可改善并网逆变器系统稳定性的弱电网频率快速检测方法

现有的频率检测方法大多通过锁相环实现,但锁相环在弱电网背景下存在失稳隐患,致使弱电网频率无法准确检测。在电网同步相位开环检测方法的基础上提出了一种新的频率检测方法,可在有高频噪声干扰的背景下显著地提高频率检测的速度与精度。文中所提出方法首先利用开环相位检测技术实时准确获取电网同步相位,接着利用差频相位跟踪算法提取实时电网相位中的差频相位分量,最后通过对该差频相位信息进行闭环控制,即可快速准确地获得电网频率信息,实验结果表明:提出的频率检测方法能够快速准确地检测电网的实时频率,精度高且抗噪声干扰能力强。

A Frequency Detection Method of Weak Grid for Improving Stability of Grid-tied Inverter System

Higher requirements have been put forward on accuracy and real-time of frequency detection, because renewable energy access to the grid in large-scale. The existing frequency detection method must rely on the phase-locked loop (PLL), considering the problem of PLL in the background of power electronic, a new frequency detection method is proposed in this paper based on synchronous phase open-loop detection of power grid. In this method, the difference-frequency phase is extracted from the phase information obtained by the open-loop phase detection and difference-frequency is obtained by adjusting difference-frequency phase. The experimental results show that the proposed method can effectively detect the real-time frequency of the power grid, which has high precision and strong anti-interference ability.