Outer rotor permanent magnet synchronous motor encoder data correction method and device

Abstract

The invention discloses an outer rotor permanent magnet synchronous motor encoder data correction method and device, and aims to solve the problem of poor precision of encoder position detection of an existing outer rotor permanent magnet synchronous motor. The method comprises the following steps: acquiring a current motor position and a motor position in a previous sampling period through an encoder to obtain a first position increment; estimating the current rotating speed of the motor according to the output current of the permanent magnet synchronous motor; obtaining a second position increment according to the current motor rotating speed and the sampling period; and comparing the first position increment with the second position increment to judge whether the data collected by the encoder is abnormal or not, and correcting the abnormal data. The method is simple and reliable, the requirement for the encoder installation process is low, abnormal data errors caused by encoder installation errors or noise interference can be eliminated, the accuracy of encoder detection data is effectively guaranteed, and the stability of closed-loop vector control of the permanent magnet synchronous motor is effectively improved.

Description

Technical Field

[0001] The present application relates to the field of motor control, and particularly to a method and device for correcting encoder data of an outer-rotor permanent magnet synchronous motor. Background Art

[0002] In recent years, direct-drive permanent magnet synchronous motors have been widely promoted and applied in many industrial fields due to their high power factor, high efficiency, large starting torque and other characteristics. Among them, outer-rotor permanent magnet synchronous motors are widely used in belt conveyors, scraper conveyors, crushers and other fields by reducing auxiliary drive components such as intermediate shafts and chains, and by virtue of advantages such as small volume, small axial dimension, and good system operation stability.

[0003] The stator of the outer-rotor permanent magnet synchronous motor is fixed in the middle position of the shaft without moving, and a drum is sleeved outside the rotor. The rotor rotates around the stator, so it is also called a permanent magnet electric drum. Generally speaking, the permanent magnets of the outer-rotor motor are embedded in the rotating outer-rotor part, while the coil windings do not rotate inside, which makes it difficult to install conventional small-aperture encoders.

[0004] At present, when installing an encoder for a high-power outer-rotor permanent magnet synchronous motor, there are usually two methods. One is to use a customized large-aperture encoder, but this method is still limited by the internal customized shaft size, and has disadvantages such as poor versatility, high maintenance difficulty, and high customization cost. The other is a mechanical structure with non-concentric rotation of two or more sets of gear devices. This method has low cost, convenient installation, and strong versatility, and is a common motor speed measurement method. However, due to the inevitable mechanical clearance in the processing and installation of the gear device, and the encoder is not concentrically installed with the motor shaft, there is a mechanical position error in this method, which will affect the accuracy of motor position detection and it is difficult to achieve high-performance closed-loop vector control of the permanent magnet synchronous motor. Summary of the Invention

[0005] Embodiments of the present application provide a method and device for correcting encoder data of an outer-rotor permanent magnet synchronous motor to solve the problem of poor accuracy of encoder position detection of the existing outer-rotor permanent magnet synchronous motor.

[0006] A method for correcting encoder data of an outer-rotor permanent magnet synchronous motor provided by an embodiment of the present application includes: Collecting the current motor position and the motor position in the previous sampling period through an encoder to obtain a first position increment; Estimating the current motor speed according to the output current of the permanent magnet synchronous motor; Obtaining a second position increment according to the current motor speed and the sampling period; Judging whether the data collected by the encoder is abnormal by comparing the first position increment and the second position increment, and correcting the abnormal data.

[0007] In one example, the current motor speed is estimated based on the output current of the permanent magnet synchronous motor, specifically including: collecting the output current of the permanent magnet synchronous motor, and obtaining the direct-axis current and the quadrature-axis current through coordinate transformation; determining the estimated value of the direct-axis current and the estimated value of the quadrature-axis current according to the direct-axis current, the quadrature-axis current, and the motor speed in the previous sampling period; and estimating the current motor speed according to the estimated value of the direct-axis current and the estimated value of the quadrature-axis current.

