@inproceedings{uttam_iyer_2022, title={A Unified Modeling Approach for a Multi-Active Bridge Converter}, booktitle={2022 International Power Electronics Conference (IPEC-Himeji 2022-ECCE Asia)}, author={Uttam, Vishwabandhu and Iyer, Vishnu Mahadeva}, year={2022}, pages={1614–1620} }
 @article{vijayan_naik_raghunathan_iyer_2022, title={Contactless power transfer system and method for controlling the same}, note={US Patent 11,303,156}, author={Vijayan, Pradeep and Naik, Rajendra and Raghunathan, Arun Kumar and Iyer, Vishnu Mahadeva}, year={2022}, month={Apr} }
 @article{datta_iyer_osama_huh_rallabandi_2022, title={Electric power system for a vehicle}, note={US Patent 11,325,714}, author={Datta, Rajib and Iyer, Vishnu Mahadeva and Osama, Mohamed and Huh, Kum Kang and Rallabandi, Vandana Prabhakar}, year={2022}, month={May} }
 @inproceedings{sharma_iyer_bhattacharya_2021, title={A Load Profile Based Optimized Piecewise Droop Control for DC Microgrids}, booktitle={2021 IEEE Fourth International Conference on DC Microgrids (ICDCM)}, author={Sharma, Shrivatsal and Iyer, Vishnu Mahadeva and Bhattacharya, Subhashish}, year={2021}, pages={1–7} }
 @inproceedings{sharma_iyer_das_bhattacharya_2021, title={A Modified Droop Control Algorithm for DC Microgrids to Achieve Accurate Current Sharing and Improved Voltage Regulation}, booktitle={2021 IEEE Applied Power Electronics Conference and Exposition (APEC)}, author={Sharma, Shrivatsal and Iyer, Vishnu Mahadeva and Das, Partha Pratim and Bhattacharya, Subhashish}, year={2021}, pages={119–125} }
 @article{iyer_gulur_bhattacharya_kikuchi_sridharan_zou_chen_2021, title={An Active Voltage Stabilizer for a DC Microgrid System}, volume={9}, ISSN={["2169-3536"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85117593352&partnerID=MN8TOARS}, DOI={10.1109/ACCESS.2021.3087543}, abstractNote={This paper analyzes the low-frequency stability challenges that exist in a complex DC microgrid (MG) system. The converters that belong to a DC MG are categorized into different groups based on their control approach. The small-signal model of the DC MG is presented, and the conditions for system stability are derived. In some DC MG applications, there is the possibility of installing off-the-shelf converters with little flexibility and access for controller auto-tuning. To tackle this, a hardware-based active voltage stabilizer solution is proposed to stabilize the DC MG. The active stabilizer’s functionality, based on an isolated bidirectional DC-DC converter, is elucidated, and a suitable control strategy is proposed. The active stabilizer and its associated control configuration involve only local voltage sensing and are non-intrusive. A dual active bridge (DAB) converter-based active stabilizer is implemented, and hardware-based steady-state and transient experimental results from a DC MG test-bench are provided to validate the functionality and effectiveness of the proposed active stabilizer.}, journal={IEEE ACCESS}, publisher={IEEE}, author={Iyer, Vishnu Mahadeva and Gulur, Srinivas and Bhattacharya, Subhashish and Kikuchi, Jun and Sridharan, Srikanthan and Zou, Ke and Chen, Chingchi}, year={2021}, pages={86786–86800} }
 @inproceedings{prabowo_iyer_bhattacharya_aeloiza_2021, title={Controller Design for the Rating-Proportional Current Sharing in Modular Hybrid Critical Load Substation Transformers}, booktitle={2021 IEEE 12th Energy Conversion Congress & Exposition-Asia (ECCE-Asia)}, author={Prabowo, Yos and Iyer, Vishnu Mahadeva and Bhattacharya, Subhashish and Aeloiza, Eddy}, year={2021}, pages={899–905} }
 @article{vijayan_ramachandrapanicker_aravind_raghunathan_iyer_2021, title={System and method for charging receiver devices}, note={US Patent 10,897,153}, author={Vijayan, Pradeep and Ramachandrapanicker, Somakumar and Aravind, Deepak and Raghunathan, Arun Kumar and Iyer, Vishnu Mahadeva}, year={2021}, month={Jan} }
 @inproceedings{sharma_iyer_bhattacharya_kikuchi_zou_2021, title={Tertiary Control Method for Droop Controlled DC-DC converters in DC Microgrids}, booktitle={2021 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Sharma, Shrivatsal and Iyer, Vishnu Mahadeva and Bhattacharya, Subhashish and Kikuchi, Jun and Zou, Ke}, year={2021}, pages={694–699} }
