Rotor position calibration method and device and storage medium

Abstract

The invention discloses a rotor position calibration method and device and a storage medium, and the method and device are used for a permanent magnet synchronous motor, and the method comprises the steps: determining the theoretical position of a target point on a rotor of the motor at a periodic time point for a target rotating speed according to a preset target rotating speed; determining a target driving force according to the target rotating speed, applying the target driving force to the rotor to enable the rotor to rotate, and monitoring the real position of the target point at the periodic time point in real time; determining position errors at a plurality of time points in a preset measurement period according to the theoretical position and the real position; an error curve is determined based on the position error, and the rotor position is calibrated based on the error curve. According to the technical scheme provided by the invention, the technical problem of motor torque fluctuation caused by the fact that the rotor position signal is possibly nonlinear in the operation process of the permanent magnet synchronous motor in the prior art can be solved, the rotor position can be calibrated, and the accurate rotor position signal can be obtained in real time.

Description

Rotor position calibration method, device and storage medium Technical Field

[0001] The present invention relates to the technical field of permanent magnet synchronous motors, and in particular to a rotor position calibration method, device and storage medium. Background Art

[0002] Permanent magnet synchronous motors (PMSMs) are AC motors that use permanent magnets for excitation. This simplifies the motor structure, reduces processing and assembly costs, and improves operational reliability. Because they require no excitation current and eliminate excitation losses, they improve efficiency and power density, making them increasingly widely used across various fields.

[0003] During the effective operation of a permanent magnet synchronous motor, it is necessary to obtain accurate rotor position signals in real time to ensure that the motor outputs stable alternating current. The rotor position signals are usually collected by sensors. When the motor components are improperly installed or age with use, the rotor position signals will become nonlinear, causing motor torque fluctuations, seriously affecting the normal use of the product. The existing technical means is to perform compensation and calibration on the permanent magnet synchronous motor test bench to correct the nonlinear phenomenon during the motor's offline process. This solution relies on workbench resources and requires that the position signal sensor in the workbench is very accurate. Therefore, in the existing technology, the effect of rotor position compensation and correction depends on the performance of the workbench, and the calibration scenario is also relatively fixed, which is not suitable for permanent magnet synchronous motors in application scenarios.

[0004] Summary of the Invention

[0005] The present invention provides a rotor position calibration method, device and storage medium, aiming to effectively solve the technical problem in the prior art that the rotor position signal of a permanent magnet synchronous motor may be nonlinear during operation, resulting in motor torque fluctuations. The method can calibrate the rotor position and obtain a real-time and accurate rotor position signal.

[0006] According to one aspect of the present invention, the present invention provides a rotor position calibration method for a permanent magnet synchronous motor, the method comprising:

[0007] Determining, according to a preset target speed, a theoretical position of a target point on the rotor of the motor at a periodic time point for the target speed;

[0008] determining a target driving force according to the target rotational speed, applying the target driving force to the rotor to rotate the rotor, and monitoring in real time the actual position of the target point at the periodic time point;

[0009] determining position errors at multiple time points within a preset measurement period according to the theoretical position and the actual position;

[0010] An error curve is determined based on the position error, and the rotor position is calibrated based on the error curve.

[0011] Furthermore, determining the theoretical position of a target point on the rotor of the motor at a periodic time point for the target speed according to a preset target speed includes:

[0012] The theoretical rotation angle of the rotor is obtained according to the operating time of the target point and the target rotation speed, and the theoretical position is obtained according to the theoretical rotation angle and the initial position of the rotor.

[0013] Furthermore, determining the target driving force according to the target speed includes:

[0014] The target driving force is determined based on a field oriented control method and the theoretical position corresponding to the target speed.

[0015] Furthermore, the determining the target driving force based on the magnetic field oriented control method and the theoretical position corresponding to the target speed includes:

[0016] A current motor current of the motor is acquired, a duty cycle of the motor is determined according to the motor current and the theoretical position, and the target driving force is determined based on the duty cycle.

[0017] Furthermore, the real-time monitoring of the actual position of the target point at the periodic time point includes:

[0018] The actual position of the target point at the periodic time point is monitored by a magnetoelectric position sensor.

