@article{narasimhan_sisson_leslie_parmar_rastogi_bhattacharya_2023, title={Design Considerations of a 3.3 kV SiC-based Reverse Voltage Blocking Module for Current Source Inverter Application}, ISSN={["1048-2334"]}, DOI={10.1109/APEC43580.2023.10131381}, abstractNote={This paper presents the design and development of a 3.3 kV silicon carbide (SiC) based reverse voltage blocking half-bridge module for the first time. This low inductance module can build a single-phase or a three-phase current source inverter (CSI). The module comprises of a SiC-MOSFET (3.3 kV/50 A die) and a SiC-MPS diode (3.3 kV/50 A die) to form a 3.3 kV SiC-based current switch in the half-bridge configuration. The static characterization of the current switch (CS) is performed, and a double pulse test circuit is used to verify the switching performance of the developed module. Additionally, the inverter efficiency is estimated for a 30 kW three-phase CSI for a motor drive application, using the obtained static and dynamic characterization results. The impact of the module inductances on the switch voltage and currents is discussed, thus illustrating the importance of a module-based design for CSI applications.}, journal={2023 IEEE APPLIED POWER ELECTRONICS CONFERENCE AND EXPOSITION, APEC}, author={Narasimhan, Sneha and Sisson, Colton and Leslie, Scott and Parmar, Keval and Rastogi, Sagar Kumar and Bhattacharya, Subhashish}, year={2023}, pages={350–357} }
 @article{rastogi_shah_singh_bhattacharya_2023, title={Mode Analysis, Transformer Saturation, and Fault Diagnosis Technique for an Open-Circuit Fault in a Three-Phase DAB Converter}, volume={38}, ISSN={["1941-0107"]}, url={https://doi.org/10.1109/TPEL.2023.3241654}, DOI={10.1109/TPEL.2023.3241654}, abstractNote={The three-phase dual active bridge (DAB3) is a popular dc–dc converter topology for high-power applications, capable of high-efficiency bidirectional power transfer with galvanic isolation. A single point of failure in power converters is the open-circuit fault (OCF) due to failure in a semiconductor device or its gate drive circuit. This study presents detailed waveform analyses for the normal- and the fault-mode operation. A novel logic-based fault diagnosis scheme is proposed based on the unique pattern in the dc bias of phase currents. Unlike previous schemes, the proposed scheme requires low-bandwidth current sensing only one side of the transformer to detect faults on either side, providing a cost and design benefit. Experimental results verify the analyses and the proposed identification scheme, detecting the fault within a few switching cycles. An in-depth study of the transformer under fault mode is presented for the first time, setting a guideline of time available for fault diagnosis and response. Experimental B–H curves and magnetizing currents of the three-phase transformer illustrate the cycle-by-cycle progression toward core saturation under fault mode. The study also reveals a new potential benefit of the three-phase DAB over the single-phase DAB; i.e., even in the presence of a secondary-side OCF, the DAB3 may continue to operate normally at full load.}, number={6}, journal={IEEE TRANSACTIONS ON POWER ELECTRONICS}, author={Rastogi, Sagar Kumar and Shah, Suyash Sushilkumar and Singh, Brij N. and Bhattacharya, Subhashish}, year={2023}, month={Jun}, pages={7644–7660} }
 @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} }
 @article{narasimhan_rastogi_bhattacharya_2022, title={Short-Circuit Fault Diagnosis of a Three-Phase Current-Source Inverter}, ISSN={["2329-3721"]}, DOI={10.1109/ECCE50734.2022.9947610}, abstractNote={The development of the wide-band gap devices has led to the re-emergence of current-source inverters (CSIs). With the modernization of future power systems, the importance of the reliability of power converters is critical. Fault identification is vital to enhancing the reliability of the system. A prominent failure mode in power converters occurs due to the semiconductor device failure. The normal and fault mode operation of the converter is discussed for the three short-circuit fault conditions observed in current-source inverters. This paper proposes a method to detect and locate the short-circuit fault of a MOSFET switch, a diode switch, and a current switch comprising of both MOSFET and diode simultaneously, in a CSI. A fault detection method that involves checking the ratio of the average value of the ac currents and average value of the reference currents in one fundamental cycle to threshold limits is used to detect and identify the location of the fault. This method does not need additional voltage or current sensors for implementing the proposed algorithm. The effectiveness of the proposed method is shown in simulation and experimental results are provided to validate the same. This proposed method for fault identification improves the system reliability of CSIs.}, journal={2022 IEEE ENERGY CONVERSION CONGRESS AND EXPOSITION (ECCE)}, author={Narasimhan, Sneha and Rastogi, Sagar Kumar and Bhattacharya, Subhashish}, year={2022} }
 @article{rastogi_rana_mishra_2021, title={A Single-Input Multiple-Output Unity Power Factor Rectifier}, volume={36}, ISSN={["1941-0107"]}, DOI={10.1109/TPEL.2020.3045130}, abstractNote={The increasing consumer electronics, most of which are natively dc loads, demand efficient power conversion from input ac grid to dc loads. Good power quality and unity power factor (UPF) for maintaining a stable grid can be achieved using power factor correction (PFC) circuits. This article proposes a family of single-input multiple-output (SIMO) rectifiers, which can provide one dc output higher and multiple dc outputs lower than the peak voltage of the ac input. Compared to separate conventional rectifiers at every point-of-load, each with a boost-based PFC circuit followed by a buck converter, the proposed topology requires a less number of switches and has inherent shoot-through protection. In this article, the operation of an N-output (N-switch) rectifier is explained, and its general large-signal and small-signal models are developed. It is further illustrated using a single-input dual-output (SIDO) rectifier. Of the two dc outputs, one dc output voltage is higher, and one is lower than the peak voltage of the ac input. The small-signal model and the control scheme to enforce output voltage regulation and UPF operation are discussed. Experimental results are provided to validate the proposed topology and the control scheme.}, number={9}, journal={IEEE TRANSACTIONS ON POWER ELECTRONICS}, author={Rastogi, Sagar Kumar and Rana, Mandeep Singh and Mishra, Santanu K.}, year={2021}, month={Sep}, pages={10127–10141} }
 @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_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} }
 @article{rastogi_sankar_manglik_mishra_mohanty_2019, title={Toward the Vision of All-Electric Vehicles in a Decade}, volume={8}, ISSN={["2162-2256"]}, DOI={10.1109/MCE.2018.2880848}, abstractNote={Consumers, manufacturers, and inventors have been pondering the idea of electrifying transportation for decades, but engines on the road remain largely based on fossil fuel. Alternate technologies like hydrogen fuel cells and biofuels have been on the near horizon for years. Despite the advent of various strong policy incentives, electric vehicles (EVs) have had limited success in the market. However, a recent surge in battery technologies and other market forces have combined to pose a serious threat to the centuries-old internal combustion engine vehicles. Anticipating significant EV penetration into the transportation sector, this article discusses various aspects and key challenges of charging battery electric vehicles (BEVs).}, number={2}, journal={IEEE CONSUMER ELECTRONICS MAGAZINE}, author={Rastogi, Sagar K. and Sankar, Arun and Manglik, Kushagra and Mishra, Santanu K. and Mohanty, Saraju P.}, year={2019}, month={Mar}, pages={103–107} }