采样及转换也在自动进行，有利于在PWM控制周期的高电平时间内尽可能多的采集反电势，这种连续多次的单通道反电势AD采样，可以在每个单通道反电势AD采样完成时就进行反电势过零判断，因而能够及时检测到反电势过零，从而使得换相更加精准，进而使得无刷直流电机能够稳定运行在极高转速，而且无需额外增加比较器，能够降低成本。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.

需要说明的是，上述实施例中的预设次数可根据一次单通道AD采样及反电势过零判断所需时间和当前PWM控制周期的高电平时间进行标定。举例而言，假设一次单通道AD采样及反电势过零判断所需时间为Δt，当前PWM控制周期的高电平时间为T，则连续单通道反电势采集及过零判断次数N＝T/Δt，即预设次数为T/Δt(取整数，不足一次的舍去)，当采样次数大于等于T/Δt时，退出反电势过零检测阶段，当前PWM控制周期的反电势过零检测结束。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. .

如图5所示，该无刷直流电机的反电势过零检测方法可包括以下步骤：As shown in FIG. 5, the back EMF zero-crossing detection method of the brushless DC motor may include the following steps:

S101，读取母线电压AD采样结果，以及配置单通道反电势AD采样，并将单通道反电势采样累计次数置0。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，判断当前反电势AD采样是否结束。如果是，则执行步骤S103；如果否，则继续执行步骤S102。S102. Determine whether the current back EMF AD sampling ends. If yes, step S103 is performed; if no, step S102 is continued.

S103，判断当前反电势采样次数是否小于N。如果是，则执行步骤S104；如果否，则当前PWM控制周期的反电势过零检测结束，退出AD中断。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，读取反电势AD采样结果，同时触发下一次的反电势AD采样，并将当前单通道反电势采样累计次数加1。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，根据反电势AD采样结果判断反电势是否过零。如果是，则当前PWM控制周期的反电势过零检测结束，退出AD中断；如果否，则返回步骤S102。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.

图6是根据本申请实施例的极高转速下无刷直流电机的反电势过零检测的示意图，如图6所示，在一个PWM控制周期内通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，能够及时精准地检测到反电势过零点，从而保证无刷直流电机能够稳定运行在极高转速下，同时不需要外加比较器，降低了成本。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.

根据本申请的一个实施例，在PWM控制周期的高电平时间内，还判断无刷直流电机的续流时间是否结束，并在续流时间结束后，通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，以及在采样的过程中根据上一次采样结果判断反电势是否过零。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.

具体而言，当无刷直流电机进入高占空比阶段(即，高速阶段)，在该阶段内，由于无刷直流电机换相后存在一个续流过程，在该续流期间悬空相端电压被强行拉到母线电压或者电源地，导致部分反电势波形被湮没，因此在续流期间进行反电势采样是无效的，可等续流时间结束后再对无刷直流电机的反电势进行连续多次采样，这样能够节省CPU资源。因此，在高占空比阶段，在每个PWM控制周期的高电平时间内，避开续流时间，然后利用ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零。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.

下面结合图7-图9来详细说明如何在PWM控制周期的高电平时间内避开续流时间通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零。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.

参考图7a-图7b所示，在采用PWM控制信号对无刷直流电机控制的过程中，可以通过PWM的计数单元来判断当前时间是否为PWM控制周期的高电平开始时间，如果是，则在延时第一预设时间(时间的长短由软件程序配置，例如4us)后触发母线电压AD采样(母线电压的1/2作为反电势过零检测的参考电压)。其中，设置在第一预设时间后对母线电压进行AD采样是为了避免受功率开关管开关的影响导致母线电压采样不准确。而在第一预设时间内，可对PWM控制信号的占空比进行比较判断，如果占空比小于第二预设占空比，则采用常规反电势采样方法判断反电势是否过零，如，在对母线电压AD采样完成后进入反电势过零检测阶段，此时采用ADC模块的单通道对悬空相端电压进行一次采样，并将采样结果与母线电压进行比较，以判断反电势是否过零；如果占空比大于第一预设占空比，则在对母线电压AD采样完成后进入反电势过零检测阶段，在该阶段内，先避开续流时间，然后再通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零。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.

具体地，继续参考图7a-图7b所示，在母线电压AD采样完成(约为1us)后自动产生AD中断，在进入AD中断后，读取母线电压的AD采样结果，并将ADC模块的单通道配置为当前悬空相端电压对应的AD通道，为后续连续多次的单通道反电势AD采样做准确。然后，根据续流时间与AD中断发生的前后关系分为两种情况。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.

第一种情况，如图7a所示，在进入AD中断之后续流时间已经结束(对应的续流时间结束标志位已经被置位)，则在AD中断中进行连续多次的单通道反电势AD采样。其中，具体采样过程可参见上述实施例中图4所示的采样过程，为避免冗余，在此不再详述。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.

第二种情况，如图7b所示，在进入AD中断之后续流时间尚未结束(对应的续流时间结束标志位未置位)，则退出AD中断，一旦续流时间结束，则自动进入避开续流延时中断TF，并在续流延时中断TF中先置位续流时间结束标志位，然后进行连续多次的单通道反电势AD采样，具体采样过程可参见前述，这里就不再进行详细描述。为使本领域技术人员更清楚的了解本申请，下面结合本申请的具体示例来对无刷直流电机的反电势过零检测方法做进一步说明。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.