 @article{gulur_iyer_bhattacharya_2020, title={A CM Filter Configuration for Grid-Tied Voltage Source Converters}, volume={67}, ISSN={["1557-9948"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85087450756&partnerID=MN8TOARS}, DOI={10.1109/TIE.2019.2949530}, abstractNote={Common mode (CM) filters play a crucial role in determining adherence to conducted emissions (CE) standards for grid-tied voltage source converters. Design and implementation of such filters can be challenging since they depend on several factors like identification of CM noise paths, fidelity of passive components and discerning the frequency and amplitude of CM noise sources. In this article, a CM filter has been proposed, which uses passive components along with the converter's heat sink as a circulating return path for the CM currents. Based on the presented CM circuit models with the proposed filter, a detailed design process has been delineated for selecting the passive components required to realize the CM filter. Additionally, the heat-sink potential has been shown to be touch safe during both ideal and nonideal grid conditions with the proposed CM filter. CE spectral results measured using a commercially procured line impedance stabilization network and captured time domain converter operational wave forms for a 2-level, 3$\phi$ grid-tied voltage source converter validate the functionality and effectiveness of the presented design.}, number={10}, journal={IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Gulur, Srinivas and Iyer, Vishnu Mahadeva and Bhattacharya, Subhashish}, year={2020}, pages={8100–8111} }
 @inproceedings{prabowo_iyer_bhattacharya_aeloiza_2020, title={A Control Method of Hybrid Transformer enabled Harmonic Isolator for Sensitive Clustered Harmonic Loads}, booktitle={2020 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Prabowo, Yos and Iyer, Vishnu Mahadeva and Bhattacharya, Subhashish and Aeloiza, Eddy}, year={2020}, pages={4872–4878} }
 @inproceedings{sharma_iyer_bhattacharya_kikuchi_zou_gupta_2020, title={A Methodology for Seamless Hot-Swap of Converters in DC Microgrids}, booktitle={IECON 2020 The 46th Annual Conference of the IEEE Industrial Electronics Society}, author={Sharma, Shrivatsal and Iyer, Vishnu Mahadeva and Bhattacharya, Subhashish and Kikuchi, Jun and Zou, Ke and Gupta, Mahima}, year={2020}, pages={3143–3150} }
 @inproceedings{iyer_sharma_bhattacharya_2020, title={A Methodology to Select the Number of Cascaded Cells for a Medium Voltage Multilevel AC-DC Solid State Transformer}, booktitle={2020 IEEE Transportation Electrification Conference & Expo (ITEC)}, author={Iyer, Vishnu Mahadeva and Sharma, Shrivatsal and Bhattacharya, Subhashish}, year={2020}, pages={55–61} }
 @inproceedings{iyer_gulur_bhattacharya_2020, title={An Active Damping Control Strategy for a Multi-Cell AC-DC Solid State Transformer}, booktitle={2020 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Iyer, Vishnu Mahadeva and Gulur, Srinivas and Bhattacharya, Subhashish}, year={2020}, pages={4842–4848} }
 @phdthesis{iyer_2020, title={An Approach Towards Extreme Fast Charging Station Architecture for Electric Vehicles with Partial Power Processing}, school={North Carolina State University}, author={Iyer, Vishnu Mahadeva}, year={2020} }
 @article{iyer_gulur_gohil_bhattacharya_2020, title={An Approach Towards Extreme Fast Charging Station Power Delivery for Electric Vehicles with Partial Power Processing}, volume={67}, ISSN={["1557-9948"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85086426816&partnerID=MN8TOARS}, DOI={10.1109/TIE.2019.2945264}, abstractNote={This article proposes an approach for realizing the power delivery scheme for an extreme fast charging (XFC) station that is meant to simultaneously charge multiple electric vehicles (EVs). A cascaded H-bridge converter is utilized to directly interface with the medium voltage grid while dual-active-bridge based soft-switched solid-state transformers are used to achieve galvanic isolation. The proposed approach eliminates redundant power conversion by making use of partial power rated dc–dc converters to charge the individual EVs. Partial power processing enables independent charging control over each EV, while processing only a fraction of the total battery charging power. Practical implementation schemes for the partial power charger unit are analyzed. A phase-shifted full-bridge converter-based charger is proposed. Design and control considerations for enabling multiple charging points are elucidated. Experimental results from a down-scaled laboratory test-bed are provided to validate the control aspects, functionality, and effectiveness of the proposed XFC station power delivery scheme. With a down-scaled partial power converter that is rated to handle only 27% of the battery power, an efficiency improvement of 0.6% at full-load and 1.6% at 50% load is demonstrated.}, number={10}, journal={IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS}, publisher={IEEE}, author={Iyer, Vishnu Mahadeva and Gulur, Srinivas and Gohil, Ghanshyamsinh and Bhattacharya, Subhashish}, year={2020}, pages={8076–8087} }
