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  • 1.
    Colmenares, Juan
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Peftitsis, Dimosthenis
    Rabkowski, Jacek
    Sadik, Diane-Perle
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    High-Efficiency 312-kVA Three-Phase Inverter Using Parallel Connection of Silicon Carbide MOSFET Power Modules2015Ingår i: IEEE transactions on industry applications, ISSN 0093-9994, E-ISSN 1939-9367, Vol. 51, nr 6, s. 4664-4676Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    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.

  • 2.
    Colmenares, Juan
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Peftitsis, Dimosthenis
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Sadik, Diane-Perle
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Rabkowski, Jacek
    High-efficiency three-phase inverter with SiC MOSFET power modules for motor-drive applications2014Konferensbidrag (Refereegranskat)
    Abstract [en]

    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.

  • 3.
    Lim, Jang-Kwon
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik (stängd 20110930).
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik (stängd 20110930).
    Peftitsis, Dimosthenis
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik (stängd 20110930).
    Rabkowski, Jacek
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik (stängd 20110930).
    Bakowski, Mietek
    Acreo, Kista.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik (stängd 20110930).
    Comparison of total losses of 1.2 kV SiC JFET and BJT in DC-DC converter including gate driver2011Ingår i: Materials Science Forum, ISSN 0255-5476, E-ISSN 1662-9752, Vol. 679/680, s. 649-652Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The 1.2 kV SiC JFET and BJT devices have been investigated and compared with respect to total losses including the gate driver losses in a DC-DC converter configuration. The buried grid, Normally-on JFET devices with threshold voltage of -50 V and -10V are compared to BJT devices with ideal semiconductor and passivating insulator interface and an interface with surface recombination velocity of 4.5·104 cm/s yielding agreement to the reported experimental current gain values. The conduction losses of both types of devices are independent of the switching frequency while the switching losses are proportional to the switching frequency. The driver losses are proportional to the switching frequency in the JFET case but to a large extent independent of the switching frequency in the BJT case. The passivation of the emitter junction modeled here by surface recombination velocity has a significant impact on conduction losses and gate driver losses in the investigated BJT devices.

  • 4.
    Nee, Hans-Peter
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Rabkowski, Jacek
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Peftitsis, Dimosthenis
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Colmenares, Juan
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Sadik, Diane
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Bakowski, Mietek
    Acreo Swedish ICT AB, Sweden.
    Lim, Jang-Kwon
    Acreo AB, Kista.
    Antonopoulos, Antonios
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ängquist, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Zdanowski, Mariusz
    Warsaw University of Technology.
    High-Efficiency Power Conversion Using Silicon Carbide Power Electronics2013Ingår i: Proc. of International Conference on silicon carbide and related materials (ICSCRM) 2013, Miyazaki, Japan, Sept. 29–Oct. 4, 2013, Trans Tech Publications Inc., 2013, s. 1083-1088Konferensbidrag (Refereegranskat)
    Abstract [en]

    The message of this paper is that the silicon carbide power transistors of today are good enough to design converters with efficiencies and switching speeds beyond comparison with corresponding technology in silicon. This is the time to act. Only in the highest power range the devices are missing. Another important step towards high powers is to find new solutions for multi-chip circuit designs that are adapted to the high possible switching speeds of unipolar silicon carbide power transistors.

