Motor zero calibration method and device, storage medium and motor

Abstract

The invention discloses a method and a device for zero calibration of a motor, a storage medium and the motor. The method comprises the following steps: determining an initial zero angle of the motor; inputting current to the motor under the current carrier frequency to drive the motor to rotate forwards; after the rotating speed of the motor reaches the target rotating speed, the speed of the motor is freely reduced, and the PI controller determines a first zero angle enabling the d-axis voltage of the motor to be zero by taking the initial zero angle as a reference; and then the motor is driven to rotate reversely, and a second zero angle enabling the d-axis voltage of the motor to be zero is determined. And determining a third zero angle corresponding to the current carrier frequency according to the first zero angle and the second zero angle. And under different carrier frequencies, the PI controller respectively and repeatedly executes calibration operation by taking the third zero angle as a reference so as to obtain each target zero angle corresponding to each different carrier frequency. According to the scheme, the zero angles under different carrier frequencies are calibrated based on the calibrated zero angle, the calibration result is more accurate, and the efficiency is higher.

Description

Technical Field

[0001] The present application relates to the technical field of motor zero-position calibration, and in particular to a method, device, storage medium and motor for motor zero-position calibration. Background Art

[0002] In the process of implementing the vector control of the drive motor of the new energy vehicle, the synchronous coordinate system rotation angle is a crucial variable, and the synchronous coordinate system rotation angle is calculated with reference to the motor stator A phase winding, so it is necessary to first determine the position of the motor stator A phase winding (referred to as the motor zero position). In the prior art, the following zero position calibration methods are mainly involved, one is the manual adjustment of the zero position method, by manually adjusting the position of the rotary transformer, so that the phase voltage is consistent with the voltage direction of the rotary transformer, this method has very low accuracy and is greatly affected by human errors. One is to install the motor on the traction motor for zero position calibration, this method has a complex calibration process and high hardware requirements. Another is to control the motor's rotor to stop at the motor zero position by applying current, and then read the zero position angle measured by the rotary transformer. This method is affected by the mechanical friction resistance of the motor, resulting in errors in the calibration of the zero position angle. Summary of the invention

[0003] The purpose of the embodiments of the present application is to provide a method, device, storage medium and motor for motor zero position calibration, so as to solve the error in the calibration of zero position angle in the prior art.

[0004] In order to achieve the above-mentioned object, the first aspect of the present application provides a method for motor zero position calibration, the method comprising:

[0005] Step S1: Determine the initial zero angle of the motor;

[0006] Step S2: Under the current carrier frequency, input a first preset current to the motor to drive the motor to rotate along a first rotation direction;

[0007] Step S3: When the speed of the motor reaches the target speed, the current of the motor is disconnected to allow the motor to decelerate freely;

[0008] Step S4: During the free speed reduction of the motor, the PI controller uses the initial zero angle as a reference to determine a first zero angle that makes the d-axis voltage of the motor zero;

[0009] Step S5: inputting a second preset current into the motor to drive the motor to rotate along a second rotation direction;

[0010] Step S6: When the speed of the motor reaches the target speed, the current of the motor is disconnected to allow the motor to decelerate freely;

[0011] Step S7: During the free speed reduction of the motor, the PI controller uses the initial zero angle as a reference to determine a second zero angle that makes the d-axis voltage of the motor zero;

[0012] Step S8: determining a third null angle corresponding to the current carrier frequency according to the first null angle and the second null angle;

[0013] Step S9: Repeat steps S2 to S8 at different carrier frequencies to obtain target zero angles corresponding to different carrier frequencies, wherein the PI controller uses the third zero angle as a reference in the repeated steps S4 and S6.

[0014] In an embodiment of the present application, during the free deceleration of the motor, the PI controller uses the initial zero angle as a reference to determine the first zero angle that makes the d-axis voltage of the motor zero, including: setting the d-axis target voltage of the motor to zero; obtaining the d-axis feedback voltage of the motor; determining the voltage difference between the d-axis target voltage and the d-axis feedback voltage; adjusting the zero angle based on the initial zero angle so that the voltage difference is zero; and determining the zero angle when the voltage difference is zero as the first zero angle.

[0015] In an embodiment of the present application, during the free deceleration of the motor, the PI controller uses the initial zero angle as a reference to determine a second zero angle that makes the d-axis voltage of the motor zero, including: setting the d-axis target voltage of the motor to zero; obtaining the d-axis feedback voltage of the motor; determining the voltage difference between the d-axis target voltage and the d-axis feedback voltage; adjusting the zero angle based on the initial zero angle so that the voltage difference is zero; and determining the zero angle when the voltage difference is zero as the second zero angle.

