三电平结构SVG输出电流谐波分析及滤波器设计

Harmonic analysis and filter design for output current of three-level SVG

研究三电平静止无功发生器主电路结构与调制方法。对三电平SVG输出电流谐波与纹波电流进行分析并利用双重傅里叶变换推导出三电平SVG输出电流公式并计算输出电流纹波。通过对输出电流纹波的计算,可以知道在达到相同电流纹波要求的情况下,三电平SVG输出滤波器逆变器侧电感值仅需要二电平时的2/3。在此基础上根据装置无功补偿能力、谐波抑制要求以及三电平SVG输出电流特点提出一种三电平SVG输出滤波器设计方法,使其在满足无功补偿能力的前提下,采用较小的电感实现较好的滤波效果。最后通过仿真与实验证明提出的设计方法的可行性。

In this paper, the main circuit structure and modulation method of three-level static var generator （SVG） is studied. Output harmonic current and ripple current of three-level SVG are analyzed and the formula of output current of three-level inverter is given by use of double Fourier tools. Through the calculation of the output ripple current, it is known that the inductance of the inverter side needed for a three-level SVG is only 2/3 of that for a two-level SVG to achieve the same current tipple. A design method for three-level static var generator （SVG） is proposed based on the reactive power compensation ability, harmonic suppression requirements of the equipment and the characteristics of the output current of the three-level SVG. Some parameters are designed for better filtering effect with relative small inductance under the premise of meeting requirements of reactive power compensation ability. Finally, the feasibility of the proposed design method is demonstrated by simulation and experiment.