This article was published on EE Power, July 28, 2024
While charging stations featuring AC and DC charging technology, combined systems, and megawatt charging differ slightly from model to model, most off-the-shelf options do not adequately meet requirements the way custom solutions can.
Electric vehicle charging station providers gain a significant market advantage by integrating new, innovative functionalities that differentiate them from the competition. Completely new developments, however, are time-consuming and costly. Charging station controllers must meet industry standards, from energy and load management to vehicle communication to user identification and billing mechanisms. Networking, remote maintenance, update capability, and security are all vital to the system’s success. While charging stations with AC and DC charging technology, combined systems, and megawatt charging differ only slightly from model to model, most off-the-shelf options miss the mark on some of these requirements.
A Custom EV Charging Station
Phytec is addressing this issue by developing specialized electronics for EV charging stations in collaboration with Pionix, an open-source software provider for EV chargers.
The project began in discussions with Qwello, a full-service public charging operator with a vision to create easy-access solutions and services contributing to a new urban e-mobility lifestyle. For its new CP22 charging station, Qwello needed simultaneous dual charging and enablement of AC charging with up to 22 kW power while meeting certification standards according to Eichrecht (German calibration law). This legislation mandates that all public electric vehicle charging stations be equipped with certified and calibrated electric meters for accuracy and reliability.
The end application was designed to use a single display and payment terminal for two parallel charging processes with Cloud integration and parking sensors that detect unauthorized vehicles. LEDs on the charger show availability status visible from the road, allowing drivers to see whether the station is free, reserved, currently charging, blocked by an unauthorized parker, or out of order. All components are housed in a minimalist, slim column, suitable for the urban landscape and optimized for tightly confined public parking spaces.
Phytec created a specification based on its phyCORE-AM62x System On Module (SOM), populated with Texas Instruments’ AM62xx processor variants to meet these requirements. The SOM offers support for two displays, numerous interfaces for integrating sensors and peripherals, and a dedicated microcontroller that can control the safety-critical charging process. The SOM connects to a carrier board with AC charging outputs, Gigabit Ethernet, dual-band Wi-Fi, BLE, an LTE module, Modbus, and CAN FD. A trusted platform module (TPM 2.0) is populated on the carrier board to comply with security requirements, including the Cyber Resilience Act.
Software Support for Charging Protocols
Phytec provided an adapted board support package, based on Yocto Linux, for the AM62xx processor on the SOM that integrates with a charging-specific EVerest software stack from Pionix. This stack supports all common charging protocols such as Plug & Charge per ISO15118 standards, Autocharge, and EIM/RFID readers; features integrated energy management with load balancing and allows authentication and payment through common standards such as OCPP 1.6J and OCPP 2.0.1. The safety-critical firmware and charging-station-specific technologies, such as backup power supply, protection against DC ground faults, and support for automatic plug locking, are all part of the EVerest package.
The Qwello charging controller specification was completed in June 2023. In November, after only six months of development, Phytec delivered the prototypes, successfully receiving TÜV approval. After minor engineering changes, volume production is planned for the third quarter of 2024
A Universal Modular System for AC/DC Charging Solutions
In parallel to developing custom electronics for Qwello, and along with Qwello’s collaborative input, Phytec and Pionix created the phyVERSO-EVSE universal charging controller solution that offers additional support for both AC and DC charging systems, including mixed configurations. The versatility of phyVERSO-EVSE makes it suitable for developing calibration-compliant wall boxes for private and public use, charging stations, and megawatt charging parks. The phyVERSO-EVSE is delivered with a Linux operating system and Pionix charging firmware on the SOM. It has been tested for compatibility with the EVerest charging operating system. A customized version of this open-source software is available for download.
Pionix offers this custom software bundled with its comprehensive BaseCamp charging software. This framework supports numerous protocols for integrating infrastructure, vehicles, and payment systems. A local MQTT server enables communication and network integration. End users and EVSE device developers can build their application software directly on this stack.
A Modular Design Approach
In the future, this modular design approach will enable the custom adaptation of the phyVERSO for other end-use projects. Integration of additional I/Os, changes to connectors, or adjustments to the PCB size, including production and delivery of prototypes, can be achieved within a few weeks. The collaboration between Phytec and Pionix offers a hardware and software package on which customers can directly build their own applications, enabling abundant possibilities for developing customized charging stations.
