Brushless Motor Rotor Detection Device, Determination and Calculation Method, and Fitness Tensile Device

Abstract

The present invention discloses a brushless motor rotor detection device, a determination and calculation method, and a fitness tensioner, belonging to the technical field of motor equipment. A method for detecting the position of a motor rotor according to the present invention includes the following steps: obtaining the voltage offset value of a sensor based on the maximum and minimum values of the voltage detected by the sensor and the voltage standard value; calculating the scaling coefficient of the sensor by using the voltage offset value and the electrical cycle value; calculating the electrical angle increment through the scaling coefficient and the amplitude value detected by the sensor; adding the electrical angle increment to the starting value of the partition to obtain the relative electrical angle; and obtaining the absolute electrical angle according to the relative electrical angle and the initial offset angle of the rotor, so as to realize the detection of the position of the motor rotor. By introducing the scaling coefficient, the present invention reduces the calculation error and makes the detection method feasible. At the same time, by calculating the voltage offset value, the electrical angle increment, the relative electrical angle, and the absolute electrical angle, the accurate detection of the position of the motor rotor is realized.

Description

Technical Field

[0001] The present invention relates to a brushless motor rotor detection device, a determination and calculation method, and a fitness puller, belonging to the technical field of motor equipment. Background Art

[0002] For a permanent magnet brushless DC motor (BLDC) to use FOC control, accurate rotor angle information needs to be obtained. Traditional methods include the sensorless method using back electromotive force detection, the sensor method using multiple switch Hall sensors, or the sensor method using a magnetic encoder. However, these methods all have obvious disadvantages. The sensorless method has a large interference because it needs to detect the back electromotive force of each phase during the rotation of the motor. The calculated angle information has a large error and the algorithm has a high complexity, making it impossible to achieve stable control at low speeds. The method using switch Hall sensors only obtains discrete angle information within a rotation period, and the electrical angle needs to be estimated, with a large error and also unable to achieve stable control at low speeds. The method using a magnetic encoder can provide accurate angle information, but it requires a dedicated magnet to be installed on the rotor shaft for cooperation in detection, has high requirements for the structure and high cost, and can only be applied to a few scenarios. Summary of the Invention

[0003] Aiming at the defects of the prior art, the first object of the present invention is to provide a motor rotor position detection method that fully considers the relationship between the voltage value detected by the sensor and the electrical angle, reduces the calculation error by introducing a scaling coefficient, and makes the detection method feasible; at the same time, by calculating the voltage offset value, electrical angle increment, relative electrical angle, and absolute electrical angle, the accurate detection of the motor rotor position is realized.

[0004] The second object of the present invention is to provide an outer rotor permanent magnet brushless motor rotor position detection device that can accurately detect the motor rotor position through two sensors, is easy to assemble, can effectively improve the assembly efficiency, reduce the manufacturing cost, has a clever concept, and has a high detection accuracy.

[0005] The third object of the present invention is to provide a method for determining the installation position of sensors that determines the axial position and radial position of the motor rotor magnet, and finally determines the relative angle of the two sensors on the equidistant circle, so that the measured electrical angle error can be controlled within ±5°, meeting the requirements of the electrical angle information required for the stable operation of the motor at low speeds.

[0006] The fourth object of the present invention is to provide a fitness puller that can accurately detect the motor rotor position through two sensors, has a simple installation, can effectively improve the assembly efficiency, reduce the manufacturing cost, and has a high detection accuracy.

[0007] To achieve the first object above, the first technical solution of the present invention is as follows:

[0008] A method for detecting the position of an electric motor rotor,

[0009] comprises the following steps:

[0010] Numerically process the electrical angle of the rotor to form an electrical cycle, and partition the electrical cycle according to the number of sensors;

[0011] Obtain the voltage offset value of the sensor according to the maximum and minimum voltage values detected by the sensor and the voltage standard value;

[0012] Calculate the scaling coefficient of the sensor by using the voltage offset value and the electrical cycle value;

[0013] Calculate the electrical angle increment through the scaling coefficient and the amplitude detected by the sensor;

[0014] Add the electrical angle increment to the starting value of the partition to obtain the relative electrical angle;

[0015] Obtain the absolute electrical angle according to the relative electrical angle and the initial offset angle of the rotor,

[0016] Realize the detection of the position of the electric motor rotor.

[0017] Through continuous exploration and experiments, the present invention fully considers that the voltage values detected by the sensors and the electrical angles are not in one-to-one correspondence, and at the same time, the installation errors will cause different measurement ranges of the sensors. Therefore, a scaling coefficient is introduced to reduce the calculation error and make the detection method feasible. At the same time, by calculating the voltage offset value, electrical angle increment, relative electrical angle and absolute electrical angle, the accurate detection of the position of the electric motor rotor is realized.

[0018] Further, for the convenience of program calculation, the present invention numerically processes the electrical angle of the rotor, and represents the angle values from 0° to 360° with an integer range. For example, 0 - 1023 can be used to represent 0° to 360°, and in actual applications, any value can be taken, such as 0 - 32767.

