Control Device Development Of User-Side Microgrid

As an effective management form of distributed energy,smart microgrid plays an important role in the local consumption of distributed energy.For different types of users,research on practical protection and control technology of the microgrid on the user side and development of low-cost control device are both key links to guarantee the promotion and application of user-side microgrid.In the initial stage of microgrid development,we usually focus on key technology research related with planning and design,control,operation and equipment development.And carry out the feasible validation of key technologies and equipment through demonstration projects.However,there are still two issues unsolved in the past research projects and practical work.On the one hand,the attention of users’ needs is not enough.With the large-scale access of the distributed PV generation system on the user side,the possibility of a typical user-side microgrid formed in home,building and community greatly increases,and users’ needs differ with different region,environment and economy.Thus the applicability of related key technologies and equipments are still insufficient.On the other hand,we care too less about the input-output economic benefits and the value of follow-up application of attention.In order to complete the demonstration project,a lot of manpower and resources is put,but the benefits and promotion value are very limited,which is difficult to be accepted by users.Therefore,it is very necessary to develop low-cost microgrid central controller covering key technologies of microgrid access,which provides low-cost,high-efficiency solution for user-side microgrid and promotes its large-scale development.Therefore,the research on the microgrid central controller of user-side microgrid is carried out.The main contents are as follows.Firstly,this paper researched on the topology,capacity configuration,networking and application scenarios of different types of user-side microgrids,such as residential users,business users and industrial users.The overall quantitative analysis and design of the user-side microgrid central controller was analyzed from three aspects: functional location,performance objectives and hardware requirements.On this basis,the overall hardware and software framework of the device was given.Secondly,based on the study of system topology,characteristics of component unit,communication methods and conditions of user-side micro-grid,the central control algorithm is designed and simulated for the user-side microgrid,and the control algorithm can be ap-plied to all users Side micro-grid scene and operating conditions.Thirdly,the hardware design of microgrid central controller was proposed.The hardware design included the functional module design,electrical design and structural design.In order to meet the multi-object and multi-level communication requirements of the user-side microgrid,the terminal communication module and underlying device communication module are were designed.The man-machine interface module was set up to enhance the human-computer interaction.What’s more,in order to ensure the security and reliability of data storage,we set up a data storage module.The electrical design provided the controller’s system topology and main module board design.As for structural design,this paper fully considered the device appearance,internal layout,Lead-in Line pattern,mechanical installation and other factors,and took the maximize compatibility,the most compact size and the most reasonable layout as the final design goals.Thirdly,the software design of microgrid central controller was proposed.It involved distributed PV generation forecasting,load forecasting,multi-islanding detection,black start,on/off-grid operation,on/off-grid switching,fault protection and other microgrid control functions.And through offline simulation,the designed control strategy could achieve millisecond system control,minute-level real-time optimized operation and hourly optimized scheduling and management.Fourthly,we built a testing platform of single/three-phase hybrid two-layer microgrid,and tested the software functions of the controller online to evaluate its stability and reliability.Through the test,all items detected meet the requirements of testing principles.