As Electric Vehicles (EVs) become increasingly popular, their supporting infrastructure is also developing rapidly. Electric Vehicle Supply Equipment (EVSE) is a critical component of this infrastructure. Commonly referred to as charging stations, EVSE encompasses much more than just a power outlet. This article explores the concept and importance of EVSE, how its integration with Wi-SUN (Wireless Smart Ubiquitous Network) Field Area Networks (FAN) can enhance EV charging infrastructure, and the related solutions offered by Silicon Labs.
Key design considerations for electric vehicle supply equipment
EVSE refers to the components that deliver electrical energy from an external source to an EV's battery while ensuring safety, efficiency, and reliability. It includes electrical conductors, connectors, plugs, sockets, as well as the software and communication protocols necessary for managing the charging process.
EVSE is crucial for the widespread adoption of electric vehicles. It ensures EVs can be charged safely and efficiently whether at home, at work, or on the go. As the number of EVs grows, a robust and reliable charging infrastructure becomes essential. EVSE plays a key role in meeting this demand and supporting the transition to sustainable transportation. A new feature called Vehicle-to-Grid (V2G) has been introduced and is becoming mandatory in some regions. In the future, EVs are envisioned to serve as backup batteries for homes or even as energy reserves for the power grid.
When designing EVSE, several key factors must be considered. First is load management. Commercial installations require balancing charging currents to maintain stable power distribution and prevent grid overload. In residential installations, load management is particularly important to prevent fuses/circuit breakers from tripping. Second, demand response must be considered. When the grid is under stress, Distribution System Operators (DSOs) and Transmission System Operators (TSOs) can use EV chargers as flexible loads, alleviating strain on the grid by adjusting charging rates or temporarily stopping charging.
On the other hand, identification is also very important. User and vehicle identification prevents unauthorized charging, and user identification information must match the latest authorization database. Accurate billing is another critical requirement. Proper identification ensures that the electricity consumed is billed to the correct EVSE unit. This is essential for both EV owners and charging station operators to avoid billing discrepancies.
Comprehensive EVSE solutions for residential and commercial charging
EVSE is vital for the growing adoption of electric vehicles. As the market expands, it is crucial to understand the various solutions available for residential and commercial charging, ranging from AC to DC, covering residential charging and commercial application scenarios, and incorporating the concept of Vehicle-to-Grid (V2G) technology.
Residential charging solutions primarily focus on convenience and accessibility for individual users. These solutions typically use AC charging, suitable for overnight charging at home. Currently, several wireless technologies are applicable for residential EVSE. Wi-Fi can provide reliable connectivity for home charging stations, allowing users to remotely monitor and control their EVSE. Furthermore, integrating the Matter protocol over Wi-Fi into residential EV charging systems can enhance connectivity and interoperability, supporting features like load control, time-of-use optimization, and cost optimization via Energy Management clusters.
On the other hand, Bluetooth Low Energy (BLE) can be used to provide a cost-effective solution for short-range communication between the EVSE and the user's smartphone or other devices. Sub-GHz RF Mesh/Wi-SUN ensures robust communication over long distances, making it very suitable for outdoor installations and places like urban basements.
Commercial EVSE solutions are designed to support large-scale installations such as community garages, parking lots, and other public spaces. These solutions often employ AC charging to meet high-volume usage demands. Wi-SUN FAN technology addresses a subset of these facilities, providing reliable connectivity and management for large commercial environments. Additionally, there are options for large-scale DC deployments which, although smaller in scale, offer robust solutions for specific application scenarios. These DC deployments can also utilize wired or cellular connections to ensure optimal performance.
Integrating smart EV charging stations using Wi-SUN technology into a unified smart city network offers numerous advantages. This unified network can encompass smart street lighting, traffic signals, smart parking systems, and more, creating a coordinated and efficient urban environment.
Addressing EV charging challenges with Wi-SUN FAN
To address the key design considerations for EVSE mentioned above, several challenges need to be resolved. The first is the communication challenge in parking garages. Traditional 2.4GHz wireless solutions often fail in parking garages due to obstructions, long distances, and scalability issues. Wi-SUN FAN operates in the Sub-GHz frequency band, providing stable connectivity even in complex environments like parking garages. Its multi-hop network capability ensures reliable communication over long distances and around obstacles, guaranteeing the continuous and efficient operation of EVSE systems.
Furthermore, installation and maintenance costs must be considered, as installing and maintaining wired communication systems is expensive and labor-intensive. Wi-SUN FAN offers a wireless alternative that is easier and cheaper to install and maintain, significantly reducing the need for extensive wiring. This substantially lowers the overall costs for EVSE vendors and integrators. On the other hand, ensuring stable and reliable connectivity in various environments is crucial for EVSE operation. Wi-SUN FAN provides a robust mesh network that ensures reliable communication across various smart city applications.
Leveraging existing network infrastructure is a smart business move that can transform more streetlights into convenient on-street charging points. This unified connectivity enables seamless integration of EV charging stations with other smart infrastructure like streetlights, traffic signals, and parking systems. Cities can optimize energy usage and reduce operational costs. For example, streetlights can dim during low-traffic periods, and EV chargers can operate during off-peak hours, thereby balancing the load on the electrical grid.
