Commutation control method and system for brushless motor, and readable medium

Abstract

A commutation control method and system for a brushless motor, and a readable medium. The method comprises: when driving commutation upon detection of the zero-crossing of back electromotive force fails, acquiring a bus current value and / or a commutation time interval; performing processing on the basis of the acquired bus current value and / or commutation time interval to obtain processed information; and determining whether the processed information satisfies a preset condition, and when the preset condition is satisfied, controlling the motor to perform forced commutation. When commutation disorders occur in a position-sensorless brushless motor under certain working conditions, a certain error correction mechanism is used to correct failed detection and control to ensure normal operation control of the motor, thereby enabling the system to continue operation and increasing the stability of the system.

Description

Commutation control method, system and readable medium for brushless motor Technical Field

[0001] The present invention belongs to the field of brushless DC motor control, and in particular relates to a commutation control method, system and readable medium for a brushless motor. Background Art

[0002] Currently, many power tools and garden tools are controlled by brushless motors without position sensors. The lack of position sensors makes the whole machine more compact, saves costs and simplifies the assembly process.

[0003] However, in certain working conditions, when the torque is insufficient, the load torque is too large, or the load torque increases suddenly, the motor may easily become commutation chaotic. At this time, the back electromotive force of the motor becomes abnormal. If the commutation control is based on the back electromotive force crossing zero, it will cause a huge error in the position judgment of the controller, and the control error will further cause confusion in the motor operation, thus forming a vicious cycle.

[0004] The confusion in positioning inevitably leads to increased current fluctuations, which, when excessive, trigger overcurrent protection. Therefore, from a macroscopic perspective, the machine is prone to shutting down for protection when encountering heavy loads, causing confusion and inconvenience for the user, resulting in a poor user experience.

[0005] Therefore, it is necessary to design a commutation control method, system and readable medium for a brushless motor to solve the above problems. Summary of the Invention

[0006] In response to the deficiencies in the prior art, the present invention aims to provide a commutation control method, system and readable medium for a brushless motor, so as to solve the problem of commutation confusion in a brushless motor without a position sensor under certain working conditions. A certain error correction mechanism is used to correct the failed detection and control, so that the motor operation control is normal, thereby allowing the system to continue to operate, increasing the stability of the system and improving the user experience.

[0007] The technical solution adopted by the present invention to solve the problems of the prior art is:

[0008] A commutation control method for a brushless motor, the method comprising:

[0009] Step 1: If it is detected that the back electromotive force crosses the zero point and the driving commutation fails, the bus current value and / or the commutation time interval are obtained;

[0010] Step 2: Obtain processing information based on the obtained bus current value and / or commutation time interval;

[0011] Step 3: Determine whether the processed information meets the preset conditions. When the preset conditions are met, control the motor to perform forced commutation.

[0012] A further improvement is that the processed information includes the bus current slope value and / or the bus current difference value and / or the bus current instantaneous value and / or the estimated time commutation value. A further improvement is that the processed information includes the bus current slope value, the processed information includes the bus current slope value, and step three includes:

[0013] When the bus current slope value meets a first preset condition, controlling forced commutation;

[0014] The first preset condition is to determine that the bus current slope value changes in a pattern of being greater than zero, approximately equal to zero, and less than zero in sequence.

[0015] A further improved solution is: the processed information includes the bus current slope value, the processed information includes the bus current slope value, and the step three includes:

[0016] When the bus current slope value meets the second preset condition, forced commutation is controlled; the second preset condition is to judge whether the bus current slope value changes in the order of greater than zero, approximately equal to zero, less than zero and greater than zero.

[0017] A further improved solution is: the processed information includes the bus current difference, the processed information includes the bus current difference, and the step three includes:

[0018] When the bus current difference satisfies a third preset condition, forced commutation is controlled; the third preset condition is to judge that the bus current difference changes in a pattern of being greater than zero, approximately equal to zero, and less than zero in sequence;

[0019] A further improved solution is: the processed information includes the bus current difference, the processed information includes the bus current difference, and the step three includes:

[0020] When the bus current difference satisfies a fourth preset condition, forced commutation is controlled; the fourth preset condition is to judge whether the bus current difference changes in the order of being greater than zero, approximately equal to zero, less than zero, and greater than zero.