[0019] Furthermore, determining the position errors at multiple time points within a preset measurement period according to the theoretical position and the actual position includes:

[0020] Determining the number of rotation periods of the rotor within the preset measurement period and a sampling sequence for sampling the position error within one rotation period, wherein the sampling sequence corresponds to the periodic time points in a one-to-one correspondence;

[0021] For each rotation period within the preset measurement period, position errors at multiple time points within the rotation period are determined based on the sampling sequence, the theoretical position, and the actual position.

[0022] Furthermore, determining an error curve based on the position error includes:

[0023] A position error mean value of each sampling sequence in the sampling sequences is calculated, and the error curve is determined based on the position error mean value.

[0024] Furthermore, calibrating the rotor position based on the error curve includes:

[0025] The current true position of the target point is determined, a current position error corresponding to the current true position is determined based on the error curve, and the rotor position is corrected based on a linear interpolation method and the current position error.

[0026] Furthermore, the correcting the rotor position based on linear interpolation and the current position error includes:

[0027] The current true position and the current position error are summed and calculated to obtain a target rotor position of the rotor, and the torque signal of the motor is adjusted based on the target rotor position so that the rotor position remains consistent with the target rotor position.

[0028] Furthermore, before determining the theoretical position of the target point on the rotor of the motor at the periodic time point for the target speed according to the preset target speed, the method further includes:

[0029] Power information of the motor is acquired, and whether the motor is in a no-load state is determined according to the power information; when it is determined that the motor is in a no-load state, the rotor position is calibrated.

[0030] According to another aspect of the present invention, the present invention further provides a rotor position calibration device for a permanent magnet synchronous motor, the device comprising:

[0031] a theoretical position determination module, configured to determine, based on a preset target speed, a theoretical position of a target point on the rotor of the motor at a periodic time point for the target speed;

[0032] a driving module and a real position monitoring module, wherein the driving module is configured to determine a target driving force according to the target speed and apply the target driving force to the rotor to rotate the rotor, and the real position monitoring module monitors the real position of the target point at the periodic time points in real time;

[0033] a position error determination module, configured to determine position errors at multiple time points within a preset measurement period based on the theoretical position and the actual position;

[0034] The rotor position calibration module is configured to determine an error curve based on the position error and calibrate the rotor position based on the error curve.

[0035] According to another aspect of the present invention, the present invention further provides a storage medium, wherein a plurality of instructions are stored in the storage medium, and the instructions are suitable for being loaded by a processor to execute any rotor position calibration method as described above.

[0036] Through one or more of the above embodiments of the present invention, at least the following technical effects can be achieved:

[0037] In the technical solution disclosed in the present invention, the theoretical position and the actual position of the rotor are determined, and then the position errors at multiple time points are calculated. Then, the error curve is determined based on the position error, and finally, the rotor position is calibrated based on the error curve. Through the technical solution of the present invention, the nonlinear rotor position can be corrected, and an accurate rotor position signal can be obtained in real time, avoiding the problem of motor torque fluctuation. In addition, the technical solution of this solution does not need to rely on workbench resources and has no requirements for the rotor correction scenario. Even when the permanent magnet synchronous motor is installed on the application equipment, the rotor position correction can be performed. Therefore, through the technical solution of the present invention, an accurate and real-time rotor position signal can be obtained, and it can be widely used in permanent magnet synchronous motors in various scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] The technical solutions and other beneficial effects of the present invention will be made apparent by describing in detail the specific embodiments of the present invention in conjunction with the accompanying drawings.

[0039] FIG1 is a flowchart of a method for calibrating a rotor position according to an embodiment of the present invention;

[0040] FIG2 is a schematic diagram showing a nonlinear rotor position in the present invention;

[0041] FIG3 is a schematic diagram of the rotor position change in the present invention;

[0042] FIG4 is a schematic diagram of another nonlinear rotor position according to the present invention;

[0043] FIG5 is a schematic diagram of position error within one rotation cycle in the present invention;

[0044] FIG6 is a schematic structural diagram of a rotor position calibration device provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0045] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without making any creative efforts shall fall within the scope of protection of the present invention.

