Three-phase brushless motor electric angle zero calibration method and device under limited rotation angle constraint and readable storage medium thereof

Abstract

The invention provides a three-phase brushless motor electric angle zero calibration method and device under limited rotation angle constraint and a readable storage medium thereof, and belongs to the technical field of three-phase brushless motor control. Aiming at the problem that calibration is inaccurate due to the fact that an existing method depends on high-speed rotation of a motor or the zero position exceeds the range in a limited rotation angle scene, the method comprises the steps that the quadrature-axis voltage is set to be 0 and the direct-axis voltage is set to be a preset negative value in FOC control, so that a rotor is stabilized at the position corresponding to an electrical angle estimated value; after the rotation angle range is determined, the electrical angle estimated value is adjusted to ensure that the rotor is stabilized in the range, and the electrical angle zero position is calculated through a specific relation based on the stabilized feedback value of the angle sensor, the electrical angle estimated value and the number of pole pairs. The method does not need large-range rotation of the motor, is high in calibration precision, is suitable for corner-limited scenes such as robot joints and holders, and is high in reliability.

Description

Technical Field

[0001] The present invention relates to the technical field of three-phase brushless motor control, and in particular to a method, a device and a readable storage medium thereof for calibrating the electrical angle zero position of a three-phase brushless motor under limited rotation angle constraints. Background Art

[0002] With the development of modern control technology, field-oriented control (FOC) has been widely used in three-phase brushless motor control. The premise of FOC control is to accurately calibrate the motor's electrical angle zero position (that is, the position where the north pole of the rotor permanent magnet is aligned with the axis of the stator A-phase winding).

[0003] For example, CN113063345A discloses a method for calibrating the zero-position angle of a motor. Its core approach is to control the three-phase current to align the magnetic field vector with the A-phase axis. After obtaining the position angle, the rotor is rotated by a preset angle (360° / pole pair number). After repeated calculations, the zero position is calculated using the average value. This method relies on the rotor rotating at a specific angle (360° / pole pair number). If the motor's rotation angle range is smaller than this angle, the rotation operation cannot be completed, making it unsuitable for scenarios with limited rotation angles.

[0004] CN115549545A discloses a brushless motor electrical angle identification method. This method applies a micro-current to rotate the rotor to a relative zero position and calculates the absolute zero position based on the d- and q-axis current components. This method requires the rotor to rotate to a relative zero position. If the zero position falls outside the rotation angle range, the rotor may become stuck at the boundary, making it impossible to accurately determine the relative zero position. This method is also unsuitable for scenarios with limited rotation angle constraints.

[0005] It can be seen that the existing electrical angle zero calibration method mainly has the following two problems: First, by increasing the motor speed and using the peak value of the back electromotive force to calibrate the zero position, this method relies on the motor rotating over a large range and is not applicable to scenarios where the motor can only rotate within a limited angle due to structural constraints. Secondly, by connecting high and low voltage levels to the three phases of the motor, the motor is attracted to a certain angle for calibration. However, when the electrical angle zero position is outside the motor's rotation angle range, the motor may stop close to the rotation angle boundary, resulting in a large deviation between the calibrated zero position and the actual zero position, and the accuracy cannot be guaranteed.

[0006] Therefore, under the constraint of limited rotation angle, there is an urgent need for a reliable and accurate three-phase brushless motor electrical angle zero calibration method, device and readable storage medium thereof. Summary of the Invention

[0007] An embodiment of the present invention provides a method, device and readable storage medium for calibrating the electrical angle zero position of a three-phase brushless motor under limited angle constraints. This addresses the problem that the existing technology is either not applicable under limited angle constraints because it relies on high-speed rotation of the motor (such as the back electromotive force method), or the electrical angle zero position may be outside the angle range, causing the motor to be stuck at the boundary, resulting in inaccurate calibration results.

[0008] The core technology of this invention is to set the quadrature axis voltage in FOC control , direct axis voltage , so that the rotor is stable at the same electrical angle as the estimated value Adjust the corresponding position Ensure that the rotor is stable within the rotation angle range, and then based on the formula (p is the number of pole pairs, is the sensor feedback value) to calculate the electrical angle zero position.