[0021] A further improved solution is: the processed information includes the bus current slope value, the bus current instantaneous value and the estimated time commutation value, and the step three includes:

[0022] When the bus current slope value satisfies a first preset condition, the bus current instantaneous value satisfies a threshold condition, and the estimated commutation time value satisfies a conditional time, controlling forced commutation;

[0023] The first preset condition is to determine whether the bus current slope value changes in a pattern of being greater than zero, approximately equal to zero, and less than zero in sequence;

[0024] A further improved solution is: the processed information includes the bus current slope value, the bus current instantaneous value and the estimated time commutation value, and the step three includes:

[0025] When the bus current slope value meets the second preset condition and the bus current instantaneous value meets the threshold condition, and the estimated time commutation value meets the time condition, forced commutation is controlled; the second preset condition is to judge that the bus current slope difference changes in the order of greater than zero, approximately equal to zero, less than zero and greater than zero.

[0026] A further improved solution is: the processed information includes a bus current difference, a bus current instantaneous value, and an estimated commutation time value; and step three includes: controlling forced commutation when the bus current difference satisfies a third preset condition, the bus current instantaneous value satisfies a threshold condition, and the estimated commutation time value satisfies a time condition;

[0027] The third preset condition is to determine that the bus current difference changes in a pattern of being greater than zero, approximately equal to zero, and less than zero in sequence;

[0028] A further improvement scheme is: the processing information includes the bus current difference, the bus current instantaneous value and the estimated time commutation value, and the step three includes: when the bus current difference meets the fourth preset condition and the bus current instantaneous value meets the threshold condition, and the estimated time commutation value meets the time condition, controlling forced commutation; the fourth preset condition is to judge that the bus current difference changes in accordance with the rules of being greater than zero, approximately equal to zero, less than zero and greater than zero in sequence.

[0029] Further improvement plan is: a commutation control system of brushless motor,

[0030] It includes detection module, acquisition module, processing module and judgment module.

[0031] The detection module is used to detect the zero-crossing point of the back electromotive force to drive commutation;

[0032] The acquisition module is used to collect bus current values ​​and / or commutation time intervals when the detection module fails;

[0033] The processing module is used to obtain processing information according to the bus current value and / or the commutation time interval;

[0034] The judgment module is used to judge whether the processing information meets a preset condition, and when the preset condition is met, control the motor to perform forced commutation.

[0035] A further improved solution is: the processing information includes the bus current slope value and / or the bus current difference value and / or the bus current instantaneous value and / or the estimated time commutation value.

[0036] A further improvement is as follows: a processing module in a commutation control system of a brushless motor is used to:

[0037] When the bus current slope value meets a first preset condition, controlling forced commutation;

[0038] Or when the bus current slope value meets the second preset condition, controlling forced commutation;

[0039] The first preset condition is to determine whether the bus current slope value changes in a pattern of being greater than zero, approximately equal to zero, and less than zero in sequence;

[0040] The second preset condition is to determine that the bus current slope value changes in the order of being greater than zero, approximately equal to zero, less than zero, and greater than zero.

[0041] A further improved solution is: in a commutation control system of a brushless motor, the processing information includes a bus current difference, and the processing module is used to:

[0042] When the bus current difference satisfies a third preset condition, controlling forced commutation; or when the bus current difference satisfies a fourth preset condition, controlling forced commutation;

[0043] The third preset condition is to judge that the bus current difference changes in the order of being greater than zero, approximately equal to zero, and less than zero; the fourth preset condition is to judge that the bus current difference changes in the order of being greater than zero, approximately equal to zero, less than zero, and greater than zero.

