@article{islam_mikail_kabir_husain_2022, title={Torque Ripple and Radial Force Minimization of Fractional-Slot Permanent Magnet Machines Through Stator Harmonic Elimination}, volume={8}, ISSN={["2332-7782"]}, DOI={10.1109/TTE.2021.3104758}, abstractNote={This article proposes a torque ripple minimization strategy based on minimizing interactive space harmonics of fractional-slot permanent magnet (PM) machines using a space-shifted wye–delta stator winding. A radial force analysis has also been carried out, which showed a substantial reduction in the second-order mode for these space-shifted wye–delta wound machines; this will improve the noise and vibration performance. The effectiveness of the proposed method is shown by analyzing the performances of a low-power surface-mounted permanent magnet (SPM) machine for the electric power steering (EPS) applications and a high-power interior permanent magnet (IPM) machines for the hybrid electric vehicle (HEV) applications on the 12-slot/10-pole (12 S/10 P) configuration. The proposed winding doubles the stator slot number of the base model, and as a result, the base 12 S/10 P configuration becomes 24-slot/10-pole (24 S/10 P) combination. Compared with the existing ripple minimization techniques of magnet shaping or rotor skewing, the proposed stator winding-based strategy achieves better torque ripple performance and magnet utilization leading to an improvement in average torque while reducing the amplitude of the low-order radial force. A 10-pole SPM machine has been built and tested for experimental validation of both the concept and the finite element analysis (FEA) simulation results.}, number={1}, journal={IEEE TRANSACTIONS ON TRANSPORTATION ELECTRIFICATION}, author={Islam, Md Sariful and Mikail, Rajib and Kabir, Md Ashfanoor and Husain, Iqbal}, year={2022}, month={Mar}, pages={1072–1084} }
 @article{husain_ozpineci_islam_gurpinar_su_yu_chowdhury_xue_rahman_sahu_2021, title={Electric Drive Technology Trends, Challenges, and Opportunities for Future Electric Vehicles}, volume={109}, ISSN={["1558-2256"]}, DOI={10.1109/JPROC.2020.3046112}, abstractNote={The transition to electric road transport technologies requires electric traction drive systems to offer improved performances and capabilities, such as fuel efficiency (in terms of MPGe, i.e., miles per gallon of gasoline-equivalent), extended range, and fast-charging options. The enhanced electrification and transformed mobility are translating to a demand for higher power and more efficient electric traction drive systems that lead to better fuel economy for a given battery charge. To accelerate the mass-market adoption of electrified transportation, the U.S. Department of Energy (DOE), in collaboration with the automotive industry, has announced the technical targets for light-duty electric vehicles (EVs) for 2025. This article discusses the electric drive technology trends for passenger electric and hybrid EVs with commercially available solutions in terms of materials, electric machine and inverter designs, maximum speed, component cooling, power density, and performance. The emerging materials and technologies for power electronics and electric motors are presented, identifying the challenges and opportunities for even more aggressive designs to meet the need for next-generation EVs. Some innovative drive and motor designs with the potential to meet the DOE 2025 targets are also discussed.}, number={6}, journal={PROCEEDINGS OF THE IEEE}, author={Husain, Iqbal and Ozpineci, Burak and Islam, Md Sariful and Gurpinar, Emre and Su, Gui-Jia and Yu, Wensong and Chowdhury, Shajjad and Xue, Lincoln and Rahman, Dhrubo and Sahu, Raj}, year={2021}, month={Jun}, pages={1039–1059} }
 @article{chattopadhyay_islam_boldea_husain_2021, title={FEA Characterization of Bi-Axial Excitation Machine for Automotive Traction Applications}, DOI={10.1109/IEMDC47953.2021.9449514}, abstractNote={Bi-axial excitation generator for automobiles (BEGA) machines are ideally suitable for unity power factor at the base speed which would give the best power density and lowest cost for a traction-motor inverter system. In this paper, three different designs of bi-axial excitation motors are presented: One employing rare-earth free ferrite magnets and two employing NdFeB magnets. The permanent magnets are oriented along the q-axis and are used to compensate the stator flux in order to achieve higher power factor. This reduces the required inverter size thus bringing down the overall system cost. The flux compensation is analyzed using 2D FEA and the motor performances are compared to other commonly used traction motor topologies.}, journal={2021 IEEE INTERNATIONAL ELECTRIC MACHINES & DRIVES CONFERENCE (IEMDC)}, author={Chattopadhyay, Ritvik and Islam, Md Sariful and Boldea, Ion and Husain, Iqbal}, year={2021} }
