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X-WR-CALDESC:Events for EE
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TZID:Asia/Kolkata
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TZOFFSETFROM:+0530
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DTSTART:20210101T000000
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BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20211207T203000
DTEND;TZID=Asia/Kolkata:20211207T213000
DTSTAMP:20260616T092158
CREATED:20211130T223747Z
LAST-MODIFIED:20211207T044204Z
UID:239361-1638909000-1638912600@ee.iisc.ac.in
SUMMARY:EE PhD Thesis defense of Rejesh N A @3pm
DESCRIPTION:Guide: Prof.. Muthuvel Arigovindan \nTitle: Novel Regularized Image Reconstruction Methods for Sparse Photoacoustic Tomography \nExaminers: Prof. Michael Liebling\, IDIAP Switzerland\, and Prof. Hari Varma\, IIT Bombay \nDate and Time: 7th December 2021 (Tuesday): 3:00 pm – 5:30 pm \nVenue : Online through Microsoft Teams. Click here to join the meeting \nSummary: Among all tissue imaging modalities\, photo-acoustic tomography (PAT)\, has been getting increasing attention in the recent past due to the fact that it has high contrast\, high penetrability\, and has the capability of retrieving high resolution. By using the combination of optical absorption and acoustic wave propagation\, PAT has been able to image tissues at relatively large depths with high resolution compared to purely optical modalities. Upon shining with a laser pulse\, the substance under investigation absorbs optical energy and undergoes thermoelastic expansion; as a result\, the spatial distribution of the concentration of the substance gets translated into the distribution of pressure-rise. This initial pressure rise travels outwards as ultrasound waves which are collected by ultrasound transducers placed at the boundary. From the ultrasound signal measured by the transducers as a function of time\, a PAT reconstruction method recovers an estimate of the initial pressure-rise by solving the associated inverse problem. The inverse problem is however challenging. It is challenging because the image has to be recovered for the entire cross-sectional plane\, whereas the samples of the acoustics pressure are available only from the points lying in the periphery of the imaging specimen where the transducers are located. In this thesis\, we make contributions in two widely used types of reconstructions methods known as the time-reversal method\, and the model-based method. \nWe summarize our contributions in three parts in the following. \nIn the first part\, we develop an improved model-based method. Model-based reconstruction methods in PAT express the measured pressure samples as a linear transformation on the initial pressure-rise and perform a regularized reconstruction. Model-based methods yield superior image quality even in the situation where measured data size is small. We propose a model-based image reconstruction method for PAT involving a novel form of regularization and demonstrate its ability to recover good quality images from datasets of significantly reduced size. The regularization is constructed to suit the physical structure of typical PAT images. We construct it by combining second-order derivatives and intensity into a non-convex form to exploit a structural property of PAT images that we observe: in PAT images\, high intensities and high second-order derivatives are jointly sparse. This regularization is combined with a data fidelity cost\, and the required image is obtained as the minimizer of this cost. As this regularization is non-convex\, the efficiency of the minimization method is crucial in obtaining artefact-free reconstructions. We develop a custom minimization method for efficiently handling this non-convex minimization problem. Further\, as non-convex minimization requires a large number of iterations and the PAT forward model in the data-fidelity term has to be applied in the iterations\, we propose a computational structure for efficient implementation of the forward model with reduced memory requirements. We evaluate the proposed method on both simulated and real measured data sets and compare them with a recent reconstruction method that is based on well-known total variation regularization. \nAppropriate tuning of the regularization weight\, λ\, plays a crucial role in determining the quality of reconstructed images in PAT. To make any regularization method practicable\, we need to have a way to determine the λ from the measured data. Unfortunately\, an appropriately tuned value of the regularization weight varies significantly with the variation in the noise level\, as well as\, with the variation in the high-resolution contents of the image\, in a way that has not been well understood. In the part of the work described above\, we did not address this problem as the focus has been to demonstrate