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Träfflista för sökning "WFRF:(Nee Hans Peter 1963 ) srt2:(2015-2019)"

Sökning: WFRF:(Nee Hans Peter 1963 ) > (2015-2019)

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1.
  • Risseh, Arash, 1980-, et al. (författare)
  • Design of a Thermoelectric Generator for Waste Heat Recovery Application on a Drivable Heavy Duty Vehicle
  • 2017
  • Ingår i: SAE International Journal of Commercial Vehicles. - : SAE International. - 1946-391X .- 1946-3928. ; 10:1, s. 26-44
  • Tidskriftsartikel (refereegranskat)abstract
    • The European Union’s 2020 target aims to be producing 20 % of its energy from renewable sources by 2020, to achieve a 20 % reduction in greenhouse gas emissions and a 20 % improvement in energy efficiency compared to 1990 levels. To reach these goals, the energy consumption has to decrease which results in reduction of the emissions. The transport sector is the second largest energy consumer in the EU, responsible for 25 % of the emissions of greenhouse gases caused by the low efficiency (<40 %) of combustion engines. Much work has been done to improve that efficiency but there is still a large amount of fuel energy that converts to heat and escapes to the ambient atmosphere through the exhaust system. Taking advantage of thermoelectricity, the heat can be recovered, improving the fuel economy. A thermoelectric generator (TEG) consists of a number of thermoelectric elements, which advantageously can be built into modules, arranged thermally and electrically, in a way such that the highest possible thermal power can be converted into electrical power. In a unique waste heat recovery (WHR) project, five international companies and research institutes cooperated and equipped a fully drivable Scania prototype truck with two TEGs. The entire system, from the heat transfer in the exchangers to the electrical power system, was simulated, built and evaluated. The primary experimental results showed that approximately 1 kW electrical power could be generated from the heat energy. In this paper the entire system from design to experimental results is presented.
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3.
  • Ahmed, Noman, et al. (författare)
  • Performance of the modular multilevel converter with redundant submodules
  • 2015
  • Ingår i: IECON 2015 - 41st Annual Conference of the IEEE Industrial Electronics Society. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781479917624 ; , s. 3922-3927
  • Konferensbidrag (refereegranskat)abstract
    • The modular multilevel converter (MMC) is the state-of-the-art voltage-source converter (VSC) topology used for various power-conversion applications. In the MMC, submodule failures can occur due to various reasons. Therefore, additional submodules called the redundant submodules are included in the arms of the MMC to fulfill the fault-safe operation requirement. The performance of the MMC with redundant submodules has not been widely covered in the published literature. This paper investigates the performance of the MMC with redundant submodules in the arms. Two different control strategies are used and compared for integrating redundant submodules. The response of the MMC to a submodule failure for the two strategies is also studied. Moreover, the operation of the MMC with redundant submodules is validated experimentally using the converter prototype in the laboratory.
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4.
  • Augustin, Tim, et al. (författare)
  • Advanced Test Circuit for DC Circuit Breakers
  • 2018
  • Ingår i: 20th European Conference on Power Electronics and Applications (EPE'18 ECCE EUROPE).
  • Konferensbidrag (refereegranskat)abstract
    • In future HVDC systems, many DC circuit breakers (DCCBs) will be required. In this paper, an advanced test circuit for DCCBs is described. A DC source is combined with a capacitor bank. In contrast to other test circuits, the proposed test circuit allows to replicate constant DC and temporary faults. In addition to conventional faults, this enables testing of auto-reclosing, proactive commutation, and complex test sequences combining all of these modes. The test circuit is easy to setup and also suitable for smaller research facilities. Experimental results from a down-scaled mock-up are included to demonstrate the capabilities of the test circuit.
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5.
  • Augustin, Tim, et al. (författare)
  • Modelling of HVDC breakers for HVDC grid simulations
  • 2017
  • Ingår i: IET Conference Publications. - : Institution of Engineering and Technology.
  • Konferensbidrag (refereegranskat)abstract
    • This paper deals with the modelling of high-voltage direct current (HVDC) breakers in PSCAD. The models are aimed at HVDC grid simulation and are kept as simple as possible. An overview is given over recently proposed HVDC breaker concepts. Assumptions and simplifications are explained as well. The main result is that even these simplified models are too detailed for grid simulations. The reason for this is that from a grid perpective the only thing that matters is when the metal-oxide varistor is inserted. The models can be used to estimate interruption times.
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6.
  • Augustin, Tim, et al. (författare)
  • System Design of Fast Actuator for Vacuum Interrupter in DC Applications
  • 2018
  • Ingår i: 2018 28th International Symposium on Discharges and Electrical Insulation in Vacuum (ISDEIV). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538643730 ; , s. 527-530
  • Konferensbidrag (refereegranskat)abstract
    • One of the major challenges of DC circuit breakers is the required fast mechanical actuator. In this paper, a Thomson coil actuator system for a vacuum interrupter is designed. Active damping is used to decelerate the moving contacts. Challenges are discussed, especially concerning the power supply needed for the Thomson coil actuator. The design philosophy is explained and FEM simulation results are presented. The results indicate that a wide range of combinations of drive circuit capacitance and voltage fulfill the requirements for armature acceleration. However, active damping requires a very careful selection of drive circuit voltage and timing of applied damping.
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7.
  • Augustin, Tim, et al. (författare)
  • Transient Behaviour of VSC-HVDC Links with DC Breakers Under Faults
  • 2017
  • Ingår i: 2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE EUROPE). - : Institute of Electrical and Electronics Engineers (IEEE). - 9789075815276
  • Konferensbidrag (refereegranskat)abstract
    • In future high-voltage direct current (HVDC) systems, a large number of HVDC breakers will be required.In this paper, the influence of HVDC breakers on the transient performance of point-to-point HVDC links in both asymmetrical and symmetrical monopolar configuration with half-bridge modular multilevel converters is studied with simulations in PSCAD. As HVDC breakers, the active resonant breaker and ABB’s hybrid breaker are considered. The analyzed scenarios include DC line faults, DC bus faults, and AC faults between the converter and the transformer. The highest DC breaking capability is required during DC line faults in the asymmetric and symmetric monopole. The converter stress is highest for DC bus faults and unbalanced converter AC faults in the asymmetric monopole and for DC bus pole-to-pole faults in the symmetric monopole. During DC pole-to-ground faults in the symmetric monopole, the HVDC breaker combined with DC side arrestors yields the lowest overvoltage stress on the cable of the healthy pole. The fault current shapes depend strongly on the interaction of the converter and the travelling waves on the lines, and differ from the fault current shapes in typical HVDC breaker test circuits. Furthermore, the active resonant breaker and the ABB hybrid breaker perform similarly in the used benchmarks due to the very fast DC line fault detection.
