In some control strategies of the direct-rive permanent magnet generator(DDPMG),the mathematics model is excessively simplified and some complex nonlinear characteristics,such as core saturation and cross-saturation,are generally neglected.To solve this problem,this paper utilizes the frozen element permeability method to compute the armature self-and mutual-inductance,permanent magnet d-and q-axis flux varying with d-axis and q-axis current,then an improved model is presented in which the core saturation and cross-saturation between d-axis and q-axis are considered effectively.Based on this model,the method for computing the performance of the generators is also proposed.Taking a 1.5-MW DDPMG as an example,the time-stepping finite element method(T-S FEM) is adopted to analyze the performance with no-load and loaded conditions,the results show a good agreement with the ones obtained by the improved model.Compared with the simplified model,it is demonstrated that the presented model has the high efficiency and reliability and can provide a good reference for optimization design of DDPMG and other PM motors.
快速、准确地计算电压暂降过程中定子绕组的冲击电流,对于电机安全稳定运行具有实际意义。基于空间向量法,提出一种计算异步电机暂降过程中定子电流的新方法,利用电机空间矢量模型阶数较低的特点,减少状态变量个数,有利于电动机暂降过程中复杂瞬态过程计算的简化,电机轻载时直接推导出解析公式,重载时可以减少状态方程个数,以便利用数值算法求解。搭建5.5 k W异步电机的实验测试平台,对比电压暂降过程中定子电流计算与实测波形,验证文中所提出方法的正确性。
