Method and device for calculating torque ripple coefficient of surface-mounted permanent magnet synchronous motor

Abstract

The invention discloses a method and device for calculating a torque ripple coefficient of a surface-mounted permanent magnet synchronous motor. The method comprises the following steps of acquiring athree-phase current waveform and a back electromotive force waveform of the surface-mounted permanent magnet synchronous motor; carrying out Fourier decomposition on the three-phase current waveform,calculating the main order and the corresponding amplitude of three-phase current harmonics, and then obtaining the phase corresponding to each order of current harmonics; carrying out Fourier decomposition on the back electromotive force waveform, and calculating the main order of the flux linkage harmonic and the amplitude of each harmonic; substituting the main order and the corresponding amplitude of the three-phase current harmonic, the phase corresponding to each order of current harmonics, the main order of a flux linkage harmonic wave and the amplitude of each harmonic wave into a torque analysis model to obtain a torque value; and selecting a maximum torque value and a minimum torque value in the three phases of the surface-mounted permanent magnet synchronous motor, and calculating to obtain a torque ripple coefficient. The method is helpful for monitoring the torque ripple degree of the permanent magnet synchronous motor under the actual working condition and carrying outfault prediction according to the change of the torque ripple degree.

Description

technical field [0001] The invention relates to the technical field of motors, in particular to a method and device for calculating the torque fluctuation coefficient of a surface-mounted permanent magnet synchronous motor. Background technique [0002] Permanent magnet synchronous motor has the advantages of high power-to-mass ratio, energy utilization rate and good servo performance, and is widely used in machinery manufacturing, robot control, aerospace and other fields. In practical applications, affected by factors such as air gap magnetic field harmonics, magnetic field harmonics, stator current time harmonics, motor magnetic circuit saturation, and manufacturing errors, the output torque of permanent magnet synchronous motors will inevitably fluctuate. Torque fluctuations will cause speed fluctuations, causing the motor to vibrate and make noise. The increase of torque fluctuation will aggravate the vibration and noise of the motor, which will lead to aggravated vibr...

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Problems solved by technology

[0007] The purpose of the embodiment of the present invention is to provide a surface-mounted permanent magnet synchronous motor torque fluctuation coefficient calculation method and device to solve the problem of inaccurate calculation of the existing fluctuation coefficient

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