the suitability of the intensity-augmented regularization for PAT image recovery; in the experimental demonstration\, we determined the required regularization weight by using the models that generated data. In the second part of the thesis\, we develop a semi-automatic method for determining the regularization weight from measured data. As a first step\, we introduce a relative smoothness constraint with a parameter; this parameter computationally maps into the actual regularization parameter\, but its tuning does not vary significantly with variation in the noise level\, as well as with the variation in the high-resolution contents of the image. Next\, we construct an algorithm that integrates the task of determining this mapping along with obtaining the reconstruction. Finally\, we demonstrate experimentally that we can run this algorithm with a nominal value of the relative smoothness parameter—a value independent of the noise level and the structure of the underlying image—to obtain good quality reconstructions. We compare the structural similarity (SSIM) scores of reconstructions obtained this way to that of reconstructions in which the regularization weight was determined using the models themselves; we show that the SSIM scores are comparable. This means that\, from a practical point of view\, our work solves the problem of determining the required regularization weight from measured images. \nIn the first two parts\, we assumed that the forward model that measures the signal from the target object be ideal. In particular\, we assumed that the excitation pulse and transducers’ impulse response are Dirac deltas. We focused only on the non-ideality of the transducer configuration\, i.e.\, we handled the case where the transducer locations do not densely sample the detection surface as required by the well-known back-projection method to work. Both excitation pulse and transducer impulse response have a finite width\, and this leads to some distortions in the reconstructed image. In the last part of the thesis\, we propose a pre-processing method for correcting the distortions in the context of using time-reversal methods which are similar to the back-projection method. To this end\, we formulate the broadening of the PA signals as a convolution between the impulse response of the system and the input excitation pulse. A deconvolution method using Tikhonov regularization is proposed to correct the PA signals before applying the time-reversal method. This resulted in improved resolution in the reconstructed images. A two-level deconvolution with the Tikhonov regularization method is also proposed to remove the blurring caused by the finite bandwidth of transducers and by the broad excitation pulses. We evaluate the usefulness of our method using numerical simulations and demonstrate that the reconstructed images from the deconvolved PA signals remain unaffected by the change in pulse widths or pulse shapes\, as well as by the limited bandwidth of the ultrasound detectors. \n—————————— \nALL ARE CORDIALLY INVITED
URL:https://ee.iisc.ac.in/event/ee-phd-thesis-defense-of-rejesh-n-a-3pm/
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BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20211214T203000
DTEND;TZID=Asia/Kolkata:20211214T213000
DTSTAMP:20260616T092158
CREATED:20211116T224237Z
LAST-MODIFIED:20211207T044124Z
UID:239261-1639513800-1639517400@ee.iisc.ac.in
SUMMARY:PhD Colloquium of Asha Radhakrishnan @3pm
DESCRIPTION:Title of the Thesis: Protection of Transmission and Distribution Networks in Presence of Converter – Interfaced Renewable Generators \nAdvisor: Dr. Sarasij Das \nDegree Registered: PhD (Eng.) \nClick here to join the meeting \nAbstract: Power generation from conventional sources like fossil fuels is widely being supplemented by renewable power sources. An increasing degree of penetration of renewable generators is observed in transmission and distribution levels. Power electronic converters are commonly used as interfaces to control the power output of these generators. Fast control and complex dynamics of the power electronic interfaces pose significant challenges to the legacy protection schemes employed in the transmission and distribution networks. This research focuses on addressing the impact of the wide penetration of CIGs on selected protection schemes in transmission and distribution networks. \nDistance protection is one of the most popular methods employed for the primary protection of transmission lines. Mho elements are used extensively in distance protection\, which employs positive sequence memory-polarization (PSMP) technique to give the most reliable performance during close-in faults. The use of memory voltage for polarization leads to the dynamic expansion of the mho circle in distance relays. The dynamic expansion of the mho characteristics increases resistive coverage in the case of