A brushless direct current motor anti-interference commutation control method and system

Abstract

This invention discloses an anti-interference commutation control method and system for a brushless DC motor, belonging to the field of motor control technology. The method includes: S1. Acquiring historical commutation time intervals of the motor and predicting the motor speed and the theoretical time of the next commutation based on the historical commutation time intervals; S2. Using the predicted theoretical time of the next commutation as the time anchor point, opening an adaptive sampling window in advance, wherein the opening time and duration of the adaptive sampling window are calculated based on the predicted motor speed and the theoretical time of the next commutation; S3. During the opening of the adaptive sampling window, activating the acquisition, latching, and state determination of Hall signals; S4. If a valid transition of the Hall signal is captured in step S3, performing a commutation operation based on the valid transition; and closing the adaptive sampling window after the commutation operation is completed. This invention ensures the dynamic response performance and operational stability of the motor across the entire speed range through active interference avoidance in the time dimension.

Description

Technical Field

[0001] This invention relates to the field of motor control technology, and in particular to an anti-interference commutation control method and system for a brushless DC motor. Background Technology

[0002] Brushless DC motors (BLDC) are widely used in industrial drives, home appliances, electric vehicles, and other fields due to their high efficiency, long lifespan, and low noise. Currently, most brushless DC motors use Hall sensors to detect the rotor position, and the controller triggers commutation based on the changes in the Hall signals, thereby enabling continuous operation of the motor.

[0003] In traditional commutation control strategies, a continuous sampling strategy is typically employed, acquiring Hall signals at a sampling frequency on the order of microseconds. However, in complex real-world industrial environments, factors such as the switching action of power devices and fluctuations in grid voltage can easily generate a large number of transient interference pulses in the Hall signal transmission lines. Because traditional methods process all sampled values ​​indiscriminately, these interference pulses are easily misinterpreted by the control system as valid rotor position signals, leading to problems such as incorrect motor commutation, torque pulsation, and reduced operating efficiency. In severe cases, this can even cause motor runaway.

[0004] To suppress interference, existing technologies often employ hardware RC filter circuits or implement digital filtering algorithms in software. While these methods can suppress interference to some extent, they inevitably introduce additional phase delay (typically 10–50 μs). Under high-speed motor operation, even a small phase delay can lead to commutation lag, preventing the motor from operating at its optimal commutation point and causing performance degradation and efficiency reduction. Therefore, effectively suppressing interference while ensuring commutation accuracy is a pressing technical problem that needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to overcome the technical problems existing in the prior art and provide a brushless DC motor anti-interference commutation control method and system. The method synchronizes the Hall signal acquisition process with the motor commutation event and achieves anti-interference and accurate commutation through a closed-loop control process of "commutation cycle prediction → adaptive sampling window opening → event-driven sampling decision → commutation execution and state reset".

[0006] The objective of this invention is achieved through the following technical solution: A first aspect of the present invention provides a method for anti-interference commutation control of a brushless DC motor, comprising the following steps: S1. Collect the historical commutation time interval of the motor, and predict the motor speed and the theoretical time of the next commutation based on the historical commutation time interval; S2. Using the predicted theoretical time of the next commutation as the time anchor point, the adaptive sampling window is opened in advance. The opening time and duration of the adaptive sampling window are calculated based on the predicted motor speed and the theoretical time of the next commutation. S3. During the period when the adaptive sampling window is open, the acquisition, latching and status determination of the Hall signal are activated; S4. If a valid transition of the Hall signal is captured in step S3, a commutation operation is performed based on the valid transition; and after the commutation operation is completed, the adaptive sampling window is closed.

[0007] In some embodiments, the prediction of the theoretical time of the next commutation includes: Record the actual moment of each successful commutation in the history of the motor, and calculate the average time interval of the most recent N commutations to obtain the real-time average commutation cycle; Based on the actual time of the most recent commutation, and combined with the aforementioned real-time average commutation period, the theoretical time of the next commutation is predicted: in, Indicates the theoretical time of the next commutation. Indicates the actual time of the most recent phase change. This indicates the real-time average commutation period.