[0009] In a first aspect, the present invention provides a method for calibrating the electrical angle zero position of a three-phase brushless motor under a limited rotation angle constraint, the method comprising the following steps: Step 1: For a three-phase brushless motor with angle sensor feedback and a rotation angle limited to a preset range, set the field-oriented control parameters of the three-phase brushless motor, where the quadrature-axis voltage is set to zero and the direct-axis voltage is set to a preset negative value; Step 2: Determine the rotation angle range of the three-phase brushless motor and obtain the maximum and minimum angle values ​​fed back by the angle sensor; Step 3: Rotate the three-phase brushless motor to near the center of the rotation angle range and start it. Set the estimated electrical angle to the initial value and check the angle sensor feedback value after the motor rotor stabilizes. Step 4: If the stabilized angle sensor feedback value is within the rotation angle range, calculate the electrical angle zero position based on the corresponding relationship between the angle sensor feedback value, the estimated electrical angle value, and the number of motor pole pairs. If the angle sensor feedback value after stabilization is at the boundary of the rotation angle range, the electrical angle estimate is adjusted so that the angle sensor feedback value after stabilization of the motor rotor is within the rotation angle range. Then, the electrical angle zero position is calculated based on the correspondence between the adjusted electrical angle estimate, the stabilized angle sensor feedback value, and the number of motor pole pairs. The electrical angle zero position is the angle sensor feedback position corresponding to the center axis of the motor stator A phase winding, and the corresponding relationship is: The electrical angle zero position is equal to the stabilized angle sensor feedback value minus the ratio of the electrical angle estimate to the number of motor pole pairs.

[0010] Furthermore, in step 1, the absolute value of the preset negative value of the direct-axis voltage is a preset voltage value, and the preset voltage value does not exceed 55-60% of the rated voltage of the motor.

[0011] Furthermore, determining the preset voltage value includes: gradually increasing the voltage value from an initial value until the three-phase brushless motor generates a stable torque that can drive the rotor to rotate, and the voltage value does not exceed 57% of the rated voltage of the motor, and taking this voltage value as the preset voltage value.

[0012] Furthermore, in step 3, the initial value of the electrical angle estimation value is zero.

[0013] Furthermore, in step 4, the method of adjusting the estimated electrical angle is: Increase or decrease the estimated electrical angle value so that the angle sensor feedback value moves toward the center of the rotation angle range after the motor rotor stabilizes.

[0014] Furthermore, in step 1, the field-oriented control realizes the mapping of the three-phase stationary coordinate system and the rotor synchronous rotating coordinate system through Clark-Park transformation and inverse transformation, where the direct axis is the magnetic field direction of the rotor permanent magnet, and the quadrature axis is perpendicular to the direct axis and leads the direct axis by 90°.

[0015] Furthermore, the rotation angle within the preset range is smaller than the ratio of 360° to the number of motor pole pairs.

[0016] In a second aspect, the present invention provides a device for calibrating the electrical angle zero position of a three-phase brushless motor under limited rotation angle constraints, comprising: a parameter setting module for setting field-oriented control parameters of a three-phase brushless motor with angle sensor feedback and a rotation angle limited to a preset range, wherein the quadrature-axis voltage is set to zero and the direct-axis voltage is set to a preset negative value; The acquisition module determines the rotation angle range of the three-phase brushless motor and obtains the maximum and minimum angle values ​​fed back by the angle sensor; The adjustment module rotates the three-phase brushless motor to near the center of the rotation angle range and then starts it. The estimated electrical angle is set to the initial value and the angle sensor feedback value is detected after the motor rotor stabilizes. The judgment module calculates the electrical angle zero position based on the corresponding relationship between the angle sensor feedback value, the electrical angle estimate value, and the number of motor pole pairs if the stabilized angle sensor feedback value is within the rotation angle range. If the angle sensor feedback value after stabilization is at the boundary of the rotation angle range, the electrical angle estimate is adjusted so that the angle sensor feedback value after stabilization of the motor rotor is within the rotation angle range. Then, the electrical angle zero position is calculated based on the correspondence between the adjusted electrical angle estimate, the stabilized angle sensor feedback value, and the number of motor pole pairs. The electrical angle zero position is the angle sensor feedback position corresponding to the center axis of the motor stator A phase winding, and the corresponding relationship is: The electrical angle zero position is equal to the stabilized angle sensor feedback value minus the ratio of the electrical angle estimate to the number of motor pole pairs.

[0017] In a third aspect, the present invention provides an electronic device comprising a memory and a processor, wherein the memory stores a computer program, and the processor is configured to run the computer program to execute the above-mentioned method for zero-position calibration of the electrical angle of a three-phase brushless motor under limited rotation angle constraints.

[0018] In a fourth aspect, the present invention provides a readable storage medium, in which a computer program is stored. The computer program includes a program code for controlling a process to execute a process. The process includes a method for zero-position calibration of the electrical angle of a three-phase brushless motor under the above-mentioned finite angle constraint.

