@article{kim_lee_bhattacharya_2022, title={Improved EEMF-Based Position Sensorless Control for Non-sinusoidal Back-EMF PMSMs}, volume={1}, ISSN={["2093-7423"]}, DOI={10.1007/s42835-021-00985-1}, journal={JOURNAL OF ELECTRICAL ENGINEERING & TECHNOLOGY}, author={Kim, Heonyoung and Lee, Kibok and Bhattacharya, Subhashish}, year={2022}, month={Jan} }
 @article{kim_anurag_acharya_bhattacharya_2021, title={Analytical Study of SiC MOSFET Based Inverter Output dv/dt Mitigation and Loss Comparison With a Passive dv/dt Filter for High Frequency Motor Drive Applications}, volume={9}, ISSN={["2169-3536"]}, url={https://doi.org/10.1109/ACCESS.2021.3053198}, DOI={10.1109/ACCESS.2021.3053198}, abstractNote={Fast switching characteristic of wide bandgap devices enables high switching frequency of power devices and thereby, can facilitate high fundamental frequency operation of electrical machines. However, with the switching transition times in orders of tens of nanoseconds, the high dv/dt is observed across the switching device. The high dv/dt experienced by the switches, and consequently by the machine, can degrade winding insulations or bearings over a period of time. Therefore, it is imperative to maintain the dv/dt below recommended values depending on the machine insulation. The dv/dt across the devices can be adjusted by varying the gate resistance. A high value of gate resistance, however, introduces additional switching losses on the device. Using different dv/dt filtering techniques can also help to control the dv/dt on the machine terminals. These techniques do not increase the switching losses on the device. However, it introduces additional losses in the filter resistors and also increases the cost of the system. In this paper, an analysis based on the impact of gate resistance on the dv/dt across the machine, and the corresponding losses is carried out. An analytical dv/dt filter design strategy is proposed to limit the dv/dt to a particular value. With the proposed design scheme, the value of each filter component can be easily obtained, and filter losses can be estimated accurately. Lastly, a comparison is performed on the basis of efficiency between these two techniques.}, journal={IEEE ACCESS}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Kim, Heonyoung and Anurag, Anup and Acharya, Sayan and Bhattacharya, Subhashish}, year={2021}, pages={15228–15238} }
 @article{simizu_byerly_schneider_kim_nations_narasimhan_beddingfield_bhattachayara_mchenry_2021, title={Flux Switching Permanent Magnet Motor with Metal Amorphous Nanocomposite Soft Magnetic Material and Rare Earth Free Permanent Magnets}, ISSN={["2329-3721"]}, DOI={10.1109/ECCE47101.2021.9594971}, abstractNote={The power losses in high power-density motors due to high rotational speed and/or high pole counts may be reduced adopting metal amorphous nanocomposites (MANCs) featuring low power loss and a relatively high flux density ($\sim$1.3 T). We recently proposed a flux switching permanent magnet (FSPM) motor with a rating of 2.5 kW at 1400 Hz electrical speed that incorporates low loss (<3W/kg at 1 kHz) FeNi-based MANC with projected iron loss of about 5 W. The motor design allows use of rare earth-free permanent magnets. To incorporate MANCs, an axial flux motor with rotor and stator cores made from a wound ribbon has been developed. We performed 3-d FEA to optimize the design and built and tested a prototype showing that low loss MANC material can be used for motor applications with high magnetic switching frequency.}, journal={2021 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE)}, author={Simizu, Satoru and Byerly, Kevin and Schneider, Kyle and Kim, Heonyoung and Nations, Mark and Narasimhan, Sneha and Beddingfield, Richard and Bhattachayara, Subhashish and McHenry, Michael E.}, year={2021}, pages={3866–3872} }
 @article{lee_shin_park_kim_kim_2021, title={Reliable Flux-Based Detection of Induction Motor Rotor Faults From the Fifth Rotor Rotational Frequency Sideband}, volume={68}, ISSN={["1557-9948"]}, DOI={10.1109/TIE.2020.3016241}, abstractNote={Motor current signature analysis (MCSA) is widespread in the field as a means of providing remote, online monitoring of industrial induction motor rotor faults. However, numerous cases of false indications with MCSA produced due to asymmetries in the rotor structure or load leading to unnecessary inspection or forced outages have been reported. Although alternative test methods under motor standstill or starting transient immune to the false indications have been proposed, a reliable method capable of “online” monitoring is desirable. In this article, a new fault indicator in the airgap or stray flux capable of reliable online detection is proposed. It is shown that the fifth sideband of the rotor rotational speed frequency can provide detection of rotor faults immune to most of the false MCSA indications. Experimental results under the most common false indications are provided to verify the claims made for cases where online MCSA produces false indications. The proposed fault indicator is also shown to be immune to eccentricity and common load defects such as load unbalance and misalignment.}, number={9}, journal={IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS}, author={Lee, Sang Bin and Shin, Jaehoon and Park, Yonghyun and Kim, Heonyoung and Kim, Jongwan}, year={2021}, month={Sep}, pages={7874–7883} }
