A Research On The Central Monitoring System Of Multi VSG Micro Grid Test Bed

Distributed generation and micro grid technology are an important stage for the transition from traditional grid to smart grid. As an important power electronic device connecting the distributed generation to the large power grid, the control strategy of the inverter is various, while it is very important. The monitoring of micro grid operation state is not only the premise of micro grid stability, safety analysis, energy management,it can also be used to evaluate the control strategy and help researchers to improve and optimize the control strategy. Based on the analysis of research status of microgrid control strategy and control system and time synchronization technology, this thesis clarified the research significance and the design goal of this thesis, which is to design a set of test bench design inverter based on VSG control strategy, and it can monitor the operation conditions of the test-bed. The main works are as follows:Firstly, this thesis introduces the basic principle of the Virtual Synchronous Generator (VSG), then the mathematical model of three-phase inverter and synchronous generator are analyzed. On this basis, a VSG control strategy is designed, and the design method of VSG governor and VSG excitation regulator is given, and the simulation model is built by Simulink. The simulation results show that the inverter with VSG control strategy has the output characteristics of synchronous generator.Secondly, considering synchronous data sampling and phase measurement for the micro grid stability analysis and monitoring the running state of the inverter, this thesis designs a set of high precision timing module based on GPS tame OCXO technology.The design method of hardware circuit and the software flow diagram are given. This module can output 10MHz clock signal, 1PPS Local signal and GPS serial port data, its main function is to make the synchronous sampling and the time label of the inverter.Thirdly, this thesis designs a set of inverter test bench and host computer monitoring system based on LabVIEW, and gives the hardware circuit design, the software flow diagram of the lower computer and the software flow diagram of the monitoring system. In addition to verifying the design of the virtual synchronous generator (VSG) algorithm, the experimental platform can also send the voltage, current,control parameters and other data to the host computer monitoring system. The PC monitoring system can not only analysis the inverter voltage / current RMS, active power and reactive power, harmonic, three-phase unbalance state in real time, but also can store and query on data.Finally, the sixth chapter gives the result of the test result of high precision time synchronization module, inverter experiment and computer monitoring system.