为提高同步坐标系锁相环在谐波畸变电网环境下的控制性能,提出一种基于频率自适应滤波器的同步坐标系锁相方法。用数学解析方法证明了所用频率自适应滤波器的时域稳定性,讨论了滤波器的参数对其动稳态性能的影响。同步坐标系锁相方法的设计中,采用频率自适应滤波器在静止坐标系中分离出电网信号的基波正序分量,并在同步旋转坐标系中抑制锁相环输入信号中的2次谐波分量。该文基于频率自适应滤波器设计的同步坐标系锁相方法,实现了对谐波畸变电网中电网信号基波正序分量的精确锁相,且具有较快的动态响应速度。仿真和实验结果验证了所提锁相方法的有效性和可行性。
This paper proposed a novel synchronous reference frame phase-locked-loop (SRF-PLL) based on frequency adaptive filters to improve the control performance of the SRF-PLL under distorted grid conditions. Time domain stability of the adaptive filter was analyzed by method of mathematical analysis, and parameters determining the filter's dynamic and steady state performance were discussed. In design of the SRF-PLL, two adaptive filters separated the fundamental positive sequence component from the power signal in the stationary frame, and one attenuated the second harmonic contained in the input signal of the PLL in the synchronous frame. The SRF-PLL based on the frequency adaptive filter, realizes accurate phase lock of fundamental positive sequence in the power signal under distorted grid conditions, and also has fast dynamic response speed. The simulation and experiment show that the proposed phase locked algorithm effective and feasible.