The Research On Nonisolated Grid-Connected Photovoltaic Inverter

With the growing demand for energy, making the distributed generation is becomingincreasingly important, such as solar power, wind power generation. In distributed generationsolar power which plays an important role. The solar photovoltaic solar power generation is amajor power generation. In the solar photovoltaic power generation systems, photovoltaicgrid-connected inverter is a critical part of its low conversion efficiency, reliability, qualityand production cost of the entire grid system and so would have a significant impact.Therefore, the solar photovoltaic inverter technology research has very important significance.This paper studies the non-isolated PV grid-connected inverter in the common mode leakagecurrent.The article first describes the non-isolated transformerless grid-connected PV inverter,the common mode leakage current and parasitic capacitance causes the problem.Subsequently, the existing suppress common mode leakage current of single-phase topologyis analyzed and studied. On this basis, we propose a modified single-phase topology, and itsdetailed analysis and simulation. Then describes several existing three-phase topology, and avariety of topologies are analyzed and compared. Finally, the solar cell output characteristicsof a theoretical analysis and the establishment of a mathematical model. Also analyzedseveral common maximum power point tracking (MPPT) control method, introduced animproved disturbance observer method, and its theoretical analysis and simulation. Analysisof several grid-connected inverter current control method, and using two different currentcontrol methods proposed in this paper an improved single-phase topology of the simulation.Found by simulation, this paper presents an improved single-phase topology can effectivelysuppress common mode leakage current, which is the actual system to solve leakage currentissues have a good theoretical reference value.