[0019] The main contributions and innovations of the present invention are as follows: 1. Strong applicability: No need for large-range motor rotation, calibration can be achieved under limited rotation angle constraints, suitable for scenes with limited rotation angles such as robot joints and gimbals; 2. Accurate calibration: This eliminates the deviation caused by the motor zero position being stuck outside the range in existing technologies. The zero position is directly calculated through a formula, and the calibration accuracy is equivalent to the angle sensor accuracy (for example, a 0.1°-level encoder can achieve 0.1°-level calibration). 3. Reliable operation: By controlling the voltage parameters ( ) Ensure that the rotor is stable within a controllable range without relying on external forces or high-speed rotation, reducing operational risks; 4. High universality: Suitable for all types of three-phase brushless motors (PMSM, BLDC, etc.) and angle sensors (photoelectric encoders, Hall sensors, etc.), with strong compatibility.

[0020] The details of one or more embodiments of the invention are set forth in the accompanying drawings and the description below so that other features, objects, and advantages of the invention are more readily apparent. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The drawings described herein are used to provide a further understanding of the present invention and constitute a part of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings: Figure 1 is a flow chart of a method for zero-position calibration of a three-phase brushless motor electrical angle under limited rotation angle constraints according to an embodiment of the present invention; Figure 2 1 is a diagram showing the correspondence between the ABC axis, the αβ axis, and the qd axis of a motor according to an embodiment of the present invention; Figure 3 is a schematic diagram showing that the electrical angle zero position is outside the motor rotation range according to an embodiment of the present invention; Figure 4 FIG. 4 is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention.

[0022] In the figure, 1. Motor guide rail; 2. Three-phase brushless motor; 3. Angle sensor. DETAILED DESCRIPTION

[0023] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. In the following description, when referring to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The implementations described in the following exemplary embodiments are not intended to represent all implementations consistent with one or more embodiments of this specification. Rather, they are merely examples of apparatuses and methods consistent with certain aspects of one or more embodiments of this specification, as detailed in the appended claims.

[0024] It should be noted that in other embodiments, the steps of the corresponding method are not necessarily performed in the order shown and described in this specification. In some other embodiments, the method may include more or fewer steps than those described in this specification. In addition, a single step described in this specification may be broken down into multiple steps for description in other embodiments, and multiple steps described in this specification may be combined into a single step for description in other embodiments.

[0025] Traditional FOC control requires calibrating the electrical angle zero position (the position where the rotor D axis is aligned with the stator A phase winding axis). However, in scenarios with limited rotation angles (such as robot joints and gimbals): Methods that rely on rotational speed to generate back electromotive force are not applicable (the rotation angle is limited and high-speed rotation is impossible); The three-phase high and low level pickup method may cause the motor to get stuck at the rotation angle boundary, resulting in large calibration value deviation (the zero position may be outside the rotation angle range).

[0026] Based on this, the present invention solves the problems existing in the prior art by implementing the mapping between the three-phase stationary coordinate system (ABC) and the rotor synchronous rotating coordinate system (qd) through Clark-Park transformation.

[0027] Example 1 The present invention aims to propose a method for calibrating the electrical angle zero position of a three-phase brushless motor under a limited rotation angle constraint. Figure 1 , the method comprises the following steps: Step 1: For a three-phase brushless motor 2 with feedback from an angle sensor 3 and a rotation angle limited to a preset range, set the field-oriented control parameters of the three-phase brushless motor 2, wherein the quadrature-axis voltage is set to zero and the direct-axis voltage is set to a preset negative value; In this embodiment, the core of FOC (field oriented control) of the three-phase brushless motor 2 is to achieve precise control of the motor through coordinate transformation, specifically by completing the mapping of different coordinate systems through Clark-Park transformation and inverse transformation, such as Figure 2 As shown: 1) Clark transform and inverse transform: Responsible for converting the stator's three-phase stationary coordinate system (ABC axes, corresponding to the motor's three-phase windings) to and from the two-phase stationary coordinate system (αβ axes). The inverse Clark transform is implicit in SVPWM (space vector pulse width modulation) control, achieving the conversion from the αβ axes to the ABC axes.

[0028] 2) Park Transform and Inverse Transform: These transforms between the two-phase stationary coordinate system (αβ axes) and the synchronously rotating coordinate system of the rotor magnetic field (qd axis). In the qd coordinate system, the d-axis (direct axis) always points toward the north pole of the rotor permanent magnet, controlling the flux strength. The q-axis (quadrature axis) is perpendicular to the d-axis and leads by 90°, providing rotor torque.

[0029] The angle between the α-axis of the stationary coordinate system and the d-axis of the rotating coordinate system is the electrical angle, a key parameter in FOC control. Only with an accurate electrical angle can coordinate transformation achieve precise matching of the stator and rotor magnetic fields, ensuring effective control. Therefore, the electrical angle zero position (i.e., the position where the d-axis and α-axis coincide) must be calibrated.

