Driving the future of EV charging: narrowband power line communication (NB-PLC)

Here, Zeev Collin, CEO of Semitech Semiconductor, explores how NB-PLC is revolutionising energy management, particularly in vehicle-to-home (V2H) and vehicle-to-grid (V2G) applications.

Revolutionising energy management with V2H and V2G technologies

The advent of vehicle-to-home (V2H) has unlocked a new dimension in energy management. With V2H, EVs can act as supplementary power sources, discharging stored energy into household electrical systems during peak demand, outages, or strategic energy-saving periods. This capability not only enhances grid stability but also empowers homeowners to optimise electricity costs. Vehicle to grid (V2G) takes this concept further by enabling the energy providers to actively manage the load on the grid and seamlessly administer demand response programmes.

Why NB-PLC is the perfect fit for EV chargers

NB-PLC offers a solution to meet the complex communication needs of EV chargers. By leveraging existing power lines for data transmission, NB-PLC eliminates the need for additional wiring, reducing installation costs and complexity. Its robust and reliable performance makes it particularly suitable for the demanding environment of EV charging stations.

NB-PLC operates over existing power lines within a frequency range of 3kHz to 500kHz. Unlike broadband PLC technologies, such as GreenPHY, NB-PLC offers slower but more stable connections, supporting reliable communication over long distances, even in environments with high interference. Its ability to use existing infrastructure reduces installation and operational costs.

Integrating NB-PLC into EV chargers offers several key benefits:

• Cost efficiency: because NB-PLC uses existing power line infrastructure, it eliminates the need for separate communication cabling, reducing installation and maintenance costs
• Reliability: NB-PLC's resilience to noise and interference on power lines makes it ideal for high-reliability applications
• Long-range capability: NB-PLC can communicate over long distances, even in dense environments like parking lots or urban areas
• Co-existence: NB-PLC can co-exist with other PLC technologies, such as GreenPHY and the associated 15118 protocol used for EV/Charger communication, and HomePlug AV used for in-home TV/Entertainment systems
• Standard compliance: NB-PLC protocols, like G3-PLC, align with global standardised communication protocols for smart grids, such as IEC 61850 and Open Charge Point Protocol (OCPP), supporting compatibility and interoperability between chargers on a public network and connectivity between chargers and charger management systems

Applications of NB-PLC in EV chargers

Load management and vehicle-to-grid integration

• NB-PLC enables real-time communication between EV chargers and grid operators, supporting demand response programmes. EV chargers equipped with NB-PLC can coordinate with grid frequency and voltage management protocols, assisting in grid stability, optimising energy consumption and preventing grid overloads during peak hours.

Vehicle-to-home integration

• Even without full V2G deployment, NB-PLC enables seamless two-way data communication between EV chargers and Home Energy Management Systems (HEMS) without additional wiring. This enables the HEMS to monitor in real-time the EV’s charge state and manage the battery discharge based on energy needs or grid conditions.
• Active EV charge management enables V2H systems to discharge during high-rate peak demand times and charge during low-rate periods, reducing electricity costs for the homeowner. It also optimises the timing and extent of battery discharge to ensure the EV retains sufficient charge for transportation needs.
• In the event of a power outage, NB-PLC-enabled chargers can activate V2H mode, supplying critical household circuits with backup power.
• For home chargers located out of home Wi-Fi range, NB-PLC provides an economic convenient alternative for connecting to the home network by adding an NB-PLC bridge.

Inter-charger communication and aggregation

• In shared charging setups, such as apartment buildings, car parks, or fleet operations, inter-charger communication optimises power distribution and prioritises charging for vehicles with urgent needs.
• Inter-charger communication consolidates data from multiple chargers, simplifying management and enabling seamless integration with cloud-based systems from a single aggregation point.

User authentication and billing

• NB-PLC supports secure user authentication and authorisation, and transmits billing data to backend systems, assuring accurate real-time cost calculations.

Remote monitoring and diagnostics

• NB-PLC allows remote monitoring of the operational status of EV chargers, enabling fault detection, firmware updates, and predictive maintenance to reduce downtime and extend charger lifespan. Chargers can send real-time alerts and diagnostic data to service operators, enhancing reliability and safety.

Unlocking seamless connectivity: mastering integration with application layer protocols

NB-PLC provides a physical communication layer between EV chargers, charge points, and possibly a central data aggregator. It effectively combines with application layer protocols within the EV charging infrastructure for communication between chargers and a charging point management system (CPMS), such as the Open Charge Point Protocol (OCPP). Through OCPP, charging stations communicate essential data such as charging status, fault notifications, energy usage, and billing information, as well as manage functions like authentication, authorisation, and real-time monitoring. Developed by the Open Charge Alliance (OCA), OCPP is widely adopted by charging network operators, equipment manufacturers, and utility companies around the world.

By using NB-PLC as the data transmission channel, the charging infrastructure can rely on OCPP to handle higher-level protocols. This integration enables seamless data exchange over NB-PLC, facilitating the central monitoring and management of charge points through OCPP. For example, NB-PLC transmits OCPP messages from the charger to the CPMS, allowing the CPMS to manage sessions, update firmware, and send status commands.

NB-PLC enables aggregation of data from multiple chargers through a single communication pathway, which is then relayed to the CPMS using OCPP. This combined approach allows for efficient load balancing, remote monitoring, diagnostics, and firmware updates across multiple EV chargers, controlled via OCPP at the CPMS level.

Technical considerations

While NB-PLC offers significant advantages for EV chargers, optimal system performance requires consideration of all system aspects, such as the following:

• Interference and noise: despite NB-PLC’s robust design, significant interference from other power line devices or heavy equipment could still impact data transmission quality. Mitigating strategies, such as robust communication modes, should be implemented in high-interference environments.
• Limited bandwidth: NB-PLC's data rates may not be sufficient for applications requiring high data throughput (>500kbps). Careful planning of communication intervals and data packets is essential to optimise bandwidth utilisation.
• Compliance with standards: ensuring adherence to communication standards and regional regulations is essential for achieving interoperability across diverse EV infrastructure.

Conclusion: the value of NB-PLC to V2H and V2G

NB-PLC provides significant value to V2H and V2G applications by enabling seamless, cost-effective, and reliable communication between EV chargers, utilities, HEMS, and EVs. Through NB-PLC, EV chargers can dynamically manage energy usage, support load balancing, provide emergency backup power, optimise energy costs, enable user authentication, and support remote diagnostics and safety monitoring. As V2H and V2G technologies advance, NB-PLC’s ability to leverage existing power lines for dependable, low-cost communication makes it an essential tool in building smarter, more resilient HEMS and a more efficient EV charging ecosystem.

Semitech’s NB-PLC technology exemplifies these benefits by offering noise-resilience, long-range capabilities, standards compliance, and advanced communication features. Enabled by Semitech’s reliable and cost-effective NB-PLC, EV chargers can become a key part of smart energy systems, enhance grid stability, support future-proof integration with V2H and V2G systems and contribute to the broader adoption of EVs and sustainable energy solutions.