 @article{islam_mikail_husain_2021, title={Field Weakening Operation of Slotless Permanent Magnet Machines Using Stator Embedded Inductor}, volume={57}, ISSN={["1939-9367"]}, DOI={10.1109/TIA.2021.3061043}, abstractNote={This article presents a comprehensive design methodology to improve the field weakening (FW) operation of low inductance slotless permanent magnet synchronous machines (PMSMs). The proposed concept of using a stator embedded inductor integrated with the torque producing machine windings helps achieve a wide constant power speed range (CPSR) and a desired torque/speed characteristics. Key performance parameters including system efficiency and PWM induced current ripple are summarized for scenarios with and without the embedded inductor in the entire operating range using 2-D finite element analysis. The concept helps to achieve the desirable extended torque/speed range. It also helps to improve the efficiency beyond the base speed operation for a high speed, high power machine. In addition to achieving desired CPSR, this method also helps to reduce the PWM induced current ripple, short circuit current, and current ripple induced core losses. A slotless machine with the integrated embedded inductor has been designed following the proposed design guidelines to extend the CPSR, and a prototype motor has been built to validate the simulation results with the experimental results.}, number={3}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Islam, Md Sariful and Mikail, Rajib and Husain, Iqbal}, year={2021}, pages={2387–2397} }
 @article{islam_agoro_chattopadhyay_husain_2021, title={Heavy Rare Earth Free High Power Density Traction Machine for Electric Vehicles}, DOI={10.1109/IEMDC47953.2021.9449585}, abstractNote={A compact, heavy rare earth free permanent magnet synchronous machine with a volumetric power density of 50kW/liter is designed for electric traction applications. This is facilitated by innovations in the stator winding topology, magnet arrangement, and cooling technique. A 24-slot/10-pole dual three-phase asymmetric winding layout is adopted to improve power density, reduce harmonic losses, and improve fault tolerant capabilities. Furthermore, a novel segmented V-type magnet arrangement is proposed to address the demagnetization issues of the heavy rare earth free magnets under extreme temperatures and negative electromagnetic fields. An extensive finite element analysis has been conducted and results are presented to show the electromagnetic and demagnetization performance as well as the thermal capabilities and structural integrity of the proposed design.}, journal={2021 IEEE INTERNATIONAL ELECTRIC MACHINES & DRIVES CONFERENCE (IEMDC)}, author={Islam, Md Sariful and Agoro, Sodiq and Chattopadhyay, Ritvik and Husain, Iqbal}, year={2021} }
 @article{islam_chowdhury_shrestha_islam_husain_2021, title={Multiload Point Optimization of Interior Permanent Magnet Synchronous Machines for High-Performance Variable-Speed Drives}, volume={57}, ISSN={["1939-9367"]}, DOI={10.1109/TIA.2020.3040141}, abstractNote={Multiobjective and multiload point design optimization of an interior permanent magnet (IPM) synchronous machine using a global response surface method to achieve low torque ripple with high average torque over the entire speed range is presented in this article. The approach consisting of a set of design steps and multiobjective optimization to obtain high-performance electric machines with optimum usage of rare-earth materials for mass production is presented. The design optimization has been applied to a 12-slot eight-pole IPM machine with two different rotor structures to arrive at the optimized design for a variable-speed high-performance application. Motor parameters are extracted under different load conditions to predict the torque/speed performance of the motors. The proposed design approach provides a machine design with maximized output torque, improved torque density, lower torque ripple, and optimum usage of rare-earth materials. Finally, the finite-element-based modeling results are validated with the experimental results.}, number={1}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Islam, Md Sariful and Chowdhury, Mazharul and Shrestha, Amina and Islam, Mohammad and Husain, Iqbal}, year={2021}, month={Jan}, pages={427–436} }
 @article{islam_kabir_mikail_husain_2020, title={A Systematic Approach for Stator MMF Harmonic Elimination Using Three-Layer Fractional Slot Winding}, volume={56}, ISSN={["1939-9367"]}, DOI={10.1109/TIA.2020.2984195}, abstractNote={A systematic approach based on a novel space-shifted three-layer winding (SSTLW) to eliminate both the sub- and superharmonics of fractional slot concentrated winding ac machines is presented. In this proposed three-layer fractional slot winding, the number of turns in one layer and the relative positions of other two layers are optimized to cancel subharmonics. The cancellation of superharmonics is achieved through series connection of two SSTLWs through effective doubling of the number of slots. The cancellation of the dominant sub- and superharmonics using this approach leads to reducing the total harmonic distortion, torque ripple, PM eddy current loss, and rotor core loss, while simultaneously improving power factor and saliency ratio. The proposed design methodology and ensuring improvements have been validated through finite element analysis for the widely used 12-slot/10-pole and 18-slot/14-pole permanent magnet synchronous machine (PMSM) configurations. A prototype three-layer winding is built for a 10-pole PMSM to validate the simulation results experimentally.}, number={4}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Islam, Md Sariful and Kabir, Md Ashfanoor and Mikail, Rajib and Husain, Iqbal}, year={2020}, pages={3516–3525} }
