| Energy crisis and environment pollution has aroused the attention of the worldwide. The world has actively promoted the development and utilization of green renewable energy, photovoltaic(PV)power generation has become the research hotspot as one of them. The airport has a unique advantage to develop the PV power generation. On the one hand, it can meet partial power supply of the airport.On the other, it can meet the requirements of low carbon, environmental protection, energy saving and emission reduction, which has potential application. This paper takes 115V/400 Hz off-grid PV power generation system in airport as the research object, which sets PV array and battery as the main power source and auxiliary source respectively. The system consists of PV array, Boost converter, battery,battery charging and discharging controller and inverter, in which DSP28335 is used for the control chip. This paper do some researches on maximum power point tracking(MPPT) method and control strategy of converter.Firstly, the paper analyzes the mathematical model and output characteristics of PV array. After the introduction of several common MPPT method and analysis of their advantages and disadvantages,the presented current perturbation two-phase MPPT method used in this paper is given. Which is proved in the Matlab/Simulink platform. Then, this paper introduces the composition and operational modes of the system. The two power sources(PV array and battery) coordinate to work to assure the input stable voltage of inverter for supplying power to the equipment stably and efficiently. The paper puts forward the modeling, analysis each converter, system simulation model and simulation waveform, which is used to validate the feasibility of control strategy.Finally, this paper introduces the complete design process of battery charging and discharging controller, including parameters design, sampling and processing circuits, drive circuit and auxiliary power circuit. A 500 W prototype of battery charging and discharging controller is developed, which is connected the prototype of off-grid PV inverter. The experiments for validating the theory are carried out. The results of the simulation and the experiment have conducted and approve that the designed control strategy of off-grid PV power generation system is practically correct and feasible. |
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