一种改善VVVF变频调速系统稳定性方法

针对异步电机运行在V/f控制方式下空载或者轻载时容易出现电流畸变振荡甚至系统不稳定现象,在功率控制原理基础上,提出了一种改善V/f控制交流传动系统稳定性的控制方法.通过深入分析系统不稳定时电机输入功率和电流之间的变换关系,在定子电压矢量定向坐标系中采用了一个频率补偿器的方法来动态调整频率,以达到抑制电流振荡的目的,保持系统的稳定性.该方法在通用的变频调速装置上仅仅由软件实现,不需要额外的硬件成本.仿真和试验结果表明,该控制方法能有效抑制电流和速度振荡,明显改善系统的稳定性.

Stability improvement for V/F controlled induction motor fed by PWM-VSI

Current distortion of V/F controlled motor and moreover the unstable phenomena may occur when the motor is in the no loaded or light loaded state. A novel approach of improving V/F controlled induction motor fed by PWM -VSI is proposed, which is based on power control. Deep analysis focuses on the change of inputting power and current when the motor is unstable. A kind of frequency compensator in the coordinate of stator voltage vector is adopted to adjust the given frequency dynamically for suppressing the oscillations and keeping the stability. The proposed method is easy to implement by software without adding extra hardware in the general variable speed devices. Simulation and experiment results demonstrate that it can effectively suppress the oscillations of current and rotor speed and improve the stability of system.