离散变频软启动转速检测的新方法及其应用  

Novel Speed Measuring Method of Discrete Variable Soft Starting and Its Application

作　　者：李冬辉[1] 马跃贤[1] 王波[1] 

机构地区：[1]天津大学

出　　处：《电气传动》2007年第11期14-17,共4页Electric Drive

摘　　要：三相异步电动机的离散变频软启动很好地解决了电机直接启动电流大和常规软启动器启动转矩不足的问题,是重载设备较好的启动方法。实现离散变频很重要的一点是根据电机的转速进行各频段的切换,这要求对电机的转速进行实时地监测。离散变频软启动作为一种新的软启动方法,现有的测速方法适应性较差。针对离散变频技术的调压调频特点,提出了基于电机失电残余电压的测速方法;该方法原理简单、计算量小、易于单片机编程实现,并具有较高的准确度。最后,利用该测速方法确定各离散频段切换时刻,进行电机的离散变频软启动仿真,从仿真结果来看各频段切换平稳,电机在各离散频段内保持良好的启动特性,证明了该方法应用可行性。Discrete variable frequency soft starting for three-phase asynchronous motors can restrain current impact during starting, such is capable of starting with high starting torque, and can avoid the deficiencies of conventional soft starters, as a better starting method for devices with high load. Switching of discrete frequency bands is very important to carry out discrete variable soft starting, so detecting the speed of motor from time to time is needed. As discrete variable frequency is a new soft starting method, adaptability of current speed measuring methods isn＇t better. Based on characteristics of discrete variable frequency soft starting, a novel speed measuring method using residual voltage after AC dump was proposed. This method with a simple theory and arithmetic, can be easily programmed in single chip, and is validated to have better veracity. At last, discrete variable frequency soft starting using this speed measuring method was simulated. The simulation results indicate that switching of discrete frequency bands is smooth, in every discrete frequency band mo- tor has better starting characteristics, the feasibility of this method is proved.

关 键 词：离散变频 软启动 MATLAB 失电残余电压 

分 类 号：TM925.12[电气工程—电力电子与电力传动]