基于电流环相位裕度和补偿特性的静止无功发生器低通滤波器与调节器参数设计方法

Design of Low Pass Filter and Regulator Parameters in Static Var Generator Based on Current Loop Phase Margin and Compensation Characteristics

在直接电流控制方法下,提出了基于电流环稳定性和无功补偿特性的静止无功发生器(SVG)低通滤波器与调节器参数的设计方法。通过建立SVG系统简化模型,利用传递函数和基于Bode图的频域分析方法定性分析了L型、LC型和LCL型低通滤波器的参数对系统稳定性的影响,在此基础上忽略对稳定性影响小的参数,简化包含系统各参数的相位裕度表达式,给出三种低通滤波器参数、调节器参数和截止频率(补偿特性)之间的关系,最终提出了全局参数设计方法,该方法考虑了相位裕度、调节器参数、截止频率和低通滤波器的参数。该方法明确了各参数与相位裕度之间的关系,避免了传统低通滤波器设计方法中不能与调节器参数和相位裕度相结合的问题,完善了SVG参数设计方法。实验验证了本文所得出的稳定性分析的结论和参数设计方法的正确性。

Based on the current loop＇s stability and the reactive power compensation characteristics under direct current control, this paper proposes a low pass filter and regulator parameter design method for the static var generator（SVG）. After the simplified model of the SVG has been built, the influences of parameters in L-type filters, LC-type filters, and LCL-type filters on the system stability are investigated using the transfer function the and frequency domain analyzing method with Bode diagram. Based on those results, the parameters which have a small influence on the stability are ignored to get a simplified phase margin equation which includes the system parameters. The relationships of filter parameters, regulator parameters and cut-off frequency（compensation characteristics） in SVG with three different types of low-pass filters are presented. Finally, the parameters design method is proposed in which the phase margin, the regulator parameter, the cut-off frequency, and the low-pass filter parameters are considered. With this method, the relationship between the parameters of the SVG and the phase margin is straightforward. The presented method improves the traditional low-pass filter design method which cannot combine the regulator parameters with the phase margin. The stability analysis conclusion and the validity of the parameters design method are verified by the experiment.