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EPE 2021 - Dialogue session - Devices, Components, Packaging and System Integration
You are here: EPE Documents > 01 - EPE & EPE ECCE Conference Proceedings > EPE 2021 ECCE Europe - Conference > EPE 2021 - Topic 01: Devices, Packaging and System Integration > EPE 2021 - Dialogue session - Devices, Components, Packaging and System Integration
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	A GaN-Based Monolithic Full-Bridge Class D Audio Amplifier   By Federica CAMMARATA	[View]   [Download]
Abstract: This paper presents the analysis and the experimental validation of a high-frequency Class D audio amplifier. The peculiarity is the use of a GaN-based monolithic full-bridge. On the one side, GaN technology allows achieving very high operating frequency with low power losses. On the other side, the monolithic nature of the power converter enables a strong reduction of device switching losses and electrical stresses. Moreover, by combing the GaN technology with the monolithic nature of the power converter in a truly innovative package, a notable improvement of the total harmonic distortion (THD) and of the sound quality can be obtained. The developed application is characterized by a 2.3MHz operating frequency.
	A reverse-conducting IGBT enabling high switching frequency up to 60 kHz for PFCs in home appliances   By Jaeeul YEON	[View]   [Download]
Abstract: The latest reverse-conducting (RC) IGBT, the TRENCHSTOPTM 5, WR6 IGBT, combined with a separate silicon carbide (SiC) boost diode, significantly improves the performance of the high-power continuous conduction mode (CCM) power factor correction (PFC) circuit. It increases switching frequency and minimizes the inductor size to be mounted on the printed circuit boards (PCB). This paper validates the performance of the WR6 IGBT compared to an equivalent CoolMOS P7 MOSFET at the switching frequency of 60 kHz by means of a loss analysis and experimental results using a 2.5kW CCM PFC setup.
	Accuracy Study of Calorimetric Switching Loss Energy Measurements for Wide Bandgap Power Transistors   By Julian WEIMER	[View]   [Download]
Abstract: Despite soft-switching topologies and modern wide bandgap power semiconductors, switching loss energy is still significant in power electronic application but too small for characterization with electrical measurements. In contrast calorimetric measurements of the soft-switching energy of a commutation cell have been successfully demonstrated for different power classes and semiconductor technologies. In particular, the transient calorimetric measurement method calibrated by thermal impedance ($Z\_\mathrm{th}$-calibrated) promises an extremely fast and non-invasive loss characterization in a wide power range without modification of the half-bridge. This enables automated determination of the switching behavior and losses over the entire operating point range of different switching voltages and switching currents in a reasonable time frame compared to other thermal measurement methods. Furthermore, it promises to greatly reduce the requirements on the measurement setup in terms of thermal insulation and the integration of temperature sensors.Purpose of this work is to investigate the accuracy of $Z\_\mathrm{th}$-calibrated calorimetric measurements and to estimate the influence of measurement duration, temperature sensing and thermal insulation, which so far prevent simple application-oriented characterization. Therefore, a gallium nitride (GaN) high-electron-mobility transistor (HEMT) half-bridge is used to derive the loss measurement accuracy of different temperature sensors and the modeling of junction temperature dependend on resistance by comparing it to conduction losses that are electrically easy to determine. In addition, the worst-case accuracy of the switching energy calculation based on multiple power dissipation measurements with different switching frequencies is presented.
	Additive Manufacturing of 10 W Power Converter with High Power Density   By Daniel DELL	[View]   [Download]
Abstract: Achieving high power density for power electronics applications such as flyback AC/DC power con- verters requires three-dimensional integration of active and passive components, especially when using industry standard parts. 3D printing provides the flexibility to fabricate various plastic carriers from dif- ferent materials without the need for expensive tooling, while still enabling complex structures for elec- trically, thermally and mechanically optimized setups. This paper presents a 3D integrated 10 W AC/DC flyback converter using additive manufacturing compared to the conventional planar PCB approach. The additive manufactured plastic structure combines the qualities of a heat sink, isolator and mechanical linkage. Furthermore, passive components are optimized in volume through rigorous selection. Ceramic capacitors are exclusively used, because the cuboid shape is perfectly suited for a high degree of 3D integration while parasitic losses are reduced in comparison to electrolytic capacitors. For efficient com- ponent placement and sufficient power dissipation budget, the converter housing is cube shaped with structured surface. All active and passive components are completely enclosed in the plastic additive manufactured structure, which improves the thermal connection. To avoid internal and surface hotspots, the filament selection and positioning of the heat sources is optimized by means of thermal 3D-FEM simulation. The 3D integration of the components results in 252 \% higher power density in comparison to the conventional planar designs, maintaining the same functionality with identical commutation cell and magnetics. The comparative measurements are performed in DC/DC converter operation at 325 V input and 12 V output up to an output power of 10 W.
