Developed a Smart, Connected EV Charger Controller with Features for Load Balancing, Energy Saving, and Safety

The Need

The customer wanted to develop a  low-cost controller for the home and residential EV Charger Stations. This would be a modular design with advanced intelligent features such as:  

• Ability to integrate digital meters, battery interactions, and PV inverter information
• Configure and manage services such as peak service, time of use, and demand response etc.
• Ability to add and attach additional assets 
• Ability to split data streams between the authentication, billing, and the service layer
• The EV charger stations are to be deployed at homes, residential office complexes, shopping malls, and other public charging stations. 
• The controller should enable seamless integration with chargers from multiple ChargePoint vendors.

Our Solution

• Mechanical and Hardware design for chargers 
• Hardware and firmware design and development of the main controller unit with 3  electronic boards –  charge controller, communication controller, and a relay controller. 
• The charge controller board communicates with EV. 
• Communications controller implements the OCPP protocol stack for CMS (Central Management System) interaction. 
• The design used a modular approach, only the communication controller board is required to be configured using CMS.
• A Mobile app is developed in flutter, that connects to the Charger Controller Board, for configuration of parameters, along with charging switch – ON and OFF. 
• The Mobile App displays the charging history and can set maximum charging current. 
• The mobile app supports four languages - English, French, German, and Dutch.
• The RFID Authentication to enable users to start/stop charging using a Charging Card
• Dual channel IEC 62196 for simultaneous communication with 2 EVs, along with a locking mechanism for each of the sockets.
• The communication controller board implements the critical connectivity features and runs the OCPP Client.
• The communication board uses a SoM, which has enough resource for addition of future versions of OCPP Stacks.
• The relay controller, controls the AC current flow to the EVs
• Expansion connectors so that a new MCU can be replaced in future 
• Manufacturing Test suite to support the production process.

Tools & Technologies

• Implemented Custom OCPP1.6J Stack on Linux and tested with OCA Plugfest along with various other OCPP vendors across the globe.
• The Application board ESP32 MCU uses the ESP-IDF FreeRTOS, which is based on Vanilla FreeRTOS v10.4.3. 
• IEC 61851 based basic communication for AC chargers
• ISO 15118 based HLC for DC charging 
• OCPI for roaming features
• Bluetooth connectivity with the mobile application
• Mobile application developed in flutter and supports iOS and Android.
• 10/100Mbps Ethernet connectivity for factory configuration
• Modbus protocol used for device connectivity
• CAN Bus connectivity between communication boards
• Yocto for building the custom Linux image.

System Architecture