基于DIgSILENT的并网光伏发电系统的建模与仿真

基于DIgSILENT仿真平台搭建了适用于动态仿真的并网光伏发电系统的工程用数学模型,包含了光伏阵列、逆变器及其控制系统模型。该系统采用电压外环电流内环的双闭环控制方法,直流电压外环用于实现光伏电池最大功率点跟踪,交流电压外环用于控制输出的无功功率。最后,结合算例,研究了实际光照强度变化、电网有功调度及电网电压跌落时光伏系统的输出特性。仿真结果表明,采用的仿真分析方法切实有效,模型输出与实际输出基本相似。该模型能够很好地实现最大功率跟踪、快速地响应电网调度指令,电网电压跌落时还可提供一定的无功功率,可用于实际光伏发电系统的并网分析,为实际工程研究奠定了基础。

Modeling and simulation of grid-connected PV system based on DIgSILEN software

An engineering analytical model applied in dynamic simulation of the grid-connected photovoltaic system is established based on the DIgSILENT software, including PV array, inverter and the control system. The system adopts the double-loop feedback control with the inner-loop of current, the outer DC-voltage loop tracks the maximum power point of PV cells while the AC-voltage loop controls the reactive ouput. At last, the output characteristics of PV power generation system are analyzed under the variation of actual solar radiation, the dispatch of the active power and grid voltage dips. The results of the simulation show that the proposed method is practical and valid, the model output is similar to the actual one basically. This system can track the maximum power point automatically with high accuracy and response to the grid dispatching center rapidly, and provide reactive power during the voltage dip. It can be applied in paralleling operation analysis of photovoltaic system and makes a good groundwork for the practical engineering research.