  • 5.
    Peftitsis, Dimosthenis
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Baburske, R.
    Rabkowski, Jacek
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Lutz, J.
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Challenges regarding parallel connection of SiC JFETs2013Ingår i: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 28, nr 3, s. 1449-1463Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    State-of-the-art silicon carbide switches have current ratings that are not sufficiently high to be used in high-power converters. It is, therefore, necessary to connect several switches in parallel in order to reach sufficient current capabilities. An investigation of parallel-connected normally ON silicon carbide JFETs is presented in this paper. The device parameters that play the most important role for the parallel connection are the pinch-off voltage, the gate-source reverse breakdown voltage, the spread in the on-state resistances, and the variations in static transfer characteristics of the devices. Moreover, it is experimentally shown that a fifth factor affecting the parallel connection of the devices is the parasitic inductances of the circuit layout. The temperature dependence of the gate-source reverse breakdown voltages is analyzed for two different designs of silicon carbide JFETs. If the spread in the pinch-off and gate-source reverse breakdown voltages is sufficiently large, there might be no possibility for a stable off-state operation of a pair of transistors without forcing one of the gate voltages to exceed the breakdown voltage. A solution to this problem using individual gate circuits for the JFETs is given. The switching performance of two pairs of parallel-connected devices with different combinations of parameters is compared employing two different gate-driver configurations. Three different circuit layouts are considered and the effect of the parasitic inductances is experimentally investigated. It is found that using a single gate circuit for the two mismatched JFETs may improve the switching performance and therefore the distribution of the switching losses significantly. Based on the measured switching losses, it is also clear that regardless of the design of the gate drivers, the lowest total switching losses for the devices are obtained when they are symmetrically placed.

  • 6.
    Peftitsis, Dimosthenis
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik (stängd 20110930).
    Baburske, Roman
    Technische Universität Chemnitz.
    Rabkowski, Jacek
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik (stängd 20110930).
    Lutz, Josef
    Technische Universität Chemnitz.
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik (stängd 20110930).
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik (stängd 20110930).
    Challenges regarding parallel-connection of SiC JFETs2011Ingår i: IEEE 8th International Conference on Power Electronics and ECCE Asia (ICPE & ECCE), 2011: 'Green World with Power Electronics' / [ed] IEEE, 2011, s. 1095-1101Konferensbidrag (Refereegranskat)
    Abstract [en]

    Considering the present development of the available Silicon Carbide switches, their current ratings are so low that they cannot be used for high-power converters. It is therefore necessary to connect several switches in parallel in order to obtain sufficient current ratings. An investigation of parallel-connected normally-on Silicon Carbide Junction Field Effect Transistors is presented in this paper. The parameters that play the most important role for the parallel connection are the pinch-off and the gate-source breakdown voltages. The temperature dependency of those two voltages is analyzed based on the pnp structure of the device. If the spread in these parameters is sufficiently large there might be no possibility for a stable off-state operation of a pair of transistors without forcing one of the gate voltages to exceed the breakdown voltage, especially at high temperatures. A solution to this problem is given. The switching performance of two pairs of parallel-connected devices is compared with respect to their pinch-off voltages, and it is found that differences of approximately 25% in switching losses could result from a difference in the pinch-off voltage of 0.5 V.

  • 7.
    Peftitsis, Dimosthenis
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Lim, Jang-Kwon
    Acreo AB.
    Rabkowski, Jacek
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Experimental Comparison of Different Gate-Driver Configurations for Parallel-Connection of Normally-ON SiC JFETs2012Ingår i: 7th International Power Electronics and Motion Control Conference (IPEMC), 2012, IEEE conference proceedings, 2012, s. 16-22Konferensbidrag (Refereegranskat)
    Abstract [en]

    Due to the low current ratings of the currently available silicon carbide (SiC) switches they cannot be employed in high-power converters. Thus, it is necessary to parallel-connect several switches in order to reach higher current ratings. This paper presents an investigation of parallel-connected normally-on SiC junction field effect transistors. There are four crucial parameters affecting the effectiveness of the parallel-connected switches. However, the pinch-off voltage and the reverse breakdown voltage of the gates seem to be the most important parameters which affect the switching performance of the devices. In particular, the spread in these two parameters might affect the stable off-state operation of the switches. The switching performance and the switching losses of a pair of parallel-connected devices having different reverse breakdown voltages of the gates is investigated by employing three different gate-driver configurations. It is experimentally shown that using a single gate-driver circuit the switching performance of the parallel-connected devices is almost identical, while the total switching losses are lower compared to the other two configurations.

