Research On DC Charging Station Detection Based On Finite State Machine

With the rapid development of the new energy electric vehicle industry,charging stations,as basic supporting facilities for electric vehicles,have been deployed in large numbers nationwide.For DC charging station,delivery inspection and regular maintenance can effectively guarantee the safety and reliability of its power supply output.However,the existing research has little consideration on the correlation between the running states,and the intelligent algorithms used for fault detection also have the problems of high complexity and difficult to be applied in embedded systems.In this paper,finite state machine is used to establish the simulation model of DC charging station running state transition,and fault dictionary method is used to realize the DC charging station detection system,which has certain theoretical value and practical significance.The model completes the state division of DC charging station,takes charging state and trigger condition as input variables,and test behavior as output variable,and constructs a finite state machine model of the detection process.The simulation results show that the model can accurately identify the running state of charging station.The system selects STM32F429IGT6 as the main controller;uses DHT11 to monitor the ambient temperature and humidity in real time;reads the preset test case in SD card through SDIO interface and writes the communication test data to it;uses CAN analyzer to listen to the message of charging station and forward the preset test case;reads the real-time clock to time the interval between receiving and sending the message;uses 18650 lithium battery,relay,sliding rheostat and INA282 module to set up battery test circuit to realize the collection of electric parameters;displays the parameter configuration,communication process and test result through LCD screen.The main research results of this paper are as follows:(1)Through in-depth study of national standards,the test items of protocol consistency and interoperability of DC charging station are determined,the design scheme of DC charging station detection system is given,and the hardware structure and software function design of the system are completed.(2)Using MATLAB/Stateflow tool,a simulation model of DC charging station state migration based on finite state machine is established to analyze and identify the running state of charging station.Experiments show that the output results of the control strategy of the model are consistent with the state transition order of charging station,which verifies the correctness and effectiveness of the model.(3)A DC charging station detection scheme based on fault dictionary method is proposed.The communication messages of charging stations and the fault conditions of peripheral components are processed into fault eigenvalues by function mapping,and the fault diagnosis dictionary of charging stations is established.Then,the fault detection of charging station is realized by comparing the dictionary fault parameters and charging station detection data.The test results show that the fault dictionary method has good diagnostic ability for detecting communication faults of DC charging stations.