[0019] Furthermore, since the relative electrical angle is only a change value calculated by the sensor and does not coincide with the actual electrical angle of the motor, the present invention combines the relative electrical angle and the offset angle calibrated during initialization for calculation, so that the calculated absolute electrical angle coincides with the actual value, and finally completes the detection of the position of the electric motor rotor. The solution is detailed, practical and easy to implement.

[0020] Still further, by applying the present invention, the measured electrical angle error can be controlled within ±5°, which is sufficient to meet the requirements of the electrical angle information required for the stable operation of the motor at low speed.

[0021] Compared with the non-sensing detection method, the present invention has the advantages of simple algorithm and high precision. Compared with the switch Hall detection method, the present invention has the advantages of high precision and simple installation. Compared with the magnetic encoder method, the present invention has the advantages of simple installation, low cost, no need for additional magnets, and no space restrictions.

[0022] As the preferred technical measures:

[0023] The sensor is a linear Hall sensor, and there are two of them, including sensor 1 and sensor 2, which can divide the electrical cycle into four equal areas, including area 1, area 2, area 3, and area 4;

[0024] The corresponding method of sensor 1, sensor 2 and two linear Hall sensors is as follows:

[0025] The linear Hall sensor with leading phase in the rotation direction is sensor one, and the linear Hall sensor with lagging phase in the rotation direction is sensor two.

[0026] The present invention can detect the position of the motor rotor through two sensors, is easy to assemble, can effectively improve assembly efficiency, and reduce manufacturing costs, and has an ingenious design.

[0027] As the preferred technical measures:

[0028] The electrical angle is 0 to 360 degrees or -180 to 180 degrees;

[0029] The electrical cycle is 0-N;

[0030] N is a positive integer, which is greater than 360, for ease of processing by computer programs.

[0031] As the preferred technical measures:

[0032] The voltage standard value is the median value, and its calculation method is as follows:

[0033] The motor rotor is rotated to record the maximum and minimum values ​​of each pair of magnets collected by the two linear Hall sensors, and the maximum and minimum values ​​are averaged to obtain the maximum value mean and the minimum value mean;

[0034] The mean of the maximum value and the mean of the minimum value are taken as the initial value of the rotor position;

[0035] The maximum value mean and the minimum value mean are averaged to get the mean value, which is used as the median value of the sensor.

[0036] As the preferred technical measures:

[0037] The voltage offset value is calculated as follows:

[0038] According to the voltage values detected by Sensor 1 and Sensor 2, the voltage values detected by the sensors are located and partitioned;

[0039] When the sensor is located in Area 1, the mean value of the maximum voltage detected by Sensor 1 is subtracted from the median value to obtain the first offset value; at the same time, the median value of Sensor 2 is subtracted from the mean value of the minimum voltage it detects to obtain the second offset value;

[0040] When the sensor is located in Area 2, the mean value of the maximum voltage of Sensor 1 is subtracted from the median value to obtain the first offset value; at the same time, the mean value of the maximum voltage of Sensor 2 is subtracted from the median value to obtain the second offset value;

[0041] When the sensor is located in Area 3, the median value of Sensor 1 is subtracted from the mean value of its minimum voltage to obtain the first offset value; at the same time, the mean value of the maximum voltage of Sensor 2 is subtracted from the median value to obtain the second offset value;

[0042] When the sensor is located in Area 4, the median value of Sensor 1 is subtracted from the mean value of its minimum voltage to obtain the first offset value; at the same time, the median value of Sensor 2 is subtracted from the mean value of its minimum voltage to obtain the second offset value;

[0043] For the above-mentioned location partitioning, the voltage value collected by the sensor is compared with the median value to determine the area where the voltage value detected by the sensor is located. The specific method is as follows:

[0044] When the voltage value detected by Sensor 1 is greater than the median value and the voltage value detected by Sensor 2 is less than the median value, it is Area 1;

[0045] When the voltage values detected by both sensors are greater than the median value, it is Area 2;

[0046] When the voltage value detected by Sensor 1 is less than the median value and the voltage value detected by Sensor 2 is greater than the median value, it is Area 3;

[0047] When the voltage values detected by both sensors are less than the median value, it is Area 4;

[0048] The calculation method of the scaling coefficient is as follows:

[0049] The voltage offset value is divided by the electrical cycle and multiplied by the number of partitions to obtain the scaling coefficient of the sensor in a certain area.

[0050] As a preferred technical measure:

[0051] The calculation method of the amplitude detected by the sensor is as follows:

[0052] The difference is calculated between the current value detected by the sensor and the previous inflection point value, and the inflection point values include the median value and the maximum and minimum values;

[0053] When in Area 1, the detection amplitude of Sensor 1 is equal to the current value detected by Sensor 1 minus the median value of Sensor 1,

[0054] The detected amplitude of Sensor 2 is equal to the current value detected by Sensor 2 minus the minimum value of Sensor 2;

[0055] When in Region 2, the detected amplitude of Sensor 1 is equal to the maximum value of Sensor 1 minus the current value detected by Sensor 1,

[0056] The detected amplitude of Sensor 2 is equal to the current value detected by Sensor 2 minus the median value of Sensor 2;

[0057] When in Region 3, the detected amplitude of Sensor 1 is equal to the median value of Sensor 1 minus the current value detected by Sensor 1,

[0058] The detected amplitude of Sensor 2 is equal to the maximum value of Sensor 2 minus the current value detected by Sensor 2;

[0059] When in Region 4, the detected amplitude of Sensor 1 is equal to the current value detected by Sensor 1 minus the minimum value of Sensor 1,

[0060] The detected amplitude of Sensor 2 is equal to the current value detected by Sensor 2 minus the median value of Sensor 2.

