Zero calibration method for permanent magnet synchronous motor rotor with limited rotation range

Abstract

The invention relates to the technical field of motor control, in particular to a permanent magnet synchronous motor rotor zero calibration method with a limited rotation range, and the method comprises the steps: equally dividing a 360-degree electrical angle into N parts according to the number of pole pairs of a motor and the angle of a rotatable range, and obtaining N + 1 electrical angle sequences; under the two-phase static coordinate system of the motor, N + 1 energization sequences are injected, after each energization sequence is energized for a period of time, the reading of the absolute encoder is recorded, and accordingly the rotating electrical angle of the motor rotor between the two adjacent energization sequences is obtained; and analyzing the electrical angle of rotation of the motor rotor between two adjacent power-on sequences to obtain the reading of the absolute encoder when the motor rotor is at the known electrical angle, and further obtain the reading of the absolute encoder when the motor rotor is at the zero position. According to the invention, calibration of the absolute encoder reading corresponding to the zero position of the motor rotor can be completed rapidly and accurately.

Description

Technical Field

[0001] The invention relates to the technical field of motor control, and in particular to a method for zero-position calibration of a permanent magnet synchronous motor rotor with a limited rotation range. Background Art

[0002] Space vector control is a commonly used drive control method for permanent magnet synchronous motors, and the acquisition of the motor rotor position is the basis of space vector control. The rotor position of a permanent magnet synchronous motor is usually obtained by an absolute encoder. To obtain the motor rotor position from the absolute encoder reading, it is necessary to know the absolute encoder reading corresponding to the motor rotor at zero position, that is, the motor rotor zero position needs to be calibrated in advance. The pre-positioning method is to energize the motor so that its rotor is locked to zero position, which is a commonly used rotor zero position calibration method. However, for mechanisms with limited rotation range, it may not be possible to lock the motor rotor to zero position, and it is also impossible to obtain the range of the rotor electrical angle within the limited rotation range in advance, and there is a risk that the rotor zero position calibration cannot be completed. Summary of the invention

[0003] In order to solve the above technical problems, the present invention provides a method for calibrating the rotor zero position of a permanent magnet synchronous motor with a limited rotation range. Compared with the pre-positioning method, which requires the rotor to be locked to the zero position, the present invention does not require the rotor to be locked to the zero position, nor does it require the range of the rotor electrical angle within the limited rotation range to be obtained in advance, so as to complete the calibration of the rotor zero position.

[0004] The object of the present invention is to provide a method for zero position calibration of a permanent magnet synchronous motor rotor with a limited rotation range, comprising: Step 1: Divide the 360° electrical angle into N parts according to the number of motor pole pairs and the angle of rotation range, and obtain an electrical angle sequence of N+1; Step 2: In the motor two-phase stationary coordinate system In this case, N+1 power-on sequences are injected, each of which is powered on for a period of time, and the reading of the absolute encoder is recorded; Step 3: Calculate the electrical angle that the motor rotor rotates between two adjacent power-on sequences, analyze the electrical angle that has been rotated, and obtain the absolute encoder reading of the motor rotor position at one electrical angle; Step 4: Calculate the reading of the absolute encoder when the motor rotor is at zero position to complete the calibration of the motor rotor zero position.

[0005] Preferably, the method for acquiring the N+1 electrical angle sequences includes: The number of parts N that the 360° electrical angle is divided into is Round up, where P is the number of motor pole pairs, is the angle of the rotation range; When N is an even number, N is not processed; When N is an odd number, , convert N into an even number; Divide the 360° electrical angle into N equal parts to obtain a sequence of N+1 electrical angles. satisfy .

[0006] Preferably, the method for obtaining readings of an absolute encoder comprises: In the motor two-phase stationary coordinate system Next, N+1 energized series are injected sequentially. , the power-on voltage of each power-on sequence is: , in is the electrical angle in the electrical angle sequence; After each power-on sequence has been powered on for a period of time, the current reading of the absolute encoder is recorded as the power-on angle. The absolute encoder readings at the time are obtained to obtain a numerical sequence of absolute encoder readings of N+1 .

