两电平静止无功发生器连接电感计算方法研究

Research on Calculation Method of Connecting Inductance of Two-Level Static Var Generator

连接电感作为静止无功发生器的关键设备,具有存储能量并双向馈送、调节输出电流相位、抑制高次谐波电流等作用,不仅影响静止无功发生器(SVG)的动、静态响应,而且还制约着SVG的输出功率、功率因数以及直流侧电压。目前SVG连接电感的参数选择是从谐波特性和经济性的角度,取其电感标幺值为0.2~0.5,没有实际的理论计算依据。从SVG无功输出容量和SPWM调制比的角度出发,推导出了连接电感的上限值,再综合满足谐波抑制指标时的电感下限值,给出了一种SVG连接电感的设计方法。通过仿真验证了采用本方法设计的连接电感值是正确合理的。

Connecting inductance is the key equipment of static var generator,it has the function of storage energy and bidirectional feed,adjusts the output current phase,inhibits the high harmonic current and so on.It not only affects the dynamic and static response of SVG devices,but also restricts the SVG output power,power factor and DC side voltage.Currently,the parameter selection of connecting inductance is from the corner of harmonic characteristics and its economy,in which the inductance value usually taken is 0.2~0.5 p.u.,lacking in practical basis for theoretical calculations.This paper deduces the upper limit of connecting inductance from SVG output capacity and SPWM modulation ratio,then gives the designing reference of SVG connecting inductance combining with the lower limit which satisfies the harmonic suppression index.At last,the correctness of the connecting inductance’s design method is verified through simulation.