Research On A Non-isolated Single-phase Boost Photovoltaic Inverter

In recent years,the large-scale mining and use of one-time fossil energy has led to a serious reduction,and the large consumption of fossil energy will also cause environmental pollution.Therefore,power generation with clean,pollution-free solar energy and wind energy and other renewable energy sources has attracted wide attention from all over the world.Among them,the installation of solar power generation devices is more flexible and convenient,and it has won everyone’s favor.In photovoltaic power generation systems,inverter is one of the key interface devices that convert DC power into AC power.Therefore,it is of great significance to study inverters with high reliability,high safety and high efficiency.Considering the structure of the inverter,if it is classified according to whether it contains an isolation transformer,it can be divided into an isolated photovoltaic inverter and a non-isolated photovoltaic inverter.Non-isolated inverters have the characteristics of small size,low weight and cost,and high efficiency,and have gradually gained the favor of the industry in the field of renewable energy power generation such as photovoltaics.However,the traditional non-isolated full-bridge inverter has the risk of bridge arms passing through,and it also brings leakage current problems,which affects the safety performance of the system.This article studies a single-input transformerless single-phase boost inverter,which can reduce the number of switching devices,and can avoid the bridge arm through phenomenon,and has high reliability.In addition,the inverter can effectively suppress leakage current,which is beneficial to improve the efficiency and safety of the system.On this basis,a transformerless single-phase boost inverter based on dual inputs is studied.Two input power sources can provide energy to the load at the same time or separately,which improves the redundancy of power supply on the input side.This paper analyzes the working principle and steady-state characteristics of the two inverters in detail,and further gives the analysis and calculation of the theoretical power consumption and leakage current of the converter.Secondly,in order to solve the problem of output zero-crossing distortion,a duty cycle compensation modulation method is studied.A state space equation is established for the proposed converter,and a double closed-loop control system is designed,so that the proposed inverter reaches a better operating state.Then,the main circuit parameters,control circuit and sampling circuit of the proposed inverter are designed.At the same time,the main program was compiled,and the flow chart of the main program is designed.Finally,through the MATLAB/Simulink platform,the simulation was carried out,and with STM320F2812 DSP as the core,two experimental prototypes were built,and the theoretical analysis was verified,and the experimental results were given.