	An Analytical Switching Loss Model for a SiC MOSFET and Schottky Diode Half-Bridge Based on Nonlinear Differential Equations   By Anliang HU	[View]   [Download]
Abstract: An accurate analytical switching loss model for a SiC MOSFET and Schottky diode half-bridge for a wide operating range is proposed in this paper, which is based on nonlinear differential circuit equations including parasitics. In the model, nonlinear device characteristics are used, including the dynamic gate-drain capacitance and the transfer characteristics measured under real switching conditions. With the proposed model, the accuracy improvement by using measured characteristics instead of device data sheet information is analyzed. In addition, the impact of making different common assumptions/simplifications on the accuracy of switching loss models is evaluated.
	Analysis of dv/dt Discrepancy between High Power SiC-MOSFET Inverter Output and its Semiconductors   By Felix KAYSER	[View]   [Download]
Abstract: High dv/dt of fast switching power semiconductors lead to high stress for the motor insulation. Thispaper presents the significant differences between the dv/dt at the power semiconductor and the inverterterminals and how this is influenced by inductive coupling of inverter phases.
	Analytical Triple-2D Leakage Inductance Model of Cone Winding Matrix Transformers   By Richard SCHLESINGER	[View]   [Download]
Abstract: The transformer leakage inductance is one of the limiting factors for pulse shape quality in high voltage pulsed power (HVPP) applications such as cancer treatment, particle accelerators, and free electron lasers. Cone winding matrix (CWM) transformers are commonly used in HVPP applications as they offer low leakage inductance, low parasitic capacitance, high power density, and high insulation distance. This paper proposes an analytical Triple-2D leakage inductance model for CWM transformers. The model is based on a 2D model applicable to tilted cone windings which is derived by analytically integrating the magnetic potential. The Triple-2D modelling concept enables high accuracy and versatility. The model is verified with 2D FEM simulations and measurements on an existing pulse transformer for the compact linear collider at CERN. The analytical model is not only accurate and generally applicable but also rapidly executable enabling its time-efficient integration in optimisations.
	Benefits of implementing a duty-ratio controlled parallel-resonant converter with SiC MOSFETs instead of Si IGBTs.   By Evangelos LIAKOS	[View]   [Download]
Abstract: In this paper, the operation of a parallel resonant converter that exploits the parasitic components of itstransformer is described briefly. Measurements from a high power DC pulsed generator with Si IGBTsare obtained. Finally, the experimentally calculated losses of the Si IGBTs are compared with SiCMOSFETs' losses using simulations of the system.
	Comparing Switching and Conduction Losses of Uni- and Bidirectional SiC Semiconductor Switches for AC Applications   By Daniel GOLDMANN	[View]   [Download]
Abstract: The presented research elaborates on the increase in conduction and switching losses when combining two regular SiC MosFETs to one bidirectional switch. The conduction losses are expected to double due to two semiconductors conducting the current while the switching losses should increase since the loop inductance is increased. Both effects are directly investigated through extensive double pulse tests and conduction loss measurements. The measured conduction losses are significantly lower than expected while no increase in switching losses can be measured. These directly measured losses are further verified through efficiency measurements with a 15 kW dc-dc converter prototype.
	Comparison of Reverse Conducting IGBT Concepts regarding Reverse-Recovery Behavior and Gate Drive Requirements   By Daniel LEXOW	[View]   [Download]
Abstract: Reverse Conducting IGBT use n-shorts at the backside emitter to allow conduction of the body diode of the MOS structure. The p-well of the MOS cell acts as an anode of the diode. The anode efficiency strongly depends on the gate-emitter voltage. There are different concepts on how to deal with this behavior. This paper describes the influence on the static and dynamic diode behavior and the conse-quences for the gate drive.
