The Optical-storage Microgrid System And Operation Control

Microgrid is coposed of distributed generations, energy storage devices, loads and the control system, containing the grid-connected model and the islanded model. Under normal circumstances, the microgrid together with conventional distribution grid network operation, when the dected power grid fault or power quality can not meet the operation requirements, microgrid disconnect from the grid, transferring into the islanded operation model, which can increase the reliabity of power supply for the important load.To realize the coordinated control of multiple distributed generations under the grid-connected model and the islanded model in the microgrid, this paper studies the master-slave control and the peer-to-peer control. All the distributed generations adopt Droop control method in the peer-to-peer control strategies. In the master-slave control strategies, to realize the distributed generations energy supply used sufficiently and reasonably, all the distributed generations adopt PQ control method under the the grid-connected model, supporting the voltage and frequency by the grid. Under the islanded model, V/f control method is applied in master distributed generations to provide stable voltage and frequency for the microgrid, PQ control method is employed in the slaves, making full use of energy provided by the renewable energy. Those effective control strategies make the microgrid can work with good steady and dynamic function. In the paper, the main work as follows:1. This paper describes the working principle of distributed generation’s SPWM inverter, analyses the working principle of Droop, V/f, PQ based on the SPWM inverter and researches the operation characteristics of various kinds of controllers.2. This paper established photovoltric cell mathematical model based on analyzing the the working principle of the photovoltric cell, then the simulation showed that the output characteristics of the photovoltaic cell is asymmetric and strong nonlinear. Useing the asymmetric fuzzy control strategy based on P&O to achieve MPPT to improve the efficiency of photovoltric energy conversion, which is compelled with the conventional P&O, and finally researches the corresponding run characteristics.3. This paper firstly carried out simulation to verify the operation characteristics of the PQ control and V/f control in the master-slave control strategies, then building the operation model of the microgrid based on the master-slave control strategies. The photovoltaic is slaved distributed generation, using the asymmetric fuzzy control to realize the maximum power point tracking and grid-connect. The simulation show that the output characteristics of voltage, current, frequency, load and kinds of DG, researching the corresponding operation characteristic.4. This paper builds the operation model of the microgrid based on the peer-to-peer control strategies using Droop method, analyses the load changes mode and the DG changes mode in islanding as well as the switch mode between the grid-connected operation and the islanding operation, studies the changing laws of the bus voltage, power and frequency of the microgrid.