@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_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{chattopadhyay_islam_mikailz_husain_2021, title={Partial Discharge Analysis and Insulation Design of High Speed Slotless Machine for Aerospace Applications}, ISSN={["2329-3721"]}, DOI={10.1109/ECCE47101.2021.9595949}, abstractNote={Slotless motor is a suitable propulsion component candidate for high speed aerospace applications due to their light Rotor Support weight, low iron losses and superior efficiency at higher speeds (high frequency) of operation. However, insulation design for Halbach Array the winding, non-magnetic teeth and the surrounding regions Stator Windings for a slotless machine require added attention during the design process due to the low pressure and high altitudes associated with aerospace applications. This paper presents the analysis and Winding Support insulation design of a slotless motor with random wound magnet Stator Lamination wire conductors for a low pressure environment. The effect of potting thickness, air bubbles in the potting, relative permittivity of insulation, and slew rate on insulation design is analyzed using finite element methods.}, journal={2021 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE)}, author={Chattopadhyay, Ritvik and Islam, Md Sariful and Mikailz, Rajib and Husain, Iqbal}, year={2021}, pages={4075–4080} }
 @inproceedings{chattopadhyay_gohil_acharya_nair_bhattacharya_2018, title={Efficiency improvement of three port high frequency transformer isolated triple active bridge converter}, volume={2018-March}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85046944973&partnerID=MN8TOARS}, DOI={10.1109/apec.2018.8341262}, abstractNote={This paper discusses and compares few techniques for efficiency improvement of Three-port Triple Active Bridge(TAB) Converter. Transformer isolated three port phase shifted Triple Active Bridge dc-dc converters are very efficient in nature providing high efficiency, ZVS operation over wide range, galvanic isolation and bidirectional power flow capability. The natural turn-on ZVS for switching devices in DAB or TAB converters is a very useful property for using Mosfets, as it reduces the device losses by a huge margin. The natural ZVS is lost for phase shifted converters at low power operating regions, causing reduction in efficiency. This paper discusses a comparsion between phase shift operation at fixed frequency vs phase shift operation at varying frequency and varying duty cycle operation at fixed frequency, which leads to a greater operating range of natural turn-on ZVS thus improving the efficiency. A comparison of the three methods have been presented in this paper with experimental results from a 10kW hardware prototype made of SiC Mosfets.}, booktitle={Thirty-third annual ieee applied power electronics conference and exposition (apec 2018)}, author={Chattopadhyay, R. and Gohil, G. and Acharya, Sayan and Nair, V. and Bhattacharya, S.}, year={2018}, pages={1807–1814} }
 @inproceedings{chattopadhyay_raheja_gohil_nair_bhattacharya_2018, title={Sensorless phase shift control for phase shifted DC-DC converters for eliminating DC transients from transformer winding currents}, volume={2018-March}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85046958041&partnerID=MN8TOARS}, DOI={10.1109/apec.2018.8341274}, abstractNote={The paper presents a two phase shift control strategy for Dual Active Bridge(DAB) and Triple Active Bridge(TAB) converter to eliminate the dc transients from the high frequency transformer winding currents during operating phase angle change from one cycle to the next cycle. The proposed two phase shift method controls the alternating nature of high frequency current in transformer windings in one switching cycle without using any high frequency current sensor. The proposed control strategy applies two different phase shift angles during positive and negative half cycles in order to eliminate the dc transients from transformer winding currents during steady state phase angle change. The control strategy is analyzed and applied for power flow direction reversal of Dual Active Bridge Converter and for changing power flow mode from three port scenario to two port scenario in case of Triple Active Bridge converter. The proposed control strategy study has been verified by performing experimental study on a hardware prototype.}, booktitle={Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC}, author={Chattopadhyay, R. and Raheja, U. and Gohil, G. and Nair, V. and Bhattacharya, Subhashish}, year={2018}, pages={1882–1889} }