 @article{lee_kim_lukic_2020, title={A Rotating Restart Method for Scalar (v/f) Controlled Synchronous Reluctance Machine Drives Using a Single DC-Link Current Sensor}, volume={8}, ISSN={["2169-3536"]}, DOI={10.1109/ACCESS.2020.3000220}, abstractNote={This paper presents a rotating restart method for $v/f$ scalar controlled Synchronous Reluctance Machines (SynRMs) using a single DC-link current sensor. In such a case, the initial rotor position and speed are required to restart the machine due to the absence of a position sensor. The method proposes to inject three active voltage vectors in the stationary reference frame to induce the phase currents required for estimating the rotor position and speed. In addition, the phase current reconstruction method is proposed to reduce the distortion of the measured phase currents caused by adopting a single DC-link current sensor and to consequently enhance the rotor position estimation accuracy. With the proposed method, the appropriate voltage vector can be applied to the machine, thus minimizing the inrush current during the restart. Furthermore, the proposed method only requires the machine parameters on the nameplate, and it does not require any additional machine-specific tuning processes. This paper proposes a simple restart method suitable for scalar-controlled SynRM drives with a single DC-link current sensor. The effectiveness of the proposed restart scheme is validated through the simulation and experimental results.}, journal={IEEE ACCESS}, author={Lee, Kibok and Kim, Heonyoung and Lukic, Srdjan M.}, year={2020}, pages={106629–106638} }
 @article{kim_han_lee_bhattacharya_2020, title={A Sinusoidal Current Control Strategy Based on Harmonic Voltage Injection for Harmonic Loss Reduction of PMSMs With Non-Sinusoidal Back-EMF}, volume={56}, ISSN={["1939-9367"]}, url={https://doi.org/10.1109/TIA.2020.3016210}, DOI={10.1109/TIA.2020.3016210}, abstractNote={In permanent magnet synchronous machine design, a limited number of stator and rotor slots distorts the air-gap flux distribution and its effective length. It causes machine parameters to vary with the rotor position. The rotor flux linkage harmonics introduce nonsinusoidal back-EMF, which causes current harmonics when conventional PI current controller is adopted. Those machines suffer from high-frequency torque ripple due to air-gap flux harmonics in low-speed region. However, in high-speed region, where the torque ripple is filtered out by the mechanical system, the torque ripple may be disregarded. In this case, torque-ripple suppression methods and the associated harmonic current components generate losses. Therefore, a sinusoidal current control is required to reduce the undesired harmonic losses. In this manner, this article focuses on the sinusoidal current control strategy based on harmonic voltage injection, which requires knowledge of rotor magnet flux linkage harmonics. This article also proposes both off- and on-line schemes for the identification of rotor magnet flux linkage harmonics. These methods do not require any proprietary machine design details such as the shape of stator or rotor for finite element analysis. Commonly used PI plus resonant controller is also designed and its disadvantages in terms of speed-dependent gain and stability, in comparison to the proposed scheme, are highlighted. Finally, experimental results are presented to compare the proposed scheme with the conventional method at different operating conditions.}, number={6}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Kim, Heonyoung and Han, Yongsu and Lee, Kibok and Bhattacharya, Subhashish}, year={2020}, month={Nov}, pages={7032–7043} }
 @article{kim_bhattacharya_2020, title={Improved Rotor Position Estimation in Extended Back-EMF Based Position Sensorless Control for IPMSMs with Non-Sinusoidal Back-EMF}, ISSN={["0197-2618"]}, DOI={10.1109/IAS44978.2020.9334884}, abstractNote={In terms of permanent magnet synchronous machine (PMSM) design, the limited number of stator and rotor slots distort the air-gap flux distribution and its effective length. It results in machine parameters varying with respect to the rotor position. The non-sinusoidal back-EMF, induced from the rotor flux linkage harmonics, introduces current harmonics when conventional d-q axis current controller is adopted. Consequently, it deteriorates the performance of the rotor position estimation in extended back-EMF based position sensorless control. It is because rotor position is estimated assuming sinusoidal machine current. Additionally, the harmonic currents introduces undesired losses which do not contribute to torque production. In this manner, a harmonic voltage injection based current control scheme is presented that results in sinusoidal machine current. It improves the performance of extended back-EMF based position sensorless control and mitigates the harmonic copper losses}, journal={2020 IEEE INDUSTRY APPLICATIONS SOCIETY ANNUAL MEETING}, author={Kim, Heonyoung and Bhattacharya, Subhashish}, year={2020} }
