基于瞬时电流跟踪的三相光伏逆变器并网控制策略研究

摘要

在分析光伏逆变器交直流侧的能量传递关系基础上，提出一种基于瞬时电流跟踪方式的并网控制策略。该策略的功率外环考虑到了光伏方阵模块的功率变化及直流电容器的充放电过程等因素，内环采用滞环电流控制的方式对参考电流进行跟踪，具有电流谐波小、响应速度快、控制参数容易整定等优点；同时给出了光伏逆变器的启动控制策略，防止启动电流过大损坏功率开关器件。最后在 PSCAD/EMTDC 中建立了三相光伏并网系统的仿真模型，数字仿真验证了以上控制策略的有效性。%On the basis of analyzing energy transferring relationship between AC side and DC side of the photovoltaic invert-er,this paper proposes a kind of grid-connection control strategy based on instantaneous current tracking.The outer loop of power of this strategy considers factors such as power transformation of the photovoltaic array module and charge and dis-charge process of the DC capacitor,the inner loop uses hysteresis current control mode to track reference current.This strategy has advantages such as small current harmonic,rapid response speed,easy setting on control parameters,and so on. Meanwhile,this paper provides start control strategy for photovoltaic inverter in order to prevent large start current from damaging power switching elements.In PSCAD/EMTDC software,simulation model for three-phase photovoltaic grid-con-nection is established and digital simulation verifies effectiveness of this control strategy.