增强型锁相环的启动优化和相频解耦改进算法

Start-up optimization and phase-frequency decoupling strategy forenhanced phase-locked loop

锁相环结构中相位和频率紧密耦合,在电网处于干扰或短时故障工况下,同步频率的波动直接影响锁相的性能。基于假线性增强型锁相环(pseudolinear enhanced phase-locked loop,PL-EPLL),提出了一种适时解除相位和频率耦合的改进算法。该算法能够在设计锁频范围内,增强频率同步的稳定性和抗干扰能力,提高锁相的动态性能。另外,针对PL-EPLL具有两个相位锁定状态的特点,在算法实施上采用一种同步相位初始值优化设置,在初始相位差较大的情况下能够有效提高锁相算法的启动速度。最后,通过仿真和实验验证了改进算法的有效性。

In this paper,a modified pseudolinear enhanced phase-locked loop(PL-EPLL)is proposed to improve the performance of PLL synchronization when the power grid is under non-ideal condition,such as disturbances and faults. The modification is based on a timely-decoupling strategy between the estimated phase-angle and the estimated frequency,for which in a designable frequency-locked range,the robustness of frequency synchronization is enhanced and the dynamic performance of PLL is improved. In addition,based on the feature that PL-EPLL has two different phase-locked points,an optimized setting of the initial value of the estimated phase-angle is introduced in this paper,which can statistically improve the start-up speed of the PL-EPLL algorithm. Finally,the feasibility of the proposed method has been verified by simulation and experimental results.