Method and device for calibrating electrical angle zero position of three-phase brushless motor under limited rotation angle constraint and readable storage medium thereof

Abstract

This invention proposes a method, apparatus, and readable storage medium for zero-position calibration of the electrical angle of a three-phase brushless motor under limited rotation angle constraints, belonging to the field of three-phase brushless motor control technology. Addressing the problem of inaccurate calibration in existing methods under limited rotation angle scenarios due to reliance on high-speed motor rotation or zero-position exceeding the range, this invention stabilizes the rotor at the position corresponding to the predicted electrical angle by setting the quadrature-axis voltage to 0 and the direct-axis voltage to a preset negative value in the FOC control. After determining the rotation angle range, the predicted electrical angle is adjusted to ensure the rotor remains stable within the range. Then, based on the stabilized angle sensor feedback value, the predicted electrical angle, and the number of pole pairs, the zero-position of the electrical angle is calculated through a specific relationship. This method does not require large-range motor rotation, has high calibration accuracy, is suitable for scenarios with limited rotation angles such as robot joints and gimbals, and exhibits strong reliability.

Description

Technical Field

[0001] This invention relates to the field of three-phase brushless motor control technology, and in particular to a method, apparatus and readable storage medium for zero-position calibration of electrical angle of a three-phase brushless motor under finite rotation angle constraints. Background Technology

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

[0003] For example, CN113063345A discloses a method for calibrating the zero-position angle of a motor. Its core principle is to control the three-phase current to make the magnetic field vector coincide with the axis of phase A, obtain the position angle, and then control the rotor to rotate by a preset angle (360° / number of pole pairs). This process is repeated multiple times, and the zero position is calculated by averaging the results. This method relies on the rotor rotating at a specific angle (360° / number of pole pairs). 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 method for identifying the electrical angle of a brushless motor. This method involves applying a micro-current to rotate the rotor to a relative zero position and then calculating the absolute zero position based on the d / q-axis current components. However, this method requires the rotor to rotate to a relative zero position. If the zero position is outside the rotation angle range, the rotor may become stuck at the boundary, making it impossible to accurately obtain the relative zero position. Therefore, it is not suitable for scenarios with finite rotation angle constraints.

[0005] It is evident that existing electrical angle zero-point calibration methods mainly suffer from the following two types of problems:

[0006] Firstly, the method of using the peak value of the back electromotive force to calibrate the zero position by increasing the motor speed relies on the motor rotating over a wide range, which is not applicable to scenarios where the motor can only rotate within a limited angle due to structural constraints.

[0007] Secondly, calibration is performed by connecting the motor to high and low voltage levels on all three phases to make the motor engage at a certain angle. However, when the electrical angle zero point is outside the motor's rotation angle range, the motor may be stationary close to the rotation angle boundary, resulting in a large deviation between the calibrated zero point and the actual zero point, and the accuracy cannot be guaranteed.

[0008] Therefore, under the constraint of limited rotation angle, there is an urgent need for a reliable and accurate method, device and readable storage medium for zero-position calibration of electrical angle of three-phase brushless motor. Summary of the Invention

[0009] This invention provides a method, apparatus, and readable storage medium for calibrating the electrical angle zero position of a three-phase brushless motor under finite angle constraints. It addresses the problems of existing technologies being unsuitable under finite angle constraints due to either reliance on high-speed motor rotation (such as the back electromotive force method) or the possibility that the electrical angle zero position may be outside the angle range, causing the motor to get stuck at the boundary and resulting in inaccurate calibration results.

[0010] The core technology of this invention mainly involves setting the quadrature axis voltage in FOC control. Direct-axis voltage This stabilizes the rotor at the predicted electrical angle. Adjust the corresponding position. Ensure the rotor remains stable within the rotation angle range, and then based on the formula (p is the extreme logarithm, The electrical angle zero position is calculated based on the sensor feedback value.

[0011] In a first aspect, the present invention provides a method for zero-position calibration of the electrical angle of a three-phase brushless motor under finite rotation angle constraints, the method comprising the following steps:

[0012] Step 1: For a three-phase brushless motor with angle sensor feedback and rotation angle limited to a preset range, set the field orientation 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.

[0013] 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;

[0014] Step 3: After rotating the three-phase brushless motor to near the center of the rotation angle range, start it, set the electrical angle prediction value to the initial value, and detect the angle sensor feedback value after the motor rotor stabilizes;

[0015] Step 4: If the stabilized angle sensor feedback value is within the rotation angle range, calculate the zero position of the electrical angle based on the correspondence between the angle sensor feedback value, the electrical angle prediction value, and the number of motor pole pairs.