[0044] A further improvement is as follows: in a commutation control system of a brushless motor, the processing information includes:

[0045] bus current slope value, bus current instantaneous value and estimated time commutation value, the processing module is used to:

[0046] When the bus current slope value satisfies a first preset condition, the bus current instantaneous value satisfies a threshold condition, and the estimated commutation time value satisfies a conditional time, controlling forced commutation;

[0047] or when the bus current slope value satisfies a second preset condition, the bus current instantaneous value satisfies a threshold condition, and the estimated time commutation value satisfies a time condition, controlling forced commutation;

[0048] The first preset condition is to determine whether the bus current slope value changes in a pattern of being greater than zero, approximately equal to zero, and less than zero in sequence;

[0049] The second preset condition is to determine that the busbar electrical slope value changes in the order of being greater than zero, approximately equal to zero, less than zero, and greater than zero.

[0050] A further improvement is as follows: in a commutation control system of a brushless motor, the processing information includes:

[0051] bus current difference, bus current instantaneous value and estimated time commutation value, the processing module is used to:

[0052] When the bus current difference satisfies a third preset condition, the bus current instantaneous value satisfies a threshold condition, and the estimated time commutation value satisfies a time condition, controlling forced commutation;

[0053] or when the bus current difference satisfies a fourth preset condition, the bus current instantaneous value satisfies a threshold condition, and the estimated time commutation value satisfies a time condition, controlling forced commutation;

[0054] The third preset condition is to determine that the bus current difference changes in a pattern of being greater than zero, approximately equal to zero, and less than zero in sequence;

[0055] The fourth preset condition is to determine that the bus current difference changes in the order of being greater than zero, approximately equal to zero, less than zero, and greater than zero.

[0056] A further improvement scheme is: a commutation control system for a brushless motor, comprising:

[0057] A collection module, used for collecting bus current values ​​and / or sector time intervals;

[0058] The back electromotive force zero-crossing detection module is electrically connected to the main control module, and is used to detect the back electromotive force zero-crossing point of the motor and output a first signal to the main control module according to the zero-crossing point;

[0059] The main control module is electrically connected to the driving module and the acquisition module, and the main control module includes a signal output module for receiving the first signal and outputting a commutation signal to the driving module;

[0060] The driving module is used to drive the motor to commutate according to the commutation signal;

[0061] The main control module also includes an operation and comparison module, a storage module and an output module;

[0062] The operation and comparison module is used to receive the bus current value and / or the sector time interval and process them to obtain processing information, and the main control module compares the processing information with the preset conditions stored in the storage module;

[0063] The storage module stores the current threshold and the preset condition;

[0064] When the main control module fails to receive the first signal, it determines whether the processing information meets a preset condition. If so, the output module outputs a reversing signal.

[0065] A further improved solution is: the processing information includes the bus current slope value and / or the bus current difference value and / or the bus current instantaneous value and / or the estimated time commutation value.

[0066] A further improvement is as follows: the preset conditions include:

[0067] The first preset condition is to determine whether the bus current slope value changes in a pattern of being greater than zero, approximately equal to zero, and less than zero in sequence;

[0068] The second preset condition is to determine whether the bus current slope value changes in the order of being greater than zero, approximately equal to zero, less than zero, and greater than zero;

[0069] The third preset condition is to determine that the bus current difference changes in a pattern of being greater than zero, approximately equal to zero, and less than zero in sequence;

[0070] The fourth preset condition is to determine that the bus current difference changes in the order of being greater than zero, approximately equal to zero, less than zero, and greater than zero.

[0071] A further improvement is as follows: the preset conditions include:

[0072] The first preset condition is to judge that the bus current slope difference follows a change rule of being greater than zero, approximately equal to zero, and less than zero in sequence; the second preset condition is to judge that the bus current slope difference follows a change rule of being greater than zero, approximately equal to zero, less than zero, and greater than zero in sequence;

[0073] The third preset condition is to determine that the bus current difference changes in a pattern of being greater than zero, approximately equal to zero, and less than zero in sequence;

[0074] The fourth preset condition is to determine that the bus current difference changes in the order of being greater than zero, approximately equal to zero, less than zero, and greater than zero.

