Reliability and Cost Assessment of Fault-Tolerant Inverter Topologies for Multi-Motor Drive Systems

Automotive x-by-wire (XBW) systems require the development of cost-effective, compact, and reliable motor drive solutions. With the multiport inverter architecture, it is possible to improve on these aspects. In this paper inverter fault tolerance strategies are first reviewed, and proper ones are selected. The strategies are then applied to single-input multi-output (SIMO) inverter topologies and 2, 3 and 4 motor systems are considered. Next, the cost and reliability of the resulting topologies are assessed and compared. Finally, the suitability of these topologies considering automotive applications requirements is discussed. It was found that the leg redundant strategy is the most suitable one and that the cost and reliability are both improved when that strategy is applied to SIMO topologies. The improvements are also more significant for a higher number of motors. The conventional combined topology was found to be the best for general XBW systems but in special applications the shared-leg topology can be a better solution.