A unified network supports real-time monitoring and control of various services. Drivers can receive notifications about available parking spots, optimal charging times, and traffic conditions, enhancing convenience and alleviating congestion, thus improving the user experience. However, utilities and smart cities must tackle the challenge of integrating multiple applications and vendors across a network that includes advanced metering infrastructure, intelligent transportation systems, smart lighting, and more. EV charging will simply become another application that needs to be managed.
When deploying EV charging stations in smart cities, connectivity and interoperability are paramount. Wi-SUN FAN is the only open standards-based communication network that ensures the necessary security, reliability, and interoperability. This is crucial for building a cohesive smart city ecosystem where various applications can communicate and collaborate efficiently. The mesh network architecture of Wi-SUN FAN supports large-scale deployments, offers scalability to meet the growing number of EVs and other smart devices, and this flexibility makes it suitable for expanding EV charging networks in both urban and rural areas without significantly increasing costs.
Vehicle-to-Grid (V2G) technology is an innovative approach that allows EVs to interact with the power grid, providing benefits such as energy storage and grid stabilization. By integrating V2G capabilities into EVSE solutions, the overall efficiency and sustainability of the charging infrastructure can be enhanced. This technology is particularly important for commercial locations, as the aggregated energy from multiple EVs can significantly impact grid management.
Security is another important topic. When charging stations connect to local networks, security is critical as they are exposed to potential attacks. The security mechanisms of Wi-SUN FAN are based on widely adopted industry standards. Access control is based on IEEE 802.1X and IEEE 802.11i standards, enabling mutual authentication and establishing a security association between the joining node and the Wi-SUN Border Router. Frame security uses the AES-CCM* encryption algorithm from the IEEE 802.15.4 standard, ensuring data confidentiality and authenticity.
Wi-SUN solutions that meet the needs of EV charging stations
For over a decade, Silicon Labs has been committed to developing solutions for industrial and commercial applications, with a long history and outstanding track record in the development of the Wi-SUN standard. Its portfolio includes support for OFDM and FSK, Wi-SUN certified ICs, and a complete set of reference designs and development tools. The high transmit power, best-in-class link budget, Sub-GHz wireless, and mesh networking solutions provided by Silicon Labs deliver stable connections even over long distances and can penetrate obstacles.
Low latency is another key consideration for EV charging station requirements. A system may contain hundreds of charging stations that need to communicate constantly to balance the load. Latency severely impacts system performance, and high latency increases the risk of system overload. The FG25 Wireless SoC supports MR SUN OFDM modulation for Wi-SUN FAN 1.1, achieving data rates up to 2.4 Mbps and low latency.
Beyond the security mechanisms of Wi-SUN FAN, Silicon Labs' solutions also protect devices against sophisticated hardware and software attacks. Its Secure Vault™ feature has achieved PSA Certified Level 3, offering the highest level of security.
Silicon Labs provides comprehensive system solutions for Electric Vehicle Supply Equipment, utilizing Wi-Fi, Matter, Bluetooth Low Energy (BLE), Proprietary RF, and Wi-SUN technologies to meet the needs of both home and commercial locations. These solutions ensure robust wireless connectivity, enabling efficient and secure communication between EV chargers and the power grid. Silicon Labs' solutions boast industry-leading RF performance, energy efficiency, and a strong focus on security. These advantages collectively help device manufacturers create innovative, reliable, and secure EV charging solutions.
Silicon Labs offers numerous related products to meet the needs of EVSE systems. For instance, the EFR32FG23 Sub-GHz Wireless SoC offers long-range, city-wide wireless transmission capabilities, providing industry-leading security and low power consumption, making it an ideal choice for reliable renewable energy solutions. The EFR32FG28 Sub-GHz Wireless + 2.4 GHz BLE SoC is a dual-band SoC that is an ideal solution for IoT applications in smart homes, security, lighting, building automation, and metering.
Furthermore, the EFR32MG24 Series 2 Multiprotocol Wireless SoC is an ultra-low-power, multi-protocol 2.4 GHz SoC with PSA Level 3 security protection, bringing AI/ML and high-performance wireless capabilities to battery-powered devices. Another product, the SiWx917M Wi-Fi 6 + Bluetooth Low Energy 5.4 Wireless SoC, is an ultra-low-power Wi-Fi 6, BLE 5.4, and Matter SoC that provides secure cloud connectivity, control, and OTA updates for renewable energy applications.
Conclusion
Integrating Electric Vehicle Supply Equipment with Wi-SUN FAN networks is a forward-thinking approach to building a more efficient, scalable, and secure EV charging infrastructure. This combination leverages the strengths of both technologies to support the growing EV market and promote the development of a sustainable, connected transportation ecosystem. By utilizing Wi-SUN, EV charging networks can seamlessly interact with smart city applications. The relevant product lines from Silicon Labs will provide cost-effective and future-proof solutions for expanding EV charging infrastructure.