电压畸变条件下软件锁相环精度提高

The Improving of Soft Phase Locked Loop Precision Under Voltage Disortion

串联补偿设备要求在电网电压畸变的条件下,能够准确地锁住电压基波正序相位。基于瞬时无功理论的软件锁相环(SPLL)技术是目前常用的锁相方法,但该方法有一定的误差。这里设计了一个低通滤波器(LPF),能够在电网电压存在谐波、跌落、直流分量等情况下高精度地锁相,从而使串联补偿设备获得较好的补偿效果。仿真和实验证明了该方法的精确性和可行性。

It is necessary to capture the phase of positive-sequence fundamental component of voltage accurately for series compensation devices,under voltage disortion.The software phase locked Ioop（SPLL） method based on the instan- taneous reactive power theory is commonly used,which has some errors.A low pass filter is added based on the anal- ysis and it can improve the SPLL precision under the condition that the sags, harmonics and DC component occur in power system.So a better compensation effect can be achieved by series compensation devices.Simulation and experimental results verify the accuracy and feasibility of the method.