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8.
  • Bakas, Panagiotis, et al. (författare)
  • Design considerations and comparison of hybrid line-commutated and cascaded full-bridge converters with reactive-power compensation and active filtering capabilities
  • 2019
  • Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
    • This paper compares two hybrid topologies that combine the line-commutated converter (LCC) with cascaded full-bridge (FB) converters. The latter are utilized for compensating the reactive power and filtering the current harmonics of the LCC. The method that was developed for dimensioning these hybrid topologies is presented in detail. This method is utilized for calculating the arm voltage and current waveforms, which are used to estimate other important quantities, such as conduction losses and energy variations. Finally, the studied converters are compared in terms of voltage/current ratings, semiconductor requirements, conduction losses, and energy variations.
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9.
  • Bakas, Panagiotis, et al. (författare)
  • Hybrid alternate-common-arm converter with director thyristors - Impact of commutation time on the active-power capability
  • 2019
  • Ingår i: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe. - Genova, Italy : Institute of Electrical and Electronics Engineers Inc.. - 9789075815313 - 9781728123615
  • Konferensbidrag (refereegranskat)abstract
    • This paper investigates the impact of the thyristor commutation time on the peak currents and the active-power capability of the hybrid alternate-common-arm converter (HACC). This converter employs director thyristors for the alternate connection of a common arm in parallel to the main arms. The parallel connection enables current sharing among the arms, which allows the HACC to transfer higher output power without increasing the peak arm current. It is shown that the active-power capability of the HACC is doubled for a certain current-sharing factor, which, however, is altered by the thyristor commutation time. Therefore, the impact of the commutation time on the active-power capability of the HACC is investigated theoretically. Finally, this analysis is verified by simulation results.
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10.
  • Bakas, Panagiotis, et al. (författare)
  • Hybrid Converter With Alternate Common Arm and Director Thyristors for High-Power Capability
  • 2018
  • Ingår i: 2018 20th European Conference on Power Electronics and Applications (EPE’18 ECCE Europe).
  • Konferensbidrag (refereegranskat)abstract
    • This paper presents the basic operating principles of a new hybrid converter that combines thyristors and full-bridge (FB) arms for achieving high active-power capability. This converter consists of a modular multilevel converter (MMC) equipped with additional common arms, which alternate between the upper and lower dc poles. This alternation is achieved by the thyristors that are utilized as director switches and allow the parallel connection of the common arms and the arms of the MMC. The main contributions of this paper are the analysis of the operating principles, the simulation verification of the functionality of the proposed converter, and the comparison of the latter with the full-bridge modular multilevel converter (FB-MMC).
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11.
  • Bakas, Panagiotis (författare)
  • Hybrid Converters for HVDC Transmission
  • 2019
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The line-commutated converter (LCC) and the voltage-source converter (VSC) are the two main converter technologies utilized in high-voltage direct current (HVDC) transmission applications. Depending on the application requirements, one technology might be more advantageous than the other. On the one hand, the LCC features technological maturity, high efficiency, and high power-transfer capability, but it lacks the ability to independently control active and reactive power and to ride through ac faults. On the other hand, the VSC overcomes the shortcomings of the LCC and offers more functionality, as it features the ability to independently control active and reactive power, ac-fault ride through capability, black-start capability, and superior harmonic performance. Yet, it is less mature, less efficient, and has lower power-transfer capability than the LCC. Thus, the combination of the LCC and the VSC topologies could yield hybrid converters that leverage the complementary characteristics of both technologies and thus are optimized for HVDC applications. Therefore, the main objective of this thesis is to investigate existing and derive new hybrid converters that combine the complementary characteristics of the LCC and VSC technologies.The hybrid converters investigated in this thesis are divided in two main categories, namely: (a) current-source; and (b) voltage-source hybrid converters. The former category includes hybrid converters that are based on the LCC structure and utilize a VSC part either for compensating the reactive power consumed by the LCC, or for active filtering of the LCC current harmonics, or for independently controlling active and reactive power, or for achieving a combination of these functionalities. Four different current-source hybrid converters have been investigated and compared in terms of functionality, conduction losses, and semiconductor requirements.The second category includes more complex circuits that combine thyristors and modular VSC elements in ways that enable these hybrid converters to operate as VSCs and to achieve high active-power capability. Two new voltage-source hybrid converters are analyzed and compared in terms of active-power capability, semiconductor requirements, and controllability. This study reveals that the hybrid alternate-common-arm converter (HACC) is the most interesting circuit; thus, an in-depth analysis is performed for this converter. The theoretical analysis shows that, under certain operating conditions, the HACC can transfer twice the active power of the full-bridge modular multilevel converter (FB-MMC) with lower semiconductor rating per unit of active power. Yet, if the total commutation time of the thyristors and/or the power angle are increased beyond certain values, the active-power capability of the HACC is reduced. Finally, simulation and experimental results are provided in order to verify the theoretical analysis and prove the feasibility of the HACC.
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12.
  • Ciftci, Baris, 1987-, et al. (författare)
  • A Proposal for Wireless Control of Submodules in Modular Multilevel Converters
  • 2018
  • Konferensbidrag (refereegranskat)abstract
    • The modular multilevel converter is one of the most preferred converters for high-power conversion applications. Wireless control of the submodules can contribute to its evolution by lowering the material and labor costs of cabling and by increasing the availability of the converter. However, wireless control leads to many challenges for the control and modulation of the converter as well as for proper low-latency high-reliability communication. This paper investigates the tolerable asynchronism between phase-shifted carriers used in modulation from a wireless control point of view and proposes a control method along with communication protocol for wireless control. The functionality of the proposed method is validated by computer simulations in steady state.
