using the ISO/IEC 15118 standard to exchange information on battery capacity, maximum power allowed, ... Agents of the system. Electric vehicle supply ...
Electric vehicles charging reservation based on OCPP Simone Orcioni, Luca Buccolini, Adriana Ricci, Massimo Conti Dip. di Ingegneria dell’Informazione, Università Politecnica delle Marche
18th IEEE International Conference on Environment and Electrical Engineering
Motivations •
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Full Electric Vehicle: § Limited Autonomy (150 Km), § high cost of battery, § limited driving range, § high recharge time, § lack of adequate recharge infrastructure. Impact on Power Grid: § Fast recharge (30 min) requires high power (45 kW). § An high number of electric vehicles has a great impact on power grid.
Objectives •
OCPP protocol extension to the reservation phase. It allows the user negotiate the following recharge parameters: initial time, duration, price, percentage of final charge, power required.
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Introduction of the flexibility from user side and charging station side during the reservation phase. This allows the optimization of the energy management and income from the charging station side, and the cost and customer satisfaction from the user side.
The OCPP standard • •
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OCPP is an open standard introduced by the OCA (Open Charge Alliance) a consortium of public and private organizations. The purpose of OCA is to promote the creation of an free and open protocol independent from the characteristics of each manufacturer and that can allow the management of every single factor within the recharging operation. The use of OCPP allows to: § Monitor and control access to individual charging stations; Check and manage the recharge status; Send data to individual users and managers; Fulfill the payment procedure; Implement the reservation mechanisms and management of the electricity grid. Our extensions of the OCPP: § § § §
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§ Introduction of the reservation phase for the user. § Introduction of user flexibility.
Agents of the system Reservation app
User Database
EVSE Central System
EV
Agents of the system Electric Vehicle (EV) •
The EV communicate with the charging station through powerline using the ISO/IEC 15118 standard to exchange information on battery capacity, maximum power allowed, ...
Electric vehicle supply equipment (EVSE) • It enables interoperability with all types of electrical vehicles, provides to the user information on the cost, maximum available power directly when he is preforming a recharge. It exchanges information with the database through the central system to allow reservation.
User •
The user defines the parameters of the recharge and performs the reservation with the central system through the smartphone or with a wide range wireless protocol (e.g. 4G/5G connection) already existing in the EV (like the Tesla models). Furthermore, he can define the parameters of the recharge directly with the EVSE, if no reservation has been performed, and monitor the actual recharge.
Agents of the system DataBase •
The database stores the data of all the EVSE available in the region, of the user enabled to use the charging stations, of all the reservations and billing information.
Central System •
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The central system coordinates all the operations handling the requests from both the EVSE and the user and creates the interface with the database for all the required functions. Some of the features of the central system are already present in the OCPP standard, while others have been added to manage the reservation phase: § Creating a new user account; § Login users already registered; § Creating a reservation for a certain time; § Canceling bookings made by the user; § Search for the best solutions for charging.
DataBase structure Charging_Stations Charging_Station_Id Manufacturer_Id Contry_id Region_id Province_id City_id District_id IP_Address Accessibility Address Latitude Longitude Info N_of_Connectors
Connectors Charging_Station_Id Connector_Id Connecor_Error_Code Connector_Status Reserveable Availability Max_Amp Phase Voltage Charging_Protocol Current Connector_Type Charging_Capability
Reservations Charging_Station_Id Province_id User Connector_Id Priority Reservation_time End_time Slots Power Price Time
User Android_Id Username Password Email
Exchange of information during reservation Charging Station
Central System
Database
User App
Login request get user user data and passaword get charging station data charging station data get free slots
Reservation request
free slots send best solutions
confirm insert reservation response ReserveNow.req
reservation done
Reservation Message from user to central system. The user specifies his requirements and flexibility § § § §
username: username Charging Station androidId: smartphone Id chargingStationId: identification of the charging station capacity: capacity of the car battery (kWh)
§ § § § §
power: recharge power (kW) initialCharge: percentage of initial charge of the car finalCharge: percentage of final charge desired reservationTime: start date and time of recharge from and to: extremes of the time interval of availability
§ § § §
priorityTime: flexibility on the instant of top-up priorityDuration: flexibility over the duration of the recharge priorityCharge: flexibility on the final charge reached priorityPrice: flexibility on the cost of recharge.
Central System
Database
User App
Login request get user user data and passaword get charging station data charging station data get free slots
Reservation request
free slots send best solutions
ReserveNow.req
confirm insert reservation response reservation done
Reservation App
User flexibility Stars 0 1 2 3 4 5
Flexibility maximum high medium-high medium-low low minimum
Customer Satisfaction
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On the basis of user flexibility the central system selects the first “best” solutions
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Customer satisfaction means the satisfaction of a customer deriving from the use of a good or a service.
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The first solutions (five in our test example) will be sent to the user and he will select one of them in case he confirms the reservation.
Customer satisfaction function Used to order the different possible solutions to the user on the basis of the explicitly expressed flexibilities 4des − 4f $% − $' 01 − 0min : − :min !=# , -. + # , -3 + # , -9 + # , -; $norm 0norm 4norm :norm
• • • • • • • • • •
2 # E, - = 1 + 10I∗K $%: desired time of start of recharge; $': effective time of start of recharge; 01: recharge duration; 0: minimum recharge duration; 4?@A: desired percentage of final charge; 4B: effective percentage of final charge; :: recharge cost; :: minimum fixed cost of the recharge; $>CDCD< , 4>CDCD
