一种能反映电机磁场状态的实验系统

A Design of Experimental System to Reflect Conditions of Motor Magnetic Field

为提高"电机学"及相关课程的教学质量,提出了将电机运行时的气隙磁场状态图引入教学的方法,制成一种实验演示系统。该系统将微处理器产生的正弦脉宽调制信号经功放电路馈入电机绕组,供电机运行。然后将采样电流的基波幅值、基波电流间相差、电流频率等信号通过串口送至计算机,依据这些信号,综合电机的定转子磁路结构和绕组分布规律,计算出气隙磁势在不同时间沿气隙分布状态,进而计算出磁势幅值在空间运行轨迹,并在界面上绘制。通过键盘可控制电流的频率、相序、相差等来改变电机的运行状态。

In order to improve the teaching quality in electric machinery and related courses,a method that introduces the distribution of air gap magnetic motive force（ MMF） when motor runs into teaching is purposed,and a teaching experiment demonstration system is developed. In the system,SPWM signals are generated by the MCU,amplified by the power amplifier circuit and finally injected into the motor windings for the motor operation. Then the signals of the magnitude,phase difference and frequency of fundamental sampling current are sent to the computer through a serial port. Considering the magnetic circuits of the stator and rotor and the distribution of windings,the computer can calculate the distribution of air gap MMF in different time,thus can calculate the operating trace of the magnitude of MMF and draw the trace on the interface. The frequency,phase sequence and phase difference can be controlled through the keyboard to change the operating state of the motor. The innovation of the system is that it displays the state of the fundamental air gap MMF on the interface and can capture the state at any time for the analysis in class by pressing the ＂pause＂button.