 @article{khan_norris_chattopadhyay_husain_bhattacharya_2017, title={Autoinspection and Permitting With a PV Utility Interface (PUI) for Residential Plug-and-Play Solar Photovoltaic Unit}, volume={53}, ISSN={["1939-9367"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85018514651&partnerID=MN8TOARS}, DOI={10.1109/tia.2016.2631135}, abstractNote={Renewable energy resources are becoming popular with mass adoption in residential and commercial applications because of gradual cost reduction along with continuous technical advancements. Photovoltaic (PV) energy is one of the biggest players of renewable energy installations although soft costs remain as the major barrier for higher penetration of PV systems. To address the cost challenges, a plug-and-play (PnP) system for a quick, low-cost installation is proposed and designed. The method is much less invasive and labor intensive than the traditional installation methods. This paper presents the PnP electrical system, with emphasis on the controls, software, and system-level communications within the system. A PV utility interface circuit has been developed for automated electrical safety checks and authentication for the PnP PV system. A data protocol has been used to deal with the master–slave controller setup in the system. This research has the potential to reduce the residential PV system price by $0.6/W.}, number={2}, journal={IEEE TRANSACTIONS ON INDUSTRY APPLICATIONS}, author={Khan, Md Tanvir Arafat and Norris, Gregory and Chattopadhyay, Ritwik and Husain, Iqbal and Bhattacharya, Subhashish}, year={2017}, pages={1337–1346} }
 @inproceedings{chattopadhyay_acharya_gohil_bhattacharya_2017, title={One switching cycle current control strategy for triple active bridge phase-shifted DC-DC converter}, volume={2017-January}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85044242331&partnerID=MN8TOARS}, DOI={10.1109/ias.2017.8101785}, abstractNote={The paper presents two types of one cycle current control method for Triple Active Bridge(TAB) phase-shifted DC-DC converter integrating Renewable Energy Source(RES), Energy Storage System(ESS) and a output dc bus. The main objective of the current control methods is to control the transformer current in each cycle so that dc transients are eliminated during phase angle change from one cycle to the next cycle. In the proposed current control methods, the transformer currents are sampled within a switching cycle and the phase shift angles for the next switching cycle are generated based on sampled current values and current references. The discussed one cycle control methods also provide an inherent power decoupling feature for the three port phase shifted triple active bridge converter. Two different methods, (a) sampling and updating twice in a switching cycle and (b) sampling and updating once in a switching cycle, are explained in this paper. The current control methods are experimentally verified using digital implementation technique on a laboratory made hardware prototype.}, booktitle={2017 ieee industry applications society annual meeting}, author={Chattopadhyay, R. and Acharya, Sayan and Gohil, G. and Bhattacharya, S.}, year={2017}, pages={1–8} }
 @inproceedings{chattopadhyay_juds_gohil_gulur_ohodnicki_bhattacharya_2017, title={Optimized design for three port transformer considering leakage inductance and parasitic capacitance}, volume={2017-January}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85041441738&partnerID=MN8TOARS}, DOI={10.1109/ecce.2017.8096588}, abstractNote={The power flow capability of high frequency phase-shifted dc-dc converter depends on transformer leakage inductance and switching frequency. The design of multi-port transformer requires optimized volume and losses with required leakage inductance for rated power flow. Use of fast-switching SiC devices also demand low inter-winding parasitic capacitance for reduced common mode current. The work in this paper focuses on loss-volume optimized design of three port high frequency transformer integrating PV and Energy Storage(ES) based on leakage inductance and parasitic capacitance model. Two laboratory prototypes of 50kHz and 100kHz operating frequency have been designed to verify the leakage and parasitic capacitance model based design and the losses of the transformers.}, booktitle={2017 IEEE Energy Conversion Congress and Exposition, ECCE 2017}, author={Chattopadhyay, R. and Juds, M.A. and Gohil, G. and Gulur, S. and Ohodnicki, P.R. and Bhattacharya, Subhashish}, year={2017}, pages={3247–3254} }
