Research On Inverter For Independent Solar Energy System

In recent years,photovoltaic power technology has widespread application, along with our country's new energy law enacted,photovoltaic power system will have broader development space in our country.Inverter is an important component in photovoltaic system,its performance has great influence on photovoltaic system application.At present,the domestic pure sine wave output inverter mainly uses 50HZ transformer for raising the output voltage,with large size,heavy weight and higher price,making it difficult to adapt to technological development and market demand.Therefore,this thesis developed an inverter by using the "full bridge circuit +high frequency transformer +full bridge inverter" design proposal,which help to reduce system volume and increase system efficiency.For the feature of the inverter system,firstly,choose the proposal of the independent solar energy system;After choose the proposal,establish the mathematical model on the major components of inverter and PWM device;Then analyze the characteristic of single voltage loop and double closed loops of voltage and current,ascertain the transfer function of the current regulator for single voltage loop and the current-voltage regulator for double closed loops by engineering design method of continuous system,and set parameters for the current regulator and the voltage regulator by the best design of the engineering design method;Finally, simulate the current loop and voltage loop by Matlab,the Matlab simulation shows that the current and voltage loop are approximately in accordance with the best design of the engineering design method,also the double closed loop's stability and speediness of the independent solar energy system is better than single current loop.After getting the inverter's control scheme through the analysis of the independent solar energy system,this thesis give a design for the whole inverter system.This system uses the TI company's DSP TMS320LF2407 as the independent solar energy system's control core.In the DC-DC part,this thesis uses the full bridge circuit,discussed the selection of the power tube,the design of the high-frequency transformer and the selection of the rectifying tube.In the DC-AC part,in order to generate high-quality voltage waves,and decrease the harmonic component of voltage waves,this thesis uses the IPM power module,and simplifies the drive circuit design,and increase the system's capacity of resisting disturbance.Because the main function of the system is realized by DSP,so it decreases the volume of the system, increase the reliability of the system,and has the advantages of easy to upgrade, extendible,and good maintainability.