Research On The Operating Characteristics Of Microgrid And Its Integrated Control Method

Distributed generation to find a breakthrough to solve the shortcomings of thecurrent centralized power generation and renewable energy generation and network,but the intended load characteristics of distributed generation access system has manydeficiencies. In order to coordinate the contradiction between the grid and distributedpower supply, many scholars have proposed the concept of microgrid. Microgridoffers the possibility for large-scale distributed power connected to the grid, and it runthe networking and the island state. The microgrid interconnection absorb or suppl ofenergy from the main network, and when the main network failure, the microgrid fromthe main network to enter the island running state. In order to maintain the islandoperation of the microgrid, we need to integrated control between the micro-powerand energy storage.The core issue of the microgrid is the control problem. In this paper, it studies theintegrated control strategy for the modeling and simulation of microgrid. Core work isconcentrated in three areas: master-slave control strategy of microgrid and itsoperating characteristics analysis, control system design of distributed powerinverters in microgrid, the impact of the microgrid to grid.First of all, the article describes the significance of microgrid background andcurrent development at home and abroad, and described in detail coordination controltheory of micro-power and its applicability in the microgrid. Secondly, the paperstudied inverter control theory in the microgrid, and illustrated the control structure ofthe inverter and inverter basic control strategy in the microgrid, and understund themathematical model of the inverter and SVPWM technology principle and realizationmethod. Again, this paper proposes a PQ Control Strategy Inverter System based on acontrol of both power and electrical current and its operating characteristics wereanalyzed, but the controller is composed by the power control outer loop and currentcontrol inner. Through a numerical example, Inverter output voltage is stable, activeand reactive power decoupling operations can be achieved, and to improve the qualityof output current and control the trend of average power. Then, the paper designedbased on the improved droop characteristics of the V/f controller and its operatingcharacteristics were analyzed. Through a numerical example, distributed powercontrollers is able to self-sensing frequency and voltage fluctuations of microgrid to automatically adjust without communication, and the voltage and current loop hasfeatures with the appropriate speed, high accuracy and improve power quality. Finally,desgined of a V/f control strategy as the main controller and construct of a PQ controlstrategy inverter system as slave the controller. And then, put forward a master-slavecontrol strategy of the coordinated control strategy of the microgrid between varioustypes of distributed power supply without data correspondence. With the coordinatedcontrol, the improvement in the availability of uncertainty of energy resources whichcause distributed power supply join in the frequency adjustment of the microgrid isderived. At last the correctness and validity of this coordinated control strategy isverified by converting the microgrid between the island model and grid-connectedmode, this paper imitating and emulating of the varying characters with voltage andfrequency under the transient operation of the island model.