[0061] As a preferred technical measure:

[0062] The calculation method of the electrical angle increment is as follows:

[0063] After dividing the detected amplitudes of the two sensors by the corresponding scaling factors respectively, and then performing an averaging process to obtain the electrical angle increment of a certain region;

[0064] The calculation method of the relative electrical angle is as follows:

[0065] According to the region where the electrical angle increment is located, obtain the starting value of the partition of this region;

[0066] Add the starting value of the partition and the electrical angle increment to obtain the relative electrical angle;

[0067] The starting value of the partition is the minimum value of a certain region;

[0068] For example, in the range of 0 - 1023, the starting value of the partition for Region 1 is 0, the starting value of the partition for Region 2 is 256, the starting value of the partition for Region 3 is 512, and the starting value of the partition for Region 4 is 768.

[0069] The calculation method of the initial rotor offset angle is as follows:

[0070] Use field-oriented control for the motor, with the q-axis torque being zero and the d-axis torque being 20% of the maximum torque. At this time, the actual electrical angle is zero, calculate the offset electrical angle value, and record this offset electrical angle value as the initial rotor offset angle;

[0071] The calculation method of the absolute electrical angle is as follows:

[0072] Subtract the rotor initial offset angle from the relative electrical angle to obtain the absolute electrical angle, which can be used in the FOC control algorithm.

[0073] To achieve one of the above purposes, the second technical solution of the present invention is:

[0074] A method for detecting the rotor position of an outer-rotor permanent magnet brushless DC motor, including constructing a sensor position determination model, an initialization parameter configuration model, and a motor rotor position calculation model;

[0075] The sensor position determination model obtains the positions of two sensors on the motor rotor magnets by calculating the axial position, radial position of the motor rotor magnets, and the relative angle between the two sensors;

[0076] The initialization parameter configuration model includes the following:

[0077] Rotate the motor rotor, and record the maximum and minimum values of each pair of magnets collected by two linear Hall sensors respectively. Average the maximum and minimum values respectively to obtain the maximum value average and the minimum value average;

[0078] Use the maximum value average and the minimum value average as the initial maximum and minimum values in the motor rotor position calculation model;

[0079] Average the maximum value average and the minimum value average to obtain an average value as the median of the sensor;

[0080] And use field-oriented control for the motor, with the q-axis torque being zero and the d-axis torque being 20% of the maximum torque. At this time, the actual electrical angle is zero, calculate the offset electrical angle value, and record this offset electrical angle value as the rotor initial offset angle;

[0081] The construction method of the motor rotor position calculation model is as follows:

[0082] First step, install two sensors on the motor rotor and number the two sensors, which are sensor one and sensor two;

[0083] At the same time, numerically process the electrical angle of the rotor to form an electrical cycle, and equally divide the electrical cycle into four zones, and the four zones include zone one, zone two, zone three, and zone four;

[0084] Second step, compare the voltage value collected by the sensor with the median value to perform positioning and zoning, and this positioning and zoning corresponds to a certain zone in the first step;

[0085] The positioning and zoning includes the following:

[0086] When the voltage value detected by Sensor 1 is greater than the median value and the voltage value detected by Sensor 2 is less than the median value, it is Region 1;

[0087] When the voltage values detected by both sensors are greater than the median value, it is Region 2;

[0088] When the voltage value detected by Sensor 1 is less than the median value and the voltage value detected by Sensor 2 is greater than the median value, it is Region 3;

[0089] When the voltage values detected by both sensors are less than the median value, it is Region 4;

[0090] In the third step, according to the positioning partitions in the second step, calculate the data scaling coefficients for each positioning partition. The offset value is obtained by subtracting the median value from the average of the maximum voltage values of the sensors. Divide the offset value by one-fourth of the electrical cycle value to obtain the scaling coefficient of the sensor in a certain region;

[0091] In the fourth step, subtract the current value detected by the sensor from the previous inflection point value. The inflection point values include the median value and the extreme values to obtain the amplitude of the sensor;

[0092] In the fifth step, divide the amplitude of the sensor obtained in the fourth step by the scaling coefficient in the third step and then perform an averaging process to obtain the electrical angle increment of a certain region;

[0093] In the sixth step, according to the region where the electrical angle increment in the fifth step is located, obtain the starting value of the partition for this region;

[0094] Add the starting value of the partition to the electrical angle increment to obtain the relative electrical angle;

[0095] In the seventh step, subtract the initial rotor offset angle from the relative electrical angle in the sixth step to obtain the absolute electrical angle, realizing the detection of the rotor position of the outer rotor permanent magnet brushless DC motor.

