| 1. |
- Colmenares, Juan, et al.
(författare)
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Dual-Function Gate Driver for a Power Module With SiC Junction Field-Effect Transistors
- 2014
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Ingår i: IEEE transactions on power electronics. - : IEEE. - 0885-8993 .- 1941-0107. ; 29:5, s. 2367-2379
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Tidskriftsartikel (refereegranskat)abstract
- Silicon Carbide high-power modules populated with several parallel-connected junction field-effect transistors must be driven properly. Parasitic elements could act as drawbacks in order to achieve fast and oscillation-free switching performance, which are the main goals. These two requirements are related closely to the design of the gate-drive unit, and they must be kept under certain limits when high efficiencies are targeted. This paper deeply investigates several versions of gate-drive units and proposes a dual-function gate-drive unit which is able to switch the module with an acceptable speed without letting the current suffer from significant oscillations. It is experimentally shown that turn-on and turn-off switching times of approximately 130 and 185 ns respectively can be reached, while the magnitude of the current oscillations is kept at an adequate level. Moreover, using the proposed gate driver an efficiency of approximately 99.7% is expected for a three-phase converter rated at 125 kVA and having a switching frequency of 2 kHz.
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| 2. |
- Colmenares, Juan, et al.
(författare)
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High-Efficiency 312-kVA Three-Phase Inverter Using Parallel Connection of Silicon Carbide MOSFET Power Modules
- 2015
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Ingår i: IEEE transactions on industry applications. - : IEEE. - 0093-9994 .- 1939-9367. ; 51:6, s. 4664-4676
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents the design process of a 312-kVA three-phase silicon carbide inverter using ten parallel-connected metal-oxide-semiconductor field-effect-transistor power modules in each phase leg. The design processes of the gate-drive circuits with short-circuit protection and power circuit layout are also presented. Measurements in order to evaluate the performance of the gate-drive circuits have been performed using a double-pulse setup. Moreover, electrical and thermal measurements in order to evaluate the transient performance and steady-state operation of the parallel-connected power modules are shown. Experimental results showing proper steady-state operation of the power converter are also presented. Taking into account measured data, an efficiency of approximately 99.3% at the rated power has been measured for the inverter.
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| 3. |
- Colmenares, Juan, et al.
(författare)
-
High-efficiency three-phase inverter with SiC MOSFET power modules for motor-drive applications
- 2014
-
Konferensbidrag (refereegranskat)abstract
- This paper presents the design process of a 312 kVA three-phase silicon carbide inverter using ten parallel-connected metal-oxide-semiconductor field-effect-transistor power modules in each phase-leg. The design processes of the gate-drive circuits with short-circuit protection and the power circuit layout are also presented. Electrical measurements in order to evaluate the performance of the gate-drive circuits have been performed using a double-pulse setup. Experimental results showing the electrical performance during steady-state operation of the power converter are also shown. Taking into account measured data, an efficiency of approximately 99.3% at the rated power has been estimated for the inverter.
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| 4. |
- Colmenares, Juan, 1989-, et al.
(författare)
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Reliability Analysis of a High-Efficiency SiC Three-Phase Inverter
- 2016
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Ingår i: IEEE Journal of Emerging and Selected Topics in Power Electronics. - : IEEE. - 2168-6777 .- 2168-6785. ; 4:3, s. 996-1006
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Tidskriftsartikel (refereegranskat)abstract
- Silicon carbide as an emerging technology offers potential benefits compared with the currently used silicon. One of these advantages is higher efficiency. If this is targeted, reducing the on-state losses is a possibility to achieve it. Parallel-connecting devices decrease the on-state resistance and therefore reduce the losses. Furthermore, increasing the amount of components such as parallel connection of devices introduces an undesired tradeoff between efficiency and reliability, since an increased component count increases the probability of failure. A reliability analysis has been performed on a three-phase inverter rated at 312 kVA, using parallel-connected power modules. This analysis shows that the gate voltage stress has a high impact on the reliability of the complete system. Decreasing the positive gate-source voltage could, therefore, increase the reliability of the system approximately three times without affecting the efficiency significantly. Moreover, adding redundancy in the system could also increase the mean time to failure by approximately five times.
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| 5. |
- Colmenares, Juan, 1989-, et al.
