Problem
A leading provider of EV charging solutions faced significant challenges integrating reliable WiFi connectivity into their next-generation charging stations. The demanding environment of charging stations – often exposed to electrical noise and requiring secure, consistent communication – necessitated a robust solution. Initial attempts with readily available WiFi modules proved inadequate, exhibiting inconsistent performance under load and failing preliminary EMC testing. A critical need existed for a solution capable of handling high data throughput for remote monitoring, firmware updates, and payment processing, while also adhering to stringent regulatory requirements. The pressure to deliver a stable, secure, and certifiable product within a tight timeframe was substantial.
Solution
We developed a custom WiFi solution leveraging the Murata 2BC/2AE WiFi module as its core component. Recognizing that simply dropping in a module wouldn’t suffice, our approach centered on a comprehensive design encompassing hardware, software, and proactive regulatory compliance. We applied our deep expertise in RF engineering, electromagnetic compatibility (EMC) and interference (EMI) mitigation, and embedded Linux development to deliver a fully integrated and production-ready system. From the outset, we treated certification as an integral part of the design process, anticipating and addressing potential issues early on.
Implementation
The project involved a multi-faceted implementation strategy:
- Hardware Design & Layout: We meticulously crafted the RF circuitry, focusing on precise impedance matching, effective filtering, and strategic shielding to maximize performance and minimize unwanted emissions. The PCB layout was carefully optimized, with a focus on controlled impedance routing, robust ground planes, and component placement to ensure signal integrity and reduce potential EMI sources.
- EMC/EMI Mitigation: Throughout the design cycle, we conducted extensive simulations and rigorous pre-compliance testing. We employed techniques like ground plane stitching, differential signal routing, and careful component selection to suppress both conducted and radiated emissions. Ferrite beads and common-mode chokes were strategically implemented to filter noise on both power and data lines, effectively mitigating interference.
- Linux Kernel Integration: We developed a bespoke Linux kernel module and device tree overlay specifically tailored to the Murata 2BC/2AE module. This involved adapting the driver, optimizing power management for efficient operation, and seamlessly integrating the module with the existing networking infrastructure. We ensured full compatibility with a current, long-term support (LTS) Linux kernel.
- Certification Support: We meticulously prepared all required documentation and test plans for relevant certifications (e.g. CE). We conducted thorough pre-compliance testing, proactively identifying and resolving potential issues to ensure a smooth and successful certification process.
Results
The resulting solution delivered a highly reliable and certifiable WiFi connection for the EV charging infrastructure. The product successfully passed certification on the first submission, significantly accelerating time-to-market. Comprehensive EMC/EMI testing confirmed exceptional performance, comfortably exceeding industry standards. The custom Linux kernel driver provided a stable, efficient, and well-integrated interface, enabling seamless communication and remote management capabilities. The solution demonstrably improved connection stability and data throughput compared to previous iterations, resulting in a more robust and user-friendly charging experience. This project showcased our ability to deliver a complete, certified, and optimized WiFi solution, from initial concept to production deployment.