[0096] Through continuous exploration and experiments, the present invention fully considers that the voltage values detected by the sensors and the electrical angles are not in one-to-one correspondence, and at the same time, installation errors will cause different measurement ranges of the sensors. Therefore, a scaling coefficient is introduced to reduce calculation errors and make the detection method feasible. At the same time, by calculating the voltage offset value, electrical angle increment, relative electrical angle, and absolute electrical angle, accurate detection of the motor rotor position is realized.

[0097] Furthermore, since the relative electrical angle is only a calculated change value by the sensors and does not coincide with the actual electrical angle of the motor, the present invention combines the relative electrical angle and the initialized and calibrated offset angle to participate in the calculation, making the calculated absolute electrical angle coincide with the actual value, and finally completing the detection of the motor rotor position. The solution is detailed, practical, and easy to implement.

[0098] Furthermore, by applying the present invention, the measured electrical angle error can be controlled within ±5°, which is sufficient to meet the requirements of the electrical angle information needed for the stable low-speed operation of the motor.

[0099] Moreover, compared with the sensorless detection method, the present invention has the advantages of simple algorithm and high precision. Compared with the switch Hall detection method, the present invention has the advantages of high precision and simple installation. Compared with the magnetic encoder method, the present invention has the advantages of simple installation, low cost, no need for additional magnets, and no space limitation.

[0100] To achieve one of the above purposes, the third technical solution of the present invention is:

[0101] An outer rotor permanent magnet brushless motor rotor position detection device, applying one of the above motor rotor position detection methods and / or one of the above outer rotor permanent magnet brushless DC motor rotor position detection methods;

[0102] It includes a detection circuit board and two linear Hall sensors mounted thereon;

[0103] The plane where the linear Hall sensors are located is perpendicular to the axis line of the motor rotor, and the linear Hall sensors are located below the motor rotor magnets.

[0104] The present invention can accurately detect the motor rotor position through two sensors, which is convenient for assembly, can effectively improve the assembly efficiency, reduce the manufacturing cost, has a clever concept, low cost, simple installation and high detection accuracy.

[0105] To achieve one of the above purposes, the fourth technical solution of the present invention is:

[0106] A method for determining the installation position of sensors,

[0107] which is applicable to the above outer rotor permanent magnet brushless motor rotor position detection device;

[0108] Determining the installation position of the sensors on the motor rotor magnets includes determining the axial position of the motor rotor magnets, determining the radial position of the motor rotor magnets, and determining the relative angle of the two sensors on the equidistant circle;

[0109] The axial position of the motor rotor magnets is determined according to the magnetic field strength of the motor rotor magnets and the range of the linear Hall sensors;

[0110] The vertical distance from the surface of the sensor to the bottom surface of the motor rotor magnet is generally between 1 mm and 5 mm;

[0111] The method for determining the radial position of the motor rotor magnets specifically includes the following content:

[0112] First, draw the position circle where the motor rotor magnets are located, and then draw equally spaced circles inward in the radial direction. The diameter of the equally spaced circles is determined by the magnetic field strength of the motor rotor magnets and the sensor range, generally between 1 mm and 5 mm. The sensors are placed on these equally spaced circles;

[0113] The relative angle between the two sensors on the equally spaced circle is determined by the number of pole pairs, which specifically includes the following:

[0114] First, calculate the angle of the electrical period in the mechanical period according to the number of pole pairs, that is, divide 360° by the number of pole pairs;

[0115] When the number of pole pairs of the motor is 7, the mechanical angle occupied by the electrical period is 51.4°;

[0116] Then calculate the mechanical angle corresponding to an electrical angle of 90°, and its value is 12.9°;

[0117] Finally, take the mechanical angle corresponding to an electrical angle of 450° as the relative angle between the two sensors on the equally spaced circle, and the relative angle is 64.3°;

[0118] When the number of pole pairs of the motor is less than or equal to 2, select the mechanical angle corresponding to an electrical angle of 90° as the relative angle detected by the two sensors;

[0119] After determining the sensor positions, install and fix the corresponding circuit board on the motor by drawing.

[0120] The present invention first determines the axial position of the motor rotor magnets, then determines the radial position of the motor rotor magnets, and finally determines the relative angle between the two sensors on the equally spaced circle. The solution is detailed, feasible, and easy to implement.

[0121] The measured electrical angle error obtained by the present invention can be controlled within ±5°, which is sufficient to meet the requirements of the electrical angle information required for the stable operation of the motor at low speed.

[0122] To achieve one of the above purposes, the fifth technical solution of the present invention is:

[0123] A fitness tensioner is provided with an outer rotor permanent magnet brushless motor.

[0124] The outer rotor permanent magnet brushless motor includes a stator, a rotor, and the outer rotor permanent magnet brushless motor rotor position detection device as described above;

[0125] And according to the method for determining the installation position of a sensor as described above, determine the assembly positions of two linear Hall sensors on the rotor;

[0126] At the same time, apply the above-mentioned method for detecting the rotor position of a motor or / and the above-mentioned method for detecting the rotor position of an outer rotor permanent magnet brushless DC motor to detect the rotor position.

[0127] The fitness tensioner of the present invention can accurately detect the position of the motor rotor through two sensors. It has a simple installation, can effectively improve the assembly efficiency, reduce the manufacturing cost, and has a relatively high detection accuracy. The measured electrical angle error can be controlled within ±5°, which is particularly suitable for fitness equipment such as fitness tensioners that require low-speed and stable operation.