  • 8.
    Peftitsis, Dimosthenis
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik (stängd 20110930).
    Rabkowski, Jacek
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik (stängd 20110930).
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik (stängd 20110930).
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik (stängd 20110930).
    Experimental comparison of dc-dc boost converters with SiC JFETs and SiC bipolar transistors2011Ingår i: Proceedings of the 2011-14th European Conference on Power Electronics and Applications (EPE 2011) / [ed] EPE Association, 2011Konferensbidrag (Refereegranskat)
    Abstract [en]

    An experimental performance comparison between SiC JFET and SiC BJT switches which are used as the main switch for a 2 kW dc/dc converter is presented. In order to perform a fair comparison and due to the different chip areas of these two SiC devices, they both operate under the same on-state losses. Moreover, the switching speeds of the gate and base drivers are approximately equal. It is experimentally shown that the SiC BJT is switching slightly faster than the SiC JFET under the same circuit conditions, while the driver loss for the SiC BJT is higher than for the JFET, especially at relatively low switching frequencies. Various experimental results dealing with the switching performance of the SiC devices and the power losses at different switching frequencies are presented. It is found that the BJT converter has a higher efficiency (99.0% measured at 50 kHz) that the JFET converter.

  • 9.
    Peftitsis, Dimosthenis
    et al.
    KTH, Skolan för elektro- och systemteknik (EES).
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES).
    Antonopoulos, Antonios
    KTH, Skolan för elektro- och systemteknik (EES).
    Rabkowski, Jacek
    KTH, Skolan för elektro- och systemteknik (EES).
    Lim, Jang-Kwon
    Acreo, Kista.
    Bakowski, Mietek
    Acreo, Kista.
    Ängquist, Lennart
    KTH, Skolan för elektro- och systemteknik (EES).
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES).
    High-power modular multilevel converters with SiC JFETs2010Ingår i: 2010 IEEE Energy Conversion Congress and Exposition (ECCE) / [ed] IEEE, IEEE , 2010, s. 2148-2155Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper studies the possibility of building a Modular Multilevel Converter (M2C) using Silicon Carbide (SiC) switches. The main focus is on a theoretical investigation of the conduction losses of such a converter and a comparison to a corresponding converter with silicon insulated gate bipolar transistors. Both SiC BJTs and JFETs are considered and compared in order to choose the most suitable technology. One of the sub-modules of a down-scaled 10 kVA prototype M2C is replaced with a sub-module with SiC JFETs without anti-parallel diodes. It is shown that diode-less operation is possible with the JFETs conducting in the negative direction, leaving the possibility to use the body diode during the switching transients. Experimental waveforms for the SiC sub-module verify the feasibility during normal steady-state operation. The loss estimation shows that a 300 MW M2C for high-voltage direct current transmission would potentially have an efficiency of approximately 99,8 % if equipped with future 3.3 kV 1.2 kA SiC JFETs.

  • 10.
    Peftitsis, Dimosthenis
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Antonopoulos, Antonios
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Rabkowski, Jacek
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Lim, Jang-Kwon
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Bakowski, Mietek
    Acreo AB.
    Ängquist, Lennart
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    High-Power Modular Multilevel Converters With SiC JFETs2012Ingår i: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 27, nr 1, s. 28-36Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    This paper studies the possibility of building a modular multilevel converter (M2C) using silicon carbide (SiC) switches. The main focus is on a theoretical investigation of the conduction losses of such a converter and a comparison to a corresponding converter with silicon-insulated gate bipolar transistors. Both SiC BJTs and JFETs are considered and compared in order to choose the most suitable technology. One of the submodules of a down-scaled 3 kVA prototype M2C is replaced with a submodule with SiC JFETs without antiparallel diodes. It is shown that the diode-less operation is possible with the JFETs conducting in the negative direction, leaving the possibility to use the body diode during the switching transients. Experimental waveforms for the SiC submodule verify the feasibility during normal steady-state operation. The loss estimation shows that a 300 MW M2C for high-voltage direct current transmission would potentially have an efficiency of approximately 99.8% if equipped with future 3.3 kV 1.2 kA SiC JFETs.

