Delta-inverter fed fractional-slot six-phase brushless DC motors Analysis, control, and fault-tolerance capability

Purpose - This paper deals with the analysis, the modeling, the control and the fault-tolerance capability of a three-switch inverter (TSI, also known delta-inverter) fed fractional-slot six-phase brushless DC motor (BDCM) drive. Design/methodology/approach - Following the presentation of the advantages of multi-phase fractional-slot brushless machines and the possibility of their association to TSI, the analysis of the operating sequences as well as the modeling of a TSI fed six-phase BDCM drive are developed. Then, a dedicated control strategy of such a drive is synthesized. Finally, a case study is simulated considering both transient behaviour during the start-up of the BDCM as well as a steady-state one under healthy and faulty operations. Findings - It has been found that the 60-electrical degree shift between the six phases of the BDCM makes it simple to achieve its operating sequences with its armature fed by a TSI, considering a suitable anti-parallel connection of the six phases. Practical implications - Crucial cost benefits associated with improved compactness, reliability, and fault-tolerance capability could be gained thanks to the integration of TSI fed six-phase BDCM drives in large-scale production industries, such as the automotive one. Originality/value - The paper proposes an analysis of the operating sequences as well as the fault-tolerance capability of TSI fed six-phase BDCM drives.