基于虚拟磁链直接功率控制的光伏并网逆变器控制策略研究

Study on grid-connected inverter used in PV generation system based on virtual flux-linkage direct power control

将基于虚拟磁链直接功率控制策略VF?DPC(virtual-flux-linkage direct power control strategy)应用于光伏并网电压源型逆变器。引入虚拟磁链的概念并用于计算瞬时有功和无功功率,结合空间矢量SVM(Space Vector Modulation)技术,构成固定开关频率三相并网逆变器DPC控制策略。该方法不仅能够实现系统对有功功率和无功功率的直接控制,而且能保证固定的开关频率,简化了滤波器的设计,降低了对控制器和A/D采样的要求。仿真和实验结果表明实现了单位功率因数控制,电流谐波小,具有良好的动态和稳态性能。

This paper applies VF-DPC to voltage-sourced inverter of PV generation. Virtual flux is introduced into DPC structure to calculate active and reactive power and SVM is considered to establish constant switch frequency three phase grid-connected inverter DPC.The proposed method can realize the direct control for active and reactive power, operate under constant switching frequency, simplify the design of filter, as well as lower the controller and A/D sampling. Simulation and experimental results show that unity power factor is achieved and the proposed method has the advantages of low harmonic distortion of current, excellent dynamic and steady state performances.