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13.
  • Ciftci, Baris, et al. (författare)
  • Simple Distributed Control for Modular Multilevel Converters
  • 2019
  • Ingår i: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe. - Brussels : European Power Electronics and Drives Association. - 9789075815306
  • Konferensbidrag (refereegranskat)abstract
    • The central control of MMC becomes demanding in computation power and communication bandwidth as the number of submodules increase. Distributed control methods can overcome these bottlenecks. In this paper, a simple distributed control method together with synchronization of modulation carriers in the submodules is presented. The proposal is implemented on a lab-scale MMC with asynchronous-serial communication on a star network between the central and local controllers. It is shown that the proposed control method works satisfactorily in the steady state. The method can be applied as is to MMCs with any number of submodules per arm.
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14.
  • Heinig, Stefanie, et al. (författare)
  • Implications of Capacitor Voltage Imbalance on the Operation of the Semi-Full-Bridge Submodule
  • 2019
  • Ingår i: IEEE transactions on power electronics. - : Institute of Electrical and Electronics Engineers (IEEE). - 0885-8993 .- 1941-0107. ; 34:10, s. 9520-9535
  • Tidskriftsartikel (refereegranskat)abstract
    • Future meshed high-voltage direct current grids require modular multilevel converters with extended functionality. One of the most interesting new submodule topologies is the semi-full-bridge because it enables efficient handling of DC-side short circuits while having reduced power losses compared to an implementation with full-bridge submodules. However, the semi-full-bridge submodule requires the parallel connection of capacitors during normal operation which can cause a high redistribution current in case the voltages of the two submodule capacitors are not equal. The maximum voltage difference and resulting redistribution current have been studied analytically, by means of simulations and in a full-scale standalone submodule laboratory setup. The most critical parameter is the capacitance mismatch between the two capacitors. The experimental results from the full-scale prototype show that the redistribution current peaks at 500A if the voltage difference is 10V before paralleling and increases to 2500A if the difference is 40V. However, neglecting very unlikely cases, the maximum voltage difference predicted by simulations is not higher than 20-30V for the considered case. Among other measures, a balancing controller is proposed which reduces the voltage difference safely if a certain maximum value is surpassed. The operating principle of the controller is described in detail and verified experimentally on a down-scaled submodule within a modular multilevel converter prototype. It can be concluded that excessively high redistribution currents can be prevented. Consequently, they are no obstacle for using the semi-full-bridge submodule in future HVDC converters.
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15.
  • Heinig, Stefanie, et al. (författare)
  • Reduction of Switching Frequency for the Semi-Full-Bridge Submodule Using Alternative Bypass States
  • 2018
  • Ingår i: 2018 20TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE'18 ECCE EUROPE). - : IEEE. - 9789075815283
  • Konferensbidrag (refereegranskat)abstract
    • As regards modular multilevel converter submodules, a different number of switches may be involved in the transitions between voltage levels depending on the submodule type and choice of switching states. In this paper, an investigation of the average switching frequency associated with different choices of bypass states is performed for the semi-full-bridge submodule. Theoretical considerations and simulation results show that the average switching frequency per device can be halved by using the proposed alternative bypass state. Moreover, the switching losses can be reduced by up to 60%. Finally, a comparative study with the full-bridge submodule has been conducted.
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16.
  • Heuvelmans, Matthijs (författare)
  • Cost-effective Cells for High-power Modular Multilevel Converters
  • 2018
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • The modular multilevel converter (MMC) topology was introduced in 2003and has since been receiving considerable attention from industry and academia.Notable benefits compared to two- or three-level voltage source convertersare its scalability, low switching losses, low output filter requirementsand ease of adding redundancy combined with fail-safe operation. There area number of disadvantages, such as the use of large bus capacitors and complexityof control. However, with currently predominant switch technology forhigh power levels, which are bipolar silicon devices, the benefits outweigh thedisadvantages. The use of integrated gate commutated thyristors (IGCTs) inan MMC is an attractive option compared to using IGBTs due to their robustnessand low conduction losses. Switching losses are of lesser importance,but not negligible.The objectives of this work are to contribute to a reduction in equipmentcost and to a decrease power loss in HVDC and STATCOM installations.The approach to achieve those objectives is by using the auxiliary resonantcommutated pole topology in IGCT-based MMC. In case thyristors are usedas auxiliary switches, the total amount of needed hardware does not differsignificantly from a hard-switched solution which needs a di/dt reactor and asnubber. The reduced switching losses in the main switches (IGCTs) lead toan efficiency increase, but also to the possibility of using higher-voltage devicesthat would otherwise be impracticable. This in turn can lead to a reduction inhardware cost due to a lower number of cells and lower conduction losses. Inaddition, the improved switching conditions allow for an increase in turn-offcurrent capability. Practical aspects that are also treated in this work are theuse of snubber circuits for the auxiliary switch, and the behaviour under ashoot-through. The latter aspect is essential for practical use in high-powerMMCs. In this work a fault-tolerant soft-switching cell is presented, whichallows for a current limiting series inductance between the main switches andthe dc-bus capacitor without causing a problematic voltage overshoot.
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17.
  • Jacobs, Keijo, et al. (författare)
  • Dissipation Loop for Shoot-Through Faults in HVDC Converter Cells
  • 2018
  • Ingår i: 2018 INTERNATIONAL POWER ELECTRONICS CONFERENCE (IPEC-NIIGATA 2018 -ECCE ASIA). - : Institute of Electrical and Electronics Engineers (IEEE). - 9784886864055 ; , s. 3292-3298
  • Konferensbidrag (refereegranskat)abstract
    • Converter cells for HVDC applications store large amounts of energy. This energy might be dissipated in a very short time in case of a shoot-through fault. Measures to avoid shoot-through or handle the extreme currents during a fault and prevent damage from neighboring components are essential to ensure a continued operation of the converter. With future high-voltage silicon carbide semiconductors, cell voltages can be increased leading to higher stored energy per cell. In cells with thyristor-based semiconductors, e.g. IGCTs, a di/dt reactor may have to be employed. This paper presents a method to handle the dissipated energy during shoot-through which makes use of the inherently needed di/dt reactor. The majority of the stored energy in the cell can be dissipated in a dedicated discharge loop formed by the reactor and an antiparallel bypass thyristor. After diverting the fault current into the dissipation loop, there is no current through any other component of the cell.