	Controllable inductance as actuator in power electronics   By Peter ZACHARIAS	[View]   [Download]
Abstract: In this paper controllable devices with nanocrystalline and amorphous materials and ferrites arepresented and compared. The materials made of amorphous and nanocrystalline materials arecharacterized by very low coercivity and a continuously decreasing permeability. Both are veryadvantageous characteristics for the realization of controllable inductive components.
	Current Sharing of Parallel SiC MOSFETs under Short Circuit Conditions   By Ruizhu WU	[View]   [Download]
Abstract: Device-to-device parametric variations (e.g. threshold voltage VTH, gate resistance RG and junction temperature TJ) can cause variations in the short-circuit currents conducted through parallel-connected devices. In this paper, the impact of variations in VTH, RG and TJ on current sharing under short-circuits is investigated using measurements and electrothermal modelling. The results show that VTH is the most critical parameter affecting short-circuit current sharing and directly impacts the peak short circuit current. Variations in gate resistance do not impact the short circuit current sharing unless the variation is over 400\% thereby indicating catastrophic failure of the gate wirebond. Variation in the initial junction temperature is also not as critical as variations in VTH since the higher temperature device takes less short circuit current. Electrothermal simulations of parallel connected SiC MOSFETs have been developed to analyze how VTH mismatch impacts short circuit current sharing. These simulations allow for the investigation of the impact of VTH mismatch on the electrothermal stresses of the parallel connected MOSFETs.
	Design and Analysis of a Fully-integrated Planar Transformer for LCLC Resonant Converters   By Sajad ANSARI	[View]   [Download]
Abstract: The isolated LCLC resonant converter needs five discrete passive components including two capacitors, two inductors and a transformer. In this paper, to cut down the number of components of this converter, a new design for a high-frequency transformer is proposed which integrates all the five magnetic and capacitive components in only a single magnetic device. The series capacitor and inductor are integrated into the primary winding and the parallel capacitor and inductor are integrated into the secondary winding. The design guideline for this transformer is presented in detail and theoretical analysis is confirmed by simulation results.
	Design Considerations for High-Voltage High-Current Bi-Directional DC Solid-State Circuit Breaker (SSCB) for Aerospace Applications   By Asad FAYYAZ	[View]   [Download]
Abstract: Design of a high-voltage and high-current solid-state circuit breaker (SSCB) for aerospace applications is highly challenging, as the overall system should comply with the most stringent operating environment. In addition, the implemented power semiconductor devices within the SSCB would require excellent thermal performance and efficiency with minimised conduction losses as they always operate during on-state and only break current when there is a fault. The newer generation of the more electric aircraft architecture has a proposed DC link voltage of 2.4 kV (+/- 1.2 kV) which is much higher than the presently used DC link voltage of 540 V (+/- 270 V). The proposed DC SSCB would be rated at 2.4 kV with a nominal current rating of 100 A and would be used for protection and controllability to protect the aircraft's DC grid transmission network. A brief overview of the different elements of a DC SSCB have been discussed here followed by a discussion about the different viable bi-directional SSCB topology configurations. The thermal simulations were carried out in PLECs, which provide the conduction losses and junction temperature dynamics for different switch (Si devices and SiC MOSFETs) types and topologies. Moreover, different figures of merit such as conduction losses, semiconductor weight, and power density are also discussed.
	Design Methodology for Ultra-Compact Rogowski Coils for Current Sensing in Low-Voltage High-Current GaN Based DC/DC-Converters   By Dominik KOCH	[View]   [Download]
Abstract: This paper presents a design methodology, verified by measurements, of a differential Rogowski coilbased compact, high bandwidth (sup. 500MHz) PCB embedded current sensor for minimal invasive sensing (insertion inductance ˜ 200pH) of transistor and phase currents in 48V mild-hybrid Gallium Nitride based DC/DC-converters with paralleled transistors for high output currents. Two different sensor concepts with and without a planar shield are described and investigated. More than 30 designs with different winding number, structure and pitch are analyzed in 3D-finite element simulations. Finally, a standalone Rogowski-coil sensor for transistor current and a combination of a magnetoresistance sensor and a Rogowski-coil for phase output current measurements are presented.
