@article{bhattacharya_narwal_shah_baliga_agarwal_kanale_han_hopkins_cheng_2023, title={Power Conversion Systems Enabled by SiC BiDFET Device}, volume={10}, ISSN={["2329-9215"]}, url={https://doi.org/10.1109/MPEL.2023.3237060}, DOI={10.1109/MPEL.2023.3237060}, abstractNote={The BiDirectional Field-Effect Transistor (BiDFET) can enable circuit topologies requiring four-quadrant switches, that were earlier designed using discrete combinations of MOSFETs, IGBTs, GaN HEMTs, and PiN diodes. The monolithic nature of the BiDFET allows lower device count, smaller switch volume, lower inductance, and simpler packaging, and hence more reliable and commercially viable implementation in power electronics converters. The matrix converter topologies, now feasible using BiDFETs, can eliminate the bulky and unreliable dc link capacitors or inductors required for conventional voltage-source or current-source converters in ac–ac and ac–dc applications. The 1.2 kV BiDFET has the potential to disrupt all the applications utilizing 1.2 kV switches, including electric vehicle (EV) drivetrain, bidirectional EV chargers, industrial motor drives, solid-state transformers, datacenter power supplies, elevator drives, dc microgrids, energy storage grid integration, solid-state breakers, etc.}, number={1}, journal={IEEE POWER ELECTRONICS MAGAZINE}, author={Bhattacharya, Subhashish and Narwal, Ramandeep and Shah, Suyash Sushilkumar and Baliga, B. Jayant and Agarwal, Aditi and Kanale, Ajit and Han, Kijeong and Hopkins, Douglas C. and Cheng, Tzu-Hsuan}, year={2023}, month={Mar}, pages={39–43} }
 @article{rastogi_shah_singh_bhattacharya_2023, title={Vector-Based Open-Circuit Fault Diagnosis Technique for a Three-Phase DAB Converter}, volume={9}, ISSN={["1557-9948"]}, url={https://doi.org/10.1109/TIE.2023.3312430}, DOI={10.1109/TIE.2023.3312430}, abstractNote={A three-phase dual active bridge (DAB3) has become a popular topology for high-power dc–dc conversion. An open-circuit fault in DAB3 can produce a dc bias in its phase currents, which can saturate the transformer, resulting in the device overcurrents and catastrophic failure. This letter proposes a robust fault diagnosis technique to detect the fault and identify the faulty transistor within three to four switching cycles with high noise immunity. The technique requires low-bandwidth current sensing only on one side of the transformer, providing a cost and design benefit, especially in the case of a high-gain high-power converter, where the currents can be sensed on the low-current side. Moreover, in dual-active-bridge circuits, where current sensing is a norm for control and protection purposes, the proposed algorithm can be deployed as a software update on the existing hardware and does not require any hardware modifications. Experimental verification results of the proposed technique on a 5-kW DAB3 hardware prototype are also presented.}, journal={IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS}, author={Rastogi, Sagar Kumar and Shah, Suyash Sushilkumar and Singh, Brij N. and Bhattacharya, Subhashish}, year={2023}, month={Sep} }
 @inproceedings{kanale_narasimhan_cheng_agarwal_shah_baliga_bhattacharya_hopkins_2021, title={Comparison of the Capacitances and Switching Losses of 1.2 kV Common-Source and Common- Drain Bidirectional Switch Topologies}, ISBN={9781665401821}, url={http://dx.doi.org/10.1109/WiPDA49284.2021.9645130}, DOI={10.1109/WiPDA49284.2021.9645130}, abstractNote={Bidirectional, or four-quadrant switches (FQS) can be designed as back-to-back MOSFETs connected in common-drain (CD) or common-source (CS) topologies. CDFQS and CS-FQS assembled from discrete 1.2 kV commercially available SiC power MOSFETs were characterized to obtain capacitance and switching loss values. The CD-FQS exhibited a 1. 17x larger turn-on loss compared to the CS-FQS, while the CS-FQS exhibited a 1. 52x larger turn-off loss compared to the CD-FQS. The CS-FQS exhibited a lower input capacitance, while the CD-FQS exhibited a lower output and reverse transfer capacitance.}, booktitle={2021 IEEE 8th Workshop on Wide Bandgap Power Devices and Applications (WiPDA)}, publisher={IEEE}, author={Kanale, Ajit and Narasimhan, Sneha and Cheng, Tzu-Hsuan and Agarwal, Aditi and Shah, Suyash Sushilkumar and Baliga, B. Jayant and Bhattacharya, Subhashish and Hopkins, Douglas C.}, year={2021}, pages={112–117} }
