适用于微电网的并网逆变器动态电压支持功能研究

Dynamic voltage support function of grid-connected inverters for micro-grids

针对微电网在并网运行时易受外部主电网电压跌落影响的问题,本文提出了一种基于并网逆变器的动态电压支持方法。利用无功功率流过电感会产生压降的原理设计控制器与电路,当主电网电压发生跌落时在微电网不断网的前提下控制逆变器向电网注入一定量的无功功率,使其流过解耦电感产生与电压跌落幅度相当的压降,以支持微电网的本地电压。根据电压跌落幅度的不同,设计了控制器的不同动作来维持本地电压,保证负载的正常工作。文中详细阐述了控制器的设计原理,并利用MATLAB/Simulink对提出的并网逆变器动态电压支持功能进行了仿真分析,验证了该方法的可行性与有效性。

In order to restrain the negative impact of voltage sags of utility grid on micro-grids, a dynamic voltage support method based on grid-connected inverters is proposed in this paper. The controller and circuit are devel-oped to realize the principle that a voltage drop on the inductor is generated when the reactive power flows through it. Once the voltage sag of utility grid occurs, an arbitrary reactive power is injected into the grid by grid-connected inverters, which generates a voltage drop on the decoupled inductor to compensate the grid voltage sag. This can maintain the local bus voltage of micro-grids. According to the magnitudes of voltage sags, several actions of the grid-connected inverters are designed and implemented to generate reactive power and maintain local bus voltage, which ensures the normal operation of loads. Design considerations of the controller are discussed in detail. Simula- tions by using MATLAB/Simulink are conducted, which demonstrate the feasibility and effectiveness of the pro-posed method.