	Design Space Optimization of a SiC Drive Inverter with an Integrated All-Pole Sine Filter   By Sascha LANGFERMANN	[View]   [Download]
Abstract: The aim of this paper is to minimize an all-pole sine filter by increasing the switching frequency so that it can be integrated into a SiC drive inverter. For this purpose, theoretical considerations of the influence of the switching frequencies on the size and losses of the inductor, the capacitor, the semiconductor, and the heat sink size for the semiconductors were carried out. A parameter study of a filter concept as a function of the switching frequency has been discussed. Detailed analysis of three inductors is made, which consist of various simulation models.Two prototypes of all-pole sine filters are built for a switching frequency of 128 kHz. These two prototypes were operated in a drive system consisting of a SiC drive inverter and motor to measure and evaluate the filter effect and thermals of the filters. The filter behavior in the event of overload is also discussed.
	Dynamic Thermal Design of an Active Power Cycling Test Bench for SiC MOSFETs   By Maximilian NITZSCHE	[View]   [Download]
Abstract: This paper presents an active power cycling approach whereby the inputs and outputs of two three-phase inverters are coupled in order to achieve circular energy flow. Focus is put on the thermal design of the test setup which concentrates on achieving short thermal cycles and high temperature dynamic for accelerated lifetime tests of SiC MOSFETs. These goals are achieved by the application of custom 3D-printed aluminum heat sinks and by using non-constant flow of the cooling medium.
	Enhanced thermal management of a 48 V powertrain for electric motorbikes   By Carlos MIGUEL ESPINAR	[View]   [Download]
Abstract: This paper presents a predictive derating method whose purpose is to improve the thermal management of a low-voltage traction inverter for electric motorbikes. The proposed strategy achieves better power extraction during the heating of the power converter than other classic static alternatives such as linear, convex or concave approaches. The results are validated through simulations and experimental results showing that the predictive proposal achieves up to 3.4\% of jerk capability when compared to other classic options.
	Experimental Evaluation of an Enhanced GaN-Based Non-Symmetric Switching Leg Integrated Module for Synchronous Buck Converter Applications   By Salvatore MUSUMECI	[View]   [Download]
Abstract: The paper deals with an improved low-voltage monolithic power stage switching leg based on GaN FET devices applied to a synchronous buck converter for not isolated auxiliary power supply in 48V to 12V regulation voltage application. The switching leg module is designed with two GaN FETcomponents with different electrical parameters characteristics in order to optimize the power losses and the switching performance in a 500kHz switching frequency synchronous step-down converter. In the paper the asymmetric switching leg is described and experimentally evaluated. Furthermore, a comparison with a state of art GaN FETs integrated switching leg is carried out in a synchronous stepdown converter suitable to use in a volume reduced auxiliary power supply oriented to 48V regulator for automotive application.
	Extension on ASM HEMT Model with Trapping Effects in GaN Power Devices   By Mathias WEISER	[View]   [Download]
Abstract: We present a model to simulate the dynamic drain source resistance of GaN-based HEMTs in circuit simulators. Instead of discrete RC-subcircuits for trap charging and discharging processes, the proposed model uses a distributed RC network to approximate a Gaussian distribution of capture and release time constants to decrease the parameter count and increase accuracy. We have implemented the model into the ASM-HEMT standard compact model and applied it to a commercial 100 V GaN-on-Si HEMT. The model considers the drain source resistance evolution over many magnitudes in time. It can be used to predict additional trapping-induced losses in switched-mode power supplies.
	Formula Evaluation and Voltage Distribution of Planar Transformers Using Rectangular Windings   By Theofilos PAPADOPOULOS	[View]   [Download]
Abstract: This study investigates the inductance formulas for square-shaped planar windings and suggests modifications so they can apply to rectangle-shaped windings, with simple yet accurate approximations. Furthermore, it explores the region of high-power, high-frequency planar transformers, introducing an algorithm which estimates the applied voltage per turn. This effort can lead to design optimization, by minimizing the spacing between traces, thus increasing the inductance over used area. A comparison of theoretical, simulation and experimental results is carried out to evaluate three well-established formulas under the proposed modification. The voltage distribution algorithm is also verified using the same methods.
