| 1. |
- Kersten, Anton, 1991, et al.
(författare)
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Review of Technical Design and Safety Requirements for Vehicle Chargers and Their Infrastructure According to National Swedish and Harmonized European Standards
- 2021
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 14:11
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Forskningsöversikt (refereegranskat)abstract
- Battery electric vehicles demand a wide variety of charging networks, such as charging stations and wallboxes, to be set up in the future. The high charging power (typically in the range of a couple of kW up to a couple of hundred kW) and the possibly long duration of the charging process (up to more than 24 h) put some special requirements on the electrical infrastructure of charging stations, sockets, and plugs. This paper gives an overview of the technical design requirements and considerations for vehicle charging stations, sockets, and plugs, including their infrastructure, according to the Swedish Standard 4364000, "Low-voltage electrical installations-Rules for design and erection of electrical installations", and the corresponding harmonized European standards. In detail, the four internationally categorized charging modes are explained and the preferable charging plugs, including their two-bus communication, according to European Directives are shown. The dimensioning of the supply lines and the proper selection of the overcurrent protection device, the insulation monitor, and the residual current device are described. Furthermore, a comprehensive overview of the required safety measures, such as the application of an isolation transformer or the implementation of an overvoltage protection mechanism, and the limits for conducted electromagnetic emissions, such as low-frequency harmonics or high-frequency (150 kHz to 108 MHz) emissions, are given.
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| 2. |
- Acquaviva, Alessandro, 1987, et al.
(författare)
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Analytical Conduction Loss Calculation of a MOSFET Three-Phase Inverter Accounting for the Reverse Conduction and the Blanking Time
- 2021
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Ingår i: IEEE Transactions on Industrial Electronics. - 0278-0046 .- 1557-9948. ; 68:8, s. 6682-6691
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Tidskriftsartikel (refereegranskat)abstract
- The reverse conduction capability of MOSFETs is beneficial for the efficiency of a three-phase inverter. In this paper analytical expressions in closed form are presented which allow to quickly evaluate the conduction losses, considering the effect of the reverse conduction and blanking time for both sinusoidal PWM operation with and without third harmonic injection. The losses of a three-phase SiC MOSFET inverter suitable for traction applications are estimated with the proposed method and show good agreement of about 98.5 % with measurements, performed with a calorimetric setup.
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| 3. |
- Buberger, Johannes, et al.
(författare)
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Charging Strategy for Battery Electric Vehicles with a Battery Modular Multilevel Management (BM3) Converter System using a PR controller
- 2021
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Ingår i: 2021 23rd European Conference on Power Electronics and Applications, EPE 2021 ECCE Europe.
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Konferensbidrag (refereegranskat)abstract
- Modular Multilevel Converters (MMC) with integrated battery packs have been proven to be a viable option for various electric power applications. In novel applications, fully charged battery packs are used to form flexible output voltage waveforms. Nonetheless, the charging of the batteries after the actual usage has previously not been described for MMC based inverters with integrated battery packs. This paper presents an approach of power grid compliant electric vehicle battery charging for Battery Modular Multilevel Management (BM3) converter systems with three-switch modules using a PR controller when directly connected to the AC grid. By using such a system, the conventional battery electric vehicle's on-board charger and any additional battery balancing circuitry become obsolete. It is demonstrated, that the analyzed approach is able to charge the battery modules with a current total harmonic distortion of less than 5% at any charging power level without the usage of a dedicated grid filter. Furthermore, the power factor angle can be freely adjusted.
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| 4. |
- Estaller, Julian, et al.
(författare)
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Battery Impedance Modeling and Comprehensive Comparisons of State-Of-The-Art Cylindrical 18650 Battery Cells considering Cells' Price, Impedance, Specific Energy and C-Rate
- 2021
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Ingår i: 21st IEEE International Conference on Environment and Electrical Engineering and 2021 5th IEEE Industrial and Commercial Power System Europe, EEEIC / I and CPS Europe 2021 - Proceedings.
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Konferensbidrag (refereegranskat)abstract
- Within different areas of research and development of battery cells and systems, it is necessary to include electrical models of battery cells in simulations to reflect batteries' behavior. Linear or nonlinear electrical equivalent circuit models are commonly used for this purpose, such as the Warburg impedance and the three RC-pair model. In this paper, various protected and unprotected commercially available cylindrical (18650), state-of-the-art lithium-ion battery cells are considered. Their impedance parameters, according to the aforementioned models, are estimated using electrochemical impedance spectroscopies. Furthermore, the selected battery cells are comprehensively compared in terms of their price, impedance, specific energy and C-rate. Therefore, this paper provides a brief but comprehensive battery parameter library, which should assist battery system designers or power electronic engineers to conduct battery simulations and, thus, to properly choose battery cells with respect to application specific requirements.