[0016] In an embodiment of the present application, determining the initial zero angle of the motor includes: at the current carrier frequency, setting the voltage of the d-axis of the motor to a first preset voltage and setting the voltage of the q-axis of the motor to a second preset voltage to drive the motor to rotate in a first rotation direction, and then disconnecting the voltage of the motor to allow the motor to decelerate freely; when the motor decelerates to a stop, obtaining the current first initial zero angle of the motor; setting the voltage of the d-axis of the motor to a second preset voltage and setting the voltage of the q-axis of the motor to a first preset voltage to drive the motor to rotate in a second rotation direction, and then disconnecting the voltage of the motor to allow the motor to decelerate freely; when the motor decelerates to a stop, obtaining the current second initial zero angle of the motor; determining a first average of the first initial zero angle and the second initial zero angle as the initial zero angle of the motor.

[0017] In an embodiment of the present application, determining a third null angle corresponding to the current carrier frequency based on the first null angle and the second null angle includes: determining the average of the first null angle and the second null angle as the third null angle corresponding to the current carrier frequency.

[0018] In an embodiment of the present application, the method includes: obtaining a sampling interval for the zero angle and the angular velocity of the motor within the sampling interval; determining the actual time difference corresponding to the other carrier frequency based on the sampling interval and the current carrier frequency; and updating the target zero angle corresponding to the other carrier frequency based on the actual time difference and the angular velocity.

[0019] In an embodiment of the present application, the method also includes: when the motor is freely decelerating until the speed of the motor is zero, if the PI controller does not output the first zero angle, repeating steps S2 to S4 until the PI controller outputs the first zero angle; when the motor is freely decelerating until the speed of the motor is zero, if the PI controller does not output the second zero angle, repeating steps S5 to S8 until the PI controller outputs the second zero angle.

[0020] A second aspect of the present application provides a device for motor zero position calibration, comprising:

[0021] a memory configured to store instructions;

[0022] The processor is configured to call instructions from the memory and implement the above-mentioned method for motor zero position calibration when executing the instructions.

[0023] A third aspect of the present application provides a motor, comprising the above-mentioned device for motor zero position calibration.

[0024] A fourth aspect of the present application is a machine-readable storage medium having instructions stored thereon, the instructions being used to enable a machine to execute the above-mentioned method for motor zero position calibration.

[0025] Through the above technical scheme, based on the self-learning of the zero angle with the d-axis voltage being zero, the learned zero angle is more accurate and more robust. At the same time, self-learning is performed in both positive and negative directions, and the average value of the two zero angles obtained offsets the influence of different current directions, and the result is more accurate. In addition, the above scheme does not need to be tested on a dynamometer bench, is not restricted by the scene, and can be performed on flat ground, benches, etc. as long as the motor can rotate freely, and has strong versatility. Since the zero angle obtained by calibrating the motor of the current carrier frequency is already a more accurate angle relative to the initial zero angle, then for the calibration of the zero angle of different carrier frequencies, the calibration can be based on the previously calibrated zero angle as the initial zero angle, so that the zero angles calibrated by other different carrier frequencies are more accurate and more efficient.

[0026] Other features and advantages of the embodiments of the present application will be described in detail in the subsequent specific implementation section. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] The accompanying drawings are used to provide a further understanding of the embodiments of the present application and constitute a part of the specification. Together with the following specific implementations, they are used to explain the embodiments of the present application, but do not constitute a limitation on the embodiments of the present application. In the accompanying drawings:

[0028] Figure 1 A schematic diagram of a flow chart of a method for motor zero position calibration according to the first embodiment of the present application is shown;

[0029] Figure 2 A schematic diagram of a flow chart of a method for zero position calibration of a motor according to a second embodiment of the present application is shown;

[0030] Figure 3 A schematic diagram of a flow chart of a method for motor zero position calibration according to a third embodiment of the present application is shown;

[0031] Figure 4 A schematic diagram of a flow chart of a method for motor zero position calibration according to a fourth embodiment of the present application is shown;

[0032] Figure 5 A structural block diagram of a device for motor zero position calibration according to an embodiment of the present application is schematically shown;

[0033] Figure 6 The schematic diagram shows a structure of a computer device according to an embodiment of the present application. DETAILED DESCRIPTION

[0034] In order to make the purpose, technical scheme and advantages of the embodiments of the present application clearer, the technical scheme in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. It should be understood that the specific implementation methods described herein are only used to illustrate and explain the embodiments of the present application, and are not used to limit the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0035] It should be noted that if the embodiments of the present application involve directional indications (such as up, down, left, right, front, back...), the directional indications are only used to explain the relative position relationship, movement status, etc. between the components under a certain specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indication will also change accordingly.

[0036] In addition, if there are descriptions involving "first", "second", etc. in the embodiments of the present application, the descriptions of "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or suggesting their relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In addition, the technical solutions between the various embodiments can be combined with each other, but they must be based on the ability of ordinary technicians in the field to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be deemed that such combination of technical solutions does not exist and is not within the scope of protection required by this application.

