A Prediction Method of Harmonic Current of Permanent Magnet Motor

Abstract

The invention discloses a method for predicting the harmonic current of a permanent magnet motor. Establish a motor magnetic field distribution model considering the saturation effect of ferromagnetic materials. The input of the motor magnetic field distribution model is the harmonic current of the permanent magnet motor, and the output is the terminal voltage of the permanent magnet motor; establish the inverter output based on the space vector modulation of the modulation function Double Fourier series model of voltage harmonics, input the modulation depth, and obtain the output voltage of the inverter; establish a matching degree between the terminal voltage of the permanent magnet motor and the output voltage of the inverter as the optimization target, and propose a harmonic current The matching method, that is, through the optimization algorithm to globally optimize the harmonic currents of each order of the motor magnetic field distribution model, and obtain the amplitude and phase of the harmonic currents of each order, and then obtain the harmonic current. The time for processing the harmonic current of the invention is shorter than that of the finite element processing method, and the output result is consistent and accurate with the result calculated by the finite element.

Description

technical field [0001] The invention relates to a parameter detection method of a permanent magnet motor in the field of motor electromagnetic performance analysis, in particular to a prediction method of a harmonic current of a permanent magnet motor. Background technique [0002] Accurate and rapid analysis of the electromagnetic performance of motors is the basis for the design of high-performance permanent magnet motors. High-performance permanent magnet motors are generally driven by voltage source inverters based on pulse width modulation, but the inherent switching process of the inverter will generate rich magnetic field time harmonics in the motor, and the resulting harmonic current will have a negative impact on the motor. Performance brings a series of damages, such as increase in torque ripple, electromagnetic loss, noise, and vibration. [0003] At present, the finite element method and analytical method are generally used to analyze the harmonic current of the...

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Problems solved by technology

Based on the finite element method, a co-simulation model including the motor and the inverter can be established to analyze the harmonic current of the motor. The calculation accuracy is high and the application range is wide, but the calculation speed is slow and usually takes dozens of hours.

Analytical method (typically such as paper W.Liang, J.Wang and W.Fang, "Analytical Modeling of Sideband Current Harmonic Components in Induction Machine Drive With Voltage Source Inverter by an SVM Technique," inIEEE Transactions on Power Electronics, vol.28, no. 11, pp.5372-5379, Nov.2013.) Based on a specific modulation strategy (such as space vector modulation), the harmonic current expression of a certain type of specific motor is directly derived, and the calculation speed is fast but the scope of application is narrow

Moreover, the derivation of the analytical method is based on a lumped parameter model of a certain type of specific motor, and it is difficult to accurately consider the influence of the saturation effect of the ferromagnetic material inside the motor on the harmonic current calculation.

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