@article{tripathi_mainali_madhusoodhanan_kadavelugu_vechalapu_hatua_2017, title={A Novel ZVS range enhancement technique of a high-voltage dual active bridge converter using series injection}, volume={32}, number={6}, journal={IEEE Transactions on Power Electronics}, author={Tripathi, A. K. and Mainali, K. and Madhusoodhanan, S. and Kadavelugu, A. and Vechalapu, K. and Hatua, K.}, year={2017}, pages={4231–4245} }
 @article{vechalapu_bhattacharya_van brunt_ryu_grider_palmour_2017, title={Comparative Evaluation of 15-kV SiC MOSFET and 15-kV SiC IGBT for Medium-Voltage Converter Under the Same dv/dt Conditions}, volume={5}, ISSN={["2168-6777"]}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85012177488&partnerID=MN8TOARS}, DOI={10.1109/jestpe.2016.2620991}, abstractNote={The 15 kV SiC MOSFET and 15 kV SiC IGBT are two state-of-the-art high voltage SiC devices. These high voltage SiC devices enable simple two level converters for medium voltage source converter compared to the complex three level and multilevel topologies with Silicon devices. This paper presents the detailed experimental results for the characterization of 15 kV SiC MOSFET module at 10 kV and 12 kV DC bus for two different configuration of device under test. This paper also presents the switching loss comparison of 15 kV SiC MOSFET with 15 kV SiC IGBT for the same dv/dt. Based on loss data obtained from experiments, this paper finally reports the switching frequency limits of 15 kV SiC MOSFET for 10 kV DC bus, 3-Phase two level converter and Bi-directional DC-DC phase leg converter with 10 kV output voltage and comparative evaluation of 15 kV SiC MOSFET and 15 kV SiC IGBT for the same dv/dt in a unidirectional DC-DC boost hard switching converter for 10 kV output voltage.}, number={1}, journal={IEEE JOURNAL OF EMERGING AND SELECTED TOPICS IN POWER ELECTRONICS}, author={Vechalapu, Kasunaidu and Bhattacharya, Subhashish and Van Brunt, Edward and Ryu, Sei-Hyung and Grider, Dave and Palmour, John W.}, year={2017}, month={Mar}, pages={469–489} }
 @inproceedings{tripathi_mainali_madhusoodhanan_yadav_vechalapu_bhattacharya_2016, title={A MV intelligent gate driver for 15kV SiC IGBT and 10kV SiC MOSFET}, volume={2016-May}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84973596466&partnerID=MN8TOARS}, DOI={10.1109/apec.2016.7468153}, abstractNote={This paper presents an Intelligent Medium-voltage Gate Driver (IMGD) for 15kV SiC IGBT and 10kV SiC MOSFET devices. The high voltage-magnitude and high dv/dt(> 30kV/μs) of these MV SiC devices, pose design challenge in form of isolation and EMI. This problem is solved by development of a <; 1pF isolation capacitance power-supply. But due to applied high stress, smaller short-circuit withstand time and the criticality of the application, these devices need to be monitored, well protected, active gate-driven and safely shut-down. This paper presents an EMI hardened IMGD built around a CPLD, sensing and optical interfacing unit. It provides advanced gate-driving, added protection and optically isolated state-monitoring features. The device operating conditions such as module temperature and Vds(on) can be data-logged. They can be used for diagnosis/prognosis purposes such as to predict failure and safely shut-down the system. This paper describes the functionality of different building blocks. The 15kV SiC IGBT has higher second switching slope above its punch-through level which is moderated without increasing losses by using digitally controlled active gate-driving. The shoot-through protection time can be reduced below withstand time by advanced gate driving. Soft turn-on and over-current triggered gate-voltage reduction helps reducing blanking time and quick turn-off reduces the protection response time. In this paper, the IMGD is high side tested at 5kV with device state monitoring on. The active gate-driving is tested at 6kV.}, booktitle={Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC}, author={Tripathi, A. and Mainali, K. and Madhusoodhanan, S. and Yadav, A. and Vechalapu, K. and Bhattacharya, Subhashish}, year={2016}, pages={2076–2082} }