[0037] Figure 1 The flowchart of a method for motor zero position calibration according to an embodiment of the present application is schematically shown. Figure 1 As shown, an embodiment of the present application provides a method for motor zero position calibration, which may include the following steps.

[0038] Step S1: Determine the initial zero angle of the motor;

[0039] Step S2: Under the current carrier frequency, input a first preset current to the motor to drive the motor to rotate along a first rotation direction;

[0040] Step S3: When the speed of the motor reaches the target speed, the current of the motor is disconnected to allow the motor to decelerate freely;

[0041] Step S4: During the free speed reduction of the motor, the PI controller uses the initial zero angle as a reference to determine a first zero angle that makes the d-axis voltage of the motor zero;

[0042] Step S5: inputting a second preset current into the motor to drive the motor to rotate along a second rotation direction;

[0043] Step S6: When the speed of the motor reaches the target speed, the current of the motor is disconnected to allow the motor to decelerate freely;

[0044] Step S7: During the free speed reduction of the motor, the PI controller uses the initial zero angle as a reference to determine a second zero angle that makes the d-axis voltage of the motor zero;

[0045] Step S8: determining a third null angle corresponding to the current carrier frequency according to the first null angle and the second null angle;

[0046] Step S9: Repeat steps S2 to S8 at different carrier frequencies to obtain target zero angles corresponding to different carrier frequencies, wherein the PI controller uses the third zero angle as a reference in the repeated steps S4 and S6.

[0047] At present, the control of permanent magnet synchronous motors can generally be achieved by FOC (Field-Oriented Control), or motor vector control. In FOC control, a PI controller (PI regulator) is often used to control the current loop of the permanent magnet synchronous motor.

[0048] It can be understood that the initial zero angle of the motor can be the zero angle obtained by performing a preliminary zero calibration on the motor. The initial zero angle is affected by friction resistance and inertia and will not be very accurate. Specifically, the initial zero angle can be calibrated by manually adjusting the zero position, the static voltage adjusting the zero position, and the rotational voltage deviation calibration method. The zero angle of the motor needs to be further calibrated to obtain a more accurate zero angle value. Specifically, the motor may refer to a permanent magnet synchronous motor. According to the principle of a permanent magnet synchronous motor, when the rotor magnetic field is an ideal sinusoidal distribution and the decoupling is complete, the main magnetic flux generated by the rotor permanent magnet causes the motion potential in the d-axis winding to be 0, and its back electromotive force will all fall on the q-axis, that is, U. d = 0. Therefore, the current closed-loop control of the motor can be performed based on the obtained preliminary zero-position angle of the motor.

[0049] It can be understood that the first preset current refers to the current value preset by the technician. The second preset current refers to the current value preset by the technician. The purpose of inputting the first preset current and the second preset current to the motor respectively is to drive the motor to rotate to the target speed. The first preset current can be the same as the second preset current. The first rotation direction and the second rotation direction are relative. When the first rotation direction is forward, the second rotation direction is reverse. When the first rotation direction is reverse, the second rotation direction is forward.

[0050] Specifically, at the current carrier frequency, by inputting current to the motor, the motor is driven to rotate, and the closed-loop control of the current is started. When the speed of the motor reaches the target speed, the current of the motor is disconnected so that the motor can decelerate freely. The target speed can refer to the rated speed of the motor. During the free deceleration of the motor, the PI controller uses the initial zero angle as a reference to determine the zero angle that makes the d-axis voltage of the motor zero. It can be understood that when the current of the motor is disconnected and the zero angle is accurately calibrated, the ideal d-axis voltage should be 0. However, since the initial zero angle may deviate from the accurate zero angle, when there is an error in the zero angle, the obtained d-axis voltage is not 0. Then, according to the principle of permanent magnet motor vector control, the PI controller can be based on the initial zero angle as a reference for high-speed self-learning, with the d-axis voltage being zero as the target value, and the corresponding zero angle is output when the d-axis voltage is zero. Wherein, the closed-loop control of the current includes driving the motor to rotate forward and reverse respectively, and obtaining the corresponding first zero angle and second zero angle. Then, taking into account the influence of the forward and reverse rotation of the motor, the final third zero angle corresponding to the current carrier frequency is obtained according to the first zero angle and the second zero angle.

[0051] Further, under other different carrier frequencies, a first preset current can be input into the motor to drive the motor to rotate in a first rotation direction; when the speed of the motor reaches the target speed, the current of the motor is disconnected to allow the motor to decelerate freely; during the free deceleration of the motor, the PI controller uses the third zero angle as a reference to determine a fourth zero angle that makes the d-axis voltage of the motor zero; a second preset current is input into the motor to drive the motor to rotate in a second rotation direction; when the speed of the motor reaches the target speed, the current of the motor is disconnected to allow the motor to decelerate freely; during the free deceleration of the motor, the PI controller uses the third zero angle as a reference to determine a fifth zero angle that makes the d-axis voltage of the motor zero; and a sixth zero angle corresponding to the other carrier frequency is determined based on the fourth zero angle and the fifth zero angle.