 @article{gulur_iyer_bhattacharya_2019, title={A Dual Loop Current Control Structure With Improved Disturbance Rejection For Grid Connected Converters}, volume={34}, ISSN={0885-8993}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85068727943&partnerID=MN8TOARS}, DOI={10.1109/TPEL.2019.2891686}, abstractNote={The increase in renewable energy penetration in the past few years has led to grave power quality issues in the utility grid. This has ushered in the need for a robust and stable control system for reference tracking and disturbance rejection with respect to grid connected converters. Typically, a simple proportional integrator (PI) controller is used in the synchronous reference frame (dq) for current control of grid connected systems. However, the PI controller in itself may be insufficient for disturbance rejection, when the utility grid voltages contain other harmonics in addition to the fundamental component. This paper introduces and analyzes a dual loop current control structure which utilizes two independent controllers, one for reference tracking and the other for disturbance rejection in the dq frame. A small signal model of the dual loop current control has been presented and its robustness under grid inductance variation, examined. Simulation and experimental results are presented to validate the dual loop strategy for improved disturbance rejection capability and filtering action during the presence of grid voltage harmonics and unbalances, without compromising on the reference tracking performance.}, number={10}, journal={IEEE Transactions on Power Electronics}, publisher={IEEE}, author={Gulur, S. and Iyer, V. Mahadeva and Bhattacharya, S.}, year={2019}, pages={1–1} }
 @inproceedings{iyer_gulur_bhattacharya_ramabhadran_2019, title={A partial power converter interface for battery energy storage integration with a DC microgrid}, booktitle={2019 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Iyer, Vishnu Mahadeva and Gulur, Srinivas and Bhattacharya, Subhashish and Ramabhadran, Ramanujam}, year={2019}, pages={5783–5790} }
 @inproceedings{agarwal_iyer_anurag_bhattacharya_2019, title={Adaptive Control of a Hybrid Energy Storage System for Wave Energy Conversion Application}, booktitle={2019 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Agarwal, Apoorv and Iyer, Vishnu Mahadeva and Anurag, Anup and Bhattacharya, Subhashish}, year={2019}, pages={4994–5001} }
 @inproceedings{iyer_gulur_bhattacharya_kikuchi_sridharan_zou_chen_2019, title={An active voltage stabilizer for a generic dc microgrid}, booktitle={2019 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Iyer, Vishnu Mahadeva and Gulur, Srinivas and Bhattacharya, Subhashish and Kikuchi, Jun and Sridharan, Srikanthan and Zou, Ke and Chen, Chingchi}, year={2019}, pages={462–468} }
 @inproceedings{prabowo_iyer_kim_bhattacharya_2019, title={Modeling and Stability Assessment of Single-Phase Droop Controlled Solid State Transformer}, booktitle={2019 10th International Conference on Power Electronics and ECCE Asia (ICPE 2019-ECCE Asia)}, author={Prabowo, Yos and Iyer, Vishnu Mahadeva and Kim, Byeongheon and Bhattacharya, Subhashish}, year={2019}, pages={3285–3291} }
 @article{agarwal_iyer_hazra_bhattacharya_2019, title={Optimal Integration of Hybrid Energy Storage System with Wave Energy Converter Systems and Analysis of Spatial WEC Array Arrangement}, author={Agarwal, Apoorv and Iyer, Vishnu Mahadeva and Hazra, Samir and Bhattacharya, Subhashish}, year={2019} }
 @article{iyer_gulur_bhattacharya_2019, title={Small-Signal Stability Assessment and Active Stabilization of a Bidirectional Battery Charger}, volume={55}, ISSN={0093-9994}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85053610599&partnerID=MN8TOARS}, DOI={10.1109/TIA.2018.2871101}, abstractNote={A two-stage electric vehicle (EV) battery charger typically consists of an ac–dc converter cascaded with a dc–dc converter. In such a cascaded system, maintaining stability at the intermediate dc link is imperative for reliable operation of the battery charger under different operating modes. This paper addresses the intermediate dc-link stability challenges that exist in a bidirectional two-stage grid connected single-phase battery charger. It is delineated that the small-signal load-dependent resistance of the ac–dc converter plays a crucial role in determining the stability of the bidirectional battery charger. A virtual-resistor-based active damping control strategy that does not require any additional sensors is explored for the ac–dc converter to stabilize the cascaded system under all operating modes irrespective of the power flow direction. Experimental results on a grid-connected single-phase battery charger hardware prototype are presented to validate the proposed models and showcase the improvement in the dc-link stability due to the virtual-resistance-based active damping approach.}, number={1}, journal={IEEE Transactions on Industry Applications}, publisher={IEEE}, author={Iyer, V. M. and Gulur, S. and Bhattacharya, S.}, year={2019}, month={Jan}, pages={563–574} }
 @article{vijayan_prabhakaran_collins_iyer_2019, title={System and method for fault ride through}, note={US Patent 10,476,264}, author={Vijayan, Pradeep and Prabhakaran, Satish and Collins, John Oliver and Iyer, Vishnu Mahadeva}, year={2019}, month={Nov} }