[0128] Compared with the prior art, the present invention has the following beneficial effects:

[0129] Through continuous exploration and experiments, the present invention fully considers that the voltage values detected by the sensors and the electrical angles do not correspond one by one, and at the same time, the installation errors will lead to different measurement ranges of the sensors. Therefore, a scaling coefficient is introduced to reduce the calculation error and make the detection method feasible. At the same time, by calculating the voltage offset value, electrical angle increment, relative electrical angle, and absolute electrical angle, the accurate detection of the motor rotor position is realized.

[0130] Furthermore, for the convenience of program calculation, the present invention numerically processes the electrical angle of the rotor, representing the angle values from 0° to 360° with a range of integers. For example, 0 - 1023 can be used to represent 0° to 360°, and in actual applications, any value can be taken, such as 0 - 32767.

[0131] Moreover, since the relative electrical angle is only a change value calculated by the sensor and does not coincide with the actual electrical angle of the motor, the present invention combines the relative electrical angle and the offset angle of the initial calibration to participate in the calculation, so that the calculated absolute electrical angle coincides with the actual value, and finally the detection of the motor rotor position is completed. The solution is detailed, feasible, and easy to implement.

[0132] Furthermore, by applying the present invention, the measured electrical angle error can be controlled within ±5°, which is sufficient to meet the requirements of the electrical angle information required for the low-speed and stable operation of the motor.

[0133] Compared with the sensorless detection method, the present invention has the advantages of simple algorithm and high accuracy. Compared with the switch Hall detection method, the present invention has the advantages of high accuracy and simple installation. Compared with the magnetic encoder method, the present invention has the advantages of simple installation, low cost, no need for additional magnets, and no space limitation. BRIEF DESCRIPTION OF THE DRAWINGS

[0134] Figure 1 It is a structural diagram of the rotor position detection device of the external rotor permanent magnet brushless motor of the present invention applied to the motor;

[0135] Figure 2 is Figure 1 a diagram showing a certain angle conversion of the shown structure;

[0136] Figure 3This is a schematic diagram of the electrical cycle of the present invention.

[0137] Description of the reference numerals in the drawings:

[0138] 1. Stator; 2. Rotor; 3. Permanent magnet; 4. Linear Hall sensor; 5. Circuit board. Detailed implementation manners

[0139] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0140] On the contrary, the present invention covers any alternatives, modifications, equivalent methods and solutions made within the spirit and scope of the present invention defined by the claims. Further, in order to enable the public to better understand the present invention, some specific details are described in detail in the following detailed description of the present invention. Those skilled in the art can fully understand the present invention without the description of these details.

[0141] It should be noted that when two elements are "fixedly connected", the two elements can be directly connected or there can also be intermediate elements. On the contrary, when an element is referred to as being "directly on" another element, there is no intermediate element.

[0142] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field to which the present invention belongs. The terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "or / and" used herein includes any and all combinations of one or more of the related listed items.

[0143] As Figure 1-2 shown, a specific embodiment of the present invention applied to an outer rotor permanent magnet brushless DC motor:

[0144] An outer rotor permanent magnet brushless motor rotor position detection device includes a detection circuit board 5 and two linear Hall sensors mounted thereon. The outer rotor permanent magnet brushless DC motor includes a motor rotor 2 and a motor stator 1. There are specific requirements for the installation positions of the linear Hall sensors. First, the plane where the linear Hall sensors are located is perpendicular to the axis of the motor rotor 2, and the linear Hall sensors are located below the permanent magnets 3 of the rotor 2. The specific positions are determined through the following steps:

[0145] S1. Determine the axial position of the permanent magnet 3. It is determined by the magnetic field strength of the permanent magnet 3 and the range of the linear Hall sensor. The vertical distance from the surface of the sensor to the bottom surface of the permanent magnet 3 of the rotor 2 is generally between 1 mm and 5 mm.

[0146] S2. Determine the radial position of the permanent magnet 3. First, draw the position circle where the permanent magnet 3 is located, and then draw equidistant circles inward in the radial direction. The equidistant distance is determined by the magnetic field strength of the permanent magnet 3 and the sensor range, generally between 1 mm and 5 mm. The sensor is placed on this equidistant circle.

[0147] S3. Determine the relative angle of the two sensors on the equidistant circle. It is determined by the number of pole pairs. First, calculate the angle occupied by the electrical period in the mechanical period according to the number of pole pairs, that is, divide 360° by the number of pole pairs. For example, if the number of pole pairs of the motor in the figure is 7, then the mechanical angle occupied by the electrical period can be obtained as 51.4°. Then calculate the mechanical angle occupied by the electrical angle of 90°. In this example, it is 12.9°. Finally, use the mechanical angle occupied by the electrical angle of 450° as the relative angle of the two sensors on the equidistant circle. In this example, it is 64.3°. Specifically, if the number of pole pairs of the motor is less than or equal to 2, then select the mechanical angle occupied by the electrical angle of 90° as the relative angle of the two sensors.

[0148] S4. After determining the sensor position, install and fix the corresponding circuit board 5 on the motor by drawing.

