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Multiphysics analysis and experimental validation of acoustic noise reduction in a high pole count, high power, switched reluctance machine (SRM), through skewing are explored in detail in this work. An iterative optimization strategy covering electromagnetic, structural, and thermal domains is proposed to investigate the effect of different skewing methods and angles on a 24-stator slot/16-rotor pole (24/16) SRM rated at 100 kW. The contributions of this work are twofold. First, electromagnetic impact, considering average torque, torque ripple, radial and tangential air gap forces, of symmetric and asymmetric skewing on stator and rotor is studied in this work. Second, the impact of skewing methods on acoustic noise and vibration performance is studied and presented in detail. The study reveals that skewing both the stator and rotor by the same amount has superior electromagnetic performance over other types of skewing. Multiphysics simulations conducted, predict a 10.5 dBA reduction in the acoustic noise, compared to a baseline design with no skew, for an optimized rotor-stator skewing angle of 13.75°. Finally, 100 kW prototypes of the baseline and the optimized skewed SRM were constructed and subjected to wide speed range testing. Simulation and test results closely follow each other and validate the effectiveness of the proposed skew design in mitigating acoustic noise and vibration in high pole count SRMs. [ABSTRACT FROM AUTHOR]

Switched reluctance machine (SRM) drive requires a large dc-link capacitor due to the low-frequency harmonics in dc-link current, which is generated during the current commutation between phases. Installing a bulky capacitor bank in the drive has a significant impact on the cost and the overall volumetric power density of the drive. This article analyzes the dc-link current ripple in SRM drive and proposes a control algorithm to reduce the dc-link current ripple while maintaining the machine performance. The proposed algorithm extracts the ripple components from the dc-link current using a high-pass filter. The controller ensures ripple energy circulation between the phases and reduces the pulsating energy requirement from the dc supply. The dc-link ripple is suppressed at a wide speed range of operation to enable efficient and reliable drive operation without adding any external hardware system. Simulation and experimental results are provided to prove the effectiveness of the proposed control technique for both steady-state and transient conditions. [ABSTRACT FROM AUTHOR]

With growing interest in electrification in automotive industries, the selection of suitable electric machine types based on application requirements is most important. In this article, three electric machine types, axial flux machine, interior permanent magnet (IPM) machine, and switched reluctance machine, are compared systematically to find the best candidate to drive engine accessories in a hybrid truck. These machine types are designed and optimized to meet the application-oriented design requirements and constraints. An extensive Pugh matrix is created where each machine type is scored based on efficiency range, cost, volumetric power density, gravimetric power density, acoustic noise and stress on the rotor, fault tolerance, heat rejection, and manufacturability. Each Pugh matrix component is assigned to a priority-based weighting, based on the application demand, to determine an accumulated score for each machine topology. A full-scale prototype of the best performing machine type is built and tested. Experimental results validate the multiphysics conclusions drawn in the work. [ABSTRACT FROM AUTHOR]