 @inproceedings{shah_iyer_bhattacharya_2018, title={An Approach to Unified Full-Order Modeling of Dual Active Bridge Type Converters}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85061537028&partnerID=MN8TOARS}, DOI={10.1109/IECON.2018.8591664}, abstractNote={Modeling of dual active bridge (DAB)type converters, and that of its single-phase form, is an active area of research. In this paper, a new modeling approach is proposed. It is theorised that single-phase DAB converter operating in any of its multiple modes and modulation may be modeled as four dual active half-bridge (DAHB)circuits operating in simple phase-shift modulation. It allows extension of the model developed for simple phase-shift modulated DAHB converter to any operating mode of the DAB converter. In this respect, the physical basis of the theory is first explained. Subsequently, the improved first harmonic approximation (I-FHA)model of the DAHB converter, developed a priori, is extended to the general operating case of the DAB converter. Finally, the model is validated through extensive simulation and hardware experiments proving the theoretical basis of the proposed approach.}, booktitle={IECON 2018 - 44th Annual Conference of the IEEE Industrial Electronics Society}, author={Shah, S. S. and Iyer, V. M. and Bhattacharya, S.}, year={2018}, month={Oct}, pages={986–992} }
 @book{vijayan_iyer_2018, title={DC converters with modified droop control and method of use}, url={https://patents.google.com/patent/US10097095B2/en}, number={US10097095B2}, author={Vijayan, P. and Iyer, V.M.}, year={2018}, month={Oct} }
 @article{vijayan_iyer_2018, title={DC converters with modified droop control and method of use}, note={US Patent 10,097,095}, author={Vijayan, Pradeep and Iyer, Vishnu Mahadeva}, year={2018}, month={Oct} }
 @book{vijayan_iyer_2018, title={Dc converters with modified droop control and method of use}, url={https://patents.google.com/patent/US20180083545A1/en}, number={US20180083545A1}, author={Vijayan, P. and Iyer, V.M.}, year={2018}, month={Mar} }
 @article{de_morgan_iyer_ke_zhao_vechalapu_bhattacharya_hopkins_2018, title={Design, Package, and Hardware Verification of a High-Voltage Current Switch}, volume={6}, ISSN={2168-6777}, url={http://dx.doi.org/10.1109/JESTPE.2017.2727051}, DOI={10.1109/JESTPE.2017.2727051}, abstractNote={In this paper, an attempt has been made to demonstrate various package design considerations to accommodate series connection of high voltage Si-IGBT (6500V/25A die) and SiC-Diode (6500V/25A die). The effects of connecting the cathode of the series diode to the collector of the IGBT versus connecting the emitter of the IGBT to the anode of the series diode have been analyzed in regards to parasitic line inductance of the structure. Various simulation results have then been used to redesign and justify the optimized package structure for the final current switch design. The package is fabricated using the optimized parameters. A double pulse test-circuit has been assembled. Initial hardware results have been shown to verify functioning. The main motivation of this work is to enumerate detailed design considerations for packing a high voltage current switch package.}, note={\urlhttps://ieeexplore.ieee.org/document/7981339/}, number={1}, journal={IEEE Journal of Emerging and Selected Topics in Power Electronics}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={De, A. and Morgan, A. J. and Iyer, V. Mahadeva and Ke, H. and Zhao, X. and Vechalapu, K. and Bhattacharya, S. and Hopkins, D. C.}, year={2018}, month={Mar}, pages={441–450} }
 @article{shah_iyer_bhattacharya_2018, title={Exact Solution of ZVS Boundaries and AC Currents in Dual Active Bridge Type DC-DC Converters}, volume={34}, ISSN={0885-8993}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85057892110&partnerID=MN8TOARS}, DOI={10.1109/TPEL.2018.2884294}, abstractNote={This letter presents an approach to develop an exact, unified model of zero voltage switching (ZVS) regions and ac-port currents (peak and RMS) in dual active bridge type dc–dc converters for all its operating modes and modulation strategies. It is executed for a single-phase system, where the method is used to compute closed-form expressions of ac current at switching instants. Then, exact formulae of ZVS regions for all devices, system peak, and RMS currents are derived. Simulation and hardware results for forward and reverse power transfer are reported to validate the proposed approach.}, number={6}, journal={IEEE Transactions on Power Electronics}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Shah, S. S. and Iyer, V. Mahadeva and Bhattacharya, S.}, year={2018}, pages={1–1} }