[0030] The core of the three-phase motor electrical angle zero calibration is to align the rotor's d-axis (the direct axis that always points to the N pole of the rotor's permanent magnet) with the axis of a stator phase winding. The axis of the A-phase winding is usually selected as the alignment reference. At this time, the position value fed back by the angle sensor 3 is the electrical angle zero calibration value (denoted as Since the motor has a pole pair number p (the number of magnetic pole pairs of the rotor permanent magnets), the d-axis will align with the axis of the A-phase winding p times for each rotation of the rotor (360° mechanical angle) - these zero positions are evenly spaced in mechanical angle, with an interval of 360° / p.

[0031] For example, when p=6, a zero position will appear every 60° mechanical angle. However, in a limited angle scenario (e.g., the motor can only rotate within a range less than 360° / p due to structural constraints), all zero positions may be outside the angle range, such as Figure 3 As shown in the figure, A and B represent the two boundaries of the motor travel, Z1 and Z2 represent the motor electrical angle zero position (outside the travel). In this case, the traditional calibration method will not be able to obtain the accurate zero position because the motor is stuck at the angle boundary. Therefore, the core of the present invention is to solve the problem of how to accurately measure the zero position under such limited angle constraints. .

[0032] Therefore, in this step, the first step is to determine the reasonable In FOC control, the dq axis output voltage is Set to 0, voltage Set to ,in is greater than zero, and Cannot be too small or too large, too small Unable to overcome the torque required for motor rotation, too large It is easy to damage the motor, here is reasonable The setting value can be determined as follows: first Set to zero, electrical angle estimation Set to zero, rotate the motor shaft until the motor moves to the center of the limit stroke of motor guide rail 1 (the gear on the motor shaft meshes with the teeth on motor guide rail 1), and then slowly increase If there is no external force, the motor will rotate towards the electrical angle zero position. At this time, use your hand or a torque meter to test the motor's rotational torque. When the torque generated by the motor can easily rotate the motor shaft, but in order not to damage the motor, It cannot be too high. According to the voltage limit circle formula of FOC control (geometric boundary theory of SVPWM inverter output voltage):

[0033] in, is the rated voltage of the motor, when = 0, | Less than or equal to ,Here the present invention retains a certain engineering margin, | Less than 57% of the rated voltage, that is The value is less than 57% of the rated voltage For example, a motor with a rated voltage of 24V, The value should not exceed 13.68V if When the motor still does not generate torque capable of driving the motor shaft to rotate when the rated voltage is greater than 57%, it is necessary to check whether there is a problem with the motor's drive circuit or whether the friction coefficient of the motor shaft is too large. Value, taking the rated voltage 24V motor as an example, first we can calculate , and then increase from 0 value, and manually rotate the motor shaft randomly at the same time, a certain torque will be generated towards the stable point Direction rotation, just like a compass will eventually point to the south after being turned by an external force. When the motor shaft has this rotation trend, record the current ,For example , then we can use the empirical formula: +

[0034] Sure Value, such as in the example above = 8.34V, which is a reasonable value measured with this setup Then you can proceed to the next step.

[0035] Step 2: Determine the rotation angle range of the three-phase brushless motor 2 and obtain the maximum angle value and the minimum angle value fed back by the angle sensor 3; In this embodiment, the motor rotation angle range is determined and the maximum and minimum values ​​of the motor angle sensor 3 are read. Since the motor rotation angle is limited in the present invention, the motor angle sensor 3 also has upper and lower limits. The maximum value of the angle sensor 3 is A and the minimum value is B, that is, Figure 3 The upper limit of the travel of motor A, the lower limit of the travel of motor B, Z1 and Z2 are the angle zero positions of the two motor points, which are located outside the travel of motor guide rail 1.

[0036] Step 3: Rotate the three-phase brushless motor 2 to near the center of the rotation angle range and start it, set the estimated electrical angle to the initial value, and detect the feedback value of the angle sensor 3 after the motor rotor stabilizes; In this embodiment, when performing electrical angle zero calibration, the motor is manually rotated (or the motor can be automatically driven by other equipment) to the center of the rotation range, that is, the median value (A+B) / 2 of the angle transmission reading range, when the motor is powered off. Then the motor is started and the zero position calibration is still performed. Set to 0, voltage Set to , set the estimated electrical angle of the motor Set it to zero and observe the stable position after the motor rotates. There are two situations: The first one is that the stable position of the motor is within the range of motor rotation, that is, the area (A, B). so = .

[0037] The second type is that the motor is in a stable position close to the boundary of the rotation range, that is, the maximum value A or the minimum value B of the angle sensor 3. At this time, the electrical angle estimate is adjusted. , increase or decrease value, so that the stable position of the motor leaves the boundary of the rotation range and moves towards the center of the stroke, for example, through Adjust the motor to leave the boundary position and stabilize at point C within the travel range. = , angle sensor 3 reading ,So = - .

