Solar Photovoltaic Power Generation System

The reverse of fossil fuel is decreasing day and day . At the same time, awareness of the importance of protecting the global environment is growing. So searching for pollution-free replacer of fossil resources becomes more and more urgent. Photovoltaic source as Renewable energy is pollution-free and inexhaustible. So photovoltaic generation technology was got more and more attention. With price reduction of PV modules and development of PV technology, the role of PV generation systems is gradually changed from supplemental energy to substitute energy. This thesis presents the configuration, the operation principle and the design procedure of a low power photovoltaic inverter connected with electric utility lines, and deals with such key problems as true maximum power point tracking (MPPT) of PV array and improvement of inverter output wave, islanding effect and so on by establishing related simulation models, applying novel control strategies and experiments validation .The main contents of the paper are as follows :1. Introducing the actuality and foreground of PV sources abroad or our country. The basic structure and types of the PV source also are presented. Holding apprehend in the mass to the system.2. This paper has studied on the basic principle and output characters of PV cell. The emphasis is on the output characters and its effect factor.3. The output of PV is non-linear, which has Maximum power point tracking(MPPT) problem. This paper has studied MPPT method, and proposed improved measures . The method of tracing the maximum PV powered points is realized with a boost converter in this design. The circuit is experimented by the emulator PSIM at last. And then the thesis explains the operation principle and control strategy of boost converter. And component's parameters of the main circuit are introduced, the design procedure of the control circuit is given. The boost converter is controlled by a core P89LPC938 and TL494. 4. The operational principles of photovoltaic grid-connected generation system were analyzed. The topology structure of the inverter section is single-phase full bridge, the thesis presents the operation principle, control strategy, hardware and software design. The control method is hysteresis tracking method. The DC-AC inverter is controlled by DSP TMS320LF2407.The islanding phenomenon of grid-connected PV system is discussed, which harm and detection methods are investigated. In this paper, proposed islanding detection method .Simulation results verified that method using PSIM.