 @article{shah_iyer_bhattacharya_2018, title={Exact Solution of ZVS Boundaries and AC-Port Currents in Dual Active Bridge Type DC--DC Converters}, volume={34}, number={6}, journal={IEEE Transactions on Power Electronics}, publisher={IEEE}, author={Shah, Suyash Sushilkumar and Iyer, Vishnu Mahadeva and Bhattacharya, Subhashish}, year={2018}, pages={5043–5047} }
 @inproceedings{iyer_gulur_gohil_bhattacharya_2018, title={Extreme fast charging station architecture for electric vehicles with partial power processing}, volume={2018-March}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85046972946&partnerID=MN8TOARS}, DOI={10.1109/APEC.2018.8341082}, abstractNote={This paper introduces a power delivery architecture for an Extreme Fast Charging (XFC) station that is meant to simultaneously charge multiple electric vehicles (EVs) with a 300-mile range battery pack in about 15 minutes. The proposed approach can considerably improve overall system efficiency as it eliminates redundant power conversion by making use of partial power rated dc-dc converters to charge the individual EVs as opposed to a traditional fast charging station structure based on full rated dedicated charging converters. Partial power processing enables independent charging control over each EV, while processing only a fraction of the total battery charging power. Energy storage (ES) and renewable energy systems such as photovoltaic (PV) arrays can be easily incorporated in the versatile XFC station architecture to minimize the grid impacts due to multi-mega watt charging. A control strategy is discussed for the proposed XFC station. Experimental results from a scaled down laboratory prototype are provided to validate the functionality, feasibility and cost-effectiveness of the proposed XFC station power architecture.}, booktitle={2018 IEEE Applied Power Electronics Conference and Exposition (APEC)}, author={Iyer, V. M. and Gulur, S. and Gohil, G. and Bhattacharya, S.}, year={2018}, month={Mar}, pages={659–665} }
 @inproceedings{gulur_iyer_bhattacharya_2018, title={Improved Common Mode Noise Models for Three Level T-Type Neutral Point Clamped Converters}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85060285297&partnerID=MN8TOARS}, DOI={10.1109/ECCE.2018.8558405}, abstractNote={Three level $T$-type based converter (3LT2C) is becoming an attractive option in several grid connected power electronic applications as it offers several advantages like high efficiency, lower active component count compared to other three level converters and superior output ac voltage quality. Common mode (CM) based noise modeling for 3LT2C has not been thoroughly explored in literature. This work presents an improved CM noise model for a grid connected 3LT2C with an LCL filter. It is shown that the 3LT2C has two high frequency CM noise sources which are responsible for ground leakage current injection. The effect of both CM noise sources on the overall CM model has been examined under different switching frequencies using sine triangle pulse width modulation (SPWM). Along with detailed analysis, extensive simulation results have been provided to validate the presented CM noise model.}, booktitle={2018 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Gulur, S. and Iyer, V. M. and Bhattacharya, S.}, year={2018}, month={Sep}, pages={6398–6403} }
 @inproceedings{gulur_iyer_bhattacharya_2018, title={Proportional integral — Resonant and dual loop current control structure comparison for grid connected converters in the rotating frame}, volume={2018-March}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85046961004&partnerID=MN8TOARS}, DOI={10.1109/APEC.2018.8341233}, abstractNote={Over the past few years, due the increasing penetration of renewable energy, there has been a steady rise in the harmonic content in grid voltages. In such circumstances, a proportional integral (PI) based current control in the synchronous reference rotating frame (dq) for a grid connected voltage source converter may not be adequate to suppress the harmonic components and to precisely follow the fundamental frequency component with zero steady state error. Several current control structures have been proposed, with proportional integral — resonant controller (PI-RES) based structure being one of the most popular. In this paper, the PI-RES has been compared to the recently introduced dual loop current control structure. Both these current control structures have been compared in terms of their tracking, filtering and disturbance rejection capability. Robustness of both these structures has also been analyzed under a grid impedance variation. Simulation and experimental results have been provided to validate the analysis presented.}, booktitle={2018 IEEE Applied Power Electronics Conference and Exposition (APEC)}, author={Gulur, S. and Iyer, V. M. and Bhattacharya, S.}, year={2018}, month={Mar}, pages={1617–1623} }