 @inproceedings{madhusoodhanan_mainali_tripathi_kadavelugu_vechalapu_patel_bhattacharya_2016, title={Comparative evaluation of 15 kV SiC IGBT and 15 kV SiC MOSFET for 3-phase medium voltage high power grid connected converter applications}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85015416448&partnerID=MN8TOARS}, DOI={10.1109/ecce.2016.7854933}, abstractNote={The advent of high voltage (HV) wide band-gap power semiconductor devices has enabled the medium voltage (MV) grid tied operation of non-cascaded neutral point clamped (NPC) converters. This results in increased power density, efficiency as well as lesser control complexity. The multi-chip 15 kV/40 A SiC IGBT and 15 kV/20 A SiC MOSFET are two such devices which have gained attention for MV grid interface applications. Such converters based on these devices find application in active power filters, STATCOM or as active front end converters for solid state transformers. This paper presents an experimental comparative evaluation of these two SiC devices for 3-phase grid connected applications using a 3-level NPC converter as reference. The IGBTs are generally used for high power applications due to their lower conduction loss while MOSFETs are used for high frequency applications due to their lower switching loss. The thermal performance of these devices are compared based on device loss characteristics, device heat-run tests, 3-level pole heat-run tests, PLECS thermal simulation based loss comparison and MV experiments on developed hardware prototypes. The impact of switching frequency on the harmonic control of the grid connected converter is also discussed and suitable device is selected for better grid current THD.}, booktitle={ECCE 2016 - IEEE Energy Conversion Congress and Exposition, Proceedings}, author={Madhusoodhanan, S. and Mainali, K. and Tripathi, A. and Kadavelugu, A. and Vechalapu, K. and Patel, D. and Bhattacharya, Subhashish}, year={2016} }
 @inproceedings{vechalapu_negi_bhattacharya_2016, title={Comparative performance evaluation of series connected 15 kV SiC IGBT devices and 15 kV SiC MOSFET devices for MV power conversion systems}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85015367464&partnerID=MN8TOARS}, DOI={10.1109/ecce.2016.7854936}, abstractNote={The 10–15kV SiC MOSFET and 15kV SiC IGBT (2 μm and 5 μm buffer layer) are the state of the art high voltage devices designed by Cree Inc. These devices are expected to increase the power density of converters and the demonstration of these devices in applications like Solid State Transformers (SST) have been reported up to 4.16 kV–13.2 kV grid connection. It is interesting to investigate the performance of the devices in very high voltage (≥13.2 kV) application, where the series connection of devices is required. Therefore, this paper addresses design considerations of the series connection of 15 kV Silicon Carbide (SiC) IGBT devices and a series connection of 10 kV/15 kV Silicon Carbide (SiC) MOSFET devices in two separate independent cases and their experimental comparison.}, booktitle={ECCE 2016 - IEEE Energy Conversion Congress and Exposition, Proceedings}, author={Vechalapu, K. and Negi, A. and Bhattacharya, Subhashish}, year={2016} }
 @inproceedings{mainali_madhusoodhanan_tripathi_vechalapu_de_bhattacharya_2016, title={Design and evaluation of isolated gate driver power supply for medium voltage converter applications}, volume={2016-May}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84973644285&partnerID=MN8TOARS}, DOI={10.1109/apec.2016.7468085}, abstractNote={The commercial gate drivers are available upto 6.5 kV IGBTs. With the advances in the SiC, power devices rated beyond 10 kV are being researched. These devices will have use on medium voltage power converters. Commercial gate drivers rated for such high voltages are not available. These power devices have very high dv/dts (30-100 kV/μs) at switching transitions. Such high dv/dts bring in challenges in the gate driver design. The isolation stage of the gate power supply needs to have very low coupling capacitance to limit the high frequency circulating currents from reaching the gate driver control circuits. Also, the isolation stage has to be designed with insulation several times higher than the peak system voltage level. In this paper, design, development and evaluation of the gate power supply for medium voltage level applications have been investigated. Several isolation transformer designs have been investigated and optimum design, with very low coupling capacitance ≈ 0.5 pF, has been identified and used in the gate driver design. Experimental characterization of the transformer has been done. The performance of the gate driver power supply has been evaluated in several MV power converters, using 10 kV SiC MOSFETs.}, booktitle={Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC}, author={Mainali, K. and Madhusoodhanan, S. and Tripathi, A. and Vechalapu, K. and De, A. and Bhattacharya, Subhashish}, year={2016}, pages={1632–1639} }
