With vehicle electrification and employment of X-by-wire technology, mechanical systems are being replaced by motor drives which improve the efficiency and performance of vehicular systems. However, motor drives have a lower power density and reliability compared to mechanical solutions. Multi-motor drives have the potential of mitigating both these drawbacks. In this paper, a state-of-the-art review of multi-motor drives and their application to vehicular systems is carried out. Firstly, the case of multi-motor systems in automotive applications is laid out by presenting the different vehicular systems comprising multiple motors. Secondly, multi-motor drive topologies with improved power density, reliability and fault tolerance capabilities are thoroughly analyzed. Finally, the topologies are assessed and compared in the context of automotive applications. The assessment verifies that multi-motor drives allow for fault tolerant and cost-effective solutions that are suitable for automotive applications.

This article investigates and validates the applicability of the recently developed stray voltage capture (SVC) ultra-fast short-circuit (SC) detection method and its extended version (ESVC) to fault-tolerant multi-motor drives. As these methods are system-based, a fault localization algorithm is also developed. Simulation analysis of the inverter stray inductances shows additional challenges for the SVC method making it hard to achieve ultra-fast SC detection. The ESVC method is slower but overcomes these challenges. The methods are adapted for a 400 V 6-phase Silicon Carbide based inverter equipped with a 2-level turn-Off hardware protection scheme. Fault under load and hard switching fault tests are performed showing the effectiveness of the ESVC in fast (smaller than 330 ns) and reliable SC detection and protection for SiC MOSFETs. The fault localization algorithm is also validated showing a localization speed smaller than 20 μs.