 @inproceedings{wiemer_iyer_hinz_bhattacharya_doncker_2018, title={Small-Signal Modeling and Controller Design Considerations for Dyna-C AC-DC Converter}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85060316581&partnerID=MN8TOARS}, DOI={10.1109/ECCE.2018.8558281}, abstractNote={The Dyna-C ac-dc converter is a current-source-based topology featuring medium-frequency galvanic isolation. This paper presents the state-space based average and small signal modeling of Dyna-C ac-dc converter. A space vector based modulation strategy is developed, presented and validated by simulation. Based on the proposed small signal model for Dyna-C ac-dc converter, a two stage closed loop control approach is developed. The proposed approach comprises of an outer loop to regulate the transformer magnetizing-current and an inner $\boldsymbol{d}\boldsymbol{q}$-based vector control strategy for regulating the grid currents. Circuit simulation results are presented to validate the proposed models and the closed loop control scheme for the Dyna-C ac-dc converter.}, booktitle={2018 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Wiemer, A. and Iyer, V. M. and Hinz, A. and Bhattacharya, S. and Doncker, R. W. De}, year={2018}, month={Sep}, pages={1513–1520} }
 @inproceedings{gulur_iyer_bhattacharya_2018, title={Stationary reference frame based current control structure with improved disturbance rejection for grid connected converters}, volume={2018-March}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85046936440&partnerID=MN8TOARS}, DOI={10.1109/APEC.2018.8341142}, abstractNote={A proportional resonant (PR) controller is commonly used for tracking the reference current with zero steady state error in the stationary reference frame (abc or αβ) for the voltage source converter. Such a structure suffers from poor disturbance rejection capability when the grid voltages contain harmonic components. This results in higher harmonic distortion in the grid currents which is not desirable. This paper introduces a virtual loop based current control structure for improving the voltage and the current disturbance rejection capability. The virtual loop based current control structure also decouples the reference tracking and disturbance rejection leading to simpler controller designs. Frequency domain plots and analysis have been provided to validate the presented control structure. Detailed circuit simulation results have been used to verify the presented analysis.}, booktitle={2018 IEEE Applied Power Electronics Conference and Exposition (APEC)}, author={Gulur, S. and Iyer, V. M. and Bhattacharya, S.}, year={2018}, month={Mar}, pages={1031–1035} }
 @book{vijayan_ramachandrapanicker_aravind_raghunathan_iyer_2018, title={System and method for charging receiver devices}, url={https://patents.google.com/patent/US20180041066A1/en}, number={US20180041066A1}, author={Vijayan, P. and Ramachandrapanicker, S. and Aravind, D. and Raghunathan, A.K. and Iyer, V.M.}, year={2018}, month={Feb} }
 @article{vijayan_ramachandrapanicker_aravind_raghunathan_iyer_2018, title={System and method for charging receiver devices}, note={US Patent App. 15/667,444}, publisher={Google Patents}, author={Vijayan, Pradeep and Ramachandrapanicker, Somakumar and Aravind, Deepak and RAGHUNATHAN, Arun Kumar and IYER, Vishnu Mahadeva}, year={2018}, month={Feb} }
 @inproceedings{gulur_iyer_bhattacharya_2017, title={A dual loop current control structure with improved disturbance rejection for grid connected converters in the synchronous rotating reference frame}, volume={2017-January}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85041457092&partnerID=MN8TOARS}, DOI={10.1109/ecce.2017.8096684}, abstractNote={Increase in renewable energy penetration, in the recent past, has been one of the primary causes for serious issues in power quality of the utility grid. This has ushered in the need for a robust and stable control system for reference tracking and disturbance rejection of grid-connected converters. Conventionally, due to its simplicity and ability to achieve zero steady-state error, a simple proportional integral (PI) controller is used in the synchronous reference frame ($dq$) for current control of voltage-source based grid-connected systems. However, the PI controller by itself, may not suffice for adequate disturbance rejection, especially when the utility grid voltages contain other harmonics in addition to the fundamental component. This paper introduces and analyzes a dual-loop current control structure, which utilizes two independent controllers, one for reference tracking and the other for disturbance rejection in the $dq$ frame. A small signal model of the dual-loop current control has been presented and its robustness under grid impedance variation, examined. Extensive experimental results are presented to validate the dual-loop control strategy for improved disturbance rejection capability and filtering action during the presence of grid voltage disturbances and grid impedance variations, without compromising the reference tracking performance.}, booktitle={2017 ieee energy conversion congress and exposition (ecce)}, author={Gulur, S. and Iyer, V. M. and Bhattacharya, S.}, year={2017}, pages={3890–3896} }
