三电平光伏并网发电系统漏电流抑制研究

Leakage Current Suppression for Grid-connected Three-level Photovoltaic Generation System

针对非隔离三电平光伏发电系统存在漏电流和中点平衡问题,提出一种有限集模型预测控制方法,实现光伏并网逆变器的正常并网运行。采用2个中矢量和1个零矢量实现漏电流抑制,与传统方法相比,该方法漏电流最低。三电平升压控制器实现中点电位平衡和直流侧电压控制;三电平光伏并网逆变器实现并网电流快速跟踪控制。仿真验证了所提控制算法具有快速的跟踪性能、直流侧电容电压平衡控制和漏电流抑制。

Aiming at the problem of leakage current and midpoint balance in non-isolated three-level photovoltaic power generation system, a finite set model predictive control method was proposed to achieve normal grid connected operation of PV grid connected inverter. The leakage current suppression was realized by two medium vectors and one zero vector. Compared with the traditional methods, the leakage current was the lowest. The three level Boost controller realized the middle point potential balance and the DC side voltage control,and the three level PV grid connected inverter realized the fast tracking control of the grid connected current. The simulation results show that the proposed control algorithm has fast tracking performance, DC side capacitance voltage balance control and leakage current suppression.