 @inproceedings{chattopadhyay_gohil_bhattacharya_2017, title={Split-winding type three limb core structured HF transformer for integrating PV and energy storage(ES)}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85020040493&partnerID=MN8TOARS}, DOI={10.1109/apec.2017.7931123}, abstractNote={The work presented in this paper focuses on the drawbacks of three limb three winding transformer for use in three port dc-dc converter and proposes a split-winding type transformer approach using three limb core for use in three port dc-dc converter. The three limb three winding type transformer has drawback due to limitation of power flow when one port is idle and also has a very limited ZVS operating region for phase shift control. The proposed split-winding type transformer has the equivalent circuit of single core based transformer, has no limitation of power flow when one of the three port is idle and has wide ZVS range. Detailed analysis for idle condition operation, equivalent circuit derivation and ZVS operating range analysis is carried out in this paper.}, booktitle={Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC}, author={Chattopadhyay, R. and Gohil, G. and Bhattacharya, Subhashish}, year={2017}, pages={2997–3004} }
 @inproceedings{chattopadhyay_bhattacharya_2016, title={Decoupled power flow using phase shift control and ZVS cases for a three limb high frequency transformer based three-port DAB integrating PV and energy storage}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85002213818&partnerID=MN8TOARS}, DOI={10.1109/ias.2016.7731872}, abstractNote={The work presented in this paper focuses on the decoupled power flow control using phase shift control technique and resulting ZVS scenarios for three-limb high frequency transformer enabled three port Dual Active Bridge(DAB) converter, integrating PV and Energy Storage(ES). The advantage of using three-limb transformer is the low inter-winding parasitic capacitances due to positioning of windings on different limbs and elimination of high insulation requirements unlike concentric windings. The focus of the paper is based on decoupled power flow control of three port DAB using phase shift control, and ZVS scenario study under the phase shift control. Detailed analysis for power flow control and turn-on/turn-off ZVS conditions have been realized. Detailed Simulation Studies have been done and comprehensive results have been obtained for 700V dc PV//ES voltage and 1200V dc output voltage.}, booktitle={IEEE Industry Application Society, 52nd Annual Meeting: IAS 2016}, author={Chattopadhyay, R. and Bhattacharya, Subhashish}, year={2016} }
 @inproceedings{tripathi_madhusoodhanan_mainali_vcchalapu_chattopadhyay_bhattacharya_2016, title={Enabling DC microgrids with direct MV DC interfacing DAB converter based on 15 kV SiC IGBT and 15 kV SiC MOSFET}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85015358617&partnerID=MN8TOARS}, DOI={10.1109/ecce.2016.7855078}, abstractNote={The 15 kV SiC IGBT and 15 kV SiC MOSFET have been recently developed to enable non-cascaded high-frequency (HF) MV converters. Such direct MV DC interfacing Dual Active Bridge (DAB) converter is getting popular for DC micro-grid application due to higher efficiency, higher power-density and higher MTBF over the cascaded DAB topology. The high dv/dt in these devices on hard-switching with their inherent parasitics, causes increased EMI and switching loss. The suitability of the two family of SiC devices for an application, depends on the switching frequency, load range and magnitude of power, operating temperature and converter power density. This paper compares the two devices for a MV DAB application for dc micro-grid based on simulation and also with supporting MV side converter experiments up to 10kV DC bus and under 5–20kHz switching frequencies.}, booktitle={ECCE 2016 - IEEE Energy Conversion Congress and Exposition, Proceedings}, author={Tripathi, A. and Madhusoodhanan, S. and Mainali, K. and Vcchalapu, K. and Chattopadhyay, R. and Bhattacharya, Subhashish}, year={2016} }
 @inproceedings{chattopadhyay_juds_ohodnicki_bhattacharya_2016, title={Modelling, design and analysis of three limb high frequency transformer including transformer parasitics, for SiC Mosfet based three port DAB}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85010028398&partnerID=MN8TOARS}, DOI={10.1109/iecon.2016.7793593}, abstractNote={The work presented in this paper focuses on the transformer modelling, design and parasitic capacitances' effect on transformer operation for three-limb high frequency transformers designed for three port Dual Active Bridge(DAB) converter, using 1200V and 1700V SiC devices. The effects of parasitic capacitance due to high speed and high frequency switching enabled by SiC Mosfet devices are investigated in this paper for three limb transformer of DAB converter. The focus of the paper is based on design, estimation and measurement of parasitic capacitance and leakage inductance for three limb high frequency transformer. Detailed transformer model analysis has been realized for three port DAB operation with parasitics included. Two different transformer design approaches for 10kW, 50kHz rating have been carried out and comparative results have been analyzed in this paper.}, booktitle={IECON Proceedings (Industrial Electronics Conference)}, author={Chattopadhyay, R. and Juds, M.A. and Ohodnicki, P.R. and Bhattacharya, Subhashish}, year={2016}, pages={4181–4186} }