[0008] In one example, collecting the output current of the permanent magnet synchronous motor, obtaining the direct-axis current and the quadrature-axis current through coordinate transformation, and determining the estimated value of the direct-axis current and the estimated value of the quadrature-axis current according to the direct-axis current, the quadrature-axis current, and the motor speed in the previous sampling period specifically include: within the sampling period, calculating the estimated value of the direct-axis current according to the influence of the motor stator resistance, the direct-axis inductance, the quadrature-axis inductance, the motor speed in the previous sampling period, and the direct-axis voltage on the direct-axis current and the quadrature-axis current; and within the sampling period, calculating the estimated value of the quadrature-axis current according to the influence of the motor stator resistance, the direct-axis inductance, the quadrature-axis inductance, the motor speed in the previous sampling period, the permanent magnet flux linkage, and the quadrature-axis voltage on the direct-axis current and the quadrature-axis current.

[0009] In one example, determining the current motor speed according to the estimated value of the direct-axis current and the estimated value of the quadrature-axis current specifically includes: through a PI controller, estimating the current motor speed according to the initial motor speed, the differential operator, the proportional term gain, the integral term gain, the direct-axis current, the quadrature-axis current, the estimated value of the direct-axis current, and the estimated value of the quadrature-axis current.

[0010] In one example, obtaining a second position increment according to the current motor speed and the sampling period specifically includes: setting an increment limit coefficient; wherein, the magnitude of the increment limit coefficient is negatively correlated with the detection sensitivity to abnormal data; multiplying the estimated current motor speed, the sampling period, and the increment limit coefficient to obtain the second position increment.

[0011] In one example, by comparing the first position increment and the second position increment, it is determined whether the data collected by the encoder is abnormal, specifically including: when the first position increment is less than the second position increment, determining that the data collected by the encoder is normal; when the first position increment is greater than or equal to the second position increment, determining that the data collected by the encoder is abnormal.

[0012] In one example, the method further includes: when the data collected by the encoder is normal, calculating the actual current motor speed according to the first position increment and the sampling period; and outputting the current motor position and the actual current motor speed collected by the encoder.

[0013] In one example, correcting abnormal data specifically includes: calculating the normal current motor position based on the estimated current motor speed, the sampling period, and the motor position in the previous sampling period; and outputting the normal current motor position and the estimated current motor speed.

[0014] In one example, after outputting the current motor position and the current motor speed, the method further includes: under closed-loop vector control, obtaining the current command value of the current-loop controller based on the current motor speed; performing coordinate transformation according to the current motor position to transform the three-phase current into the current and voltage in the d-q coordinate system, and then performing coordinate transformation again to obtain the three-phase modulation voltage; and controlling the inverter to generate the target voltage through carrier phase-shifted pulse width modulation to drive the outer-rotor permanent magnet synchronous motor.

[0015] An outer-rotor permanent magnet synchronous motor encoder data correction device provided by an embodiment of the present application includes: An acquisition module that acquires the current motor position and the motor position in the previous sampling period through an encoder to obtain a first position increment; An estimation module that estimates the current motor speed according to the output current of the permanent magnet synchronous motor; A calculation module that obtains a second position increment according to the current motor speed and the sampling period; A correction module that determines whether the data acquired by the encoder is abnormal by comparing the first position increment and the second position increment, and corrects the abnormal data.

[0016] An outer-rotor permanent magnet synchronous motor encoder data correction method and device provided by an embodiment of the present application can achieve the following beneficial effects: Detecting the motor position sequence through the encoder, determining whether there is an abnormality based on the detected position increment, and online correcting and compensating the detected abnormal data by estimating the motor speed, so as to accurately identify and compensate the sampling interference of the encoder, eliminate the abnormal data errors caused by encoder installation errors or noise interference, which is simple and reliable, has low requirements for the encoder installation process, is especially suitable for the occasions where the encoder installation error of the outer-rotor permanent magnet synchronous motor is large, can effectively guarantee the accuracy of the encoder detection data, has strong robustness to encoder data disturbances, and effectively improves the stability of the closed-loop vector control of the permanent magnet synchronous motor. Description of the Drawings

[0017] To more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. The drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation to the present application. In the drawings: Figure 1 It is a flowchart of a method for correcting encoder data of an outer-rotor permanent magnet synchronous motor provided by an embodiment of the present application; Figure 2 It is a flowchart of another method for correcting encoder data of an outer-rotor permanent magnet synchronous motor provided by an embodiment of the present application; Figure 3 It is a schematic diagram of vector control of an outer-rotor permanent magnet synchronous motor provided by an embodiment of the present application; Figure 4 It is a schematic structural diagram of a device for correcting encoder data of an outer-rotor permanent magnet synchronous motor provided by an embodiment of the present application. Detailed implementation manners

[0018] To make the objectives, technical solutions, and advantages of the present application clearer, the following will clearly and completely describe the technical solutions of the present application in conjunction with the specific embodiments of the present application and the corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application.

