城市轨道交通中直线感应电机的非线性设计

Nonlinear design of linear induction motor for urban rail transit

本文提出用于城市轨道交通系统的直线感应电机(LIM)的非线性设计方法。该方法采用二维时步有限元法和外部驱动电路联立求解,考虑LIM的磁轭和背铁材料中的磁饱和现象和运动速度对端部效应的影响,直接计算出LIM在起动和正常工况运行时的电流、电压、磁密、推力、效率等参数。与传统的线性设计方法相比,非线性设计得到的电流与推力关系更为准确,为正确选择电机的冷却容量和驱动变频器的伏安容量提供了可靠的依据。计算实例验证了新方法的有效性。

A nonlinear design approach of linear induction motor （LIM） for urban rail transit is presented. The method is based on coupling of two-dimensional time-step finite element method and exterior drive circuit. Magnetic saturation of yoke and back iron, and edge effect caused by velocity are considered sufficiently. Current, voltage, magnetic flux density, thrust and efficiency can be calculated directly. By comparing with linear design method, the current and thrust calculated by nonlinear method are more accurate. It provides reliable basis on selection of cooling capability of motors as well as power capacity of variable frequency drives. A calculation example is presented to demonstrate the effectiveness of the proposed method.