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Electromagnetic Noise Investigation Of Induction Machine For Electric Vehicle Drives

Posted on:2008-11-03Degree:DoctorType:Dissertation
Country:ChinaCandidate:Y DaiFull Text:PDF
GTID:1102360245997362Subject:Motor and electrical appliances
Abstract/Summary:PDF Full Text Request
Low noise is come to be an important performance target of electric vehicle (EV) along with the attention of the noise pollution. Drive motor is the important part of the EV driving system. Relative to the drive motor for industry, drive motor for EV has the design characteristics of big current density and high flux density, wide speed operating range, complex operation conditions and variable frequency variable speed. These characteristics make big possibility of load electromagnetic noise and increase the reduction difficulty. Induction motor is the main type for the EV drives. The electromagnetic force waves acting on the stator and the inherent modes of the motor are the two key factors that decide the electromagnetic noise of the induction motor. Researches are working hard on the two aspects to analyze the electromagnetic noise of the induction motor for EV drives.For the big change of load and speed of the induction motor for EV drives, the harmonic air gap flux densities induced by stator and rotor at deferent speeds and loads are analyzed by FEM. The variation rules of harmonic air gap flux densities with speed and load are analyzed. It is investigated how the design characteristics influence the magnitudes, orders and frequencies of the electromagnetic force waves. The base of optimizing the electromagnetic noise for the induction motor is built.This article not only calculates the nature frequency of the stator stacks and the stator assembly by using the single ring and double ring methods, but also predicts the speeds at which the resonances happen. The influences of stator teeth, windings, shell, and end covers and rotor on the inherent modes of induction motor are analyzed by FEM.Whether electromagnetic resonances happen or not and the resonance speeds are predicted by the electromagnetic forces and inherent modes analysis results. The design method to reduce electromagnetic noise is investigated from electromagnetic force and inherent mode of the motor. It is investigated that the best slot combination for the electromagnetic noise reduction. Low order electromagnetic force waves inducing loud noises are eliminated for the 40kW induction motor. By increasing current densities reducing flux densities and increasing the thickness of shell and end covers, the electromagnetic noise is optimized for the 30kW induction motor.The electromagnetic noise of the induction motor for EV drives is investigated by experiment. The main source of the motor noise is judged by the method of cutting down supply suddenly. The Spectra of no-load noises at deferent speeds are analyzed. The electromagnetic force wave's characteristics are investigated by the experiments. The inherent modes are tested by the experiments. The experiment results validated the analysis of electromagnetic force waves and natural frequencies computation results.
Keywords/Search Tags:electromagnetic noise, induction motor, electric vehicles, inherent mode
PDF Full Text Request
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