Powertrain modularity

The report details the results related to the design, fabrication and validation of the compact power modules, including active switches, gate drivers and auxiliary electronics, at a laboratory level conducted as part of the RHODaS project. Thermal degradation and undesirable electrical effects are also studied and presented.

This document provides a comprehensive report on the activities related to the experimental validation of lab-scale power converter prototypes. It includes an analysis of the current standards for power converter testing, drawing on publicly available sources and the expertise of RHODaS partners.

The document also proposes a detailed test plan for High Power Converters (HPC), which are based on Low Power Converter modules. This plan encompasses electrical tests for both Low Voltage (LV) and High Voltage (HV) parts, as well as environmental, mechanical, and safety tests. Additionally, the document reports on laboratory tests to verify basic parameters of Low Power Converters (LPC), such as efficiency, distortion, and Common Mode Voltage (CMV).

The analysis highlights the absence of comprehensive standards for inverter testing, necessitating the search for relevant documents from various testing fields. Due to the high voltage levels considered in the DC/AC converter, of at least 1000 VDC Bus, it is necessary the adaptation of research methodologies in cases where direct references are lacking. This process requires substantial knowledge and experience in test systems and application of standards.

The conclusions drawn from these activities are expected to support future design, optimization and recommendations, focusing on further improvements in power converters and the use of standards specifically adapted for them in automotive applications.

This deliverable reports the selection of the optimum power devices for implementing the SCAPE high-voltage switching cells, after a literature review and commercial availability check. In addition to suitable electrical characteristics, the selection of candidates considered the suitability and availability of bare-die components for their subsequent chip embedding process. Two SiC MOSFET references have been selected and samples have been obtained for an initial test campaign (GeneSiC G4R12MT07. 750V – 12 mΩ and Wolfspeed CPM3-0650-0015A. 650V – 15 mΩ). For the development of the low-voltage switching cells of the auxiliary SCAPE converters, GaN HEMTs from EPC will be selected. The deliverable also includes a prospective and literature review about power device emerging technologies. 

This deliverable presents the design, validation, and testing of the RHODaS high‑power hybrid T‑type multilevel inverter. Chapter 2 explains the overall architecture of the inverter, including sensors, modular power stages, mechanical structure, housing, and integration. The first design of the power stage did not meet the electrical and thermal requirements; therefore, several improvements were introduced in the final stage, which are also described in this chapter. Both iterations, the initial and the final design, are documented to highlight the evolution of the system. Chapter 3 explains the initial T‑type design and the challenges encountered with the first GaN transistors, such as voltage limitations, short‑circuit behaviour, and reliability issues. Chapter 4 explains the initial inverter tests, including switching behaviour and operation at different load points, which were performed to ensure proper functionality. Finally, chapter 5 defines the comprehensive high‑power inverter tests, covering efficiency, thermal performance, and maximum power capability, with final validation to be conducted at BOSMAL’s mechanical testing laboratory. In conclusion, the deliverable documents the progression from an initial design with critical shortcomings to a robust final inverter prototype, achieving a power density of 58.6 kW/l. The initial tests confirm that the converter is both reliable and capable of operating in line with the project specifications, reaching efficiencies of up to 99%. Nevertheless, the definitive validation of the converter will be conducted at BOSMAL, where the comprehensive test procedures defined in this deliverable will be applied to ensure full compliance with the project requirements. 

This deliverable reports on the switching tests validating the driver design of the highpower 150 kW hybrid T-Type converter for the RHODaS project. The study addresses the challenges of integrating Wide Band Gap (WBG) semiconductors, specifically Gallium Nitride (GaN) and Silicon Carbide (SiC), in high-voltage configurations to enhance efficiency. While the initial prototype faced reliability issues, a redesign utilising GaN Systems devices (GS66516B) and negative turn-off voltage successfully mitigated parasitic turn-on risks. Experimental analysis confirmed robust operation up to 1000 V. However, high commutation loop inductance (≈100 nH) necessitated limiting switching rise times to 70100 ns via adjusted gate parameters (Rgate=22 Ω, Cgate=4.7 nF). This adjustment prioritised reliability over minimal switching losses. Regarding control, whilst advanced CBPWM and SPWM strategies were implemented in the System on Chip (SoC), some constraints prevented their full experimental validation. Thus, standard Space Vector Modulation (SVPWM) will be employed for final testing.  In conclusion, the project delivered a robust GaN stage capable of 1000 V operation, though the validation of custom modulation techniques remains pending. 

The RHODaS Webinar Series presents four interconnected sessions exploring the latest European research on next-generation electric powertrain technologies. Hosted by the RHODaS consortium under the Horizon Europe framework, funded by ‪the European Commission‬ and as part of the E-VOLVE Cluster, the webinar series will feature insights from the RHODaS, SCAPE, ‪Maxima‬ and EM-TECH projects, bringing together leading experts in power electronics, digital systems, and sustainability. Each webinar focuses on a specific technological domain critical to the electrification of transport — from component design and thermal management to digital intelligence and circularity. Together, they illustrate how European research is transforming electric mobility through efficiency, reliability, and environmental responsibility. 

This opening session delves into the design of hybrid wide bandgap converters and modular architectures for electric vehicles. Presentations from RHODaS and SCAPE will discuss innovative SiC/GaN topologies, design challenges such as parasitic inductances and layout constraints, and scalable approaches for vehicle power conversion systems.