 @article{park_yang_kim_kim_lee_gyftakis_panagiotou_kia_capolino_2019, title={Stray Flux Monitoring for Reliable Detection of Rotor Faults Under the Influence of Rotor Axial Air Ducts}, volume={66}, ISSN={["1557-9948"]}, DOI={10.1109/TIE.2018.2880670}, abstractNote={Monitoring of induction motor faults based on stray flux measurement has been investigated by many researchers due to its potential benefits in cost and simplicity. Although it was shown that flux-based monitoring can provide sensitive fault detection comparable to that of motor current signature analysis, the lack of “remote” monitoring capability has limited its practical use. The performance and reliability of stray flux-based detection of induction motor rotor cage faults are evaluated in this paper. It is shown for the first time in this work that the spectrum analysis of the radial stray flux can provide reliable detection of rotor faults immune to the influence of rotor axial air ducts, which is the most common cause of false rotor fault alarms. The reliability and sensitivity of stray flux-based rotor fault detection are demonstrated through experimental testing on laboratory and 6.6 kV field motors.}, number={10}, journal={IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS}, author={Park, Yonghyun and Yang, Chanseung and Kim, Jongwan and Kim, Heonyoung and Lee, Sang Bin and Gyftakis, Konstantinos N. and Panagiotou, Panagiotis A. and Kia, Shahin Hedayati and Capolino, Gerard-Andre}, year={2019}, month={Oct}, pages={7561–7570} }
 @article{lee_hyun_kang_yang_shin_kim_park_kong_kim_2016, title={Identification of False Rotor Fault Indications Produced by Online MCSA for Medium-Voltage Induction Machines}, volume={52}, ISSN={["1939-9367"]}, DOI={10.1109/tia.2015.2464301}, abstractNote={Motor current signature analysis (MCSA) has become an essential part of the preventive maintenance program for monitoring the condition of the rotor cage in medium-voltage induction motors in the pulp and paper industry. However, many cases of false indications due to interference from the motor or the load have been reported. False indications can result in unnecessary inspection and outage costs (false positives) or major repair/replacement costs and loss of production (false negatives). The objective of this paper is to present the potential root causes of false indications and provide guidelines on how commercially available offline and online tests can be applied for identifying false indications from a field engineers' perspective. Case studies of false MCSA indications and results of alternative commercial tests for improving the reliability of the diagnosis are provided through measurements on 6.6-kV and laboratory motor samples. Finally, new test methods under research and development for reliable rotor fault detection are summarized, and unresolved problems are listed. This paper is expected to help field maintenance engineers prevent unnecessary motor inspection and forced outages and guide researchers target future research toward industrial needs.}, number={1}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Lee, Sang Bin and Hyun, Doosoo and Kang, Tae-june and Yang, Chanseung and Shin, Sungsik and Kim, Heonyoung and Park, Sungbong and Kong, Tae-Sik and Kim, Hee-Dong}, year={2016}, pages={729–739} }
 @article{kim_lee_park_kia_capolino_2016, title={Reliable Detection of Rotor Faults Under the Influence of Low-Frequency Load Torque Oscillations for Applications With Speed Reduction Couplings}, volume={52}, ISSN={["1939-9367"]}, DOI={10.1109/tia.2015.2508423}, abstractNote={Low-frequency torque oscillations in the load can induce frequency components in the vicinity of that of rotor faults (RFs) resulting in false alarms when applying motor current signature analysis (MCSA). False RF indications due to load oscillations (LO) are most common in applications that employ speed reduction couplings for high torque, low-speed operation. Recently, ideas for separating RF and LO have been proposed in the literature; however, the case where two components overlap at the same frequency has not been investigated. Several cases where RF- and LO-induced components are identical have been observed in the field by the authors with commercial MCSA equipment. It is shown in this paper that overlap between the two components can produce a false positive or false negative indication because they can add or cancel depending on the relative phase between the components. Alternative options for reliable RF testing among existing test methods are evaluated and verified in this paper for cases where the two components overlap and produce false indications.}, number={2}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Kim, Heonyoung and Lee, Sang Bin and Park, Sungbong and Kia, Shahin Hedayati and Capolino, Gerard-Andre}, year={2016}, pages={1460–1468} }