[0038] Because the electrical angle zero calibration value According to the feedback value of angle sensor 3 Calculated, the accuracy of the angle sensor 3 is directly equal to the calibration accuracy of the electrical angle zero position.

[0039] In this embodiment, the three-phase motor FOC control is used to adjust the output of the quadrature axis q and the direct axis d and the electrical angle estimation value. , and the feedback value of motor angle sensor 3 The electrical angle zero position is measured. In the three-phase motor FOC control, the electromagnetic torque equation is:

[0040] in, is the electromagnetic torque of the motor; is the q-axis current; is the d-axis current; is the pole pair number; is the permanent magnet flux; is the q-axis inductance; is the d-axis inductance.

[0041] Here, the output voltage of the q axis is Set to 0, the output voltage of the d-axis Set to ,in Greater than zero, we can get , = , and then the electromagnetic torque can be obtained =0, that is, the motor stator has no torque output at this time, but because there is direct axis current = The existence of the motor, according to the electromagnetic law, the stator will still generate a magnetic field. Greater than zero, that is - When it is less than zero, It is a "magnetic assist" current, that is, the direction of the magnetic field generated by the motor stator will attract the direction of the rotor's magnetic field to a position that is completely aligned with the d-axis (the stator and rotor magnetic fields are parallel, and the N pole of the rotor is aligned with the N pole of the stator).

[0042] At this time, under the premise of no external force, the motor rotor will remain stationary here. To use an image analogy, the motor rotor is a permanent magnet, like a compass. If the present invention does not apply external force to the compass, the S pole of the compass will naturally point to the N pole of the geomagnetic field (the geographical South Pole). The present invention previously set is less than 0, an external magnetic field similar to the Earth's magnetic field is generated, and =0, that is, the torque perpendicular to the direction of the external magnetic field is zero (no external force is applied), so the S pole of the "compass" will naturally point to the N pole of the external magnetic field. In this analogy of the present invention, the direction of the "earth magnetic field" is generated by the d-axis. At this time, the feedback value (angle sampling value) of the angle sensor 3 in this direction is , but this external magnetic field is quite special. Although it is described as being formed under the action of the qd axis, it is actually the resultant magnetic field formed by the stator ABC windings being energized at 120° electrical angles to each other (see Figure 2 ), but this complex magnetic field can be transformed into the form of qd axis through Clark-Park transformation, Clark transforms it into ABC axis αβ axis projection, the formula is as follows:

[0043] The park change is the projection of the αβ axis to the qd axis, and the formula is as follows:

[0044] Combining the above formula Figure 2 The present invention can obtain the angle between the d-axis of the rotating coordinate system and the α-axis (A-axis) of the stationary coordinate system, which is the estimated electrical angle. , which is the stable position of the motor rotor, especially when = 0, the d axis directly coincides with the α axis (A axis). = , and when ≠0, the stable position of the motor rotor is , this position and the motor zero position The difference is / ,here It is the number of pole pairs of the motor, because there is a magnification relationship between the electrical angle value of the motor and the feedback value of the motor angle sensor 3 For example, when the motor rotates from point A to point B, the rotation angle fed back by angle sensor 3 is , then the rotation value of the motor's electrical angle is , so the present invention can derive the formula: = ( - ) By shifting the above formula, we can get: = -

[0045] in, is the zero position of the electrical angle; It is the estimated value of the electrical angle in FOC control; It is the feedback value of angle sensor 3 after the motor rotor stabilizes; is the number of pole pairs of the motor. In this formula, the number of pole pairs of the motor is a fixed parameter of the motor. The position of the electrical angle zero is the feedback position of the angle sensor 3 corresponding to the center axis of the motor stator A phase winding. This position is determined after the motor and angle sensor 3 are installed. and are all fixed values, so the present invention has established and The corresponding relationship, that is, when Set to 0, Set to When the electrical angle is estimated Corresponding to the stable position of the motor .

[0046] Step 4: If the feedback value of the angle sensor 3 after stabilization is within the rotation angle range, the electrical angle zero position is calculated based on the corresponding relationship between the feedback value of the angle sensor 3, the estimated electrical angle value, and the number of motor pole pairs; If the feedback value of the angle sensor 3 after stabilization is at the boundary of the rotation angle range, the electrical angle estimation value is adjusted so that the feedback value of the angle sensor 3 after stabilization of the motor rotor is within the rotation angle range, and then the electrical angle zero position is calculated based on the correspondence between the adjusted electrical angle estimation value, the feedback value of the angle sensor 3 after stabilization and the number of motor pole pairs; The electrical angle zero position is the feedback position of the angle sensor 3 corresponding to the center axis of the motor stator A phase winding, and the corresponding relationship is: The electrical angle zero position is equal to the stabilized feedback value of the angle sensor 3 minus the ratio of the electrical angle estimate to the number of motor pole pairs.