[0046] According to one aspect of the present invention, a rotor position calibration method is provided. FIG1 is a flowchart of the steps of the rotor position calibration method provided by an embodiment of the present invention. The rotor position calibration method includes:

[0047] Step 101: determining a theoretical position of a target point on the rotor of the motor at a periodic time point according to a preset target speed;

[0048] Step 102: determining a target driving force according to the target speed and applying the target driving force to the rotor to rotate the rotor, and monitoring the actual position of the target point at the periodic time point in real time;

[0049] Step 103: determining position errors at multiple time points within a preset measurement period according to the theoretical position and the actual position;

[0050] Step 104: Determine an error curve based on the position error, and calibrate the rotor position based on the error curve.

[0051] The permanent magnet synchronous motor is an AC motor, which is mainly composed of components such as a stator, a rotor and an end cover. Among them, the rotor is a permanent magnet, and the rotor speed is the same as the speed of the stator rotating magnetic field. When the motor components are improperly installed or age with use, the rotor position signal will show nonlinearity, which will cause the motor torque to fluctuate, seriously affecting the normal use of the product. Figure 2 is a schematic diagram of the nonlinear rotor position in the present invention. Under normal circumstances, the real position of the rotor should be consistent with the theoretical position. However, improper installation or aging of the motor will cause nonlinearity. When the motor is running, the position of the rotor is the real position in Figure 2, and a position deviation occurs between the theoretical position and the real position. This solution can correct the position deviation of the rotor and does not need to rely on a workbench. The necessary condition is to keep the motor in a stable state and achieve speed self-balancing. The prerequisite for eliminating the rotor position error is: the motor is rotated to the target speed through the rotor theoretical position. Only when the motor reaches a stable target speed can the error be eliminated.

[0052] The following example illustrates how to keep the motor in a stable state. FIG3 is a schematic diagram of the rotor position change in the present invention, assuming that the motor resistance is 1 Nm and the driving force is 5 Nm. When the driving force of the motor is greater than the motor resistance, the speed of the rotor is accelerated. As shown in FIG3 , assuming that the given virtual speed is 20 rpm, a theoretical position signal θ2 of a certain frequency is generated, and the real position θ1 of the rotor gradually approaches the theoretical position (not exceeding 20 rpm) during the acceleration process. When the actual speed exceeds the set 20 rpm, as shown in FIG3 , the real position θ1 will exceed the theoretical position θ2. Among them, the angle θe between the real position θ1 and the theoretical position θ2 can be regarded as the power angle, and the motor torque, motor current and power angle satisfy the following relationship:

[0053] Tq=lq*COS(θe),

[0054] Where Tq is the motor torque, lq is the motor current, and θe is the power angle.

[0055] The relationship between motor torque, motor current, and power angle shows that torque depends on the actual motor current. The accuracy of the motor current is related to the accuracy of the rotor position. The more accurate the rotor position, the closer the actual motor current is to the target current value. Therefore, the theoretical rotor position θ2 is used as a reference. When the rotor position deviates from the theoretical position θ2, the accuracy of the motor current and rotor position decreases. Position accuracy can be expressed as COS(θe).

[0056] In the rotor position change process shown in Figure 3, when the actual position θ1 exceeds the theoretical position θ2, as the power angle θe increases, the motor torque Tq decreases. Correspondingly, the rotor speed slows, which in turn slows the actual position θ1. As the actual position θ1 gradually approaches the theoretical position θ2, the power angle θe decreases again. The greater the deviation in rotor position accuracy, the smaller COS(θe), and the smaller the torque generated. This smaller torque reduces the actual rotor position speed.

[0057] When the power angle θe decreases, the motor torque Tq increases again, and the motor rotor accelerates. The acceleration will cause the actual position θ1 to gradually move away from the theoretical position θ2. Correspondingly, the power angle θe will increase.

[0058] By repeatedly adjusting the above two processes, the deviation between the actual position θ1 and the theoretical position θ2 is reduced until the power angle θe is zero.

