CN-122021204-A - Calculation method for no-load performance of embedded permanent magnet motor

CN122021204ACN 122021204 ACN122021204 ACN 122021204ACN-122021204-A

Abstract

The application discloses a calculation method of no-load performance of an embedded permanent magnet motor, which comprises the steps of obtaining motor parameters of the permanent magnet motor, wherein the motor parameters comprise a rotor initial position, calculating radian ranges of a magnetic pole area and a magnetic bridge area of the rotor based on the rotor initial position, calculating radian ranges of a pole slot area and a pole tooth area respectively, wherein the pole slot area is a circumferential overlapping area of the magnetic pole area and the stator slot area along the radial extension direction of the rotor, the pole tooth area is a circumferential overlapping area of the magnetic pole area and the stator tooth area along the radial extension direction of the rotor, calculating excitation magnetic flux, permanent magnet magnetic resistance, pole slot area magnetic resistance, pole tooth area magnetic resistance, magnetic leakage magnetic resistance and magnetic bridge area magnetic resistance in a first pole range of the permanent magnet motor based on a lumped parameter method, and calculating air gap magnetic density distribution of the pole slot area, the pole tooth area and the magnetic bridge area based on a magnetic circuit method. By the method, on the premise of ensuring the precision, the calculation efficiency of solving the air gap flux density distribution of each area is improved, and the complexity of designing the permanent magnet motor is simplified.

Inventors

SHI DAN
ZHOU AIJUN
WANG JIAN
WANG YIMENG
Xing Kaifu
Niu Jianjian

Assignees

浙江机电职业技术大学
德州恒力电机有限责任公司

Dates

Publication Date: 20260512
Application Date: 20260414

Claims (10)

