Research On Key Technologies Of Electric Vehicle Participating In Power Grid Frequency Regulation

Under the "double carbon" goal,large-scale renewable energy access and the withdrawal of traditional units will cause frequency problems,and traditional units will face the challenge of frequency regulation.Electric vehicle(EV)has fast response speed and flexible regulation.It’s one of the feasible methods to guide EV to participate in power grid frequency regulation through charge and discharge to deal with frequency regulation problem in new power system.The paper main work includes:Firstly,the adaptive range and characteristics of the main frequency regulation modes of power system are analyzed,as well as the process,principle and advantages of EV participating in frequency regulation.Compare the EV battery type and the equivalent circuit model of common lithium battery,build the power adjustment model of EV participating in frequency regulation and analyze the charge and discharge characteristics of lithium battery,model the parameters in Thevenin model according to the change of voltage under the excitation of mixed power pulse characteristic experimental current,build the Thevenin model in Matlab / Simulink,and analyze the response characteristics of battery by inputting different pulse current signals,It lays a foundation for EV to participate in the research of power grid frequency regulation control strategy.Then,the frequency regulation model of the main components of the power system is analyzed,and the control strategy of EV participating in the primary and secondary frequency regulation is proposed.According to the types of users’ risk preference,EV users are divided into four types: neutral type,risky type,conservative type and mixed type.The willingness model of EV users to participate in frequency regulation when facing the high and low state of charge(SOC)is established.The EV participating in the primary frequency regulation control strategy considering the type of user risk preference and the EV participating in the secondary frequency regulation control strategy based on Fuzzy-PID control are proposed.The frequency regulation simulation model with EV is established in Matlab / Simulink.Combined with different scenarios,the effect and effectiveness of the proposed EV participating in the primary and secondary frequency regulation control strategy are verified by analyzing the changes of system frequency,unit output and EV battery SOC under load disturbance.Finally,a secondary frequency regulation model considering the dynamic variation of EV quantity is proposed.Analyze the travel characteristics,state characteristics and SOC characteristics of electric buses,electric taxis,electric business vehicles,normal electric private cars,early departure and late return electric private cars and night shift electric private cars,and establish a secondary frequency regulation model considering the dynamic variation of EV quantity.The number of controllable EVs at each time is calculated by Monte Carlo method.Considering the EV capacity and power constraints,the centralized equivalent model of each type of EV participating in frequency regulation is established.Through MATLAB / Simulink modeling and simulation,the changes of controllable EV quantity,capacity,unit output and SOC under continuous load disturbance are analyzed to verify the frequency regulation effect of the secondary frequency regulation model considering the dynamic variation of EV quantity.