Distributed Photovoltaic Power Supply For AC Flexible Transmission Research

In recent years,the lack of energy and the shortage of resources have received worldwide attention.These problems are more serious in China.The traditional thermal power generation method not only pollutes the environment,but also the coal used is a non-renewable resource that pollutes the environment,and the shortage of coal resources is becoming increasingly serious.Therefore,people are now using new energy more and more,and distributed photovoltaic power generation can effectively solve the above problems,and it has the advantages of wide distribution,environmental friendliness and energy richness.Distributed photovoltaic power generation has received attention from all over the world.Because the output power of photovoltaic power generation is unstable,it is affected by natural conditions such as season,sunshine time,rain and snow,etc.,so it will show instability and discontinuity,which will cause output.The power is unstable,so the maximum power tracking technology needs to be used.The purpose is to provide a stable output power for the system to ensure the stability of the system when the external environment changes.The distributed photovoltaic power source is applied to the AC flexible power transmission to adjust the line power flow and compensate the active reactive power in the system.Eventually,the voltage amplitude,phase and frequency of the line before the grid connection are consistent with those in the large power grid.In this paper,the maximum power tracking technology used in distributed photovoltaic power supply is analyzed and introduced.The maximum power tracking point is found by the conductance increment method.The DC-DC transform is performed according to the boost chopping technology.The maximum power point algorithm is found through simulation verification.The plausibility and Boost chopping voltage control achieve the effectiveness of load current matching with maximum power tracking.Then the mathematical model of the grid-connected inverter and the grid inverter is established,and the corresponding controller is designed.Finally,the two are combined to form a back-to-back inverter power string-grid control system,which is unified.The power flow controller(UPFC)control device adjusts the system power flow.The parallel converter uses a dual-loop PI decoupling control strategy.The series converter uses a dual-loop control based on the series converter output voltage and the output filter inductor current.Finally,the feasibility of the control strategy is illustrated by simulation verification.Finally,the requirements for grid connection are met and connected to the grid.