The Study Of Photovoltaic Grid-connected Power Generation System

With energy and environmental issues have become increasingly prominent,solar energy as a renewable clean energy is attention by more and more countries,solar energy in the world already has a pivotal position.Compared to small scale off-grid power systems,power generation systems play the advantages of solar energy inexhaustible better,the use of solar power generation will be more and more used in our actual life in the future.Through the analysis of the output characteristics of the photovoltaic cell,establish a mathematical model of the project photovoltaic cell array,and verified the correctness of the established mathematical model;comparison of several maximum power point tracking method through research and analysis.This paper determined conductance increment method to achieve the photovoltaic cell maximum power point tracking.Through the analysis and study of pre-DC/DC converter several topologies of the two-stage grid-connected photovoltaic systems.For the problem of power conversion efficiency,this paper designed a DC bus,modular DC/DC system,the modular system consists of two parts battery charging module and flyback DC/DC module.The modular structure made the designed module composition become relatively flexible,according to the system requirements,either a single sub-module used independently or in combination,while providing the flexibility to adapt the system to the inverter DC bus voltage or constant voltage requirements,made the choice of control of the inverter system is more flexible.Through SIMULINK modeling the design of modular DC/DC system simulation,designed hardware circuit and software control.Experimental results showed that the proposed modular DC/DC strulcture compared to the conventional configuration has improved energy conversion efficiencyThis paper studied on the principle and control technology of photovoltaic grid inverter,used voltage-current double closed loop PI control,designed photovoltaic grid-connected inverter structure,modeled and simulated the designed inverter,verified the feasibility of the designed photovoltaic grid inverter.