synchronous generators. In this research work\, the performance of PSMP mho elements in the presence of CIGs has been studied. Simulations have been performed on the benchmark IEEE-39 bus system with a connected Vdc – Q control-based PV plant. Performances during Zone 1 forward faults and Zone 3 reverse faults have been studied. The results indicate the possibility of a significant reduction in the resistive coverage of the PSMP mho distance element during forward faults and loss of dependability during reverse faults. A novel solution to the observed problem has been proposed and validated using PSCAD simulations on the IEEE 39-bus system. The proposed solution is found to effectively achieve a predictable performance of PSMP mho relays in the presence of PV generators as well as synchronous generators. \nBack-up protection of transmission lines is important to be in place to ensure dependable protection during failure of primary protection. Breaker failure protection (BFP) is an important backup protection. It is employed to take appropriate action to clear a fault when the breaker that is normally expected to clear the fault fails to do so for any reason. Fault current contribution of CIGs is usually comparable with load currents. Low fault current contribution by utility-scale CIGs may lead to significant loss of security of BFP because of the existing practice of using lower setting for 50BF overcurrent element. This research work proposes a voltage-dependent adaptive setting of 50BF element to enhance the security of BFP schemes while maintaining dependability. Use of voltage helps in differentiating loads from fault situations. In traditional power systems\, CT subsidence current is known to delay the reset of BFP schemes. The impact of low fault contribution by CIGs on the reset time of BFP has been studied. Mathematical expression for CT subsidence current\, which influences the reset time\, has been derived. It is observed that the BFP reset may not be delayed if the fault current seen by the breaker is low due to the presence of CIG. The performance of the proposed 50BF setting and the findings on the subsidence current are supported using PSCAD simulations. \nThe Rate of Change of Frequency (RoCoF) relays are employed to arrest frequency collapse of a grid in the event of sudden loss of major generation. With large-scale CIGs replacing the synchronous generators\, the primary frequency response of the system is often affected due to the decrease in the system inertia. The rate of change of frequency at the inception of an event is observed to increase for a system with high penetration of CIGs. The settings of RoCoF relays are therefore required to be revised to account for the faster dynamics of CIGs. With varying degree of CIG penetrations\, the settings may change further. This work proposes a new method to detect the system changes by considering voltage as the parameter. The proposed method has been validated using PSCAD simulations performed on the IEEE39-bus system. Different degrees of CIG penetrations have been considered to test the performance of the proposed method. \nPenetration of Distributed Generations (DGs) has made traditional distribution protection schemes mostly ineffective. Sophisticated protection schemes cannot be implemented using fuses\, reclosers and Miniature Circuit Breakers (MCBs). Economics limits the use of protective relays in distribution systems. Voltage based protection is often not economical for distribution systems. Smart Meters (SMs) are available at various load points in a distribution system. SMs are equipped with measuring\, calculation\, and communication capabilities. This work proposes the utilization of SMs in distribution system protection. The possible applications of SMs in high impedance faults (HIF)\, overcurrent\, reverse power\, series arcing\, and under-voltage protection of distribution systems are identified in this work. Voltage-based protection can also be implemented using SMs. This work also proposes a voltage-based HIF location method. The fault signature of HIF is significant at the SMs which are nearer to the fault. The proposed method uses the SMs to compute an index to capture the fault signature. The HIF is then located in a zone defined by SMs adjacent to the SM with the highest index. The performance of the proposed method has been evaluated considering electric arc furnaces\, DGs and power electronics-interfaced loads. The effectiveness of the proposed SM-based protection has been demonstrated by simulating a European low voltage test feeder comprising of 906 buses in PSCAD. The proposed algorithm has also been implemented on a commercial smart energy meter to demonstrate its feasibility. \nALL ARE CORDIALLY INVITED \n 
URL:https://ee.iisc.ac.in/event/phd-colloquium-ee-by-asha-radhakrishnan/
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BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20211216T210000
