As global attention to environmental protection and sustainable development increases, electric vehicles (EVs) are rapidly becoming the mainstream choice for future transportation. However, the widespread adoption of EVs brings several challenges, with one of the most significant being how to effectively manage and optimize the charging process. Traditional charging methods struggle to meet modern EV users' demands for charging speed, convenience, security and energy efficiency. To address these challenges, smart charging technology has emerged. Smart charging is not just about a simple charging process; it is an integrated solution that combines advanced communication technologies, data analysis, and energy management
ISO 15118 standard for smart charging applications
ISO 15118 is an international standard for communication between EVs and charging stations, facilitating the exchange of information for authentication, authorization, billing, and flexible load control. It aims to support smart charging functions, including the "Plug and Charge" feature, which enables automatic authentication and payment. With this feature, the EV simply needs to be plugged into the charging station to automatically start charging, eliminating additional user authentication steps and streamlining the payment process, significantly enhancing user convenience.
Additionally, ISO 15118 allows for bidirectional communication between EVs and charging stations, enabling energy transfer both from the vehicle to the charging station and vice versa. The standard supports power adjustment and charging scheduling, integrating with smart grids to allow EVs to limit charging power during peak demand periods or charge during off-peak times. This helps prevent grid overload, balance grid load, and improve the overall efficiency and stability of the power system.
ISO 15118 also ensures robust encryption protection for data transmission during communication, safeguarding user information and transaction data. Beyond traditional wired communication, the standard supports wireless communication technologies, further enhancing flexibility and adaptability.
Furthermore, ISO 15118 includes energy management capabilities, allowing EVs and charging stations to negotiate the optimal charging strategy to optimize energy usage and reduce charging costs. These features make ISO 15118 a crucial standard in the smart charging of EVs, promoting deep integration between EVs and the grid, improving charging efficiency, and enhancing user experience.
Key building blocks of electric vehicle charging stations
EV charging stations provide power for charging EVs. A typical EV charging station consists of at least one smart control board (Supply Equipment Communication Controller, SECC) and one power socket board. The smart controller is responsible for managing high-level communication and functionality, services, and connection to remote servers, while the power socket board is responsible for safety, low level communication, distributing and measuring energy. In order to meet the diverse needs of EV charging, charging equipment not only needs to provide flexible options for AC or DC power supply but also needs to provide a variety of functions.
Due to legislative requirements in various countries to improve the accuracy of fair payments, fuel taxes recovery, and provide power grid load balancing and quality analysis, charging equipment needs to provide precise power transmission measurement. Additionally, charging equipment needs to support major EV security standards contained within OCPP2.x, ISO 15118, and PKI, as well as support GDPR, calibration law "Eichrecht" and confidentiality, along with safety standards such as IEC61508 and SIL2, to enhance the security and safety of edge devices.
Furthermore, cloud service login for charging equipment needs to simplify the provisioning and ownership processes while using zero-touch onboarding to simplify and maintain a high level of security and confidence in the connection to authenticated devices. On the other hand, preparations need to be made for large-scale deployment, integrating cost-optimized artificial intelligence (AI) and machine learning (ML) technologies for consumption profiling and anomaly detection analysis. Moreover, the product lifespan of charging equipment needs to exceed 10 or 15 years, with a service life of 10 to 20 years, and be robust and durable, suitable for harsh environments, to maintain the availability and reliability of the entire system.
To build a complete EV charging system, the following key building blocks are needed. First, metrology capability is required to accurately measure energy flow between the charger and the vehicle, calculate energy billing consumption, manage the safe switching and low-level communication of EVs, and support high-precision temperature sensors for temperature monitoring, enabling safety and anomaly detection. Additionally, an NFC bridge can be used to serve as an isolated communication channel for the metrology MCU and can also be used in manufacturing, commissioning, and updating processes.
Furthermore, a controller board (SECC) is needed to manage the main functions and services of the power supply equipment, including any high-level communication and protocol stacks such as ISO 15118, OCPP, and connection to the backend, with options including bare-metal services and RTOS. For solutions running the Linux® operating system, screens can be used for Media advertising to add greater value.
Security is an indispensable feature of charging equipment, requiring end-to-end verification using cryptographic keys to protect energy usage and billing data, securely and seamlessly onboard EV chargers to backend servers and cloud services for remote management, and allowing software and firmware to be configured, updated, and verified. In terms of external communication capabilities, flexible mix of communication functions can be combined based on location, region, and type of charging equipment, supporting communication solutions for specific regions, including Wi-Fi®, PLC, NB-IoT, Sigfox, etc.
