Research On Coordinated Control Method Of Distributed Resources In Microgrid

New energy and renewable energy generation is generally recognized an important way to solve environmental pollution and energy shortages.However,the operation of grid-connected distributed generations of these forms poses serious challenges to the security and stability of the power grid,so microgrid technology emerges as the times require.Microgrid provides an effective technical means for the large-scale applications of new and renewable energy.Distributed generations can be well coordinated and effectively managed via microgrid technology,which supports “plug and play” and efficient and flexible use of distributed distributions,meets the users' personalized energy demand and and is in line with China's development requirements of distributed generations,which require sustainable development and adaption to local conditions.With the development of microgrid technology,the coordination control of distributed generations,the optimization and coordination control of microgrid system energy and the application of microgrid technology in active distribution network need urgent and in-depth study,so this paper studies from the perspective of microgrid control to give full play to the advantages of the effective use of distributed generations in microgrid.Firstly,this paper systematically introduces the types of distributed generations and energy storage devices,the whole control tactics of microgrid and the control strategy of distributed power inverter,and also analyses parallel controls of distributed power inverter with no interconnections;Secondly,considering about the deficiencies of traditional droop control,this paper proposes P-f/Q-dU/ dt' 'improved droop control method to overcome the effects of line parameters on microgrid power distribution,achieve reasonable power distribution and improve power quality in microgrid.On the basis of the P-f/Q-dU/ dt' 'improved droop control method,a mathematical model of microgrid is established.Based on part of the output feedback optimization and decentralized coordination control in combination with the proposed improved droop control method,this paper proposes optimization and decentralized coordination control method to improve microgrid system dynamic performance and achieve better overall operating performance.The simulations of different working conditions are done to verify the correctness and feasibility of the proposed method.Then,a multiple complementary structure of new energy and energy optimization strategies in microgrid are introduced.This paper proposes the coordination control strategy of distributed generations and various energy storage devices to solve the problem of power balance and energy optimization and coordination control.The time constant of a low-pass filter is adjusted by the state of charge of the energy storage devices to stabilize powerfluctuations at different time scales,which gives full play to the advantages of distributed generations and energy storage devices to meet the power balance in microgrid.Finally,this paper innovatively puts forward a technical scheme of the application of microgrid technology in active distribution network.We study the active distribution network and microgrid group,elaborate the grid structure,planning and design,control strategy,operating mode,and comprehensive benefits fo the connection of the microgrid group to the active distribution network.We analyze the benefits that the application of microgrid technology brings to the active distribution network and also indicates the research direction needed exploring.