DTEND;TZID=Asia/Kolkata:20211216T223000
DTSTAMP:20260616T092158
CREATED:20211207T044035Z
LAST-MODIFIED:20211207T044405Z
UID:239398-1639688400-1639693800@ee.iisc.ac.in
SUMMARY:MTech(Research) Colloquium of  Paawan Kirankumar Dubal @3.30pm
DESCRIPTION:Guide: Dr. Sarasij Das \nTitle: Cyber Attack Resilient Breaker Failure Protection Scheme Using Wide Area measurements \nName of the Student: Paawan Kirankumar Dubal \nDate and Time: 16th December\, 2021\, 3:30 PM \nclick here for  the Meeting Link \nAbstract: Breaker Failure Protection (BFP) is a backup protection that comes into play when a circuit breaker fails to isolate the fault. If the circuit breaker fails to clear the fault\, the BFP scheme commands other required breakers to isolate the fault. BFP schemes are usually incorporated in microprocessor-based digital relays. Commonly employed BFP schemes use overcurrent element (50BF) and Breaker Failure Initiation (BFI) signals as inputs. The BFI signal is issued to the BFP relays from other digital relays. Line current sensed via current transformer is fed to the BFP relay for the overcurrent element (50BF). When both 50BF and BFI are high\, it waits for a specified time for the primary protection to operate. The 50BF element is usually set much lower than the rated load currents. So\, it will be high during the normal loading conditions. A cyber-attack can be launched by issuing false BFI or blocking a legitimate BFI signal to the BFP relay. Operation of BFP scheme usually leads to disconnection of a larger amount of loads. As a result\, mal-operation of BFP schemes can cause major disturbances in power systems. There is a need to make the BFP schemes resilient to cyber-attacks for reliable operation of power systems. Currently\, there is a lack of literature on the cyber-attack resilient BFP schemes. \nHence\, this thesis proposes a Wide-Area Measurement-Based Cyber-Resilient Breaker Failure Protection Scheme. The scope of the work is to develop an algorithm that will ascertain if the BFI received by the BFP relay is genuine. Blocking a legitimate BFI will cause the backup protection to operate and clear the fault. The proposition assumes that the BFP relay is not compromised in any manner. However\, a fake BFI can be issued by other digital relays\, which may cause unwanted BFP operations. In the proposed algorithm\, when the BFI is received. The BFP relay will communicate the receipt of BFI to the Phasor Data Concentrator (PDC). The proposed algorithm will run at the PDC\, which has access to the time-stamped measurements of the adjacent substations and the substation that triggered the algorithm. The decision of the proposed algorithm is communicated back to the BFP relay\, which will allow the tripping if the BFI is genuine. Hence\, we also propose modifications in the BF scheme in the BFP relay to incorporate the algorithm’s decision in issuing the final trip. The proposal running at PDC is a two-layer algorithm. The first layer randomly samples the bus voltages at the adjacent substations considering different groups of digital relays. The relay which has issued the BFI may be compromised. It makes relays of the same make and family more susceptible to a cyber-attack exploiting the same vulnerabilities. Hence we propose grouping of relays by their make and relay families. The first layer is meant to determine if there is a fault in the vicinity of the BFP relay that issued the trigger. The second layer provides discrimination between fault and cyber-attack by measuring the impedance observed at the two ends of the perceived-faulted line. Since the proposed solution is computationally lightweight\, it adheres to the timing requirement of the BFP. The proposition requires healthy communication between the PMUs and the PDC. Nevertheless\, the proposed method is fail-safe. It will resort to the conventional BFP scheme in case of loss of communication with the PDC. The proposed solution mitigates n number of cyber-attacks in a no-fault scenario. Additionally\, the proposed solution can detect one cyber-attack if the attacker times the cyber-attack during a fault condition. PSCAD simulations were performed to validate the proposition on IEEE 118 bus system. Furthermore\, the hardware was developed emulating the PMU-PDC communication as per IEEE C37.118-2 standard\, and the execution time of the proposal was verified to ensure adherence to the timing requirement of the BFP. \nALL ARE CORDIALLY INVITED
URL:https://ee.iisc.ac.in/event/mtechresearch-colloquium-of-paawan-kirankumar-dubal-3-30pm/
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BEGIN:VEVENT
DTSTART;TZID=Asia/Kolkata:20211217T203000
DTEND;TZID=Asia/Kolkata:20211217T220000
DTSTAMP:20260616T092158
CREATED:20211216T020558Z
LAST-MODIFIED:20211216T020726Z
UID:239421-1639773000-1639778400@ee.iisc.ac.in