  • 11.
    Rabkowski, Jacek
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Peftitsis, Dimosthenis
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Low-Loss High-Performance Base-Drive Unit for SiC BJTs2012Ingår i: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 27, nr 5, s. 2633-2643Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Driving a silicon carbide bipolar junction transistor is not a trivial issue, if low drive power consumption and short-switching times are desired. A dual-source base-drive unit with a speed-up capacitor consisting of a low-and a high-voltage source is, therefore, proposed in this paper. As a significant base current is required during the conduction state, the driver power consumption is higher than for other semiconductor switches. In the presented solution, the steady-state base current is provided by a low-voltage source and is optimized for lowpower losses. On the contrary, a second source with a higher voltage and speed-up capacitor is used in order to improve the switching performance of the device. The proposed driver has experimentally been compared to other standard driver solutions by using a double-pulse circuit and a 2-kW dc/dc boost converter. Switching times of 20 ns at turn-ON and 35 ns at turn-OFF were recorded. Finally, the efficiency of the converter was determined experimentally at various switching frequencies. From power loss measurements at 100-kHz switching frequency using the proposed driver in a 2-kW dc/dc boost converter, it was found that the efficiency was approximately 99.0%. In the same operating point, the driver power consumption was only 0.08% of the rated power.

  • 12. Ranstad, P.
    et al.
    Giezendanner, F.
    Bakowski, M.
    Lim, J. -K
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ranstad, A.
    SiC power devices in a soft switching converter including aspects on packaging2014Ingår i: ECS Transactions, 2014, Vol. 64, nr 7, s. 51-59Konferensbidrag (Refereegranskat)
    Abstract [en]

    In many applications of power electronic converters efficiency and size are important figures of merit. Low losses in the power semiconductors as well as high frequency operation are important factors to obtain compact and highly efficient converters. The converters considered in this paper are off-line industrial power supplies (~100 kW) operating at a switching frequency range of 20-40 kHz. Replacing Si power devices by SiC counterparts enables both lower losses and increased switching frequencies. In this paper, experimental results from SiC PiN diodes, (output rectifiers) and SiC MOSFETs, (active switches) are presented.

  • 13.
    Sadik, Diane-Perle
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Colmenares, Juan
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Peftitsis, Dimosthenis
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Rabkowski, Jacek
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Analysis of short-circuit conditions for silicon carbide power transistors and suggestions for protection2014Ingår i: 2014 16th European Conference on Power Electronics and Applications, EPE-ECCE Europe 2014, IEEE , 2014, s. 6910789-Konferensbidrag (Refereegranskat)
    Abstract [en]

    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.

  • 14.
    Sadik, Diane-Perle
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Colmenares, Juan
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Peftitsis, Dimosthenis
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Bakowski, Mietek
    Rabkowski, Jacek
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Short-Circuit Protection Circuits for Silicon Carbide Power Transistors2016Ingår i: IEEE transactions on industrial electronics (1982. Print), ISSN 0278-0046, E-ISSN 1557-9948, ISSN 0278-0046, Vol. 63, nr 4, s. 1995-2004, artikel-id ITIEDArtikel i tidskrift (Refereegranskat)
    Abstract [en]

    An experimental analysis of the behavior under short-circuit conditions of three different siliconcarbide (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 shortcircuit 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 µs were achieved.

  • 15.
    Tolstoy, Georg
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    High-Efficiency SiC Power Conversion: Base Drivers for Bipolar Junction Transistors and Performance Impacts on Series-Resonant Converters2015Doktorsavhandling, sammanläggning (Övrigt vetenskapligt)
    Abstract [en]

    This thesis aims to bring an understanding to the silicon carbide (SiC) bipolar junction transistor (BJT). SiC power devices are superior to the silicon IGBT in several ways. They are for instance, able to operate with higher efficiency, at higher frequencies, and at higher junction temperatures. From a system point of view the SiC power device could decrease the cost and complexity of cooling, reduce the size and weight of the system, and enable the system to endure harsher environments.