	Mission Profile-Based Electro-Thermal Model of Robotic Manufacturing Application   By Oskars BORMANIS	[View]   [Download]
Abstract: This paper presents a developed IGBT junction temperature estimation model of a 6-axis industrial robot drive inverter. The interface between the robot program code and the thermal model is introduced. The main novelty is the evaluation of thermal stress as a result of the robot movement analysis. Future development and application suggestions are discussed.
	Modelling a Modified Equivalent Circuit of a Single-Layer, solenoidal Inductor at High Frequency   By Rasha SAEED	[View]   [Download]
Abstract: In the design of high-power density converters, increasing the switching frequency is one of the mainfactors to enable the reduction in the required value and size of the passive components. The switchingfrequency can reach a few MHz in the case of Gallium Nitride devices. At such a high frequency a slightvariation in the capacitances and inductances in the converter circuit, can have a considerable effect onits switching behaviour. Therefore, a 3D design of stray elements, such as equivalent series inductanceof capacitors and equivalent parallel capacitance of inductors is required to control these effects andimprove the converter performance. Also, having both active and passive components integrated withthe whole converter will allow us to better control the effects of the parasitic elements and achieve amore optimal switching behaviour.In this paper, a Modified Equivalent Circuit (MEC) from the Classic Equivalent Circuit (CEC) has beenproposed and is based on physical properties of single-layer solenoid inductor along with a suggestedpath of the energy transfer between the two adjacent turns of the inductor. Both inductance andcapacitance matrices are obtained using magneto-static and electro-static finite element simulations(using MAXWELL). The results of these FEM simulations coupled with the proposed equivalentelectric circuit is used to predict the frequency behaviour of the component. The model is validatedexperimentally using an experimental inductor demonstrator.
	New Method for Calculating HF-Losses in Litz Wire caused by 2D Magnetic Fields   By Qingchao MENG	[View]   [Download]
Abstract: A new method based on approximating 2D curved field lines by straight field lines with a piece-wiselinear amplitude for calculating the HF-losses in Litz wire caused by a 2D magnetic field in the corewindow is presented in this paper. The error of the proposed method is less than 5\% for the consideredtransformer cases which is much smaller than the typical error of known 1D-field winding loss models(10\%__30\%). The computation time of the proposed method is in the range of a few milliseconds andthus suitable for converter optimization routines.
	Optimal Design of a Transformer-based Solid-State Pulse Modulator with a Damping Network for Ultra-Fast Rise Times   By Spyridon STATHIS	[View]   [Download]
Abstract: This paper presents an optimization procedure for a transformer-based solid-state pulse modulator with an additional damping network at the load. The design of the pulse transformer and the damping network are combined in the procedure, so that pulses with pulse lengths in the µs-range with a fast rise time and a compact transformer volume can be achieved.
	Optimal gapped boost inductor design for power factor correction applications   By Wai KeuEbel ng MO	[View]   [Download]
Abstract: This paper summarizes the winding geometrical and core gap effects on inductor winding loss. Relevant DC and AC winding resistance equations are derived and an optimal inductor design is given for the ratio of direct to ripple current k=Iav/delta I . A new concept of a curve-gapped inductor solution is proposed to improve the line harmonic current for lighting equipment.
	Optimized Planar Inductor for a High Current 3.5 kW Isolated DC/DC Converter   By Christian ØSTERGAARD	[View]   [Download]
Abstract: The paper presents several planar inductors optimized for low power loss in a 5kW isolated full-bridge forward converter, which is operated at a large output current. The inductors are optimized by use of a winding configuration which is proven to have an AC-resistance that are unaffected by the height and parallel connection of the turns in its winding configuration. The current density is simulated in the turns of the inductors by using finite element method analysis with the Ansys Maxwell software. The Ansys simulations have an excellent accuracy which is proved by comparing the simulated equivalent circuit parameters values with measurements from an impedance analyzer. Two inductors are designed and constructed, and their total power loss is measured in the converter and compared. The peak-efficiency of the converter that utilizes the inductor with the lowest loss is measured to 97.3 \%.