[0008] In some embodiments, step S2 further includes: The window parameters are adaptively adjusted according to the real-time speed of the motor. When the motor speed is at the rated speed (real-time speed ≥ 70%), a narrow window is used to reduce the probability of interference. When the motor speed is at the low speed (real-time speed < 70%), a wide window is used to ensure reliable acquisition of the Hall signal and adapt to the full speed range.

[0009] In some embodiments, the prediction of the motor speed includes: in, Indicates the motor speed. This indicates the number of pole pairs of the motor.

[0010] In some embodiments, the opening time of the adaptive sampling window is calculated by the following formula: in, Indicates the start time of the adaptive sampling window. This represents the speed adaptive coefficient, which is applied when the real-time motor speed is ≥70% of the rated speed. Use a value of 0.01~0.02 when the motor's real-time speed is <70% of its rated speed. Use a value of 0.03 to 0.05 to dynamically match different speed requirements.

[0011] In some embodiments, the duration of the adaptive sampling window is calculated by the following formula: in, Indicates the duration of the adaptive sampling window. This indicates the preset proportional coefficient, which is applied when the motor's real-time speed is ≥70% of the rated speed. Use a value of 0.05~0.06 when the motor's real-time speed is <70% of its rated speed. A value of 0.08 to 0.1 is used to balance anti-interference and signal acquisition performance.

[0012] In some embodiments, the time difference between the end time of the adaptive sampling window and the predicted theoretical time of the next commutation is no greater than 0.05. .

[0013] In some embodiments, real-time phase current and bus voltage data are simultaneously collected in step S1, and the historical commutation time interval is weighted and corrected to suppress prediction errors caused by load changes and voltage fluctuations, thereby improving the prediction accuracy of the theoretical commutation time. The motor speed and the theoretical time of the next commutation are then predicted based on the corrected historical commutation time interval.

[0014] A second aspect of the present invention provides an anti-interference commutation control system for a brushless DC motor, comprising: The prediction module is used to collect the historical commutation time intervals of the motor and predict the motor speed and the theoretical time of the next commutation based on the historical commutation time intervals. The adaptive sampling window calculation module is used to open the adaptive sampling window in advance with the predicted theoretical time of the next commutation as the time anchor point. Specifically, it calculates the opening time and duration of the adaptive sampling window based on the predicted motor speed and the theoretical time of the next commutation. The sampling control module is used to activate the acquisition, latching, and state determination of the Hall signal during the opening of the adaptive sampling window; The commutation control module is used to perform a commutation operation based on the valid transition of the Hall signal when a valid transition is captured; and to close the adaptive sampling window after the commutation operation is completed.

[0015] It should be further noted that the technical features corresponding to the above-mentioned options and embodiments can be combined or substituted with each other to form new technical solutions without conflict.

[0016] Compared with the prior art, the beneficial effects of the present invention are: 1. Significantly Improved Reliability: This invention employs an active avoidance strategy of "event-driven + time window". Sampling is only performed within the adaptive sampling window, and the system is in a "dormant" or "interference-immune" state for most of the time. Any random interference pulses on the Hall signal line are physically or logically ignored and will not trigger any control action. This mechanism completely separates the effective signal from noise in the time dimension, eliminating the cause of commutation errors at the root. This method eliminates more than 99% of the causes of commutation errors at the root, achieving high reliability of commutation control. Experimental results show that this method can reduce the motor commutation error rate from 9.3% to below 0.5% while maintaining good dynamic response performance of the system.

[0017] 2. Optimized Operational Performance: Because this invention actively avoids interference through a "time window," rather than passively suppressing interference through RC filtering or software filtering as in existing technologies, it completely eliminates the inherent 10~50μs phase delay in the filtering stage. This means that the commutation action and the actual rotor position are precisely synchronized, completely solving the torque pulsation problem caused by erroneous commutation and ensuring the smoothness and continuity of the motor's output torque. Since no filtering measures are required, the phase delay caused by filtering is eliminated, achieving accurate commutation across the entire speed range of the motor and maintaining good dynamic response performance of the system.

