The Research Of Single-Phase Photovoltaic Grid Inverter

As oil,coal and other fossil energy is drying up, it is imminent that human being explore and develop new energy.Solar energy as a kind of renewable clean energy,which is wide distribution and large energy, so it is becoming more and more popular.However, if you want to turn solar energy into usable grid-connected alternating current. It need to find out a new photovoltaic grid inverter,so The study of photovoltaic grid inverter is very necessary.The significance of this study is to better optimize and upgrade the existing single-phase photovoltaic grid inverter output characteristics, As a result, the paper studies at the beginning of the first overview of single-phase photovoltaic grid inverter research status and development trend at home and abroad. At the same time, according to the characteristics of the medium and small power inverter,further defined the research of the specific steps, mainly on several typical single-phase photovoltaic grid inverter topology comprehensive comparative analysis of advantages and disadvantages, choose suitable type in this paper, two levels of isolation structure of single-phase grid inverter. Found in the comparison of existing structure problems of the inverter, so the two levels of the isolation structure, on the basis of added LCL filter and leakage current suppression module. Secondly, according to the designed topology structures, hardware circuit, here using TMS320F28035 chips as the main control unit, and use HCPL316 J, ACS758 chip as the IGBT drive and detection circuit. For single-phase photovoltaic grid inverter hardware integrity as a whole. Finally, the defect of traditional double closed-loop PI current control strategy, in-depth research. Find a loop control strategy of PI, the inner ring with no beat. Single-phase photovoltaic grid inverter, in order to make it adapt to the wider non-ideal grid environment, design a kind of considering frequency adaptive single-phase grid inverter based on improving the park transform phase-locked loop. By Matlab/Simulink simulation experiment, the application of this method of single-phase grid inverter, the power grid voltage drop, such as non-ideal harmonic injected into power grid voltage case, still can track, lock power grid voltage frequency and phase of the steady-state error is small, precision have higher advantages.