计及阻尼和角速度的锁相环暂态同步稳定性分析与提升方法

Analysis and Enhancement Method for Transient Synchronization Stability of Phase-locked Loop Considering Damping and Angular Velocity

电力电子装置在电网中渗透率的不断提高导致电网强度和惯量降低,电网故障下暂态同步稳定问题日益突出。针对弱电网故障下并网逆变器的暂态失步问题,建立了计及锁相环阻尼和故障瞬间初始角速度的并网逆变器暂态同步模型,分析了锁相环阻尼和初始角速度变化对暂态同步稳定性的影响规律。提出了基于频率偏差反馈矫正的锁相环附加阻尼控制方法,以提升并网逆变器的暂态同步稳定性。针对不存在稳定平衡点的严重电网故障带来的暂态失步问题,提出了锁相环输出角速度动态补偿方法,实现了故障恢复后系统的稳定运行。最后,搭建硬件在环实验平台,对理论分析和控制方法进行了验证。

The increasing penetration of power electronic devices in power grids has led to a decrease in grid strength and inertia,and the transient synchronization stability problem under grid faults is becoming more and more prominent.To address the transient loss problem of grid-connected inverters during weak grid faults,a transient synchronization model for grid-connected inverters is developed considering the phase-locked loop damping and the initial angular velocity at the moment of fault occurrence.The influence law of variations in phase-locked loop damping and initial angular velocity on transient synchronization stability is analyzed.Furthermore,an additional damping control method of phase-locked loop based on the feedback correction of frequency deviation is proposed to enhance the transient synchronization stability of grid-connected inverters.To address the transient loss problem posed by serious grid faults without stable equilibrium points,a dynamic compensation method for output angular velocity of phase-locked loop is proposed to achieve the stable operation of the system after fault recovery.Finally,a hardware-in-the-loop experimental platform is constructed to verify the theoretical analysis and control methods.