[0059] In the present invention, the rotor position calibration needs to be performed when the motor is in a no-load state, for example, calibration-related data is pre-determined when the motor is in a no-load state before leaving the factory, or calibration-related data is pre-determined after creating a no-load-like working condition when the motor is running.

[0060] The motor rotor's position error is primarily caused by the placement of the position sensor and magnet. Therefore, after the device is packaged, the position-induced error value varies minimally. Varying rotor speeds only cause variations in the rotor's operating cycle, without significantly changing the error value. Once the rotor calibration data is determined, it can be saved and used to calibrate the rotor within a preset timeframe.

[0061] The above steps 101 to 104 are described in detail below.

[0062] In step 101 , a theoretical position of a target point on the rotor of the motor at a periodic time point for the target speed is determined according to a preset target speed.

[0063] For example, the rotor of a permanent magnet synchronous motor is a permanent magnet. During motor operation, the rotor speed is the same as the speed of the stator's rotating magnetic field. Before setting the motor's operating parameters, the target rotor speed is preset in advance based on information such as the parameters of the required alternating current. The motor current is adjusted based on the target speed, and the motor torque is then adjusted to achieve rotor rotation. There is a preset initial point on the rotor and stator, which is the initial position of the target point. After the rotor rotates stably, the time when the target point passes the initial position is recorded, and the rotor rotation cycle begins. Within each cycle, the theoretical position of the target point is calculated based on the periodic time point and the target speed.

[0064] In step 102 , a target driving force is determined according to the target rotational speed and applied to the rotor to rotate the rotor, and the actual position of the target point at the periodic time point is monitored in real time.

[0065] For example, in a permanent magnet synchronous motor, after the motor current and rotor position are determined, the duty cycle of the motor can be determined. The duty cycle motor forms an internal feedback, and the motor current is adjusted based on the duty cycle, that is, the target driving force of the motor is adjusted, thereby changing the torque of the motor to achieve the rotation of the rotor according to the target speed. Among them, a position sensor for real-time monitoring of the rotor position information is provided on the motor. The position sensor can be of various types to determine the current position information of the rotor in real time. In the present invention, before the position sensor obtains the position signal, a plurality of periodic time points are preset in advance based on the cycle time and accuracy standards, and one cycle is divided into a preset number of time periods. The rotor position information is collected at the preset time point of each time period.

[0066] In step 103, position errors at multiple time points within a preset measurement period are determined according to the theoretical position and the actual position.

[0067] For example, in the present invention, a measurement cycle is preset in advance, comprising a plurality of rotor rotation cycles. After the motor is started and the rotor speed stabilizes, position errors are calculated at multiple time points within each cycle based on the calculated theoretical position and the real position monitored in real time during the preset measurement cycle.

[0068] Among them, in the rotor position change schematic diagram in Figure 2, the periodic position error between the real position and the theoretical position is ignored. Figure 4 is another schematic diagram of the rotor position in the present invention that is nonlinear. To be precise, the schematic diagram of the real position and the theoretical position is shown in Figure 4. The real actual position error is the accumulation of the periodic position error and the position error in Figure 2. In practical applications, the periodic position error in Figure 4 can be easily eliminated. Therefore, the rotor position calibration method of this scheme is based on the elimination of the periodic position error. Therefore, in this scheme, the position error defaults to the error between the real position and the theoretical position at the same time point shown in Figure 2. Figure 5 is a schematic diagram of the position error in the present invention. As shown in Figure 5, within one rotor rotation cycle, there is a deviation between the real position and the theoretical position during the rotor position change process. In the example shown in Figure 5, one rotor rotation cycle is divided into 15 parts, corresponding to 14 position errors at 14 time points.

[0069] In step 104 , an error curve is determined based on the position error, and the rotor position is calibrated based on the error curve.

[0070] For example, after determining multiple position errors, data processing is performed on the multiple position errors to fit an error curve. During the operation of the motor, the actual position of the motor rotor is obtained in real time, and the rotor position is calibrated according to the error curve to achieve accurate and stable operation of the permanent magnet synchronous motor.

