异步电动机功率因数自动控制实验

为了提高异步电动机的节能效果，按异步电动机简化等效电路图推导出功率因数与转差角频率的关系，设计了新型的带功率因数自动控制的异步电动机变频调速系统。为提高控制性能，提出一种解决非线性控制的方法。解决了功率因数与转差角频率及转矩之间的非线性关系的线性化问题。为了避免负载变化造成最佳功率因数点的移动，增加了抗负载扰动环节，保证系统运行于最佳功率因数点。实验结果表明系统在轻载和欠载时有明显的节能效果．在整个调速范围内运行性能良好。

Experiments on automatic control system for power factor of asynchronous motor

In order to improve the effect of saving energy,the system is designed.On the basis of the simplified and equivalent circuit of asynchronous motor,the relationship between the power factor(PF)and the augular frequency of speed drop is derived and a new type of frequency conversion and speed adjustment system of PF auto-control is constructed.A method is put forward to solve unlinear control,then transform unlinear character about PF,augular frequency of speed drop and torque into linear character.An anti-interference circuit is also built up in the system to avoid the shift of the optimal PF point caused by the change of load and the reliable running of the control system is assured.The experiment result shows it has good self-adaptivity in the whole scope of speed adjustment and economization on energy while it runs well in the whole speed adjustment range.