(författare)
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Reliability analysis of a high-efficiency SiC three-phase inverter for motor drive applications
- 2016
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Ingår i: 2016 IEEE Applied Power Electronics Conference and Exposition (APEC). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467395502 ; , s. 746-753
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Konferensbidrag (refereegranskat)abstract
- Silicon Carbide as an emerging technology offers potential benefits compared to the currently used Silicon. One of these advantages is higher efficiency. If this is targeted, reducing the on-state losses is a possibility to achieve it. Parallel-connecting devices decrease the on-state resistance and therefore reducing the losses. Furthermore, increasing the amount of components introduces an undesired tradeoff between efficiency and reliability. A reliability analysis has been performed on a three-phase inverter for motor drive applications rated at 312 kVA. This analysis has shown that the gate voltage stress determines the reliability of the complete system. Nevertheless, decreasing the positive gate-source voltage could increase the reliability of the system approximately 8 times without affecting the efficiency significantly. Moreover, adding redundancy in the system could also increase the mean time to failure approximately 5 times.
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| 6. |
- De Lauretis, Maria, 1987-, et al.
(författare)
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Thermal impedances and temperature sensors : a combined approach for a novel thermal model of power semiconductors
- 2020
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Ingår i: 2020 22nd European Conference on Power Electronics and Applications (EPE'20 ECCE Europe). - : IEEE.
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Konferensbidrag (refereegranskat)abstract
- Power semiconductors, or transistors, constitute the core part of adjustable speed drives, which are commonly used in motor drive applications. Overheat of the semiconductors can compromise their behavior and, eventually, shorten the lifespan of the whole system. Therefore, the thermal management of transistors is crucial both at the design stage and during operation. Commonly performed thermal simulations normally rely on transistor thermal resistance. However, this approach does not account for the thermal behavior in transient regime. Furthermore, it is inappropriate for intermittent applications, such as for drilling machines, where the motor is on and off in repetitive working cycles, and the transistors never reach the equilibrium temperature. The transient thermal behavior is described by the concept of transfer thermal impedance. The transfer junction-to-case thermal impedance is given in the datasheet and assumes a constant ambient temperature; an assumption that is, however, not true in real applications. In this paper, we overcome this main limitation by using a resistive sensor. We consider MOSFETs in a 3-phase inverter, and model their thermal behavior with a well-known algorithm that uses the junction-to-case and junction-to-ambient thermal impedances, along with application dependent parameters. The actual rise of ambient temperature of the circuit board is included in the algorithm by virtue of the resistive sensor. The method has been validated with lab measurements, for two different MOSFETs. The proposed method can be used both at the design stage and during operation of the motor drive. Future works will include refinements of the power loss formulas, of the junction-to-ambient impedance modeling, as well as aging effects of the transistors.
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| 7. |
- Lim, Jang-Kwon, et al.
(författare)
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Evaluation of buried grid JBS diodes
- 2014
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Ingår i: 15th International Conference on Silicon Carbide and Related Materials, ICSCRM 2013. - : Trans Tech Publications Inc.. - 9783038350101 ; , s. 804-807
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Konferensbidrag (refereegranskat)abstract
- The 4H-SiC Schottky barrier diodes for high temperature operation over 200 °C have been developed using buried grids formed by implantation. Compared to a conventional JBS-type SBD with surface grid (SG), JBS-type SBD with buried grid (BG) has significantly reduced leakage current at reverse bias due to a better field shielding of the Schottky contact. By introducing the BG technology, the 1.7 kV diodes with an anode area 0.0024 cm2 (1 A) and 0.024 cm2 (10 A) were successfully fabricated, encapsulated in TO220 packages, and electrically evaluated. Two types of buried grid arrangement with different grid spacing dimensions were investigated. The measured IV characteristics were compared with simulation. The best fit was obtained with an active area of approximately 60% and 70% of the anode area in large and small devices, respectively. The measured values of the device capacitances were 1000 pF in large devices and 100 pF in small devices at zero bias. The capacitance values are proportional to the device area. The recovery behavior of big devices was measured in a double pulse tester and simulated. The recovery charge, Qc, was 18 nC and 24 nC in simulation and measurement, respectively. The fabricated BG JBS-type SBDs have a smaller maximum reverse recovery current compared to the commercial devices. No influence of the different grid spacing on the recovery charge was observed.
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| 8. |
- Sadik, Diane-Perle, et al.
(författare)
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Analysis of Parasitic Elements of SiC Power Modules With Special Emphasis on Reliability Issues
- 2016
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Ingår i: IEEE Journal of Emerging and Selected Topics in Power Electronics. - : IEEE. - 2168-6777 .- 2168-6785. ; 4:3, s. 988-995
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Tidskriftsartikel (refereegranskat)abstract
- Commercially available silicon carbide (SiC) MOSFET power modules often have a design based on existing packages previously used for silicon insulated-gate bipolar transistors. However, these packages are not optimized to take advantage of the SiC benefits, such as high switching speeds and high-temperature operation. The package of a half-bridge SiC MOSFET module has been modeled and the parasitic elements have been extracted. The model is validated through experiments. An analysis of the impact of these parasitic elements on the gate-source voltage on the chip has been performed for both low switching speeds and high switching speeds. These results reveal potential reliability issues for the gate oxide if higher switching speeds are targeted.