[0007] Preferably, a method for obtaining a reading of an absolute encoder when the motor rotor position is at an electrical angle comprises: Reading sequence of values ​​using absolute encoder , the absolute encoder readings corresponding to two adjacent power-on sequences are subtracted to obtain a number N of absolute encoder reading difference sequences ,satisfy , and obtain the electrical angle sequence of the motor rotor between two adjacent power-on sequences, which is N in number ,satisfy , where P is the number of motor pole pairs, F is the maximum reading of the absolute encoder, The corresponding two energized electrical angles are and ; The electrical angle sequence of the motor rotor between two adjacent power-on sequences Conduct analysis, like The absolute value of does not satisfy , then the motor rotor position is in electrical degrees The reading of the corresponding absolute encoder is currently unavailable; like The absolute value of , then the motor rotor position is in electrical angle When the corresponding absolute encoder reading is , complete the calibration of the absolute code disk reading when the motor rotor position is at one electrical angle.

[0008] Preferably, the method for obtaining the absolute encoder reading when the motor rotor is at zero position comprises: Get the motor rotor position in electrical degrees When the absolute encoder reads , the reading of the absolute encoder when the motor rotor is at zero position is calculated to be .

[0009] The present invention has at least the following beneficial effects: The present invention provides a method for calibrating the zero position of a permanent magnet synchronous motor rotor with a limited rotation range. The present invention is a method for obtaining the absolute encoder reading of a motor rotor of a mechanism with a limited rotation range driven by a permanent magnet synchronous motor when the motor rotor is at zero position. By sequentially injecting a certain number of power-on sequences, recording and analyzing the electrical angles rotated by the electronic rotor between adjacent power-on sequences, the reading of the absolute encoder at a known electrical angle can be obtained, and then the reading of the absolute encoder when the motor rotor is at zero position can be calculated. The present invention does not require the rotor to be locked to zero position, nor does it require the electrical angle range within the limited rotation range to be obtained in advance, and the rotor zero position calibration can be completed. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] Figure 1 It is a flow chart of permanent magnet synchronous motor rotor zero position calibration.

[0011] Figure 2 is the stationary coordinate system of the permanent magnet synchronous motor Schematic diagram of . DETAILED DESCRIPTION

[0012] In order to illustrate the technical means and effects adopted by the present invention to achieve the predetermined purpose of the invention, the following is a detailed description in conjunction with embodiments.

[0013] The purpose of the present invention is to provide a method for calibrating the zero position of a permanent magnet synchronous motor rotor with a limited rotation range. According to the present invention, the calibration of the motor rotor zero position corresponding to the absolute encoder reading can be completed quickly and accurately.

[0014] To achieve the above purpose, see Figure 1 As shown, a method for zero position calibration of a permanent magnet synchronous motor rotor with a limited rotation range comprises: Step 1: Divide the 360° electrical angle into N parts according to the number of motor pole pairs and the angle of the rotatable range, and obtain an electrical angle sequence of N+1; Step 2: In the motor two-phase stationary coordinate system In this case, N+1 power-on sequences are injected, each of which is powered on for a period of time, and the reading of the absolute encoder is recorded; Step 3: Calculate the electrical angle that the motor rotor rotates between two adjacent power-on sequences, analyze the electrical angle that has been rotated, and obtain the reading of the absolute encoder when the motor rotor position is at a known electrical angle; Step 4: Calculate the reading of the absolute encoder when the motor rotor is at zero position to complete the calibration of the motor rotor zero position.

[0015] The method for obtaining the electrical angle sequence in step 1 is: the number of motor pole pairs is P, and the angle of the rotatable range is , the number of equal parts of 360° electrical angle is N Round up; when N is an even number, N is not processed; when N is an odd number, , convert N into an even number; divide the 360° electrical angle into N parts, and obtain an electrical angle sequence of N+1. satisfy .

[0016] The absolute encoder reading acquisition method in step 2 is as follows: Figure 2 The motor two-phase stationary coordinate system shown Next, N+1 energized series are injected sequentially. , the power-on voltage of each power-on sequence is ,in is the electrical angle in the electrical angle sequence obtained in step 1; After each power-on sequence has been powered on for a period of time, the current reading of the absolute encoder is recorded as the power-on angle. The absolute encoder readings at the time are obtained to obtain a numerical sequence of absolute encoder readings of N+1 .

