Research On Coordination Control And Optimization Of Distributed Generators In Micro-grid

Micro-grid could improve the efficiency of distributed generation. So it has become the research hotspot and key development direction of distributed generation research field. In this paper, the coordination control strategy of distributed generators in micro-grid was studied, and an improved droop control strategy was proposed for improving the distribution accuracy of reactive power. Then, the coordinated control of micro-grid was optimized by the improved harmony search algorithm based on PSO(Particle Swarm Optimization-Improved Harmony Search Algorithm, PSO-IHS). The main research contents are as follows:(1) The mathematical models of distributed generators in micro-grid were established. Control strategies of distributed generators were analyzed. Theirs simulation models in simulink were built, and simulation analysis was carried out.(2) The full order small signal dynamic model of micro-grid was established. The system stability of the micro-grid and the influence of the droop coefficient variation on system stability were analyzed Based on eigenvalue analysis. Then the simulation model of micro-grid in simulink was built. Simulation analysis was carried out when micro-grid was operating on four operation modes(autonomous operation, Load mutation on islanded operation, grid-connected operation, operation modes switched between autonomous operation and grid-connected operation).(3) The simulation analysis of microgrid showed that the reactive power allocation was not according to reactive power droop coefficient. So the reactive droop control strategy was improved and the simulation was carried out. The effectiveness of improvement was verified by compared with before improvement.(4) The micro-grid dynamic switching model Based on PSO-IHS was established. And the control objective function of micro-grid running on four operating modes(autonomous operation, Load mutation on islanded operation, grid-connected operation, operation modes switched between autonomous operation and grid-connected operation) was established. Then, the objective function was optimized by PSO-IHS to improve the stability and dynamic performance of micro-grid in these four operating modes.(5) The micro-grid coordinated control system was built based on the RT-LAB real-time simulation platform. The real time simulation analysis of micro-grid was carried out, and the system stability was verified.