[0071] Furthermore, determining the theoretical position of a target point on the rotor of the motor at a periodic time point for the target speed according to a preset target speed includes:

[0072] The theoretical rotation angle of the rotor is obtained according to the operating time of the target point and the target rotation speed, and the theoretical position is obtained according to the theoretical rotation angle and the initial position of the rotor.

[0073] For example, after the permanent magnet synchronous motor's rotor has stabilized, the time at which the target point is at its initial position is determined, and the rotor's operating time is calculated in real time based on the current time and the initial time. Then, based on the operating time and the target speed, the theoretical rotation angle of the rotor at the current time is determined. The initial position of the rotor is obtained, and the angle corresponding to the initial position is added to the theoretical rotation angle. The theoretical rotation angle is then converted to a central angle to obtain the theoretical position.

[0074] Furthermore, determining the target driving force according to the target speed includes:

[0075] The target driving force is determined based on a field oriented control method and the theoretical position corresponding to the target speed.

[0076] Furthermore, the determining the target driving force based on the magnetic field oriented control method and the theoretical position corresponding to the target speed includes:

[0077] A current motor current of the motor is acquired, a duty cycle of the motor is determined according to the motor current and the theoretical position, and the target driving force is determined based on the duty cycle.

[0078] For example, the duty cycle of the motor is determined by the Field Oriented Control (FOC) method and the theoretical position, and the motor current is adjusted according to the duty cycle, thereby adjusting the torque of the motor so that the motor runs at a specified speed. The duty cycle refers to the ratio of the power-on time of the pulse signal to the power-on period. In an ideal sequence of pulse cycles (such as a square wave), the ratio of the duration of the positive pulse to the total pulse period. The duty cycle refers to the ratio of the time occupied by the high level within one cycle. The duty cycle of the square wave is 50%, and the duty cycle is 0.5, which means that the positive level occupies 0.5 cycles.

[0079] Field-oriented control (FOC), also known as vector control, uses coordinate transformation to convert the control of three-phase AC power into the control of the q-axis current (which generates torque) and the d-axis current (which generates the magnetic field), achieving independent control of torque and excitation. Representing the magnetic field as a space vector, it is known that maximum torque is generated when the stator magnetic field is perpendicular to the rotor magnetic field. Therefore, maintaining this perpendicularity ensures optimal motor performance.

[0080] Furthermore, the real-time monitoring of the actual position of the target point at the periodic time point includes:

[0081] The actual position of the target point at the periodic time point is monitored by a magnetoelectric position sensor.

[0082] For example, a sensor for measuring the rotor position is provided on the permanent magnet synchronous motor. Specifically, the actual position of the target point at periodic time points can be monitored using a magnetoelectric position sensor. Among them, the magnetoelectric sensor is also called an electric or inductive sensor and is only suitable for dynamic measurement. The magnetoelectric sensor uses the principle of electromagnetic induction to convert the input motion speed into an induced potential output in the coil. It directly converts the mechanical energy of the object being measured into an electrical signal output and does not require an external power supply to operate. It is a typical passive sensor. The magnetoelectric position sensor has a large output power, a simple circuit, and stable zero position and performance, so it is widely used. It should be noted here that in actual applications, there is no restriction on the type of sensor. Other position sensors, such as Hall position sensors, inductive position sensors, etc., can also be used. The optimal sensor can be selected according to the actual application.

[0083] Furthermore, determining the position errors at multiple time points within a preset measurement period according to the theoretical position and the actual position includes:

[0084] Determining the number of rotation periods of the rotor within the preset measurement period and a sampling sequence for sampling the position error within one rotation period, wherein the sampling sequence corresponds to the periodic time points in a one-to-one correspondence;

[0085] For each rotation period within the preset measurement period, position errors at multiple time points within the rotation period are determined based on the sampling sequence, the theoretical position, and the actual position.

[0086] Exemplarily, the preset measurement period includes a plurality of rotation periods. For example, if the preset measurement period is 10 rotor rotation periods, rotor position data within the 10 periods is collected to calculate the position error. To improve the accuracy of the rotor position calibration, the rotor rotation period may be increased, such as to 20 or 50 rotor rotation periods, to achieve more accurate position calibration.

