基于RTDS的光伏发电系统低电压穿越建模与控制策略

摘要

基于实时数字仿真器（RTDS）提出了一种光伏发电系统低电压穿越（LVRT）实时数字仿真方案。首先，通过RTDS的大步长模型和小步长模型构建了整套LVRT仿真平台，具体包括电压跌落发生器、光伏阵列、隔离变压器和光伏并网逆变器等。然后，设计了光伏并网逆变器在三相电网电压正常和对称跌落2种运行工况下的LVRT控制策略。最后，以一台250kW光伏并网逆变器为例，进行了LVRT仿真测试和现场检测实验。仿真和实验表明：该RTDS仿真平台能较好地模拟现场检测平台，且所述控制策略在LVRT过程中具有良好的动、静态特性。%Based on the real time digital simulator (RTDS), a low voltage ride-through (LVRT) real time digital simulation scheme is presented for the photovoltaic generation system. A set of LVRT simulation platform including the voltage sag generator, photovoltaic array, isolation transformer and photovoltaic grid-connected inverter, is built by RTDS big step models and small step models. A LVRT control strategy is designed to ensure the photovoltaic grid-connected inverter operate in three- phase grid voltage' s normal and symmetrical drop conditions. Finally, the LVRT simulation test and field experiment have been carried out for a 250 kW photovoltaic grid-connected inverter. The simulation and experiment results show that the RTDS simulation platform is able to simulate the on-site testing platform and the proposed control strategy has good dynamic as well as static characteristics in LVRT process.