[0052] It is understandable that the calibration of the above-mentioned motor zero angle is affected by the carrier frequency conversion. The angle obtained by self-learning at different other carrier frequencies has different degrees of deviation. If other carrier frequencies are controlled with the same zero angle, it will not only cause torque deviation, but also reduce efficiency, and even easily cause overcurrent faults under certain extreme conditions. It is understandable that the third zero angle is a more accurate zero angle obtained through closed-loop control of current. Compared with directly using the initial zero angle to self-learn the zero angle, the current closed-loop control is performed based on the third zero angle to obtain U d=0 has a higher accuracy of the zero angle corresponding to it, and the time for adjustment and control is shorter. Therefore, for different carrier frequencies of the motor, the PI controller uses the third zero angle as a reference, and performs closed-loop control of the motor forward and motor reverse currents, respectively, so as to determine the zero angle that makes the d-axis voltage of the motor zero. Among them, for different carrier frequencies of the motor, the closed-loop control of the current includes driving the motor forward and reverse respectively, and obtaining the corresponding fourth zero angle and fifth zero angle. Then, considering the influence of the motor forward, reverse and carrier frequency, the final target zero angle corresponding to other carrier frequencies is obtained according to the fourth zero angle and the fifth zero angle. Then, after calibrating the zero angles of multiple carrier frequencies, they can be recorded in a table. In actual production activities, the table can be directly queried to obtain the motor zero angle under different carrier frequencies, which is simpler and more convenient.

[0053] Through the above technical solution, based on the self-learning of the zero angle with the d-axis voltage being zero, the learned zero angle is more accurate and more robust. At the same time, self-learning is performed in both positive and negative directions, and the average value of the two zero angles obtained offsets the influence of different current directions, and the result is more accurate. In addition, the above solution does not need to be tested on a dynamometer bench, is not restricted by the scene, and can be performed on flat ground, benches, etc. as long as the motor can rotate freely, and has strong versatility. Since the zero angle obtained by calibrating the motor of the current carrier frequency is already a more accurate angle relative to the initial zero angle, then for the calibration of the zero angle of different carrier frequencies, the calibration can be based on the previously calibrated zero angle as the initial zero angle, so that the zero angles calibrated by other different carrier frequencies are more accurate and the calibration efficiency is higher.

[0054] In an embodiment of the present application, during the free deceleration of the motor, the PI controller uses the initial zero angle as a reference to determine the first zero angle that makes the d-axis voltage of the motor zero, including: setting the d-axis target voltage of the motor to zero; obtaining the d-axis feedback voltage of the motor; determining the voltage difference between the d-axis target voltage and the d-axis feedback voltage; adjusting the zero angle based on the initial zero angle so that the voltage difference is zero; and determining the zero angle when the voltage difference is zero as the first zero angle.

[0055] In an embodiment of the present application, during the free deceleration of the motor, the PI controller uses the initial zero angle as a reference to determine a second zero angle that makes the d-axis voltage of the motor zero, including: setting the d-axis target voltage of the motor to zero; obtaining the d-axis feedback voltage of the motor; determining the voltage difference between the d-axis target voltage and the d-axis feedback voltage; adjusting the zero angle based on the initial zero angle so that the voltage difference is zero; and determining the zero angle when the voltage difference is zero as the second zero angle.

[0056] Specifically, in the process of adjustment, the motor vector control method is adopted. After obtaining the d-axis feedback voltage of the motor, the d-axis feedback voltage of the direct axis (d-axis) rotating with the rotor is projected to the a, b, and c three-phase coordinates of the stator through inverse park transformation, and the voltage values ​​corresponding to the converted a, b, and c three-phase coordinates are obtained. Further, SVM (space vector modulation) is used to generate a pulse width modulation (PWM) signal based on the voltage value of the a, b, and c three-phase coordinates to control the switch of the inverter, thereby generating the required modulation voltage to drive the motor to the required speed or torque. Further, during the rotation of the motor, the current value of the a, b, and c three-phase coordinates of the motor is collected at this time, and the current value of the a, b, and c three-phase coordinates of the motor is converted into the current value of the α and β two-phases. After this conversion, the effective value of the current or voltage remains unchanged before and after the conversion, but the phase and amplitude will change. Further, the current values ​​of the α and β two-phases are park transformed to obtain the d-axis feedback voltage. Then, after obtaining the d-axis feedback voltage to determine U d After the difference between the target value and the feedback value is obtained, the PI controller repeats the above steps to adjust (accumulate) the zero angle until the voltage difference is zero, and the zero angle at this time is recorded as the first zero angle. Similarly, the second zero angle can also be determined by determining the first zero angle. In the process of determining the first zero angle and the second zero angle, the principle of motor vector control is adopted, and the zero angle is adjusted by the PI regulator, so that an accurate zero angle can be obtained.

