Digital Control Of Three-phase PV Inverter

Currently, the? energy crisis and environmental problems have become the world's concern. In order to solve the increasingly serious energy crisis and environmental problems, renewable clean energy, such as solar, wind, etc., is receiving more and more attention. Solar energy, because of its huge reserves, clean and other advantages, has become the focus of people's attention. Solar photovoltaic technology and industry has been considerably researched and developed. Nowadays, solar photovoltaic energy plays an important role in our daily life, and will become one of the major energy in the future.In this dissertation, a summary about the solar PV inverter topology, inverter control techniques and its trend is given. The mathematical model of the PV inverter is analyzed, and the state space model of the PV inverter is given, with the filter inductor current and filter capacitor voltage as the state variables. The state space model of three-phase PV inverter has been further simplified through a series of transformations. On the base of system state matrix and input/output matrix, the controllability and observability of the system are studied by using matlab. By computing the controllability matrix and observability matrix, it is proved that the system is controllable and observable. Then the performance objectives of the PV inverter control system are probed. The combination of PI and repetitive control strategy is proposed, and experimental results are shown that the control strategy is effective. Based on the foregoing analysis, a DSP processor core digital control system for PV inverters is designed, and how to implement the hardware and software design of this system is illustrated. On this basis, a number of experiments are designed to verify whether this digital control system is effective in the inverter output voltage waveform control, amplitude control, frequency control and phase control. Finally, the dissertation is summarized and the direction of further research is pointed out.