The Synchronizing Control And Related Research Of Microgrid With Multiple Distributed Generators

Due to the wide application of distributed generation technology, microgrid has been rapidly developed. The coordination control of distributed power supply and smooth synchronizing control strategy are the key in the process of synchronizing with the main grid.Paper based on the analysis of distributed generators and microgrid structure and characteristics, researches on distributed power control method, microgrid operation control strategy, and voltage and frequency support of microgrid system subjected to disturbance, putting forward a kind of the synchronizing control method based on grid-connected signal prediction. The method reduces amplitiude difference, phase difference and frequency in the synchronous switching, finishing the smooth transition from islanding operation pattern to the grid-connected pattern. The simulation results verify the effectiveness of the control algorithm.The main work is as follow:First, the paper analysizes the working principle and operation characteristics of each distributed power supply unit and studies the voltage, frequency and power characteristics of distributed power supply with environment factor changes and load changes within the Matlab simulation.Secondly, the paper builds a model of microgrid with multiple distributed generators, researches the frequency and voltage support of microgrid after disturbance, and adopts a coordination control method with improved droop control and PQ control. In the simulation model of microgrid islanding with load switching and operating status change, the impact on the frequency and voltage stability of the microgrid system shows that the proposed coordinated control strategy is correct.Thirdly, the paper introduces the different operating characteristics of microgrid in grid-connected and islanding modes, and studies its smooth switching between two kinds of operating modes. For islanded microgrid switching to the grid-connected mode, the paper proposes synchronizing control method based on Kalman filter estimation, and optimizes synchronization signals forecast to realize islanded microgrid change to grid-connected mode smoothly.