Research And Development Of Photovoltaic Grid-connected Inverter

Photovoltaic power generation technology with more and more people research and attention is going to mature. In the near future, photovoltaic power generation will play a vital position in the power sector. This combination of practical projects have been completed the depth and detailed study for photovoltaic grid-connected inverter topology, control methods and other issues, and completed the work of research and development the 50KW three-phase single-stage photovoltaic inverter. Include the following issues:(1) The analysis of the grid-connected photovoltaic power generation system, and the different structures of the inverter system. According to the requirements of the design, selected the inverter topology fitted for the research and development. On this basis, analyzed the working principle of the inverter. Lay a good foundation for the next working of the entire system.(2) Analyzed the control objectives of the grid-connected inverter, and then analyzed in detail a variety of different control strategies. For the existing problem of three-phase current control, established the mathematical model of three-phase grid-connected inverter. On this basis put forward a kind of current control strategy based on feed forward decoupling and SVPWM method, and introduced the principle and method of SVPWM. Then, designed the PI parameters of the current controller and analyzed the influence of the control parameters to the system control. Apply the Matlab/Simulink simulation tool to analyze the design in the above including the control strategies and the parameters. The result of the simulation analysis was to prove the feasibility and correctness of theory above, and give the reference to the actual circuit design for the next.(3) Based on the theoretical analysis and simulation, designed the hardware system based on the DSP digital control, including power circuit, IGBT drive circuit and control circuit. Draw the circuit schematic and PCB map. Build a test system of the main power circuit.(4) Gives system software design based on the DSP control, including SVPWM algorithm implementation. Coordinate transformation is presented based on the software lock-in algorithm and so on. According to the algorithm were designed corresponding to various parts of the program flow chart. Apply CCS3.3 software and C language software to programming.(5) Finally, the system developed to run on the experiment, and give the experimental results and the waveform. Verify the correctness of the proposed control theory.