[0016] If the feedback value of the angle sensor after stabilization is at the boundary of the rotation angle range, adjust the electrical angle prediction value so that the feedback value of the angle sensor after the motor rotor stabilizes is within the rotation angle range. Then, calculate the electrical angle zero position based on the correspondence between the adjusted electrical angle prediction value, the stable angle sensor feedback value, and the number of motor pole pairs.

[0017] Among them, the electrical angle zero position is the angle sensor feedback position corresponding to the central axis of the A-phase winding of the motor stator, and the corresponding relationship is as follows:

[0018] The zero electrical angle is equal to the ratio of the stabilized angle sensor feedback value to the estimated electrical angle value and the number of pole pairs of the motor.

[0019] Furthermore, in step 1, the absolute value of the preset negative value of the direct shaft voltage is the preset voltage value, and the preset voltage value does not exceed 55~60% of the rated voltage of the motor.

[0020] Furthermore, the determination of the preset voltage value includes: gradually increasing the voltage value from the 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 motor's rated voltage, and taking this voltage value as the preset voltage value.

[0021] Furthermore, in step 3, the initial value of the electrical angle estimate is zero.

[0022] Furthermore, in step 4, the method for adjusting the estimated electrical angle is as follows:

[0023] Increase or decrease the electrical angle prediction value to move the angle sensor feedback value after the motor rotor stabilizes towards the center of the rotation angle range.

[0024] Furthermore, in step 1, the magnetic field orientation control realizes the mapping between 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 direction of the magnetic field of the rotor permanent magnet, and the quadrature axis is perpendicular to the direct axis and leads the direct axis by 90°.

[0025] Furthermore, the rotation angle within the preset range is less than the ratio of 360° to the number of motor pole pairs.

[0026] Secondly, the present invention provides a device for zero-position calibration of the electrical angle of a three-phase brushless motor under finite rotation angle constraints, comprising:

[0027] The parameter setting module sets the magnetic field orientation control parameters of a three-phase brushless motor that has angle sensor feedback and whose rotation angle is limited to a preset range. Among them, the quadrature axis voltage is set to zero and the direct axis voltage is set to a preset negative value.

[0028] The data 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.

[0029] The adjustment module rotates the three-phase brushless motor to near the center of the rotation angle range and then starts it. The electrical angle prediction value is set as the initial value, and the angle sensor feedback value is detected after the motor rotor stabilizes.

[0030] If the feedback value from the angle sensor after stabilization is within the rotation angle range, the judgment module calculates the zero position of the electrical angle based on the correspondence between the angle sensor feedback value, the electrical angle prediction value, and the number of pole pairs of the motor.

[0031] If the feedback value of the angle sensor after stabilization is at the boundary of the rotation angle range, adjust the electrical angle prediction value so that the feedback value of the angle sensor after the motor rotor stabilizes is within the rotation angle range. Then, calculate the electrical angle zero position based on the correspondence between the adjusted electrical angle prediction value, the stable angle sensor feedback value, and the number of motor pole pairs.

[0032] Among them, the electrical angle zero position is the angle sensor feedback position corresponding to the central axis of the A-phase winding of the motor stator, and the corresponding relationship is as follows:

[0033] The zero electrical angle is equal to the ratio of the stabilized angle sensor feedback value to the estimated electrical angle value and the number of pole pairs of the motor.

[0034] Thirdly, the present invention provides an electronic device including a memory and a processor, wherein the memory stores a computer program and the processor is configured to run the computer program to perform the above-described method for zero-position calibration of the electrical angle of a three-phase brushless motor under finite angle constraints.

[0035] Fourthly, the present invention provides a readable storage medium storing a computer program, the computer program including program code for controlling a process to execute the process, the process including a method for zero-position calibration of the electrical angle of a three-phase brushless motor under the aforementioned finite angle constraint.

[0036] The main contributions and innovations of this invention are as follows:

[0037] 1. High applicability: No need for a large range of motor rotation, calibration can be achieved under limited rotation angle constraints, suitable for robot joints, gimbals and other scenarios with limited rotation angles;

[0038] 2. Accurate calibration: It avoids the deviation caused by the motor being stuck at the boundary outside the range in the existing technology. The zero position is directly calculated by formula, and the calibration accuracy is equivalent to that of the angle sensor (such as 0.1° level encoder can achieve 0.1° level calibration).