具体地，如图8a所示，无刷直流电机的反电势过零检测方法可包括以下步骤：Specifically, as shown in FIG. 8a, the back EMF zero-crossing detection method of the brushless DC motor may include the following steps:

S201，判断续流时间是否结束。如果是，则执行步骤S502；如果否，则退出AD中断。S201. Determine whether the freewheeling time ends. If yes, go to step S502; if no, exit AD interrupt.

S202，触发单通道反电势AD采样。S202, triggering single channel back EMF AD sampling.

S203，判断当前反电势AD采样是否结束。如果是，则执行步骤S204；如果否，则继续执行步骤S203。S203. Determine whether the current back EMF AD sampling ends. If yes, step S204 is performed; if no, step S203 is continued.

S204，读取反电势AD采样结果。S204, reading the back EMF AD sampling result.

S205，根据反电势AD采样结果判断反电势是否过零。如果是，则执行步骤S207；如果否，则执行步骤S206。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，判断当前PWM控制周期的高电平时间是否结束。如果是，则退出AD中断；如果否，则返回步骤S502。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，退出AD采样以及对反电势过零时间进行处理。S207, exiting the AD sampling and processing the back EMF zero crossing time.

S208，将过零检测成功标志位置位，并清除续流结束标志位。S208, the zero-crossing detection success flag is set, and the free-wheeling end flag is cleared.

S209，设置延时换相中断TP。S209, setting a delay commutation interrupt TP.

进一步地，在检测到反电势过零后，进入延时换相中断TP，以控制无刷直流电机进行换相，如图8b所示，其具体的方法可包括以下步骤：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，判断过零检测成功标志位是否被置位。如果是，则执行步骤S602；如果否，则退出延时换相中断TP。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，控制无刷直流电机进行换相操作。S302, controlling the brushless DC motor to perform a commutation operation.

S303，更新相位。S303, update the phase.

S304，清除过零检测成功标志位。S304. Clear the zero-crossing detection success flag.

S305，设置避开续流延时中断TF。S305, setting to avoid the freewheeling delay interrupt TF.

如图8c所示，在进入AD中断之后续流时间尚未结束无刷直流电机的反电势过零检测方法可包括以下步骤：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，设置续流时间结束标志位。S401, setting a freewheeling time end flag.

S402，停止避开续流延时中断TF。S402, stopping to avoid the freewheeling delay interrupt TF.

S403，判断是否处于PWM控制周期的高电平时间内。如果是，则执行步骤S404；如果否，则退出避开续流延时中断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，触发单通道反电势AD采样。S404, triggering single channel back EMF AD sampling.

S405，判断当前反电势AD采样是否结束。如果是，则执行步骤S406；如果否，则继续执行步骤S405。S405. Determine whether the current back EMF AD sampling ends. If yes, step S406 is performed; if no, step S405 is continued.

S406，读取反电势AD采样结果。S406, reading the back EMF AD sampling result.

S407，根据反电势AD采样结果判断反电势是否过零。如果是，则执行步骤S409。如果否，则执行步骤S408。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，判断当前PWM控制周期的高电平时间是否结束。如果是，则退出避开续流延时中断TF；如果否，则返回步骤S404。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，退出AD采样以及对反电势过零时间进行处理。S409, exiting the AD sampling and processing the back EMF zero crossing time.

S410，将过零检测成功标志位置位，并清除续流结束标志位。S410, the zero-crossing detection success flag is set, and the free-wheeling end flag is cleared.

S411，设置延时换相中断TP。S411, setting a delay commutation interrupt TP.

由此，在每个PWM控制周期内，可根据续流结束时间与产生AD中断的时间的前后关系判断产生AD中断后续流时间是否结束，然后根据判断结果通过上述不同的方式对无刷直流电机进行反电势过零检测，以实现避开续流时间进行反电势过零判断的目的。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.

图9是根据本申请实施例的极高转速下无刷直流电机的反电势过零检测的示意图，如图9所示，在无刷直流电机实际运行的过程中，每次换相之后存在一个续流过程，在该续流期间悬空相端电压被强行拉到母线电压或者电源地，导致部分反电势波形被湮没，因此在续流期间进行反电势采样是无效的，可等续流时间结束后立即对无刷直流电机的反电势进行连续多次采样，这样既能够节省CPU资源，又能够保证及时准确地检测到反电势过零点，从而保证无刷直流电机能够稳定运行在极高转速下，同时不需要外加比较器，降低了成本。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.

下面结合图10-图12来详细说明如何在PWM控制周期的高电平时间内通过ADC模块的FIFO多通道采样功能对无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果判断反电势是否过零。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.

根据本申请的一个实施例，在PWM控制周期的高电平时间内通过ADC模块的FIFO多通道采样功能对无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果判断反电势是否过零，包括：判断是否进入反电势过零检测阶段；如果是，则获取无刷直流电机的母线电压，并将FIFO的M1个通道配置为当前悬空相端电压对应的AD通道，在配置完成后，ADC模块对FIFO的M1个通道进行连续采样以对无刷直流电机的反电势进行多次采样，其中，M1小于等于FIFO的总通道数；在对无刷直流电机的反电势进行多次采样完成后，获取FIFO的M1个通道的采样结果，并根据采样结果和母线电压判断反电势是否过零；如果反电势过零，则退出反电势过零检测阶段。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.