[0047] In this embodiment, for example, the accuracy of the 3600P / R photoelectric encoder is about 0.1°, so the accuracy of the electrical angle zero calibration value measured by the present invention is also about 0.1°. In particular, if a rotary potentiometer type angle sensor 3 is used for feedback, because the accuracy and linearity of the angle feedback value of many rotary potentiometers are better at the center of the rotation range than at both ends, it can be adjusted. The value of makes the shaft stable at the center of the potentiometer's rotation range. At this time, the measured electrical angle zero position calibration value has the highest accuracy.

[0048] In this way, the present invention calibrates the zero position of the electrical angle , in the subsequent FOC control, the current electrical angle value of the motor can be calculated by the following formula: = ( -

[0049] in, is the number of pole pairs of the motor, is the current reading value of motor angle sensor 3, It is the motor electrical angle zero position calibration value measured through the previous three steps.

[0050] In summary, under limited angle constraints, the electrical angle zero calibration value measured by the present invention is more accurate and reliable than the electrical angle zero calibration value measured by three-phase attraction. The following example uses a motor with a 40-degree rotation stroke constraint for comparison. The stroke range is 10° to 50°, and the motor =6, angle sensor 3 uses a photoelectric encoder with 0.1° accuracy, assuming the motor's true electrical angle is zero =(5+60×n)°, which is 6 points in total: 5°, 65°, 125°, 185°, 245°, and 305°. Since the electrical angle zero position appears every 60°, the electrical angle zero position calibration value can be obtained by measuring any of the above points.

[0051] In order to demonstrate the technical effect of the present invention, the present invention is also compared with the existing common three-phase high and low level pickup scheme, as shown in Table 1 below: Table 1

[0052] It can be seen that the present invention stabilizes the rotor within the stroke range by actively adjusting the estimated electrical angle, and calculates the zero position in combination with the formula, thereby solving the calibration value deviation problem caused by boundary constraints in traditional high and low level attraction schemes. It is more accurate and reliable in limited angle scenarios.

[0053] Example 2 Based on the same concept, the present invention also proposes a device for calibrating the electrical angle zero position of a three-phase brushless motor under limited rotation angle constraints, comprising: a parameter setting module for setting the field-oriented control parameters of the three-phase brushless motor 2 with feedback from the angle sensor 3 and a rotation angle limited to a preset range, wherein the quadrature-axis voltage is set to zero and the direct-axis voltage is set to a preset negative value; The acquisition module determines the rotation angle range of the three-phase brushless motor 2 and obtains the maximum and minimum angle values ​​fed back by the angle sensor; The adjustment module rotates the three-phase brushless motor 2 to near the center of the rotation angle range and then starts it, sets the estimated electrical angle to the initial value, and detects the angle sensor feedback value after the motor rotor stabilizes; The judgment module calculates the electrical angle zero position based on the corresponding relationship between the angle sensor feedback value, the electrical angle estimate value, and the number of motor pole pairs if the stabilized angle sensor feedback value is within the rotation angle range. If the angle sensor feedback value after stabilization is at the boundary of the rotation angle range, the electrical angle estimate is adjusted so that the angle sensor feedback value after stabilization of the motor rotor is within the rotation angle range. Then, the electrical angle zero position is calculated based on the correspondence between the adjusted electrical angle estimate, the stabilized angle sensor feedback value, and the number of motor pole pairs. The electrical angle zero position is the angle sensor feedback position corresponding to the center axis of the motor stator A phase winding, and the corresponding relationship is: The electrical angle zero position is equal to the stabilized angle sensor feedback value minus the ratio of the electrical angle estimate to the number of motor pole pairs.

[0054] Example 3 This embodiment also provides an electronic device, referring to Figure 4 , includes a memory 404 and a processor 402, wherein the memory 404 stores a computer program, and the processor 402 is configured to run the computer program to perform the steps in any of the above method embodiments.

[0055] Specifically, the processor 402 may include a central processing unit (CPU), or an application specific integrated circuit (ASIC), or may be configured to implement one or more integrated circuits for implementing the embodiments of the present invention.