[0039] 3. Reliable operation: By controlling voltage parameters ( This ensures that the rotor remains stable within a controllable range, without relying on external forces or high-speed rotation, thus reducing operational risks.

[0040] 4. High versatility: Applicable to various three-phase brushless motors (PMSM, BLDC, etc.) and angle sensors (photoelectric encoders, Hall sensors, etc.), with strong compatibility.

[0041] Details of one or more embodiments of the present invention are set forth in the following drawings and description, so that other features, objects and advantages of the invention will be more readily understood. Attached Figure Description

[0042] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings:

[0043] Figure 1 This is a flowchart of a method for zero-position calibration of the electrical angle of a three-phase brushless motor under finite rotation angle constraints according to an embodiment of the present invention;

[0044] Figure 2 This is a diagram showing the correspondence between the ABC axis, αβ axis, and qd axis of the motor according to an embodiment of the present invention;

[0045] Figure 3 This is a schematic diagram showing the electrical angle zero point outside the motor rotation range according to an embodiment of the present invention;

[0046] Figure 4 This is a schematic diagram of the hardware structure of an electronic device according to an embodiment of the present invention.

[0047] In the diagram, 1 is the motor guide rail; 2 is the three-phase brushless motor; and 3 is the angle sensor. Detailed Implementation

[0048] Exemplary embodiments will now be described in detail, examples of which are illustrated in the accompanying drawings. When the following description relates to the drawings, unless otherwise indicated, the same numerals in different drawings denote the same or similar elements. The embodiments described in the following exemplary embodiments do not represent all embodiments consistent with one or more embodiments of this specification. Rather, they are merely examples of apparatuses and methods consistent with some aspects of one or more embodiments of this specification as detailed in the appended claims.

[0049] It should be noted that the steps of the corresponding methods are not necessarily performed in the order shown and described in this specification in other embodiments. In some other embodiments, the methods may include more or fewer steps than described in this specification. Furthermore, a single step described in this specification may be broken down into multiple steps in other embodiments; and multiple steps described in this specification may be combined into a single step in other embodiments.

[0050] Traditional FOC control requires first calibrating the electrical angle zero position (the position where the rotor d-axis is aligned with the stator A-phase winding axis), but in scenarios with limited rotation angles (such as robot joints and gimbals):

[0051] The method of generating back electromotive force by relying on rotational speed is not applicable (due to limited rotation angle, high-speed rotation is not possible).

[0052] The three-phase high and low level engagement method may cause the motor to get stuck at the corner boundary, resulting in a large deviation in the calibration value (the zero position may be outside the corner range).

[0053] Based on this, the present invention addresses the problems existing in the prior art by mapping the three-phase stationary coordinate system (ABC) to the rotor synchronous rotating coordinate system (qd) through Clark-Park transformation.

[0054] Example 1

[0055] This invention aims to propose a method for zero-position calibration of the electrical angle of a three-phase brushless motor under finite angle constraints. Specifically, refer to... Figure 1 The method includes the following steps:

[0056] Step 1: For the three-phase brushless motor 2 with feedback from angle sensor 3 and rotation angle limited to a preset range, set the magnetic field orientation 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.

[0057] In this embodiment, the core of the FOC (Field Oriented Control) of the three-phase brushless motor 2 lies in achieving precise control of the motor through coordinate transformation. Specifically, it completes the mapping between different coordinate systems through Clark-Park transformation and inverse transformation, such as... Figure 2 As shown:

[0058] 1) Clark transformation and inverse transformation: responsible for converting the stator's three-phase stationary coordinate system (ABC axis, corresponding to the motor's three-phase windings) to the two-phase stationary coordinate system (αβ axis). The Clark inverse transformation is implicit in SVPWM (space vector pulse width modulation) control, realizing the conversion from the αβ axis to the ABC axis.

[0059] 2) Park transformation and inverse transformation: This is responsible for converting between the two-phase stationary coordinate system (αβ axis) and the synchronous rotating coordinate system of the rotor magnetic field (qd axis). In the qd coordinate system, the d-axis (direct axis) always points to the N pole of the rotor permanent magnet, controlling the magnetic flux density; the q-axis (quadrature axis) is perpendicular to the d-axis and leads it by 90°, used to provide rotor torque.