[0087] After determining the number of rotation cycles of the rotor within a preset measurement period, sampling is performed at multiple preset time points for each rotation period to calculate the position error of the rotor. FIG5 is a schematic diagram of the position error in the present invention. As shown in FIG5 , within one rotation period, there are 14 sampling sequences, corresponding to 14 period time points respectively.

[0088] Assuming that the preset measurement period includes 10 rotor rotation periods and there are 14 position errors in each rotation period, there are 140 position errors in the preset measurement period.

[0089] Furthermore, determining an error curve based on the position error includes:

[0090] A position error mean value of each sampling sequence in the sampling sequences is calculated, and the error curve is determined based on the position error mean value.

[0091] For each sampling sequence in the sampling sequence, a target position error corresponding to the sampling sequence in each rotation period within the preset measurement period is obtained to obtain multiple target position errors corresponding to the sampling sequence. An average operation is performed on the multiple target position errors to obtain a position error mean corresponding to the sampling sequence.

[0092] Specifically, to improve the accuracy of error calibration, after obtaining all position errors within a preset measurement period, for each sampling sequence, the target position errors within all rotation periods corresponding to the sampling sequence are obtained. The position errors corresponding to each sampling sequence are data processed, and the average of the multiple target position errors is calculated to obtain multiple position error averages. For example, if the corresponding preset measurement period includes 10 rotor rotation periods, and there are 14 position errors within each rotation period, there are 140 position errors within the preset measurement period. For each of the 14 sampling sequences, the average of the 10 position errors corresponding to each sequence is calculated to obtain 14 position error averages.

[0093] After determining the mean values ​​of all position errors, data processing is performed on the mean values ​​of position errors, and an error curve is fitted based on a mathematical optimization algorithm.

[0094] Furthermore, calibrating the rotor position based on the error curve includes:

[0095] The current true position of the target point is determined, a current position error corresponding to the current true position is determined based on the error curve, and the rotor position is corrected based on a linear interpolation method and the current position error.

[0096] Illustratively, after determining the error curve, the rotor position is corrected using the error curve. Alternatively, the rotor position can be corrected using position errors at multiple preset time points. Alternatively, the multiple position error means can be directly processed using a linear interpolation method, and the rotor position can be compensated using the position error means. Alternatively, at the current time of rotor operation, the current true position is obtained, and the position error corresponding to the current true position is determined on the error curve. The rotor position is then corrected using linear interpolation and the position error.

[0097] Linear interpolation is an interpolation method where the interpolation function is a linear polynomial, and the interpolation error at the interpolation nodes is zero. Compared to other interpolation methods, such as parabolic interpolation, linear interpolation is simpler and more convenient.

[0098] Furthermore, the correcting the rotor position based on linear interpolation and the current position error includes:

[0099] The current true position and the current position error are summed and calculated to obtain a target rotor position of the rotor, and the torque signal of the motor is adjusted based on the target rotor position so that the rotor position remains consistent with the target rotor position.

[0100] For example, when controlling the speed of a motor, two adjustment signals are primarily input: one adjustment signal is related to the desired rotor position, and the other is related to the torque. In the present invention, to ensure that the rotor position is consistent with the target rotor position, the target rotor position for the rotor in its current state is first calculated. The target rotor position is then used to adjust the motor's torque signal. The motor then adjusts the rotor speed based on the torque signal, completing the rotor position correction.

[0101] Furthermore, before determining the theoretical position of the target point on the rotor of the motor at the periodic time point for the target speed according to the preset target speed, the method further includes:

[0102] Power information of the motor is acquired, and whether the motor is in a no-load state is determined according to the power information; when it is determined that the motor is in a no-load state, the rotor position is calibrated.

[0103] For example, to ensure the accuracy of the measured position error, it is necessary to ensure that the motor is in a no-load state when the position error is obtained. For example, calibration data can be pre-determined in the no-load state before the motor leaves the factory, or calibration data can be pre-determined after creating a no-load-like operating condition while the motor is running.

