基于模型电流预测控制的光伏电站低电压穿越控制方法

摘要

在传统光伏电站低电压穿越技术之上，提出了一种基于模型电流预测控制的光伏并网逆变器低电压穿越控制方法，模型电流预测控制方法能够使逆变器的输出电流迅速地跟随参考电流指令，具有良好的动态特性。在光伏电站并网点发生故障期间，能够迅速控制光伏电站无功功率的输出，为并网点提供电压支撑，减少无功设备的投资，同时也提高了系统的暂态稳定性。在 PSCAD/EMTDC仿真平台上进行了三相短路故障、单相短路故障和大负荷扰动3个仿真实验，另外对模型电流预测控制的输出响应和稳态性能进行了仿真分析，仿真结果表明，光伏电站在低电压期间为电网提供电压支撑，验证了所提出控制方法的有效性。%On the basis of traditional low voltage ride through(LVRT)technology of the photovoltaic plant,a method based on model current predictive control (MCPC) for improving the ability of grid-connected inverters’ low voltage ride through in photovoltaic plant is proposed.The MCPC method with its good dynamic characteristics is able to control the output current of the inverters in quickly following the reference current.During failure of the grid,MCPC can control the reactive power output of the photovoltaic plant to support the system voltage and reduce investment in the reactive equipment,while improving the transient stability of the system.Three-phase short circuit fault,single-phase short circuit fault and heavy load disturbance simulations are carried out on the PSCAD/EMTDC platform.In addition,the output response and steady-state performance of model predictive control are analyzed,the simulation results showing that during low voltage,the photovoltaic plant is able to support the voltage,proof that the proposed method is effective.