电流源供电模式的直流电动机失磁状态分析

Analysis of DC Motor in the State of Lost Field in Current Source Supplied Mode

简述了他励式直流电动机在失磁状态下会出现的"转速飞逸"和严重过电流问题;分析了电流源模式的电力电子变换器驱动他励式直流电动机在失磁状态下的工作特性。得出了电力电子变换器的速度闭环即使在轻载甚至空载状态下仍可以限制他励式直流电动机的转速不会出现"转速飞逸"现象,并最终稳定于给定转速;电力电子变换器的电流源特性具有最大限幅值,限制了他励式直流电动机在失磁状态下的最大电流值;分析了在最不利的情况下,失磁过电流对系统可靠性的影响。通过实验结果验证了本文提出的结论。

In this paper,the“rotating speed”and the serious current problem of the separately excited DC motor in the state of lost field are briefly described,and the working characteristics of the electric converter driven by the current source mode in the lost field are analyzed.The speed of separately excited DC motor by power electronic converter’s speed closed loop is limited,even under light load or no-load condition which can still limit his wound type of separately excited DC motor speed,the rotating speed will be eventually stable;The current source characteristic of power electronic converters has the maximum value,which limits the maximum current value of the separately excited DC motor in the state of lost field.The influence of the lost field over current on the reliability of the system in the worst condition is analyzed.The conclusion of this paper is finally verified experimentally.