逆变器的控制在光伏并网系统中起着核心的作用,在三相光伏并网系统的基础上对并网逆变器提出了一种直接功率控制的方案.直接功率控制(DPC)仅需要测量交流侧的电压与电流,通过坐标转换,计算出瞬时有功功率与无功功率,得到的结果分别与PI调节得到的参考有功功率以及给定无功功率进行比较,经过滞环比较器,开关表等环节来控制并网变流器.Matlab/Simulink仿真结果表明,并网逆变器直接功率控制方法简单,并网功率因数接近于1,电流谐波小,具有良好的动态和稳态性能.%Inverter control plays a central role in the photovoltaic grid system. This paper poposes a direct pow-er control scheme of grid-connected inverter on the basis of the three-phase photovoltaic grid system. This study measures the voltage and current of the AC side,calculates the instantaneous active and reactive power through coordinate conversion,then compares the results with respectively the reference active power obtained in PI reg-ulator and given reactive power,and finally completes the grid inverter control by a lag ring comparator and switch table links. Matlab/Simulink simulation results show that the grid-connected inverter direct power con-trol method is simple with good dynamic and steady performance,and network power factor is close to 1 with small current harmonics.
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