The deliverable D5.1 presents the final prototype of the RHODaS high‑power hybrid T‑type multilevel inverter, documenting its design, integration, and validation procedures. The report provides a detailed description of the inverter architecture, including sensors, modular power stages, mechanical structure, housing, and system integration. The initial design of the power stage failed to meet the electrical and thermal requirements, necessitating several improvements in the final version. These challenges were addressed through iterative redesigns that included enhanced thermal management, bottom-cooled GaN devices, and the addition of copper plates soldered to the PCBs to improve heat spreading. The redesign simplified integration, improved thermal conductivity, and ensured the robustness of the final prototype.
Preliminary testing of the initial inverter assessed switching behaviour and operation across different load points to verify basic functionality. Following the redesign, comprehensive high-power tests were performed on the final prototype, including efficiency measurements, thermal performance evaluation, and maximum power capability verification. The prototype achieved efficiencies of up to 99% across various load points in both two-level and three-level operation, while thermal measurements indicated GaN temperatures of approximately 82 °C during a sustained 10-minute test at 60 A. The inverter reached a power density of 58.6 kW/l, demonstrating a high level of performance consistent with project targets.
The deliverable also defines validation scenarios and procedures in alignment with relevant automotive standards, including ISO 21782‑3. These procedures will be applied during final validation at BOSMAL’s mechanical testing laboratory to ensure that the converter meets all project requirements. Despite the delays introduced by the redesign process, the final prototype represents a reliable and functional platform, addressing the mechanical, thermal, and electrical challenges identified in the initial design. The results confirm that the RHODaS hybrid T‑type power converter is capable of operating reliably at high power levels and provides a solid basis for full-scale validation and deployment in the project context.
Access the full deliverable here