1. The method for calculating the no-load performance of the embedded permanent magnet motor is characterized by comprising the following steps of: acquiring motor parameters of a permanent magnet motor, wherein the motor parameters comprise initial positions of rotors; Calculating the radian ranges of a magnetic pole region and a magnetic bridge region of the rotor based on the initial position of the rotor, and respectively calculating the radian ranges of a pole slot region and a pole tooth region, wherein the pole slot region is a circumferential overlapping region of the magnetic pole region and a stator slot region along the radial extending direction of the rotor, and the pole tooth region is a circumferential overlapping region of the magnetic pole region and a stator tooth region along the radial extending direction of the rotor; Based on a lumped parameter method, calculating excitation magnetic flux, permanent magnet magnetic resistance, pole slot area magnetic resistance, pole tooth area magnetic resistance, magnetic barrier leakage magnetic resistance and magnetic bridge area magnetic resistance in a first pole range of the permanent magnet motor, wherein the magnetic barrier leakage magnetic resistance is the magnetic resistance of a magnetic barrier; And calculating air gap flux density distribution of the pole slot region, the pole tooth region and the magnetic bridge region based on a magnetic circuit method, the radian range of the pole slot region and the magnetic bridge region of the rotor, the radian range of the pole slot region and the pole tooth region, the excitation magnetic flux, the magnetic bridge region magnetic resistance, the permanent magnet magnetic resistance, the pole slot region magnetic resistance, the pole tooth region magnetic resistance and the magnetic barrier leakage magnetic resistance.
2. The method of computing as recited in claim 1, wherein, The computing method further comprises the following steps: Determining the material relative permeability of the magnetic bridge region based on the air gap flux density distribution of the magnetic bridge region and the BH curve of the iron core; updating the relative magnetic permeability of the material of the magnetic bridge region based on a preset error convergence value; And calculating the magnetic resistance of the magnetic bridge region after updating based on the updated relative magnetic permeability of the material of the magnetic bridge region, and calculating the air gap magnetic density distribution of the magnetic bridge region after updating.
3. The method of calculation according to claim 1 or 2, characterized in that, The motor parameters include pole number and slot number; The computing method further comprises the following steps: And calculating the minimum symmetrical unit number, the minimum unit slot number and the minimum unit pole number of the permanent magnet motor based on the greatest common divisor of the pole number and the slot number.
4. The method of computing as claimed in claim 3, wherein, The calculation method comprises the following steps: outputting all the air gap flux density distribution when the minimum unit pole number is equal to 1; when the minimum unit pole number is greater than 1, the permanent magnet motor comprises an nth pole adjacent to an nth-1 pole, and n is a positive integer greater than 1 and equal to the minimum unit pole number; the calculation method comprises the following steps: When the minimum unit pole number is greater than 1, respectively calculating an air gap flux density distribution set of the pole groove region, the pole tooth region and the magnetic bridge region in the range from the second pole to the nth pole of the permanent magnet motor; determining an air gap flux density distribution curve in a range from a first pole to an n-th pole of the permanent magnet motor based on each air gap flux density distribution in the air gap flux density distribution set and all the air gap flux density distributions in the range from the first pole; Defining an area enclosed by the air gap flux density distribution curve with an abscissa axis and an ordinate larger than 0 as a first area, defining an area enclosed by the air gap flux density distribution curve with an abscissa axis and an ordinate smaller than 0 as a second area, and determining the offset of the air gap flux density distribution curve based on the difference between the first area and the second area; and based on the offset, updating an air gap flux density distribution curve in the range from the first pole to the n-th pole of the permanent magnet motor.
5. The method of computing as recited in claim 1, wherein, The magnetic pole area is the passing area of the main magnetic flux of the permanent magnet, and the magnetic bridge area is the covering area of the magnetism isolating bridge.
6. The method of computing as recited in claim 1, wherein, The motor parameters comprise the axial effective length of the motor, the outer radius of the rotor, the length of the air gap, the thickness of the magnetic barrier, the length of the magnetic barrier, the thickness of the magnetic isolation bridge and the length of the magnetic isolation bridge; The calculating the pole slot area magnetic resistance in the first pole range of the permanent magnet motor comprises the following steps: calculating the reluctance of the pole slot region based on vacuum permeability, the motor axial effective length, the rotor outer radius, the radian range of the stator slot region, and the air gap length; the calculating the pole tooth area magnetic resistance in the first pole range of the permanent magnet motor comprises the following steps: Calculating a reluctance of the tooth region based on a second product of vacuum permeability, the rotor outer radius, the motor axial effective length, a difference between a maximum value and a minimum value of an arc range of the tooth region, and based on a quotient of the air gap length and the second product; the calculating the flux-barrier leakage reluctance in the first pole range of the permanent magnet motor comprises the following steps: Calculating the magnetic barrier leakage reluctance based on a third product of vacuum magnetic permeability, the thickness of the magnetic barrier and the axial effective length of the motor and based on a quotient of the length of the magnetic barrier and the third product; the calculating the magnetic bridge region reluctance in the first pole range of the permanent magnet motor comprises: -calculating the magnetic resistance of the bridge region based on a fourth product of the vacuum permeability, the relative permeability of the magnetically isolated bridge material, the thickness of the magnetically isolated bridge and the axial effective length of the motor, and based on a quotient of the length of the magnetically isolated bridge and the fourth product.
7. The method of computing as recited in claim 6, wherein, The motor parameters comprise permanent magnet width, permanent magnet remanence, permanent magnet thickness and relative permeability of the permanent magnet; The calculating the excitation flux in the first pole range of the permanent magnet motor includes: calculating the excitation magnetic flux based on the product of the axial effective length of the motor, the width of the permanent magnet and the residual magnetism of the permanent magnet; the calculating the permanent magnet reluctance of the permanent magnet motor in the first pole range comprises: The permanent magnet reluctance is calculated based on a first product of vacuum permeability, relative permeability of the permanent magnet, the permanent magnet width, and the motor axial effective length, and based on a quotient of the permanent magnet thickness and the first product.
8. The method of computing as recited in claim 1, wherein, The motor parameters comprise the axial effective length of the motor and the outer radius of the rotor; the calculating of the air gap flux density distribution of the pole tooth area comprises the following steps: calculating a second quotient of the excitation magnetic flux and a fifth product based on a fifth product of the rotor outer radius, the motor axial effective length, and a difference of a maximum value and a minimum value of an arc range of the tooth region; calculating a third quotient of the magnetic bridge region reluctance and the second sum based on the second sum of the magnetic bridge region reluctance, the permanent magnet reluctance, the pole slot region reluctance, the pole tooth region reluctance, and the barrier drain reluctance; Calculating air gap flux density distribution of the pole tooth area based on the product of the second quotient and the third quotient; Or the calculating of the air gap flux density distribution of the pole tooth area comprises the following steps: calculating a bridge region flux based on a product of the excitation flux and the third quotient; and calculating the air gap flux density distribution of the pole tooth region based on the quotient of the magnetic bridge region magnetic flux and the fifth product.
9. The method of computing as recited in claim 8, wherein, The motor parameters include air gap length; the calculating of the air gap flux density distribution of the pole groove region comprises the following steps: calculating the magnetic path length of a magnetic path in the stator slot area based on the outer radius of the rotor and the radian range of the stator slot area; and calculating the air gap magnetic flux density distribution of the pole groove region based on a first quotient of the magnetic path length and the air gap length and a first sum of the first quotient and 1 and based on a quotient of the air gap magnetic flux density distribution of the pole tooth region and the first sum.
10. The method of computing as recited in claim 8, wherein, The motor parameters comprise the length of an air gap and the thickness of a magnetism isolating bridge; the calculating of the air gap flux density distribution of the magnetic bridge region comprises the following steps: And calculating the air gap flux density distribution of the magnetic bridge region based on the air gap flux density distribution of the pole tooth region, the rotor outer radius, the initial radian value of the radian range of the magnetic bridge region, the difference between the maximum value and the minimum value of the radian range of the magnetic bridge region, the air gap length, the thickness of the magnetism isolating bridge, the vacuum magnetic permeability and the material relative magnetic permeability of the magnetic bridge region.

