Design Of Three-phase Grid-connected PV Inverter System

In today’s world, the traditional fossil fuels are depleted, and conventional energy also cause serious environmental pollution, finding a new green energy is the only way for us. As a new green energy, solar energy cause more and more people’s attention.Photo-voltaic power generation is one of the most effective means of using solar ener gy, it will convert solar energy into electrical energy fed into the grid solar energy is non-polluting power generation, zero emissions green energy. With the rapid development of power electronic devices, photo-voltaic power generation has also been a rapid development of applications.This thesis introduce the PV power plant system, analyze the principle and the PV inverter network theory, introduce several classic MPPT algorithm and selects the disturbance observation as the thesis inverter MPPT tracking. Thesis analyzes the PWM control technology, and SPWM technology, passive islanding detection technology, low voltage ride through technology and anti-PID technology.This thesis designs the main circuit of the inverter section design, combine with 500 KW PV inverter features a detailed calculation, the completion of the main circuit IGBT type design, the DC side voltage capacitors and other devices AC side filter selection.This thesis designs control part of the PV inverter and the network carry out the work to build the control circuit section. The control section mainly use the DSP28335 core for control part to achieve the control function, SPWM drive circuit, and SPWM circuit modeling, verification and simulation by Matlab waveform analysis, and make the drive plate. Then thesis also introduce the way of the entire inverter software design, highlighting achieve SPWM program, with the realization of the program SPWM waveform introduced AD converter module program design process. The thesis also focuses on the field problems in inverter commissioning process met and propose solutions for the problem, combine with theoretical knowledge,put forward new and innovative inverter with harmonic compensation function, the new inverse change is good filtering effect, and successfully obtain a patent.Finally, this thesis summarizes the development trend of the inverter on the market, introduce a new type of string inverter.