Automatic calibration method, system and storage medium for permanent magnet synchronous motor position sensor

Abstract

This invention discloses an automatic calibration method for a position sensor of a permanent magnet synchronous motor, comprising: providing a gradually increasing d-axis voltage; sequentially setting the control angle to 0°, 60°, and 300° under different d-axis voltages; detecting the error between the control angle and the measured angle; if the requirements are not met, repeating the process; if the requirements are met, determining the zero-position calibration value and automatically writing it into the motor controller. In the automatic calibration process of this invention, after each setting of the control angle, it checks whether the current value is overloaded; if overloaded, the process ends and a calibration failure message is displayed; if not overloaded, the process continues. During the angle determination process, a counting delay is applied before each measurement, and multiple measurements are taken and the average value is calculated, thereby reducing the measurement error.

Description

Technical Field

[0001] This invention relates to the automotive field, and in particular to an automatic calibration method for a permanent magnet synchronous motor position sensor, and an automatic calibration system for performing the automatic calibration method for the permanent magnet synchronous motor position sensor. Background Technology

[0002] Currently, for the precise control of permanent magnet synchronous motors, especially automotive braking permanent magnet synchronous motors, key indicators include the smoothness and rapid response of motor torque. In the precise control of permanent magnet synchronous motors, it is necessary to obtain the motor rotor's position signal in real time. Currently, position sensors are commonly used to acquire the real-time position of the motor rotor. After installation, the initial position of the position sensor needs to be determined, i.e., zero-position calibration of the position sensor is required. The accuracy of the initial position directly affects the smoothness and rapid response of the motor torque.

[0003] The existing method for zero-point calibration of position sensors involves first using the directly measured zero-point value as a compensation value for the sensor's detection signal. Then, the motor is dragged to a certain speed in both forward and reverse directions, with the compensation value being fine-tuned while the motor torque value is read. This process continues until the torque values ​​for both forward and reverse rotations are close to zero; this compensation value is then considered the precise zero-point calibration value. Generally, this zero-point calibration method requires the use of a motor torque sensor, increasing the cost and reducing calibration efficiency. Summary of the Invention

[0004] The summary of this invention introduces a series of simplified concepts, all of which are simplifications of existing technologies in the field, and will be further explained in detail in the detailed description section. This summary is not intended to limit the key features and essential technical features of the claimed technical solution, nor is it intended to determine the scope of protection of the claimed technical solution.

[0005] The technical problem to be solved by the present invention is to provide an automatic calibration method for a permanent magnet synchronous motor position sensor that can avoid hardware damage caused by motor failure during the zero-position calibration process and improve the zero-position calibration efficiency of the permanent magnet synchronous motor position sensor.

[0006] And an automatic calibration system for performing the automatic calibration method for the permanent magnet synchronous motor position sensor. To solve the above-mentioned technical problems, the present invention provides an automatic calibration method for a permanent magnet synchronous motor position sensor, comprising the following steps: Step 1: Apply a specified positive voltage Ud to the D-axis of the permanent magnet synchronous motor, set the Q-axis voltage to 0, and set the control angle to 0°. Step 2: Read the three-phase currents (A, B, and C) of the motor in real time; If any of the following conditions occurs: A-phase current IA > Imax, B-phase current IB > Imax, or C-phase current IC > Imax, then calibration failure will be indicated and the D-axis voltage will be set to 0; Imax is the maximum current that the motor can withstand under stall conditions. Step 3: After waiting for N1 counts, begin recording the angle derived from the position sensor signal. The angle value will be resolved over time. The coarse scale value of the motor zero position is calculated. After waiting for N2 counts, Record it; N2≥N1>0; Step 4: Keeping the D-axis positive voltage and Q-axis 0 voltage constant, set the control angle to 60°, and repeat steps 2 and 3 to obtain the measurement angle corresponding to the control angle of 60°. ; Step 5: After the N2 count is reached, apply the specified positive voltage Ud to the D-axis of the permanent magnet synchronous motor again, set the Q-axis voltage to 0, and set the angle to 0°. Repeat step 2 to obtain the measured angle. ,like Then proceed to step six; otherwise, return to step one. Allowable deviation; Step 6: Keeping the D-axis positive voltage and Q-axis 0 voltage constant, set the control angle to 300°, and repeat steps 2 and 3 to obtain the measured angle. ; Step 7: After the N2 count is reached, apply a positive voltage Ud to the D-axis of the permanent magnet synchronous motor again, set the Q-axis voltage to 0, and set the angle to 0 degrees. Repeat steps 2 and 3 to obtain the angle. ,like Then proceed to step eight; otherwise, return to step one. Step 8, when If the condition is met, proceed to step nine; otherwise, return to step one. This is the maximum zero-position error value; Step 9: Calculate the zero position of the motor position sensor. ,Will The data is automatically written into the motor controller, and the calibration is complete.