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18.
  • Jacobs, Keijo, et al. (författare)
  • Low Loss Submodule Cluster for Modular Multilevel Converters Suitable for Implementation with SiC MOSFETs
  • 2019
  • Ingår i: Proceedings IEEE Energy Conversion Congress and Exposition 2019. - : IEEE. - 9781728103952 - 9781728103969
  • Konferensbidrag (refereegranskat)abstract
    • In this paper, a novel submodule cluster topologyfor modular multilevel converters is proposed. The cluster iscomposed of an arbitrary amount of submodule segments. Dependingon the amount of capacitors in the cluster, the converterconduction losses can be reduced significantly. The topologyenables electronic protection against explosion, thus, reducingthe requirements for submodule bypass equipment. Implicationsfor the converter operation and functionality are investigated anda wireless control scheme is proposed.
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19.
  • Jacobs, Keijo, et al. (författare)
  • MMC Converter Cells Employing Ultrahigh-Voltage SiC Bipolar Power Semiconductors
  • 2017
  • Ingår i: 2017 19th European Conference on Power Electronics and Applications (EPE'17 ECCE EUROPE). - : Institute of Electrical and Electronics Engineers (IEEE). - 9789075815276
  • Konferensbidrag (refereegranskat)abstract
    • This paper investigates the benefits of using high-voltage converter cells for transmission applications. These cells employ ultrahigh-voltage SiC bipolar power semiconductors, which are optimized for low conduction losses. The Modular Multilevel Converter with half-bridge cells is used as a test case. The results indicate a reduction of converter volume and complexity, while maintaining low losses and harmonic performance.
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20.
  • Johannesson, Daniel, et al. (författare)
  • TCAD Model Calibration of High Voltage 4H-SiC Bipolar Junction Transistors
  • 2019
  • Ingår i: Materials Science Forum. - : Trans Tech Publications, Ltd.. ; , s. 670-673
  • Konferensbidrag (refereegranskat)abstract
    • In this project, a Technology CAD (TCAD) model has been calibrated and verified against experimental data of a 15 kV silicon carbide (SiC) bipolar junction transistor (BJT). The device structure of the high voltage BJT has been implemented in the Synopsys Sentaurus TCAD simulation platform and design of experiment simulations have been performed to  extract and fine-tune device parameters and 4H-SiC material parameters to accurately reflect the 15 kV SiC BJT experimental results. The set of calibrated TCAD parameters may serve as a base for further investigations of various SiC device design and device operation in electrical circuits.
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21.
  • Lindahl, Martin, et al. (författare)
  • Silicon Carbide MOSFET Traction Inverter Operated in the Stockholm Metro System Demonstrating Customer Values
  • 2018
  • Ingår i: 2018 IEEE VEHICLE POWER AND PROPULSION CONFERENCE (VPPC). - : IEEE. - 9781538662038
  • Konferensbidrag (refereegranskat)abstract
    • For the first time results are reported in literature of a successful field test using a silicon carbide (SiC) metal-oxide semi-conductor field-effect transistor (MOSFET) traction inverter operated in the field. The metro train has been operated over a period of 3 months on the Green Line in the Stockholm metro system. Increased traction converter power density with a volume reduction of 51 % as well as a weight reduction of 22 % have been achieved. Lower power losses allow the use of car motion cooling. From complementing measurements in the laboratory of silicon and SiC in the same power device package with varying switching frequencies considerably lower SiC temperatures can be reported.
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22.
  • Lindahl, Martin, Doktorand, 1985-, et al. (författare)
  • Threshold for induction motor terminal transient peak voltage with fast switching inverters
  • 2019
  • Ingår i: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe. - : Institute of Electrical and Electronics Engineers Inc.. - 9789075815313
  • Konferensbidrag (refereegranskat)abstract
    • Concerns have been raised that motor voltages might be very high if the fast switching characteristics of silicon carbide (SiC) are to be utilized. For this reason, the magnitude of the terminal voltage of an induction motor is investigated when fed from a fast switching SiC inverter through a long cable. It is found that the main insulation demand for the SiC case is only increased by 5 % compared to the silicon insulated-gate bipolar transistor (IGBT) case. This indicates that additional filters may not be necessary in applications with long cables where silicon IGBTs are replaced by fast switching SiC power semiconductors.
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23.
  • Modeer, Tomas, 1979-, et al. (författare)
  • High-Voltage Tapped-Inductor Buck Converter Utilizing an Autonomous High-Side Switch
  • 2015
  • Ingår i: IEEE Transactions on Industrial Electronics. - : IEEE Press. - 0278-0046 .- 1557-9948. ; 62:5, s. 2868-2878
  • Tidskriftsartikel (refereegranskat)abstract
    • A high-voltage tapped-inductor buck converter utilizing a novel autonomous high-voltage valve is presented in this paper. Its application as auxiliary power supply for high-power cascaded-converter submodules is discussed, followed by a presentation of the most challenging problems in designing a low-power high-voltage step-down converter. The TI-buck converter topology is analyzed, which together with the novel autonomous high-voltage valve overcomes most of the problems. Analytical expressions describing the operation as well as circuit simulations are presented. Finally, an experimental evaluation of a 3-kV 70-W prototype converter utilizing the proposed autonomous high-voltage valve with series-connected super-junction MOSFETs is presented.
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24.
  • Nikouei Harnefors, Mojgan, et al. (författare)
  • A highly integrated electric drive system for tomorrow's EVs and HEVs
  • 2018
  • Ingår i: Proceedings - 2017 IEEE Southern Power Electronics Conference, SPEC 2017. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781509064250 ; , s. 1-5
  • Konferensbidrag (refereegranskat)abstract
    • This paper presents an ultra-compact integrated electric drive prototype. The prototype illustrates the integration of a fractional slot concentrated winding (FSCW) electric motor, a stacked polyphase bridges (SPB) converter, the control boards, and the water cooling plates into a common housing. This integrated prototype offers a high potential of compactness and cost reduction for electric and hybrid electric vehicles.