 @article{rastogi_shah_singh_bhattacharya_2021, title={Mode Analysis and Identification Scheme of Open-Circuit Fault in a Three-phase DAB Converter}, ISSN={["2329-3721"]}, DOI={10.1109/ECCE47101.2021.9595447}, abstractNote={The three-phase Dual Active Bridge (3$-\Phi$ DAB) is a popular DC-DC converter topology for high power applications; it provides high efficiency, bidirectional power transfer capability with galvanic isolation between the input/output terminals. With the wide-scale adoption of such power electronic converters, their reliability becomes increasingly important. A prominent failure mode in the high power converters is the open-circuit fault that occurs due to failure in a semiconductor device or its gate drive circuit. In this study, detailed waveform analyses are presented for the normal and the fault mode operation of the $3-\Phi$ DAB. Main symptoms of the converter during normal and fault conditions have been identified, and a unique pattern in the DC bias of phase currents under fault mode is noted. A logic-based fault diagnosis scheme is proposed to detect the fault and identify the faulty transistor. The scheme requires sensing of currents on only one side of the transformer to detect faults on either side. Therefore, lower-rated current sensors may be placed on the low current side of the high-gain converters, thereby reducing the cost. Moreover, the detection scheme relies only on the DC bias value of the phase currents, implying that low-bandwidth current sensors can be used. Experimental results at 5.5 kW rated power have been provided to verify the analyses and the proposed identification scheme. The study also reveals a new potential benefit of the 3$-\Phi$ DAB converter over the 1$-\Phi$ DAB; i.e., even in the presence of a secondary-side open-circuit fault, the 3$-\Phi$ converter may continue to operate normally. The analyses and the open-circuit fault diagnosis scheme proposed for the 3$-\Phi$ DAB converter will improve the system’s reliability.}, journal={2021 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE)}, author={Rastogi, Sagar Kumar and Shah, Suyash Sushilkumar and Singh, Brij N. and Bhattacharya, Subhashish}, year={2021}, pages={2762–2769} }
 @article{shah_narwal_bhattacharya_kanale_cheng_mehrotra_agarwal_baliga_hopkins_2021, title={Optimized AC/DC Dual Active Bridge Converter using Monolithic SiC Bidirectional FET (BiDFET) for Solar PV Applications}, ISSN={["2329-3721"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85123361428&partnerID=MN8TOARS}, DOI={10.1109/ECCE47101.2021.9595533}, abstractNote={Grid interface power conversion systems for commercial, industrial and residential solar power generation are becoming ubiquitous due to the competitive cost of solar energy. The AC/DC dual active bridge (DAB) converter is an upcoming topology in industrial PV energy and energy storage applications, providing bidirectional power transfer and galvanic isolation. In this paper, the properties of a DAB-type converter are leveraged to propose a design optimization process. It can optimize the high-frequency RMS current, size of magnetic elements and zero-voltage-switching (ZVS) region of the converter. The resulting design is compared against that derived from a conventional approach. In addition, an algorithm to compute the harmonic currents at the DC and line frequency AC ports of the system is proposed, and the respective filter designs are presented. The optimized design of the AC/DC DAB converter is implemented using the newly developed, 1200 V, $46 \mathrm{m}\Omega$, four quadrant, SiC-based monolithic bidirectional FETs (BiDFET). Experimental results from the 2.3 kW, $400\mathrm{V}/277\mathrm{V}_{{\mathrm {RMS}}}$ hardware prototype are finally presented to verify the design process.}, journal={2021 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE)}, author={Shah, Suyash Sushilkumar and Narwal, Ramandeep and Bhattacharya, Subhashish and Kanale, Ajit and Cheng, Tzu-Hsuan and Mehrotra, Utkarsh and Agarwal, Aditi and Baliga, B. Jayant and Hopkins, Douglas C.}, year={2021}, pages={568–575} }