 @inproceedings{chattopadhyay_bhattacharya_2016, title={Power flow control and ZVS analysis of three limb high frequency transformer based three-port DAB}, volume={2016-May}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84973597860&partnerID=MN8TOARS}, DOI={10.1109/apec.2016.7467960}, abstractNote={The work presented in this paper focuses on the power flow control and study of three-limb high frequency transformer enabled three port Dual Active Bridge(DAB) converter, using 1200V and 1700V SiC devices. The advantage of using three-limb transformer is given by the low inter-winding parasitic capacitances due to placement of windings on different limbs and elimination of inter-winding insulations unlike concentric windings. The focus of the paper is based on power characterization for independent power flow of three port DAB using modulation control, and ZVS scenario study under the modulation control. Detailed analysis for power flow control and turn-on/turn-off ZVS conditions have been realized. A laboratory scale prototype using SiC Mosfets has been made and experimental results have been obtained for 500V dc input voltages and 1000V dc output voltage at 8.2kW of power.}, booktitle={Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC}, author={Chattopadhyay, R. and Bhattacharya, Subhashish}, year={2016}, pages={778–785} }
 @inproceedings{chattopadhyay_bhattacharya_2016, title={ZVS analysis and power flow control for three limb transformer enabled SiC Mosfet based three port DAB integrating PV and Energy Storage(ES)}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85015404568&partnerID=MN8TOARS}, DOI={10.1109/ecce.2016.7855565}, abstractNote={Multi-port dc-dc converters are the modular power electronic building blocks for integration of PV and Energy Storages(ES). The work in this paper focuses on ZVS characteristics for independent power flow control of three port DAB converter integrating PV and Energy Storage(ES), using three limb high frequency transformer. The independent power flow control discussed here, focuses on ES charging scenario for the converter using two different modulation techniques. ZVS scenario variations for two different modulation control technique for two different designs of three limb transformers, are discussed in the paper. A laboratory scale prototype using 1200V and 1700V SiC Mosfets has been made and preliminary results have been obtained for experimental validation of the ZVS scenarios.}, booktitle={ECCE 2016 - IEEE Energy Conversion Congress and Exposition, Proceedings}, author={Chattopadhyay, R. and Bhattacharya, Subhashish}, year={2016} }
 @inproceedings{khan_norris_chattopadhyay_husain_bhattacharya_2015, title={Auto-inspection and permitting with a PV Utility Interface (PUI) for residential plug-and-play solar photovoltaic unit}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84963549051&partnerID=MN8TOARS}, DOI={10.1109/ecce.2015.7310469}, abstractNote={Renewable energy resources are becoming popular with mass adoption in residential and commercial applications because of gradual cost reduction along with continuous technical advancements. Photovoltaic (PV) energy is one of the biggest players of renewable energy installations although soft costs remain as a major barrier for higher penetration of PV systems. To significantly lower the soft costs related to residential photovoltaic system installations, a Plug-and-Play (PnP) system has been designed which allows for a quick, low-cost installation. The method is much less invasive and labor intensive than traditional installation methods involving drilling holes through walls and installing additional panel boxes within the house. This paper presents the PnP electrical system, with emphasis on the controls, software, and system level communications within the system. A PV Utility Interface (PUI) circuit has been developed for automated electrical safety checks and authentication for implementing the PnP PV system. A data protocol has been used to deal with the master-slave controller setup in the system.}, booktitle={2015 IEEE Energy Conversion Congress and Exposition, ECCE 2015}, author={Khan, M.T.A. and Norris, G. and Chattopadhyay, R. and Husain, I. and Bhattacharya, Subhashish}, year={2015}, pages={5763–5770} }