[0019] In an outer-rotor permanent magnet synchronous motor, the encoder real-time monitors the mechanical angle and rotational speed of the motor rotor. By analyzing the precise position of the rotor in the d-q coordinate system, the controller can accurately decompose the direct-axis / quadrature-axis currents, achieve the decoupling control of torque and magnetic field, improve the motor efficiency, and realize the spatial synchronization of the armature current vector and the rotor magnetic field, providing closed-loop feedback for the controller. It is the core feedback component of closed-loop control. Therefore, the accuracy of encoder position detection is the key to achieving high-performance vector control of permanent magnet synchronous motors.

[0020] Figure 1 It is a flowchart of a method for correcting encoder data of an outer-rotor permanent magnet synchronous motor provided by an embodiment of the present application, specifically including the following steps: S101: Collect the current motor position and the motor position in the previous sampling period through the encoder to obtain the first position increment.

[0021] In the embodiment of the present application, the encoder collects data at a set sampling period. The collected data may include the motor position (i.e., the rotor position angle), the rotation direction, the zero position signal, etc. Here, the accuracy of the motor position is mainly detected and abnormally corrected.

[0022] Among them, the sampling period can be determined according to factors such as the type of encoder, resolution, and motor speed.

[0023] During the rotation of the motor, based on the current motor position collected by the encoder and the motor position in the previous sampling period, the angle passed by the motor rotation can be obtained as the first position increment. Specifically, it can be expressed by the following formula (1): Δ θ k = θ k - θ k-1 Formula (1) Among them, Δ θ k represents the first position increment, θ k represents the current motor position, θ k-1 represents the motor position in the previous sampling period.

[0024] S102: Estimate the current motor speed according to the output current of the permanent magnet synchronous motor.

[0025] In the embodiment of the present application, in order to check whether the data of the motor position collected by the encoder is accurate, other data can be collected to estimate the motor position, and the estimated data is compared with the collected data to determine whether the data collected by the encoder is abnormal.

[0026] Specifically, the current motor speed can be estimated according to the output current of the permanent magnet synchronous motor, and the motor position can be further estimated through the estimated motor speed.

[0027] In one embodiment, estimating the current motor speed mainly includes the following three steps: First, collect the output current of the permanent magnet synchronous motor, and obtain the direct-axis current and quadrature-axis current through coordinate transformation.

[0028] Specifically, the values of the three-phase current are measured in real time through devices such as current sensors, and the direct-axis current and quadrature-axis current in the d-q coordinate system are obtained through coordinate transformations such as Clarke transformation and Park transformation.

[0029] Second, determine the direct-axis current estimated value and the quadrature-axis current estimated value according to the direct-axis current, quadrature-axis current, and the motor speed in the previous sampling period.

[0030] Specifically, within the sampling period, an estimated value of the direct-axis current is calculated based on the stator resistance of the motor, the direct-axis inductance, the quadrature-axis inductance, the motor speed in the previous sampling period, and the influence of the direct-axis voltage on the direct-axis current and the quadrature-axis current; and, within the sampling period, an estimated value of the quadrature-axis current is calculated based on the stator resistance of the motor, the direct-axis inductance, the quadrature-axis inductance, the motor speed in the previous sampling period, the permanent magnet flux linkage, and the influence of the quadrature-axis voltage on the direct-axis current and the quadrature-axis current.

[0031] Specifically, it can be represented by the following formula two corresponding to the motor mathematical model: Formula Two Wherein, is the estimated value of the direct current, is the estimated value of the quadrature-axis current, i d is the direct-axis current, i q is the quadrature-axis current, u d is the direct-axis voltage, u q is the quadrature-axis voltage, R s is the stator resistance of the motor, L d is the direct-axis inductance of the motor, L q is the quadrature-axis inductance of the motor, Ψ f is the permanent magnet flux linkage, T s is the sampling period, is the estimated motor speed calculated in the previous sampling period.

[0032] Third, based on the estimated value of the direct-axis current and the estimated value of the quadrature-axis current, the current motor speed is estimated.

[0033] Specifically, through a Proportion Integration (PI) controller, based on the initial motor speed, the differential operator, the proportional term gain, the integral term gain, the direct-axis current, the quadrature-axis current, the estimated value of the direct-axis current, and the estimated value of the quadrature-axis current, the current motor speed is estimated.

