Research of the Hish Efficiency Induction Motor with Built-in Magnet

本研究以开发一种新型高性能感应电机为目标，研究了一种独特的内置磁体的笼型转子自由旋转感应电机。内置式磁感应电机具有大扭矩、高效率、功率因数可变的特点。参考其磁路模型，推导出了目前尚不清楚的内置式磁感应电机的电气等效电路。针对内置式磁感应电机启动力矩小、高速时需要弱磁控制的问题，研制了一种采用双笼型转子的内置式磁感应电机。新的感应电机可以在额定扭矩的60%以下启动。对内置式双笼转子磁感应电机在不同频率下的效率特性进行了测试。与预期相反，磁铁式双笼转子感应电机在低频、低输出区域的效率低于市售电机，但在高频、高负载区域的效率远高于其他类型的感应电机。这一弱点可以通过改进其转子的导体结构来克服。对于内置式磁感应电机来说，由于其结构和运动非常复杂，磁场分析似乎是不可能的。在这项研究中，我们通过设计分析方法首次成功地对其进行了磁场分析。

In this research, aiming at developing a new induction motor with high performance, we investigated a unique induction motor with built-in magnet that rotates freely in its caged rotor. The built-in magnet induction motor had interest characteristics of high torque, high efficiency and variable power factor. Referring to its magnetic circuit model, electric equivalent circuit that was not clear until now was derived for the built-in magnet induction motor. The interest characteristics of a built-in magnet motor could be analyzed by the equivalent circuit.Since this built-in magnet induction motor has a problems that starting torque is small and that field weakening control is necessary in high-speed area, a built-in magnet induction motor that adopted a double caged rotor was developed to solve this problem. The new induction motor was possible to start for less than 60% of a rating torque. Efficiency characteristic was measured for built-in magnet induction motor with double caged rotor in various frequencies. Against expectation, the efficiency of magnet type induction motor with double caged rotor was lower than that of marketing machine in low frequency, and low output area, but in high frequency and high load area, the efficiency became much higher than that of other induction motor. This weak point can be overcome by improving its conductor structure of rotor.The magnetic field analysis seemed impossible for the built-in magnet induction motor, because its structure and motion were very complicated. In this research we succeeded for the first time in its magnetic field analysis by devising analytical method.