[0018] 3. Full-speed-range adaptive control: The coefficient k compensates for the inherent calculation and response delays of the system, while the coefficient β ensures that the window is narrow enough to eliminate interference, yet wide enough to cover effective signal transitions under all operating conditions. These two coefficients are coupled with the real-time average commutation period, allowing the opening time and duration of the sampling window to dynamically follow changes in motor speed. At high speeds, the window narrows and the lead time decreases, ensuring real-time control; at low speeds, the window widens accordingly, ensuring reliable signal acquisition. This adaptive capability ensures that the motor maintains smooth, continuous torque output and excellent dynamic response performance at any speed.

[0019] 4. Improved economy and practicality: No additional hardware filtering circuits, shielded cables, and high-precision sensors are required. It can be achieved simply by modifying the controller software algorithm, which greatly reduces the cost of hardware materials and the complexity of circuit board design. The core control algorithm can be embedded in the algorithm library of general motor control chips, which has good portability and can be quickly promoted to various brushless DC motor control products, making it highly valuable for industrial application.

[0020] This invention achieves precise synchronization between Hall signal acquisition and commutation events through optimized control logic design, effectively solving the commutation anti-interference problem of brushless DC motors in complex electromagnetic environments, and providing technical support for the application of brushless DC motors in highly interference industrial environments. Attached Figure Description

[0021] Figure 1 This is a flowchart illustrating an anti-interference commutation control method for a brushless DC motor according to an embodiment of the present invention. Detailed Implementation

[0022] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. The components of the embodiments of this application described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] It should be noted that the defects in the solutions in the prior art are all the results of the inventors' practice and careful research. Therefore, the discovery process of the above problems and the solutions proposed by the embodiments of this application in the following text should be the inventors' contributions to this application in the process of invention and creation, and should not be understood as technical content known to those skilled in the art.

[0024] In view of the technical problems pointed out in the background art, the present invention provides the following embodiments: In one exemplary embodiment, an anti-interference commutation control method for a brushless DC motor is provided, such as... Figure 1 As shown, it includes the following steps: S1. Collect the historical commutation time interval of the motor, and predict the motor speed and the theoretical time of the next commutation based on the historical commutation time interval; S2. Using the predicted theoretical time of the next commutation as the time anchor point, the adaptive sampling window is opened in advance. The opening time and duration of the adaptive sampling window are calculated based on the predicted motor speed and the theoretical time of the next commutation. S3. During the period when the adaptive sampling window is open, the acquisition, latching and status determination of the Hall signal are activated; S4. If a valid transition of the Hall signal is captured in step S3, a commutation operation is performed based on the valid transition; and after the commutation operation is completed, the adaptive sampling window is closed.

[0025] Specifically, in step S1, real-time sensing and commutation point prediction are performed. The controller collects historical commutation time intervals to complete the real-time speed estimation of the motor and the accurate prediction of the theoretical moment of the next commutation. The specific implementation process is as follows: 1. Real-time recording and average period calculation: Real-time recording of the actual moment of each successful phase commutation (i=1,2,3...), set the historical commutation data sampling window size N (N is a positive integer from 5 to 20, calibrated according to the motor speed fluctuation characteristics), select the most recent N effective commutation time intervals, and calculate the real-time average commutation cycle using the following formula: in, Let n be the real-time average commutation period obtained after the nth commutation, and n ≥ N.

[0026] 2. Real-time speed estimation: Based on the real-time average commutation period and the number of pole pairs p, the current real-time operating speed of the motor is estimated using the following formula: 3. Theoretical prediction of the next commutation time: The actual time when the nth commutation is completed Using the time base and combining the real-time average commutation period, the theoretical time of the (n+1)th commutation is predicted by the following formula: in, This is the predicted theoretical time of the next commutation.

[0027] Furthermore, in step S1, real-time phase current and bus voltage data are simultaneously collected, and the historical commutation time interval is weighted and corrected to suppress prediction errors caused by load changes and voltage fluctuations, thereby improving the prediction accuracy of the theoretical commutation time. The motor speed and the theoretical time of the next commutation are then predicted based on the corrected historical commutation time interval.

