具有频率自适应改进的FBD谐波检测方法的研究

Research on the improved FBD harmonic detection method with frequency adaptive algorithm

针对传统FBD检测方法中锁相环引起的误差和延时问题,研究了一种改进的无锁相环的FBD谐波检测方法。该方法采用正弦幅值积分器代替锁相环,在αβ坐标系下对电网电压的幅值进行积分,得到与基波电压正序分量同步的信号,进而检测谐波分量。同时,为了避免电网频率波动对谐波检测精度的影响,通过引入锁频环,构造了频率自适应环节。与传统方法相比,该方法结构简单,动态响应快。仿真实验表明,当电网电压不对称或频率波动时,该方法可以准确、快速地检测出谐波电流分量。

To solve the problem of error and delay caused by the phase-locked loop in the traditional FBD detection method,an improved FBD harmonic detection method without phase locked loop is proposed. The sinusoidal amplitude integrator( SAI) is used to replace phase locked loop( PLL),and the amplitude of the grid voltage is integrated under αβ coordinate system for the sake of signal synchronized with the fundamental positive sequence voltage. Then the harmonic component can be detected. At the same time,in order to avoid the influence of power grid frequency fluctuation on harmonic detection accuracy,a frequency locked loop is introduced to structure frequency adaptive link. Compared with the traditional detection methods,this method has simple structure and fast dynamic response. The simulation experiments show that the harmonic current component can be detected accurately and quickly under the circumstances of the grid voltages unbalanced or frequency fluctuating.