[0149] A specific embodiment of the rotor position detection method for the outer rotor permanent magnet brushless DC motor of the present invention:

[0150] A rotor position detection method for an outer rotor permanent magnet brushless DC motor includes an initialization parameter configuration model and a motor rotor 2 position calculation model. Both of these models need to be used in conjunction with the installation method of the above linear Hall. Among them, the initialization parameter configuration model is used for initialization configuration when the new motor structure is just finalized in the initial stage of research and development. As long as the mechanical structure remains unchanged during subsequent mass production, there is no need to reconfigure or calibrate. The motor rotor 2 position calculation model calculates the position in real time during the operation of the motor and converts it into electrical angle information for use by the FOC motor control algorithm.

[0151] The steps of the initialization parameter configuration model are as follows:

[0152] Step 1, manually rotate the motor rotor 2, and record the maximum and minimum values of each pair of permanent magnets 3 collected by the two linear Hall sensors respectively. Average the maximum and minimum values respectively to obtain the maximum value average and the minimum value average. This value is used as the initial maximum and minimum values in the rotor 2 position calculation algorithm.

[0153] Step 2, average the two values in the previous step to obtain the average value and use it as the median of the sensor.

[0154] Step 3: Use FOC to control the torque of the q-axis of the motor to zero and the torque of the d-axis to 20% of the maximum torque. At this time, the actual electrical angle is zero. Run the relative electrical angle values calculated in the first 7 steps of the motor rotor position calculation model and record this electrical angle value as the offset angle value. If the motor structure remains unchanged, this offset angle value does not need to be reconfigured, that is, it does not need to be recalibrated.

[0155] The steps of the motor rotor position calculation model are as follows:

[0156] Step 1: Numeralize the electrical angle

[0157] Represent the entire electrical cycle numerically, for example, 0 - 1023, representing the electrical angle from -180° to 180°.

[0158] Step 2: Divide the electrical cycle

[0159] Divide the electrical cycle into four equal regions. For example, 0 - 255 is Region 1, 256 - 511 is Region 2, 512 - 767 is Region 3, and 768 - 1023 is Region 4.

[0160] Step 3: Number the sensors

[0161] Number the two linear Hall sensors as Sensor 1 and Sensor 2 respectively. The one with a phase lead in the rotation direction is Sensor 1, and the lagging one is Sensor 2. As shown in the figure, the yellow line is Sensor 1 and the blue line is Sensor 2. When reversing, the blue line will be ahead of the yellow line, and then the numbers are exchanged at this time.

[0162] Step 4: Locate the region

[0163] Compare the voltage values collected by the sensors with the median value. When the value of Sensor 1 is greater than the median value and the value of Sensor 2 is less than the median value, it is Region 1. When both values are greater than the median value, it is Region 2. When the value of Sensor 1 is less than the median value and the value of Sensor 2 is greater than the median value, it is Region 3. When both are less than the median value, it is Region 4. Correlate this region division with the division in Step 2.

[0164] The so-called "correlation" means that the increment calculated in which region represents the electrical angle change in that region. For example (the electrical angle cycle is still represented by 0 - 1024), the sensor values collected at a certain moment are located in Region 2 through location division, and the increment calculated through the amplitude in Region 2 is 100. Corresponding to the electrical angle division, it means that on the basis of the value 256, 100 is added, that is, the current electrical angle value is 356, and when converted to 0° to 360°, it is 125.16°.

[0165] Step 5: Calculate the scaling factor

[0166] Calculate the data scaling factor for each partition according to the partition. For example, if it is in Region 1, subtract the median from the average of the maximum voltages detected by Sensor 1 to obtain the offset value, and divide the offset value by one-fourth of the electrical cycle value to obtain the scaling factor of Sensor 1 in Region 1. Similarly, use the average of the minimum voltages detected by Sensor 2 and the median to obtain the scaling factor of Sensor 2 in Region 1. If it is in Region 2, the maximum and median values of Sensor 1 and the maximum and median values of Sensor 2 need to be used for calculation. Similarly, the scaling factors of the 2 sensors in each region can be obtained.

[0167] Step 6, calculate the detected amplitude

[0168] The method for calculating the detected amplitude is to subtract the previous inflection point value from the current value, and the inflection point values include the median and the extreme values. In Region 1, the detected amplitude of Sensor 1 is equal to the sensor value minus the median, and the detected amplitude of Sensor 2 is equal to the current value minus the minimum value. In Region 2, the detected amplitude of Sensor 1 is equal to the maximum value minus the current value, and the detected amplitude of Sensor 2 is equal to the current value minus the median. In Region 3, the detected amplitude of Sensor 1 is equal to the median minus the current value, and the detected amplitude of Sensor 2 is equal to the maximum value minus the current value. In Region 4, the detected amplitude of Sensor 1 is equal to the current value minus the minimum value, and the detected amplitude of Sensor 2 is equal to the current value minus the median.

[0169] Step 7, calculate the relative electrical angle

[0170] Divide the amplitudes of the two sensors obtained in the previous step by the scaling factor and then perform an averaging process to obtain the electrical angle increment of this region. Add the increment to the starting value of the partition according to the region where it is located to obtain the relative electrical angle. The starting value of the partition is the minimum value in the partition range in Step 2. For example, in the range of 0 - 1023, the starting value of Region 1 is 0, the starting value of Region 2 is 256, the starting value of Region 3 is 512, and the starting value of Region 4 is 768.