 @inproceedings{de_morgan_iyer_ke_zhao_vechalapu_bhattacharya_hopkins_2016, title={Design, package, and hardware verification of a high voltage current switch}, volume={2016-May}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84973664278&partnerID=MN8TOARS}, DOI={10.1109/apec.2016.7467887}, abstractNote={This paper demonstrates various electrical and package design considerations in series connecting a high-voltage (HV) silicon (Si)-IGBT (6500-V/25-A die) and a silicon carbide-junction barrier Schottky diode (6500-V/25-A die) to form an HV current switch. The effects of connecting the cathode of the series diode to an IGBT collector, versus connecting the IGBT emitter to the anode of the series diode, are analyzed in regards to minimizing the parasitic inductance. An optimized package structure is discussed and an HV current switch module is custom fabricated in the laboratory. An HV double pulse test circuit is used to verify the switching performance of the current switch module. Low-voltage and HV converter prototypes are developed and tested to ensure thermal stability of the same. The main motivation of this paper is to enumerate detailed design considerations for packaging an HV current switch.}, note={\urlhttps://ieeexplore.ieee.org/document/7467887/}, booktitle={Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC}, author={De, A. and Morgan, A. and Iyer, V.M. and Ke, H. and Zhao, X. and Vechalapu, K. and Bhattacharya, Subhashish and Hopkins, D.C.}, year={2016}, pages={295–302} }
 @inproceedings{madhusoodhanan_mainali_tripathi_vechalapu_bhattacharya_2016, title={Medium voltage (≥ 2.3 kV) high frequency three-phase two-level converter design and demonstration using 10 kV SiC MOSFETs for high speed motor drive applications}, volume={2016-May}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84973597838&partnerID=MN8TOARS}, DOI={10.1109/apec.2016.7468066}, abstractNote={High speed variable frequency motor drives are required for marine applications, compressors for oil and gas industries, wind energy generation systems etc. Traditionally, low voltage high speed motor drives are used in such applications. This results in large currents at high power levels leading to large copper loss in the motor winding. Therefore, medium voltage (MV) drives are being considered. The silicon (Si) based MV drives need gears to increase the speed due to low switching frequency operation of Si devices in the converter. Gears reduce both efficiency and power density. With the development of 10 kV SiC MOSFET, high switching frequency at MV is possible, which has enabled the scope of high power density MV direct drive variable speed controlled motors. In this paper, the design of a three-phase, 2-level, ≥ 2.3 kV MV, high frequency converter based on 10 kV SiC MOSEFT is explained. Performance analysis is presented along with experimental demonstration.}, booktitle={Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC}, author={Madhusoodhanan, S. and Mainali, K. and Tripathi, A. and Vechalapu, K. and Bhattacharya, Subhashish}, year={2016}, pages={1497–1504} }
 @inproceedings{vechalapu_bhattacharya_2016, title={Performance comparison of 10 kV#x2013;15 kV high voltage SiC modules and high voltage switch using series connected 1.7 kV LV SiC MOSFET devices}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85015454079&partnerID=MN8TOARS}, DOI={10.1109/ecce.2016.7855339}, abstractNote={. The 10 kV to 15 kV SiC MOSFET and 15 kV SiC IGBT are state of the art high voltage (HV) devices designed by Cree Inc. These devices are expected to increase the power density of converters and are expected to replace 4.5 kV/6.5 kV Si IGBTs. However, these are not commercially available. On the other hand low voltage (LV) 1.7 kV SiC MOSFET is commercially available, and it is replacing existing 1.7 kV Si-IGBT and it can meet immediate need of medium or high voltage (MV or HV) converter applications with series connection of these devices and can replace existing 4.5 kV/6.5 kV Silicon (Si) IGBT. Therefore, 10 kV-15 kV SiC modules and series connected 1.7 kV SiC MOSFET will be competing with each other for MV and HV converter applications. Hence, to explore the capability of low voltage SiC