一种新型的单相并网系统锁相环

摘要

电网电压的相角、频率对并网逆变器而言是最基本的信息.准确快速地跟踪电网电压是并网控制系统稳定运行的保障.在单相并网逆变器中,常规的过零点检测锁相方法往往对电网电压畸变或扰动敏感,使得锁相环处于不稳定状态,从而导致并网逆变系统性能降低,甚至不能正常工作.针对此问题,分析了基于同步旋转坐标变换的锁相环原理,并将这种锁相策略应用于单相并网系统,仿真和实验结果均证明了此方法的有效性.%Phase angle, frequency of the utility voltage are basic information for grid connected inverters.Accurate tracking of the utility voltage vector is essential to ensure correct operation of the control system.In single phase grid connected power system,the software phase locked loop(SPLL) using zero crossing PLL strategy is instable when utility frequency fluctuates, which can cause the system performance degradation and even abnormally working.A new SPLL method based on synchronous reference frame(SRF) is proposed,and the simulation and experimental results demonstrate the feasibility of the phase-tracking action of the PLL method.