[0017] The method for obtaining an absolute encoder reading when the rotor electrical angle is known in step 3 is: using the absolute encoder reading value sequence obtained in step 2 , the absolute encoder readings corresponding to two adjacent power-on sequences are subtracted to obtain a number N of absolute encoder reading difference sequences ,satisfy , and then obtain the electrical angle sequence of the motor rotor between two adjacent power-on sequences, which is N in number ,satisfy , where P is the number of motor pole pairs, F is the maximum reading of the absolute encoder, The corresponding two energized electrical angles are and ; The electrical angle sequence of the motor rotor between two adjacent power-on sequences For analysis, if The absolute value of does not satisfy , then the motor rotor position is in electrical degrees , the corresponding absolute encoder reading is currently unavailable; if The absolute value of , then the motor rotor position is in electrical angle When the corresponding absolute encoder reading is , complete the calibration of the absolute code disk reading when the motor rotor position is at a known electrical angle.

[0018] The method for obtaining the absolute encoder reading when the motor rotor is at zero position in step 4: the motor rotor position in electrical degrees is obtained in step 3 When the absolute encoder reads , the reading of the absolute encoder when the motor rotor is at zero position is calculated to be .

[0019] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for zero position calibration of a permanent magnet synchronous motor rotor with a limited rotation range, characterized in that: include: Step 1: Divide the 360° electrical angle into N parts according to the number of motor pole pairs and the angle of rotation range, and obtain an electrical angle sequence of N+1; Step 2: In the motor two-phase stationary coordinate system In this case, N+1 power-on sequences are injected, each of which is powered on for a period of time, and the reading of the absolute encoder is recorded; Step 3: Calculate the electrical angle that the motor rotor rotates between two adjacent power-on sequences, analyze the electrical angle that has been rotated, and obtain the absolute encoder reading of the motor rotor position at one electrical angle; Step 4: Calculate the reading of the absolute encoder when the motor rotor is at zero position to complete the calibration of the motor rotor zero position.

2. The method for zero position calibration of a permanent magnet synchronous motor rotor with limited rotation range according to claim 1, characterized in that: The method for acquiring N+1 electrical angle sequences includes: The number of parts N that the 360° electrical angle is divided into is Round up, where P is the number of motor pole pairs, is the angle of the rotation range; When N is an even number, N is not processed; When N is an odd number, , convert N into an even number; Divide the 360° electrical angle into N equal parts to obtain a sequence of N+1 electrical angles. satisfy .

3. The method for zero position calibration of a permanent magnet synchronous motor rotor with limited rotation range according to claim 2, characterized in that: The method for obtaining the reading of the absolute encoder includes: In the motor two-phase stationary coordinate system Next, N+1 energized series are injected sequentially. , the power-on voltage of each power-on sequence is: ， in is the electrical angle in the electrical angle sequence; After each power-on sequence has been powered on for a period of time, the current reading of the absolute encoder is recorded as the power-on angle. The absolute encoder readings at the time are obtained to obtain a numerical sequence of absolute encoder readings of N+1 .

4. The method for zero position calibration of a permanent magnet synchronous motor rotor with limited rotation range according to claim 3, characterized in that: The method for obtaining the reading of the absolute encoder when the motor rotor position is one electrical angle includes: Reading sequence of values ​​using absolute encoder , the absolute encoder readings corresponding to two adjacent power-on sequences are subtracted to obtain a number N of absolute encoder reading difference sequences ,satisfy , and obtain the electrical angle sequence of the motor rotor between two adjacent power-on sequences, which is N in number ,satisfy , where P is the number of motor pole pairs, F is the maximum reading of the absolute encoder, The corresponding two energized electrical angles are and ; The electrical angle sequence of the motor rotor between two adjacent power-on sequences Conduct analysis, like The absolute value of does not satisfy , then the motor rotor position is in electrical degrees The reading of the corresponding absolute encoder is currently unavailable; like The absolute value of , then the motor rotor position is in electrical angle When the corresponding absolute encoder reading is , complete the calibration of the absolute code disk reading when the motor rotor position is at one electrical angle.

5. The method for zero position calibration of a permanent magnet synchronous motor rotor with limited rotation range according to claim 4, characterized in that: The method for obtaining the absolute encoder reading when the motor rotor is at zero position includes: Get the motor rotor position in electrical degrees When the absolute encoder reads , the reading of the absolute encoder when the motor rotor is at zero position is calculated to be .

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