@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{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_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_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} }
 @article{mikail_husain_sozer_islam_sebastian_2014, title={A Fixed Switching Frequency Predictive Current Control Method for Switched Reluctance Machines}, volume={50}, ISSN={["1939-9367"]}, DOI={10.1109/tia.2014.2322144}, abstractNote={The paper presents a novel fixed switching frequency predictive current control method for switched reluctance machines (SRM). The proposed deadbeat predictive current controller accurately predicts the required duty ratio for the PWM pulse for a given reference current in each digital time step over the entire speed range of operation. The pulse width depends on the operating conditions, machine parameters and the rotor position. The controller utilizes the machine inductance profile as a function of current and rotor position to accurately predict the required voltage. The control method is studied through computer simulation and followed by experimental validation. The method is suitable for torque ripple sensitive applications requiring accurate tracking of a given current profile and mitigating the audible noise due to the switching of the inverter.}, number={6}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Mikail, Rajib and Husain, Iqbal and Sozer, Yilmaz and Islam, Mohammad S. and Sebastian, Tomy}, year={2014}, pages={3717–3726} }
 @inproceedings{mikail_husain_islam_2013, title={Finite element based analytical model for controller development of switched reluctance machines}, DOI={10.1109/ecce.2013.6646801}, abstractNote={This paper presents a novel method of modeling SRM including mutual coupling effect based on Finite Element Analysis (FEA). Once the machine geometry and design is completed in FEA, it is required to analyze the performance of the machine at different operating conditions with different control methods. Designing control algorithm with FEA in the loop is not convenient because of the complexity and simulation time involved. An analytical model performing similar to the FEA model and including the mutual coupling effect is desired variable speeds of operation. The self and mutual λ-i-θ during tuning of the control algorithm at different modes and characteristics of the machine can be derived from the FEA on the λ-i-θ characteristics of the machine is developed which can model and stored in a look-up table. A state space model based be readily coupled to any controller model. The method incorporates the mutual coupling effect which cannot be neglected for accurate modeling and good controller performance.}, booktitle={2013 ieee energy conversion congress and exposition (ecce)}, author={Mikail, R. and Husain, I. and Islam, M.}, year={2013}, pages={920–925} }
 @article{mikail_husain_sozer_islam_sebastian_2013, title={Torque-Ripple Minimization of Switched Reluctance Machines Through Current Profiling}, volume={49}, ISSN={["0093-9994"]}, DOI={10.1109/tia.2013.2252592}, abstractNote={This paper presents a novel method of profiling the phase currents to minimize the torque ripple of a switched reluctance machine. The method is a combination of machine design and control algorithm. The minimization is accomplished in three steps: The first step is to design a machine that has symmetric torque characteristics with an extended flat portion, the second step is to find the required current profile through simulation, and the third step is the fine tuning of the profile. The simulation is done to verify the method through a coupling of the finite-element-based machine model and the Matlab/Simulink-based dynamic controller model. The coupled simulation considers the nonlinearities, electrical loss, magnetic loss, and mutual coupling. Experimental verification validated the torque-ripple minimization procedure.}, number={3}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Mikail, Rajib and Husain, Iqbal and Sozer, Yilmaz and Islam, Mohammad S. and Sebastian, Tomy}, year={2013}, pages={1258–1267} }
 @inproceedings{mikail_husain_sozer_islam_sebastian_2012, title={A fixed switching frequency predictive current control method for switched reluctance machines}, DOI={10.1109/ecce.2012.6342731}, abstractNote={The paper presents a novel fixed switching frequency predictive current control method for switched reluctance machines (SRM). The proposed deadbeat predictive current controller accurately predicts the required amount of on-time for the PWM pulse for a given reference current in each digital time step over the entire speed range of operation. The required pulse width depends on the operating conditions, machine parameters and the rotor position. The controller utilizes the machine inductance profile as a function of current and rotor position to accurately predict the required voltage. The control method is studied through computer simulation and followed by experimental validation. The method is suitable for torque ripple sensitive applications requiring accurate tracking of a given current profile and mitigating the audible noise due to the switching of the inverter.}, booktitle={2012 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Mikail, R. and Husain, I. and Sozer, Y. and Islam, M. and Sebastian, T.}, year={2012}, pages={843–847} }
 @inproceedings{mikail_husain_sozer_islam_sebastian_2012, title={Four-quadrant torque ripple minimization of switched reluctance machine through current profiling with mitigation of rotor eccentricity problem and sensor errors}, DOI={10.1109/ecce.2012.6342732}, abstractNote={The paper presents a method of profiling the phase currents to minimize the torque ripple of switched reluctance machines (SRM) operating in four quadrant mode over the entire speed range of operation. A single quadrant current profiling presented in [1] is extended to be applicable in the four quadrant mode of operation. The method is based on machine and controller design through coupled simulation of the finite element based machine model and the dynamic controller model. The coupled simulation considers the magnetic nonlinearities, electrical and magnetic losses, and mutual coupling. The research quantifies the effect of position sensor error and manufacturing build variations on the level of torque ripple minimization. The mitigation processes to account for those issues in mass production are also presented.}, booktitle={2012 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Mikail, R. and Husain, I. and Sozer, Y. and Islam, M. and Sebastian, T.}, year={2012}, pages={838–842} }