低压微网中三相光伏并网逆变器控制策略研究

在低压微网中,以三相光伏并网发电系统为对象,分析了三相光伏并网逆变器的数学模型。并网逆变器电流内环采用瞬时电流控制,可以实现系统电流动态跟踪,但是电流内环采用传统PI控制需要功率前馈解耦影响和复杂旋转坐标变换。在瞬时电流控制的基础上,对三相光伏并网逆变器提出一种外环为瞬时功率控制、内环为瞬时电流准比例谐振的控制策略,并采用复传递函数方法分析了PR控制器的动态性能。经过仿真分析,外环瞬时有功无功控制实现了光伏并网逆变器参考功率控制;在光伏并网发电系统输出功率发生突变的情况下,电流内环控制具有快速准确动态跟踪性能,并实现了功率解耦控制,为电网输出高质量电能,仿真结果有效验证了该控制策略的效果。

Study on control strategy of three-phase photovoltaic (pv) grid inverter in low voltage micro-grid

In low voltage micro grid , three-phase photovoltaic (pv) grid power generation system as the object, the mathematical model of three-phase photovoltaic (pv) grid inverter is analyzed. Grid inverter current inner ring use the instantaneous current control which can realize the current dynamic tracing system, but the current inner ring user the traditional PI control to power feed-forward decoupling effect and complex rotating coordinate transformation. On the basis of the instantaneous current control, in this paper, the three-phase photovoltaic (pv) grid inverter is proposed a outer ring for the instantaneous power control, the inner ring for instantaneous current control strategy of proportion of quasi resonant. Through the simulation analysis, instantaneous active reactive power control loop reference for photovoltaic (pv) grid inverter power control; In photovoltaic (pv) grid power system output power under the condition of mutations, current inner loop control is fast accurate dynamic tracking performance, and realize the decoupling control of power, output power, high quality for power grid simulation results validate the control strategy of effective effect.