一种改进的异步电机VVVF系统稳定性改善方法  

Droop Control Based Stabilizing Method for VVVF PWM Inverter Fed Induction Drive System

作　　者：孙东[1] 杨淑英[1] 曹朋朋[1] 郭磊磊[1] 

机构地区：[1]合肥工业大学电气与自动化工程学院,安徽合肥230009

出　　处：《电力电子技术》2016年第8期48-51,共4页Power Electronics

摘　　要：通用脉宽调制(PWM)变频器驱动异步电机工作在VVVF模式下时,系统较易遭受持续振荡问题,该问题在轻载和低频条件下尤为突出。为抑制振荡,提升这一简单变频调速方案的工程实用性,这里在分析系统振荡内在机理的基础上,提出了一种增强型VVVF控制策略。该策略依据定子电流的振荡分量,对通用逆变器输出电压的幅值和频率进行下垂调节,其对应定子电流振荡分量的提取是通过定子电压定向坐标系下双低通滤波器的设计实现的。在下垂算法设计中,有功电流振荡分量用于电压频率下垂控制,而无功电流振荡分量则用于电压幅值下垂控制。该策略在维持VVVF模式参数鲁棒性和简单性的同时,如同小信号分析所表明的那样,较好地改善了系统的稳定性和运行性能。方案的有效性通过仿真和实验得到了证明。Sustained oscillations are often experienced when induction motor is fed with general-purpose pulse width modulation （PWM） inverter operated in constant VVVF mode, especially under light loaded and low frequency conditi- ons.To stabilize the annoying oscillations and facilitate engineering practices of the simple control mode, an enhanced VVVF control strategy is proposed following the analysis of the inherent mechanism of the phenomena.In the proposed control strategy,the frequency and amplitude of the output voltages of general-purpose inverter are dynamically dropped with respect to the oscillation components in the stator currents.To extract the fight oscillation components, dual low pass filters with different cut off frequencies are adopted to filter the active and reactive currents obtained by coordinate transformation on the sensed stator currents.The dynamic oscillation component out of the active current is used to drop the frequency and that out of the reactive currents is used to drop the amplitude of the output voh- ages.By the proposed stabilizing method ,the operating stability and drive system performances are improved as shown by small signal analysis, while the merits of parameter robustness and simplicity of VVVF mode are still retained.The effectiveness of the proposed stabilizing method are demonstrated and validated by experiments.

关 键 词：异步电机 下垂控制 有功电流 无功电流 

分 类 号：TM315[电气工程—电机]