[0075] Compared with the prior art, the present invention has the following beneficial effects: through the above-mentioned commutation control method of the brushless motor, that is, when the back electromotive force is detected to cross the zero point and the driving commutation fails, the bus current value and the commutation time interval are processed to obtain processing information, and it is judged whether the processing information meets the preset conditions. When the preset conditions are met, the motor is controlled to perform forced commutation, so that the system can continue to run, the stability of the system is increased, and the user experience is improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0076] The specific embodiments of the present invention are further described in detail below with reference to the accompanying drawings:

[0077] FIG1 is a flowchart showing a method for controlling commutation of a brushless motor according to an embodiment of the present invention;

[0078] FIG2 is a structural schematic diagram of a brushless motor commutation control system according to an embodiment of the present application;

[0079] FIG3 is a second structural diagram of a brushless motor commutation control system according to an embodiment of the present application;

[0080] FIG4 is a waveform diagram showing a brushless motor commutation control system according to an embodiment of the present application. DETAILED DESCRIPTION

[0081] In order to make the technical problems, technical solutions and advantages to be solved by the present invention clearer, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0082] The square wave triggered network distribution method provided in the embodiment of the present application is described in detail below with reference to the accompanying drawings through specific embodiments and their application scenarios.

[0083] FIG1 is a flowchart of a brushless motor commutation control method according to an embodiment of the present application, the steps comprising:

[0084] Step 1: When the drive commutation fails by detecting the back electromotive force zero crossing point, the bus current value and / or commutation time interval are obtained;

[0085] Step 2: Processing the acquired bus current value and / or commutation time interval to obtain processing information;

[0086] Step 3: Determine whether the processed information meets the preset conditions. When the preset conditions are met, control the motor to perform forced commutation.

[0087] Example 1:

[0088] When the back electromotive force is detected to cross zero and the driving commutation fails, K t i , the sampling bus current value I within 0≤i≤K i , 0≤i≤X, perform linear fitting on the multiple sampled bus current values ​​obtained to obtain the corresponding curve slope K, that is, the bus current slope value.

[0089] The first formula for obtaining the busbar current slope value K is: K=(Eti-Et×Ei)÷(Et 2 -(Et) 2 )

[0090] Among them, Eti is the expectation of the product of the sampling time t and the bus current value, Et is the mathematical expectation of the sampling time t, Ei is the mathematical expectation of the bus current, and Et 2 is the mathematical expectation of the square of the sampling time t, (Et) 2 is the square of the mathematical expectation at sampling time t.

[0091] Furthermore, in order to obtain a better judgment effect, a bus current filtering method can be added on the basis of the above. i , 0≤i≤X is the value obtained after filtering. Thus, when the fixed window filter series method is used, ΔT i , 0≤i≤X is the value of X bus current sampling intervals. For example, when the bus current is obtained every 100us, the preset X=8, then the filtered value will be calculated every 800us, ΔT0=ΔT1=ΔT i =800us; When the sliding window filter series method is used, the above preset conditions are still applied, then ΔT0=ΔT1=ΔT i =100us. After each fixed window filtering or sliding window filtering is completed, the slope k is calculated using the above first formula, which is the first-order derivative value of the bus current per unit time.

[0092] After the bus current slope value is obtained by processing the obtained multiple bus current values, it is determined whether the bus current slope value meets a preset condition. If the preset condition is met, the motor is controlled to perform forced commutation.

[0093] The preset conditions are met, that is, when the bus current slope value meets the first preset condition, the forced commutation is controlled; or when the bus current slope value meets the second preset condition, the forced commutation is controlled; the first preset condition is to judge that the bus current slope value changes in the order of greater than zero, approximately equal to zero and less than zero; the second preset condition is to judge that the bus current slope value changes in the order of greater than zero, approximately equal to zero, less than zero and greater than zero.

[0094] When the first preset condition is used for forced commutation, the moment of forced commutation is close to the optimal commutation point or the theoretical commutation point, and the current and voltage waveforms are better controlled. At the same time, the system can continue to run, increase the stability of the system, and improve the user experience; when the second preset condition is used for forced commutation, forced commutation is more reliable, which can avoid false triggering of forced commutation, and at the same time, the system can continue to run, increase the stability of the system, and improve the user experience.

