微网变流器并网/孤岛模式平滑切换的锁相环技术

Phase-Locked Loop for Smooth Transition Between Grid-Connected and Island Operation Modes of Microgrid Converter

微网的并网和孤岛运行模式之间的平滑切换是安全稳定运行的重要保障,其中相位的精确控制至关重要。首先介绍了一种提取电网电压正序分量的锁相环技术—基于二阶广义积分的锁相环技术(DSOGI—PLL),在此基础上提出了适用于微网变流器的锁相环技术,该技术优点在于能够在并网时非理想电网条件下正确锁相;能够在孤岛模式下输出期望的频率和相位,而且能够实现在两种模式间平滑动态的切换。基于MATLAB Simulink的仿真验证结果表明,提出的锁相环技术输出动态响应快,过渡过程平滑无冲击,能够在非理想电网电压条件下准确跟踪电网相位,满足了模式无缝切换的要求。

Microgrid is an effective approach to solve the grid-connection of distributed generations.The smooth transition between the grid-connected and island operation modes of microgrid is an important measure to ensure the secure and reliable operation of microgrid,in which the phase-locked loop （PLL） plays an important role.This paper introduces a PLL model for extracting the positive sequence component of the grid voltage known as DSOGI-PLL,and then proposes an adaptation of the method to guarantee the smooth transition between the grid-connected and island operation modes.Finally,simulation results based on MATLAB simulink confirm the effectiveness and feasibility of the proposed PLL model.