根据本申请的一个实施例，如果反电势未过零，则根据PWM控制周期的高电平时间对FIFO的M2个通道进行配置，并通过FIFO的M2个通道继续对无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果和母线电压判断反电势是否过零，其中，M2 为小于等于M1的整数。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.

根据本申请的一个实施例，无刷直流电机的反电势过零检测方法还包括：判断当前时间是否为PWM控制周期的高电平开始时间；如果当前时间为PWM控制周期的高电平开始时间，则在延时第一预设时间后触发母线电压AD采样，并在母线电压AD采样完成后进入反电势过零检测阶段。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.

具体而言，参考图10所示，在采用PWM控制信号对无刷直流电机控制的过程中，可以通过PWM的计数单元来判断当前时间是否为PWM控制周期的高电平开始时间，如果是，则在延时第一预设时间(时间的长短由软件程序配置，例如4us)后触发母线电压AD采样(母线电压的1/2作为反电势过零检测的参考电压)。其中，设置在第一预设时间后对母线电压进行AD采样是为了避免受功率开关管开关的影响导致母线电压采样不准确。而在第一预设时间内，可对PWM控制信号的占空比进行比较判断，如果占空比小于第二预设占空比，则采用常规反电势采样方法判断反电势是否过零，如，在对母线电压AD采样完成后进入反电势过零检测阶段，此时采用ADC模块的单通道对悬空相端电压进行一次采样，并将采样结果与母线电压进行比较，以判断反电势是否过零；如果占空比大于第一预设占空比，则在对母线电压AD采样完成后进入反电势过零检测阶段，此时通过ADC模块的FIFO多通道采样功能对无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果判断反电势是否过零。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.

具体地，继续参考图10所示，在母线电压AD采样完成(约为1us)后自动产生AD中断，该中断可称为第一次AD中断。在进入第一次AD中断后，读取母线电压的AD采样结果，并将FIFO的8个通道配置为当前悬空相端电压对应的AD通道，然后退出第一次AD中断。在配置完成后，ADC模块将自动对配置好的FIFO的8个通道进行连续采样，即在一段采样时间内，连续采集8个悬空相端电压的值，以对无刷直流电机的反电势进行多次采样。当ADC模块采样完成后会再次产生AD中断，该中断可称为第二次AD中断。在进入第二次AD中断后，读取FIFO的8个通道的采样结果，即8个悬空相端电压的值，并将8个悬空相端电压的值分别与母线电压进行比较，以判断反电势是否过零。如果反电势过零，则退出第二次AD中断，当前PWM控制周期的反电势过零检测结束。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.

如果反电势未过零，则根据当前PWM控制周期的高电平时间(即，PWM控制信号的占空比)来确定对反电势进行再次检测时所需的FIFO的通道个数，以确保在PWM控制周期的高电平时间内尽可能多地采集无刷直流电机的反电势。例如，如图10所示，根据当前PWM控制周期的高电平剩余时间可以确定需要M2(如，3)个通道，则将M2个通道配置为当前悬空相端电压对应的AD通道，然后退出第二次AD中断。在配置完成后，ADC模块将自动对配置好的FIFO的M2个通道进行连续采样，即在一段采样时间内，连续采集 M2个悬空相端电压的值，以对无刷直流电机的反电势进行再次采样。当ADC模块采样完成后会再次产生AD中断，该中断可称为第三次AD中断。在进入第三次AD中断后，读取FIFO的M2个通道的采样结果，即M2个悬空相端电压的值，并将M2个悬空相端电压的值分别与母线电压进行比较，以判断反电势是否过零，至此，当前PWM控制周期的反电势过零检测阶段结束。在下一个PWM控制周期开始时，重复上述过程。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.

如图11所示，该无刷直流电机的反电势过零检测方法可包括以下步骤：As shown in FIG. 11, the back EMF zero-crossing detection method of the brushless DC motor may include the following steps:

S501，判断当前是否处于第一次AD中断。如果是，则执行步骤S502；如果否，则执行步骤S503。S501. Determine whether the current AD interrupt is currently in use. If yes, go to step S502; if no, go to step S503.

S502，读取母线电压AD采样结果，并配置8通道FIFO AD采样，以为进入第二次中断做准备。S502, reading the bus voltage AD sampling result, and configuring 8-channel FIFO AD sampling to prepare for entering the second interrupt.

S503，判断是否处于第二次AD中断。如果是，则执行步骤S504；如果否，则执行步骤S508。S503, determining whether it is in the second AD interrupt. If yes, go to step S504; if no, go to step S508.

S504，读取8通道FIFO AD采样结果。S504, reading the 8-channel FIFO AD sampling result.

S505，根据8通道FIFO AD采样结果判断反电势是否过零。如果是，则执行步骤S506；如果否，则执行步骤S507。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，准备进入第一次AD中断，以为下一PWM控制周期内的反电势进行过零检测。S506, ready to enter the first AD interrupt to perform zero-crossing detection for the back EMF in the next PWM control period.

