Power Quality Adaptive Regulation Method Of Regional Grid Applied To V2G System

With the global energy shortage,environmental degradation,climate disorders and other problems continue to intensify,green,environmental protection,clean and efficient energy utilization model has become the mainstream of today's society,electric vehicles as a representative of new energy technology in the field of transportation is playing an increasingly important role.Due to the continuous development of technology and the strong support of policies,electric vehicles are increasingly appearing in people's vision.The influx of electric vehicles poses a huge challenge to the power grid and provides new solutions to the power system.Large-scale electric vehicles connect to the power grid,which can be regarded as a large number of distributed energy storage units connected to the power grid.The energy control of the energy storage structure feedback grid can realize functions including frequency modulation and voltage regulation,peak clipping and valley filling,and improvement of power quality.In this context,the paper takes the vehicle-to-grid(V2G)system as the basis of research,and considers the principle of adaptive impedance combined with V2G grid-connected control technology.Through the topology and model analysis of this whole system,the specific characteristics of adaptive impedance in the harmo nic domain and fundamental domain are expounded.Using the advantages of adaptive impedance in reactive power and harmonic compensation,the deficiencies in the traditional droop control strategy are improved.At the same time,the correctness of the system function and theory is verified by constructing the system simulation experiment model.In this paper,the V2G grid-connected system with adaptive impedance control method is taken as the core,and the following contents are introduced.Firstly,to introduces the topology of power quality adaptive control system applied to V2G system from the side of the structure and wiring principle,such equivalent circuit model and mathematical model under different frequency conditions are established.According to those models,the relationship between adaptive impedance and related variables,which include load harmonic current,background harmonic voltage and network side harmonic curr ent,under harmonic conditions is derived.The mathematical expression of adaptive impedance participating in reactive power dynamic compensation under the condition of fundamental wave is obtained.Then,the analysis of the above relations and expressions gives the special implementation conditions of adaptive impedance in the case of harmonic suppression and reactive power compensation,and clarifies the specific working principle and corresponding perform ance characteristics of adaptive impedance in different working modes.Secondly,based on the research of traditional droop control,the adaptive impedance control method is introduced,and the integrated control strategy of grid-connected power quality for V2G system is proposed.Referring to the traditional droop control method,through the parameter design of its power decoupling control,the pure inductive design of the output branch of the inverter is realized,which creates conditions for the active tracking compensation of subsequent reactive power and harmonics.At the same time,the adaptive impedance control method is used to improve the reactive power compensation link in the traditional droop control method,eliminate the poor dynamic response ability of the traditional droop control in the state of grid-connected and the static error problem of reactive power compensation caused by the presence of virtual impedance,so as to satisfy the precise output of the reactive power compensation of the system by the inverter.In addition,giving full play to the advantages of the V2G system interface inverter,adding harmonic variables on the basis of the original fundamental wave control,and expanding the overall scope of the control structure.Realizing dynamic compensation of harmonic and reactive power while grid-connected active power is scheduled.Finally,in order to better understand the feasibility of t he proposed power quality adaptive control system and related control methods applied to V2G systems,a small simulation test system is built based on the existing conditions.The system's overall wiring structure,main parameter design and system simulati on debugging were introduced.The test system's working characteristics under fundamental and harmonic conditions were obtained.Achieving a high degree of unity proposed theoretical principles and control system simulation model.