[0057] In an embodiment of the present application, determining the initial zero angle of the motor includes: at the current carrier frequency, setting the voltage of the d-axis of the motor to a first preset voltage and setting the voltage of the q-axis of the motor to a second preset voltage to drive the motor to rotate in a first rotation direction, and then disconnecting the voltage of the motor to allow the motor to decelerate freely; when the motor decelerates to a stop, obtaining the current first initial zero angle of the motor; setting the voltage of the d-axis of the motor to a second preset voltage and setting the voltage of the q-axis of the motor to a first preset voltage to drive the motor to rotate in a second rotation direction, and then disconnecting the voltage of the motor to allow the motor to decelerate freely; when the motor decelerates to a stop, obtaining the current second initial zero angle of the motor; determining a first average of the first initial zero angle and the second initial zero angle as the initial zero angle of the motor.

[0058] It can be understood that the initial zero angle of the motor can be calibrated by manually adjusting the zero position, static voltage adjusting the zero position, and rotating voltage deviation calibration. Among them, the manual adjustment zero position method is affected by human adjustment and has a large error. The rotating voltage deviation calibration method is not suitable for other no-load occasions, and is greatly affected by the system resistance and has poor versatility. Preferably, the static voltage adjustment zero position method is adopted. It can be understood that the first preset voltage and the second preset voltage are voltage values ​​pre-set by the technician, respectively. Specifically, by giving the voltage instructions corresponding to the d-axis voltage and the q-axis voltage of the motor phase, the motor rotor rotates an angle under the influence of the electromagnetic torque, and the rotary transformer follows the rotation, and this angle is recorded as the zero angle of the rotary transformer. Among them, the calibration of the initial zero angle includes driving the motor forward and reverse respectively, and obtaining the corresponding first initial zero angle and second initial zero angle. Then, the influence of the forward and reverse rotation of the motor is integrated, and the final initial zero angle corresponding to the current carrier frequency is obtained according to the first initial zero angle and the second initial zero angle, which offsets the influence of different current directions, making the result more accurate.

[0059] refer to Figure 2 In one embodiment, after the host computer sends a start learning instruction, the motor is controlled to enter the voltage control mode of the static voltage adjustment zero position method, and U d =x,U q = 0, the motor is driven to rotate in the forward direction, and the first initial zero angle is obtained. Then let U d =0,U q = x, drive the motor to rotate in the opposite direction to obtain the second initial zero angle. The average of the first initial zero angle and the second initial zero angle is used as the initial zero angle to enter the high-speed self-learning of the current closed-loop control. After successful learning, the final zero angle value, i.e., the third zero angle, is returned.

[0060] In an embodiment of the present application, determining a third null angle corresponding to the current carrier frequency according to the first null angle and the second null angle includes: determining the mean of the first null angle and the second null angle as the third null angle corresponding to the current carrier frequency. The mean of the first null angle and the second null angle combines the influence of the forward and reverse rotation of the motor, offsets the influence of different current directions, reduces the error caused by the hardware factors and operation factors of the motor itself, and makes the result more accurate.

[0061] In an embodiment of the present application, the method also includes: when the motor is freely decelerating until the speed of the motor is zero, if the PI controller does not output the first zero angle, repeating steps S2 to S4 until the PI controller outputs the first zero angle; when the motor is freely decelerating until the speed of the motor is zero, if the PI controller does not output the second zero angle, repeating steps S5 to S8 until the PI controller outputs the second zero angle.

[0062] refer to Figure 3 In one embodiment, after the host computer sends a start learning instruction, after determining the initial zero angle of the motor, a first preset current I is input to the motor at the current carrier frequency (for example, 8000 Hz). s =y, to drive the motor to rotate in the forward direction. When the motor speed speed reaches the rated speed, the current of the motor is disconnected to allow the motor to decelerate freely. After the motor decelerates freely to a speed speed < 0.8 times the rated speed, the PI controller uses the initial zero angle as a reference to determine the first zero angle θ1 that makes the d-axis voltage of the motor zero. If the motor decelerates freely to zero speed but the d-axis voltage has not yet reached zero, current is input to the motor again, and the above steps are repeated until the PI regulator obtains the first zero angle θ1 at which the d-axis voltage is zero. Furthermore, a second preset current I is input to the motor. s =y, to drive the motor to rotate in the opposite direction. When the motor speed speed reaches the rated speed, the current of the motor is disconnected to allow the motor to decelerate freely. After the motor decelerates freely to a speed speed < 0.8 times the rated speed, the PI controller uses the initial zero angle as a reference to determine the second zero angle θ2 that makes the d-axis voltage of the motor zero. If the motor decelerates freely to zero speed but the d-axis voltage has not yet reached zero, current is re-input into the motor and the above steps are repeated until the PI regulator obtains the second zero angle θ2 at which the d-axis voltage is zero. The third zero angle corresponding to the current carrier frequency is determined based on the first zero angle and the second zero angle.