S507，根据当前PWM占空比配置相应的M2通道FIFO AD采样，为进入第三次AD中断做准备。其中，M2为小于等于8的整数。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，判断当前是否处于第三次AD中断。如果是，则执行步骤S509；如果否，则退出当前AD中断。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，读M2通道FIFO AD采样结果，并根据采样结果判断反电势是否过零。S509, reading the M2 channel FIFO AD sampling result, and judging whether the back EMF is zero-crossing according to the sampling result.

图12是根据本申请实施例的极高转速下无刷直流电机的反电势过零检测的示意图，如图12所示，采用ADC模块的FIFO多通道采样功能实现在一个PWM控制周期的高电平时间内对无刷直流电机的反电势进行连续多次采集，能够及时精准地检测到反电势过零点，从而保证无刷直流电机能够稳定运行在极高转速下，同时不需要外加比较器，降低了成本。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.

需要说明的是，在上述实施例中，M1的取值为8，而在实际应用中，M1可以设置为4、5、6、7和8中任何一个FIFO深度，这样可以根据实际的PWM控制信号的占空比在一个PWM控制周期内多次触发反电势采样中断，例如，M1的取值可以为4，那么相对于上述具体示例，就可以多触发一次，使得无刷直流电机的反电势过零检测更加及时准确。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.

下面结合图13-图14来详细说明如何在PWM控制周期内通过硬件触发方式触发ADC单通道对无刷直流电机的反电势进行多次采样，并在每次采样完成后根据采样结果判断反电势是否过零，以及在PWM控制周期的高电平中间时刻获得无刷直流电机的母线电流。其中，PWM控制信号为中心对称的PWM控制信号，也就是说，在每个PWM控制周期内均是采用中心对称的PWM控制信号对无刷直流电机进行控制的。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.

根据本申请的一个实施例，在每隔预设时间间隔对无刷直流电机的反电势进行采样的过程中，还判断当前时间是否为PWM控制周期的高电平中间时刻，如果是，则停止对无刷直流电机的反电势进行采样，并触发母线电流ADC采样以获得无刷直流电机的母线电流。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.

具体而言，如图13所示，在每个PWM控制周期的高电平时间内，母线电流的波形大致为线性上升，因此每个PWM控制周期的高电平中间时刻对应的母线电流瞬时值可近似为母线电流平均值。而为了便于实现母线电流平均值的准确采样，实现无刷直流电机的恒功率控制，在每个PWM控制周期内采用中心对称的PWM控制信号对无刷直流电机进行控制，并在每隔预设时间间隔对无刷直流电机的反电势进行采样的过程中，判断当前时间是否为PWM控制周期的高电平中间时刻(或者，距离中间时刻的一段时间内)，如果是，则触发母线电流ADC采样以获得无刷直流电机的母线电流。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.

根据本申请的一个实施例，上述的无刷直流电机的反电势过零检测方法还包括：判断当前时间是否为PWM控制周期的开始时间，如果是，则触发母线电压ADC采样以获得无刷直流电机的母线电压，并对ADC单通道进行配置以使ADC单通道每隔预设时间间隔对无刷直流电机的反电势进行采样，配置完成后，ADC单通道开始每隔预设时间间隔对无刷直流电机的反电势进行采样，并根据采样结果和母线电压判断反电势是否过零，同时判断反电势的采样次数是否大于等于第一预设次数，其中，第一预设次数根据PWM控制周期和预设时间间隔获取；如果反电势的采样次数大于等于第一预设次数，则判断当前时间为PWM控制周期的高电平中间时刻。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.

根据本申请的一个实施例，在获得无刷直流电机的母线电流后，还对ADC单通道进行配置以使ADC单通道每隔预设时间间隔对无刷直流电机的反电势进行采样；配置完成后，ADC单通道开始每隔预设时间间隔对无刷直流电机的反电势进行采样，并根据采样结果和母线电压判断反电势是否过零，直至判断反电势过零或者进入下一PWM控制周期。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. .

具体而言，参考图13所示，可以通过PWM的计数单元来判断当前时间是否为PWM控制周期的开始时间，如果是，则产生一个PWM中断，即在每个PWM周期的起始时刻会产生一个PWM中断。在该中断中，可触发母线电压ADC采样以获取无刷直流电机的母线电压，并对ADC单通道进行配置以使ADC单通道每隔预设时间间隔(如TWus)对无刷直流电机的反电势进行采样，以及将产生ADC中断的次数清零，然后退出PWM中断。配置完成后，后续会每隔预设时间间隔产生一次ADC中断。在ADC中断的过程中，对无刷直流电机的反电势进行采样，并读取采样结果，以及根据采样结果和母线电压判断反电势是否过零，并累加ADC中断的次数，当ADC中断的次数大于等于第一预设次数时，可判断当前时间为PWM控制周期的高电平中间时刻(或者，距离中间时刻的一段时间内)，此时读取反电势ADC采样结果，并根据采样结果和母线电压判断反电势是否过零，同时触发母线电流ADC采样以获得无刷直流电机的母线电流。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.