devices for MV or HV applications, a HV switch (10 kV-15 kV) using the series connection of 1.7 kV/300 A SiC MOSFET modules has been investigated. For making HV switch using series connected 1.7 kV SiC MOSFET, a simple RC snubber method has been used for dynamic voltage sharing to offset the turn-off delays due to mismatch of device characteristics and gate signals. Experimental switching characterization with different values of RC snubbers has been carried out, and a methodology has been outlined to find the optimal RC snubber which gives minimum voltage sharing difference, snubber losses and total semiconductor losses. In addition, experimental switching characterization of 10 kV-15 kV SiC modules is presented. Furthermore, a performance comparison of HV 10 kV-15 kV SiC modules and HV switch using series connected 1.7 kV SiC MOSFETs is presented in this paper.}, booktitle={ECCE 2016 - IEEE Energy Conversion Congress and Exposition, Proceedings}, author={Vechalapu, K. and Bhattacharya, Subhashish}, year={2016} }
 @inproceedings{vechalapu_negi_bhattacharya_2016, title={Performance evaluation of series connected 15 kV SiC IGBT devices for MV power conversion systems}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-85015420529&partnerID=MN8TOARS}, DOI={10.1109/ecce.2016.7855343}, abstractNote={The 15kV SiC IGBT (2 μm buffer layer) with chip area of 8.4 × 8.4 mm2 is the state of the art high voltage device designed by Cree Inc. This device is expected to increase the power density of converters and the demonstration of the device in applications like Solid State Transformers has been published. Therefore, it is interesting to investigate the performance of the device in very high voltage (HV) application, where the series connection of devices is required. This paper addresses design considerations of the series connection of 15kV SiC IGBT devices for high voltage converter applications. A simple RC snubber has been used to control both ‘dv/dt’ and dynamic voltage balancing during turn-off. The experimental results show that there is a significant difference in the static and dynamic voltage sharing between two unmatched 15kV SiC IGBTs without active compensation method. With external RC snubber at total DC bus voltage of 10 kV, the difference in dynamic voltage between the two 15 kV SiC IGBT devices during turn-off transition nearly negligible. Also with external snubber, the total turn-off dv/dt of less than ‘5 kV/ μs’ is achieved across each device of two series connected 15kV SiC IGBTs. Furthermore, optimization of RC snubber to minimize semiconductor switching losses and total losses per device including the snubber resistor losses in series connection has been presented.}, booktitle={ECCE 2016 - IEEE Energy Conversion Congress and Exposition, Proceedings}, author={Vechalapu, K. and Negi, A. and Bhattacharya, Subhashish}, year={2016} }
 @inproceedings{tripathi_madhusoodhanan_mainali_vechalapu_bhattacharya_2016, title={Series injection enabled full ZVS light load operation of a 15kV SiC IGBT based dual active half bridge converter}, volume={2016-May}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84973607429&partnerID=MN8TOARS}, DOI={10.1109/apec.2016.7467976}, abstractNote={The 15kV SiC IGBT has second higher dv/dt turn-off slope above the punch-through level resulting in EMI. Increasing gate-resistance also slows the first dv/dt causing increased switching loss. A snubber capacitor assisted turn-off solves these issues for a high power dual active bridge (DAB) converter based on this device, but the light load turn-on ZVS becomes hard to achieve. This paper proposes a series injection enabled triangular current shaping at the light load turn-off instant in the DAB to create enough current for smooth free-wheeling transition of device voltage during the dead-time period for ZVS turn-on. The proposed technique is validated through simulations followed by experiments on a medium voltage DAB hardware implementation of this technique.}, booktitle={Conference Proceedings - IEEE Applied Power Electronics Conference and Exposition - APEC}, author={Tripathi, A. and Madhusoodhanan, S. and Mainali, K. and Vechalapu, K. and Bhattacharya, Subhashish}, year={2016}, pages={886–892} }
