THE CHALLENGE
Design a dual-output DCFC supporting CCS Type-1, CHAdeMO, and Type-2 AC simultaneously with a 15% BOM cost reduction target vs previous generation.
THE SOLUTION
Implemented Two-Level Full-Bridge LLC topology with synchronous rectification. IsoMOV-based SPD design replacing legacy surge protection. SuperCap backup system via LTC3350 for ride-through capability.
RESULTS & OUTCOMES
80+ units deployed across US commercial sites
15% BOM cost reduction achieved
UL 2594 and IEC 61851 certification completed
30% improvement in production throughput
This project required designing a next-generation 240kW DC fast charger capable of simultaneously serving CCS Type-1, CHAdeMO, and Type-2 AC vehicles — while hitting an aggressive 15% BOM cost reduction target relative to the previous generation platform.
Architecture Overview
The power stage uses a Two-Level Full-Bridge LLC resonant converter topology operating at variable frequency across the resonant tank. Synchronous rectification on the secondary side improves efficiency at partial load, where DCFC units spend the majority of their operating time during real-world deployment.
Surge protection was redesigned around IsoMOV hybrid devices, replacing the legacy MOV+GDT stacks. This reduced component count in the SPD circuit by 40% while improving clamping voltage accuracy and passing UL 1449 4th edition requirements.
SuperCap Ride-Through
A supercapacitor backup system using the LTC3350 provides holdup capability during brief grid disturbances — a key requirement for sites without UPS infrastructure. The LTC3350 handles charge balancing across the capacitor stack and communicates system health to the main controller via I²C.
Certification
The platform achieved UL 2594 listing and IEC 61851-1 compliance through a structured pre-compliance and formal test programme. OCPP 2.0.1 was implemented with ISO 15118-2 Plug-and-Charge support, future-proofing the platform for utility-managed charging programmes.
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Eight years of production-proven hardware expertise — from first topology decision to regulatory sign-off.