拓宽调速范围的微机PWM变频传动系统

本文对单CPU结构的PWM变频调速系统做了一些探讨。为解决系统中存在的微机计算速度偏低和硬件复杂性问题,较好地处理软件和硬件的配合问题,本文提出了在较少的硬件结构基础上,通过在线设置辅助数据表,实现计算和存贮相结合的PWM方式:在设计中,利用了微机键盘和显示器实现系统管理。为解决电动机低速运行时机械特性变软这一问题,本文提据电动机定子电压和频率的协调控制原则,实现以电动机基波电流和功率因数为反馈信号的协调控制。实验结果表明,所设计的变频调速系统具有较宽的调频范围、较高的电压及频率分辨率,低速带负载能力大为改善,操作灵活方便。

The Microcomputer Controlled PWM Drive System with Wide Running Range

Some explorations for the pulse width modulation(PWM) inverterdrive system with single central process unit(CPU) structure aremade. The authors put forward the PWM scheme with less hardwarethrough setting the on-line aided data table to implement the combination of computation and storage, thus solve the problemsof low processing speed of microcomputer and complexity of hardwarelow processing speed of microcomputer and comlexity of hardwarestructure, and obtain better coordination between software andhardware. The key board and display are used to carry out systemmanagement in designing. In order to overcome the AC motor'smechanical property softening when it runs at low speed, based onthe control principles of coordination between stator voltage andfrequency, coordinated control is carried out by taking base currentand power factor of the motor as feedback signal. The results ofexperiments show that the inverter drive system has the merits ofwider ranning range, higher resolution of voltage andfrequency, driving load capability at low speed and convenience inoperating.