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| 9. |
- Sadik, Diane-Perle, et al.
(författare)
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Analysis of Parasitic Elements of SiC Power Modules with Special Emphasis on Reliability Issues
- 2016
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Ingår i: 31st Annual IEEE Applied Power Electronics Conference and Exposition, APEC 2016. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467395502 - 9781467383936 ; , s. 1018-1023
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Konferensbidrag (refereegranskat)abstract
- Commercially available Silicon Carbide (SiC) MOSFET power modules often have a design based on existing packages previously used for silicon insulated-gate bipolar transistors. However, these packages are not optimized to take advantage of the SiC benefits, such as, high switching speeds and high-temperature operation. The package of a half-bridge SiC MOSFET module has been modeled and the parasitic elements have been extracted. The model is validated through experiments. An analysis of the impact of these parasitic elements on the gate-source voltage on the chip has been performed for both low switching speeds and high switching speeds. These results reveal potential reliability issues for the gate-oxide if higher switching speeds are targeted.
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| 10. |
- Sadik, Diane-Perle, 1988-, et al.
(författare)
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Analysis of short-circuit conditions for silicon carbide power transistors and suggestions for protection
- 2014
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Ingår i: 2014 16th European Conference on Power Electronics and Applications, EPE-ECCE Europe 2014. - : IEEE. - 9781479930159 ; , s. 6910789-
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Konferensbidrag (refereegranskat)abstract
- An experimental analysis of the behavior under short-circuit conditions of three different Silicon Carbide (SiC) 1200 V power devices is presented. It is found that all devices take up a substantial voltage, which is favorable for detection of short-circuits. A suitable method for short-circuit detection without any comparator is demonstrated. A SiC JFET driver with an integrated short-circuit protection (SCP) is presented where a short-circuit detection is added to a conventional driver design in a simple way. Experimental tests of the SCP driver operating under short-circuit condition and under normal operation are performed successfully.
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| 11. |
- Sadik, Diane-Perle, 1988-, et al.
(författare)
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Comparison of thermal stress during short-circuit in different types of 1.2 kV SiC transistors based on experiments and simulations
- 2016
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Ingår i: Materials Science Forum. - : Trans Tech Publications Inc.. - 9783035710434 ; , s. 595-598
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Konferensbidrag (refereegranskat)abstract
- The temperature evolution during a short-circuit in the die of three different Silicon Carbide 1200-V power devices is presented. A transient thermal simulation was performed based on the reconstructed structure of commercially available devices. The location of the hottest point in the device is compared. Finally, the analysis supports the necessity to turn off short-circuit events rapidly in order to protect the device after a fault.
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| 12. |
- Sadik, Diane-Perle, et al.
(författare)
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Experimental investigations of static and transient current sharing of parallel-connected silicon carbide MOSFETs
- 2013
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Ingår i: 2013 15th European Conference on Power Electronics and Applications, EPE 2013. - 9781479901166
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Konferensbidrag (refereegranskat)abstract
- An Experimental performance analysis of a parallel connection of two 1200/80 MΩ silicon carbide SiC MOSFETs is presented. Static parallel connection was found to be unproblematic. The switching performance of several pairs of parallel-connected MOSFETs is shown employing a common simple totem-pole driver. Good transient current sharing and high-speed switching waveforms with small oscillations are presented. To conclude this analysis, a dc/dc boost converter using parallel-connected SiC MOSFETs is designed for stepping up a voltage from 50 V to 560 V. It has been found that at high frequencies, a mismatch in switching losses results in thermal unbalance between the devices.
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| 13. |
- Sadik, Diane-Perle, 1988-, et al.
(författare)
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Humidity Testing of SiC Power MOSFETs – An Update
- 2017
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Ingår i: 2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE EUROPE). - : Institute of Electrical and Electronics Engineers (IEEE).
-
Konferensbidrag (refereegranskat)abstract
- The effect of humidity on SiC Power MOSFET modules is investigated in a real application. Four modules are operated outdoor and four modules are operated indoor in identical setups, while their breakdown voltages are monitored regularly. The evolution of the leakage current, indicating humidity-induced degradation is observed.
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| 14. |
- Sadik, Diane-Perle, et al.