[0060] The angle between the α-axis of the stationary coordinate system and the d-axis of the rotating coordinate system is the electrical angle, which is a key parameter for FOC control. Only when the electrical angle is accurate can the stator magnetic field and the rotor magnetic field be precisely matched through coordinate transformation, ensuring the control effect. Therefore, it is necessary to calibrate the electrical angle zero position (i.e., the position when the d-axis coincides with the α-axis).

[0061] The core of three-phase motor electrical angle zero-position 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 certain phase winding of the stator, typically choosing the axis of phase A winding as the alignment reference. At this point, the position value fed back by angle sensor 3 is the electrical angle zero-position calibration value (denoted as...). Because the motor has a pole pair number p (the number of magnetic pole pairs of the rotor permanent magnet), the d-axis will align with the axis of the A-phase winding p times for every one revolution of the rotor (mechanical angle 360°). These zero positions are equally spaced in mechanical angle, with an interval of 360° / p.

[0062] For example, when p=6, a zero point appears every 60° mechanical angle. However, in scenarios with limited rotation angles (such as when a motor, due to structural constraints, can only rotate within a range less than 360° / p), all zero points may be outside this range. Figure 3 As shown, A and B represent two boundaries on the motor's travel, and Z1 and Z2 represent the motor's electrical angle zero position (outside the travel). In this case, traditional calibration methods cannot obtain an accurate zero position because the motor is stuck at the angle boundary. Therefore, the core of this invention is to solve the problem of how to accurately measure the zero position under such limited angle constraints. .

[0063] Therefore, in this process, the first step is to determine a reasonable... In FOC control, the value is the output voltage of the dq axis. Set to 0, voltage Set to ,in Greater than zero, and It cannot be too small or too large; too small Unable to overcome the torque required for the motor to rotate, too large The motor is easily damaged, so this is a reasonable solution. The set value can be determined in the following ways:

[0064] first Set to zero, estimated electrical angle Set the value to zero, rotate the motor shaft until the motor reaches near the center of the limit stroke of motor guide rail 1 (where the gear on the motor shaft meshes with the teeth on motor guide rail 1), and then slowly increase the value. If no external force is applied, the motor will rotate towards the zero electrical angle position. At this point, test the motor's rotational torque by hand or with a torque meter. When the torque generated by the motor is sufficient to easily rotate the motor shaft, but to avoid damaging the motor... The voltage cannot be too high, according to the voltage limit circle formula for FOC control (geometric boundary theory of SVPWM inverter output voltage):

[0065]

[0066] in, The rated voltage of the motor, when When = 0, | Less than or equal to In this invention, a certain engineering margin is reserved. 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 the motor still fails to generate enough torque to drive the motor shaft to rotate when the voltage exceeds 57% of the rated voltage, the problem should be checked in the motor's drive circuit or whether the friction coefficient of the motor shaft is too high. In practical engineering applications, this invention provides a convenient method to obtain a reasonable... The value, taking a 24V rated voltage motor as an example, can first be calculated as follows: Then increase from 0. The value is displayed, and the motor shaft is manually rotated randomly at the same time, which will generate a certain torque towards the stable point. The direction of rotation is like a compass needle being turned by an external force, eventually pointing south. When the motor shaft already has this tendency to rotate, record this moment. ,For example Then, it can be done using an empirical formula:

[0067] +

[0068] Sure Values, such as those in the examples above. = 8.34V, a reasonable value was obtained by measuring with this setting. Then you can proceed to the next step.

[0069] Step 2: Determine the rotation angle range of the three-phase brushless motor 2, and obtain the maximum and minimum angle values ​​fed back by the angle sensor 3;

[0070] In this embodiment, the range of motor rotation angles is determined, and the maximum and minimum values ​​of the motor angle sensor 3 are read. Because the rotation angle of the motor is limited in this invention, the motor angle sensor 3 also has upper and lower limits. The maximum value of the angle sensor 3 is denoted as A, and the minimum value as B, i.e., ... Figure 3 The upper boundary of the travel of motor A and the lower boundary of the travel of motor B are defined by Z1 and Z2, which are the zero-angle positions of the two motor points, located outside the travel of motor guide rail 1.

[0071] Step 3: Rotate the three-phase brushless motor 2 to near the center of the rotation angle range and start it. Set the electrical angle prediction value to the initial value and detect the feedback value of the angle sensor 3 after the motor rotor stabilizes.