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| 5. |
- Högerl, Tobias, et al.
(författare)
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Battery Emulation for Battery Modular Multilevel Management (BM3) Converters and Reconfigurable Batteries with Series, Parallel and Bypass Function
- 2021
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Ingår i: 21st IEEE International Conference on Environment and Electrical Engineering and 2021 5th IEEE Industrial and Commercial Power System Europe, EEEIC / I and CPS Europe 2021 - Proceedings. ; , s. 1227-1234
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Konferensbidrag (refereegranskat)abstract
- This paper deals with the emulation of lithium-ion battery cells/modules for the development and testing of battery modular multilevel management converters and any kind of reconfigurable battery systems with series, parallel and bypass function. The developed emulator is based on a buck converter type with an isolated input voltage supply. A circuit board with the form factor of two cylindrical 18650 battery cells was developed, which can function as a replacement of a real battery cell/module for a laboratory setup. In addition to the implemented safety mechanisms, such as over-current, over-voltage and short-circuit protection, a simplified electrical equivalent circuit model is implemented on the integrated micro controller. Thereby, the dynamic electrical behavior of any battery cell can be emulated with low deviations from its real battery behavior.
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| 6. |
- Kersten, Anton, 1991, et al.
(författare)
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Hybrid Output Voltage Modulation (PWM-FSHE) for a Modular Battery System Based on a Cascaded H-Bridge Inverter for Electric Vehicles Reducing Drivetrain Losses and Current Ripple
- 2021
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 14:5
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Tidskriftsartikel (refereegranskat)abstract
- This paper shows a preliminary study about the output voltage modulation of a modular battery system based on a seven-level cascaded H-bridge inverter used for vehicle propulsion. Two generally known modulation techniques, pulse width modulation (PWM) and fundamental selective harmonic elimination (FSHE), are extensively compared for such an innovative modular battery system inverter considering EVs' broad torque-speed range. The inverter and the battery losses, as well as the inverter-induced current THD, are modeled and quantified using simulations. At low speeds, if the modulation index M is below 0.3, FSHE induces a high current THD (>>5%) and, thus, cannot be used. At medium speeds, FSHE reduces the drivetrain losses (including the battery losses), while operating at higher speeds, it even reduces the current THD. Thus, an individual boundary between multilevel PWM and FSHE can be determined using weightings for efficiency and current quality. Based on this, a simple hybrid modulation technique is suggested for modular battery system inverters, improving the simulated drive cycle efficiency by a maximum of 0.29% to 0.42% for a modeled small passenger vehicle. Furthermore, FSHE's high speed dominance is demonstrated using a simple experimental setup with an inductive load.
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| 7. |
- Kersten, Anton, 1991, et al.
(författare)
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Measuring and Separating Conducted Three-Wire Emissions from a Fault-Tolerant, NPC Propulsion Inverter with a Split-Battery Using Hardware Separators Based on HF Transformers
- 2021
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Ingår i: IEEE Transactions on Power Electronics. - 0885-8993 .- 1941-0107. ; 36:1, s. 378-390
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Tidskriftsartikel (refereegranskat)abstract
- Conducted emissions on the traction battery's power cables in EVs must be limited to avoid unwanted electromagnetic interference (EMI). When designing an EMI filter, it is advantageous to have information of the common mode (CM) and differential mode (DM) noise levels. This article deals with the measurement and separation of the dc side's three-wire DM/CM noise of a fault-tolerant three-level neutral-point-clamped (NPC) inverter with a split-battery system. Two hardware separators, based on small-circuit highfrequency transformers, were developed to identify the dc side's CM, line-DM, and phase-DM noise levels. Their characterized CM and DM rejection ratios for the frequency range from 150 kHz to 110 MHz are at least -33 and -21 dB, respectively. The separated noise of the NPC inverter was measured, using an inductive load, when operating the inverter with three-level and two-level modulation, resembling normal operation and a possible operation under fault, respectively. A simple three-wire CM model of the used testbed and the DM power module oscillation were derived to validate the separated noise's resonance peaks/valleys. It has been seen that the CM noise is dominant, especially below 10 MHz, except for the power module oscillations. Furthermore, when using the two-level modulation, in the case of a clamping diode fault, the noise levels are increased by about 3 dB.
