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针对常规锁相方法在电网异常时不能有效地检测出电网相位和幅值的问题,采用自适应滤波器提取电网电压的正序基波分量,根据正序基波分量检测电网的相位和幅值.针对电网相位突变的情况,在分析锁相环数学模型的基础上,提出了电网正序电压的q轴分量的直接前馈方法,有效地提高了系统的动态特性和相位检测精度,并从理论上分析了电网幅值变化对锁相环的稳定性和稳定裕度的影响.仿真结果证明了所提锁相方法的可行性.
Aiming at the problem that the conventional phase-locked method can not detect the phase and amplitude of the power grid effectively when the power grid is abnormal, an adaptive filter is used to extract the positive sequence fundamental components of the grid voltage and the phase and amplitude of the grid based on the positive sequence fundamental components Aiming at the situation of phase abrupt change in power network, a direct feedforward method of q - axis component of grid positive sequence voltage is proposed based on the analysis of the mathematical model of phase - locked loop, which can effectively improve the dynamic characteristics and the phase detection accuracy of the system. The influence of power system amplitude on the stability and stability margin of the PLL is theoretically analyzed.The simulation results show the feasibility of the proposed phase-locked method.