Method for calculating load electromagnetic excitation force waves of built-in permanent magnet synchronous motor

Abstract

The invention provides a method for calculating load electromagnetic excitation force waves of a built-in permanent magnet synchronous motor, and the method comprises the steps: carrying out the calculation of air gap flux density under a no-load condition through a finite element to obtain the relation between magnetomotive force and magnetic conductance under the no-load condition; simulating toobtain a d-axis magnetic conductance model of an armature magnetic field by utilizing a method of freezing magnetic conductivity, accurately calculating a magnetomotive force and magnetic conductancerelationship generated by independent action of a winding under a load condition according to the model, and solving an air gap flux density generated by the winding; superposing the air gap flux densities generated by the permanent magnet and the armature winding by using a superposition principle to obtain a built-in load air gap flux density expression; according to a Maxwell tensor method, putting magnetomotive force and air gap magnetic conductance component results into an electromagnetic force density expression to accurately obtain force wave amplitudes under different frequencies anddifferent orders.

Description

technical field [0001] The disclosure belongs to the technical field of permanent magnet synchronous motors, and in particular relates to a calculation method for electromagnetic excitation force waves of loads of built-in permanent magnet synchronous motors. Background technique [0002] The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. [0003] Noise pollution, air pollution, water pollution and solid waste pollution are called the four major pollutions in the world today. Noise pollution is a kind of environmental pollution, which has become a major hazard to human beings. Working in a noisy environment for a long time will cause a series of physiological and pathological changes in the human nervous system, cardiovascular system, endocrine system and digestive system. In recent years, permanent magnet synchronous motors have shown broad application prospects in various fiel...

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Problems solved by technology

The magnetomotive force-permeance method is based on the principle that the air gap magnetic density is equal to the magnetomotive force multiplied by the permeance, the frequency, order and phase of the electromagnetic excitation force wave can be given, and the corresponding order electromagnetic force wave generation term can be derived. This method has limitations. It cannot obtain the accurate value of the electromagnetic force wave. It can only perform stereotyped analysis but not quantitative analysis. The scope of application is limited. Although the magnetic field analysis method can easily calculate the air-gap magnetic field and vibration force wave, it is difficult to consider the core When the saturation and the complex shape of the alveolar, the calculation cycle will be lengthened and the calculation accuracy will be reduced, and this method is difficult, and it is not easy to calculate quickly and accurately; while the finite element method can consider the influence of various factors such as saturation, and can be performed more accurately Calculation of the air gap magnetic field and electromagnetic force density, but cannot effectively analyze the source of the exciting force wave, and cannot deduce the source term of the specific exciting force wave. The finite element method can only be quantitatively analyzed, not qualitatively

[0005] The above three methods of calculating electromagnetic force have their own advantages and disadvantages, and neither can accurately determine the complete expression of each electromagnetic force wave including amplitude, rotational speed, frequency and phase, nor can it accurately evaluate the influence of a single electromagnetic force wave on vibration , and cannot accurately evaluate the overall effect of each electromagnetic force wave on vibration, which is not conducive to the analysis and weakening of electromagnetic vibration

[0006] For the built-in permanent magnet motor, due to the saturation and air gap inside the rotor, the internal structure of the rotor will have an impact on the electromagnetic field. At the same time, the influence is different under different current amplitudes and different power angles. The load magnetic field of permanent magnet motors brings certain difficulties. In the existing finite element method, the accurate value of the load air-gap magnetic density can be obtained, but this method cannot deduce the causes of various air-gap magnetic density, and at the same time cannot Can effectively analyze the specific source of electromagnetic excitation force wave

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