 @inproceedings{azidehak_chattopadhyay_acharya_tripathi_kashani_chavan_bhattacharya_2015, title={Control of modular dual active bridge DC/DC converter for photovoltaic integration}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84963537568&partnerID=MN8TOARS}, DOI={10.1109/ecce.2015.7310140}, abstractNote={The DC transmission system provides a cost effective solution for long distance power transmission compared to the AC transmission system. Hence, this has increased the emphasis on the development of the DC transmission system. Development of power converter with modular structure has now made it possible to achieve higher voltage and power level. This opens the possibility for further development of a multi-terminal DC grid. Now once the DC grid system has been formed, it is also important to include more renewable energy sources directly to the DC grid. Therefore, a power conversion stage is required to condition the available power from a source to the grid. This paper shows the operation and control of such a kind of converter system which integrates the solar cell to the DC grid directly. The paper mainly focuses on control of the series connected DAB that have been integrated to HVDC power network. In order to deliver power in HVDC system, the total number of DABs must be high enough to achieve the DC link voltage. The control in that case must be a combination of current and voltage control. In order to validate the proposed control, complete system has been implemented on Opal-RT™ and hardware in the loop (HIL) using external controller has also been implemented to show the system operation.}, booktitle={2015 ieee energy conversion congress and exposition (ecce)}, author={Azidehak, A. and Chattopadhyay, R. and Acharya, Sayan and Tripathi, A. K. and Kashani, M. G. and Chavan, G. and Bhattacharya, S.}, year={2015}, pages={3400–3406} }
 @inproceedings{chattopadhyay_bhattacharya_2015, title={Modular isolated DC-DC converter with multi-limb transformer for interfacing of renewable energy sources}, volume={2015-May}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84937960339&partnerID=MN8TOARS}, DOI={10.1109/apec.2015.7104785}, abstractNote={This paper presents a modular isolated scalable three phase dual active bridge(DAB) DC-DC converter configuration using three multi limb high frequency transformers. The proposed converter has the advantage of having multiple low and high voltage dc links, which can be used at different power levels. The converter has three high voltage dc links which can be used for cascaded inverters or can be connected in series to provide a high dc link voltage for medium voltage grid-tie inverter. Multiple number of renewable energy sources(RES) can be connected to the low voltage side dc links to feed power to the grid. The paper work contains converter configuration, equivalent circuit of multi limb transformer, control of converter for a single renewable energy source and multiple renewable energy sources.}, number={May}, booktitle={Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC}, author={Chattopadhyay, R. and Bhattacharya, Subhashish}, year={2015}, pages={3039–3046} }
 @inproceedings{patel_chattopadhyay_madhusoodhanan_bhattacharya_sawant_chandorkar_2014, title={Flux vector modulation for single-phase inverter with LC output filter}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84900463911&partnerID=MN8TOARS}, DOI={10.1109/apec.2014.6803510}, abstractNote={The inverter often connects to load or grid through inductor-capacitor (LC) filter for feeding the filtered voltage and current. The carrier based modulation techniques, such as sinusoidal pulse width modulation (SPWM) and space vector modulation (SVM), require some kind of current control in LC filter connected inverter to damp out the LC resonance. The major advantage of flux vector modulation for the inverter with output LC filter is that the voltage control loop alone can damp out the resonance of LC filter. Hence, there is no need to use extra passive components or active damping controller. In this paper, the flux vector modulation for single-phase voltage source inverter (VSI) is proposed. The theoretical development and the digital implementation steps of flux vector modulation are described. The synchronously rotating reference frame (SRRF) proportional-integral (PI) controller is used for output voltage control for stand-alone operation of inverter. The single-phase inverter with output LC filter in stand-alone mode controlled by only voltage control loop with the flux vector modulation is validated through laboratory experiments.}, booktitle={Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC}, author={Patel, D.C. and Chattopadhyay, R. and Madhusoodhanan, S. and Bhattacharya, Subhashish and Sawant, R.R. and Chandorkar, M.C.}, year={2014}, pages={1530–1536} }
 @inproceedings{chattopadhyay_bhattacharya_foureaux_silva_cardoso_paula_pires_cortizio_moraes_brito_2014, title={Low voltage PV power integration into medium voltage grid using high voltage SiC devices}, booktitle={2014 international power electronics conference (ipec-hiroshima 2014 - ecce-asia)}, author={Chattopadhyay, R. and Bhattacharya, S. and Foureaux, N. C. and Silva, S. M. and Cardoso, F. B. and Paula, H. and Pires, I. A. and Cortizio, P. C. and Moraes, L. and Brito, J. A. D.}, year={2014}, pages={3225–3232} }