[0007] Optionally, the specified positive voltage Ud is determined by the following formula; Formula 1: Ud = Ud0 + n * Udu; Udu is the unit increment, and Ud0 is the initial D-axis voltage; The value of n in Formula 1 is determined by the following Formula 2: Formula 2: n = n + 1; n is initially 0.

[0008] Alternatively, the coarse value of the motor's zero position can be calculated using Formula 3. ; Formula 3: ; In the formula, k is a constant.

[0009] Optionally, the zero position of the motor position sensor can be calculated using Formula 4. ; Formula 4: .

[0010] The present invention provides a computer-readable storage medium having a program stored therein, which, when executed, implements the steps in the automatic calibration method for the position sensor of the permanent magnet synchronous motor.

[0011] This invention provides an automatic calibration system for the automatic calibration method of the position sensor of a permanent magnet synchronous motor described in any one of the above-mentioned methods, comprising: A given unit is used to specify the d-axis input voltage and the q-axis voltage; The calculation unit is used to calculate and determine the error of the measurement angle based on the position output signal and coarse calibration value of the position sensor; The control unit is used to control the permanent magnet synchronous motor using vector control based on the d-axis and q-axis voltages; The acquisition unit is used to acquire the three-phase current under control and determine whether the three-phase current is overloaded. An adjustment unit is used to increase the d-axis voltage ud according to the error amount described by the calculation unit and send it to the given unit.

[0012] Compared with the prior art, the present invention can achieve at least the following technical effects: 1. The entire calibration process can be controlled by an automatic program, eliminating the need for manual calibration of the zero position, which speeds up the calibration of the motor position sensor. Multiple calibrations and verifications also increase the accuracy of the zero position.

[0013] 2. Considering the uncertainty of the load state during motor calibration, an adaptive adjustment function for the D-axis voltage has been added to avoid calibration failure caused by the motor failing to operate when the load is too large. At the same time, a delay has been added to prevent incorrect zero-position calibration during motor oscillation.

[0014] 3. Monitoring of positioning angle error and current enables self-diagnosis of zero-position calibration, which can prevent damage to the motor and hardware during the calibration process, improve reliability, and alert the calibrator to motor and hardware faults, reducing potential subsequent losses. Attached Figure Description

[0015] The accompanying drawings are intended to illustrate the general characteristics of the methods, structures, and / or materials used in specific exemplary embodiments of the invention, supplementing the description in the specification. However, the drawings are schematic diagrams not drawn to scale and may not accurately reflect the precise structural or performance characteristics of any of the given embodiments. The drawings should not be construed as limiting or restricting the range of numerical values ​​or properties covered by exemplary embodiments of the invention. The invention will now be described in further detail with reference to the accompanying drawings and specific embodiments: Figure 1 This is a flowchart of the method of the present invention.

[0016] Figure 2 This is the system control block diagram of the present invention. Detailed Implementation

[0017] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can fully understand other advantages and technical effects of the present invention from the content disclosed in this specification. The present invention can also be implemented or applied through different specific embodiments, and the details in this specification can also be applied based on different viewpoints, with various modifications or changes made without departing from the overall design concept of the invention. It should be noted that, unless otherwise specified, the following embodiments and features can be combined with each other. The following exemplary embodiments of the present invention can be implemented in many different forms and should not be construed as being limited to the specific embodiments set forth herein. It should be understood that these embodiments are provided to make the disclosure of the present invention thorough and complete, and to fully convey the technical solutions of these exemplary embodiments to those skilled in the art.

