一种新颖的三相不平衡电网的锁相方法  

A NOVEL PLL FOR UNBALANCED THREE-PHASE GRID VOLTAGE

作　　者：王鹿军[1] 林辉品[2] 金利祥[2] 吕征宇[2] 

机构地区：[1]中国舰船研究设计中心,武汉430000 [2]浙江大学电力电子技术国家专业实验室,杭州310027

出　　处：《太阳能学报》2014年第12期2455-2460,共6页Acta Energiae Solaris Sinica

基　　金：国家自然科学基金(51177148)

摘　　要：针对电网故障时可能出现的三相电网电压不平衡的情况,提出一种静止坐标系下通过梯度下降法直接估测正负序分量的方法。该方法结构简单,无需将电网电压变换到同步旋转坐标系下,在静止坐标系下通过数值算法求解根据梯度下降法原理得到的非线性方程组,进而直接估测出正负序分量的幅值、相位和频率。通过实验评估该锁相方法的性能,实验结果表明,所提方法在电网发生不平衡故障时,具有较快的响应速度,即使电网电压在故障后相位、幅值和频率均有大幅跳变时,锁相环也基本能在两个工频周期以内完成锁相。Because the three-phase voltage may become unbalanced when grid faults, a method to estimate positive and negative components with gradient descent algorithm in stationary reference frame is proposed, which has a very simple structure and need not transforming grid voltage to synchronous reference frame. The nonlinear equations are obtained through the numerical algorithm solving in static coordinate system according to gradient descent principal. Then it can estimate the amplitude, phase angle and frequency of positive and negative components. The performance of the proposed phase-locked loop （PLL） is verified by experiments, and the experimental results show that the proposed PLL has a quick response when grid voltage suddenly becomes unbalanced. The response time of the PLL is within two frequency cycles even if all the amplitude, phase angle and frequency have large changes

关 键 词：梯度下降法 锁相环 不平衡 电网故障 

分 类 号：TM46[电气工程—电器]