Providing a high-level electric vehicle charging solution
EV charging stations require high levels of efficiency, accuracy, connectivity, and security. NXP's solutions meet the requirements for precise power measurement, equipment management, and data security. NXP's extensive technical support enables faster time to market while reducing complexity and costs, and NXP's product lifespan program supports longer product lifecycles.
To meet the fast-charging needs of EVs, NXP has introduced the EasyEVSE solution, which fully leverages the potential of the ISO 15118 standard. It offers the convenience of plug-and-charge, bidirectional power transfer using EV batteries as energy sources, and the ability to use vehicle energy for load balancing or act as a generator during power blackout or high energy costs.
NXP's EasyEVSE solution combines efficiency and sustainability with reliability and security. It provides rugged durability suitable for harsh environments and is cost-optimized, striking a balance between enhanced performance and commercial demands. It also offers faster product upgrade capabilities, common hardware and software platform reuse, secure connectivity, support for zero-touch setup, industry security certifications, and OTA update solutions.
NXP's EasyEVSE EV charging station development platform simplifies the process of building EV charging systems by integrating multiple technology building blocks. It supports cloud connectivity to meet various needs for building connected EV charging stations, providing hardware configuration guides and sample software. Its modular, scalable platform supports device-to-cloud and cloud-to-device communication, accurate energy billing, and one-tap NFC authentication.
The EasyEVSE EV charging station development platform connects to the cloud via Ethernet or Wi-Fi and provides verified cloud services such as Microsoft Azure IoT Central. It enhances security with the EdgeLock™ SE050 security element and supports accurate energy billing with pre-certified Kinetis M metrology MCU. It also features high-performance NFC front-end for one-tap authentication and utilizes NXP and partner development tools to implement additional differentiated features on the same platform.
A comprehensive product line to meet the needs of electric vehicle charging stations
NXP's EasyEVSE MPU EV charging station development platform integrates a complete range of products from NXP. This includes NXP's i.MX 9x series application processors, which feature higher-performance application cores, an independent MCU-like real-time domain, Energy Flex architecture, the state-of-the-art security of EdgeLock® security enclave, and dedicated multi-sensory data processing engines (graphics, imaging, display, audio, and voice).
Additionally, NXP's EasyEVSE MCU EV utilizes the i.MX RTx series microcontrollers, which incorporate various high-performance Arm® Cortex®-M and DSP cores. By integrating PXP, 2D GPU, and PowerQuad DSP coprocessor, they combine usability with high-performance processing, providing unprecedented reliability, high-level of integration, and security.
NXP's KM series is based on Arm® Cortex®-M0+ core metrology microcontrollers. The low-power Arm Cortex-M0+ MCU series is designed to support single-chip solutions for one-, two-, and three-phase electricity meters, flow meters, and other precision measurement applications.
The MCX N series is based on the Arm® Cortex®-M33 MCU series, utilizing cost-effective 40-nm NVM processing technology. It offers significant performance enhancements, hardware DSP, all on-chip RAM with parity or ECC, renewed Crypto security features, precise analog additional functions, and Arm® TrustZone®-M for separation and access control isolation for certified software and resources.
NXP's IW61x series supports Wi-Fi® 6/Bluetooth® 5.4/802.15.1 tri-band radio, including a full-featured Wi-Fi subsystem supported by NXP's 802.11ax (Wi-Fi 6) technology. Compared to the previous generation Wi-Fi standard, it delivers higher throughput, better network efficiency, lower latency, and greater coverage range.
The PN7160 series is an NFC plug-and-play controller with integrated firmware. Embedded NFC firmware reduces the need for host interaction and minimizes code size, making design-in easier. It supports all NFC Forum modes, provides drivers for Android and Linux, and supports RTOS and no OS applications.
NXP's SE051 series is an IoT security solution supporting upgradability and custom applets. It enables in the field applet updates and provides proven CC EAL 6+ certified security, with support AVA_VAN.5 up to the OS-level.
Conclusion
The popularization of EVs is undoubtedly an inevitable trend in future transportation development, but to truly achieve this goal, the application and development of smart charging technology are crucial. The introduction of international standards such as ISO 15118 has made communication between EVs and charging infrastructure more interoperable, efficient and secure. The NXP smart charging platform and solutions introduced in this article will help accelerate the development of EV charging applications and are worthy of further exploration and adoption.