Firstly , the experimental phase current and input power data obtained from load test are employed to estimate the parameters in ii rated condition . then , the phase current and input power data in locked rotor condition are used to track the variation of the parameters of the secondary coil with slip frequency . the classical method and the direct modification method are also used to estimate the parameters of the induction machine in comparison with this technique 首先利用了负载试验的定子电流和输入功率数据来识别额定工况下的电机参数，然后又使用了堵转时的定子电流、输入功率数据来识别电机二次绕组参数随转差频率的变化，并与传统参数测试方法和直接修正参数法进行了比较。
To great extent the performance of field oriented control depends on the precise measurements of motor parameters . the initial values of motor parameters can be measured by the no - load and locked rotor tests . but some parameters will vary with the temperature rise and magnetic saturation , and they must be real time identified 矢量控制系统的性能很大程度上依赖于电机参数的准确测量，利用空载、堵转实验只能得到电机定转子参数的初值，而电机的一些参数会随着温升和磁路饱和发生变化，需进行在线实时辨识。
Linear induction motor is an important kind of machines which have some merits such as simple structure , low cost , durability , convenience for maintenance etc . the subject of this thesis is to study a big circular ring linear induction motor , and the major works in this thesis are summarized as follows : ( 1 ) considering the effects of the finite length of primary core , one - dimension analytical solution for the air gap field is cited in this paper . based on it , the single layer winding magnetic field is studied . considering whole - pitched and short - pitched winding configuration with odd poles and half - fulled slots in both ends , the double - layer winding magnetic field is analyzed , respectively 本文对大圆环直线感应电机进行了深入细致研究，内容包括： ( 1 )本文采用有限长行波面电流作用于有限长铁芯上的模型，引用了气隙磁场一维解，研究了单层绕组磁场，奇数极半填槽双层绕组在采用整距和短距时磁场的分析、比较，简单介绍了二维解； ( 2 )用有限元软件ansoft对大圆环直线感应电机空载气隙磁场进行了静态分析，并分析了结果； ( 3 )用软件进行了额定电压下的瞬态分析，得到了转矩，位移，转速随时间变化曲线图，利用单极性霍尔元件测定转速并与软件计算结果进行了比较，采用等效电路法计算了堵转时的最大电磁力并做实验进行了验证，由实验测得了三相电流波形，并与计算结果进行了比较，对其不对称性进行了定性分析。