[0018] First embodiment; This invention provides an automatic calibration method for a position sensor of a permanent magnet synchronous motor. A two-phase rotating coordinate system dq is established on the rotor of the permanent magnet synchronous motor. This coordinate system dq rotates synchronously with the rotor. The d-axis represents the direction of the rotor's magnetic field, and the q-axis represents the direction perpendicular to the rotor's magnetic field. The position of the permanent magnet synchronous motor rotor is defined as... .

[0019] like Figure 1 As shown, the automatic zero-position calibration method for the permanent magnet synchronous motor position sensor includes the following steps: Step 1: Given the d-axis voltage as Ud and the q-axis voltage as 0.

[0020] Specifically, when the permanent magnet synchronous motor enters the zero-position automatic calibration process, a small voltage Ud0 is applied to the d-axis, and the d-axis voltage Ud is gradually increased by a small amount Udu in subsequent steps; Step 2: Obtain the three-phase current under control and determine whether the three-phase current is overloaded; Specifically, the standard for judging whether the three-phase current is overloaded is the maximum current that the motor can withstand under stall conditions.

[0021] Step 3: Analyze and calculate the coarse zero-position value of the motor. And record it; The zero-position coarse scale value of the motor position is obtained through an analytical calculation method for the motor position. This method involves waiting for N1 counts before starting to record the angle derived from the position sensor signal. The angle value will be resolved over time. The measured angle of the motor position is calculated using Formula 3. After waiting for N2 counts, Write it down.

[0022] In the formula, k is a constant; Step four: Keeping the d-axis positive voltage and q-axis 0 voltage constant, set the control angle to 60°. Determine whether the three-phase current is overloaded using the method described in step two. Obtain the corresponding measurement angle at a control angle of 60° using the analytical calculation method for motor position. ; Step 5: Repeat the method described in Step 3 to obtain the coarse zero-bit value. And based on the coarse standard value and the angle measurement described in step four Determine the error status; Specifically, the allowable error value is set to... If satisfied If so, the error is within the acceptable range; Step 6: Keeping the D-axis positive voltage and Q-axis 0 voltage constant, set the control angle to 300°. Determine if the three-phase current is overloaded using the method described in Step 2. Obtain the measurement angle corresponding to the control angle of 300° using the analytical calculation method of motor position. ; Step 7: Repeat the method described in Step 3 to obtain the coarse zero-bit value. And based on the coarse standard value and the angle measurement described in step six Determine the error status; the method for determining the error status is the same as described in step five. Step 8: Determine the error status of the zero-position coarse calibration values ​​measured in Steps 3, 5, and 7; Specifically, when At that time, the error was within the allowable range, where This is the maximum zero-position error value.

[0023] The steps in the method of the first embodiment of the present invention can control the hardware to realize the entire calibration process through computer programming technology, which speeds up the calibration speed of the motor position sensor. At the same time, considering the uncertainty of the load state during motor calibration and the oscillation error of the position sensor, the function of adaptive adjustment of D-axis voltage and delayed measurement is added, which avoids damage to the motor and hardware during the calibration process, improves reliability, and can also indicate to the calibrator that there is a fault in the motor and hardware, reducing possible subsequent losses.

[0024] Second embodiment; The present invention provides a computer-readable storage medium having a program stored therein, which, when executed, implements the steps in the automatic calibration method for the position sensor of a permanent magnet synchronous motor described in the first embodiment.

[0025] Third embodiment; This invention provides an automatic calibration system for the automatic calibration method of the permanent magnet synchronous motor position sensor described in the first embodiment, which can be implemented by combining computer programming technology with existing hardware, including: A given unit is used to specify the d-axis input voltage and the q-axis voltage; The calculation unit is used to calculate and determine the error of the measurement angle based on the position output signal and coarse calibration value of the position sensor; The control unit is used to control the permanent magnet synchronous motor using vector control based on the d-axis and q-axis voltages; The acquisition unit is used to acquire the three-phase current under control and determine whether the three-phase current is overloaded. An adjustment unit is used to increase the d-axis voltage ud according to the error amount described by the calculation unit and send it to the given unit.

