Photovoltaic Inverter Single Stage Research For Intelligent Micro-grid

As the global energy and environmental problems become increasingly prominent, renewable energy has gained wide attention and development, including wind power, tidal power, solar photovoltaic power generation. Solar photovoltaic power generation is an effective means to make full use of solar energy with great development prospect. Most of the renewable energy is connected into grid by distributed generation technology. With a large number of distributed power connecting into grid, a lot of adverse impact is brought into the grid. It becomes a bottleneck for the development of renewable energy. Intelligent micro-grid technology is the key of resolving the problem.At present, the intelligent micro-grid becomes a research hotspot. The concept of the intelligent micro-grid hasn’t unified. To this paper, the intelligent micro-grid is micro-grid with intelligence, which can be flexibly connected or disco nnected to the grid. Intelligent micro-grid is compatible, stable, flexible, economic and with other characteristics. The development of intelligent micro-grid can promote the development of renewable energy effectively, while new requirements are put forward to renewable energy technologies by intelligent micro-grid.First this paper declares the opinion that intelligent micro-grid is the future development trend of power grid, which can provide higher reliability, make the maximum use of clean energy and promote technology innovation. With the respect of the complexity and limitation of the establishment of micro-grid experimental architecture, this paper focuses on the photovoltaic inverter. Photovoltaic inverter based on intelligent micro-grid can flexibly work in grid-connected mode and stand-alone mode according to the control requirements. This paper introduces the related principle. Single-stage inverter topology has been adopted in photovoltaic inverter. One-cycle control method combines with the perturbation and observation method is used to achieve photovoltaic maximum power point tracking. And single cycle control and maximum power point tracking model are studied and discussed deeply.Then the models of grid-connected and off-grid are established in PSIM simulation environment, the control and design method are introduced based on analyzing the control principle. The effectiveness and reliability of the model are demonstrated by the simulation model. Finally, considering the compatible and economy requirements of intelligent micro-grid, ARM Cortex-M3series processor is adopted in this paper. This processor has perfect functions, strong compatibility, with the character of economic, reliable and easy development. The specific hardware design of the single-stage photovoltaic inverter system based on ARM series Cortex-M3controller is presented in this paper, and the control program development, the control flow-chart too. Then the system runs in off-line and grid-connected mode with the requirements of intelligent micro-grid, the result shows that the single-stage photovoltaic inverter system runs stably, meets the design requirement.