 @article{das_satpathy_shah_bhattacharya_veliadis_2021, title={Paralleling of Four 650V/60A GaN HEMTs for High Power Traction Drive Applications}, ISSN={["2329-3721"]}, DOI={10.1109/ECCE47101.2021.9595766}, abstractNote={This paper presents design considerations and experimental verification of a GaN-based half-bridge 650V/160A power converter block with four parallel 650V/60AGaN High Electron Mobility Transistors (HEMTs) for high-power traction drive applications. Paralleling of semiconductor devices is common for high power density applications. However, paralleling more than two GaN devices is challenging as parasitic inductances and resistances need to be well matched for all the devices. In addition, the DC loop inductances must be minimized to reduce the device voltage overshoot during turn-off. The gate loop inductances must also be matched and minimized to improve current sharing and reduce gate voltage oscillations. A detailed design method of a half-bridge with four parallel devices is discussed in this paper for matching gate and DC loop inductances. A half-bridge test circuit with four parallel enhancement-mode GaN (e-GaN) HEMTs is designed following the design method. The inductance matchings are verified with a detailed Q3D simulation. Finally, Double Pulse Test (DPT) results at 400V/160A are presented in this paper to demonstrate the half-bridge converter block’s current sharing and loss distributions.}, journal={2021 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE)}, author={Das, Partha Pratim and Satpathy, Subhransu and Shah, Suyash Sushilkumar and Bhattacharya, Subhashish and Veliadis, Victor}, year={2021}, pages={5269–5276} }
 @article{shah_rastogi_bhattacharya_2021, title={Paralleling of LLC Resonant Converters}, volume={36}, ISSN={["1941-0107"]}, url={https://doi.org/10.1109/TPEL.2020.3040621}, DOI={10.1109/TPEL.2020.3040621}, abstractNote={The LLC resonant converter is a popular, variable switching frequency dc--dc converter that may be controlled using two methods: charge and frequency control. In this article, the application of LLC resonant converters to input-parallel, output-parallel system is studied. In this respect, the models of output-port I-V characteristics and small-signal output impedance of the charge controlled LLC converter are proposed. In addition, a mathematical framework is developed for droop-based paralleled dc--dc systems. It distinctly identifies the output dc voltage and circulating current modes of stability, even in systems comprising of nonidentical converters. The developed model and the analytical framework are utilized to study the two modes of stability in droop-based parallel-connected LLC converters. It finds the circulating current mode instability for both the charge and frequency control methods, despite a stable output dc bus voltage. The instability inhibits fast response and high closed-loop bandwidth, eroding the reported advantages of the charge control method over frequency control. Further investigation into the output port I-V characteristics reveals the superiority of charge-controlled LLC converters in paralleled systems than the conventional frequency-controlled converters. A novel application of “common inner reference” based “automatic load sharing” strategy is developed and uniquely applied to the charge controlled system. In addition, the effects of component tolerance and communication delay on this strategy are also briefly explored. The theoretical output-port models and the stability analyses of parallel-connected LLC resonant converters are validated through experiments on a hardware prototype. Further, the supplementary video files illustrate the advantage of the charge control method over frequency control in such system. Finally, the proposed automatic load sharing strategy is validated in steady-state and through a step-change in load.}, number={6}, journal={IEEE TRANSACTIONS ON POWER ELECTRONICS}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Shah, Suyash Sushilkumar and Rastogi, Sagar Kumar and Bhattacharya, Subhashish}, year={2021}, month={Jun}, pages={6276–6287} }