[0034] The PI controller is the core module of the closed-loop control system. It can accumulate historical errors through the integral term (I), force the system output to converge to the target value, eliminate the steady-state error, and can also quickly respond to error changes through the proportional term (P), shorten the adjustment time, and achieve dynamic response regulation. Therefore, the PI controller is commonly used in motor control to adjust the operating state of the motor.

[0035] Specifically, it can be represented by the following formula three based on the model reference adaptive system: Formula Three Wherein, is the estimated motor speed calculated for the current sampling period, k p is the proportional term gain of the PI controller, k i is the integral term gain of the PI controller, s is the differential operator, 1 / s represents integration, is the estimated value of the direct current, is the estimated value of the quadrature-axis current, i d is the direct-axis current, i q is the quadrature-axis current, L s is the motor inductance, Ψ f is the permanent magnet flux linkage, is the initial speed of the permanent magnet synchronous motor.

[0036] In one embodiment, based on the initial motor speed of the permanent magnet synchronous motor, the estimated value of the direct-axis current and the estimated value of the quadrature-axis current are calculated through the second step, and then the current motor speed is calculated according to the estimated value of the direct-axis current and the estimated value of the quadrature-axis current in the third step, so as to realize the numerical iterative update of the motor speed, and be applied to the second step of subsequent motor speed calculation work.

[0037] S103: Obtain the second position increment according to the current motor speed and the sampling period.

[0038] In the embodiment of the present application, after calculating the current motor speed, multiplying the current motor speed by the sampling period can obtain the rotation angle passed by the motor in one sampling period, which is used as the second position increment.

[0039] In one embodiment, when calculating the second position increment, the increment limit coefficient can be set according to the detection sensitivity requirement for abnormal data, and the estimated current motor speed, sampling period, and increment limit coefficient are multiplied, and the obtained result is used as the second position increment.

[0040] It should be noted that based on the fact that the current motor speed is an estimated value, therefore, by setting the increment limit coefficient, the second position increment can be allowed to vary within a certain small range to eliminate the influence of unavoidable errors.

[0041] Among them, the magnitude of the increment limit coefficient is negatively correlated with the detection sensitivity of abnormal data. The larger the increment limit coefficient, the larger the second position increment, and the larger the allowable error range. When comparing the second position increment with the first position increment later, the abnormal detection of the first position increment is more lenient, resulting in the easy omission of abnormal data. When the increment limit coefficient is infinite, abnormal data cannot even be detected. On the contrary, the smaller the increment limit coefficient, the smaller the second position increment, and the smaller the allowable normal error range. When comparing the second position increment with the first position increment later, the abnormal detection of the first position increment is too strict, and even normal data is difficult to pass the detection, making normal data also be detected as abnormal data.

[0042] Therefore, when setting the increment limit coefficient, an appropriate range needs to be determined. Within the appropriate range, when the detection sensitivity requirement for abnormal data is high, the increment limit coefficient can be set smaller; when the detection sensitivity requirement for abnormal data is low, the increment limit coefficient can be set larger.

[0043] In one embodiment, the increment limit coefficient needs to be greater than 1, and its appropriate range is greater than 1 and less than 5. For example, setting the increment limit coefficient to 3 can effectively detect abnormal data while ensuring the detection accuracy and maintaining an appropriate detection sensitivity.

[0044] Specifically, the calculation of the second position increment can be represented by the following formula four: Formula Four where k represents the increment limit coefficient, is the estimated motor speed calculated for the current sampling period, T s is the sampling period, δ max represents the second position increment, that is, the maximum value of the increment limit.

[0045] S104: By comparing the first position increment and the second position increment, determine whether the data collected by the encoder is abnormal and correct the abnormal data.

[0046] In the embodiment of the present application, the first position increment represents the motor position data collected by the encoder, the second position increment represents the motor position data estimated by collecting other data, and the second position increment delimits a reasonable fluctuation range for the first position increment by setting the increment limit coefficient, that is, the value of the second position increment is the maximum value allowed for fluctuation.

[0047] Therefore, when comparing two pieces of data, if the first position increment is within the range of the second position increment, it indicates that the first position increment is normal data and the data collected by the encoder is accurate; if the first position increment is not within the range of the second position increment, it indicates that the second position increment is abnormal data, the data collected by the encoder is incorrect, and correction is required.