    The three main SiC power device designs are discussed with a focus on the BJT. The SiC BJT is compared to the SiC junction field-effect transistor (JFET) and the metal-oxide semiconductor field-effect transistor (MOSFET). The potential of employing SiC power devices in applications, ranging from induction heating to high-voltage direct current (HVDC), is presented.

    The theory behind the state-of-the-art dual-source (2SRC) base driver that was presented by Rabkowski et al. a few years ago is described. This concept of proportional base drivers is introduced with a focus on the discretized proportional base drivers (DPBD). By implementing the DPBD concept and building a prototype it is shown that the steady-state consumption of the base driver can be reduced considerably.

     The aspects of the reverse conduction of the SiC BJT are presented. It is shown to be of importance to consider the reduced voltage drop over the base-emitter junction.

    Last the impact of SiC unipolar and bipolar devices in series-resonant (SLR) converters is presented. Two full-bridges are designed and constructed, one with SiC MOSFETs utilizing the body diode for reverse conduction during the dead-time, and the second with SiC BJTs with anti-parallel SiC Schottky diodes. It is found that the SiC power devices, with their absence of tail current, are ideal devices to fully utilize the soft-switching properties that the SLR converters offer. The SiC MOSFET benefits from its possibility to utilize reverse conduction with a low voltage drop. It is also found that the size of capacitance of the snubbers can be reduced compare to state-of-the-art silicon technology. High switching frequencies of 200 kHz are possible while still keeping the losses low. A dead-time control strategy for each device is presented. The dual control (DuC) algorithm is tested with the SiC devices and compared to frequency modulation (FM).

    The analytical investigations presented in this thesis are confirmed by experimental results on several laboratory prototype converters.

  • 16.
    Tolstoy, Georg
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Larsson, Björn
    ABB Machines.
    Wallmark, Oskar
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Norrga, Staffan
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Elimination of vector changes due to sector changes with DTC2014Ingår i: 2014 16th European Conference on Power Electronics and Applications, EPE-ECCE Europe 2014, IEEE , 2014, s. 6910748-Konferensbidrag (Refereegranskat)
    Abstract [en]

    In this paper it has been investigated if there is a possibility to reduce the switching frequency for a two-level inverter by improving the direct torque control (DTC) algorithm by adding a non-switching condition when a new sector is entered. It is believed that the DTC switching table can be improved by adding a non-switching condition when sector change occurs. This will reduce the number of switching actions by up to 12 per electrical rotation without interfering with the electrical machine performance.

  • 17.
    Tolstoy, Georg
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik.
    Peftitsis, Dimosthenis
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik.
    Lim, Jang-Kwon
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik.
    Bakowski, Mietek
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik.
    Circuit Modeling of Vertical Buried-Grid SiC JFETs2010Ingår i: SILICON CARBIDE AND RELATED MATERIALS 2009, PTS 1 AND 2   / [ed] Bauer AJ; Friedrichs P; Krieger M; Pensl G; Rupp R; Seyller T, 2010, Vol. 645-648, s. 965-968Konferensbidrag (Refereegranskat)
    Abstract [en]

    The main problem when the conventional PSpice JFET model is used to simulate a vertical short-channel buried-grid JFET is caused by the constant values of Threshold Voltage (VTO) and Transconductance (BETA). This paper presents a new model for the vertical short-channel buried-grid 1200V JEET, where both VTO and BETA vary with respect to the Drain-Source voltage. Simulation data from Medici have been analyzed in order to extract the analytical equations for VTO and BETA. Also other PSpice parameters are extracted from these data. The proposed circuit model has been simulated in Matlab by optimizing the same algorithm that PSpice uses. A variety of results are shown and discussed in this paper.

