三相有源电力滤波器错序校正策略

当并联有源电力滤波器(Shunt Active Power Filter,SAPF)接入电网时相序错接,将导致锁相环无法正确锁相,不能正常进行谐波抑制与无功补偿。为了解决这一问题,文章分析了网侧电压相序对SAPF的影响,推导出同步旋转坐标系下的电压d轴与q轴分量,提出了利用同步旋转坐标变换与滑窗平均滤波器由软件实现的相序检测方法。同时针对相序检测方案的性能进行了研究,得出滑窗滤波器窗口长度与相序判断阈值间的关系及判断SAPF网侧电压相序的判断原理。在获得了电网相序的基础上,设计了三相SAPF错序校正策略,使得SAPF在正序与负序电压下都能够正常抑制谐波,最后通过实验验证了理论分析的正确性。

Phase sequence correction strategy for three-phase active power filter

When the grid side voltage is in the negative sequence, the shunt active power filter (SAPF) could not lock the phase of the voltage to compensate harmonics and reactive power. In order to solve the problem, this paper firstly analyzes the influence of the phase sequence of the grid side voltage on the SAPF. The d axis and q axis voltage component in synchronous rotating coordinate system are deduced. A phase sequence detection method based on synchronous rotation coordinate transformation and sliding window average filter is proposed, which is implemented by software. At the same time, the performance of the phase sequence detection scheme is studied. The relationship between the sliding window average filter and the threshold of the phase sequence judgment is obtained. On the basis of obtaining the phase sequence of power grid, a three-phase SAPF phase sequence correction strategy is designed in this paper, which enables SAPF to compensate harmonics normally in both the positive and negative sequence. Finally, the correctness of the theoretical analysis is verified by simulation and experiment results.