[0095] Please refer to the waveforms shown in Figure 4, which includes three groups of waveforms: the upper, middle, and lower groups. The upper group of waveforms is used to indicate the waveform of the terminal voltage, the middle group of waveforms is used to indicate the bus current waveform before error correction processing, and the lower group of waveforms is used to indicate the bus current waveform after error correction processing provided by the method provided in this application.

[0096] By comparing the three sets of waveforms, it can be clearly seen that the method provided in the present application can make the moment of forced commutation of the current closer to the optimal commutation point or the theoretical commutation point through error correction processing, thereby stabilizing the current and voltage waveforms.

[0097] The waveforms in the lower group of FIG. 4 illustrate the process of detecting the change of the bus voltage slope: if the bus current slope value meets the preset conditions, forced commutation is triggered, specifically:

[0098] Referring to the processing process shown by the blue trend line in the lower group of waveforms in FIG4 , if it is detected that the slope of the bus current gradually becomes greater than zero, then changes to approximately zero, and then changes to less than zero, forced commutation is triggered, that is, the current slope waveform reaches forced commutation point 1 as shown in the figure.

[0099] Referring to the processing process shown by the red trend line in the lower group of waveforms in FIG4 , if it is detected that the slope of the bus current gradually becomes greater than zero, then changes to approximately zero, then changes to less than zero, and then changes to greater than zero, forced commutation is triggered, that is, the current slope waveform reaches forced commutation point 2 as shown in the figure.

[0100] The corresponding forced commutation point 2 lags slightly behind the forced commutation point 1, thereby preventing erroneous triggering of forced commutation and improving the fault tolerance of the circuit.

[0101] The method provided in this application can set two different forced reversing points for the waveform as shown in FIG4 , thereby improving the stability and compatibility of the waveform control.

[0102] Example 2:

[0103] When the back electromotive force is detected to cross zero and the drive commutation fails, the sampled bus current value I within X PWM cycles is obtained. i , 0≤i≤X, perform a difference simplification algorithm on the obtained multiple sampled bus current values ​​to obtain the corresponding bus current difference C.

[0104] The second formula for obtaining the bus current slope value C is: i =I 2i+1 -I 2i , 0≤i≤X

[0105] After the bus current difference is obtained by processing the obtained multiple bus current values, it is determined whether the bus current difference meets a preset condition. If the preset condition is met, the motor is controlled to perform forced commutation.

[0106] When the preset conditions are met, that is, when the bus current slope value meets the third preset condition, the forced commutation is controlled; or when the bus current slope value meets the fourth preset condition, the forced commutation is controlled; the third preset condition is to judge that the bus current difference changes in accordance with the rules of being greater than zero, approximately equal to zero and less than zero in sequence; the fourth preset condition is to judge that the bus current difference changes in accordance with the rules of being greater than zero, approximately equal to zero, less than zero and greater than zero in sequence.

[0107] When the third preset condition is used for forced commutation, the moment of forced commutation is close to the optimal commutation point or the theoretical commutation point, and the current and voltage waveforms are better controlled. At the same time, the system can continue to run, increase the stability of the system, and improve the user experience; when the fourth preset condition is used for forced commutation, forced commutation is more reliable, which can avoid false triggering of forced commutation, and at the same time, the system can continue to run, increase the stability of the system, and improve the user experience.

[0108] Example 3:

[0109] When the back electromotive force is detected to cross zero and the driving commutation fails, K t i , the sampling bus current value I within 0≤i≤K i , 0≤i≤X, perform linear fitting on the multiple sampled bus current values ​​obtained to obtain the corresponding curve slope K, that is, the bus current slope value.