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25.
  • Nikouie, Mojgan (författare)
  • Design, Construction and Evaluation of a StackedPolyphase Bridges Converter for Integrated ElectricDrive Systems in Automotive ApplicationsMOJGAN NIKOUIEDoctoral ThesisStockholm, Sweden
  • 2019
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • This thesis presents a new concept for integration of the electricdrive system, specifically for electric and hybrid electric vehicle applications.The topology introduces an integration between the so-calledstacked polyphase bridges (SPB) converter and fractional-slot concentratedpermanent-magnet synchronous machine. The SPB converter iscomprised of an arbitrary number of submodules that are connected inseries to a dc-source voltage. A very compact integrated electric drivesystem is gained by the integration. Several advantages are potentiallygained from the concept, such as considerably shortening the powercables interconnecting the converter with the machine and as well asreduction in terms of electromagnetic interference, weight, and size.The principal focus of the thesis is on the design, construction, andcontrol of the SPB converter. Three different generations for the SPBconverter, all with four submodules, have been developed within theproject. In the first two generations, a submodule consists of a two-layerprinted circuit board (PCB) including both power and control circuits,whereas in the third generation, each submodule has separate powerand control boards. The power circuit is a conventional two-level threephaseconverter. In the third generation, the power PCBs can handlean rms current of 100 A and a dc-link voltage of 100 V.Along with the design of the converter, control algorithms have beendeveloped. A conventional proportional–integral (PI) current controlleris implemented on the microprocessor of each control board, on whichouter control loops are added. One important contribution concerningthe control is the stability analysis and balancing controller designresulting thereof. Since the submodules are series connected to the dcsourcevoltage, it is essential to ensure that the total voltage is sharedequally among the submodules.Secondly, a study of the SPB converter under fault is made. It is assumedthat one submodule is facing a short- or open-circuited powertransistor and the behavior of the converter is studied. A proposal fora safe way of short circuiting the faulty submodule is presented.Finally, torque ripple minimization is discussed. It is shown that usingan estimator for the flux linkage harmonics in the machine as well asadding a resonant part to the PI current controller can be an efficientmethod to suppress the ripple.
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26.
  • Risseh, Arash Edvin, et al. (författare)
  • Fast Switching Planar Power Module With SiC MOSFETs and Ultra-low Parasitic Inductance
  • 2018
  • Ingår i: 2018 INTERNATIONAL POWER ELECTRONICS CONFERENCE (IPEC-NIIGATA 2018 -ECCE ASIA). - : Institute of Electrical and Electronics Engineers (IEEE). - 9784886864055 ; , s. 2732-2737
  • Konferensbidrag (refereegranskat)abstract
    • Parasitic inductances caused by the package of semiconductor devices in power converters, are limiting the switching speed and giving rise to higher switching losses than necessary. In this study a half-bridge planar power module with Silicon Carbide (SiC) MOSFET bare dies was designed and manufactured for ultra-low parasitic inductance. The circuit structure was simulated and the parasitic inductances were extracted from ANSYS-Q3D. The values were then fed into LT-Spice to simulate the electrical behavior of the half-bridge. The experimental and simulation results were compared to each other and were used to adjust and easily extend the simulation model with additional MOSFETs for higher current capability. It was shown that the proposed planar module, with four parallel SiC MOSFETs at each position, is able to switch 600V and 400A during 40 and 17ns with E-ON and E-OFF equal to 3.1 and 1.3mJ, respectively. Moreover, unlike the commercial modules, this design allows double-sided cooling to extract the generated heat from the device, resulting in lower operating temperature.
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27.
  • Risseh, Arash Edvin, et al. (författare)
  • Realization of a Planar Power Circuit With Silicon Carbide MOSFETs on Printed Circuit Board
  • 2018
  • Ingår i: SPEEDAM 2018 - Proceedings: International Symposium on Power Electronics, Electrical Drives, Automation and Motion. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781538649411 ; , s. 1079-1083
  • Konferensbidrag (refereegranskat)abstract
    • Silicon Carbide (SiC) MOSFETs offer excellent properties as switches in power converters. However, the package of the device is an issue that prevents utilizing the advantages of SiC, as for instance fast switching speed. The packages of currently available SiC devices are the same as those previously used for silicon devices with moderate electrical and thermal characteristics resulting in accelerated aging and reliability issues. Moreover, the parasitic inductance caused by the package, limits the switching time and operating frequency. By excluding the package, the parasitic inductances will be eliminated to a large extent. In this study, the procedure of manufacturing a half-bridge planar power module, using four SiC MOSFET bare dies and PCB, is described. According to simulations, the parasitic inductance Lstray of the structure is approximately 96 % lower than most commercial half-bridge modules. It is also shown that double-side cooling can be employed for the proposed module if substrates with low thermal resistance are employed.
  •  
28.