[0063] In an embodiment of the present application, the method includes: obtaining a sampling interval for the zero angle and the angular velocity of the motor within the sampling interval; determining the actual time difference corresponding to other carrier frequencies based on the sampling interval and the current carrier frequency; and updating the target zero angle corresponding to other carrier frequencies based on the actual time difference and the angular velocity.

[0064] Considering that different electronic control systems have a time difference between the sampling and use of the zero angle when performing angle sampling and using the voltage inverse Park transform. The time difference will be different for different controller software strategies, for example, there is a 1.5-fold switching cycle. Therefore, when the voltage inverse Park transform is actually used in the program, the angle within the time difference is compensated according to the current carrier frequency. Then, it is necessary to further consider the influence of different carrier frequencies on the basis of considering the time difference between angle sampling and using the voltage inverse Park transform to obtain the actual time difference. Specifically, the actual time difference = time difference × (sampling interval × current operating carrier frequency / carrier frequency when measuring the sampling interval), then the angle of rotation of the motor within this actual time difference can be further calculated based on the angular velocity of the motor during this period, combined with the actual time difference, that is, the final target zero angle = target zero angle + actual time difference × angular velocity.

[0065] refer to Figure 4 In one embodiment, after the host computer sends a start learning instruction, the motor is controlled to enter the voltage control mode and perform self-learning of the static zero position. Specifically, let U d =x,U q = 0, the motor is driven to rotate in the forward direction, and the first initial zero angle is obtained. Then let U d =0,U q =x, the drive motor rotates in the opposite direction to obtain the second initial zero angle. After the self-learning of the static zero position, the average of the first initial zero angle and the second initial zero angle is used as the initial zero angle to enter the high-speed zero angle self-learning of the current closed-loop control for the fixed carrier frequency. After the learning is successful, the final zero angle value is returned. According to the average of the returned first zero angle and the second zero angle, the final third zero angle is obtained. Further, after the high-speed zero self-learning of the fixed carrier frequency, the high-speed zero angle self-learning of the current closed-loop control for different carrier frequencies is entered according to the third zero angle obtained as a reference. After the learning is successful, the final zero angle value is returned. According to the average of the returned fourth zero angle and the fifth zero angle, the target zero angle is obtained. Further, after the high-speed zero self-learning of the variable carrier frequency, the angle delay compensation is taken into account to obtain the final zero angle for different carrier frequencies.

[0066] Figure 1 FIG. 1 is a flow chart of a method for motor zero position calibration in one embodiment. It should be understood that although Figure 1 The steps in the flowchart are shown in sequence as indicated by the arrows, but these steps are not necessarily executed in the order indicated by the arrows. Unless otherwise specified in this document, there is no strict order restriction for the execution of these steps, and these steps can be executed in other orders. Moreover, Figure 1At least part of the steps may include multiple sub-steps or multiple stages. These sub-steps or stages are not necessarily executed at the same time, but can be executed at different times. The execution order of these sub-steps or stages is not necessarily sequential, but can be executed in turn or alternately with other steps or at least part of the sub-steps or stages of other steps.

[0067] Figure 5 The structure block diagram of a device for motor zero position calibration according to an embodiment of the present application is schematically shown. Figure 5 As shown, an embodiment of the present application provides a device for motor zero position calibration, which may include:

[0068] a memory configured to store instructions;

[0069] The processor is configured to call instructions from the memory and implement the above-mentioned method for motor zero position calibration when executing the instructions.

[0070] Specifically, in the embodiment of the present application, the processor may be configured to:

[0071] Step S1: Determine the initial zero angle of the motor;

[0072] Step S2: Under the current carrier frequency, input a first preset current to the motor to drive the motor to rotate along a first rotation direction;

[0073] Step S3: When the speed of the motor reaches the target speed, the current of the motor is disconnected to allow the motor to decelerate freely;

[0074] Step S4: During the free speed reduction of the motor, the PI controller uses the initial zero angle as a reference to determine a first zero angle that makes the d-axis voltage of the motor zero;

[0075] Step S5: inputting a second preset current into the motor to drive the motor to rotate along a second rotation direction;

[0076] Step S6: When the speed of the motor reaches the target speed, the current of the motor is disconnected to allow the motor to decelerate freely;

[0077] Step S7: During the free speed reduction of the motor, the PI controller uses the initial zero angle as a reference to determine a second zero angle that makes the d-axis voltage of the motor zero;

[0078] Step S8: determining a third null angle corresponding to the current carrier frequency according to the first null angle and the second null angle;

[0079] Step S9: Repeat steps S2 to S8 at different carrier frequencies to obtain target zero angles corresponding to different carrier frequencies, wherein the PI controller uses the third zero angle as a reference in the repeated steps S4 and S6.

