Research On Parallel Control Strategies Of Inverters For Microgrid

The development of Distributed Generation technology has been driven by the highlighted environmental problems and the aggravated energy crisis.Microgrid is the link between distributed resources and the main grid.Inverters are very improtant for microgrid as its key equipments.This paper has focused on the research of parallel inverters' power decoupling and power distribution problems in microgrid.Firstly,this paper has introduced the backgroud information of the research question and the current microgrid power decoupling as well as paralle inverters' power distribution control strategies.Secondly,three phase inverters' mathematical models and control strategies have been given briefly.This paper has presented power decoupling and power distribution problems of parallel inverters operated in autonomous mode in detail in Chapter three and Chapter four.In chapter three,virtual power droop control method based on coordinate transformation has been utilized.Relative gain analysis method has been used to analyze its decoupling effectiveness.Besides,improved power distribution control strategy has been proposed.Novel virtual power restriction control method has been proposed to ensure that each inverter could operate in its safe operating range.In chapter four,aimed at parallel inverters' power distribution problems,a power distribution strategy based on dynamic consensus has been proposed.Each micro source will communicate with some of its adjacent ones and utilize dynamic consensus algorithm to estimate the per-unit mean value of the microgrid reactive power.Besides,integrator will be used to adaptively adjust the droop characteristic curve and finally realize proportional reactive power sharing among parallel micro sources.The correctness of the proposed control strategies has been verified using MATLAB/Simulink in Chapter three and Chapter four.