Hybrid magnetic circuit low harmonic multi-stator field-weakening extended-speed permanent magnet synchronous motor and method thereof

Abstract

The invention discloses a hybrid magnetic circuit low harmonic wave multi-stator flux-weakening speed extension permanent magnet synchronous motor, and a method thereof. The hybrid magnetic circuit low harmonic wave multi-stator flux-weakening speed extension permanent magnet synchronous motor includes a radial stator, an axial stator and a rotor, wherein the rotor is arranged in the radial stator, and is arranged coaxially with the radial stator; the axial stator is arranged at the end part of the rotor, and is arranged concentrically with the rotor; permanent magnets are arranged in the rotor, and are used for generating radial magnetic poles and axial magnetic poles; one part of the magnetic flux generated from each permanent magnet enters the corresponding radial stator through the corresponding radial magnetic pole and then forms a radial main magnetic flux with a radial armature winding crosslink; the other part of the magnetic flux generated from the permanent magnet enters the axial stator through the axial magnetic pole, and then forms an axial main magnetic flux with an axial armature winding crosslink; and the radial main magnetic flux is connected with the axial magnetic flux in parallel. The hybrid magnetic circuit low harmonic wave multi-stator flux-weakening speed extension permanent magnet synchronous motor, and the method thereof have the advantages of eliminating the magnetic leakage effect of the end part, improving the utilization rate of the motor material, reducing the weight of the motor, improving the power density, flexibly realizing magnetic enhancing operation and flux-weakening speed extension operation, and widening the economic operation range of the motor.

Description

technical field [0001] The invention relates to a permanent magnet synchronous motor, in particular to a mixed magnetic circuit low-harmonic multi-stator weak field speed-expanding permanent magnet synchronous motor and a method thereof. Background technique [0002] In recent years, with the improvement of high temperature resistance and price reduction of permanent magnet materials, permanent magnet motors have been more widely used in national defense, industrial and agricultural production, and daily life, and are moving towards high power, high performance and miniaturization. direction of development. At present, the power of permanent magnet motors ranges from a few milliwatts to several thousand kilowatts, and its application ranges from toy motors, industrial applications to large permanent magnet motors for ship traction, and has been widely used in various aspects of the national economy, daily life, military industry, and aerospace. widely used. [0003] The ex...

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Problems solved by technology

[0004] 1. The permanent magnet synchronous motor has a fixed permanent magnet magnetomotive force, and the main magnetic flux of the motor cannot be adjusted, resulting in a narrow constant power operating range and a wide range of speed regulation.

[0005] 2. In the existing built-in permanent magnet synchronous motor rotor structure, the permanent magnets of the rotor realize the "magnetism gathering effect" through various combinations, so the magnetic pole magnetic density of the rotor iron core is very high, so that there is a large leakage flux at the end, and the rotor The leakage flux is closed by the end of the motor rotor or the end cover. Since the total magnetic flux generated by the permanent magnet is constant, the existence of the leakage flux at the end not only makes the magnetic field distribution at the two ends of the motor uneven, but also reduces the effective flux of the motor. Utilization rate, thereby reducing the power density and torque density of the motor. In order to overcome the influence of the leakage flux at the end, the motor rotor often adopts an overhang structure in actual design, so that the axial length of the rotor core is greater than the axial length of the motor stator core. length, but this structure significantly increases the axial length of the motor, which in turn increases the amount of iron core material and manufacturing cost of the motor, and this structure does not essentially have the effect of suppressing the leakage flux at the end

[0007] 4. According to the different paths of the d-axis flux during field weakening, the existing permanent magnet synchronous motors with built-in rotor structure can be divided into two categories, one of which, when the field weakening control is performed, the d-axis generated by the armature winding The magnetic flux will pass through the permanent magnet of the motor, causing irreversible demagnetization of the permanent magnet. In the other category, when the field weakening control is performed, the d-axis magnetic flux generated by the armature winding is not closed by the permanent magnet, but the magnetic field generated by the d-axis current is forced More rotor flux closes through the ends of the motor and end caps, significantly increasing the leakage flux of the motor, and since the reluctance at the ends of the motor is usually much greater than the reluctance of the air gap, the required field weakening The d-axis current is high, which significantly increases the cost of the motor power inverter and the copper loss of the winding

[0008] 5. Existing permanent magnet synchronous motors usually have large armature back electromotive force harmonics and prominent cogging torque problems, which bring serious vibration and noise problems. At present, stator chute or rotor skew pole methods are usually used to improve back electromotive force. Electromotive force harmonics can weaken the cogging torque, but the processing technology of the stator chute and rotor slant pole is more complicated, which greatly increases the manufacturing cost, and will reduce the average electromagnetic torque of the motor to a certain extent, and reduce the torque density and power of the motor density

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