需要说明的是，在一定的条件下(例如，PWM中断时间较小，可忽略不计)，上述实施例中的第一预设次数可为N/2，其中，N为PWM控制周期(如Tus)与预设时间间隔(如TWus)的比值，当ADC中断的次数大于等于T/2TW时，可判断当前时间为PWM控制周期的高电平中间时刻(或者，距离中间时刻的一段时间内)。也就是说，在对第一预设次数进行设置时，可结合PWM控制周期、预设时间间隔、PWM中断时间以及母线电流获取时间来进行合理设置，以保证对母线电流的采样尽可能在PWM控制周期的高电平中间时刻或附近，使得母线电流的采样更为准确，保证无刷直流电机的恒功率控制。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.

进一步地，在获得无刷直流电机的母线电流后，再对ADC单通道进行配置以使ADC单通道每隔预设时间间隔继续对无刷直流电机的反电势进行采样，并根据采样结果和母线电压判断反电势是否过零，直至判断反电势过零或者进入下一PWM控制周期。在下一个PWM控制周期重复上述操作。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.

进一步地，如图14a所示，该无刷直流电机的反电势过零检测方法可包括以下步骤：Further, as shown in FIG. 14a, the back EMF zero-crossing detection method of the brushless DC motor may include the following steps:

S601，触发母线电压ADC采样，并将ADC中断次数清零。S601, triggers the bus voltage ADC sampling and clears the number of ADC interrupts.

S602，判断母线电压ADC采样是否结束。如果是，则执行步骤S603；如果否，则继续执行步骤S602。S602. Determine whether the bus voltage ADC sampling ends. If yes, step S603 is performed; if no, step S602 is continued.

S603，读取母线电压ADC采样结果，并配置每隔TWus触发反电势ADC单通道采样。S603, reading the bus voltage ADC sampling result, and configuring the single channel sampling of the back EMF ADC every TWus trigger.

进一步地，在配置完成后，如图14b所示，无刷直流电机的反电势过零检测方法可包括以下步骤：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，读取反电势ADC采样结果，并根据采样结果和母线电压判断反电势是否过零，以及将ADC中断次数加1。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，判断当前ADC中断次数是否等于N/2。如果是，则执行步骤S703；如果否，则退出当前ADC中断。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，触发母线电流ADC采样。S703, triggering bus current ADC sampling.

S704，判断母线电流ADC采样是否结束。如果是，则执行步骤S705；如果否，则继续执行步骤S704。S704, determining whether the bus current ADC sampling ends. If yes, step S705 is performed; if no, step S704 is continued.

S705，读取母线电流ADC采样结果，并配置每隔TWus触发反电势ADC单通道采样。S705, reading the bus current ADC sampling result, and configuring a single channel sampling of the back EMF ADC every TWus trigger.

由此，通过采用连续硬件触发反电势ADC采样方式实现在一个PWM周期内连续多次采集反电势，不仅可以及时精准地检测到反电势过零点，保证无刷直流电机稳定运行在极高转速下，同时能够兼顾母线电流平均值的准确采样，实现无刷直流电机的恒功率控制，而且此方案不需要外加比较器，降低了成本。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.

综上所述，根据本申请实施例的无刷直流电机的反电势过零检测方法，在对无刷直流电机控制的过程中，在每个PWM控制周期内获取无刷直流电机的PWM控制信号的占空比，并判断占空比是否大于第一预设占空比，如果占空比大于第一预设占空比，则在PWM控制周期的高电平时间内通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零，或者在PWM控制周期的高电平时间内通过ADC模块的FIFO多通道采样功能对无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果判断反电势是否过零，或者在PWM控制周期内通过硬件触发方式触发ADC单通道每隔预设时间间隔对无刷直流电机的反电势进行采样，并在每次采样完成后根据采样结果判断反电势是否过零，其中，PWM控制信号为中心对称的PWM控制信号。从而不仅能够及时、准确地检测到反电势过零点，保证电机稳定运行在极高转速，而且无需额外增加比较器，能够降低成本。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.

图15是根据本申请实施例的另一种无刷直流电机的反电势过零检测方法的流程图。如图15所示，本申请实施例的另一种无刷直流电机的反电势过零检测方法，可包括以下步骤：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，在对无刷直流电机控制的过程中，在每个PWM控制周期内获取无刷直流电机的PWM控制信号的占空比，并判断占空比是否大于第一预设占空比。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，如果占空比大于第一预设占空比，则在PWM控制周期的高电平时间内通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零。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.

其中，如何在PWM控制周期的高电平时间内通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零，已在上述实施例中进行了详细说明，具体的过程可参见上述实施例，为避免冗余，在此就不再赘述。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.

根据本申请实施例的无刷直流电机的反电势过零检测方法，在对无刷直流电机控制的过程中，在每个PWM控制周期内获取无刷直流电机的PWM控制信号的占空比，并判断占空比是否大于第一预设占空比，如果占空比大于第一预设占空比，则在PWM控制周期的高电平时间内通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零。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.

另外，本申请的实施例还提出了一种非临时性计算机可读存储介质，其上存储有计算机程序，该程序被处理器执行时实现上述的无刷直流电机的反电势过零检测方法。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.

图16是根据本申请实施例的无刷直流电机的反电势过零检测装置的方框示意图。如图16所示，本申请实施例的无刷直流电机的反电势过零检测装置包括：获取单元100、确认单元200和采样单元300。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.

