With the development of electric vehicles in China, the fault monitoring and warning systems for the charging process of electric vehicles have received the industry’s attention. A method for the monitoring and warning of electric vehicle charging faults based on a battery model is proposed in this paper. Through online estimation of the state of charge of the power battery model and battery electromotive force, parameters such as battery state of charge, voltage, and temperature can be adjusted in real time to simulate the charging response of the power battery, which can simulate power batteries of different types, specifications, and parameters. During the charging process, CAN (Controller Area Network) bus monitoring technology is used to receive and analyze the charging information of the charger, as well as the battery charging information and battery charging demand information. The charging response information simulated by the battery model is compared with the battery charging state information, and the charging state information of the charger is compared with the battery charging demand information to determine whether the charging process is normal. When it is judged that a charging fault occurs, a fault warning signal is sent. This method can identify more than 10 types of faults, including the failure of the BMS (Battery Management System) function. The comparison and analysis of actual charging accident data and power battery model data verifies the feasibility of the charging fault monitoring method proposed in this paper.

Performance status evaluation is essential for the safe running of electric vehicle (EV) charging infrastructure. With the development of the EV industry, the EV charging infrastructure industry has advanced considerably. Safe and reliable operation of the charging infrastructure is important for the development of EVs. As such, we propose a comprehensive evaluation method to assess the performance condition of an EV charging infrastructure. First, based on the analysis of the existing EV charging principles, we established an evaluation index system for EV charging infrastructure. Second, the subjective weight, objective weight, and comprehensive weight of the index system were determined through analytic hierarchy processes (AHP) and the entropy weight method. Then, we used fuzzy comprehensive evaluation to appraise the performance of the charging infrastructure through expert investigation. Finally, based on the actual data from an EV charger, the performance conditions of the EV charging infrastructure were evaluated to demonstrate the feasibility of the method and the reliability of the index system.

With the development of electric vehicles in China, the impact of the electrical performance of electric vehicle charging equipment on electric vehicle battery can not be ignored. A test system for the field test of off-board charger electrical performance is presented in this paper. The test system is composed of hardware devices and control system. The hardware devices include a power module, a load module, a measurement module, and a protection module. The load module uses a lightweight controllable charging load to reduce the weight and volume of test system for field test needs. The control system can control the test process and analysis test data. Taking the stabilized voltage precision test as an example, an off-board charger is tested and the test results are analyzed in this paper.

In view of the fact that the electronic load used in the on-site detection of the electric vehicle off-board charger is large and heavy, and it would be limited by some external factors such as the space and load of the detection vehicle and the height of the underground garage. In addition, considering that if using the power batteries of mobile detection vehicle as charging load directly, it's charging modes and parameters are unitary, the state of charge (SOC) and electromotive force also cannot be flexibly set, which would result in long charging time, low efficiency, limited test range and items. This paper proposes a topological scheme that the lightweight controllable charging load consists of a vehicle-mounted power battery pack and a cascaded DC/DC converter, researches the double-closed loop control methods such as constant input voltage, constant load resistance as well, further comes true the typical working modes: constant input voltage, constant load resistance. Moreover the operating modes have the ability to continuously adjust in the rated range. In a word, the proposed scheme can achieve self-test of the off-board charger while reducing the weight of the charging load. Finally, the simulation model in Matlab/Simulink is established to verify the feasibility of the proposed topology and the effectiveness of the control methods.