带有谐波补偿功能的主动移频式孤岛检测法

Island detection by active frequency drift method with harmonic compensation

首先利用快速傅里叶变换分析了用于孤岛检测的传统主动频率偏移(AFD)法引起的谐波,基于分析结果,得出了传统AFD法引起的3、5、7次谐波电流的公式。通过引入与上述谐波电流相位相反的电流,对谐波进行补偿。给出了所提带谐波补偿功能的AFD法在数字化控制系统中的实现方法。仿真和实验结果表明,所提方法有效地减少了系统中的谐波电流,同时不影响孤岛检测。

The harmonic currents induced by the traditional AFD（Active detection are analyzed by fast Fourier transform and the formulas of Frequency Drift） its third-,fifth- method for island and seventh-order harmonic currents are obtained. Therefore,the currents with inverse phase can be applied to compensate the harmonic currents caused by the AFD method. The way to implement the AFD method with harmonic compensation in digital control system is introduced. Simulative and experimental results show that,the proposed method effectively reduces the harmonic currents without influencing the island detection.