SUMMARY:PhD Thesis Colloquium of Kiran Kumar Challa @ 3pm
DESCRIPTION:Title: Estimation of Synchronous Generator Parameters from Digital Relay Records and Development of an Experimental Testbed for Validation \nFaculty Adviser: Dr. Gurunath Gurrala. \nDate : 17th December 2021 \nTime: 3pm – 4.30pm \nMode: Hybrid mode\, both Teams and Physical \nVenue: MMCR\, 1st floor C-wing\, EE Department\, IISc \nTeams Link: Click here to join the meeting. \nAbstract: The development of dynamic power system components models became increasingly important in the modern grids dominated by high penetration of renewables because of the increased dependency of planning and operational decisions on dynamic simulation studies. The parameters of synchronous machines and associated control models play significant role in the overall model of the grid\, which need to be updated regularly by the utilities. So\, the parameters of the power plants are calibrated/estimated either using off-line testing or online measurements from phasor measurement units (PMU) or digital fault recorders (DFR). Development of individual generator models is feasible only if the PMU/DFR data is available for each generator in a power plant. Otherwise\, they can provide only aggregate model of a generating plant as PMU/DFRs are usually placed in substations. Digital protective relay (DPR) records are available for individual generators in any generating plant. This thesis explores the possibilities of utilizing DPR records of individual generators for parameter estimation. About 200 relay records have been collected from a hydro plant and a thermal plant in Karnataka. It is found that most of the records contain at the most 3 seconds data. Existing methods of parameter estimation using PMU/DFR data failed to work with the short duration records. There is no prior work reported in the literature which uses short relay records for parameter estimation of the synchronous generators. Constrained iterated unscented Kalman filter (CIUKF) and enhanced scattered search (eSS) algorithms are proposed for the parameter estimation using DPR records in this thesis. The parameters of a turbo alternator and its excitation system (210 MW) are estimated from the relay records collected using the proposed algorithms and the results are found be accurate. This is a first of its kind effort in the literature to the best of our knowledge. It is also found that the relay records should contain pre-fault data\, during fault data and some post-fault data for accurate estimation. However\, from the collected records only a small percentage of the records are found to be useful. To generate realistic data in the laboratory an experimental test bed development\, replicating the field implementation aspects of the digital relays\, is proposed in this thesis. A realistic scaled-down generalized substation model for translational research in smart grids is developed\, which can be configured to operate in 7 widely used substation bus bar schemes with prevalent current transformer (CT) configurations. All the potential transformers (PT) and CT measurements\, circuit breaker (CB)\, isolator and earth switch status signals are made available to configure any protection strategy like bus-bar protection\, unit protection schemes\, etc. precisely the same way they get implemented in the field. A systematic procedure for the development of an experimental scaled-down frequency-dependent transmission line model of a 230 kV transmission line is proposed. A lumped parameter frequency dependent transmission line model using modal transformation is derived for a 230 kV transmission line and scaled-down to 220 V. Clarke and inverse Clarke transformations are implemented using specially designed 1-phase transformers. The inductances of the scaled-down model are realized using amorphous cores. A new algorithm is proposed to fit a reduced-order R-L equivalent circuit to the frequency response of the modal impedances of the transmission lines. A close enough fitting is achieved with lesser number of passive elements using the proposed method compared to the widely used vector fitting algorithm. This kind of physical realization of a frequency dependent power transmission line model in the laboratory is first of its kind effort in the literature to the best of our knowledge. \nNote: Know how generated from the implementation of the generalized substation panels and transmission line models has been licensed to MCore Technologies Pvt Ltd\, Bangalore for commercialization. \nAcknowledgements: This work is supported by Fund for Improvement of Science and Technology (FIST) program\, DST\, India\, No.SR/FST/ETII-063/2015 (C) and (G) under the project “Smart Energy Systems Infrastructure – Hybrid Test Bed”. Acknowledge partial funding support from Robert Bosch Centre for Cyber Physical Systems (RBCCPS)\, IISc. Also acknowledge the Tata Trust Travel Grant.
