Fundamental Research on Design Consideration of High Speed Induction Motor and its Speed Sensorless Vector Control at Maximum Efficiency for Electric Vehicles

在本研究中，我们的工作目的之一是分析和找出转子棒间的交叉电阻、偏斜因子和集肤效应对变频调速电动汽车驱动的高速笼型异步电动机转子槽设计的影响。基于三相异步电动机的理论和仿真结果，在考虑转子集皮效应和空间谐波的基础上，讨论了三相异步电动机在不同交叉路径电阻值和梯形转子棒的偏斜因素下的驱动性能。得到了等效转子电阻和漏抗随基频不同值的交路电阻、空间谐波和偏斜因数的变化规律。最后，讨论了适用于电动汽车大转速范围的变频高速笼型异步电动机的梯形转子槽形状，以获得良好的效率和转矩性能。本研究的另一个目的是提出在电动汽车大速度范围内高效运行的无速度传感器直接磁场定向控制异步电动机的高效转子磁链控制。该系统采用自适应转子磁链观测器实现。实验和仿真结果都证明了这一点。所提出的系统在稳态下的效率远远优于具有恒定额定转子磁链的系统，并且其电机速度响应在瞬态下没有退化。最后，明确了定子电压偏置对无传感器直接磁场定向异步电动机驱动的低速特性有显著影响。此外，还提出了一种补偿定子电压偏置的方法。仿真和实验验证了该方法的有效性。

In this research, one of the purpose of our works is to analyze and find out the effects of crosspath resistance between rotor bars, skew factor and skin effects on the rotor slot design of inverter-fed high speed cage induction motor driving for wide speed range of electric vehcles. The performance of the induction motor drives for various values of crosspath resistance, and skew factor with the trapezoidal rotor bar have been discussed on the basis of theoretical and simulationresults of a three phase induction motor taking into account the skin effect of the rotor and the space harmonics. It has been obtained that the equivalent rotor resistance and leakage reactance change with crosspath resistance, the space harmonics, and the skew factor for various values of the fundamental supply frequency. And finally, we discussed the rotor slot-shape of the trapezoidal rotor slot for good efficiency and torque performance of the inverter-fed high speed cage induction motor for wide speed range of electric vehcles.The other purpose of this research is to suggest the high efficiency rotor flux control of the speed sensor less direct-field-oriented controlled induction motor operating at high efficiency for wide speed range of electric vehcles. The proposed system was achieved by using an adaptive rotor flux observer. This was shown by experimental and simulation results. The proposed system was far superior to one with a constant rated rotor flux with regard to efficiency in the steady state, and it's motor speed response showed no degradation in the transient state.Finally, It has been made clear that the stator voltage offset influences the low speed characteristics of the sensorless direct-field- oriented induction motor drives significantly. Furthermore, a method of compensating the stator voltage offset has been proposed. The validity of the proposed method has been verified by the simulation and experiment.