基于虚拟磁链的三相光伏并网逆变器控制策略研究

针对传统虚拟磁链观测器对电网电压积分后存在直流漂移与积分饱和现象,严重影响矢量精确定向的问题,设计了由低通滤波器和高通滤波器组成的虚拟磁链观测器代替电网电压传感器,可以有效减小谐波畸变,减少系统控制成本。对观测器进行仿真研究,表明观测器能消除积分饱和现象,消除直流分量对精确定向的影响,提高系统的动态性能;结合虚拟电阻法,改善LCL滤波器的性能,实现单位功率因数运行。

Research on Control Strategy of Three Phase Photovoltaic Grid-connected Inverter Based on Virtual Flux

To solve the dc drift and integral saturation phenomenon produce the error of the vector orientation problems in the traditional virtual flux observer, the virtual flux observer consisted of the low-pass filter and high-pass filter is designed. The observer instead of power grid voltage sensor in three-phase grid-connected inverter, can effectively reduce the harmonic distortion and the cost control system. The simulation was taken on the observer and showed that the observer can eliminate integral saturation phenomenon and the influence of the dc component on the positioning accuracy, and improve the dynamic performance of the system. The virtual resistance method combine with inverter can improve the performance of the LCL filter, and achieve unity power factor operation.