Application Of SiC Components In Distributed Photovoltaic Micro-inverter

With the increasing of power demand and the exhausted of non-renewable energy sources in the world,renewable energy sources more and more draw public attention,such as solar energy and wind energy,etc..Because of the advantage of cleanliness,environmental protection and renewableness,etc.,solar energy becomes the most promising green energy internationally.At present,the main way to take advantage of solar energy is photovoltaic power generation.The conventional photovoltaic system has hot spot effect and a lower power generation efficiency.The appearance of micro-inverter solves these problems well.Micro-inverter as a critical part of distributed photovoltaic grid tied system,its reliability and conversion efficiency has a significant impact on the performance of the PV system.As an important component of the energy conversion and transmission of micro inverter,power switching devices are an important factor affecting the conversion efficiency and reliability of the micro inverter.With the advantages of lower on-resistance,wider forbidden band,faster switching speed as well as bearing higher voltage and temperature,the new Si C power devices have a very important role in improving the efficiency and reliability of the micro inverter.In order to effectively reduce the losses of power devices,improve the efficiency and reliability of PV systems,the Si C power devices are applied to the distributed PV micro-inverter in this paper,and the effect of the application of the SiC device on the efficiency of the micro inverter is studied.Firstly,SiC devices and their applications both at home and abroad are discussed in this paper,it introduces distributed generation system as well as the working principle and basic structure of micro-inverter.Secondly,several topologies of micro-inverter are discussed,and then,it chooses the main topologies of active-clamp flyback and full-bridge,photovoltaic grid tied micro-inverter using SiC power devices is designed.Because of the different characteristics of Si and SiC devices,the driver circuit for SiC devices is studied and designed in this paper,it focuses on analyzing the losses in DC /DC stage and DC / AC stage of the micro-inverter using SiC power devices,include the switch losses,transformer losses and the rectifier diode losses,etc..Finally,based on the simulation software,the two kinds of micro-inverter for Si and SiC power devices are compared and analyzed.The simulation results show that the application of SiC power device has a significant effect on the efficiency improvement of micro inverter.