适用于低电压穿越的新型锁相环

A Novel Phase-locked Loop Under LVRT Condition

随着新能源的不断发展,电网对其也有了更高要求。变流器的低电压穿越(LVRT)能力对于电网的稳定性极为重要。在电压跌落过程中,电网电压的幅值和相位均会发生变化,这种现象称为相位跳变。对于变流器的控制而言,快速准确地解析电网信息极为重要。因此,提出了一种新型的结合变结构技术的由锁相环(PLL)与相位调节两部分组成的软件PLL策略,实现了在快速追踪相位跳变的同时,有效减少输出频率波动的目的。仿真与实验均验证了该结论。

With the growing penetration of renewable energy resources, the grid operators place higher emphasis on their grid integration requirements.The low voltage ride through（LVRT） capability is one of the most important issues for maintaining the grid stability.During the process of voltage drops occur,as the output voltage amplitude change, the voltage phase angle will also be change ,which namely ＂phase angle jumping＂.The grid information tracking must be fast dynamic respond performance and high detection accuracy to improve the converter＇s performance.This paper proposes a new three-phase software phase-locked loop（PLL） that consists of a variable structure frequency detector and an initial phase angle detector, and responds fast to phase angle jumps with precise output frequency.Simulations and experiments verify the performances of the novel PLL.