[0080] In the embodiment of the present application, the processor may also be configured to:

[0081] The d-axis target voltage of the motor is set to zero; the d-axis feedback voltage of the motor is obtained; the voltage difference between the d-axis target voltage and the d-axis feedback voltage is determined; the zero angle is adjusted based on the initial zero angle so that the voltage difference is zero; and the zero angle when the voltage difference is zero is determined as the first zero angle.

[0082] In the embodiment of the present application, the processor may also be configured to:

[0083] The d-axis target voltage of the motor is set to zero; the d-axis feedback voltage of the motor is obtained; the voltage difference between the d-axis target voltage and the d-axis feedback voltage is determined; the zero angle is adjusted based on the initial zero angle so that the voltage difference is zero; and the zero angle when the voltage difference is zero is determined as a second zero angle.

[0084] In the embodiment of the present application, the processor may also be configured to:

[0085] Under the current carrier frequency, the d-axis voltage of the motor is set to a first preset voltage and the q-axis voltage of the motor is set to a second preset voltage to drive the motor to rotate in a first rotation direction, and then the voltage of the motor is disconnected to allow the motor to decelerate freely; when the motor decelerates to a stop, the current first initial zero angle of the motor is obtained; the d-axis voltage of the motor is set to a second preset voltage and the q-axis voltage of the motor is set to a first preset voltage to drive the motor to rotate in a second rotation direction, and then the voltage of the motor is disconnected to allow the motor to decelerate freely; when the motor decelerates to a stop, the current second initial zero angle of the motor is obtained; and a first average of the first initial zero angle and the second initial zero angle is determined as the initial zero angle of the motor.

[0086] In the embodiment of the present application, the processor may also be configured to:

[0087] An average of the first null angle and the second null angle is determined as a third null angle corresponding to the current carrier frequency.

[0088] In the embodiment of the present application, the processor may also be configured to:

[0089] When the motor is free-decelerating until the speed of the motor is zero, if the PI controller does not output the first zero-position angle, repeat steps S2 to S4 until the PI controller outputs the first zero-position angle; when the motor is free-decelerating until the speed of the motor is zero, if the PI controller does not output the second zero-position angle, repeat steps S5 to S8 until the PI controller outputs the second zero-position angle.

[0090] The present application also provides a motor, which may include the above-mentioned device for motor zero position calibration. Specifically, the motor also includes a PI regulator, and during the free deceleration of the motor, the PI controller uses the initial zero position angle as a reference to determine the zero position angle that makes the d-axis voltage of the motor zero.

[0091] An embodiment of the present application also provides a machine-readable storage medium, on which instructions are stored, and the instructions are used to enable a machine to execute the above-mentioned method for motor zero position calibration.

[0092] In one embodiment, a computer device is provided. The computer device may be a server, and its internal structure diagram may be as follows: Figure 6 As shown. The computer device includes a processor A01, a network interface A02, a memory (not shown in the figure) and a database (not shown in the figure) connected through a system bus. Among them, the processor A01 of the computer device is used to provide computing and control capabilities. The memory of the computer device includes an internal memory A03 and a non-volatile storage medium A04. The non-volatile storage medium A04 stores an operating system B01, a computer program B02 and a database (not shown in the figure). The internal memory A03 provides an environment for the operation of the operating system B01 and the computer program B02 in the non-volatile storage medium A04. The database of the computer device is used to store data for motor zero position calibration. The network interface A02 of the computer device is used to communicate with an external terminal through a network connection. When the computer program B02 is executed by the processor A01, a method for motor zero position calibration is implemented.

[0093] Those skilled in the art will understand that Figure 6 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than those shown in the figure, or combine certain components, or have a different arrangement of components.

[0094] Those skilled in the art will appreciate that the embodiments of the present application may be provided as methods, systems or computer program products. Therefore, the present application may adopt the form of a complete hardware embodiment, a complete software embodiment or an embodiment in combination with software and hardware. Moreover, the present application may adopt the form of a computer program product implemented on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) that contain computer-usable program code.

[0095] The present application is described with reference to the flowcharts and / or block diagrams of the methods, devices (systems), and computer program products according to the embodiments of the present application. It should be understood that each process and / or box in the flowchart and / or block diagram, as well as the combination of the processes and / or boxes in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to generate a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0096] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0097] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0098] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0099] The memory may include non-permanent memory in a computer-readable medium, random access memory (RAM) and / or non-volatile memory in the form of read-only memory (ROM) or flash RAM. The memory is an example of a computer-readable medium.

[0100] Computer readable media include permanent and non-permanent, removable and non-removable media that can be implemented by any method or technology to store information. Information can be computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology, compact disk read-only memory (CD-ROM), digital versatile disk (DVD) or other optical storage, magnetic cassettes, magnetic tape disk storage or other magnetic storage devices or any other non-transmission media that can be used to store information that can be accessed by a computing device. As defined herein, computer readable media does not include temporary computer readable media (transitory media), such as modulated data signals and carrier waves.