	Outcome Improvement for Pilot Diode Reverse Conducting IGBTs through Selective Locking Time Reduction in Diode Mode   By Daniel LEXOW	[View]   [Download]
Abstract: Pilot Diode (PD)-Reverse Conducting (RC)-IGBTs reverse-recovery and turn-ON losses significantly depend on the system's inverter locking time. Therefore, loss reduction is achievable by selectively reducing the inverter locking time in diode conduction mode. A sophisticated gate-control mechanism providing a safe and simple way to do so as well as high voltage simulations approving the method's functionality are presented.
	Performance Comparison between Phase Control, Pulse Power and Bidirectional Power Thyristors under ac Surge Conditions   By Fernando AMARAL	[View]   [Download]
Abstract: This paper presents a comparative analysis between different types of thyristor technologies (phase control, pulse power and bidirectional) with respect to their supportability to single- and multi-cycle sinusoidal ac current surges. The methodology adopted is entirely based on data sheet information. The main contribution of this paper is to provide a comprehensive insight regarding the device that best suits such applications. Three sets of commercial devices, including the three technologies, will be evaluated. Their data sheet parameters will be compared and their performance when submitted to predefined surge profiles will be investigated both in simulation and experimental fields. The main contributions of this paper are the proposition and demonstration of a useful method to compare different thyristors for ac surge conditions and the demonstration of its effectiveness by the comparison of several devices.
	RadPTDesigner: A program for designing radial mode piezoelectric transformers for inductorless inverters   By Jack FORRESTER	[View]   [Download]
Abstract: Piezoelectric transformers (PTs) offer the possibility for designing compact and efficient power supplies featuring few components. PT power supplies are difficult to design owing to the fusion between resonant power conversion and materials science. This paper presents a program for designing radial-mode PTs.
	Scalable Multitasking Dynamic Pulse Based Reliability Stress Test for High Voltage Discrete Semiconductors   By Konstantinos PATMANIDIS	[View]   [Download]
Abstract: High voltage power electronic devices undergo various stressors in their application environment, leading to long-term degradation and final catastrophic failure. This accumulated damage needs to be investigated during the development phase, as well as its impact on the device long-term performance. Therefore, power semiconductors should be subjected to repetitive stress testing in order to study the aging mechanisms as well as potential unknown failures before commercializing. Additionally, owing to manufacturing process variations and material tolerances, it is imperative to stress a sufficient number of devices for a meaningful statistical analysis. Taking into account these facts, this paper introduces a scalable reliability stress test system that covers various dynamic pulse stress scenarios, such as short circuit (SC), unclamped inductive switching (UIS) and double pulse testing (DPT), while assuring its robustness under worst-case conditions.
	Series Connection of 10 kV SiC Current Switches for PWM Current Source Converter Based High Power 7.2 kV Motor Drive Applications   By Ashish KUMAR	[View]   [Download]
Abstract: For the first time, two series-connected 10 kV SiC reverse-blocking switch (referred to as the current switch in this paper) consisting of the recently developed 10 kV SiC MOSFET and 10 kV SiC diode is proposed and experimentally demonstrated for a pulse width modulated current source inverter (PWM-CSI) based 7.2 kV motor drive applications. A passive RC snubber-based voltage balancing circuit is demonstrated to show excellent voltage sharing in the hard-switched conditions. The series-connected 10 kV current switch is characterized up to 6 kV blocking voltage. The experimental results show 98.6\\% efficiency at 10 kHz switching frequency for the 7.2 kV, 150 kVA PWM-CSI motor drive. The high switching frequency results in a 24 times smaller dc link inductor than the 6.5 kV silicon SGCT-based PWM-CSIs switched at 420 Hz.
	Set-up and measurements on a Mn-Zn ferrite ring core under sinusoidal excitation and dc bias conditions   By Teodora TODOROVA	[View]   [Download]
Abstract: This paper introduces a set-up for core loss measurements of Mn-Zn ferrite ring cores under sinusoidal excitation and dc bias conditions. The set-up is based on a tailor-made cost-efficient power amplifier. Measurements are performed on a non-gapped core at room temperature and 100 kHz operating frequency, where both pure ac excitations and such with various levels of dc biasing are considered. Data regarding the resultant B-H loops, volumetric power loss figures and effective amplitude permeability are presented. The results show that with dc bias the effective amplitude permeability of a non-gapped core is not a symmetrical quantity. Considerations regarding the utilization of the amplifier are discussed.
