Research Of Single-phase Photovoltaic Grid Inverter

With the rapid development of modern society economy, energy exhaustion, environment pollution and ecological destruction problem become more and more serious. How to balance between economic development and energy crisis now has become the focus attention of people and the most sensitive topic. The green life idea of "energy conservation and emission reduction","low carbon" presented in the Copenhagen conference has penetrated popular’s feeling. The direction of global economy development and navigation standard has turned to the low carbon economy. Oil, natural gas, coal and other traditional energy are increasingly exhausted, in the long-term development run, human society has to turn to research the new renewable energy. As one kind of new renewable clean energy, solar energy is inexhaustible, efficient use of solar energy is the favour of the world. Based on this, as the key technology of solar energy utilization, photovoltaic energy arises at the historic moment and is valued and developed by varieties of courties. This paper researches the single-phase PV power inverter system.This paper firstly introduces the background and significance of photovoltaic power generation, analyses the present research situation and development trend of domestic and international photovoltaic energy power, introduces photovoltaic power system composition and classification. And then studies topological structure of grid inverter system, select the bipolar energy grid inverter system. DC/DC chopper circuit and the choice of inverter circuits are analyzed, and choose Boost circuit for the former stage, the whole bridge for inverter and no transformer isolation grid method. Photovoltaic grid inverter mathematical model is built.Control strategy is adopted in the former of the voltage as outer ring and the current as inner ring, Then compare several SPWM modulation mode and control technology, and choose the dual polarity modulation mode and symmetric rules sampling method. Then introduces the work principle of photovoltaic cells and engineering mathematical model, compare several maximum power point tracking MPPT principle and characteristics, and presents the corresponding flow chart.On the basis, design he hardware platform of the photovoltaic grid inverter system in the center of TMS320F2812controller, the selection of the instruments, parameter design and detection circuit of inverter circuits part are analysed,presents the main module’s software realization process. Finally, engineering model of photovoltaic cells and output characteristics are simulated under the condition of Simulink, as well as the SPWM wave and the grid inverter system,verifing the correctness and rationality of the theory.