Study Of Master-slave Control Strategy In The Isolated Microgrid

With the increasingly fossil energy depletion and environmental protection needs, furthermore, power supplying simply relying on the big power grid will bring security flaws, distributed generator used clean energy technologies are increasingly attracting attention.Microgrid is a low-voltage power grid combines small distributed source and energy storage devices together to provide power for the local load.And it is the major operation mode of distributed source in the future.Microgrid has two operation modes, network and islanded, it can improve supply reliability of the important load.Islanding operation is the important features of microgrid, is strong guarantee of improving the power supply reliability of the important loads in microgrid. When an isolated microgrid runs, the essential problem needed to solve is to implement the coordination between multiple distributed power control. In this paper, master-slave control strategy is proposed, the V/f control method is used in master distributed power to provide a stable voltage and frequency for the microgrid; P-Q control method is applied in the slaves, making full use of renewable energy. With this control strategy,the isolated microgrid can run with good steady and dynamic performance. The main work of this articleis as follows:1. The paper describes the working principle of SPWM voltage source inverter, establishes V/f, PQ simulation model in MATLAB/Simulink environment and researches the run characteristics of controller.2. The paper establishes photovoltaic battery mathematical model and the simulation model photovoltaic battery with MPPT, finally accesses PQ inverter controller and researches the corresponding operation characteristic.3. The paper analysis the basic principle of asynchronous wind turbine, establishes simulation model of wind power generation systems according to air dynamics knowledge, then designs rectifier controller and establishes corresponding simulation model, finally accesses V/f inverter controller and researches the corresponding operation characteristic. 4. The paper analysis the islanding operation characteristic in microgrid, establishes simulation platform of microgrid islanding in ideal state, and analyzes the corresponding operation characteristic.Work carried out in this paper provides good reference value for islanding operation.