基于稳定性分析的微电网变流器系统阻抗设计

为解决微电网线路阻抗呈现阻性所带来的稳定性问题,采用控制提高微电网变流器的感性等效阻抗的方法被广泛应用.本文提出了一种微电网变流器系统阻抗设计方法,将微电网变流器的阻抗划分为内部阻抗和外部阻抗两部分.内部阻抗由微电网变流器的电压电流控制器、变流器侧滤波电感和滤波电容组成,外部阻抗由电网侧滤波电感和虚拟电感组成.采用伯德图对微电网变流器的内部阻抗传递函数进行了分析,得到了影响其阻抗特性的关鍵参数并给出了参考取值.建立微电网变流器并网状态下的小信号模型,给出了可提高微电网变流器稳定性的虚拟电感取值范围,采用定量法分析了控制参数变化对虚拟电感取值范围的影响.最后通过实验验证了设计方法的正确性.

Design of microgrid converter system impedance based on stability analysis

In order to solve the stability problem arisen by resistance microgird hne impedance, Usingcontrol method to improve microgrid converter system inductance is widely applied. This paper introduces a kind of design method for microgrid converter system impedance which divided into internalimpedance and external impedance. The internal impedance consists of voltage and current controller,filter inductance of converter side and filter capacitance. The external impedance consists of the filterinductance of grid side and virtual inductance. The internal impedance character is analyzed by Bodediagram. The key parameters of internal impedance character are acquired and the reference value isgiven. The microgrid converter system stability is analyzed using a smallsignal model. This paper alsogives the connection between the parameters change and virtual inductance range. Experimental resultsshow the effectiveness of this study.