[0171] Step 8, calculate the absolute electrical angle

[0172] Subtract the bias angle in the initialization parameter configuration model from the relative electrical angle to obtain the absolute electrical angle, and this angle can be used in the FOC control algorithm.

[0173] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0174] This application is described with reference to the flowcharts and / or block diagrams of methods, apparatuses (systems), and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowchart and / or block diagram, as well as the combination of flows and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to the processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing devices to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing devices generate means for implementing the functions specified in one or more of the flows Figure 1 one or more of the flows and / or blocks Figure 1 or a means for implementing the functions specified in one or more of the blocks.

[0175] In the present application, the fixed connection method can be screw connection, welding, riveting, plugging, or connection through a third component, and those skilled in the art can select according to the actual situation.

[0176] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications or equivalent replacements can still be made to the specific embodiments of the present invention, and any modification or equivalent replacement that does not depart from the spirit and scope of the present invention should be covered by the protection scope of the claims of the present invention.

Claims

1. A method for detecting the rotor position of an outer-rotor permanent magnet brushless DC motor, characterized in that, Including constructing a sensor position determination model, initializing a parameter configuration model, and an electric motor rotor position calculation model; The sensor position determination model obtains the positions of two sensors on the electric motor rotor magnet by calculating the axial position, radial position of the electric motor rotor magnet, and the relative angle between the two sensors; The initialization parameter configuration model includes the following: Rotate the electric motor rotor, and record the maximum and minimum values of each pair of magnets collected by the two linear Hall sensors respectively. Perform average processing on the maximum and minimum values respectively to obtain the maximum value average and the minimum value average; Use the maximum value average and the minimum value average as the initial maximum and minimum values in the electric motor rotor position calculation model; And perform average processing on the maximum value average and the minimum value average to obtain an average value, which is used as the median of the sensor; And use field-oriented control for the electric motor, with the q-axis torque being zero and the d-axis torque being 20% of the maximum torque, calculate the offset electrical angle value, and record this offset electrical angle value as the initial rotor offset angle; The construction method of the electric motor rotor position calculation model is as follows: In the first step, install the two sensors on the electric motor rotor, and number the two sensors, which are sensor one and sensor two; At the same time, numerically process the electrical angle of the rotor to form an electrical cycle, and equally divide the electrical cycle into four regions, and the four regions include region one, region two, region three, and region four; In the second step, compare the voltage value collected by the sensor with the median to perform positioning and zoning, and this positioning and zoning corresponds to a certain region in the first step; The positioning and zoning includes the following: When the voltage value detected by sensor one is greater than the median and the voltage value detected by sensor two is less than the median, it is region one; When the voltage values detected by both sensors are greater than the median, it is region two; When the voltage value detected by sensor one is less than the median and the voltage value detected by sensor two is greater than the median, it is region three; When the voltage values detected by both sensors are less than the median, it is region four; In the third step, calculate the data scaling factor under this positioning and zoning according to the positioning and zoning in the second step, that is, obtain the voltage offset value of the sensor through the maximum and minimum voltage values detected by the sensor and the median of the voltage, and divide the offset value by one-fourth of the electrical cycle value to obtain the scaling factor of the sensor in a certain region; In the fourth step, subtract the current value detected by the sensor from the previous inflection point value, and the inflection point value includes the median and the maximum and minimum values, to obtain the amplitude of the sensor; In the fifth step, divide the sensor amplitude obtained in the fourth step by the scaling factor in the third step and then perform average processing to obtain the electrical angle increment of a certain region; In the sixth step, according to the region where the electrical angle increment in the fifth step is located, obtain the starting value of the region; Add the starting value of the region to the electrical angle increment to obtain the relative electrical angle; In the seventh step, subtract the initial rotor offset angle from the relative electrical angle in the sixth step to obtain the absolute electrical angle, realizing the detection of the electric motor rotor position of the outer rotor permanent magnet brushless DC motor.

2. The method for detecting the rotor position of an outer-rotor permanent magnet brushless DC motor according to claim 1, characterized in that, The corresponding method between sensor one, sensor two and the two linear Hall sensors is as follows: The linear Hall sensor that is phase advanced in the rotation direction is sensor one, and the lagging linear Hall sensor is sensor two.

3. The method for detecting the rotor position of an outer-rotor permanent magnet brushless DC motor according to claim 1, characterized in that, The electrical angle is 0 degrees to 360 degrees or -180 degrees to 180 degrees; The electrical period is from 0 to N; The N is a positive integer, and N > 360.