[0048] Specifically, when comparing the first position increment and the second position increment, when the first position increment is less than the second position increment, it is determined that the data collected by the encoder is normal; when the first position increment is greater than or equal to the second position increment, it is determined that the data collected by the encoder is abnormal.

[0049] In one embodiment, if it is determined that the data collected by the encoder is normal, the data of the first position increment is accurate. According to the first position increment and the sampling period, the two can be divided to calculate the actual current motor speed, and the current motor position collected by the encoder and the calculated actual current motor speed are output for use by the motor.

[0050] Specifically, this process can be represented by the following formula five: Formula Five where, Δ θ k represents the first position increment, δ max represents the second position increment, θ k represents the current motor position, T s is the sampling period.

[0051] In one embodiment, if it is determined that the data collected by the encoder is abnormal, the first position increment cannot be adopted. The estimated current motor speed can be used as accurate data, and based on the estimated current motor speed, the sampling period, and the motor position in the previous sampling period, the normal and accurate current motor position is calculated to correct the abnormal data. After correction, the normal current motor position and the estimated current motor speed can be output for use by the motor.

[0052] Specifically, the correction process can be represented by the following formula six: Formula Six where, Δ θ k represents the first position increment, δ max represents the second position increment, θ k-1 represents the motor position in the previous sampling period, The estimated motor speed calculated for the current sampling period T s is the sampling period

[0053] In one embodiment, after outputting the correct current motor position and current motor speed, under closed-loop vector control, according to the current motor speed, the current command value of the current loop controller can be obtained through the speed loop controller; according to the current motor position, coordinate transformation is performed to transform the three-phase current into the current and voltage in the d-q coordinate system, and then coordinate transformation is performed again to obtain the three-phase modulation voltage; through carrier phase-shifted pulse width modulation, the inverter is controlled to generate the target voltage to drive the outer-rotor permanent magnet synchronous motor

[0054] In the embodiment of the present application, the motor position sequence is detected by the encoder, whether there is an abnormality is judged according to the detected position increment, and the detected abnormal data is corrected and compensated online by estimating the motor speed, so as to eliminate the abnormal data error caused by encoder installation error or noise interference. This method is simple and reliable, has low requirements for the encoder installation process, can effectively ensure the accuracy of the encoder detection data, and effectively improve the stability of the closed-loop vector control of the permanent magnet synchronous motor

[0055] Figure 2 It is a flowchart of another encoder data correction method for the outer-rotor permanent magnet synchronous motor provided by the embodiment of the present application

[0056] As Figure 2 shown, the encoder collects the current motor position θ k and the motor position of the previous sampling period θ k-1 , and subtracts them to obtain the first position increment Δ θ k ; the motor speed is estimated through the speed observer to obtain the estimated motor speed ; an increment limit coefficient k is set, and the increment limit δ max is calculated according to k, that is, the second position increment, where k > 1; compare the first position increment Δ θ k with the second position increment δ max , if the first position increment is less than the second position increment, it means that the encoder data is normal, and the current motor position θ k detected by the encoder can be output, and according to the first position increment Δ θ k and the sampling period T sCalculate the current motor speed and output the current motor speed as well; if the first position increment is not less than the second position increment, it indicates that the encoder data is abnormal. Correct the abnormal data, use the estimated motor speed as the correct data, and based on the estimated motor speed , sampling period T s , the motor position in the previous sampling period θ k-1 Calculate the current motor position and output the calculated current motor position and the estimated motor speed.

[0057] In this application, based on the motor position sequence detected by the encoder, it is judged whether there is an abnormality according to the detected position increment. If there is an abnormal position detection, the online correction and compensation of the detected abnormal information are carried out through the permanent magnet synchronous motor speed observer, compensate the abnormal position, and eliminate the abnormal data error caused by the encoder installation error or noise interference. This is simple and reliable, has low requirements for the encoder installation process, and can effectively improve the stability of the permanent magnet synchronous motor closed-loop vector control.

[0058] Figure 3 It is a schematic diagram of the vector control of the outer rotor permanent magnet synchronous motor provided by the embodiment of this application.

