The Research Of Diminutive High Power Solar Inverter Based On Voltage Feedforward In A Weak Power Grid

With the gradual reduction of fossil energy and the environmental pollution becoming more and more serious,the development and utilization of clean energy have become the direction and consensus of global.The solar power has played a significant role in the promotion of new energy applications.In particular,for the development of domestic society in recent years,the concept of blue waters and green mountains is equivalent to assets,which is deeply rooted in the heart.The government and society are working hard to control the pollutions,and they are fully committed to recover our blue sky and white cloud.This has also promoted to the rapid development of the solar power industry,and the solar inverter as a very important device in the solar power system has also been developed rapidly.But with the increasing number of the solar inverter installation,it gradually exposes some problems,such as oscillating output current of the solar inverter under weak power grid,which increases the harmonics of the inverter output current.In severe cases,the output current of the inverter may be overcurrent and disconnected from the power grid.In addition,with the widespread applications of the household solar inverter and the guidance of poverty alleviation policies,the cost of solar inverter also limits the long-term development of the solar power industry.In this thesis,through the analysis and design of the solar inverter technology,a low-cost method for improving the applicability of solar inverter under the weak power grid was proposed.At the same time,this thesis also reduced the inverter's volume to realize the miniaturization of the inverter and increasing the reliability and aesthetics of the inverter by increasing the solar inverter switching frequency.The main research contents are listed as follows:(1)Research and analysis the overall solar inverter system,and present a solution to the miniaturization of the solar inverter by increasing the transistor switching frequency.Through analysis and calculation,it is determined that the switching frequency is set to 32 k Hz as the optimal solution.Transistor selection,inductance design,and drive circuit design were performed under this condition.The PCB layout is optimized to achieve the miniaturization of solar inverter.(2)Introduce and analysis the inverter output current control strategy detailed,and the characteristics of the inverter output current under weak power grid,as well as the cause of the oscillation.Propose a solution of adding in the lead-lag system in voltage feed forward,which solves the problem of inverter output current oscillation under weak power grid.(3)Finally,through the targeted test of the sample,verify the reliability of the high-frequency solution,and the stability of the inverter under the weak power grid.The output parameters of the solar inverter were tested to prove the product design performance meeting the requirements.