交流调谐滤波器失谐度检测方法的研究

失谐度的在线检测是评估调谐滤波器运行状态和实现滤波器自动调谐的关键,但是,按照失谐度的定义难以实现失谐度的在线直接测量。通过对滤波器失谐特性的分析,推导出失谐度与滤波器谐波阻抗角的正切值成正比关系,并由此提出了一种失谐度的间接测量方法。对母线电压和滤波器电流进行同步采样,利用离散傅立叶变换求取滤波器的谐波阻抗角,进而计算出失谐度。建立了基于LabVIEW的失谐度在线检测系统,实验结果表明该方法的测量精度满足自动调谐控制系统的要求。

Research on the Measurement of Detuning in AC Tuned Filter

On-line detection of filter detuning is the key to evaluate the filter operation status and to tune the filter automatically, but it is difficulty to detect the detuning directly according to its definition. By analyzing the characteristics of filter detuning, the relation that detuning is proportional to the tangent of h-order harmonic impedance angle of the filter was deduced, and hence an indirect measurement of detuning is presented. The harmonic impedance angle is obtained by analyzing the sampled bus voltage and filter current with the help of discrete Fourier transform, then the detuning is calculated. A detuning measuring system based on LabVIEW was developed, and the experimental result shows that the proposed detuning measurement satisfies the requirement of auto-tuning control system.