[0059] In a possible implementation manner, as Figure 3 shown, the high-voltage inverter includes three power units A1~A5, B1~B5, and C1~C5. According to the output three-phase current i a 、i b 、i c , after coordinate transformation, it becomes the direct-axis current i d and the quadrature-axis current i q in the d-q coordinate system; through the PI controller, the speed observer estimates the current motor speed i d and the quadrature-axis current i q ; the encoder is connected to the permanent magnet synchronous motor (PMSM), and the current motor position is obtained through position detection θ k and the motor position in the previous sampling period θ k-1; Input the current motor speed estimated by the speed observer into the encoder position correction compensation and speed calculation module to calculate the second position increment and perform anomaly detection. After detecting abnormal data, perform correction compensation to determine the correct motor position. θ and the motor speed ω Output. According to the output motor position θ , transform it into three-phase modulated voltage through coordinate transformation, and then through carrier phase-shifted pulse width modulation, control the inverter to generate the target voltage to drive the outer-rotor permanent magnet synchronous motor.

[0060] The above is the method for correcting encoder data of an outer-rotor permanent magnet synchronous motor provided by the embodiments of the present application. Based on the same inventive concept, the embodiments of the present application also provide a corresponding device for correcting encoder data of an outer-rotor permanent magnet synchronous motor, as Figure 4 shown.

[0061] Figure 4 is a schematic structural diagram of the device for correcting encoder data of an outer-rotor permanent magnet synchronous motor provided by the embodiments of the present application, specifically including: Acquisition module 401, which acquires the current motor position and the motor position in the previous sampling period through the encoder to obtain the first position increment; Estimation module 402, which estimates the current motor speed according to the output current of the permanent magnet synchronous motor; Calculation module 403, which obtains the second position increment according to the current motor speed and the sampling period; Correction module 404, which determines whether the data acquired by the encoder is abnormal by comparing the first position increment and the second position increment, and corrects the abnormal data.

[0062] It should be understood that each part disclosed in the present application can be implemented by hardware, software, firmware, or a combination thereof. In the description of the above embodiments, specific features, structures, materials, or characteristics can be combined in a suitable manner in any one or more embodiments or examples.

[0063] The embodiments in the present application are all described in a progressive manner. The same or similar parts among the embodiments can be referred to each other, and each embodiment focuses on the differences from other embodiments. In particular, for the device embodiments, since they are basically similar to the method embodiments, the description is relatively simple, and the relevant parts can refer to the partial description of the method embodiments.

[0064] The device provided by the embodiments of the present application corresponds one-to-one with the method. Therefore, the device also has beneficial technical effects similar to those of the corresponding method. Since the beneficial technical effects of the method have been described in detail above, the beneficial technical effects of the device will not be elaborated here.

[0065] The flow chart and block diagram in the accompanying drawings illustrate the possible architecture, function and operation of the system, method and computer program product according to various embodiments of the present application. In this regard, each square box in the flow chart or block diagram can represent a module, a program segment or a part of a code, and the module, the program segment or a part of the code contains one or more executable instructions for realizing the specified logical function. It should also be noted that in some alternative implementations, the functions marked in the square box can also occur in a sequence different from that marked in the accompanying drawings. For example, two square boxes represented in succession can actually be executed substantially in parallel, and they can sometimes be executed in the opposite order, depending on the functions involved. It should also be noted that each square box in the block diagram and / or flow chart, and the combination of the square boxes in the block diagram and / or flow chart can be implemented with a dedicated hardware-based system that performs a specified function or operation, or can be implemented with a combination of dedicated hardware and computer instructions.

[0066] The modules involved in the embodiments described in this application may be implemented by software or hardware, wherein the name of the module does not constitute a limitation on the unit itself in some cases.

[0067] It should also be noted that the terms "include", "comprises" or any other variations thereof are intended to cover non-exclusive inclusion, so that a process, method, commodity or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, commodity or device. In the absence of more restrictions, the elements defined by the sentence "comprises a ..." do not exclude the existence of other identical elements in the process, method, commodity or device including the elements.

[0068] The above is only an embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various changes and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the scope of the claims of the present application.

Claims

1. A method for correcting encoder data of an outer rotor permanent magnet synchronous motor, characterized in that: include: The encoder collects the current motor position and the motor position in the previous sampling period to obtain a first position increment; estimating a current motor speed according to an output current of the permanent magnet synchronous motor; Obtaining a second position increment according to the current motor speed and the sampling period; By comparing the first position increment and the second position increment, it is determined whether the data collected by the encoder is abnormal, and the abnormal data is corrected.

