Research On Design And Optimization Strategy Of Grid-Connected Photovoltaic Micro-inverter

As a clean pollution-free energy, solar energy’s development is getting more and more global attention. The study of solar photovoltaic power generation technology has been expanded extensively.This paper has made detailed exposition the research’s significance and the advantages of the photovoltaic grid-connected micro-inverter, as well as its key technologies. And also it describes the various components of the micro-inverter. We make a concise description of the several common DC/DC converter topology to determine of the interleaved flyback topology as the overall framework of the paper. At last, the main circuit design and other circuits, which the micro-inverter uses in this paper, are given.In the aspect of control strategy, in this paper, we divide the overall control architecture into modules. The paper of the entire control architecture module division, a state machine to determine the mode of operation of the system, and elaborated on the working mechanism of the state machine. And it is proposed that state machine is to determine the work modes of operation system, and then we elaborate on the working mechanism of the state machine, at the same time determine the disturbance observer method as the maximum power point tracking control structure. The current control is the most important aspects in the control system micro-inverter, control objectives; control is herein elaborated, by contrast, the average current mode as the overall control strategy. In this paper, control targets, general control strategy has been elaborated. By contrast, we choose the average current mode as the overall control strategy, and then give the control mechanism of several key modules; at last, we establish a Matlab Simulink model of the cotroll structure, and make a system simulation, the tracking effect is obvious.On system’s optimization, this paper presents a new idea based on the structure of the system. In this paper, we analyzes the pros and cons of the traditional incremental conductance method for maximum power point tracking, and proposes an improved MPPT method of conductance increment and adds a factor of variable step, and uses FPGA to achieve a circuit structure based on this solar MPPT algorithm. The improved control algorithm enables the system to improve 10.14% of the accuracy of the output power, this result is consistent with theory, and the system designed basically meets the design requirements。 And based on introducing the principles and pros and cons on the basis of the micro-inverter solar photovoltaic system, This paper presents a new idea based on the structure of the system, it depends on the size of the input power to determine the connection mode between solar panel group with photovoltaic Micro-Inverter group. Compared with existing technology, the paper provides the technical solutions which can greatly enhance the operating voltage range of the solar photovoltaic system, also it increases the length of time when micro-inverters work at the high conversion efficiency. So it has important practical significance.