URL:https://ee.iisc.ac.in/event/phd-thesis-colloquium-of-kiran-kumar-challa-3pm/
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DTSTART;TZID=Asia/Kolkata:20211223T153000
DTEND;TZID=Asia/Kolkata:20211223T163000
DTSTAMP:20260616T092158
CREATED:20211221T011203Z
LAST-MODIFIED:20211221T011411Z
UID:239439-1640273400-1640277000@ee.iisc.ac.in
SUMMARY:PhD Thesis Colloquium of Shamibrota Kishore Roy
DESCRIPTION:Title: Characterization and Modelling of Switching Dynamics of SiC MOSFETs \nName of the Advisor: Dr Kaushik Basu \nDate and Time: 23rd December 2021\, 10:00 AM \nPlace: Offline (MMCR EE\,) online: Meeting Link: Click here to join the meeting \nAbstract: Silicon Carbide (SiC) MOSFET is a wide bandgap (WBG) power device commercially available in the voltage range of 600-1700V. With superior switching\, conduction\, and thermal performance\, it is in close competition with the state-of-the-art Si IGBTs in this voltage range. \nIn power electronic converters\, semiconductor devices operate as switches. They can be turned on or off using a control signal. Unlike ideal switches\, practical devices require a finite amount of time to transit between on and off states. This is termed as switching transient. Non-zero finite product of voltage and current during switching transient results in switching loss. Characterization and modelling of switching dynamics help gain insight into the switching process and estimate switching loss. Estimated loss can be used to determine switching frequency and selection of power devices. Also\, switching dynamics is strongly impacted by the device and circuit parasitics. Insight into the switching process helps in the proper design of gate driver and power circuit layout. \nThe switching transient of SiC MOSFET is fast compared to its Si counterpart\, resulting in reduced switching loss. However\, it excites device and circuit parasitics that may lead to prolonged oscillations\, spurious turn on\, high device stress\, EMI-related issues\, Etc. The nonlinearity of the device characteristics and impact of circuit parasitics makes the switching transient of SiC MOSFET more involved than its Si counterpart. So\, the characterization and modelling of switching dynamics of SiC MOSFET are essential. \nExperimental\, simulation and analytical approaches are used to study the switching dynamics and estimate switching loss. The experimental approach is inaccurate\, requires expensive measurement set-ups\, and is not suitable for the early stages of power converter design. The behavioural modelling approach is a widely used simulation-based approach (i.e.\, Spice simulation) where the circuit-based model of the device is used along with lumped parameter model of the external circuit. These models are simple and can capture the switching transient with sufficient accuracy. However\, it does not provide insight into the switching process\, and applying it for a large set of devices and operating conditions will be time-consuming. The analytical model belongs to another class of switching transient models. It is based on the simplified approximate solution of a set of coupled non-linear differential equations obtained from the behavioral model and results in analytical closed-form solutions or reduced order coupled non-linear equations. This model is computationally efficient and can be implemented easily in freely available programming platforms such as C or Python. Also\, the parameters required for analytical models can be obtained from the device datasheet. This modelling approach is beneficial at the early stages of the converter design when switching loss and junction temperature need to be evaluated over several operating points for many available devices from different manufacturers. This work focuses on developing analytical models. \nThe first part of the work proposes an analytical model to capture the switching dynamics (turn on and off) of SiC MOSFET. In the existing literature\, simplified modelling of channel current and device capacitances were used\, resulting in underestimating switching transition time and loss. On the contrary\, the proposed approach considers the detailed non-linear model of channel current and device capacitances along with circuit parasitics. It accurately estimates transition time\, switching loss\, (dv/dt)\, (di/dt)\, and transient over-voltage. \nIn soft switched converters (i.e.