[0072] In this embodiment, during electrical angle zero-point calibration, with the motor powered off, the motor is manually (or automatically driven by another device) rotated to near the center of the rotation range, that is, near the midpoint (A+B) / 2 of the angle reading range. The motor is then started, and the angle is still... Set to 0, voltage Set to Set the estimated electrical angle of the motor. Set the value to zero and observe the stable position of the motor after it rotates. At this point, two situations will occur:

[0073] The first scenario is that the motor's stable position is within its rotational range, specifically the region (A, B). In this case, because... so = .

[0074] The second method involves positioning the motor stably close to the boundary of its rotation range, specifically near the maximum or minimum value (B) of angle sensor 3. At this point, the electrical angle prediction is adjusted. Increase or decrease This value causes the motor's stable position to move away from the boundary of its rotation range and towards the center of its stroke, for example, after passing through... The motor was adjusted to move away from the boundary position and stabilize at point C within its travel range. = Angle sensor 3 reading ,So = - .

[0075] Because of the zero-point calibration value of the electrical angle Based on the feedback value of angle sensor 3 Therefore, the accuracy of angle sensor 3 is directly equal to the calibration accuracy of the electrical angle zero point, as calculated.

[0076] In this embodiment, three-phase motor FOC control is used to adjust the output of the quadrature axis q and the direct axis d, as well as the estimated electrical angle. and the feedback value of motor angle sensor 3 The electrical angle was measured to be zero. In the FOC control of a three-phase motor, the electromagnetic torque equation is:

[0077]

[0078] in, This refers to the electromagnetic torque of the motor. This is the q-axis current; This refers to the d-axis current. It is the extreme logarithm; For permanent magnet flux linkage; It is the q-axis inductance; It is the d-axis inductance.

[0079] Here, the present invention uses the q-axis output voltage Set to 0, d-axis output voltage Set as ,in Greater than zero, therefore we can obtain , = Thus, the electromagnetic torque can be obtained. =0, meaning the motor stator has no torque component output at this time, but there is direct-axis current. = Due to the existence of [something], according to the laws of electromagnetism, the stator of the motor will still generate a magnetic field when [something]. Greater than zero, i.e. - When it is less than zero, at this time This is the "magnetizing" current, which means that the magnetic field generated by the motor stator will attract the magnetic field of the rotor to a position where it is completely aligned with the d-axis (the magnetic fields of the stator and rotor are parallel, and the N pole of the rotor is aligned with the N pole of the stator).

[0080] At this point, without any external force, the motor rotor will remain stationary. To illustrate, the motor rotor is a permanent magnet, like a compass. If this invention does not apply any external force to the compass, its S pole will naturally point to the N pole (geographical south pole). This invention was previously designed with... If the value is less than 0, an external magnetic field similar to the Earth's magnetic field is generated, and =0, meaning the torque perpendicular to the applied magnetic field is zero (no external force is applied), so the S pole of this "compass" will naturally point to the N pole of the applied magnetic field. In this analogy of the invention, the direction of the "geomagnetic field" is generated by the d-axis, and the feedback value (angle sampling value) of the angle sensor 3 in this direction is However, this external magnetic field is rather 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 energization of the stator's three axes (ABC) with an electrical angle of 120° between them (see...). Figure 2 However, this complex combined magnetic field can be transformed into the form of the qd axis using the Clark-Park transformation, and the Clark transformation can be converted into the projection of the ABC axis onto the αβ axis, as shown in the following formula:

[0081]

[0082] The transformation of park into the projection of the αβ axis onto the qd axis is shown in the following formula:

[0083]

[0084] Combining the above formulas Figure 2 This invention provides the estimated electrical angle by finding the angle between the d-axis of the rotating coordinate system and the α-axis (A-axis) of the stationary coordinate system. That is, the stable position of the motor rotor, especially when When = 0, the d-axis directly coincides with the α-axis (A-axis). = , and when When ≠0, the stable position of the motor rotor is: This position is the same as the motor's zero position. The difference is / ,here It refers to the number of pole pairs of the motor, because there is a ratio between the electrical angle value of the motor and the feedback value from the angle sensor 3. For example, if the motor rotates from point A to point B, the angle of rotation fed back by angle sensor 3 is... Then the rotational value of the electrical angle of the motor is Therefore, the formula can be derived from this invention:

[0085] = ( - )

[0086] By shifting the above formula, we get:

[0087] = -

[0088] in, The position of zero electrical angle; This is the estimated value of the electrical angle in FOC control; It is the feedback value from angle sensor 3 after the motor rotor has stabilized; This represents the number of pole pairs of the motor. In this formula, the number of pole pairs is a fixed parameter of the motor. The position of the electrical angle zero point is the feedback position of angle sensor 3 corresponding to the center axis of the A-phase winding of the motor stator. This position is determined after the motor and angle sensor 3 are installed. and All are constant values, thus establishing the present invention. and The correspondence, that is, when Set to 0, Set as At that time, the estimated value of the electric angle Corresponds to the stable position of the motor .