 @article{islam_husain_ahmed_sathyan_2020, title={Asymmetric Bar Winding for High-Speed Traction Electric Machines}, volume={6}, ISSN={["2332-7782"]}, DOI={10.1109/TTE.2019.2962329}, abstractNote={A new asymmetric bar winding concept along with the analysis and benefits for high-speed traction electric machines is presented. The objective is to reduce the ac losses, especially at high speeds, utilizing optimized and asymmetric conductor heights within a slot for bar-wound stators. Detailed winding diagram, height optimization, ac loss analysis, and thermal performance are presented for both symmetric, i.e., conventional, and asymmetric bar windings. The proposed idea is validated using the closed-form analytical equation and 2-D time-stepped finite-element analysis (FEA). A substantial reduction of ac losses and improvement in continuous power over the wide operation range is achieved as demonstrated for a 12-pole, 100-kW high-speed (15 000 r/min) PM traction machine. Thermal performance analysis using forced liquid cooling is also included. The design and analysis methodology is presented to support high-speed traction electric machine designers meet the ever-increasing demand on efficiency and performance with bar-type windings.}, number={1}, journal={IEEE TRANSACTIONS ON TRANSPORTATION ELECTRIFICATION}, author={Islam, Md Sariful and Husain, Iqbal and Ahmed, Adeeb and Sathyan, Anand}, year={2020}, month={Mar}, pages={3–15} }
 @article{islam_kabir_mikail_husain_2020, title={Space-Shifted Wye-Delta Winding to Minimize Space Harmonics of Fractional-Slot Winding}, volume={56}, ISSN={["1939-9367"]}, DOI={10.1109/TIA.2020.2975766}, abstractNote={A space-shifted wye–delta winding for fractional-slot concentrated winding (FSCW) is proposed that can simultaneously cancel both sub- and super-order harmonics of its stator MMF. The new winding concept proposes two sets of three-phase windings by doubling the number of stator slots connected in the wye–delta configuration. These two winding sets are shifted in space with respect to each other and are connected in series. The wye–delta configuration eliminates subharmonics and enhances the torque-producing component, whereas their relative shifting angle eliminates the dominant higher order harmonics to provide a cleaner and enhanced MMF spectrum. In FSCW motors, dominant space harmonics other than the torque-producing component give rise to undesirable losses in the magnet and rotor core. The efficacy of the proposed method is demonstrated through its stator MMF, harmonic spectrum, and motor performance using finite-element analysis. The application of the proposed winding to a permanent magnet (PM) machine showed dominant sub- and super-order harmonics cancellation, total harmonic distortion reduction, and magnetic loss reduction along with torque density and power factor improvements. A prototype PM machine is built, and the performance of the proposed concept is verified experimentally.}, number={3}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Islam, M. D. Sariful and Kabir, Md Ashfanoor and Mikail, Rajib and Husain, Iqbal}, year={2020}, pages={2520–2530} }
 @article{islam_mikail_husain_2019, title={Slotless Lightweight Motor for Aerial Applications}, volume={55}, ISSN={["1939-9367"]}, DOI={10.1109/TIA.2019.2935055}, abstractNote={A slotless, lightweight permanent-magnet (PM) motor with high pole count is designed and analyzed for a drone system that requires four motors of 0.5 kW each for a 2-kW propulsion power to attain the required torque–speed profile. The design optimization was carried out using finite-element analysis that lead to a slotless stator with outer rotor Halbach PM configuration achieving high power density, zero cogging torque, low torque ripple, sinusoidal back electromotive force, and good system efficiency. The Halbach configuration is found to have superior power density and torque ripple over the conventional concepts for the aerial applications. The power density and efficiency of the slotless motor can be enhanced through the use of nonconventional thermoplastic material and Halbach segmentation. The resulting low inductance of the slotless machine introduces a controls challenge, but it can be overcome with today's enabling technology of wide bandgap devices. A comprehensive analysis and comparison of the slotless design with an equivalent slotted-radial version showed the superiority of the former. An optimum slotless design has been prototyped and test results along with analysis are presented.}, number={6}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Islam, Md Sariful and Mikail, Rajib and Husain, Iqbal}, year={2019}, pages={5789–5799} }