[0028] In step S2, the adaptive sampling window is opened and its parameters are adjusted. Using the predicted theoretical commutation time as the time anchor point, the controller dynamically calculates the sampling window parameters based on the motor's real-time speed and precisely opens the sampling window before the theoretical commutation time arrives. Furthermore, the window parameters are adaptively adjusted segmentally according to the motor's real-time speed. A narrow window is used in the high-speed range (≥70% of rated speed) to reduce the probability of interference introduction, while a wide window is used in the low-speed range (<70% of rated speed) to ensure reliable acquisition of the Hall signal, adapting to the entire speed range. Specifically, the implementation is as follows: 1. Calculation of the adaptive sampling window opening time: To compensate for the computational and execution logic delays of the control chip under high-speed operating conditions, the adaptive sampling window is opened in advance before the theoretical commutation time. The formula for calculating the opening time is as follows: in, The actual opening time of the adaptive sampling window is given by k, which is the speed adaptive coefficient. The value range is 0~0.05, calibrated according to the rated speed of the motor and the calculation speed of the control chip. For example, the value is 0.01~0.02 for the high-speed range and 0.03~0.05 for the low-speed range, dynamically matching different speed requirements.

[0029] 2. Calculation of adaptive sampling window duration: The duration of the adaptive sampling window is set to a fixed proportion of the real-time average commutation period to ensure that the window can effectively capture one effective transition of the Hall signal and avoid most instantaneous interference pulses. The formula is as follows: in, The duration of the sampling window. The scaling factor is recommended to be 0.05 to 0.1. For example, 0.05 to 0.06 is recommended for high-speed segments and 0.08 to 0.1 is recommended for low-speed segments, which balances anti-interference and signal acquisition effects.

[0030] 3. Spatiotemporal characteristics of adaptive sampling windows: The time range of the adaptive sampling window is [ The entire system is located at the predicted commutation theoretical moment. Previously, the time difference between the end of the window and the predicted theoretical commutation time was no greater than 0.05. This ensures that the effective transition range of the rotor position signal is completely covered within the sampling window.

[0031] In step S3, event-driven signal sampling and decision-making are performed. The controller adopts an event-driven selective sampling strategy: the Hall signal sampling circuit is activated only within the time range of the opened sampling window to collect, latch, and determine the status of the Hall signal; outside the sampling window range, the controller closes the Hall signal sampling circuit and enters the interference immunity state. At this time, various interference pulses in the Hall signal transmission line do not participate in the control logic determination, and the control system maintains the current PWM output parameters and motor commutation state unchanged.

[0032] In step S4, commutation is performed and the system state is reset, specifically including: 1. Commutation operation execution: If the controller captures a valid transition of the Hall signal within the adaptive sampling window, it immediately performs a commutation operation according to the commutation logic of the brushless DC motor and updates the motor drive PWM output state.

[0033] 2. System state reset: After the commutation operation is completed, the controller immediately closes the sampling window, restoring the system to an interference-immune state, and simultaneously records the actual moment the commutation is completed. This provides the latest data for calculating the next average commutation period and predicting the theoretical commutation time.

[0034] 3. Wide speed adaptive adaptation: Throughout the commutation control cycle, the opening time and duration of the adaptive sampling window are dynamically adjusted according to the real-time motor speed, using the speed adaptive coefficient k and the proportional coefficient. With real-time average commutation period The coupling control compensates for the control delay at different speeds, ensuring that the motor can achieve precise commutation across the entire speed range.

[0035] In another exemplary embodiment, based on the same inventive concept as the method embodiment, a brushless DC motor anti-interference commutation control system is provided, comprising: The prediction module is used to collect the historical commutation time intervals of the motor and predict the motor speed and the theoretical time of the next commutation based on the historical commutation time intervals. The adaptive sampling window calculation module is used to open the adaptive sampling window in advance with the predicted theoretical time of the next commutation as the time anchor point. Specifically, it calculates the opening time and duration of the adaptive sampling window based on the predicted motor speed and the theoretical time of the next commutation. The sampling control module is used to activate the acquisition, latching, and state determination of the Hall signal during the opening of the adaptive sampling window; The commutation control module is used to perform a commutation operation based on the valid transition of the Hall signal when a valid transition is captured; and to close the adaptive sampling window after the commutation operation is completed.