  • Risseh, Arash Edvin, 1980- (författare)
  • Waste-heat Recovery Using Thermoelectricity and Silicon Carbide Power Electronics
  • 2019
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • Energy consumption in the world has increased continuously due to a growing population and increased energy consumption per capita. Moreover, the largest part of consumed energy still comes from fossil sources which in 2016 was more than 130 PWh. In order to minimize the greenhouse effect and meet the climate targets, the world's energy consumption must be greatly reduced and the energy also has to be used more efficiently. Due to the low efficiency of internal combustion engines in vehicles, the transport sector is the second largest source of greenhouse gas emissions, responsible for 20 % of the total CO2 emissions in the EU. In this work the electrical arrangement and power conditioning system suitable for waste heat recovery, using thermoelectric energy conversion in heavy duty vehicles, are investigated. Without a proper power conditioning system, the recovered power from a thermoelectric generator (TEG) disappears in form of Joule-losses. High-efficiency inter-leaved step-down converter with 98 % efficiency was developed and tested on a real-scale prototype truck, equipped with two TEGs. In addition, a strategy was required for the connection of thermoelectric modules (TEM) in the TEGs. A TEG may consist of several hundred TEMs and without a suitable connection, the thermal losses can be so high that the net power, recovered by the TEG is insignificant. In the worst case this can lead to an even higher fuel consumption. Moreover, the possibility to employ silicon carbide (SiC) metal oxide semiconductor field-effect transistor (MOSFET), which is a voltage-controlled and normally-OFF device, with high electric field strength, in such a low-voltage application (100-200 V), was investigated. Due to the high blocking voltage and power density, SiC MOSFETs are expected to replace silicon (Si) insulated gate bipolar transistors (IGBTs) in power converters. However, in low-voltage applications where Si MOSFETs are usually used, there have not been any obvious advantages to use SiC MOSFETs as a substitute for Si MOSFETs. Here, it is shown that SiC MOSFETs can advantageously be used in low-voltage applications. SiC MOSFETs have exceptional properties that nevertheless are fully utilized today. The packages of currently available SiC devices are the same as those previously used for Si devices, with moderate electrical and thermal characteristics. This results in slow switching speed, unnecessary losses. A half-bridge planar module using SiC MOSFET bare dies were designed, manufactured and tested. It was shown that a module with the same structure and 8 SiC MOSFETs can be manufactured with ultra-low parasitic inductances. The total switching energy was found to be 4.4 mJ which is approx. 63 % lower than commercially available modules.This thesis can be divided into three parts. In the first part, thermoelectricity is introduced and an introduction of SiC MOSFETs and its applications are given. In the second part, the results of waste heat recovery using TEG and its electrical arrangement in a Scania truck are presented. In this part, also the output power and the efficiency of the converter, using Si and SiC MOSFETs, are discussed. In the final part, the proposed planar power module with SiC MOSFET bare dies, its benefits such as reduced switching losses and double-sided cooling, are presented.
  •  
29.
  • Risseh, Arash, 1980-, et al. (författare)
  • Electrical performance of directly attached SiC power MOSFET bare dies in a half-bridge configuration
  • 2017
  • Ingår i: 2017 IEEE 3rd International Future Energy Electronics Conference and ECCE Asia, IFEEC - ECCE Asia 2017. - Taiwan : Institute of Electrical and Electronics Engineers (IEEE). - 9781509051571 ; , s. 417-421
  • Konferensbidrag (refereegranskat)abstract
    • The demand for high-efficiency power converters is increasing continuously. The switching losses are typically significant in power converters. During the switching time, the component is exposed to a considerable voltage and current causing power loss. The switching time is limited by parasitic inductance produced by traces and interconnections inside and outside the package of a device. Moreover, the parasitic inductances at the input-terminal together with the Miller capacitance generate oscillations causing instability and additional losses. In order to eliminate the package parasitic inductance, four 1.2kV SiC-MOSFET bare dies, two in parallel in each position, were directly attached to a PCB sandwich designed as a half bridge. The obtained structure forms a planar power module. From ANSYS Q3D simulations it was found that the parasitic inductance between drain and source for each transistor in the proposed planar module could be reduced 92 % compared to a TO247 package. The planar module was also tested as a dc-dc converter. Switching waveforms from these experiments are also presented
  •  
30.
  • Risseh, Arash, 1980-, et al. (författare)
  • Electrical Power Conditioning System for Thermoelectric Waste Heat Recovery in Commercial Vehicles
  • 2018
  • Ingår i: IEEE TRANSACTIONS ON TRANSPORTATION ELECTRIFICATION. - : IEEE. - 2332-7782. ; :99
  • Tidskriftsartikel (refereegranskat)abstract
    • A considerable part of the fuel energy in vehicles never reaches the wheels and entirely converts to waste heat. In a heavy duty vehicle (HDV) the heat power that escapes from the exhaust system may reach 170 kW. The waste heat can be converted into useful electrical power using thermoelectric generator (TEG). During the last decades, many studies on the electrical power conditioning system of TEGs have been conducted. However, there is a lack of studies evaluating the electrical instrumentation, the impact of the converter-efficiency, and the TEG arrangement on a real large-scale TEG on-boarda drivable vehicle. In this study, the most important parameters for designing electrical power conditioning systems for two TEGs, developed for a real-scale HDV as well as experimental results demonstrating the recovered electrical power, are presented. Eight synchronous inter-leaved step-down converters with 98 % efficiency with perturb and observe maximum power point tracker was developed and tested for this purpose. The power conditioning system was communicating with the on-board computers through the controller area network and reported the status of the TEGs and the recovered electrical power. The maximum recovered electrical power from the TEGs reached 1 kW which was transmitted to the electrical system of the vehicle, relieving the internal combustion engine.
  •  
31.
  • Sadik, Diane, 1988-, et al. (författare)
  • Effect of Parasitic Inductance in a Soft-Switching SiC Power Converter
  • 2018
  • Ingår i: 2018 20TH EUROPEAN CONFERENCE ON POWER ELECTRONICS AND APPLICATIONS (EPE'18 ECCE EUROPE). - : IEEE. - 9789075815283
  • Konferensbidrag (refereegranskat)abstract
    • Wide Bandgap power semiconductors such as SiC MOSFETs, have enabled compact and highly efficient power converters operated at higher frequencies. However, parasitic inductance of the package may significantly increase power losses and limit the operation. This paper aims to quantify experimentally these losses in a soft-switching converter. A "removable" stray inductance is implemented in a setup consisting of discrete SiC MOSFET units. Thus, the power loss of the transistors with and without stray inductance can be compared. Similarly slower switching speeds are also implemented to fully emulate a 62-mm module. The power loss induced by the package can thus be evaluated.
  •  
32.