Description

Calculation method for no-load performance of embedded permanent magnet motor Technical Field The application relates to the field of motor electromagnetic field analysis, in particular to a calculation method for no-load performance of an embedded permanent magnet motor. Background The embedded permanent magnet motor is a permanent magnet synchronous motor with permanent magnets embedded in a rotor, and when the embedded permanent magnet motor is designed, an empty-load air-gap field is a core carrier of electromagnetic performance of the embedded permanent magnet motor, and the distribution characteristics (such as harmonic content and the like) of the empty-load air-gap field directly influence key performance indexes such as torque density, efficiency and the like of the embedded permanent magnet motor. The distribution of the air gap flux density can describe the specific numerical distribution of the magnetic field in the air gap, and data support is provided for the design of the embedded permanent magnet motor. If the air gap flux density distribution of the embedded permanent magnet motor is calculated through finite element simulation, on one hand, the embedded permanent magnet motor needs to be modeled, boundary conditions are set, the built model is meshed, the calculation process is complex, the calculation speed is low, on the other hand, once the mistakes occur in any step in the process, the risk of non-convergence exists, the simulation needs to be carried out again, the overall efficiency is reduced, and if the calculation is carried out through a magnetic circuit method, the calculation accuracy is low. What is needed is a method for calculating the empty load performance of an embedded permanent magnet motor, which can improve the calculation efficiency of solving the air gap flux density distribution of each region and simplify the complexity of designing the embedded permanent magnet motor on the premise of ensuring the precision. Disclosure of Invention In order to solve the defects in the prior art, the application aims to provide a calculation method for the no-load performance of an embedded permanent magnet motor, which can improve the calculation efficiency of solving the air gap magnetic density distribution of each area on the premise of ensuring the precision and simplify the complexity of designing the permanent magnet motor. The embodiment of the application provides a calculation method of no-load performance of an embedded permanent magnet motor, which comprises the steps of obtaining motor parameters of the permanent magnet motor, wherein the motor parameters comprise a rotor initial position, calculating radian ranges of a magnetic pole region and a magnetic bridge region of the rotor based on the rotor initial position, respectively calculating radian ranges of a pole slot region and a pole tooth region, wherein the pole slot region is a circumferential overlapping region of the magnetic pole region and a stator slot region along the radial extension direction of the rotor, the pole tooth region is a circumferential overlapping region of the magnetic pole region and the stator tooth region along the radial extension direction of the rotor, calculating excitation magnetic flux, permanent magnet magnetic resistance, pole slot region magnetic resistance, pole tooth region magnetic resistance, magnetic leakage magnetic resistance and magnetic bridge region magnetic resistance in a first pole range of the permanent magnet motor based on a lumped parameter method, and calculating magnetic barrier magnetic leakage magnetic resistance as magnetic resistance of the magnetic bridge region, and magnetic barrier magnetic gap distribution of the pole slot region, the magnetic barrier magnetic resistance and the magnetic bridge region based on a magnetic circuit method, the magnetic pole region and the magnetic bridge region of the rotor, the magnetic barrier region of the pole slot region magnetic resistance, the magnetic barrier magnetic resistance and the magnetic barrier magnetic tooth region. In some implementations, the computing method further includes determining a material relative permeability of the magnetic bridge region based on the air gap flux density distribution of the magnetic bridge region and a BH curve of the iron core, updating the material relative permeability of the magnetic bridge region based on a preset error convergence value, computing an updated magnetic resistance of the magnetic bridge region based on the updated material relative permeability of the magnetic bridge region, and computing the updated air gap flux density distribution of the magnetic bridge region. In some implementations, the motor parameters include a number of poles and a number of slots, and the method of calculating further includes calculating a minimum number of symmetric units, a minimum number of unit slots, and a minimum number of unit poles of the permanent magnet motor based