光伏发电并网同步锁频环技术研究

Research on synchronization frequency locked loop of PV power system

针对光伏发电的低电压穿越控制要求,研究能够适应于电网电压不平衡情况的电压快速准确检测方法显得格外重要。分析了不同锁频环技术的工作原理,并在Matlab/Simulink仿真平台中分别搭建了基于双二阶广义积分器的锁频环(DSOGI-FLL)模型、基于级联二阶广义积分器的锁频环(Cascaded-SOGI-FLL)模型以及基于降阶谐振调节器的锁频环(ROR-FLL)模型。通过重点模拟电网电压不平衡情况,对三种锁频环技术进行了对比仿真研究。结果表明:DSOGI-FLL和ROR-FLL响应速度快,适应电网电压跌落与频率突变的情况;Cascaded-SOGI-FLL响应速度相对较慢,适应电网电压存在谐波的情况。

According to the control requirements of the low voltage ride-through for photovoltaic power generation, it is very important to study the fast and accurate detecting method of the voltage under the unbalanced grid voltage. This paper analyzes the different working principles of frequency locked loop technology. Meanwhile, simulation models of dual second order generalized integrator frequency locked loop （DSOGI-FLL）, cascaded second order generalized integrator frequency locked loop （Cascaded-SOGI-FLL）and reduced order resonant regulator frequency locked loop （ROR-FLL） are established by using Matlab/Simulink platform. By simulating the imbalanced grid voltage situation, this paper compares the simulation results of three kinds of frequency locked loop technology. The results show that the DSOGI-FLL and ROR-FLL methods have fast response speed and can adapt to the situation of the grid voltage drop and frequency change, the Cascaded-SOGI-FLL has relative slow response speed and can adapt to the situation of the grid voltage existing harmonic.