[0089] Step 4: If the feedback value of the angle sensor 3 after stabilization is within the rotation angle range, calculate the zero position of the electrical angle based on the correspondence between the feedback value of the angle sensor 3, the electrical angle prediction value, and the number of pole pairs of the motor.

[0090] If the feedback value of the stabilized angle sensor 3 is at the boundary of the rotation angle range, then adjust the electrical angle prediction value so that the feedback value of the stabilized angle sensor 3 is within the rotation angle range. Then, calculate the electrical angle zero position based on the relationship between the adjusted electrical angle prediction value, the stabilized angle sensor 3 feedback value, and the number of pole pairs of the motor.

[0091] Among them, the electrical angle zero position is the feedback position of angle sensor 3 corresponding to the central axis of the A-phase winding of the motor stator, and the corresponding relationship is as follows:

[0092] The zero electrical angle is equal to the ratio of the stabilized angle sensor 3 feedback value to the electrical angle prediction value and the number of motor pole pairs.

[0093] In this embodiment, for example, a 3600P / R photoelectric encoder has an accuracy of approximately 0.1°. Therefore, the accuracy of the electrical angle zero-point calibration value measured using this invention is also approximately 0.1°. In particular, if a rotary potentiometer-type angle sensor 3 is used for feedback, the accuracy and linearity of the angle feedback value of many rotary potentiometers are better at the center of the rotation range than at the two ends, so it can be adjusted. The value of is such that the shaft is stabilized at the center of the potentiometer's rotation range, at which point the measured electrical angle zero-position calibration value has the highest accuracy.

[0094] In this way, the present invention calibrates the zero position of the electrical angle. In subsequent FOC control, the current electrical angle value of the motor can be calculated using the following formula:

[0095] = ( -

[0096] in, This represents the number of pole pairs of the motor. The current reading of motor angle sensor 3. The zero-position calibration value of the motor's electrical angle is obtained through the previous three steps.

[0097] In summary, under finite angle constraints, the electrical angle zero-point calibration value measured using this invention is more accurate and reliable than the electrical angle zero-point calibration value measured using three-phase pull-in. A comparison is made below using a motor example with a 40-degree rotational stroke constraint, where the stroke range is 10° to 50°. =6, Angle sensor 3 uses a photoelectric encoder with an accuracy of 0.1°, assuming the motor's actual electrical angle is zero. = (5 + 60 × n)°, which is 5°, 65°, 125°, 185°, 245°, and 305°, a total of 6 points. Since the electrical angle zero point appears every 60°, the electrical angle zero point calibration value can be obtained by measuring any of the above points.

[0098] To demonstrate the technical effectiveness of this invention, it is also compared with existing common three-phase high-low level energizing schemes, as shown in Table 1 below:

[0099] Table 1

[0100]

[0101] It can be seen that the present invention stabilizes the rotor within the stroke range by actively adjusting the electrical angle prediction value and calculating the zero position by formula, thus solving the calibration value deviation problem caused by boundary constraints in the traditional high and low level engagement scheme. It has higher accuracy and reliability in scenarios with limited rotation angles.

[0102] Example 2

[0103] Based on the same concept, this invention also proposes a device for zero-position calibration of the electrical angle of a three-phase brushless motor under finite rotation angle constraints, comprising:

[0104] The parameter setting module sets the magnetic field orientation control parameters of the three-phase brushless motor 2, which has feedback from the angle sensor 3 and whose rotation angle is limited to a preset range. The quadrature axis voltage is set to zero and the direct axis voltage is set to a preset negative value.

[0105] The data 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.

[0106] The adjustment module rotates the three-phase brushless motor 2 to near the center of the rotation angle range and then starts it. The electrical angle prediction value is set as the initial value, and the angle sensor feedback value is detected after the motor rotor stabilizes.

