Research And Development On Central Stabilization Controller Of Micro-Grid System For Isolated Islands

With the increasing serious problems of social environmental pollution and energy shortage in recent years,the micro-grids which use distributed generation technologies have been attached more importance.For an area which cannot be covered by large grids such as micro islands or remote mountain areas,the island micro-grid is one of the best solutions for residents to provide electricity supply.In this paper,a design of island micro-grid central stability controller is given and this paper also gives a solution of coordinated control strategy based on wind power,solar power,energy storage and diesel power.It can be effectively applied to control systems of island micro-grid.This paper first studies the related distributed generation technology and the structure of micro-grid and then proposes architecture of the micro-grid.On this basis,a solution of island micro-grid coordinated control strategy is proposed.The strategy includes a method for rapid assessment of distributed generation equipment and loads in the grid,a frequency control method based on dynamic load shedding,a voltage control method based on fuzzy PID and a battery optimization control method based on frequency and voltage steady state.The method of frequency control strategy based on dynamic load shedding takes the economic performance into consider and takes the diesel generators as a constant power and non-economic distributed power discussed in every sub-strategies one by one.The fuzzy PID-based voltage control strategy improves the traditional PID to a fuzzy PID control and improves system stability.In battery optimization control strategy,three sub-strategies of charge control,discharge control and energy balance control are given,which make the battery have better economic performance under the fixed charge and discharge life.The strategy can control the voltage stability and the frequency stability of the island micro-grid and it can optimize the energy balance of the island micro-grid.This paper shows a detailed hardware design and software design of the island micro-grid stable central controller and shows the hardware design and software design of the load measurement protection unit which is supporting for the central controller.The island micro-grid stable central controller fully considers the actual application environment of the island and the current power electronic equipment communication interface and retains a series of feature-rich interfaces in order to control the equipment of island micro-grid At the end of the article,an island micro-grid project based on resident and fishery production and living electricity utilization of Weihai Xiaoshi Island is proposed.Based on this project,an island micro-grid experimental model is built in proportion.The control strategy and the island micro-grid stable central controller given by this paper are tested on the experimental model.The test result is very satisfactory and the power quality meets the GB/T 12325 and GB/T 15945 national standard.This paper is of great significant for the practical popularization of island micro-grids.