\, DAB)\, hard turn on is avoided by the converter operation\, and the switching loss is solely dictated by the turn off loss. The addition of external capacitance across the device prolongs the voltage rise period and reduces overlap between voltage and current during turn off transient. This is termed as zero voltage switching (ZVS). However\, the selection of external capacitance is not straightforward. A large external capacitance reduces switching loss\, (dv/dt)\, (di/dt)\, and transient over-voltage but may also result in higher dead-time loss and reduced switching frequency. Also\, this may lead to partial soft switching for light load conditions if the dead-time is not sufficient. In this work\, an analytical model to capture capacitor-assisted turn-off switching transient is also presented where the detailed non-linear modelling of the SiC MOSFET is used. This leads to a better estimation of switching transition time\, actual loss\, (dv/dt)\, (di/dt)\, and transient over voltage. Also\, a step-by-step design procedure of the optimal external snubber capacitor was proposed. It ensures the soft-switching condition is satisfied\, and the maximum (dv/dt) rate is within a predefined limit for a specified DC bus voltage and range of load currents. This procedure also helps in the selection of proper dead-time to avoid partial soft-switching conditions. \nDouble pulse test (DPT) based experimental measurement is used to first validate the behavioural model. Then\, the behavioural model is used to verify the correctness of the proposed analytical models. This indirect verification approach is necessary as it is not possible to measure the actual switching loss directly from the experimental measurements. Two 1.2-kV SiC MOSFETs of different current ratings are used for validation. It has been observed that there can be a significant difference between the experimentally measured switching loss and actual loss\, and the difference is more prominent for low external gate resistances. Also\, the turn off loss of SiC MOSFET is small compared to the turn-on loss. \nFast switching transient of SiC MOSFET is significantly impacted by circuit parasitics. Circuit parasitic inductances are dependent on both device package (device lead\, wire bond etc.) and circuit layout (PCB layout)\, whereas circuit parasitic capacitances are contributed solely by the circuit layout. Proposed switching transient models require circuit parasitics as input\, and the values are not usually available in the device datasheet. Measurement is the only way to accurately estimate some device package-dependent circuit parasitics when the internal package geometry is unknown. In this context\, a set of simple measurement techniques are proposed to determine important circuit parasitics necessary for switching dynamics study. The accuracy of the proposed technique is verified through behavioural simulation\, and experimental results of the hard turn off and capacitor assisted soft turn off dynamics of SiC MOSFET over a range of operating conditions for two 1.2-kV discrete SiC MOSFET of different current ratings and two different PCB layouts. Measured circuit parasitic when used in switching transient model\, correctly predicted both hard turn-off and capacitor assisted soft turn off switching dynamics over a wide range of operating conditions. \nAn interactive software based on the proposed analytical model is also developed in Python environment. The developed software takes device parameters and circuit parasitics as input and estimates transition time\, switching loss\, (dv/dt)\, (di/dt) and transient over-voltage as a function of load current. \nALL ARE CORDIALLY INVITED
URL:https://ee.iisc.ac.in/event/phd-thesis-colloquium-of-shamibrota-kishore-roy/
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