[0026] Unless otherwise defined, all terms used herein (including technical and scientific terms) shall have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It will also be understood that, unless explicitly defined herein, terms such as those defined in a general dictionary shall be interpreted as having the meaning consistent with their meaning in the relevant field context, and not as having an idealized or overly formal meaning.

[0027] The present invention has been described in detail above through specific embodiments and examples, but these are not intended to limit the invention. Many modifications and improvements can be made by those skilled in the art without departing from the principles of the invention, and these should also be considered within the scope of protection of the present invention.

Claims

1. An automatic calibration method for a position sensor of a permanent magnet synchronous motor, characterized in that, Includes the following steps: Step 1: Apply a specified positive voltage Ud to the D-axis of the permanent magnet synchronous motor, set the Q-axis voltage to 0, and set the control angle to 0°. Step 2: Read the three-phase currents (A, B, and C) of the motor in real time; If any of the following conditions occur: A-phase current IA>Imax, B-phase current IB>Imax, or C-phase current IC>Imax, then a calibration failure will be indicated and the D-axis voltage will be set to 0; Imax is the maximum current that the motor can withstand under stall conditions. Step 3: After waiting for N1 counts, begin recording the angle derived from the position sensor signal. The angle value will be resolved over time. The coarse value of the motor zero position is calculated. After waiting for N2 counts, Write it down; Step 4: Keeping the D-axis positive voltage and Q-axis 0 voltage constant, set the control angle to 60°, and repeat steps 2 and 3 to obtain the measurement angle corresponding to the control angle of 60°. ; Step 5: After the N2 count is reached, apply the specified positive voltage Ud to the D-axis of the permanent magnet synchronous motor again, set the Q-axis voltage to 0, and set the angle to 0°. Repeat step 2 to obtain the measured angle. ,like Then proceed to step six; otherwise, return to step one. Allowable deviation; Step 6: Keeping the D-axis positive voltage and Q-axis 0 voltage constant, set the control angle to 300°, and repeat steps 2 and 3 to obtain the measured angle. ; Step 7: After the N2 count reaches its maximum, apply a positive voltage Ud to the D-axis of the permanent magnet synchronous motor again, set the Q-axis voltage to 0, and set the angle to 0 degrees. Repeat steps 2 and 3 to obtain the angle. ,like Then proceed to step eight; otherwise, return to step one. Step 8, when If the condition is met, proceed to step nine; otherwise, return to step one. This is the maximum zero-position error value; Step 9: Calculate the zero position of the motor position sensor. ,Will The data is automatically written to the motor controller, and the calibration is complete. The zero position of the motor position sensor is calculated using Formula 4. ; Formula 4: .

2. The automatic calibration method for the position sensor of a permanent magnet synchronous motor as described in claim 1, characterized in that: The specified positive voltage Ud is determined by the following formula; Formula 1: Ud = Ud0 + n * Udu; Udu is the unit increment, and Ud0 is the initial D-axis voltage; The value of n in Formula 1 is determined by the following Formula 2: Formula 2: n = n + 1; n is initially 0.

3. The automatic calibration method for the position sensor of a permanent magnet synchronous motor as described in claim 1, characterized in that: The coarse value of the motor's zero position is calculated using Formula 3. ; Formula 3: ; In the formula, k is a constant.

4. A computer-readable storage medium, characterized in that: It internally stores a program, which, when executed, implements the steps in the automatic calibration method for the position sensor of the permanent magnet synchronous motor according to any one of claims 1-3.

5. An automatic calibration system for performing the automatic calibration method for a permanent magnet synchronous motor position sensor according to any one of claims 1-3, characterized in that, include: A given unit is used to specify the d-axis input voltage and the q-axis voltage; The calculation unit is used to calculate and determine the error of the measurement angle based on the position output signal and coarse calibration value of the position sensor; The control unit is used to control the permanent magnet synchronous motor using vector control based on the d-axis and q-axis voltages; The acquisition unit is used to acquire the three-phase current under control and determine whether the three-phase current is overloaded. The adjustment unit increases the d-axis voltage ud based on the error provided by the calculation unit and sends it to the given unit.

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