其中，获取单元100用于在对无刷直流电机控制的过程中，在每个PWM控制周期内获取无刷直流电机的PWM控制信号的占空比；确认单元200用于判断占空比是否大于第一预设占空比；采样单元300用于在占空比大于第一预设占空比时，执行如下操作中的任意一种：在PWM控制周期的高电平时间内通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零；在PWM控制周期的高电平时间内通过ADC模块的FIFO多通道采样功能对无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果判断反电势是否过零；在PWM控制周期内通过硬件触发方式触发ADC单通道每隔预设时间间隔对无刷直流电机的反电势进行采样，并在每次采样完成后根据采样结果判断反电势是否过零，其中，PWM控制信号为中心对称的PWM控制信号。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.

根据本申请的一个实施例，采样单元300还用于，在PWM控制周期的高电平时间内，判断无刷直流电机的续流时间是否结束，并在续流时间结束后，通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，以及在采样的过程中根据上一次采样结果判断反电势是否过零。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.

需要说明的是，本申请实施例的无刷直流电机的反电势过零检测装置中未披露的细节，请参照本申请实施例的无刷直流电机的反电势过零检测方法中所披露的细节，具体这里不再详述。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.

根据本申请实施例的无刷直流电机的反电势过零检测装置，通过获取单元在对无刷直流电机控制的过程中，在每个PWM控制周期内获取无刷直流电机的PWM控制信号的占空比，并通过确认单元判断占空比是否大于第一预设占空比，以及通过采样单元在占空比大于第一预设占空比时，在PWM控制周期的高电平时间内通过ADC模块的单通道对无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果判断反电势是否过零，或者在PWM控制周期的高电平时间内通过ADC模块的FIFO多通道采样功能对无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果判断反电势是否过零，或者在PWM控制周期内通过硬件触发方式触发ADC单通道每隔预设时间间隔对无刷直流电机的反电势进行采样，并在每次采样完成后根据采样结果判断反电势是否过零，其中，PWM控制信号为中心对称的PWM控制信号。从而不仅能够及时、准确地检测到反电势过零点，保证电机稳定运行在极高转速，而且无需额外增加比较器，能够降低成本。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.

另外，本申请的实施例还提出了一种无刷直流电机的控制***，其包括上述的无刷直流电机的反电势过零检测装置。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.

此外，本申请的实施例还提出了一种吸尘器，其包括上述的无刷直流电机的控制***。Furthermore, embodiments of the present application also propose a vacuum cleaner comprising the above described control system for a brushless DC motor.

应当理解，本申请的各部分可以用硬件、软件、固件或它们的组合来实现。在上述实施方式中，多个步骤或方法可以用存储在存储器中且由合适的指令执行***执行的软件或固件来实现。例如，如果用硬件来实现，和在另一实施方式中一样，可用本领域公知的下列技术中的任一项或他们的组合来实现：具有用于对数据信号实现逻辑功能的逻辑门电路的离散逻辑电路，具有合适的组合逻辑门电路的专用集成电路，可编程门阵列(PGA)，现场可编程门阵列(FPGA)等。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.

另外，在本申请的描述中，术语“中心”、“纵向”、“横向”、“长度”、“宽度”、“厚度”、“上”、“下”、“前”、“后”、“左”、“右”、“竖直”、“水平”、“顶”、“底”“内”、“外”、“顺时针”、“逆时针”、“轴向”、“径向”、“周向”等指示的方位或位置关系为基于附图所示的方位或位置关系，仅是为了便于描述本申请和简化描述，而不是指示或暗示所指的装置或元件必须具有特定的方位、以特定的方位构造和操作，因此不能理解为对本申请的限制。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.

此外，术语“第一”、“第二”仅用于描述目的，而不能理解为指示或暗示相对重要性或者隐含指明所指示的技术特征的数量。由此，限定有“第一”、“第二”的特征可以明示或者隐含地包括至少一个该特征。在本申请的描述中，“多个”的含义是至少两个，例如两个，三个等，除非另有明确具体的限定。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.

在本申请中，除非另有明确的规定和限定，术语“安装”、“相连”、“连接”、“固定”等术语应做广义理解，例如，可以是固定连接，也可以是可拆卸连接，或成一体；可以是机械连接，也可以是电连接；可以是直接相连，也可以通过中间媒介间接相连，可以是两个元件内部的连通或两个元件的相互作用关系，除非另有明确的限定。对于本领域的普通技术人员而言，可以根据具体情况理解上述术语在本申请中的具体含义。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.

在本申请中，除非另有明确的规定和限定，第一特征在第二特征“上”或“下”可以是第一和第二特征直接接触，或第一和第二特征通过中间媒介间接接触。而且，第一特征在第二特征“之上”、“上方”和“上面”可是第一特征在第二特征正上方或斜上方，或仅仅表示第一特征水平高度高于第二特征。第一特征在第二特征“之下”、“下方”和“下面”可以是第一特征在第二特征正下方或斜下方，或仅仅表示第一特征水平高度小于第二特征。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.

