Research On Closed Coal Shed Photovoltaic Power Generation System

With the progress of human society,human development of economy and culture requires a lot of energy and resources.At present,the main sources of electric energy we consume are hydropower,thermal power and nuclear power.Among them,thermal power generation is the main force of electric energy.Thermal power generation has the characteristics of relatively flexible location,effective reduction of power transmission and distribution loss,stable operation and reliable output,but its location is limited by the regional resource distribution.Photovoltaic power generation is clean and not limited by the distribution of regional resources,but its stability is relatively poor compared with thermal power units.With the advent of the 14 th five year plan,in order to accelerate China’s high-quality economic development and green and low-carbon transformation,and promote the construction of a community with a shared future for mankind,the 14 th five year plan puts forward the goal of carbon peaking and carbon neutralization.Therefore,a feasible power generation scheme integrating thermal power generation and photovoltaic power generation is urgently needed by contemporary society.In view of the current situation of thermal power generation,this paper proposes a feasible scheme to integrate thermal power generation and photovoltaic power generation.Firstly,the principle and composition of the closed coal shed photovoltaic power generation system are introduced.The closed coal shed photovoltaic power generation system is designed as a whole.Photovoltaic modules are laid above the coal shed in the thermal power plant.The photovoltaic power generation system is connected to the desulfurization system in the plant through inverter,combiner box and step-up transformer to supply power for its important auxiliary machines.Secondly,the control principle of MPPT and the principles and implementation methods of several common control algorithms are studied.Through simulation,it is found that a single control algorithm can not meet the requirements of the system for tracking speed and accuracy at the same time.Therefore,a combined control algorithm based on self seeking step size of constant voltage method is proposed.By comparing the traditional algorithm with the combined control algorithm through simulation,it is found that the new algorithm effectively improves the tracking speed and stability of the system.Applying it to the photovoltaic power generation system designed in this paper can maximize the power generation efficiency of the system.After tracking the maximum power point,in order to realize the safe and reliable grid connection of the system,in the grid connection link,the control strategy of the current loop in a commonly used voltage and current double closed-loop control mode is studied,and the current loops with different control strategies are simulated and verified by comparing the simulation results.It is confirmed that the grid connection effect of proportional resonance control is much better than proportional integral control,and its grid connection current contains less harmonic current and better power quality.Finally,the economic benefits of the project are analyzed and calculated.Through the estimation of the power generation and cost of the system within the operation life by pvsyst software,the total profit and the annual standard coal saving,carbon dioxide emission reduction and ash and slag emission reduction of the project in the operation cycle are finally calculated.