 @book{vijayan_naik_raghunathan_iyer_2017, title={Contactless power transfer system and method for controlling the same}, url={https://patents.google.com/patent/US20170179769A1/en}, number={US20170179769A1}, author={Vijayan, P. and Naik, R. and Raghunathan, A.K. and Iyer, V.M.}, year={2017}, month={Jun} }
 @article{de_morgan_iyer_ke_zhao_vechalapu_bhattacharya_hopkins_2017, title={Design, package, and hardware verification of a high voltage current switch}, number={99}, journal={IEEE Journal of Emerging and Selected Topics in Power Electronics}, publisher={IEEE}, author={De, Ankan and Morgan, Adam and Iyer, Vishnu Mahadeva and Ke, Haotao and Zhao, Xin and Vechalapu, Kasunaidu and Bhattacharya, Subhashish and Hopkins, Douglas C}, year={2017} }
 @inproceedings{iyer_gulur_bhattacharya_2017, title={Hybrid control strategy to extend the ZVS range of a dual active bridge converter}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85020000052&partnerID=MN8TOARS}, DOI={10.1109/APEC.2017.7930979}, abstractNote={This paper presents a hybrid control strategy for a dual active bridge (DAB) based dc-dc converter which combines the benefits of traditional phase shift and burst mode modulation schemes. The advantage of using such a control strategy stems from the fact that it can extend the zero voltage switching (ZVS) range of all power switches in both the primary and secondary bridges when there is a wide variation in input or output voltage. In addition, the hybrid control strategy improves the light load efficiency of the DAB converter. The paper focuses on the development of the average and small signal models for the DAB converter with the hybrid modulation scheme. Digital implementation considerations of the hybrid control scheme are discussed. The effectiveness of the proposed control strategy has been tested and validated through simulations and experiments.}, booktitle={2017 IEEE Applied Power Electronics Conference and Exposition (APEC)}, author={Iyer, V. M. and Gulur, S. and Bhattacharya, S.}, year={2017}, month={Mar}, pages={2035–2042} }
 @inproceedings{iyer_gulur_bhattacharya_2017, title={Optimal design methodology for dual active bridge converter under wide voltage variation}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85028592472&partnerID=MN8TOARS}, DOI={10.1109/itec.2017.7993306}, abstractNote={Dual active bridge (DAB) converter is a popular topology for bidirectional on-board electric vehicle (EV) charger systems and other energy storage applications. In such systems, wide variation in the battery voltage makes design of the DAB converter non-trivial. The focus of this paper is on the optimal selection of DAB parameters when there is a wide variation in the output voltage. Different optimal strategies based on a minimal Euclidean norm approach, namely ‘minimal rms current design’, ‘minimal peak current design’ and ‘minimal power loss design’ are compared to illustrate the effect on system performance with output voltage variation. The proposed optimal design approaches are shown to be superior to a conventional design approach. A loss model for the DAB converter that can be used in the optimal design process is presented. The proposed optimal strategies are validated with experimental results using a laboratory prototype.}, booktitle={2017 ieee transportation electrification conf and expo (itec)}, author={Iyer, V. M. and Gulur, S. and Bhattacharya, S.}, year={2017}, pages={413–420} }
 @inproceedings{iyer_gulur_bhattacharya_2017, title={Small-signal modeling and stability analysis of a bidirectional electric vehicle charger}, DOI={10.1109/icrera.2017.8191214}, abstractNote={This paper addresses the stability challenges that exist in a bidirectional grid connected electric vehicle (EV) charger. The EV charger under consideration comprises of an ac-dc single phase active rectifier stage followed by a dc-dc dual active bridge (DAB) stage. small-signal models suited for stability analysis of this charger are derived. Controller design considerations are discussed in order to ensure closed loop stability of individual stages and to prevent any instability due to interaction between the stages. Experimental results on an EV charger hardware prototype are presented to validate the proposed models and control design considerations.}, booktitle={2017 ieee 6th international conference on renewable energy research and applications (icrera)}, author={Iyer, V. M. and Gulur, S. and Bhattacharya, S.}, year={2017}, pages={1030–1035} }