[0107] If the feedback value from the angle sensor after stabilization is within the rotation angle range, the judgment module calculates the zero position of the electrical angle based on the correspondence between the angle sensor feedback value, the electrical angle prediction value, and the number of pole pairs of the motor.

[0108] If the feedback value of the angle sensor after stabilization is at the boundary of the rotation angle range, adjust the electrical angle prediction value so that the feedback value of the angle sensor after the motor rotor stabilizes is within the rotation angle range. Then, calculate the electrical angle zero position based on the correspondence between the adjusted electrical angle prediction value, the stable angle sensor feedback value, and the number of motor pole pairs.

[0109] Among them, the electrical angle zero position is the angle sensor feedback position corresponding to the central axis of the A-phase winding of the motor stator, and the corresponding relationship is as follows:

[0110] The zero electrical angle is equal to the ratio of the stabilized angle sensor feedback value to the estimated electrical angle value and the number of pole pairs of the motor.

[0111] Example 3

[0112] This embodiment also provides an electronic device, see reference. Figure 4 It 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.

[0113] Specifically, the processor 402 may include a central processing unit (CPU), or an application-specific integrated circuit (ASIC), or one or more integrated circuits that can be configured to implement embodiments of the present invention.

[0114] Memory 404 may include a mass storage device for data or instructions. For example, and not limitingly, memory 404 may include a hard disk drive (HDD), a floppy disk drive, a solid-state drive (SSD), flash memory, an optical disk drive, a magneto-optical disk drive, 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 a data processing device. In a particular embodiment, memory 404 is non-volatile memory. In a particular embodiment, memory 404 includes read-only memory (ROM) and random access memory (RAM). Where appropriate, the ROM may be a mask-programmed ROM, a programmable read-only memory (PROM), an erasable read-only memory (EPROM), an electrically erasable read-only memory (EEPROM), an electrically alterable read-only memory (EAROM), or flash memory, or a combination of two or more of these. Where appropriate, the RAM can be Static Random-Access Memory (SRAM) or Dynamic Random-Access Memory (DRAM). DRAM can be Fast Page Mode Dynamic Random-Access Memory (FPMDRAM), Extended Data Out Dynamic Random-Access Memory (EDODRAM), Synchronous Dynamic Random-Access Memory (SDRAM), etc.

[0115] The memory 404 can be used to store or cache various data files that need to be processed and / or communicated, as well as possible computer program instructions executed by the processor 402.

[0116] The processor 402 reads and executes computer program instructions stored in the memory 404 to implement any of the methods for zero-position calibration of the electrical angle of a three-phase brushless motor under finite rotation angle constraints in the above embodiments.

[0117] 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.

[0118] The transmission device 406 can be used to receive or send data via a network. Specific examples of the network described above may include wired or wireless networks provided by the communication provider of the electronic device. In one example, the transmission device includes a Network Interface Controller (NIC), which can connect to other network devices via a base station to communicate with the Internet. In another example, the transmission device 406 may be a Radio Frequency (RF) module used for wireless communication with the Internet.

[0119] Input / output device 408 is used to input or output information.

[0120] Example 4

[0121] This embodiment also provides a readable storage medium storing a computer program, which includes program code for controlling a process to execute the process, the process including a method for zero-position calibration of the electrical angle of a three-phase brushless motor under finite angle constraints according to Embodiment 1.

[0122] It should be noted that the specific examples in this embodiment can refer to the examples described in the above embodiments and optional implementations, and will not be repeated here.

[0123] Generally, various embodiments can be implemented in hardware or dedicated circuitry, software, logic, or any combination thereof. Some aspects of the invention can be implemented in hardware, while others can be implemented by 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, flowcharts, or using some other graphical representation, it should be understood that, by way of non-limiting example, these blocks, apparatuses, systems, techniques, or methods described herein can be implemented in hardware, software, firmware, dedicated circuitry or logic, general-purpose hardware or controllers or other computing devices, or some combination thereof.

[0124] Embodiments of the present invention can be implemented by computer software, which may be executable by a data processor of a mobile device, such as 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 can be stored in any device-readable data storage medium, and they include program instructions for performing specific tasks. The computer program product may include one or more computer-executable components configured to perform the embodiments when the program is run. The one or more computer-executable components may be at least one piece of software code or a portion thereof. Additionally, it should be noted in this respect that, as Figure 1 Any box in the logical flow can represent a program step, or interconnected logic circuits, boxes and functions, or a combination of program steps and logic circuits, boxes and functions. Software can be stored on physical media such as memory chips or blocks of storage implemented within a processor, magnetic media such as hard disks or floppy disks, and optical media such as DVDs and their data variants, CDs, etc. The physical medium is a non-transient medium.