[0104] Through one or more of the above embodiments of the present invention, at least the following technical effects can be achieved:

[0105] In the technical solution disclosed in the present invention, the theoretical position and the actual position of the rotor are determined, and then the position errors at multiple time points are calculated. Then, the error curve is determined based on the position error, and finally, the rotor position is calibrated based on the error curve. Through the technical solution of the present invention, the nonlinear rotor position can be corrected, and an accurate rotor position signal can be obtained in real time, avoiding the problem of motor torque fluctuation. In addition, the technical solution of this solution does not need to rely on workbench resources and has no requirements for the rotor correction scenario. Even when the permanent magnet synchronous motor is installed on the application equipment, the rotor position correction can be performed. Therefore, through the technical solution of the present invention, an accurate and real-time rotor position signal can be obtained, and it can be widely used in permanent magnet synchronous motors in various scenarios.

[0106] Based on the same inventive concept as the rotor position calibration method of an embodiment of the present invention, an embodiment of the present invention further provides a rotor position calibration device for a permanent magnet synchronous motor. Referring to FIG6 , the device includes:

[0107] The theoretical position determination module 201 is used to determine the theoretical position of a target point on the rotor of the motor at a periodic time point according to a preset target speed;

[0108] a driving module 202 and a real position monitoring module 203, wherein the driving module is configured to determine a target driving force according to the target speed and apply the target driving force to the rotor to rotate the rotor, and the real position monitoring module monitors the real position of the target point at the periodic time points in real time;

[0109] a position error determination module 204, configured to determine position errors at multiple time points within a preset measurement period based on the theoretical position and the actual position;

[0110] The rotor position calibration module 205 is configured to determine an error curve based on the position error, and calibrate the rotor position based on the error curve.

[0111] Furthermore, the theoretical position determination module 201 is further configured to:

[0112] The theoretical rotation angle of the rotor is obtained according to the operating time of the target point and the target rotation speed, and the theoretical position is obtained according to the theoretical rotation angle and the initial position of the rotor.

[0113] Furthermore, the driving module 202 is further configured to:

[0114] The target driving force is determined based on a field oriented control method and the theoretical position corresponding to the target speed.

[0115] Furthermore, the driving module 202 is further configured to:

[0116] A current motor current of the motor is acquired, a duty cycle of the motor is determined according to the motor current and the theoretical position, and the target driving force is determined based on the duty cycle.

[0117] Furthermore, the real location monitoring module 203 is further configured to:

[0118] The actual position of the target point at the periodic time point is monitored by a magnetoelectric position sensor.

[0119] Furthermore, the position error determination module 204 is further configured to:

[0120] Determining the number of rotation periods of the rotor within the preset measurement period and a sampling sequence for sampling the position error within one rotation period, wherein the sampling sequence corresponds to the periodic time points in a one-to-one correspondence;

[0121] For each rotation period within the preset measurement period, position errors at multiple time points within the rotation period are determined based on the sampling sequence, the theoretical position, and the actual position.

[0122] Furthermore, the rotor position calibration module 205 is further configured to:

[0123] A position error mean value of each sampling sequence in the sampling sequences is calculated, and the error curve is determined based on the position error mean value.

[0124] Furthermore, the rotor position calibration module 205 is further configured to:

[0125] For each sampling sequence in the sampling sequences, obtaining a target position error corresponding to the sampling sequence in each rotation period within the preset measurement period to obtain a plurality of target position errors corresponding to the sampling sequence;

[0126] An averaging operation is performed on the multiple target position errors to obtain a position error mean corresponding to the sampling sequence.

[0127] Furthermore, the rotor position calibration module 205 is further configured to:

[0128] The current true position of the target point is determined, a current position error corresponding to the current true position is determined based on the error curve, and the rotor position is corrected based on a linear interpolation method and the current position error.

[0129] Among them, other aspects and implementation details of the rotor position calibration device are the same as or similar to the rotor position calibration method described above, and are not repeated here.

[0130] According to another aspect of the present invention, the present invention further provides a storage medium, wherein a plurality of instructions are stored in the storage medium, and the instructions are suitable for being loaded by a processor to execute any rotor position calibration method as described above.

