Multiharmonic Torque Suppression for Single-Phase Open-Circuit Fault-Tolerant Operation of Brushless Dual Rotor Machines With Neutral Points Connection

Brushless dual rotor machines (BLDRMs) emerge as promising solutions for electric vehicles and aerospace propulsion applications. Given stringent reliability and safety requirements, effective fault-tolerant control is critical. With two sets of three-phase windings, each having its own neutral point, the performance of BLDRM under single-phase open-circuit fault can be significantly enhanced by connecting the neutral points; however, it induces zero-sequence currents, which excite complex integer- and fractional-order torque ripples in faulty and healthy windings, respectively. This issue precludes direct application of conventional harmonic current injection methods developed for a single winding set. Therefore, this paper proposes a zero-sequence current model-based torque compensation active disturbance rejection control (ZSCMTC-ADRC) scheme to effectively mitigate the torque ripples, which generates adaptive harmonic current references. Especially, the frequency characteristics of zero-sequence currents and the resulting multi harmonic torque components in two winding sets of BLDRM are firstly theoretically analyzed in the paper. Furthermore, a proportional-integral-resonant (PIR) controller tuned to specific harmonic frequencies is implemented to ensure accurate current tracking. Experimental validation on a BLDRM drive platform confirms the efficacy of the proposed fault-tolerant strategy.