 @inproceedings{vechalapu_bhattacharya_brunt_ryu_grider_palmour_2015, title={Comparative evaluation of 15 kV SiC MOSFET and 15 kV SiC IGBT for medium voltage converter under same dv/dt conditions}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84963553261&partnerID=MN8TOARS}, DOI={10.1109/ecce.2015.7309787}, abstractNote={The 15-kV silicon carbide (SiC) MOSFET and 15-kV SiC IGBT are the two state-of-the-art high-voltage SiC devices. These high-voltage SiC devices enable simple two-level converters for a medium-voltage (MV) voltage source converter (VSC) topology compared with the complex three-level neutral point clamped and other multilevel topologies, which, otherwise, is required to realize for MV VSC with silicon devices. This paper characterizes the 15-kV SiC MOSFET module at 10- and 12-kV dc bus for two different configurations of the device under test. This paper also presents endurance test (continuous switching-mode experimental demonstration) of 15-kV SiC MOSFET for 10-kV output voltage for both a bidirectional and unidirectional dc–dc boost converter. Furthermore, this paper presents: 1) the switching loss comparison of 15-kV SiC MOSFET with 15-kV SiC IGBT for the same dv/dt condition; 2) the switching frequency limits of 15-kV SiC MOSFET for a dc–dc boost converter with a phase leg configuration at 10-kV output voltage; and 3) comparative evaluation of 15-kV SiC MOSFET and 15-kV SiC IGBT in a unidirectional dc–dc boost converter for 10 V output voltage.}, booktitle={2015 IEEE Energy Conversion Congress and Exposition, ECCE 2015}, author={Vechalapu, K. and Bhattacharya, Subhashish and Brunt, E. Van and Ryu, S.-H. and Grider, D. and Palmour, J.W.}, year={2015}, pages={927–934} }
 @inproceedings{acharya_vechalapu_bhattacharya_yousefpoor_2015, title={Comparison of DC fault current limiting capability of various modular structured multilevel converters within a multi-terminal DC grid}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84963525471&partnerID=MN8TOARS}, DOI={10.1109/ecce.2015.7310107}, abstractNote={With the development of Modular structured Voltage Source Converters (VSC), Multi-Terminal DC (MTDC) transmission systems have now become a feasible solution to transmit power at high voltage which greatly improves the electric power transmission system. The MTDC grid has lower capital costs and lower losses than an equivalent AC transmission system. Thus for long distance power transmission MTDC grid becomes a very attractive solution. Since the MTDC network is now built based on VSCs, it automatically offers better quality of transmitted power along with more flexibility in power transmission over the conventional current source converters. However, VSC based MTDC transmission systems are vulnerable to DC side fault and expensive DC circuit breakers are required to protect them against DC fault. This paper compares the DC short circuit fault response of different modular multi-level converters (MMC) inside a MTDC system. For the comparison purpose two different kind of MMC topologies have been considered namely, Modular Multi-level Converter (MMC) with High Frequency DC/DC Isolation Stage and MMC with full bridge sub modules. The paper analyzes the fault current limiting capabilities of each of the converters. PSCAD simulation is also done to prove the relevance of the analysis.}, booktitle={2015 ieee energy conversion congress and exposition (ecce)}, author={Acharya, Sayan and Vechalapu, K. and Bhattacharya, S. and Yousefpoor, N.}, year={2015}, pages={3184–3191} }
 @inproceedings{vechalapu_bhattacharya_2015, title={Modular multilevel converter based medium voltage DC amplifier for ship board power system}, booktitle={Ieee international symposium on power electronics for distributed}, author={Vechalapu, K. and Bhattacharya, S.}, year={2015}, pages={419–426} }
 @inproceedings{acharya_azidehak_vechalapu_kashani_chavan_bhattacharya_yousefpoor_2015, title={Operation of hybrid multi-terminal DC system under normal and DC fault operating conditions}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84963585191&partnerID=MN8TOARS}, DOI={10.1109/ecce.2015.7310417}, abstractNote={Recently, multi-terminal DC (MTDC) system has received more attention in the power transmission areas. Development of modular structured power converter topologies has now enabled the power converter technology to attain high voltage high power ratings. Compared to current source converter technology, voltage source converters have several benefits including higher power quality, independent control of active and reactive power etc. This paper focuses on a unique MTDC system consisting of terminals