 @book{vijayan_prabhakaran_collins_iyer_2017, title={System and method for fault ride through}, url={https://patents.google.com/patent/US20170141570A1/en}, number={US20170141570A1}, author={Vijayan, P. and Prabhakaran, S. and Collins, J.O. and Iyer, V.M.}, year={2017}, month={May} }
 @inproceedings{iyer_gulur_bhattacharya_2017, title={Variable DC bus control for a bidirectional on-board electric vehicle charger}, DOI={10.1109/icrera.2017.8191216}, abstractNote={In this paper, a variable dc bus control strategy is evaluated for a bidirectional grid connected electric vehicle (EV) charger topology. The EV charger under consideration comprises of an ac-dc 3-φ active rectifier stage followed by a dc-dc dual active bridge (DAB) converter. The voltage of the common dc-link between the ac-dc stage and the dc-dc stage is regulated such that it follows the voltage variations of the battery pack. The proposed control strategy helps to minimize circulating reactive currents in the DAB converter and extends the soft-switching operating range of the same to achieve high system efficiency. An optimal design approach is presented to select the DAB converter parameters that can be used in conjunction with the variable dc bus control strategy. Experimental results on a 3.3 kW EV charger hardware prototype validate the benefits of the variable dc bus control and proposed optimal design methodology.}, booktitle={2017 ieee 6th international conference on renewable energy research and applications (icrera)}, author={Iyer, V. M. and Gulur, S. and Bhattacharya, S.}, year={2017}, pages={1041–1046} }
 @inproceedings{de_morgan_mahadeva iyer_ke_zhao_vechalapu_bhattacharya_hopkins_2016, title={Design, package, and hardware verification of a high voltage current switch}, booktitle={Applied Power Electronics Conference and Exposition (APEC), 2016 IEEE}, author={De, Ankan and Morgan, Adam and Mahadeva Iyer, Vishnu and Ke, Haotao and Zhao, Xin and Vechalapu, Kasunaidu and Bhattacharya, Subhashish and Hopkins, Douglas C.}, year={2016}, pages={295–302} }
 @inproceedings{iyer_prabhakaran_vijayan_2015, title={High-frequency, high-current transformer designs for Silicon Carbide based LLC converters}, DOI={10.1109/ECCE.2015.7310454}, abstractNote={The introduction of 1200 V Silicon Carbide (SiC) based technologies has enabled the use of high performance LLC converters for high input voltage (>500 VDC) applications such as datacenter power conversion. In this paper, we describe performance of the magnetics for a 2 kW-level LLC converter, operating at 100 kHz with SiC devices. We present magnetics designed for high converter efficiencies (> 96%) at high-current outputs (65 A). We focus on the design considerations to minimize the leakage inductance of a center-tapped transformer with a high voltage transformation ratio. We present a variety of winding strategies and show the efficacy of a hybrid solution that combines foil windings with litz winding for the application described. We demonstrate the performance improvements through finite element simulations and measurements from several prototypes.}, booktitle={2015 IEEE Energy Conversion Congress and Exposition (ECCE)}, author={Iyer, V. M. and Prabhakaran, S. and Vijayan, P.}, year={2015}, month={Sep}, pages={5650–5656} }
 @article{iyer_john_2015, title={Low-frequency dc bus ripple cancellation in single phase pulse-width modulation inverters}, volume={8}, ISSN={1755-4543}, url={https://digital-library.theiet.org/content/journals/10.1049/iet-pel.2014.0320}, DOI={10.1049/iet-pel.2014.0320}, abstractNote={This study presents a topology for a single-phase pulse-width modulation (PWM) converter which achieves low-frequency ripple reduction in the dc bus even when there are grid frequency variations. A hybrid filter is introduced to absorb the low-frequency current ripple in the dc bus. The control strategy for the proposed filter does not require the measurement of the dc bus ripple current. The design criteria for selecting the filter components are also presented in this study. The effectiveness of the proposed circuit has been tested and validated experimentally. A smaller dc-link capacitor is sufficient to keep the low-frequency bus ripple to an acceptable range in the proposed topology.}, number={4}, journal={IET Power Electronics}, publisher={Institution of Engineering and Technology (IET)}, author={Iyer, Vishnu Mahadeva and John, Vinod}, year={2015}, month={Feb}, pages={497–506} }
 @phdthesis{vishnu_2013, title={DC Bus Current Ripple Management in Single Phase PWM Inverters}, author={Vishnu, M}, year={2013} }
 @book{iyer_2013, place={Bangalore, India}, title={DC Bus Current Ripple Management in Single Phase PWM Inverters }, url={http://www.ee.iisc.ac.in/new/people/faculty/vjohn/pdf/ME2013_VishnuM.pdf}, institution={Indian Institute of Science Bangalore}, author={Iyer, V.M.}, year={2013}, month={Jun} }