(författare)
-
Impact of blanking time on switching losses in a SiC MOSFET-based converter using capacitive snubbers
- 2019
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Ingår i: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe. - : Institute of Electrical and Electronics Engineers (IEEE). - 9789075815313
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Konferensbidrag (refereegranskat)abstract
- Wide Bandgap power semiconductors such as SiC MOSFETs, have enabled compact and highly efficient power converters operated at higher frequencies. In converters using SiC MOSFETs and capacitive snubbers, the blanking times may have a significant impact on switching losses. The power losses induced by unnecessary long blanking times have been quantified experimentally. It was found that, at 100 kHz, an adaptive blanking time can reduce the losses by more than 20 %. As those losses are directly proportional to the switching frequency, an adaptive blanking time is essential when designing for high operation frequencies. Doing so, higher operation frequencies are possible while maintaining a high efficiency.
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| 15. |
- Sadik, Diane-Perle, 1988-, et al.
(författare)
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Introduction of SiC MOSFETs in Converters based on Si IGBTs : A Reliability and Efficiency Analysis
- 2017
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Ingår i: 2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia, IFEEC - ECCE Asia 2017. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509051571 ; , s. 1680-1685
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Konferensbidrag (refereegranskat)abstract
- Silicon Carbide (SiC) Metal-Oxide-Semiconductor Field-Effect Transistors (MOSFETs) have the potential to increase the power density in power electronics converters compared to the currently used silicon (Si). Their benefits are higher efficiency, higher switching speeds, and higher operating temperatures. Moreover, SiC MOSFETs, which are normally-off, offer the possibility to directly replace Si Isolated-Gate-BipolarTransistors (IGBTs) in already existing converter designs with minimal circuit changes. Nevertheless, as an emerging technology, the reliability performance remains to be investigated. A reliability analysis has been performed based on a full-bridge resonant converter rated at 60 kW for modern Electrostatic Precipitator (ESP) power supplies. This analysis shows that introducing SiC devices will increase the lifetime of the converter while reducing the losses. The investment costs of replacing the Si IGBTs with SiC MOSFETs can thus be covered with the reduction of the losses over the economical operational lifetime. Furthermore, a theoretical analysis on how introducing SiC MOSFETs could increase the power density of the converter while maintaining the efficiency and the reliability. Finally, an analysis on introducing redundancy as a way to improve the reliability of the system has been performed.
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| 16. |
- Sadik, Diane-Perle, et al.
(författare)
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Investigation of long-term parameter variations of SiC power MOSFETs
- 2015
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Ingår i: Power Electronics and Applications (EPE’15 ECCE-Europe), 2015 17th European Conference on. - : IEEE. ; , s. 1-10
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Konferensbidrag (refereegranskat)abstract
- Experimental investigations on the gate-oxide and body-diode reliability of commercially available Silicon Carbide (SiC) MOSFETs from the second generation are performed. The body-diode conduction test is performed with a current density of 50 A/cm2 in order to determine if the body-diode of the MOSFETs is free from bipolar degradation. The second test is stressing the gate-oxide. A negative bias is applied on the gate oxide in order to detect and quantify potential drifts.
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| 17. |
- Sadik, Diane-Perle, et al.
(författare)
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Investigation of the surge current capability of the body diode of SiC MOSFETs for HVDC applications
- 2016
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Ingår i: 2016 18th European Conference on Power Electronics and Applications (EPE'16 ECCE Europe). - : IEEE. - 9789075815245
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Konferensbidrag (refereegranskat)abstract
- The surge current capability of the body-diode of SiC MOSFETs is experimentally analyzed in order to investigate the possibility of using SiC MOSFETs for HVDC applications. SiC MOSFET discrete devices and modules have been tested with surge currents up to 10 times the rated current and for durations up to 2 ms. Although the presence of stacking faults cannot be excluded, the experiments reveal that the failure may occur due to the latch-up of the parasitic n-p-n transistor located in the SiC MOSFET.