[0110] The first formula for obtaining the busbar current slope value K is: K=(Eti-Et×Ei)÷(Et 2 -(Et) 2 )

[0111] Among them, Eti is the expectation of the product of the sampling time t and the bus current value, Et is the mathematical expectation of the sampling time t, Ei is the mathematical expectation of the bus current, and Et 2 is the mathematical expectation of the square of the sampling time t, (Et) 2 is the square of the mathematical expectation at sampling time t.

[0112] At the same time, the historical sector reversing time interval is obtained, and the historical reversing time interval is processed to obtain the estimated time reversing point.

[0113] At the same time, the instantaneous value of the bus current in each PWM cycle is detected in real time.

[0114] After processing the above information, it is determined whether the bus current slope value, the bus current instantaneous value and the estimated commutation time all meet the preset conditions. If they all meet the preset conditions, the motor is controlled to perform forced commutation.

[0115] The preset condition is met, that is, the bus current slope value meets the first preset condition. The first preset condition is to judge that the bus current slope value changes in the order of greater than zero, approximately equal to zero and less than zero; at the same time, the commutation time reaches the estimated commutation time point, and at the same time, the instantaneous value of the bus current reaches the bus current instantaneous threshold, at this time the motor is controlled to perform forced commutation.

[0116] When forced commutation is performed using the first preset condition, the moment of forced commutation is close to the optimal commutation point or the theoretical commutation point, and the current and voltage waveforms are better controlled. Adding the line current instantaneous threshold and the estimated commutation time point as judgment conditions can better ensure the commutation stability in actual engineering applications and further improve the accuracy and reliability of forced commutation. At the same time, it can also enable the system to continue to operate, increase system stability, and enhance user experience.

[0117] Or the preset condition is that the bus current slope value meets the second preset condition, and the second preset condition is to judge that the bus current slope value changes in the order of greater than zero, approximately equal to zero, less than zero and greater than zero; at the same time, the commutation time reaches the estimated commutation time point, and at the same time, the instantaneous value of the bus current reaches the bus current instantaneous threshold, at this time the motor is controlled to perform forced commutation.

[0118] When forced commutation is performed using the second preset condition, forced commutation is more reliable and can avoid false triggering of forced commutation; adding the line current instantaneous threshold and the estimated commutation time point as judgment conditions can better ensure the commutation stability in actual engineering applications and further improve the accuracy and reliability of forced commutation; at the same time, it can also enable the system to continue to operate, increase system stability, and enhance the user experience.

[0119] Example 4:

[0120] When the back electromotive force is detected to cross zero and the drive commutation fails, the sampled bus current value I within X PWM cycles is obtained. i , 0≤i≤X, perform difference simplification algorithm on the multiple sampled bus current values ​​obtained to obtain the corresponding bus current difference C i .

[0121] The bus current slope value C is obtained i The second formula is: C i =I 2i+1 -I 2i , 0≤i≤X

[0122] At the same time, the historical sector reversing time interval is obtained, and the historical reversing time interval is processed to obtain the estimated time reversing point.

[0123] At the same time, the instantaneous value of the bus current in each PWM cycle is detected in real time.

[0124] After processing the above information, it is determined whether the bus current difference, the bus current instantaneous value and the estimated commutation time all meet the preset conditions. If they do, the motor is controlled to perform forced commutation.

[0125] The preset condition is met, that is, the bus current difference meets the third preset condition. The third preset condition is to judge that the bus current difference changes in a pattern of being greater than zero, approximately equal to zero, and less than zero in sequence; at the same time, the commutation time reaches the estimated commutation time point, and at the same time, the instantaneous value of the bus current reaches the instantaneous threshold of the bus current, at this time, the motor is controlled to perform forced commutation.

[0126] When forced commutation is performed using the third preset condition, the moment of forced commutation is close to the optimal commutation point or the theoretical commutation point, and the current and voltage waveforms are better controlled. Adding the line current instantaneous threshold and the estimated commutation time point as judgment conditions can better ensure the commutation stability in actual engineering applications and further improve the accuracy and reliability of forced commutation. At the same time, it can also enable the system to continue to operate, increase system stability, and enhance the user experience.