  • Sadik, Diane, 1988-, et al. (författare)
  • Effect of Parasitic Inductance in a Soft-Switching SiC Power Converter Topics : 1 b: New Materials and Active Devices 7b: High-voltage DC Power Supplies (U)
  • 2018
  • Ingår i: 2018 20th European Conference on Power Electronics and Applications, EPE 2018 ECCE Europe. - : Institute of Electrical and Electronics Engineers Inc.. - 9789075815283
  • Konferensbidrag (refereegranskat)abstract
    • Wide Bandgap power semiconductors such as SiC MOSFETs, have enabled compact and highly efficient power converters operated at higher frequencies. However, parasitic inductance of the package may significantly increase power losses and limit the operation. This paper aims to quantify experimentally these losses in a soft-switching converter. A 'removable' stray inductance is implemented in a setup consisting of discrete SiC MOSFET units. Thus, the power loss of the transistors with and without stray inductance can be compared. Similarly slower switching speeds are also implemented to fully emulate a 62-mm module. The power loss induced by the package can thus be evaluated.
  •  
33.
  • Sadik, Diane-Perle, 1988-, et al. (författare)
  • Comparison of thermal stress during short-circuit in different types of 1.2 kV SiC transistors based on experiments and simulations
  • 2016
  • Ingår i: Materials Science Forum. - : Trans Tech Publications Inc.. - 9783035710434 ; , s. 595-598
  • 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.
  •  
34.
  • Sadik, Diane-Perle, 1988-, et al. (författare)
  • Humidity Testing of SiC Power MOSFETs – An Update
  • 2017
  • 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.
  •  
35.
  • Sadik, Diane-Perle, et al. (författare)
  • Impact of blanking time on switching losses in a SiC MOSFET-based converter using capacitive snubbers
  • 2019
  • Ingår i: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe. - : Institute of Electrical and Electronics Engineers (IEEE). - 9789075815313
  • 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.
  •  
36.
  • Sadik, Diane-Perle, 1988-, et al. (författare)
  • Introduction of SiC MOSFETs in Converters based on Si IGBTs : A Reliability and Efficiency Analysis
  • 2017
  • 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
  • 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.
  •  
37.
  • Sadik, Diane-Perle, 1988-, et al. (författare)
  • Short-Circuit Protection Circuits for Silicon-Carbide Power Transistors
  • 2016
  • Ingår i: IEEE Transactions on Industrial Electronics. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0278-0046 .- 1557-9948. ; 63:4, s. 1995-2004
  • 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.
  •  
38.
  • Sharifabadi, K., et al. (författare)
  • Design, control and application of modular multilevel converters for HVDC transmission systems
  • 2016
  • Bok (övrigt vetenskapligt/konstnärligt)abstract
    • Design, Control and Application of Modular Multilevel Converters for HVDC Transmission Systems is a comprehensive guide to semiconductor technologies applicable for MMC design, component sizing control, modulation, and application of the MMC technology for HVDC transmission. Separated into three distinct parts, the first offers an overview of MMC technology, including information on converter component sizing, Control and Communication, Protection and Fault Management, and Generic Modelling and Simulation. The second covers the applications of MMC in offshore WPP, including planning, technical and economic requirements and optimization options, fault management, dynamic and transient stability. Finally, the third chapter explores the applications of MMC in HVDC transmission and Multi Terminal configurations, including Supergrids. Key features: Unique coverage of the offshore application and optimization of MMC-HVDC schemes for the export of offshore wind energy to the mainland. Comprehensive explanation of MMC application in HVDC and MTDC transmission technology. Detailed description of MMC components, control and modulation, different modeling approaches, converter dynamics under steady-state and fault contingencies including application and housing of MMC in HVDC schemes for onshore and offshore. Analysis of DC fault detection and protection technologies, system studies required for the integration of HVDC terminals to offshore wind power plants, and commissioning procedures for onshore and offshore HVDC terminals. A set of self-explanatory simulation models for HVDC test cases is available to download from the companion website. This book provides essential reading for graduate students and researchers, as well as field engineers and professionals who require an in-depth understanding of MMC technology.
  •  
39.
  • Tolstoy, Georg, et al. (författare)
  • Dual control used in series-loaded resonant converter with SiC devices
  • 2015
  • Ingår i: Power Electronics and ECCE Asia (ICPE-ECCE Asia), 2015 9th International Conference on. - : IEEE. ; , s. 495-501
  • Konferensbidrag (refereegranskat)abstract
    • 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.
  •  
40.
  • Tolstoy, Georg, et al. (författare)
  • Experimental evaluation of SiC BJTs and SiC MOSFETs in a series-loaded resonant converter
  • 2015
  • Ingår i: Power Electronics and Applications (EPE’15 ECCE-Europe), 2015 17th European Conference on. - : IEEE. ; , s. 1-9
  • Konferensbidrag (refereegranskat)abstract
    • 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.
  •  
41.
  • Toth-Pal, Zsolt, et al. (författare)
  • Thermal improvement of press-pack packages : Pressure dependent thermal contact resistance with a thin silver interlayer between molybdenum substrate and silicon carbide chip
  • 2017
  • Ingår i: 2017 IEEE International Workshop on Integrated Power Packaging, IWIPP 2017. - : IEEE. - 9781509042784
  • Konferensbidrag (refereegranskat)abstract
    • In typical press-pack, free-floating packages the thermal contact resistance between chip and substrate is a major limiting factor for the cooling ability of the power module. We report an introduction of a new, thin Silver interlayer between Molybdenum substrate and chip, and how it improves the thermal contact. The thermal contact resistances were measured with and without a Silver interlayer at different pressures. The surface roughness of the SiC chip and the Molybdenum substrate were characterized. The thermal contact resistances were measured at three different heating power levels. The results show a significant reduction of the thermal contact resistance with only a few micrometer Silver interlayer. The improved cooling effect of a Silver interlayer was also demonstrated with a fluid dynamics type of 3 D simulation comparing temperature distributions with and without a Silver interlayer. These results project a possible thermal improvement in press-pack packages.
  •  
42.
