The System Of Solar Photovoltaic Grid-connected Inverter

With the rapid development of the world economics, the demands towards the sources of energy have relatively increased, also the energy shortage and environmental pollutions have stepped in. As a result, the natural source of energy like wind, solar energy gets the attention to meet the growing demand as well as reducing the environmental pollutions. The possible ways to fully utilize the natural energy sources has been the biggest concern throughout the world.The solar photovoltaic grid-connected inverter system that is studied in the article adopts two-stage structure - the former stage of DC/DC converter and the latter stage of DC/AC inverter. The former stage adopts the simple-structured and"easy-to-operate"BOOST circuit. The output voltage of the photovoltaic cells varies as the weather changes. In order to facilitate the work of the inverter, the BOOST circuit is designed to adjust the output voltage of the photovoltaic cells to an appropriate level, in accordance with the size of the grid voltage; the latter stage is a full-bridge inverter circuit, responsible for producing the current in phase with the same frequency as the grid voltage. Output current is selected as controlled variable, using digital control strategy to manage and protect the system.Secondly, the article conducted theoretical innovation on the tracing of the maximum power point and island effects. In addition, the design for the main circuit of the system and the control circuit based on DSP chip TMS320F2812 is also introduced in later part. The hardware circuit is created and debugged during the research, and the software part of the control system has undergone the programming and debugging process. The principle and structure of each circuit module is demonstrated in detail, also the design concept behind the system software and the flowchart of key parts are introduced. Finally, an experimental research is taken place based on the integration of hardware and software, and the results are analyzed. The experimental results have authenticated the effectiveness and the practicality of the design proposal.