摘要
LCI(Load Commutated Inverter)驱动的同步电机调速系统在大容量的调速场合仍有着广泛的应用,而谐波电流引起的脉动转矩是这类系统中不可忽视的一个问题。在计算脉动转矩时,传统的时域方法存在着计算速度慢,收敛困难,不易得到转矩的频谱分布等缺点。本文提出一种计算LCI驱动同步电机调速系统脉动转矩的工程方法,从频域的角度出发,应用开关函数调制理论建立了晶闸管三相桥及整个六脉波LCI驱动同步电机调速系统的数学模型。基于该模型可以求得系统中各次电流谐波的精确值,进而可以求出电磁转矩及其频谱分布。针对一般的调速系统,对上述模型进行了简化,保证了系统精度,并提高了运算速度。计算结果证明该方法与传统时域方法相比,具有很高的精度,并可以大大提高计算速度。
load commutated inverter （LCI） fed synchronous motor drive is still widely used today in large scale variable speed applications sueh as fans and pumps. However magnetic torque ripples caused by current harmonics is a serious problem in such systems. The traditional time domain method can compute the torque harmonics but costs a long time and it＇s hard to get the torque spectrum. This paper builds the mathematical model of 6-pulse LCI fed synchronous motor drive system in frequeney domain using the modulation theory. Based on the model, the current and torque ripples can be easily computed. According to the feature of normal LCI drive systems, the model is further simplified, which will largely shorten the computing time but without causing an evident error. Computing results show that the proposed method has a good computing accuracy and a much faster computing speed than the traditional time domain method.
出处
《电工电能新技术》
CSCD
北大核心
2009年第3期18-22,共5页
Advanced Technology of Electrical Engineering and Energy
关键词
LCI
转矩脉动
谐波电流
调制函数法
load commuted inverter
current harmonics
torque ripples
modulation theory
