Abstract:
Due to the growing demands of electrical energy, energy sources become the most critical issues on people's life. Recently, with the ever-increasing concerns on the global environment and fossil fuel consequences, people are focusing on development of renewable energy resources. Photovoltaic (PV) energy is one of the most promising renewable energy sources. PV simply converts sun shines into energy power. The resource of sun is both abundant and renewable. Moreover, PV does not produce any kinds of atmospheric emissions and radioactive waste. Because of no green-house gases, it will protect global climate changing, decrease carbon dioxide emission and curtail acid rain, and reduce soil damage and erosion. PV system is easy to be installed and just required little maintenance for their long lifetime. Also, it is suitable for both low power applications and large scale power plants. This thesis undertook a basic study of photovoltaic system. The aim of this research was to construct a PV system model on the Matlab-Simulink environment. The platform of Matlab-Simulink is a convenient way to simulate the PV model according to designers' requirements. Because the amount of sun energy into the PV array may change all the time, and the characteristic of current and voltage is non-linear, a maximum power point tracking (MPPT) controller is needed to keep the PV system operating at maximum power output. The circuit-based model of PV array was constructed under Matlab-Simulink environment. This model is simple and reliable. And it allows simulation of basic cells, group of cells, or mismatched panels. The simulation result of PV array shows the non-linear characteristic of PV arrays and operation of PV systems. In order to build PV system, the simple model of DC-DC boost converter was also constructed under Matlab-Simulink platform. A new innovative technology of fuzzy logic control (FLC) was described in detail in this thesis. And two maximum power point tracking controllers were built. These are perturb and observation (P&O) technique and the fuzzy logic control (FLC) algorithm. The proposed technique uses the fuzzy logic control to specify the size of incremental current in the current command of MPPT. Compared with two techniques, the simulation results show that the performance of proposed fuzzy logic control (FLC) algorithm is better than the common method of perturb and observation (P&O). The Matlab-Simulink platform developed in this thesis can serve as a very useful design and testing tool for PV system research. It can also be linked with another most useful software dSPACE, which can be utilized as an education aid. The platform can be improved in the future to cover more advanced control algorithms and full power management of the PV system.