[0056] Memory 404 may include a large-capacity memory 404 for data or instructions. By way of example, and not limitation, memory 404 may include a hard disk drive (HDD), a floppy disk drive, a solid-state drive (SSD), flash memory, an optical disk, a magneto-optical disk, a magnetic tape, or a Universal Serial Bus (USB) drive, or a combination of two or more of these. Where appropriate, memory 404 may include removable or non-removable (or fixed) media. Where appropriate, memory 404 may be internal or external to the data processing device. In certain embodiments, memory 404 is non-volatile memory. In certain embodiments, memory 404 includes read-only memory (ROM) and random access memory (RAM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable ROM (PROM), an erasable PROM (EPROM), an electrically erasable PROM (EEPROM), an electrically alterable ROM (EAROM) or a flash memory (FLASH), or a combination of two or more of these. In appropriate circumstances, the RAM may be a static random access memory (SRAM) or a dynamic random access memory (DRAM), wherein the DRAM may be a fast page mode dynamic random access memory 404 (FPMDRAM), an extended data output dynamic random access memory (EDODRAM), a synchronous dynamic random access memory (SDRAM), etc.

[0057] The memory 404 may be used to store or cache various data files required for processing and / or communication, as well as possible computer program instructions executed by the processor 402 .

[0058] The processor 402 reads and executes computer program instructions stored in the memory 404 to implement any one of the methods for zero-position calibration of the electrical angle of a three-phase brushless motor under limited rotation angle constraints in the above embodiments.

[0059] Optionally, the electronic device may further include a transmission device 406 and an input / output device 408 , wherein the transmission device 406 is connected to the processor 402 , and the input / output device 408 is connected to the processor 402 .

[0060] Transmission device 406 can be used to receive or transmit data via a network. Specific examples of such networks may include wired or wireless networks provided by the electronic device's communications provider. In one embodiment, the transmission device includes a network interface controller (NIC), which can be connected to other network devices via a base station to enable communication with the Internet. In another embodiment, transmission device 406 can be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0061] The input / output device 408 is used to input or output information.

[0062] Example 4 This embodiment also provides a readable storage medium, which stores a computer program. The computer program includes a program code for controlling a process to execute a process. The process includes a method for zero-position calibration of the electrical angle of a three-phase brushless motor under a limited angle constraint according to embodiment one.

[0063] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementation modes, and this embodiment will not be repeated here.

[0064] In general, various embodiments may be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects of the invention may be implemented in hardware, while other aspects may be implemented in firmware or software executed by a controller, microprocessor, or other computing device, but the invention is not limited thereto. Although various aspects of the invention may be shown and described as block diagrams, flow charts, or using some other graphical representation, it should be understood that, as non-limiting examples, the blocks, devices, systems, techniques, or methods described herein may be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or a controller or other computing device, or some combination thereof.

[0065] The embodiments of the present invention may be implemented by computer software that is executable by a data processor of a mobile device, such as in a processor entity, or by hardware, or by a combination of software and hardware. Computer software or programs (also referred to as program products) including software routines, applets and / or macros may be stored in any device-readable data storage medium, and they include program instructions for performing specific tasks. A computer program product may include one or more computer executable components that are configured to perform an embodiment when the program is run. One or more computer executable components may be at least one software code or a portion thereof. In addition, it should be noted at this point that, for example, Figure 1 Any block of the logic flow in the program may represent program steps, or interconnected logic circuits, blocks and functions, or a combination of program steps and logic circuits, blocks and functions. The software may be stored on physical media such as memory chips or memory blocks implemented within the processor, magnetic media such as hard disks or floppy disks, and optical media such as, for example, DVDs and their data variants, CDs, etc. Physical media are non-transitory media.

[0066] Those skilled in the art should understand that the technical features of the above embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0067] The above embodiments merely illustrate several embodiments of the present invention, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that a person skilled in the art would be able to make various modifications and improvements without departing from the spirit of the present invention, all of which fall within the scope of the present invention. Therefore, the scope of the present invention shall be determined by the appended claims.

Claims

1. A method for zeroing the electrical angle of a three-phase brushless motor under limited rotation angle constraints, characterized in that: The following steps are involved: Step 1: For a three-phase brushless motor with angle sensor feedback and a rotation angle limited to a preset range, setting the field-oriented control parameters of the three-phase brushless motor, wherein the quadrature-axis voltage is set to zero and the direct-axis voltage is set to a preset negative value; Step 2: Determine the rotation angle range of the three-phase brushless motor and obtain the maximum angle value and the minimum angle value fed back by the angle sensor; Step 3: The three-phase brushless motor is rotated to near the center of the rotation angle range and then started, the estimated electrical angle is set as an initial value, and the angle sensor feedback value after the motor rotor is stabilized is detected; Step 4: If the stabilized angle sensor feedback value is within the rotation angle range, the electrical angle zero position is calculated according to the corresponding relationship between the angle sensor feedback value, the electrical angle estimated value, and the number of motor pole pairs; If the stabilized angle sensor feedback value is at the boundary of the rotation angle range, the electrical angle estimate value is adjusted so that the stabilized angle sensor feedback value of the motor rotor is within the rotation angle range, and then the electrical angle zero position is calculated based on the correspondence between the adjusted electrical angle estimate value, the stabilized angle sensor feedback value, and the number of motor pole pairs; The electrical angle zero position is the angle sensor feedback position corresponding to the center axis of the motor stator A phase winding, and the corresponding relationship is: The electrical angle zero position is equal to the stabilized angle sensor feedback value minus the ratio of the electrical angle estimate to the number of motor pole pairs.