	Switching Behavior and Comparison of Wide Bandgap Devices for AutomotiveApplications   By Joao SOARES DE OLIVEIRA	[View]   [Download]
Abstract: Wide Bandgap devices allow building more compact power converters. To study these new devices (SiC and GaN), static and dynamic tests are performed to models validating. A simulation for each target device is developed considering the main parasitic elements and the measurement instrument models. Thus, the switching losses are calculated and compared to experimental results. Since the whole system is validated, in order to compare the SiC and GaN devices for automotive applications, a DC-DC converter simulation is used for comparing each device under different operation points. Measurement results are presented to validate the simulation approach.
	Switching Loss Estimation - A Thermal Approach Applied to GaN-Half-Bridge Configuration   By Benedikt KOHLHEPP	[View]   [Download]
Abstract: Modern SiC and GaN devices feature superior switching behavior compared to conventional device technologies. Thus, high switching frequencies become more attractive, but for that, reliable data for switching losses are vital. Nevertheless, the switching losses of the devices are quite difficult to obtain by electrical measurements due to the high voltage and current slew rates. As a result, conventional double pulse tests cannot be beneficially applied. Consequently, this paper presents another approach using thermal measurements to gain data concerning switching losses for GaN-HEMTs. Besides a test setup description, first results are provided as well to show the applicability. Furthermore, the paper delivers the limits and possible pitfalls during measurement.
	Thermal Design Comparison of Various Natural Convection Cooling Concepts of Discrete SiC-MOSFETs   By Sebastian RODE	[View]   [Download]
Abstract: In power converters, the choice of semiconductors presents one with many options. Considering discrete semiconductors in standard packages, the semiconductor housing and resulting mounting technology have great influence on the overall cooling, cost, current load and converter performance. One decisive parameter is the thermal resistance of the complete cooling design. By now, the total design impact of the semiconductor package choice (surface-mounted and through-hole-mounted) is not thoroughly discussed in literature, thus, we present a comparison of five cooling assemblies for discrete SiC-MOSFETs with equal chip area. The naturally cooled arrangements differ in packaging (TO-263 and TO-247), the presence and absence of isolation, and PCB technology. The validated results provide information on the total thermal resistance, maximum achieved load current, and cost of the full cooling assemblies. Up to 48 \% greater DC load current can be achieved in the THT package compared to using an SMT package. The THT arrangements also show significantly lower cost. In addition, the used analytical calculation method can be used for sufficiently accurate estimation of thermal resistances, demonstrated by results with less than 10 \% deviation compared to the conducted measurements.
	Thyristor with an Integrated Element Optimized for Protection against Overvoltage Impulses with Low Rate of Rise   By Dmitry TITUSHKIN	[View]   [Download]
Abstract: This article discusses safe switching of a protective element integrated into a power thyristor in the formof a four-layer dynistor structure with a reduced avalanche breakdown voltage for protection againstovervoltage impulses with low rate of rise. This paper proposes criteria allowing to optimize the topologyof the cathodic shunting of the protective element to ensure its safe switching, and presents the resultsof experiments confirming the safe switching of the protective elements with an optimized topology.
	Turn-off strategies for low-saturation IGBTs to reduce turn-off losses   By Vishwas ACHARYA NAYAMPALLI	[View]   [Download]
Abstract: Loss-optimized turn-off strategies for modern 'low-saturation' IGBTs are considered in this paper. TCAD turn-off simulations of the considered approaches reveal the possibility of substantially reducing the turn-off energy losses for such a low saturation IGBT model. An FPGA-based gate driver is implemented and turn-off measurement results with the two-step feedforward-based desaturation pulse method are provided. These results have shown up to a 24\% reduction in turn-off energy losses for this most basic approach. Simulation results with various approaches are provided and these show a potential reduction of up to 50\% in turn-off energy losses.
	Utilization of SiC Avalanche Diode as a Solid-State Snubber   By Kunio KOSEKI	[View]   [Download]
Abstract: A method to utilize avalanche diode as a solid-state snubber, in which a resistor is connected in series, is proposed. The proposed method was evaluated experimentally in a half-bridge circuit with an inductive load and successfully demonstrated the operational performance in reduction of surge voltage, voltage ringing, and power dissipation.