小功率光伏并网逆变器反孤岛保护的研究

摘要

The improved active anti-islanding protection will affect the current power quality , and its protection is too complex , this paper proposed the anti-islanding protection method of combing the active and passive protection based on the detailed analysis of islanding detection principle , namely the passive anti islanding operation control plays a major role, when it fails, the active anti islanding control plays a protective role .The main process is as follows:first-ly, the voltage and frequency of the common coupling point is detected , and if the protection threshold is exceeded , the inverter is disconnected , if it does not go beyond , then using the detection method of voltage applications in com-mon connection point of the positive feedback , and we make a simulation contrast with the traditional frequency-based positive feedback frequency shift method , which primarily illustrates that the proposed method compared to the tradi-tional positive feedback frequency based on the frequency shift method is not inserted in the dead zone in the output current waveform , the simulation results not only validate the method of power quality is relatively less affected by the current network , and can effectively prevent the occurrence island effect .%文中针对改进型主动式反孤岛保护会对入网电流电能质量造成影响，改进型被动式反孤岛保护过于复杂，深入分析了逆变器孤岛运行的基本原理。然后提出了主被动式相结合的反孤岛保护检测方法。该方法主要工作过程为：检测公共耦合点处的电压和频率，比较其是否超出了保护阈值范围。若超出则控制逆变器断开防止其孤岛运行，没有超出则采用基于公共连接点处电压应用正反馈的检测法，并与传统基于频率正反馈频移法做出了仿真对比，主要是为了说明，本文所提出的方法相对于传统基于频率正反馈频移法没有在输出电流波形中插入死区，仿真结果不但验证该方法对入网电流的电能质量影响相对较小，并且能够有效地防止孤岛效应的发生。