2. The outer rotor permanent magnet synchronous motor encoder data correction method according to claim 1, characterized in that: According to the output current of the permanent magnet synchronous motor, the current motor speed is estimated, specifically including: Collecting the output current of the permanent magnet synchronous motor, and obtaining the direct-axis current and the quadrature-axis current through coordinate transformation; Determine a direct-axis current estimate value and a quadrature-axis current estimate value according to the direct-axis current, the quadrature-axis current, and the motor speed in the previous sampling period; The current motor speed is estimated according to the direct-axis current estimation value and the quadrature-axis current estimation value.

3. The outer rotor permanent magnet synchronous motor encoder data correction method according to claim 2, characterized in that: The output current of the permanent magnet synchronous motor is collected, a direct-axis current and a quadrature-axis current are obtained by coordinate transformation, and a direct-axis current estimation value and a quadrature-axis current estimation value are determined according to the direct-axis current, the quadrature-axis current, and the motor speed in the previous sampling period, specifically including: In the sampling period, the direct-axis current estimation value is calculated according to the influence of the motor stator resistance, direct-axis inductance, quadrature-axis inductance, motor speed in the previous sampling period, and direct-axis voltage on the direct-axis current and quadrature-axis current; In the sampling period, the quadrature-axis current estimation value is calculated according to the influence of the motor stator resistance, direct-axis inductance, quadrature-axis inductance, motor speed in the previous sampling period, permanent magnet flux linkage, and quadrature-axis voltage on the direct-axis current and quadrature-axis current.

4. The outer rotor permanent magnet synchronous motor encoder data correction method according to claim 2, characterized in that: Determining the current motor speed according to the direct-axis current estimation value and the quadrature-axis current estimation value specifically includes: The current motor speed is estimated through the PI controller according to the initial motor speed, differential operator, proportional gain, integral gain, direct-axis current, quadrature-axis current, direct-axis current estimated value, and quadrature-axis current estimated value.

5. The outer rotor permanent magnet synchronous motor encoder data correction method according to claim 1, characterized in that: Obtaining a second position increment according to the current motor speed and the sampling period specifically includes: Set the incremental limit coefficient; the incremental limit coefficient is negatively correlated with the sensitivity of detecting abnormal data; The estimated current motor speed, sampling period, and increment limit coefficient are multiplied to obtain a second position increment.

6. The outer rotor permanent magnet synchronous motor encoder data correction method according to claim 1, characterized in that: By comparing the first position increment and the second position increment, determining whether the data collected by the encoder is abnormal specifically includes: When the first position increment is less than the second position increment, it is determined that the data collected by the encoder is normal; When the first position increment is greater than or equal to the second position increment, it is determined that the data collected by the encoder is abnormal.

7. The outer rotor permanent magnet synchronous motor encoder data correction method according to claim 1, characterized in that: The method further comprises: When the data collected by the encoder is normal, the actual current motor speed is calculated according to the first position increment and the sampling period; The current motor position and the actual current motor speed acquired by the encoder are output.

8. The outer rotor permanent magnet synchronous motor encoder data correction method according to claim 1, characterized in that: Correct abnormal data, including: Calculate the normal current motor position according to the estimated current motor speed, the sampling period, and the motor position in the previous sampling period; The normal current motor position and the estimated current motor speed are output.

9. The outer rotor permanent magnet synchronous motor encoder data correction method according to any one of claims 7 or 8, characterized in that: After outputting the current motor position and the current motor speed, the method further includes: Under closed-loop vector control, the current command value of the current loop controller is obtained through the speed loop controller according to the current motor speed; According to the current motor position, coordinate transformation is performed to transform the three-phase current into the current and voltage in the dq coordinate system, and then coordinate transformation is performed again into the three-phase modulated voltage; The inverter is controlled to generate a target voltage through carrier phase-shift pulse width modulation to drive the outer rotor permanent magnet synchronous motor.

10. An outer rotor permanent magnet synchronous motor encoder data correction device, characterized in that: include: The acquisition module acquires the current motor position and the motor position in the previous sampling period through the encoder to obtain the first position increment; An estimation module estimates the current motor speed according to the output current of the permanent magnet synchronous motor; A calculation module, obtaining a second position increment according to the current motor speed and the sampling period; The correction module determines whether the data collected by the encoder is abnormal by comparing the first position increment and the second position increment, and corrects the abnormal data.

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