  • Velander, Erik, et al. (författare)
  • An IGBT Turn-ON Concept Offering Low Losses Under Motor Drive dv/dt Constraints Based on Diode Current Adaption
  • 2018
  • Ingår i: IEEE transactions on power electronics. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0885-8993 .- 1941-0107. ; 33:2, s. 1143-1153
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, a new low-loss turn-ON concept for the silicon insulated-gate bipolar transistor (Si-IGBT) in combination with silicon p-i-n diode is presented. The concept is tailored for two-level motor converters in the 100 kW to 1 MW range under the constraint that the output voltages slopes are limited in order to protect the motor windings. Moreover, analyses of the IGBT turn-ON and diode reverse recovery voltage slopes are presented concluding that the diode reverse recovery is the worst case. The concept includes a low-cost measurement of the free-wheeling diode current and temperature by the gate driver without necessity of acquiring this information from the converter control board. By using this concept, the output dv/dt at the diode turn-OFF can be kept approximately constant regardless of the commutated current and junction temperature. Hence, the switching losses could be decreased for the currents and temperatures where the voltage slopes are lower when using a conventional gate driver optimized for the worst case. Moreover, results are shown for one such power semiconductor, showing a total switching loss reduction of up to 28% in comparison with a gate driver without current and temperature measurement. Finally, this concept is particularly suitable for high power semiconductor modules in half-bridge configuration which are recently proposed by several suppliers.
  •  
43.
  • Velander, Erik, et al. (författare)
  • An Ultralow Loss Inductorless dv/dt Filter Concept for Medium-Power Voltage Source Motor Drive Converters With SiC Devices
  • 2018
  • Ingår i: IEEE transactions on power electronics. - : IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. - 0885-8993 .- 1941-0107. ; 33:7, s. 6072-6081
  • Tidskriftsartikel (refereegranskat)abstract
    • In this paper, a novel dv/dt filter is presented targeted for 100-kW to 1-MW voltage source converters using silicon carbide (SiC) power devices. This concept uses the stray inductance between the power device and the converter output as a filter component in combination with an additional small RC-link. Hence, a lossy, bulky, and costly filter inductor is avoided and the resulting output dv/dt is limited to 5-10 kV/mu s independent of the output current and switching speed of the SiC devices. As a consequence, loads with dv/dt constraints, e.g., motor drives can be fed from SiC devices enabling full utilization of their high switching speed. Moreover, a filter-model is proposed for the selection of filter component values for a certain dv/dt requirement. Finally, results are shown using a 300-A 1700-V SiC metal-oxide-semiconductor field-effect transistor (MOSFET). These results show that the converter output dv/dt can be limited to 7.5 kV/mu s even though values up to 47 kV/mu s weremeasured across the SiC MOSFET module. Hence, the total switching losses, including the filter losses, are verified to be three times lower compared to when the MOSFET dv/dt was slowed down by adjusting the gate driver.
  •  
44.
  • Velander, Erik, 1980- (författare)
  • On Gate Drivers for MOS-Controlled Power Devices and dv-dt Filters for Train Traction Converters
  • 2017
  • Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
    • In this thesis, low-loss gate-drive solutions and a proposed dv/dt-filter have been investigated with focus on train traction converters with dv/dt constraints.By using the silicon carbide (SiC) junction field-effect transistor (JFET), the switching losses can be significantly reduced compared to the commonly used insulated-gate bipolar transistor (IGBT), but complex gate-driver solutions are required for high utilization in terms of loss reduction.For the IGBT and the p-i-n diode, the dv/dt across the diode at the turn-ON process of the IGBT was found to be as highest with low phase current and low temperature while the losses are as highest at high phase currents and temperatures. Therefore, a proposal meeting this tradeoff has been addressed in this thesis tailored at minimal cost for the new half-bridge package resulting in a switching loss reduction of up to 30 %.For the SiC metal oxide semiconductor field effect transistor (MOSFET), an investigation has been performed in order to use the train operation point in order to minimize the switching losses given a certain dv/dt requirement. In addition, separate control of the di/dt and dv/dt were implemented. In total, a loss reduction of 20 % is achieved. In addition, phase short-circuit investigations have been performed using the SiC MOSFET with a gate-driver proposal meeting the application requirements. The results show that short circuits with fast current rise can be terminated.Finally, a new dv/dt filter which uses the stray inductance present in the inter-connections between the power devices and the convert output terminals as a filter component is proposed. By doing so, the SiC MOSFETs can be fully utilized with high dv/dt and low switching losses even though the converter output dv/dt levels are in the range of the levels for which an IGBT equipped converter exhibits with ultra-low additional filter losses. As a consequence, the switching frequency can be four times higher for the same switching losses.
  •  
45.
  •  
46.
  • Zhang, H., et al. (författare)
  • SISO Transfer Functions for Stability Analysis of Grid-Connected Voltage-Source Converters
  • 2019
  • Ingår i: IEEE transactions on industry applications. - : Institute of Electrical and Electronics Engineers Inc.. - 0093-9994 .- 1939-9367. ; 55:3, s. 2931-2941
  • Tidskriftsartikel (refereegranskat)abstract
    • Converter-grid interaction is of great interest in a weak-grid condition. This paper presents a single-input-single-output (SISO) open-loop transfer function for the stability analysis of grid-connected voltage-source converters. Differing from the conventional input impedance method and the eigenvalue analysis, an alternative multi-input-multi-output closed-loop system is developed in the paper and it eventually yields an SISO open-loop transfer function. This enables the application of a single Nyquist curve for analyzing the overall system stability. The model is validated against time-domain simulations as well as experimental results showing excellent accuracy for predicting the system stability.
  •  
47.
  • Zhang, Hongyang, et al. (författare)
  • SISO Transfer Functions for Stability Analysis of Grid-Connected Voltage-Source Converters
  • 2018
  • Ingår i: 2018 International Power Electronics Conference (IPEC-NIIGATA 2018 -ECCE ASIA). - : Institute of Electrical and Electronics Engineers (IEEE). - 9784886864055 ; , s. 3684-3691
  • Konferensbidrag (refereegranskat)abstract
    • Converter grid interaction is of great interest in a weak-grid condition. In this paper, an alternative multi-input multi-output closed-loop system is developed for the stability analysis of grid-connected voltage-source converters. In contrast to the conventional dq-impedance model and the eigenvalue analysis, this model eventually yields a single-input single-output transfer function. This enables to apply a single Nyquist curve for analyzing the overall system stability. The model is validated against time domain simulations and it shows excellent accuracy for predicting the system stability.
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