2. The method for calibrating the electrical angle zero position of a three-phase brushless motor under limited rotation angle constraints as claimed in claim 1, characterized in that: In step 1, the absolute value of the preset negative value of the direct-axis voltage is a preset voltage value, and the preset voltage value does not exceed 55-60% of the rated voltage of the motor.

3. The method for zero-position calibration of the electrical angle of a three-phase brushless motor under limited rotation angle constraint according to claim 2, characterized in that: Determining the preset voltage value includes: gradually increasing the voltage value from an initial value until the three-phase brushless motor generates a stable torque that can drive the rotor to rotate, and the voltage value does not exceed 57% of the rated voltage of the motor, and taking this voltage value as the preset voltage value.

4. The method for zero-position calibration of the electrical angle of a three-phase brushless motor under limited rotation angle constraint according to claim 1, characterized in that: In step 3, the initial value of the electrical angle estimation is zero.

5. The method for calibrating the electrical angle zero position of a three-phase brushless motor under limited rotation angle constraint according to claim 1, characterized in that: In step 4, the method for adjusting the estimated electrical angle is as follows: The electrical angle estimation value is increased or decreased so that the angle sensor feedback value after the motor rotor is stabilized moves toward the center of the rotation angle range.

6. The method for calibrating the electrical angle zero position of a three-phase brushless motor under limited rotation angle constraints as claimed in claim 1, characterized in that: In step 1, the field-oriented control realizes the mapping of the three-phase stationary coordinate system and the rotor synchronous rotating coordinate system through Clark-Park transformation and inverse transformation, the direct axis is the magnetic field direction of the rotor permanent magnet, and the quadrature axis is perpendicular to the direct axis and leads the direct axis by 90°.

7. A method for zero-position calibration of the electrical angle of a three-phase brushless motor under limited rotation angle constraints according to any one of claims 1 to 6, characterized in that: The rotation angle within the preset range is smaller than the ratio of 360° to the number of motor pole pairs.

8. A device for zero-position calibration of the electrical angle of a three-phase brushless motor under limited rotation angle constraints, characterized in that: include: a parameter setting module for setting field-oriented control parameters of a three-phase brushless motor with angle sensor feedback and a rotation angle limited to a preset range, wherein the quadrature-axis voltage is set to zero and the direct-axis voltage is set to a preset negative value; The acquisition module determines the rotation angle range of the three-phase brushless motor and obtains the maximum and minimum angle values ​​fed back by the angle sensor; The adjustment module rotates the three-phase brushless motor to near the center of the rotation angle range and then starts it. The estimated electrical angle is set to the initial value and the angle sensor feedback value is detected after the motor rotor stabilizes. The judgment module calculates the electrical angle zero position based on the corresponding relationship between the angle sensor feedback value, the electrical angle estimate value, and the number of motor pole pairs if the stabilized angle sensor feedback value is within the rotation angle range. If the angle sensor feedback value after stabilization is at the boundary of the rotation angle range, the electrical angle estimate is adjusted so that the angle sensor feedback value after stabilization of the motor rotor is within the rotation angle range. Then, the electrical angle zero position is calculated based on the correspondence between the adjusted electrical angle estimate, the stabilized angle sensor feedback value, and the number of motor pole pairs. The electrical angle zero position is the angle sensor feedback position corresponding to the center axis of the motor stator A phase winding, and the corresponding relationship is: The electrical angle zero position is equal to the stabilized angle sensor feedback value minus the ratio of the electrical angle estimate to the number of motor pole pairs.

9. An electronic device comprising a memory and a processor, characterized in that: A computer program is stored in the memory, and the processor is configured to run the computer program to execute the method for zero-position calibration of the electrical angle of a three-phase brushless motor under limited rotation angle constraints as claimed in any one of claims 1 to 7.

10. A readable storage medium, characterized in that: The readable storage medium stores a computer program, which includes a program code for controlling a process to execute a process, and the process includes a method for zero-position calibration of the electrical angle of a three-phase brushless motor under limited rotation angle constraints according to any one of claims 1 to 7.

Images