Abstract: the age of electric vehicle users is uneven, and it is difficult to read and understand the charging operation process; The incompatibility of payment platforms also brings inconvenience to users. In view of the existing problems, combined with the characteristics of conventional charging piles and taking into account the charging problems of driverless vehicles, a set of new charging equipment integrating automatic charging and manual charging is designed and developed, which can not only be compatible with the existing charging methods, but also realize the docking, charging and fee deduction of automatic charging port for driverless vehicles, so as to improve the intellectualization of charging. The experimental results show that the system runs stably and can solve the problems of inconsistent charging operation and incompatible payment platform.
Key words: charging pile; Driverless vehicle; Automatic docking; Intelligent charging
The production and marketing of new energy electric vehicles and the construction of charging piles / stations are increasing day by day, but there are also problems with the rapid development, such as difficulty in finding charging piles, incompatible payment methods, inconsistent operation steps, etc. Therefore, it is urgent to develop a new type of unattended charging equipment to solve the problems of charging piles in the market.
On the other hand, the development of vehicle driverless technology is becoming more and more mature, and countries and regions including the United States, Japan, Germany and China are further accelerating the layout of driverless field [1-2]. Literature  carried out the research on the evaluation of the intelligent level of driverless vehicles. References [4,5] introduce the main technical means and development status of unmanned driving. It can be seen that it is necessary to study the charging technology for driverless vehicles, whether from the perspective of solving practical problems or from the perspective of technical reserve.
At present, some scholars at home and abroad have conducted relevant research on the charging problem of electric vehicles. Reference  introduces the instrument calibration technology related to electric vehicle charging, and reference  carries out the research on unattended intelligent charging pile. Literature [8,9] discusses the main reasons restricting the development of charging facilities and the research on industrial construction. Reference  designed the embedded control system of intelligent charging pile. However, the current research on charging pile is only for ordinary electric vehicles, which can not meet the charging problem of automatic driving electric vehicles.
Based on technological innovation, this paper proposes a new charging pile, which integrates manual charging and automatic charging. Manual charging is compatible with the existing charging mode of electric vehicles, and automatic charging mode provides a solution to the charging problem of unmanned vehicles.
The charging service system includes operation management platform, cloud, user app, charging pile and electric vehicle, as shown in Figure 1.
For conventional electric vehicles, after driving the vehicle into the charging area, the owner can plug in and plug in the charging gun and swipe the card for authentication to charge; The driverless vehicle first carries out the automatic vehicle identification, and then completes the identification and plug-in of the charging gun and the charging port through the automatic docking technology, so as to carry out the charging operation.
Figure 2 hardware structure diagram of unmanned charging pile
1. System architecture
The acrelcloud charging pile charging operation cloud platform system of ankerui continuously collects and monitors the data of the charging pile station and each charging pile connected to the system through the Internet of things technology, and gives early warning for various faults, such as over-temperature protection of the charger, overvoltage, undervoltage of the charger input and output, insulation detection fault and a series of faults; After the user scans the QR code through the wechat applet and makes payment, the system initiates a charging request and controls the charging pile corresponding to the QR code to complete the charging process of the electric vehicle.
The charging pile can be equipped with WiFi module or GPRS module to access the Internet, cooperate with encryption technology and secret key distribution technology, and directly connect with the cloud based on TCP / IP data interaction protocol. The cloud platform includes all functions of charging and charging pile operation. The specific functions are as follows:
Resource Management: charging station file management, charging pile file management, user file management, charging pile operation monitoring, charging pile abnormal transaction monitoring.
Transaction settlement: charging price strategy management, pre charge management, bill management, revenue and financial statements
User management: user registration, user login, user account management, message management
Charging services: charging facility search, charging facility viewing, map addressing, online self-service payment, charging, charging settlement, navigation, etc
Wechat applet: code scanning, charging, bill payment and other functions
Data service: data collection, SMS reminder, data storage and analysis
Transformer monitoring: monitor the transformer load of the charging station. Each charging station is equipped with an arcm300t wireless meter. In case of overload, the system will automatically dispatch and manage the charging pile, that is, when the load exceeds 50%, the system will limit the power of the newly added charging pile to 50%. When the transformer load exceeds 80%, The system will not allow the new charging point to start charging until the load drops.
2. Platform function
2.1 platform login
Open the cloud platform link in the browser, enter the account name and permission password, and log in to prevent unauthorized personnel from browsing relevant information.
2.2 platform Homepage
The platform homepage provides an overview of the daily number of accounts opened, recharge amount, charge amount, charge degree, charge times and charge duration, the cumulative number of accounts opened, recharge amount, charge amount, charge degree, charge times and charge duration, as well as the corresponding month on month growth and year-on-year growth, as well as the navigation of pile and station distribution map and charging statistics this month.
2.3 real time monitoring
The charging station monitoring page monitors the user's total number of charging guns, the number of charging guns, the number of idle guns, the number of inserted guns, the number of faulty guns, etc., summarizes the user's total charging times, total power and total duration of each pile on that day, and carries out load limit and fault query.
The basic information of the charging gun on the charging pile monitoring page, today's charging power, today's charging times, today's charging duration and cumulative charging power, cumulative charging times, cumulative charging duration, charging voltage and current, etc.
2.4 wechat applet
l Search and use
Wechat applet can be found by scanning QR code and wechat text search. After clicking, it can be added to the applet list
When the user opens the applet for the first time through search or code scanning, he will enter this page. The user can enter the main function page of the applet only after he is authorized to log in
When entering the main function page for the first time, you need to authorize positioning to use map related functions. View the charging station in the current area on the map, view the charging station information, scan the code, charge, map navigation, etc.
Scan the QR code on the charging gun. If the current charging pile is available, you can enter the charging selection page to view the current charging station name, charging gun name, current account balance, electricity price and estimated chargeable capacity, as well as the historical charging records of the current account. Charging methods include charging by time, charging by amount and charging by quantity. Evaluation can be carried out after charging.
The personal information can display the nickname and balance of the current login account, and include functions such as, recharge, recharge record query, Bill query, charging record query, setting payment password, etc
By analyzing the shortcomings of charging piles in the service process, and combined with the development background of driverless technology, this paper designs a new charging pile integrating manual charging mode and automatic charging mode. The new charging equipment is not only compatible with the existing electric vehicles, but also can directly provide charging services for driverless vehicles. To a certain extent, it reduces the cost of updating the charging pile and provides a new idea for the development of charging infrastructure.