Research On Flexible Load Control In Microgrid

Distributed generation composes microgrid to connecting the power grid is making full use of energy form.However,with the increasing penetration of intermittent and uncertain energy sources,the stable operation of power grid is challenged.Especially,when the microgrid is separated to the power grid and operating in islanded.At this time,the problem of supply-demand balance is more serious.In recent years,the proportion of load that can interact with the power grid has been increasing.This kind of “flexible load” which can transform energy has the characteristics of huge regulation potential and flexible distributed regulation.So,it has become an effective means to solve the problem supply-demand in microgrid.Based on the above background,this paper has the following research:This paper takes power electronic load as the research object.The regulation mechanism of active power supply-demand balance and the operation characteristics of power electronic load in microgrid are analyzed.It is analyzed that the unbalanced supply-demand of active power caused by the power changes of distributed generators and loads in islanded microgrid.This paper analyses how to control the operating power of power electronics load to participate to regulates supply-demand balance of active power in islanded microgrid.It is proposed the control strategy that active control of flexible power electronic load considering importance degree in microgrid.To provide support for the balance of supply-demand in islanded microgrid.Besides,the stability of the system is improved.The problem is detail description,which frequency deviation caused by unbalanced supply-demand of active power when the islanded microgrid under droop control.It is analyzed that the operating characteristics and the endurance of power electronic load to frequency change.Taking air-conditioning load as an example,it is discussed the feasibility that active power supply-demand balance regulated by power electronic load in island microgrid.On the basis of the above research,in the view of load,the strategy that active control of flexible power electronic load considering importance degree in microgrid has proposed.In this method,the frequency that power electronic load grid side is measured locally.Then,the balance that active power supply-demand in microgrid can be judged through comparing with preset threshold.The load regulation coefficient is set considering the load of importance degree and the adjustable capacity.So,the power electronic load could be controlled by smooth.The control strategy without communication to control the power electronic load.It makes the power electronic load participation supply-demand regulation smooth and orderly in islanded microgrid.Besides,it reduces the impact for important loads,saves the investment of energy storage system and communication,and ensures the microgrid operation in stable.From the user's view,the strategy that adaptive control of power electronics load considering user intention in islanded microgrid has proposed.However,the load control coefficient is set according the user's intention and the load adjustable capacity.So,it can flexibly control the power electronic load to smoothly adjust its power consumption.As the control strategy regulates the supply-demand of microgrid smoothly and orderly according to the user's wishes and adjustable capacity.The user satisfaction is improved and the microgrid operates more steadily.Finally,the simulation is built in Matlab.The simulation waveforms under different working conditions are compared.The results show that the two control strategies are effective for regulating the supply-demand balance in islanded microgrid.