Research On VSG Control Strategy Of Grid-connected Inverter Based On Power Internet Of Things

Today in the 21 st century,global problems such as energy depletion and ecological pollution have become increasingly serious.In this context,new energy power generation is cleaner and sustainable,so grid-connected inverters,as the energy exchange interface between the grid and new energy power generation,have received great attention from all walks of life.However,due to the small inertia and damping of the grid-connected inverter composed of power electronic devices,when its proportion in the power system increases,the inertia and damping of the large power grid will inevitably be affected by it,and it may even be vulnerable to load fluctuations causing instability.Virtual Synchronous Generator(VSG)control is carried out for grid-connected inverters in the microgrid.It achieves the purpose of enhancing the dynamic stability of large-scale new energy grid-connected by adjusting the virtual inertia and damping of the inverter.At the same time,with the vigorous development of the Internet of Things technology,the power system is also seeking an informatization development path.The Power Internet of Things technology can obtain real-time information of grid-connected power sources and loads in the power grid to achieve coordinated dispatch,and it plans and distributes the given power of each distributed power source in real time to ensure the static stability of the source and load.Combining Power Internet of Things technology with VSG control can significantly improve the stability of new energy grid connection.Based on this,this paper takes photovoltaic grid-connected as an example,and does related research on the VSG control strategy of three-phase grid-connected inverter and the Power Internet of Things communication scheme in it.The main research contents include:1.In order to improve the dynamic stability of large-scale grid-connected new energy,the conventional control strategy of the three-phase grid-connected inverter system is studied,and a VSG control scheme with PI current inner loop and PQ power outer loop is proposed.This scheme uses the power electronic converter to adjust the inertia and damping of the microgrid,which improves the dynamic stability of the microgrid.The system structure of a 10kW prototype was designed,and the effectiveness of the scheme was verified by the simulation of the prototype.2.Aiming at the communication between the power equipment and the multi-layer control structure of the grid-connected inverter,it realizes the remote dispatch of new energy power generation and ensures the static stability of the source and the load.Based on the analysis of the Internet of Things technology and related theories,this paper proposes a Power Internet of Things structure based on the LoRa wireless network.The structure is simple and reliable,and it is easy to modify existing equipment to realize networking.3.Combined with dsPIC microcontroller hardware debugging and software development,Internet of Things equipment and 10kW grid-connected inverter prototype,the network and communication of the proposed Power Internet of Things structure are simply built.The remote grid-connected power adjustment experiment was carried out on the inverter prototype using the Power Internet of Things technology.The experimental results of the prototype verified the feasibility and effectiveness of the scheme.This plays a positive role in further promoting the construction of smart grids,and also has a theoretical guiding role in the stability of new energy grids.