Study On The Control Method Of The Grid-Connected PV Generation System

As a new type of solar energy which is clean, rich reserves, and no pollution are attracting more and more attention. Moreover the application of photovoltaic generation technology is the focus of widespread concern. This paper studies mainly on the control method of the grid-connected PV generation system. Because the price of photovoltaic cell is expensive and conversion efficiency is low presently, the control method of the grid-connected PV generation system is absolutely necessary, in order to decrease system cost and increase efficiency.The paper consists of three parts. The photovoltaic cells simulation model is established based on its output characteristic. The simulation which is the output characteristic of the solar battery under different temperature and irritation is completed using PSIM. The comparison between simulation results with the measure data proved the simulation model correct.In view of the output nonlinear of photovoltaic panels, the paper studies on the maximum power point control (MPPT) methods, and makes use of it to make photovoltaic cells work at the maximum power point, gain high-efficiency output. A boost converter is adopted to achieve maximum power point tracking. The simulation analysis and verification are realized. The work principle and control strategy of the boost converter are expounded, and the choice of circuit parameters are gave. The control circuit design process is introduced. We can see the steady-state power loss is narrowed considerably and its steady-state performance is increased from simulation and experimental results.The work principle and control strategy of the grid-connected inverter are expounded. The simulation and experiment based on the inverter control are achieved. We use hysteretic comparison tracking control method. The simulation and experiment results indicate the output factor is unit.The grid-connected PV generation experiment systems are developed. The DSP control system of the maximum power point and invert control system are designed. The results show that the use of the control strategy is feasible and effective, the main circuit and control circuits design are reasonable.