  • 18.
    Tolstoy, Georg
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik.
    Peftitsis, Dimosthenis
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik.
    Rabkowski, Jacek
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektriska maskiner och effektelektronik.
    Performance tests of a 4, 1x4, 1mm(2) SiC LCVJFET for a DC/DC boost converter application2011Ingår i: SILICON CARBIDE AND RELATED MATERIALS 2010 / [ed] Monakhov EV; Hornos T; Svensson BG, 2011, Vol. 679-680, s. 722-725Konferensbidrag (Refereegranskat)
    Abstract [en]

    A 4.1x4.1mm(2), 100m Omega 1,2kV lateral channel vertical junction field effect transistor (LCVJFET) built in silicon carbide (SiC) from SiCED, to use as the active switch component in a high-temperature operation DC/DC-boost converter, has been investigated. The switching loss for room temperature (RT) and on-state resistance (Ron) for RT up to 170 degrees C is investigated. Since the SiC VJFET has a buried body diode it is also ideal to use instead of a switch and diode setup. The voltage drop over the body diode decreases slightly with a higher temperature. A short-circuit test has also been conducted, which shows a high ruggedness.

  • 19.
    Tolstoy, Georg
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Peftitsis, Dimosthenis
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Rabkowski, Jacek
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Palmer, P. R.
    A discretized proportional base driver for Silicon Carbide Bipolar Junction Transistors2013Ingår i: 2013 IEEE ECCE Asia Downunder - 5th IEEE Annual International Energy Conversion Congress and Exhibition, IEEE ECCE Asia 2013, IEEE , 2013, s. 728-735Konferensbidrag (Refereegranskat)
    Abstract [en]

    Silicon Carbide Bipolar Junction Transistors require a continuous base current in the on-state. This base current is usually made constant and is corresponding to the maximum collector current and maximum junction temperature that is foreseen in a certain application. In this paper, a discretized proportional base driver is proposed which will reduce, for the right application, the steady-state power consumption of the base driver. The operation of the proposed base driver has been verified experimentally, driving a 1200V/40A SiC BJT in a DC-DC boost converter. In order to determine the potential reduction of the power consumption of the base driver, a case with a dc-dc converter in an ideal electric vehicle driving the new European drive cycle has been investigated. It is found that the steady-state power consumption of the base driver can be reduced by approximately 63 %. The total reduction of the driver consumption is 2816 J during the drive cycle, which is slightly more than the total on-state losses for the SiC BJTs used in the converter.

  • 20.
    Tolstoy, Georg
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Peftitsis, Dimosthenis
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Rabkowski, Jacek
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Palmer, Patrick R.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    A Discretized Proportional Base Driver for Silicon Carbide Bipolar Junction Transistors2014Ingår i: IEEE transactions on power electronics, ISSN 0885-8993, E-ISSN 1941-0107, Vol. 29, nr 5, s. 2408-2417Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Silicon carbide (SiC) bipolar junction transistors (BJTs) require a continuous base current in the on-state. This base current is usually made constant and is corresponding to the maximum collector current and maximum junction temperature that is foreseen in a certain application. In this paper, a discretized proportional base driver is proposed which will reduce, for the right application, the steady-state power consumption of the base driver. The operation of the proposed base driver has been verified experimentally, driving a 1200-V/40-A SiC BJT in a dc-dc boost converter. In order to determine the potential reduction of the power consumption of the base driver, a case with a dc-dc converter in an ideal electric vehicle driving the new European drive cycle has been investigated. It is found that the steady-state power consumption of the base driver can be reduced by approximately 60%. The total reduction of the driver consumption is 3459 J during the drive cycle, which is slightly more than the total on-state losses for the SiC BJTs used in the converter.

  • 21.
    Tolstoy, Georg
    et al.
    KTH.
    Ranstad, P.
    Colmenares, Juan
    KTH.
    Giezendanner, F.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Dual control used in series-loaded resonant converter with SiC devices2015Ingår i: Power Electronics and ECCE Asia (ICPE-ECCE Asia), 2015 9th International Conference on, IEEE , 2015, s. 495-501Konferensbidrag (Refereegranskat)
    Abstract [en]

    This paper presents the performance of silicon carbide (SiC) switches in a series-loaded resonant (SLR) converter with dual control (DuC). It is shown that the SiC metal oxide-semiconductor field-effect transistor (MOSFET) with DuC increases the overall efficiency of the SLR converter compared to frequency modulation (FM). For the SiC bipolar junction transistors (BJT), the loss reduction with DuC instead of FM is not as dramatic as for the MOSFET case. Regardless of which transistor type used, the switching losses are around 20 % of the total losses at around 25 kHz. With DuC an almost constant switching frequency is used over the full voltage range compared to FM were the switching frequency increases by 13 %. Additionally a reduction of capacitive snubbers is achieved with DuC.

