基于SVG控制应用的数字滤波器实用设计

Practical Design of a Digital Filter Based on SVG Control Application

IIR型数字滤波器凭借其优良的衰减特性在利用软件处理信号的场合应用广泛。针对无功发生器(svg)控制保护装置应用程序开发过程中所使用的IIR数字滤波器,利用MATLAB中的FDAtool工具获得阶数和传递函数系数,并通过微调零极点位置获得较为理想的幅频曲线,并输出系数写入控制程序的函数中;分析采样周期对滤波器零极点位置的影响,在不同采样周期下,数字滤波器零极点位置发生改变,产生新的传递函数系数。经过在实际装置中的测试,获得了良好的滤波效果。

IIR digital filters find wide application in signal processing through software thanks to their excellent attenuation characteristics. With regards to IIR digital filters used in the development of application programs for the control protection device for Static Var Generator （ SVG）, FDAtool in Matlab is used to provide the order number and transfer function coefficient, a quite ideal amplitude-frequency curve is obtained through fine-tuning of the pole zero position in the tool, and the output coefficient is written into the function of the control program. This paper further analyzes the effect of sampling period upon pole zero position of the filter. For different sampling periods, the digital filter＇ s pole zero position differs from each other, thus generating a new transfer function coefficient. A good filtering effect is achieved as shown in the test on actual devices.