[0127] Or the preset condition is satisfied that the bus current difference satisfies the fourth preset condition, and the fourth preset condition is to judge that the bus current difference changes in the order of greater than zero, approximately equal to zero, less than zero and greater than zero; at the same time, the commutation time reaches the estimated commutation time point, and at the same time, the instantaneous value of the bus current reaches the instantaneous threshold of the bus current, at this time the motor is controlled to perform forced commutation.

[0128] When the fourth preset condition is used for forced commutation, forced commutation is more reliable and can avoid false triggering of forced commutation; adding the line current instantaneous threshold and the estimated commutation time point as judgment conditions can better ensure the commutation stability in actual engineering applications and further improve the accuracy and reliability of forced commutation; at the same time, it can also enable the system to continue to operate, increase the system stability, and improve the user experience.

[0129] Refer to Figure 2, which is a structural schematic diagram of a brushless motor commutation control system according to an embodiment of the present application. As can be seen from the figure, the commutation control system of the brushless motor includes a detection module, an acquisition module, a processing module and a judgment module. The detection module is used to detect the zero crossing point of the back electromotive force to drive commutation; the acquisition module is used to collect the bus current value and / or the commutation time interval when the detection module fails; the processing module is used to process the bus current value and / or the commutation time interval to obtain processing information; the judgment module is used to determine whether the processing information meets the preset conditions. When the preset conditions are met, the motor is controlled to perform forced commutation.

[0130] The brushless motor commutation system applies the brushless motor commutation control method. The specific determination method is as described in the first to fourth embodiments.

[0131] Refer to Figure 3, which is a structural schematic diagram of a brushless motor commutation control system according to an embodiment of the present application. As can be seen from the figure, the commutation control system of the brushless motor includes: an acquisition module for acquiring bus current values ​​and / or sector time intervals; a back electromotive force zero-crossing detection module electrically connected to the main control module, for detecting the zero-crossing point of the back electromotive force of the motor, and outputting a first signal to the main control module according to the zero-crossing point; the main control module is electrically connected to the drive module and the acquisition module, and the main control module includes a signal output module for receiving the first signal and outputting a commutation signal to the drive module; the drive module is used to drive the motor to commutate according to the commutation signal; the main control module also includes an operation comparison module, a storage module and an output module; the operation comparison module is used to receive the bus current value and / or sector time interval and process it to obtain processing information, and the main control module compares the processing information with the preset conditions stored in the storage module; the storage module stores the current threshold and the preset conditions; when the main control module fails to receive the first signal, it determines whether the processing information meets the preset conditions, and when it meets the conditions, the output module outputs the commutation signal.

[0132] The brushless motor commutation system applies the brushless motor commutation control method. The specific determination method is as described in the first to fourth embodiments.

[0133] The present application also provides a commutation control system for a brushless motor, comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, and the above-mentioned method is implemented when the processor executes the computer program.

[0134] The present application also provides a readable medium having a non-volatile program code executable by a processor, wherein the program code enables the processor to execute the above method.

[0135] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or apparatus comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or apparatus comprising the element.

[0136] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A commutation control method for a brushless motor, characterized in that: The method comprises: Step 1: If it is detected that the back electromotive force crosses the zero point and the driving commutation fails, the bus current value and / or the commutation time interval are obtained; Step 2: Acquire processing information according to the bus current value and / or commutation time interval; Step 3: Determine whether the processed information meets the preset conditions. When the preset conditions are met, control the motor to perform forced commutation.

2. The commutation control method of a brushless motor according to claim 1, characterized in that: The processing information includes a bus current slope value, and the step three includes: When the bus current slope value meets the first preset condition, controlling forced commutation; or when the bus current slope value satisfies a second preset condition, controlling forced commutation; The first preset condition is to determine that the bus current slope value changes in accordance with the rules of being greater than zero, approximately equal to zero, and less than zero in sequence; The second preset condition is to determine that the bus current slope value changes in a pattern of being greater than zero, approximately equal to zero, less than zero, and greater than zero, in sequence.