在本说明书的描述中，参考术语“一个实施例”、“一些实施例”、“示例”、“具体示例”、或“一些示例”等的描述意指结合该实施例或示例描述的具体特征、结构、材料或者特点包含于本申请的至少一个实施例或示例中。在本说明书中，对上述术语的示意性表述不必须针对的是相同的实施例或示例。而且，描述的具体特征、结构、材料或者特点可以在任一个或多个实施例或示例中以合适的方式结合。此外，在不相互矛盾的情况下，本领域的技术人员可以将本说明书中描述的不同实施例或示例以及不同实施例或示例的特征进行结合和组合。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.

尽管上面已经示出和描述了本申请的实施例，可以理解的是，上述实施例是示例性的，不能理解为对本申请的限制，本领域的普通技术人员在本申请的范围内可以对上述实施例进行变化、修改、替换和变型。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

一种无刷直流电机的反电势过零检测方法，其特征在于，包括以下步骤：A method for detecting a zero-crossing zero-crossing of a brushless DC motor, comprising the steps of:

在每个PWM控制周期内获取所述无刷直流电机的PWM控制信号的占空比；Obtaining a duty ratio of a PWM control signal of the brushless DC motor during each PWM control period;

检测并确认所述占空比大于所述第一预设占空比，执行如下操作中的任意一种：Detecting and confirming that the duty ratio is greater than the first preset duty ratio, performing any of the following operations:

在所述PWM控制周期的高电平时间内通过ADC模块的单通道对所述无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果对所述反电势进行过零检测；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;

在所述PWM控制周期的高电平时间内通过ADC模块的FIFO多通道采样功能对所述无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果对所述反电势进行过零检测；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;

在所述PWM控制周期内通过硬件触发方式触发ADC单通道每隔预设时间间隔对所述无刷直流电机的反电势进行采样，并在每次采样完成后根据采样结果对所述反电势进行过零检测，其中，所述PWM控制信号为中心对称的PWM控制信号。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.
如权利要求1所述的无刷直流电机的反电势过零检测方法，其特征在于，在所述PWM控制周期的高电平时间内，检测并确认所述无刷直流电机的续流时间结束，通过ADC模块的单通道对所述无刷直流电机的反电势进行连续多次采样，以及在采样的过程中根据上一次采样结果对所述反电势进行过过零检测。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.
如权利要求1或2所述的无刷直流电机的反电势过零检测方法，其特征在于，所述在所述PWM控制周期的高电平时间内通过ADC模块的单通道对所述无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果对所述反电势进行过零检测，包括：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:

检测并确认所述无刷直流电机进入反电势过零检测阶段，获取所述无刷直流电机的母线电压，并将所述ADC模块的单通道配置为当前悬空相端电压对应的AD通道，并触发所述ADC模块的单通道对所述无刷直流电机的反电势进行第一次采样；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;

第一次采样完成后，获取第一次采样结果，同时触发所述ADC模块的单通道对所述无刷直流电机的反电势进行第二次采样，并在第二次采样的过程中根据所述第一次采样结果和所述母线电压对所述反电势进行过零检测；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;

检测并确认所述反电势过零，退出所述反电势过零检测阶段。The back EMF is detected and confirmed to be zero crossing, and the back EMF zero crossing detection phase is exited.
如权利要求3所述的无刷直流电机的反电势过零检测方法，其特征在于，检测并确认所述反电势未过零，则在当前采样完成后，获取当前采样结果，同时触发所述ADC模块的单通道对所述无刷直流电机的反电势进行下一次采样，并在第下一次次采样的过程中根据所述当前采样结果和所述母线电压对所述反电势进行过零检测，直至确认所述反电势过零或者采样次数大于等于预设次数退出所述反电势过零检测阶段。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.
如权利要求1所述的无刷直流电机的反电势过零检测方法，其特征在于，所述在所述PWM控制周期的高电平时间内通过ADC模块的FIFO多通道采样功能对所述无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果对所述反电势进行过零检测，包括：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:

检测并确认所述无刷直流电机进入反电势过零检测阶段，获取所述无刷直流电机的母线电压，并将所述FIFO的M1个通道配置为当前悬空相端电压对应的AD通道，在配置完成后，所述ADC模块对所述FIFO的M1个通道进行连续采样以对所述无刷直流电机的反电势进行多次采样，其中，M1小于等于所述FIFO的总通道数；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;

对所述无刷直流电机的反电势进行多次采样完成后，获取所述FIFO的M1个通道的采样结果，并根据采样结果和所述母线电压对所述反电势进行过零检测；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;

检测并确认所述反电势过零，退出所述反电势过零检测阶段。The back EMF is detected and confirmed to be zero crossing, and the back EMF zero crossing detection phase is exited.
如权利要求5所述的无刷直流电机的反电势过零检测方法，其特征在于，检测并确认所述反电势未过零，根据所述PWM控制周期的高电平时间对所述FIFO的M2个通道进行配置，并通过所述FIFO的M2个通道继续对所述无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果和所述母线电压对所述反电势进行过零检测，其中，M2为小于等于M1的整数。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.
如权利要求3或5所述的无刷直流电机的反电势过零检测方法，其特征在于，还包括：The method of detecting a zero-crossing zero-crossing of a brushless DC motor according to claim 3 or 5, further comprising:

检测并确认所述当前时间为所述PWM控制周期的高电平开始时间，延时第一预设时间后触发母线电压AD采样，并在所述母线电压AD采样完成后进入所述反电势过零检测阶段。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.
如权利要求1所述的无刷直流电机的反电势过零检测方法，其特征在于，在每隔预设时间间隔对所述无刷直流电机的反电势进行采样的过程中，检测并确认当前时间为所述PWM控制周期的高电平中间时刻，停止对所述无刷直流电机的反电势进行采样，并触发母线电流ADC采样以获得所述无刷直流电机的母线电流。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.
如权利要求8所述的无刷直流电机的反电势过零检测方法，其特征在于，还包括：The method of detecting a zero-crossing zero-crossing of a brushless DC motor according to claim 8, further comprising:

检测并确认当前时间为所述PWM控制周期的开始时间，触发母线电压ADC采样以获得所述无刷直流电机的母线电压，并对所述ADC单通道进行配置以使所述ADC单通道每隔预设时间间隔对所述无刷直流电机的反电势进行采样；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;

配置完成后，所述ADC单通道开始每隔预设时间间隔对所述无刷直流电机的反电势进行采样，并根据采样结果和所述母线电压对所述反电势进行过零检测，同时检测所述反电势的采样次数；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;

检测并确认所述反电势的采样次数大于等于所述第一预设次数，确认当前时间为所述PWM控制周期的高电平中间时刻，其中，第一预设次数根据所述PWM控制周期和所述第二预设时间获取。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.
如权利要求9所述的无刷直流电机的反电势过零检测方法，其特征在于，在获得所述无刷直流电机的母线电流后，还对所述ADC单通道进行配置以使所述ADC单通道每隔所述第二预设时间对所述无刷直流电机的反电势进行采样；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;

配置完成后，所述ADC单通道开始每隔预设时间间隔对所述无刷直流电机的反电势进行采样，并根据采样结果和所述母线电压对所述反电势进行过零检测，直至确认所述反电势过零或者进入下一PWM控制周期。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.
如权利要求1-10中任一项所述的无刷直流电机的反电势过零检测方法，其特征在于，检测并确认所述占空比小于第二预设占空比，在所述PWM控制周期的高电平时间内通过常规反电势采样方法对所述无刷直流电机的反电势进行一次采样，并根据采样结果对所述反电势进行过零检测，其中，所述第二预设占空比小于所述第一预设占空比。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.
一种无刷直流电机的反电势过零检测方法，其特征在于，包括以下步骤：A method for detecting a zero-crossing zero-crossing of a brushless DC motor, comprising the steps of:

在每个PWM控制周期内获取所述无刷直流电机的PWM控制信号的占空比；Obtaining a duty ratio of a PWM control signal of the brushless DC motor during each PWM control period;

检测并确认所述占空比大于所述第一预设占空比，在所述PWM控制周期的高电平时间内通过ADC模块的单通道对所述无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果对所述反电势进行过零检测。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.
一种非临时性计算机可读存储介质，其上存储有计算机程序，其特征在于，该程序被处理器执行时实现如权利要求1-11中任一项所述的无刷直流电机的反电势过零检测方法，或者，如权利要求12所述的无刷直流电机的反电势过零检测方法。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.
一种无刷直流电机的反电势过零检测装置，其特征在于，包括：A back EMF zero-crossing detecting device for a brushless DC motor, comprising:

获取单元，用于在每个PWM控制周期内获取所述无刷直流电机的PWM控制信号的占空比；An acquiring unit, configured to acquire a duty ratio of a PWM control signal of the brushless DC motor in each PWM control period;

确认单元，用于检测并确认所述占空比大于所述第一预设占空比；a confirmation unit, configured to detect and confirm that the duty ratio is greater than the first preset duty ratio;

采样单元，用于根据所述确认单元的确认结果执行如下操作中的任意一种：a sampling unit, configured to perform any one of the following operations according to the confirmation result of the confirmation unit:

在所述PWM控制周期的高电平时间内通过ADC模块的单通道对所述无刷直流电机的反电势进行连续多次采样，并在采样的过程中根据上一次采样结果对所述反电势进行过零检测；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;

在所述PWM控制周期的高电平时间内通过ADC模块的FIFO多通道采样功能对所述无刷直流电机的反电势进行多次采样，并在采样完成后根据采样结果对所述反电势进行过零检测；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;

在所述PWM控制周期内通过硬件触发方式触发ADC单通道每隔预设时间间隔对所述无刷直流电机的反电势进行采样，并在每次采样完成后根据采样结果对所述反电势进行过零检测，其中，所述PWM控制信号为中心对称的PWM控制信号。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.
如权利要求14所述的无刷直流电机的反电势过零检测装置，其特征在于，所述采样单元还用于，在所述PWM控制周期的高电平时间内，检测并确认所述无刷直流电机的续流时间结束，通过ADC模块的单通道对所述无刷直流电机的反电势进行连续多次采样，以及在采样的过程中根据上一次采样结果对所述反电势进行过零检测。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.
一种无刷直流电机的控制***，其特征在于，包括如权利要求14或15所述的无刷直流电机的反电势过零检测装置。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.
一种吸尘器，其特征在于，包括如权利要求16所述的无刷直流电机的控制***。A vacuum cleaner comprising the control system of the brushless DC motor of claim 16.