  • 22.
    Tolstoy, Georg
    et al.
    KTH.
    Ranstad, P.
    Colmenares, Juan
    KTH, Skolan för elektro- och systemteknik (EES), Elkraftteknik.
    Giezendanner, F.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Experimental evaluation of SiC BJTs and SiC MOSFETs in a series-loaded resonant converter2015Ingår i: Power Electronics and Applications (EPE’15 ECCE-Europe), 2015 17th European Conference on, IEEE , 2015, s. 1-9Konferensbidrag (Refereegranskat)
    Abstract [en]

    SiC devices such as MOSFETs and BJTs have proven themselves to be contenders to improve the efficiency of resonant converters. The losses of the full-bridge inverter are well below 1% of the rated power at switching frequencies up to 200 kHz, making it possible to reach even higher frequencies. An experimental setup is built and two different full-bridge inverters are tested. One is built with SiC MOSFETs and no additional anti-parallel diodes and one with SiC BJTs and SiC Schottky diodes.

  • 23.
    Tolstoy, Georg
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ranstad, Per
    Colmenares, Juan
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Giezendanner, Florian
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Dual control used in series-loaded resonant converter with SiC devicesManuskript (preprint) (Övrigt vetenskapligt)
  • 24.
    Tolstoy, Georg
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ranstad, Per
    Colmenares, Juan
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Giezendanner, Florian
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Experimental evaluation of SiC BJT and SiC MOSFET in a series resonantconverterManuskript (preprint) (Övrigt vetenskapligt)
  • 25.
    Tolstoy, Georg
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ranstad, Per
    Colmenares, Juan
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Giezendanner, Florian
    Rabkowski, Jacek
    Warsaw University of Technology, Poland.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    An experimental analysis on how the dead-time of SiC BJT and SiC MOSFET impacts the losses in a high-frequency resonant converter2014Ingår i: 2014 16th European Conference on Power Electronics and Applications, EPE-ECCE Europe 2014, IEEE conference proceedings, 2014, s. 6911042-Konferensbidrag (Refereegranskat)
    Abstract [en]

    Active control of the dead-time in a SLR converter is in this paper shown to be of great importance. The efficiency of the full-bridge will increase if the dead-time control is made in the right way. Different control algorithms are shown to work well for different power switches. For the SiC MOSFET and the SiC BJT the control algorithms are tested experimentally.

  • 26.
    Tolstoy, Georg
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Ranstad, Per
    Colmenares, Juan
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Peftitsis, Dimosthenis
    Giezendanner, Florian
    Rabkowski, Jacek
    Warsaw University of Technology, Poland.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    An experimental analysis on how the dead-time of SiC BJT and SiC MOSFET impacts the losses in a high-frequency resonant converterManuskript (preprint) (Övrigt vetenskapligt)
  • 27.
    Tolstoy, Georg
    et al.
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Wallmark, Oskar
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Norrga, Staffan
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Nee, Hans-Peter
    KTH, Skolan för elektro- och systemteknik (EES), Elektrisk energiomvandling.
    Larsson, B.
    Elimination of vector changes due to sector changes with DTC*2015Ingår i: EPE Journal: European Power Electronics and Drives Journal, ISSN 0939-8368, Vol. 25, nr 4, s. 11-16Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In this paper it has been investigated if there is a possibility to reduce the switching frequency for a two-level inverter by improving the direct torque control (DTC) algorithm by adding a non-switching condition when a new sector is entered. It is believed that the DTC switching table can be improved by adding a non-switching condition when sector change occurs. This will reduce the number of switching actions by up to 12 per electrical rotation without interfering with the electrical machine performance.

1 - 27 av 27
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