[0131] In summary, although the present invention has been disclosed above with reference to preferred embodiments, the above preferred embodiments are not intended to limit the present invention. A person skilled in the art may make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be based on the scope defined in the claims.

Claims

1. A rotor position calibration method for a permanent magnet synchronous motor, characterized in that: The method comprises: Determining, according to a preset target speed, a theoretical position of a target point on the rotor of the motor at a periodic time point for the target speed; determining a target driving force according to the target rotational speed, applying the target driving force to the rotor to rotate the rotor, and monitoring in real time the actual position of the target point at the periodic time point; determining position errors at multiple time points within a preset measurement period according to the theoretical position and the actual position; An error curve is determined based on the position error, and the rotor position is calibrated based on the error curve.

2. The method according to claim 1, wherein Determining the theoretical position of a target point on the rotor of the motor at a periodic time point according to a preset target speed includes: The theoretical rotation angle of the rotor is obtained according to the operating time of the target point and the target rotation speed, and the theoretical position is obtained according to the theoretical rotation angle and the initial position of the rotor.

3. The method according to claim 1, wherein Determining the target driving force according to the target speed includes: The target driving force is determined based on a field oriented control method and the theoretical position corresponding to the target speed.

4. The method according to claim 3, wherein The determining of the target driving force based on the magnetic field oriented control method and the theoretical position corresponding to the target speed includes: A current motor current of the motor is acquired, a duty cycle of the motor is determined according to the motor current and the theoretical position, and the target driving force is determined based on the duty cycle.

5. The method according to claim 1, wherein The real-time monitoring of the actual position of the target point at the periodic time point includes: The actual position of the target point at the periodic time point is monitored by a magnetoelectric position sensor.

6. The method according to claim 1, wherein Determining the position errors at multiple time points within a preset measurement period according to the theoretical position and the actual position includes: Determining the number of rotation periods of the rotor within the preset measurement period and a sampling sequence for sampling the position error within one rotation period, wherein the sampling sequence corresponds to the periodic time points in a one-to-one correspondence; For each rotation period within the preset measurement period, position errors at multiple time points within the rotation period are determined based on the sampling sequence, the theoretical position, and the actual position.

7. The method according to claim 6, wherein Determining an error curve based on the position error includes: A position error mean of each sampling sequence in the sampling sequences is calculated, and the error curve is determined based on the position error mean.

8. The method according to claim 1, wherein The calibrating the rotor position based on the error curve includes: The current true position of the target point is determined, a current position error corresponding to the current true position is determined based on the error curve, and the rotor position is corrected based on a linear interpolation method and the current position error.

9. The method according to claim 8, wherein The correcting the rotor position based on the linear interpolation method and the current position error includes: The current true position and the current position error are summed and calculated to obtain a target rotor position of the rotor, and the torque signal of the motor is adjusted based on the target rotor position so that the rotor position remains consistent with the target rotor position.

10. The method according to claim 1, wherein Before determining the theoretical position of the target point on the rotor of the motor at the periodic time points according to the preset target speed, the method further includes: Power information of the motor is acquired, whether the motor is in a no-load state is determined according to the power information, and the rotor position is calibrated when it is determined that the motor is in a no-load state.

11. A motor rotor position calibration device for a permanent magnet synchronous motor, characterized in that: The device comprises: a theoretical position determination module, configured to determine, based on a preset target speed, a theoretical position of a target point on the rotor of the motor at a periodic time point for the target speed; The driving module is configured to determine a target driving force according to the target rotational speed and apply the target driving force to the rotor to rotate the rotor; The real position monitoring module is used to monitor the real position of the target point at the periodic time point in real time; a position error determination module, configured to determine position errors at multiple time points within a preset measurement period based on the theoretical position and the actual position; The rotor position calibration module is configured to determine an error curve based on the position error and calibrate the rotor position based on the error curve.

12. A storage medium, characterized in that: The storage medium stores a plurality of instructions, and the instructions are suitable for being loaded by a processor to execute the method according to any one of claims 1 to 10.

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