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Research On Adaptive Droop Control Strategy Of Microgrid

Posted on:2019-01-05Degree:MasterType:Thesis
Country:ChinaCandidate:M L ZhengFull Text:PDF
GTID:2392330599977574Subject:Control engineering
Abstract/Summary:PDF Full Text Request
The microgrid consists of a plurality of distributed generations which are connected in parallel.As an effective means for improving the reliability of the power system,the microgrid can provide power in areas where there is no centralized power infrastructure.When microgrid is operating in island mode,coordinated control strategies can ensure that the distributed generations provide specified power,which is very important for stable operation of the system.Adaptive droop control strategy is an improved droop.In addition,a voltage compensation controller is introduced in the adaptive droop control based on transient components to compensate the asymmetric voltages in the microgrid caused by unbalanced loads.These control strategies got a good result.In the microgrid system based on adaptive droop control,the distributed control strategy of microgrid based on the consistency algorithm is established.The adaptive control based on consistency algorithm is approved to solve the problem that reactive power of distributed generations cannot be shared proportionall y through the traditional hierarchical control of microgrids.The distributed controller replaces the traditional primary and secondary controllers,and combines the voltage prediction to control the global voltage and the provided voltage of distributed generations,at the same time,the nominal power of each distributed generation is balanced.Then,an adaptive droop control strategy based on the consensus algorithm is designed.The adaptive droop control based on consensus algorithm is used to solv e the problem which are often encountered when the microgrid is applied.The control strategy is approved that the power of distributed generations can't be shared in proportion and the problem that purely distributed algorithms is over-dependence on communication systems.The use of droop can offset excessive dependence of the system on communication in the microgrid system based on the consensus algorithm through the characteristics of decentralized control.In addition,the consistency algorithm can adjust the set value of the droop control to eliminate the deviation caused by the traditional droop control and solve the problem that the reactive power can't be shared proportionally.For the unbalanced voltage condition of the microgrid,an adaptive droop control system based on transient components is designed.In the unbalanced microgrid,the positive and negative sequence components of the voltage and current signals are separated by the extraction method of the positive and negative sequence components based on the second-order generalized integral.The adaptive droop control based on the transient components improves the power oscillation.In order to compensate for unbalanced voltage,the actual value of the voltage unbalance degree is compared with the allowable voltage unbalance degree requirement of the power system,and the deviation is sent to the proportional resonance regulator.And then correct the reference value of voltage controller through the resulting voltage compensation signal.A voltage and current loops based on an improved proportional resonance is used to obtain the system voltage reference value,and the voltage and current output of the inverter are improved.
Keywords/Search Tags:microgrid, adaptive droop control, consistency algorithm, voltage unbalance
PDF Full Text Request
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