多相感应电机任意非正弦气隙磁密的磁动势分析与应用

多相感应电机转矩密度的提高依赖于非正弦气隙磁密行波的合理构建，由于传统的电流相位、幅值控制策略无 法给出期望的非正弦磁密行波，因此文章研究了控制多相感应电机定子相电流中基波和谐波幅值、相位、频率的大小来 构建期望的气隙磁密波形的方法、首先基于单根载流导体产生的气隙磁动势波形，推导了任意相数、不对称、包含任意 高次谐波电流波形激励的具有典型绕组结构的多相感应电机的磁动势分布表达式。根据以上磁动势分析结论，多相电 机可通过变电流相序变极。针对气隙磁密行波逼近方波波形的案例，根据所提出的磁动势分析方法分析和预测了理想 空载励磁电流的波形。将预测波形和方波供电下的励磁电流波形进行了比较，从FFT分析结果来看，仍需微调各次谐波 电压相位，从而实现各次电流相位完全一致。

MMF Analysis and Application for Arbitrary Air-Gap Flux Density in Multiphase Induction Machines

Torque density enhancement of multiphase induction machines ( MIMs ) defpends on the reasonable construction of non-sinusoidal air-gap flux density travelling waveform. Due to the defect of traditional strategy with amplitude and phase shifts control of phase currents which can't yield the desirable flux density travelling waveform, the method was found to concrol the phase shifts, amplitude , frequencies of phase currenls. MMF distribution expressions of MIMs with typical ,winding structure and arbitrary phase number based on the MMF waveform produced by one current- carrying conductor was derived. Phase currents were unsymmetrical and contain arbitrary higher harmonics. According to the conclusions from MMF analysis of MIMs above, Lhe pole pairs of MIMs could be controlled by phase shift between adjacent phases. In the case study of the air-gap flux density wave approaching square wave, the magnetizing current wave was analyzed and predicted in the light of the method of MMF analysis. It is found that phase shifts of voltage harmonics should be finely tuned, so thal the currenl harrmonics are in phase wilh each ocher in terms of FFT analyzed results from the comparison of predicted wave with the magnetizing current wave under square wave voltage power supply.