4. The method for detecting the rotor position of an outer-rotor permanent magnet brushless DC motor according to claim 3, characterized in that, The calculation method of the voltage offset value is as follows: According to the voltage values detected by Sensor 1 and Sensor 2, the voltage values detected by the sensors are positioned and partitioned; When the sensor is positioned in Region 1, the first offset value is obtained by subtracting the median from the average value of the maximum voltage values detected by Sensor 1; at the same time, the second offset value is obtained by subtracting the average value of the minimum voltage values detected by Sensor 2 from the median of Sensor 2; When the sensor is positioned in Region 2, the first offset value is obtained by subtracting the median from the average value of the maximum values of Sensor 1; at the same time, the second offset value is obtained by subtracting the median from the average value of the maximum values of Sensor 2; When the sensor is positioned in Region 3, the first offset value is obtained by subtracting the average value of the minimum values from the median of Sensor 1; at the same time, the second offset value is obtained by subtracting the median from the average value of the maximum values of Sensor 2; When the sensor is positioned in Region 4, the first offset value is obtained by subtracting the average value of the minimum values from the median of Sensor 1; at the same time, the second offset value is obtained by subtracting the average value of the minimum values from the median of Sensor 2.

5. A method for detecting the rotor position of an outer-rotor permanent magnet brushless DC motor according to claim 1, characterized in that, The calculation method of the sensor amplitude is as follows: The difference is calculated between the current value detected by the sensor and the previous inflection point value, and the inflection point values include the median and the maximum and minimum values; When in Region 1, the detected amplitude of Sensor 1 is equal to the current value detected by Sensor 1 minus the median of Sensor 1, The detected amplitude of Sensor 2 is equal to the current value detected by Sensor 2 minus the minimum value of Sensor 2; When in Region 2, the detected amplitude of Sensor 1 is equal to the maximum value of Sensor 1 minus the current value detected by Sensor 1, The detected amplitude of Sensor 2 is equal to the current value detected by Sensor 2 minus the median of Sensor 2; When in Region 3, the detected amplitude of Sensor 1 is equal to the median of Sensor 1 minus the current value detected by Sensor 1, The detected amplitude of Sensor 2 is equal to the maximum value of Sensor 2 minus the current value detected by Sensor 2; When in Region 4, the detected amplitude of Sensor 1 is equal to the current value detected by Sensor 1 minus the minimum value of Sensor 1, The detected amplitude of Sensor 2 is equal to the current value detected by Sensor 2 minus the median of Sensor 2.

6. A method for detecting the rotor position of an outer-rotor permanent magnet brushless DC motor according to claim 1, characterized in that, The calculation method of the electrical angle increment is as follows: The electrical angle increment of a certain region is obtained by dividing the detected amplitudes of the two sensors by the corresponding scaling factors respectively and then performing an averaging process; The calculation method of the relative electrical angle is as follows: According to the region where the electrical angle increment is located, the starting value of the partition of this region is obtained; The starting value of the partition is added to the electrical angle increment to obtain the relative electrical angle; The starting value of the partition is the minimum value of a certain region.

7. A device for detecting the rotor position of an outer-rotor permanent magnet brushless motor, characterized in that, Apply a rotor position detection method for an outer-rotor permanent magnet brushless DC motor as described in any one of claims 1-6; It includes a detection circuit board and two linear Hall sensors mounted thereon; The plane where the linear Hall sensors are located is perpendicular to the axis line of the motor rotor, and the linear Hall sensors are located below the motor rotor magnets.

8. A method for determining the installation position of a sensor, characterized in that, Applicable to the rotor position detection device for an outer-rotor permanent magnet brushless motor as described in claim 7; The determination of the installation positions of the sensors on the motor rotor magnets includes determining the axial position of the motor rotor magnets, determining the radial position of the motor rotor magnets, and determining the relative angle of the two sensors on the equidistant circle; The axial position of the motor rotor permanent magnet is determined according to the magnetic field intensity of the motor rotor permanent magnet and the range of the linear Hall sensor; The method for determining the radial position of the motor rotor permanent magnet specifically includes the following: First, draw the position circle where the motor rotor permanent magnet is located, and then draw equally spaced circles inward in the radial direction. The diameter of the equally spaced circles is determined by the magnetic field intensity of the motor rotor permanent magnet and the sensor range, and the sensors are placed on these equally spaced circles; The relative angle of the two sensors on the equally spaced circle is determined by the number of pole pairs, which specifically includes the following: First, calculate the angle of the electrical period in the mechanical period according to the number of pole pairs, that is, divide 360° by the number of pole pairs; When the number of pole pairs of the motor is 7, the mechanical angle of the electrical period is 51.4°; Then calculate the mechanical angle corresponding to an electrical angle of 90°, and its value is 12.9°; Finally, take the mechanical angle corresponding to an electrical angle of 450° as the relative angle of the two sensors on the equally spaced circle, and the relative angle is 64.3°; When the number of pole pairs of the motor is less than or equal to 2, the mechanical angle corresponding to an electrical angle of 90° is selected as the relative angle of the two sensors; After determining the sensor positions, the corresponding circuit board is drawn and installed and fixed on the motor.

9. A fitness tensioner is provided with an outer rotor permanent magnet brushless motor, characterized in that, The outer rotor permanent magnet brushless motor includes a stator, a rotor, and the outer rotor permanent magnet brushless motor rotor position detection device as described in claim 7; And according to the method for determining the installation position of a sensor described in claim 8, determine the assembly positions of the two linear Hall sensors on the rotor; At the same time, apply the method for detecting the rotor position of an outer rotor permanent magnet brushless DC motor as described in any one of claims 1-6 to detect the rotor position.

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