基于改进型软件锁相环的正负序分量分离新方法研究

摘要

In view of the traditional separation method for the positive and negative sequence separation has the shortcomings of poor versatility when the power grid is unbalanced,so we propose a new approach based on improved SPLL for separation of the positive and negative sequence component.It uses the better filtering effect of the second order generalized integrator for high times and positive and negative sequence cascade characteristic of DSC harmonic elimination by αβ transform and dq transformation,and then,it uses the software phase-locked loop principle to lock the frequency of the grid and feedback to the second-order generalized integrator and negative sequence cascade of DSC to separate the positive and negative sequence component of grid.This method can fast and accurately separate the fundamental component of positive and negative sequence under the conditions of grid voltage symmetrical,asymmetrical fault and power grid voltage frequency change,which can provide reliable control signal for power electronic converter control system.MATLAB/Simulink software simulation results show that the proposed method is feasible and effective.%针对电网不平衡时传统正负序分离方法通用性不佳的缺点,提出了一种基于改进型软件锁相环的正负序分量分离的新方法,它利用二阶广义积分器较好的高次滤波效果、正负序级联的DSC谐波消除特性,通过αβ变换和dq变换,再利用软件锁相环原理来锁定电网的频率,并反馈给二阶广义积分器和正负序级联的DSC,从而分离出电网的正负序分量.由于本方法在电网电压平衡、不平衡以及电网电压频率变化等电网所有可能发生的故障情况下,都可以快速而准确的分离电网的正负序的基波分量,从而可为电力电子变流器的控制系统提供可靠的控制信号.最后MATLAB/Simulink软件仿真结果证明了所提出方法的可行性和有效性.