Powertrain modularity

This document presents the analysis, development, and testing of advanced active gate drivers (AGD) for high-power, high-frequency wide bandgap (WBG) devices, specifically focusing on Gallium Nitride (GaN) transistors. It aims to improve the performance of power converters by reducing circuit losses, overshoots, and electromagnetic interference (EMI) through a novel gate driving approach based on high-frequency PWM. The findings and methodologies are intended to enhance the efficiency and reliability of power electronic systems, particularly in high-power applications like those in the RHODaS project.

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 paper presents a new gate-driving profile to mitigate the switching issues caused by high-speed operation of GaN transistors in on-off transitions. The concept consists of modifying the primary PWM signal applied to the GaN transistors to an appropriate voltage profile, which changes the gate-source voltage behaviour in the critical stage of the GaN transitions. The gate-driving concept is evaluated on LTspice, and the results show the reduction of ringing and overshoots when applying the proposal while maintaining tolerable power losses.

This work presents an experimental study of a hybrid T-type converter using wide-bandgap (WBG) devices, combining the low switching losses of gallium nitride (GaN) with the high-voltage capability of silicon carbide (SiC). Furthermore, an adaptive level-shift algorithm is introduced, enabling operation in both two- and three-level modes, improving fault tolerance and current capability. Experimental validation demonstrates high efficiency, minimal EMI impact at high switching frequencies, and improved THD, confirming the converter as a robust solution for high-performance applications.

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.

The Horizon Europe projects EM-TECH and HighScape propose innovative solutions for electric traction machines and their WBG-based drives and components, to achieve higher energy efficiency, reduced volume and mass, as well as reduced cost. This paper outlines the main innovations of EM-TECH and HighScape, targeting a wide range of vehicle applications, including passenger cars and commercial vehicles. Specifically, EM-TECH deals with: i) modular designs of on-board axial flux machines (AFMs) for reducing the implementation costs of scalable centralised powertrains for electric axle (e-Axle) solutions; ii) in-wheel motors (IWMs) integrated with electric gearing, for expanding the high efficiency region of electric corner (e-Corner) powertrains; and iii) the use of permanent magnets deriving from recycling processes to improve sustainability. In parallel, HighScape targets the physical and functional integration of the power electronics of WBG-based traction inverters, onboard chargers, DC/DC converters, and electric drives for auxiliaries and actuators.