| The development and utilization of energy is closely related to the protection of the environment.In recent years,some new types of energy have been paid more and more attention.Solar energy is rich in reserve and green pollution-free,which has made it become an ideal alternative energy,at the same time,the energy can be easily used by connecting grid conveniently.Improving the efficiency of solar grid connected power generation is taken as the core and the key technologies of the inverter and the input side of the inverter are studied in this paper.In this paper,the mathematical model of photovoltaic cells is established,and the relationship between the characteristic curve of photovoltaic cells and the maximum power point and the light intensity and temperature is analyzed.Traditional MPPT algorithm and intelligent fuzzy control MPPT algorithm are analyzed in detail.A combination of coordinate transformation,fuzzy control and the traditional algorithm is proposed,improving the traditional MPPT algorithm and the algorithm has the advantages of high precision,fast response and easy implementation of hardware circuit.Secondly,the principle of BOOST chopper circuit is analyzed,and a mathematical model is established.In order to improve the robustness of the chopper,a double closed-loop control structure is adopted in this paper.Nonlinear PI control unit and auto disturbance rejection device are used in each closed-loop structure,which can improve the robust performance of the system.At last,the working principle of T-type three level grid connected inverter is analyzed and a mathematical model is established.Besides,the experimental platform of photovoltaic grid connected power generation system is established by using current closed-loop vector control strategy.In order to realize the control of the inverter,a new method of dead time compensation is adopted in this paper,reducing the harmonic content of the output current.Simulation results show that the method is effective. |
PDF Full Text Request