[0125] Those skilled in the art should understand that the technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments have been 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.

[0126] The above embodiments are merely illustrative of several implementations of the present invention, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of the present invention should be determined by the appended claims.

Claims

1. A method for zero-position calibration of the electrical angle of a three-phase brushless motor under finite angle constraints, characterized in that, Includes the following steps: Step 1: For a three-phase brushless motor with angle sensor feedback and rotation angle limited to a preset range, set the magnetic field orientation 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 and minimum angle values ​​fed back by the angle sensor; Step 3: Rotate the three-phase brushless motor to the vicinity of the center of the rotation angle range and start it. Set the electrical angle estimate as the initial value and detect 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 zero position of the electrical angle based on the correspondence between the angle sensor feedback value, the electrical angle estimate, 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 prediction value is adjusted so that the stabilized angle sensor feedback value 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 prediction value, the stabilized angle sensor feedback value, and the number of motor pole pairs. Wherein, the electrical angle zero position is the angle sensor feedback position corresponding to the central axis of the A-phase winding of the motor stator, and the correspondence is as follows: The zero electrical angle is equal to the ratio of the stabilized angle sensor feedback value to the estimated electrical angle value and the number of pole pairs of the motor.

2. The method for zero-position calibration of the electrical angle of a three-phase brushless motor under finite rotation angle constraints as described in claim 1, characterized in that, In step 1, the absolute value of the preset negative value of the direct shaft voltage is the 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 finite rotation angle constraints as described in claim 2, characterized in that, The determination of the preset voltage value includes: gradually increasing the voltage value from the 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 finite angle constraints as described in claim 1, characterized in that, In step 3, the initial value of the electrical angle estimate is zero.

5. The method for zero-position calibration of the electrical angle of a three-phase brushless motor under finite rotation angle constraints as described in claim 1, characterized in that, In step 4, the method for adjusting the electrical angle estimate is as follows: Increase or decrease the electrical angle prediction value so that the angle sensor feedback value after the motor rotor stabilizes moves towards the center of the rotation angle range.

6. The method for zero-position calibration of the electrical angle of a three-phase brushless motor under finite angle constraints as described in claim 1, characterized in that, In step 1, the magnetic field orientation control achieves the mapping between 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 direction of the magnetic field 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 finite angle constraints as described in any one of claims 1 to 6, characterized in that, The rotation angle within the preset range is less than the ratio of 360° to the number of pole pairs of the motor.

8. A device for zero-position calibration of the electrical angle of a three-phase brushless motor under finite rotation angle constraints, characterized in that, include: The parameter setting module sets the magnetic field orientation control parameters of a three-phase brushless motor that has angle sensor feedback and whose rotation angle is limited to a preset range. Among them, the quadrature axis voltage is set to zero and the direct axis voltage is set to a preset negative value. The data 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 electrical angle prediction value is set as the initial value, and the angle sensor feedback value is detected after the motor rotor stabilizes. If the feedback value from the angle sensor after stabilization is within the rotation angle range, the judgment module calculates the zero position of the electrical angle based on the correspondence between the angle sensor feedback value, the electrical angle prediction value, and the number of pole pairs of the motor. If the feedback value of the angle sensor after stabilization is at the boundary of the rotation angle range, adjust the electrical angle prediction value so that the feedback value of the angle sensor after the motor rotor stabilizes is within the rotation angle range. Then, calculate the electrical angle zero position based on the correspondence between the adjusted electrical angle prediction value, the stable angle sensor feedback value, and the number of motor pole pairs. Among them, the electrical angle zero position is the angle sensor feedback position corresponding to the central axis of the A-phase winding of the motor stator, and the corresponding relationship is as follows: The zero electrical angle is equal to the ratio of the stabilized angle sensor feedback value to the estimated electrical angle value and the number of pole pairs of the motor.

9. An electronic device comprising a memory and a processor, characterized in that, The memory stores a computer program, and the processor is configured to run the computer program to perform the method for zero-position calibration of the electrical angle of a three-phase brushless motor under finite angle constraints as described in any one of claims 1 to 7.

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

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