Permanent magnet synchronous motor with rotor ideal sine wave air-gap magnetic field

Abstract

The invention discloses a permanent magnet synchronous motor with a rotor ideal sine wave air-gap magnetic field, and belongs to a permanent magnet motor. The permanent magnet synchronous motor is characterized by unique design of a rotor magnetic path structure and an outer edge line of a pole shoe. The principle of the permanent magnet synchronous motor is feasible in terms of theory and the implementation process is not complex; a comparison test result of a sample machine prepared by the scheme proves that the permanent magnet synchronous motor with the rotor ideal sine wave air-gap magnetic field can eliminate all odd harmonics, has more excellent performance than the commonly-adopted permanent magnet synchronous motor with a rotor square wave air-gap magnetic field, higher motor efficiency and lower temperature rise, and can greatly lower torque fluctuation and electromagnetic noise.

Description

technical field [0001] The invention belongs to a permanent magnet motor, and relates to a high-power permanent magnet motor for an electric vehicle, in particular to a permanent magnet synchronous motor with an ideal sine wave air gap magnetic field of a rotor. Background technique [0002] Most of the driving motors used in high-end pure electric cars and pure electric cars are permanent magnet synchronous motors. For this kind of permanent magnet synchronous drive motors, although their performance parameters can meet the standards implemented by the automotive industry, it is far from people's expectations. There is still a gap in expectations. With the development of society and the continuous improvement of living standards, there is a need for a motor that is quieter and more comfortable than the current electric vehicle drive motor. A quiet and comfortable motor mainly means that the motor should not have torque fluctuations and electromagnetic noise during operatio...

AI Technical Summary

Problems solved by technology

[0003] At present, the rotor magnetic circuit structure adopted by most permanent magnet synchronous drive motors for electric vehicles is a square-wave air-gap magnetic field with equal air-gap length. The square-wave air-gap magnetic field contains a large number of odd harmonics. The technical methods of wave mainly include: First, use stator winding star connection or 120° electrical angle short-distance winding to eliminate the 3rd and 3rd multiple harmonics in the back electromotive force. , 7th, 11th and other harmonics have no effect, and are only limited to star connection, the short-pitch coefficient of 120° short-pitch winding is only 0.866, the loss of electromagnetic torque is too large, it is not advisable

Second, distributed windings, double-layer short-pitch windings, and slanted poles are used to reduce the amplitude of all odd harmonics, but these methods can only reduce odd harmonics, and cannot eliminate them. Moreover, some of these methods cannot be simultaneously Adoption, some of them will be difficult to adopt, such as the double-layer short-pitch winding, when the power supply voltage is high, it is necessary to do phase-to-phase or inter-turn insulation in the slot, which is difficult to implement

Therefore, it can be said that the permanent magnet synchronous motors currently used in electric vehicles inevitably have the problem of odd harmonics in the back electromotive force. If there are odd harmonics, there will be torque fluctuations and electromagnetic noise.

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