Research On Multi-energy Complement And Coordinated Control Of Microgrid

Currently, Centralized power generation and Long-distance transmission is the mainform of power system in our country. With the concept of Low-carbon economy and smartgrid, distributed generation which is closed to user side is getting more and more attention.Distributed generation can make full use of clean energy, such as wind and solar power. Sincethe fluctuations of clean energy generation output, it will bring some problems whenconnecting to power grid. Microgrid is an effective way to solve the problems of distributedgeneration connecting to power grid. Microgrid can operate in grid connect mode andislanded mode. At grid connect mode, microgrid can be treated as equivalent load or powerbased on its energy fluidity. The multi distributed generations and operation modes make thecontrol strategies of microgrid more complex. This paper mainly studied the control strategiesfor microgrid to maintain energy balance and frequency and voltage stability under conditionsof multi distributed generations and operation modes.Firstly, this paper analyzed the species and control strategies of distributed resources andthe total control strategy of microgrid. When emphasizing at the use of power electronicinterface, this paper also describes the control features of different distributed resources. Thecontrol of distributed resources is the basis, hierarchical control is the main form of microgrid.Secondly, this paper proposed multi energy complementary and voltage and frequencyregulation control strategies. For wind power and energy storage, comparing with currentresearch, a new control strategy is designed to stable total power output of multi distributedgenerations. For voltage and frequency regulation problems of microgrid, this paper proposedcorresponding control strategies. A dynamic voltage control strategy is proposed to meet therequirement from recent grid code and low voltage ride through. This strategy makes use ofpower electronic interface and supply voltage to support grid voltage during fault. Forfrequency regulation during islanded operation of microgrid, hierarchical frequency controlstrategy was proposed. Battery with static error regulation, microturbine without static errorand microgrid central control is realized respectly.Finally, simulation model of microgrid with multi distributed generations is established in DIgSILENT software. The simulation results verified the validity of proposed controlstrategies.