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| 18. |
- Sadik, Diane-Perle, 1988-
(författare)
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On Reliability of SiC Power Devices in Power Electronics
- 2017
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Silicon Carbide (SiC) is a wide-bandgap (WBG) semiconductor materialwhich has several advantages such as higher maximum electric field, lowerON-state resistance, higher switching speeds, and higher maximum allowablejunction operation temperature compared to Silicon (Si). In the 1.2 kV - 1.7kV voltage range, power devices in SiC are foreseen to replace Si Insulatedgatebipolar transistors (IGBTs) for applications targeting high efficiency,high operation temperatures and/or volume reductions. In particular, theSiC Metal-oxide semiconductor field-effect transistor (MOSFET) – which isvoltage controlled and normally-OFF – is the device of choice due to the easeof its implementation in designs using Si IGBTs.In this work the reliability of SiC devices, in particular that of the SiCMOSFET, has been investigated. First, the possibility of paralleling two discreteSiC MOSFETs is investigated and validated through static and dynamictests. Parallel-connection was found to be unproblematic. Secondly, drifts ofthe threshold voltage and forward voltage of the body diode of the SiC MOSFETare investigated through long-term tests. Also these reliability aspectswere found to be unproblematic. Thirdly, the impact of the package on thechip reliability is discussed through a modeling of the parasitic inductancesof a standard module and the impact of those inductances on the gate oxide.The model shows imbalances in stray inductances and parasitic elementsthat are problematic for high-speed switching. A long-term test on the impactof humidity on junction terminations of SiC MOSFETs dies and SiCSchottky dies encapsulated in the same standard package reveals early degradationfor some modules situated outdoors. Then, the short-circuit behaviorof three different types (bipolar junction transistor, junction field-effect transistor,and MOSFET) of 1.2 kV SiC switching devices is investigated throughexperiments and simulations. The necessity to turn OFF the device quicklyduring a fault is supported with a detailed electro-thermal analysis for eachdevice. Design guidelines towards a rugged and fast short-circuit protectionare derived. For each device, a short-circuit protection driver was designed,built and validated experimentally. The possibility of designing diode-lessconverters with SiC MOSFETs is investigated with focus on surge currenttests through the body diode. The discovered fault mechanism is the triggeringof the npn parasitic bipolar transistor. Finally, a life-cycle cost analysis(LCCA) has been performed revealing that the introduction of SiC MOSFETsin already existing IGBT designs is economically interesting. In fact,the initial investment is saved later on due to a higher efficiency. Moreover,the reliability is improved, which is beneficial from a risk-management pointof-view. The total investment over 20 years is approximately 30 % lower fora converter with SiC MOSFETs although the initial converter cost is 30 %higher.
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| 19. |
- Sadik, Diane-Perle, 1988-, et al.
(författare)
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Short-Circuit Protection Circuits for Silicon-Carbide Power Transistors
- 2016
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Ingår i: IEEE Transactions on Industrial Electronics. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0278-0046 .- 1557-9948. ; 63:4, s. 1995-2004
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Tidskriftsartikel (refereegranskat)abstract
- An experimental analysis of the behavior under short-circuit conditions of three different silicon-carbide (SiC) 1200-V power devices is presented. It is found that all devices take up a substantial voltage, which is favorable for detection of short circuits. A transient thermal device simulation was performed to determine the temperature stress on the die during a short-circuit event, for the SiC MOSFET. It was found that, for reliability reasons, the short-circuit time should be limited to values well below Si IGBT tolerances. Guidelines toward a rugged design for short-circuit protection (SCP) are presented with an emphasis on improving the reliability and availability of the overall system. A SiC device driver with an integrated SCP is presented for each device-type, respectively, where a short-circuit detection is added to a conventional driver design in a simple way. The SCP driver was experimentally evaluated with a detection time of 180 ns. For all devices, short-circuit times well below 1 s were achieved.
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| 20. |
- Velander, E., et al.
(författare)
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Analysis of short circuit type II and III of high voltage SiC MOSFETs with fast current source gate drive principle
- 2016
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Ingår i: 2016 IEEE 8th International Power Electronics and Motion Control Conference, IPEMC-ECCE Asia 2016. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509012107 ; , s. 3392-3397
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Konferensbidrag (refereegranskat)abstract
- The Silicon Carbide (SiC) MOSFET is considered to be the leading candidate for future 1.7 kV and 3.3 kV switches in 2-level voltage source converters (VSC) up to 2 MW. For those converters, short circuit (SC) in the dc-link loop can occur due to a number of reasons, e.g. faulty semiconductor modules, faulty gate drivers (GDs), or electro-magnetic interference (EMI). Termination of such SCs is important in order to protect components and reduce the damage in the converter box. This paper presents a new short circuit protection scheme based on a universal current-source GD principle without dedicated hardware components. The performance of the design is evaluated for SC in the dc-link loop under load conditions, called type II and type III. Moreover, measurement results are presented using the proposed GD connected to a 1700 V 300 A SiC MOSFET tested during SC type II and III at two different dc-link stray inductances, 30 nH and 100 nH, and at two different temperatures, 25 °C and 125 °C. The conclusions are that the proposed scheme is able to terminate both SC type II and III with fast reaction time, with low energy dissipation, with a margin of about 15 times below the destructive level for dc-link voltages and load currents up to 1050 V and 300 A respectively.
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