梁艳萍 李伟 王泽宇 高莲莲

Abstract：A semi-analytical method for calculating the eddy current losses in rotor of large high speed induction motors was proposed by combining analytical method and two-dimensional eddy-current finite element analysis. The two-dimensional eddy-current finite element analysis was used to calculate the magnetic flux density on the rotor surface， therewith an analytical formula of the semi-analytical was derived in detail on the basis of Maxwell equations. Taking a megawatt class high speed induction motor as an example， eddy current losses in rotor are calculated by the semi-analytical method .The calculation result was verified by the two-dimensional transient finite element analysis. In addition， the semi-analytical method was adopted to study the influence of rotor material and rotor structure on eddy current losses in rotor. The results show that rotor material with high relative permeability and low conductivity can reduce rotor eddy current losses， and the eddy current losses in rotor can still be reduced by the conductive end rings.

Keywords：high speed induction motor; eddy current losses in rotor; semi-analytical method; rotor material; rotor structure

0 引 言

高速感應电机因其可与高速负载直接相连，省去了常规电机所需的机械增速装置，减小系统的噪音和体积、降低了运行和维护成本、提高了系统的可靠性，因而主要被广泛应用汽车制造、高速主轴系统、天然气输送高速离心压缩机以及石油等工业领域[1-4]。

目前，由于工业水平发展和制造工艺水平的提高，国外对大型高速感应电机的研究已经取得了一些成就。为了开发新一代节能、高速中压传动系统，西屋公司研制一台额定功率为1 MW、同步转速为15 000 r/min的高速感应电机[5]。2002年ABB公司研制了一台应用在天然气输送高速压缩机上、额定功率为15 MW的实心转子高速感应电机[6]。德国达姆施特大学设计分析了一台同步转速为24 000 r/min的高速感应电机，并研究了转子轴向开槽对转子涡流损耗的影响[7-8]。国内对高速感应电机的研究大多停留在中小型或较低的转速范围内，对大型高速感应电机研究较少，与国外相比还有较大差距[9]。

大型高速感应电机由于其转子半径较大、转子转速较高，转子所受的机械应力较大，因此，必须对大型高速感应电机的转子结构进行特殊设计。为了满足大型高速感应电机转子的机械要求，转子通常选用光滑实心转子结构，但定子绕组电流频率较高，高次谐波在光滑实心转子内引起转子涡流损耗较大，进而引发转子温升较高、转轴机械强度下降等问题。对大型高速感应电机，光滑实心转子内较高的涡流损耗与转子机械强度的要求俨然成为限制其发展的主要矛盾。……