Simulation And Research Of Technology In PV-connected System Based On DSP

Traditional fuels reduce day by day, harmful to the environment worsening, at the same, there are about 20 billion people don't have normal energy supply all over the world. Then, people cast their eyes on renewable energy; hope renewable energy can change our energy structure, and maintain long-term sustainable development. Solar energy is abundantly, widely distributed, revertible, does not pollute the environment, it is recognized as the ideal alternative energy source. PV power generation has been growing attention to the countries because its advantages and characteristics. PV grid-connected system is an important direction of PV power generation. PV grid-connected inverter is the core component in PV grid-connected system. This thesis read as follows:This thesis provide an overview of the background, significance, status, development problems and prospects of photovoltaic technology,and introduce the structure and classification of the grid-connected PV system simply. Hold a comprehensive comprehension of grid-connected PV system.Discuss the working principle, Volt-ampere characteristics and output power of photovoltaic cells, provide a theoretical foundation to practical application.Photovoltaic array is a nonlinear power. Maximum power point tracking control (MPPT) is a problem often encountered in grid-connected PV system, the thesis analysis and compare some MPPT designs used frequently, provide the use of optimal gradient method to track the maximum power point, make a satisfied result, and algorithm is simple.Grid-connected PV system is consisted of PV array, converter and controller, controller is the core technology. It adopts two-level inverter topology in the thesis. The thesis focus on the design of the DC-DC converter, DC-AC inverter, and controller based on DSP and protection circuit, analyze the working principle of these circuits, determining the appropriate parameters and electronic devices. Using MATLAB/SIMULINK to establish an inverter, it can change voltage form DC 138V to AC 220, the simulation verify the feasibility and reliability of the design.By comparison, adopt current control mode to PV grid-connected inverter as reasonable theory. Using MATLAB / SIMULINK to establish a mode to track current based on digital control strategy, determining the appropriate parameters, simulation, verifying design of the control strategy of this article by tests.