with different converter topologies especially considering the fact that each of the terminals may be manufactured by different vendors. In this particular configuration, the MTDC system consists of four terminals namely two advanced modular multi-level converter with high frequency isolation, one standard modular multi-level converter (MMC) with half bridge sub modules and the fourth terminal is modular DC-DC converter which integrates PV along with a Battery energy storage system with the DC grid directly. This paper presents a system level study of hybrid MTDC System. Also the DC fault contingency case has been explored thoroughly. An algorithm has been proposed to prevent the system damage. All the cases have been demonstrated with the PSCAD simulation results. To show the system practically works in real time, the system is also evaluated in a unique real time platform, consisting of interconnected RTDS and OPAL RT systems.}, booktitle={2015 ieee energy conversion congress and exposition (ecce)}, author={Acharya, Sayan and Azidehak, A. and Vechalapu, K. and Kashani, M. and Chavan, G. and Bhattacharya, S. and Yousefpoor, N.}, year={2015}, pages={5386–5393} }
 @inproceedings{vechalapu_bhattacharya_aleoiza_2015, title={Performance evaluation of series connected 1700V SiC MOSFET devices}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84963541072&partnerID=MN8TOARS}, DOI={10.1109/wipda.2015.7369327}, abstractNote={The low voltage SiC (Silicon carbide) MOSFET (1.2 kV to 1.7 kV) increases the switching frequency limits of a power electronic converter several folds compared to low voltage Si IGBTs. Significant increase in efficiency and power density of voltage source converters can be achieved. However, for medium-voltage high-power converter applications Silicon (Si) devices (4.5 kV and 6.5 kV IGBT) are still dominant. To explore the capability of low voltage SiC devices for medium or high voltage applications, series connection of 1.7 kV/300 A SiC MOSFET modules has been investigated in this paper. A simple RC snubber method has been used for dynamic voltage sharing to offset the turn-off delays due to mismatch on device's characteristics and/or gate signals. Experimental switching characterization with different values of RC snubbers have been carried out to find the optimal RC snubber which gives minimum voltage sharing difference, snubber losses and total semiconductor losses. This paper also intends to show an optimization of the RC snubber for series connection of a limited number of 1.7kV SiC MOSFETs for 6 kV dc bus and for a generalized dc bus voltage.}, booktitle={WiPDA 2015 - 3rd IEEE Workshop on Wide Bandgap Power Devices and Applications}, author={Vechalapu, K. and Bhattacharya, Subhashish and Aleoiza, E.}, year={2015}, pages={184–191} }
 @inproceedings{vechalapu_tripathi_mainali_baliga_bhattacharya_2015, title={Soft switching characterization of 15 kV SiC n-IGBT and performance evaluation for high power converter applications}, url={http://www.scopus.com/inward/record.url?eid=2-s2.0-84963579482&partnerID=MN8TOARS}, DOI={10.1109/ecce.2015.7310246}, abstractNote={The 15 kV SiC IGBT with 2 μm and 5 μm field-stop buffer layer thicknesses are two state of the art HV SiC devices. These 15 kV SiC IGBTs generate high dv/dt with two slopes in punch through and non-punch through regions. To design 15 kV SiC IGBT with reduced dv/dt and single slope dv/dt similar to 10-15 kV SiC MOSFET, requires significantly larger drift epitaxial layer thickness and it increases the size and cost of the 15 kV SiC IGBT. This paper presents the zero voltage switching (ZVS) characteristics of 15 kV SiC N-IGBTs to reduce the dv/dt at switching pole along with reduction in the switching losses and increase in the switching frequency limits with external snubber capacitor. The ZVS characteristics are reported up to 9 kV dc bus voltage at 25°C and 150°C for both IGBTs. This paper also reports continuous mode experimental demonstration of zero voltage switching (ZVS) of 5 μm 15 kV IGBT in a medium voltage half bridge converter up to 7 kV dc bus voltage and calculation of power dissipation per IGBT module and its comparison of switching frequency limits with hard switching of half bridge converter.}, booktitle={2015 IEEE Energy Conversion Congress and Exposition, ECCE 2015}, author={Vechalapu, K. and Tripathi, A. and Mainali, K. and Baliga, B.J. and Bhattacharya, Subhashish}, year={2015}, pages={4151–4158} }