3. The commutation control method of a brushless motor according to claim 1, characterized in that: The processing information includes the bus current difference, and the step three includes: When the bus current difference satisfies a third preset condition, controlling forced commutation; or when the bus current difference satisfies a fourth preset condition, controlling forced commutation; The third preset condition is to judge that the bus current difference changes in a pattern of being greater than zero, approximately equal to zero and less than zero in sequence; the fourth preset condition is to judge that the bus current difference changes in a pattern of being greater than zero, approximately equal to zero, less than zero and greater than zero in sequence.

4. The commutation control method of a brushless motor according to claim 1, characterized in that: The processing information includes the bus current slope value, the bus current instantaneous value and the estimated time commutation value, and the step three includes: When the bus current slope value satisfies a first preset condition, the bus current instantaneous value satisfies a threshold condition, and the estimated time commutation value satisfies a conditional time, controlling forced commutation; or when the bus current slope value satisfies a second preset condition, the bus current instantaneous value satisfies a threshold condition, and the estimated time commutation value satisfies a time condition, controlling forced commutation; The first preset condition is to determine that the bus current slope value changes in accordance with the rules of being greater than zero, approximately equal to zero, and less than zero in sequence; The second preset condition is to determine that the busbar electrical slope difference changes in a pattern of being greater than zero, approximately equal to zero, less than zero, and greater than zero, in sequence.

5. The commutation control method of a brushless motor according to claim 1, characterized in that: The processing information includes the bus current difference, the bus current instantaneous value and the estimated time commutation value, and the step three includes: When the bus current difference satisfies a third preset condition, the bus current instantaneous value satisfies a threshold condition, and the estimated time commutation value satisfies a time condition, controlling forced commutation; or when the bus current difference satisfies a fourth preset condition and the bus current instantaneous value satisfies a threshold condition, and the estimated time commutation value satisfies a time condition, controlling forced commutation; The third preset condition is to determine that the bus current difference changes in a pattern of being greater than zero, approximately equal to zero, and less than zero in sequence; The fourth preset condition is to determine that the bus current difference changes in a pattern of being greater than zero, approximately equal to zero, less than zero, and greater than zero, in sequence.

6. A commutation control system for a brushless motor, characterized in that: It includes detection module, acquisition module, processing module and judgment module. The detection module is used to detect the zero-crossing point of the back electromotive force to drive commutation; The acquisition module is used to collect bus current value and / or commutation time interval when the detection module fails; The processing module is used to process the bus current value and / or the commutation time interval to obtain processing information; The judging module is used to judge whether the processing information meets a preset condition, and when the preset condition is met, the motor is controlled to perform forced commutation.

7. A commutation control system for a brushless motor, characterized in that: include: A collection module, used for collecting bus current values ​​and / or sector time intervals; The back electromotive force zero-crossing detection module is electrically connected to the main control module, and is used to detect the back electromotive force zero-crossing point of the motor, and output a first signal to the main control module according to the zero-crossing point; The main control module is electrically connected to the driving module and the acquisition module, and the main control module includes a signal output module for receiving the first signal and outputting a commutation signal to the driving module; The driving module is used to drive the motor to commutate according to the commutation signal; The main control module also includes an operation comparison module, a storage module and an output module; The operation comparison module is used to receive the bus current value and / or the sector time interval and process them to obtain processing information, and the main control module compares the processing information with the preset conditions stored in the storage module; The storage module stores the current threshold and the preset condition; When the main control module fails to receive the first signal, it determines whether the processing information meets a preset condition. If so, the output module outputs a commutation signal.

8. A commutation control system for a brushless motor as claimed in claim 7, characterized in that: The processed information includes a bus current slope value, a bus current difference value, a bus current instantaneous value and / or an estimated time commutation value.

9. A commutation control system for a brushless motor, comprising a memory and a processor, wherein the memory stores a computer program that can be run on the processor, characterized in that: When the processor executes the computer program, the method according to claims 1 to 5 is implemented.

10. A readable medium having a non-volatile program code executable by a processor, characterized in that: The program code causes the processor to execute the method of claims 1-5.

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