 @inproceedings{kanale_cheng_shah_han_agarwal_baliga_hopkins_bhattacharya_2021, title={Switching Characteristics of a 1.2 kV, 50 mΩ SiC Monolithic Bidirectional Field Effect Transistor (BiDFET) with Integrated JBS Diodes}, ISBN={9781728189499}, ISSN={["1048-2334"]}, url={http://dx.doi.org/10.1109/apec42165.2021.9487410}, DOI={10.1109/APEC42165.2021.9487410}, abstractNote={The switching performance of large area (1cm x 1cm) monolithic 1.2 kV 50 mΩ 4H-SiC bidirectional field effect transistor (BiDFET) with integrated JBS diodes is reported for the first time. The devices were fabricated in a 6-inch commercial foundry and then packaged in a custom-designed four-terminal module. The switching performance of the BiDFET has been observed to be 1.4x better than that of its internal JBSFETs. Dynamic characterization was performed at 800 V with different gate resistances, current levels and case temperatures. An increase in switching losses was observed for the BiDFET with increasing gate resistance and current level as observed for SiC power MOSFETs. The BiDFET showed a 9% reduction in total switching loss from 25 °C to 150 °C with a current of 10 A.}, booktitle={2021 IEEE Applied Power Electronics Conference and Exposition (APEC)}, publisher={IEEE}, author={Kanale, Ajit and Cheng, Tzu-Hsuan and Shah, Suyash Sushilkumar and Han, Kijeong and Agarwal, Aditi and Baliga, B. Jayant and Hopkins, Douglas and Bhattacharya, Subhashish}, year={2021}, month={Jun}, pages={1267–1274} }
 @article{shah_bhattacharya_2019, title={A Simple Unified Model for Generic Operation of Dual Active Bridge Converter}, volume={66}, ISSN={["1557-9948"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85049465467&partnerID=MN8TOARS}, DOI={10.1109/TIE.2018.2850012}, abstractNote={This paper presents a simple and generic model of a dual active bridge converter valid throughout its range of operation. It is suitable for all operating modes and modulation strategies such as phase-shift, extended phase-shift, dual phase-shift, or triple phase-shift modulation. It hypothesizes that any mode of its operation characterized by the duty ratios (<inline-formula><tex-math notation="LaTeX">$d_1$</tex-math></inline-formula>, <inline-formula><tex-math notation="LaTeX">$d_2$</tex-math></inline-formula>) of the two full-bridge converter ac voltages and the phase shift (<inline-formula><tex-math notation="LaTeX">$\phi$</tex-math></inline-formula>) between them can be decomposed into four parallel dual active bridge circuits operating in simple phase-shift modulation. The hypothesis is proven mathematically; the average and small-signal models are derived and validated through simulations and experiments on a hardware prototype.}, number={5}, journal={IEEE TRANSACTIONS ON INDUSTRIAL ELECTRONICS}, publisher={Institute of Electrical and Electronics Engineers (IEEE)}, author={Shah, Suyash Sushilkumar and Bhattacharya, Subhashish}, year={2019}, month={May}, pages={3486–3495} }
 @inproceedings{kumar_ravichandran_singh_shah_bhattacharya_2017, title={An intelligent medium voltage gate driver with enhanced short circuit protection scheme for 10kV 4H-SiC MOSFETs}, volume={2017-January}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85041440358&partnerID=MN8TOARS}, DOI={10.1109/ecce.2017.8096486}, abstractNote={Designing of gate drivers for high voltage SiC power devices in medium voltage applications is challenging due to high dv/dt and di/dt at the switching instants. During short circuit fault, the device current rises with high di/dt, and eventually the device fails within few of micro seconds if not protected. Short circuit protection of power devices is an essential feature to improve reliability of converters. In this paper, a novel gate driver is developed with short circuit protection scheme, suitable for 10kV, 10A 4-H SiC MOSFETs. It utilizes the de-sat sensing scheme to detect the fault, and clears the fault by turning off the gate pulse in two stages. The trip time at the short circuit fault is much smaller than the short circuit withstanding time of 10kV 4H-SiC MOSFETs. The gate driver is qualified with appropriate experimental test bench for validation of short circuit protection feature, over-current limit and continuous operation for the 10kV MOSFETs.}, booktitle={2017 IEEE Energy Conversion Congress and Exposition, ECCE 2017}, author={Kumar, A. and Ravichandran, A. and Singh, S. and Shah, S. and Bhattacharya, Subhashish}, year={2017}, pages={2560–2566} }