[0101] 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.

[0102] The above are only embodiments of the present application and are 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 within the scope of the claims of the present application.

Claims

1. A method for motor zero position calibration, characterized in that: The method comprises: Step S1: determining the initial zero angle of the motor; Step S2: inputting a first preset current into the motor at the current carrier frequency to drive the motor to rotate along a first rotation direction; Step S3: when the speed of the motor reaches the target speed, disconnecting the current of the motor so that the motor can decelerate freely; Step S4: During the free deceleration of the motor, the PI controller uses the initial zero angle as a reference to determine a first zero angle that makes the d-axis voltage of the motor zero; Step S5: inputting a second preset current into the motor to drive the motor to rotate along a second rotation direction; Step S6: when the speed of the motor reaches the target speed, disconnecting the current of the motor so that the motor can decelerate freely; Step S7: During the free deceleration of the motor, the PI controller uses the initial zero angle as a reference to determine a second zero angle that makes the d-axis voltage of the motor zero; Step S8: determining a third null angle corresponding to the current carrier frequency according to the first null angle and the second null angle; Step S9: Repeat steps S2 to S8 at different carrier frequencies to obtain target zero angles corresponding to different carrier frequencies, wherein the PI controller in the repeated steps S4 and S6 uses the third zero angle as a reference.

2. The method for motor zero position calibration according to claim 1, characterized in that: During the free speed reduction of the motor, the PI controller uses the initial zero angle as a reference to determine a first zero angle that makes the d-axis voltage of the motor zero, including: Setting the d-axis target voltage of the motor to zero; Obtaining a d-axis feedback voltage of the motor; Determine a voltage difference between a d-axis target voltage and a d-axis feedback voltage; Adjusting the zero angle based on the initial zero angle so that the voltage difference is zero; The zero angle when the voltage difference is zero is determined as the first zero angle.

3. The method for motor zero position calibration according to claim 1, characterized in that: During the free deceleration of the motor, the PI controller uses the initial zero angle as a reference to determine a second zero angle that makes the d-axis voltage of the motor zero, including: Setting the d-axis target voltage of the motor to zero; Obtaining a d-axis feedback voltage of the motor; Determine a voltage difference between a d-axis target voltage and a d-axis feedback voltage; Adjusting the zero angle based on the initial zero angle so that the voltage difference is zero; The zero angle when the voltage difference is zero is determined as the second zero angle.

4. The method for motor zero position calibration according to claim 1, characterized in that: Determining the initial zero angle of the motor comprises: Under the current carrier frequency, the d-axis voltage of the motor is set to a first preset voltage and the q-axis voltage of the motor is set to a second preset voltage to drive the motor to rotate in the first rotation direction, and then disconnect the voltage of the motor to allow the motor to decelerate freely; When the motor slows down to stop rotating, obtaining a current first initial zero angle of the motor; Setting the d-axis voltage of the motor to the second preset voltage and the q-axis voltage of the motor to the first preset voltage to drive the motor to rotate in the second rotation direction, and then disconnecting the voltage of the motor to allow the motor to decelerate freely; When the motor is decelerated to stop rotating, obtaining a current second initial zero angle of the motor; A first average of the first initial zero angle and the second initial zero angle is determined as an initial zero angle of the motor.

5. The method for motor zero position calibration according to claim 1, characterized in that: Determining a third null angle corresponding to the current carrier frequency according to the first null angle and the second null angle comprises: An average of the first null angle and the second null angle is determined as a third null angle corresponding to the current carrier frequency.

6. The method for motor zero position calibration according to claim 1, characterized in that: The method comprises: Acquire a sampling interval for a zero angle and an angular velocity of the motor within the sampling interval; Determine the actual time difference corresponding to other carrier frequencies according to the sampling interval and the current carrier frequency; The target null angle corresponding to the other carrier frequencies is updated according to the actual time difference and the angular velocity.

7. The method for motor zero position calibration according to claim 1, characterized in that: The method further comprises: In the process of the motor freely decelerating until the speed of the motor reaches zero, if the PI controller does not output the first zero angle, repeating steps S2 to S4 until the PI controller outputs the first zero angle; In the process of the motor freely decelerating until the speed of the motor reaches zero, if the PI controller does not output the second zero angle, steps S5 to S8 are repeatedly performed until the PI controller outputs the second zero angle.

8. A device for zero position calibration of a motor, characterized in that: include: a memory configured to store instructions; A processor is configured to call the instructions from the memory and implement the method for motor zero position calibration according to any one of claims 1 to 7 when executing the instructions.

9. A motor, characterized in that: It comprises the device for motor zero position calibration according to claim 8.

10. A machine-readable storage medium, characterized in that: The machine-readable storage medium stores instructions for enabling a machine to execute the method for motor zero position calibration according to any one of claims 1 to 7.

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