[0036] The above detailed embodiments are a description of the present invention. It should not be considered that the specific embodiments of the present invention are limited to these descriptions. For those skilled in the art, several simple deductions and substitutions can be made without departing from the concept of the present invention, and all of these should be considered to fall within the protection scope of the present invention.

Claims

1. A method for anti-interference commutation control of a brushless DC motor, characterized in that, Includes the following steps: S1. Collect the historical commutation time interval of the motor, and predict the motor speed and the theoretical time of the next commutation based on the historical commutation time interval; S2. Using the predicted theoretical time of the next commutation as the time anchor point, the adaptive sampling window is opened in advance. The opening time and duration of the adaptive sampling window are calculated based on the predicted motor speed and the theoretical time of the next commutation. S3. During the period when the adaptive sampling window is open, the acquisition, latching and status determination of the Hall signal are activated; S4. If a valid transition of the Hall signal is captured in step S3, a commutation operation is performed based on the valid transition; and after the commutation operation is completed, the adaptive sampling window is closed.

2. The anti-interference commutation control method for a brushless DC motor according to claim 1, characterized in that, The prediction of the theoretical time of the next commutation includes: Record the actual moment of each successful commutation in the history of the motor, and calculate the average time interval of the most recent N commutations to obtain the real-time average commutation cycle; Based on the actual time of the most recent commutation, and combined with the aforementioned real-time average commutation period, the theoretical time of the next commutation is predicted: in, Indicates the theoretical time of the next commutation. Indicates the actual time of the most recent phase change. This indicates the real-time average commutation period.

3. The anti-interference commutation control method for a brushless DC motor according to claim 1, characterized in that, Step S2 also includes: The window parameters are adaptively adjusted in segments according to the real-time speed of the motor. When the real-time speed of the motor is ≥70% of the rated speed, a narrow window is used, and when the real-time speed of the motor is <70% of the rated speed, a wide window is used.

4. The anti-interference commutation control method for a brushless DC motor according to claim 2, characterized in that, The prediction of the motor speed includes: in, Indicates the motor speed. This indicates the number of pole pairs of the motor.

5. The anti-interference commutation control method for a brushless DC motor according to claim 2, characterized in that, The opening time of the adaptive sampling window is calculated by the following formula: in, Indicates the start time of the adaptive sampling window. This represents the speed adaptive coefficient, which is applied when the real-time motor speed is ≥70% of the rated speed. Use a value of 0.01~0.02 when the motor's real-time speed is <70% of its rated speed. Take a value of 0.03 to 0.

05.

6. The anti-interference commutation control method for a brushless DC motor according to claim 2, characterized in that, The duration of the adaptive sampling window is calculated by the following formula: in, Indicates the duration of the adaptive sampling window. This indicates the preset proportional coefficient, which is applied when the motor's real-time speed is ≥70% of the rated speed. Use a value of 0.05~0.06 when the motor's real-time speed is <70% of its rated speed. Take a value of 0.08 to 0.

1.

7. The anti-interference commutation control method for a brushless DC motor according to claim 2, characterized in that, The time difference between the end of the adaptive sampling window and the predicted theoretical time of the next commutation is no greater than 0.

05. .

8. The anti-interference commutation control method for a brushless DC motor according to claim 1, characterized in that, In step S1, real-time phase current and bus voltage data are collected simultaneously, the historical commutation time interval is weighted and corrected, and the motor speed and the theoretical time of the next commutation are predicted based on the corrected historical commutation time interval.

9. A brushless DC motor anti-interference commutation control system, characterized in that, include: The prediction module is used to collect the historical commutation time intervals of the motor and predict the motor speed and the theoretical time of the next commutation based on the historical commutation time intervals. The adaptive sampling window calculation module is used to open the adaptive sampling window in advance with the predicted theoretical time of the next commutation as the time anchor point. Specifically, it calculates the opening time and duration of the adaptive sampling window based on the predicted motor speed and the theoretical time of the next commutation. The sampling control module is used to activate the acquisition, latching, and state determination of the Hall signal during the opening of the adaptive sampling window; The commutation control module is used to perform a commutation operation based on the valid transition of the Hall signal when a valid transition is captured; and to close the adaptive sampling window after the commutation operation is completed.

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