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| 8. |
- Kersten, Anton, 1991
(författare)
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Modular Battery Systems for Electric Vehicles based on Multilevel Inverter Topologies - Opportunities and Challenges
- 2021
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Modular battery systems based on multilevel inverter (MLI) topologies can possibly overcome some shortcomings of two-level inverters when used for vehicle propulsion. The results presented in this thesis aim to point out the advantages and disadvantages, as well as the technical challenges, of modular vehicle battery systems based on MLIs in comparison to a conventional, two-level IGBT inverter drivetrain. The considered key aspects for this comparative investigation are the drive cycle efficiency, the inverter cost, the fault tolerance capability of the drivetrain and the conducted electromagnetic emissions. Extensive experiments have been performed to support the results and conclusions. In this work, it is shown that the simulated drive cycle efficiency of different low-voltage-MOSFET-based, cascaded seven-level inverter types is improved in comparison to a similarly rated, two-level IGBT inverter drivetrain. For example, the simulated WLTP drive cycle efficiency of a cascaded double-H-bridge (CDHB) inverter drivetrain in comparison to a two-level IGBT inverter, when used in a small passenger car, is increased from 94.24% to 95.04%, considering the inverter and the ohmic battery losses. In contrast, the obtained efficiency of a similar rated seven-level cascaded H-bridge (CHB) drivetrain is almost equal to that of the two-level inverter drivetrain, but with the help of a hybrid modulation technique, utilizing fundamental selective harmonic elimination at lower speeds, it could be improved to 94.85%. In addition, the CDHB and CHB inverters’ cost, in comparison to the two-level inverter, is reduced from 342€ to 202€ and 121€, respectively. Furthermore, based on a simple three-level inverter with a dual battery pack, it is shown that MLIs inherently allow for a fault tolerant operation. It is explained how the drivetrain of a neutral point clamped (NPC) inverter can be operated under a fault condition, so that the vehicle can drive with a limited maximum power to the next service station, referred to as limp home mode. Especially, the detection and localization of open circuit faults has been investigated and verified through simulations and experiments. Moreover, it is explained how to measure the conducted emissions of an NPC inverter with a dual battery pack according to the governing standard, CISPR 25, because the additional neutral point connection forms a peculiar three-wire DC source. To separate the measured noise spectra into CM, line-DM and phase-DMquantities, two hardware separators based on HF transformers are developed and utilized. It is shown that the CM noise is dominant. Furthermore, the CM noise is reduced by 3dB to 6dB when operating the inverter with three-level instead of two-level modulation.
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| 9. |
- Lohse, Benjamin, et al.
(författare)
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The Modular Multilevel Magnetic Stimulator: Energy-Efficiency, Pre-Charging and Overlap Protection
- 2021
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Ingår i: IECON 2021 - 47TH ANNUAL CONFERENCE OF THE IEEE INDUSTRIAL ELECTRONICS SOCIETY. - 1553-572X. - 9781665435543
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Konferensbidrag (refereegranskat)abstract
- The technology of transcranial magnetic stimulation (TMS) enables to break new ground in medical research. It is suitable for different diagnostics, as well as therapeutic purposes, such as the treatment of depression or epilepsy, which are not fully explored yet. TMS devices that are currently available on the market offer a limited possibility for a targeted stimulation, due to their predefined voltage pulse shape. This paper presents a novel TMS device based on a multilevel inverter technology. Utilizing several cascaded sub-modules (built as H-bridges), arbitrary output waveforms can be discretely generated. At first, a theoretical part discusses how the energy efficiency of such a device can be increased by applying suitable control strategies and how it is possible to charge multiple sub-modules with only one auxiliary power supply. In addition, it is shown how to determine the required capacitance rating of a sub-module. Next, in the practical part, a designed prototype is presented and its current and voltage capabilities are verified, conducting 2.3 kA (peak-to-peak). In addition, the influence of different dead-times on the output voltage waveform is investigated. It is shown that the precise adjustment of the dead-time is crucial to ensure the proper switching of the required current without damaging the hardware.
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| 10. |
- Mashayekh, Ali, et al.
(författare)
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Proactive SoC Balancing Strategy for Battery Modular Multilevel Management (BM3) Converter Systems and Reconfigurable Batteries
- 2021
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Ingår i: 2021 23rd European Conference on Power Electronics and Applications, EPE 2021 ECCE Europe.
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Konferensbidrag (refereegranskat)abstract
- The battery modular multilevel management converter topology and different types of reconfigurable battery topologies have been proven to be a viable option for various electric power applications. This paper presents a unique SoC balancing approach for the integrated battery strands/packs of BM3 converter systems or reconfigurable batteries. The suggested approach alternately utilizes different redundant switching state combinations to balance and to keep the battery strands' SoCs balanced. Furthermore, the suggested algorithm attempts to utilize all converter modules, because the parallel connection of adjacent modules reduces the phase-strand's battery impedance. Furthermore, the presented approach tries to reduce the number of switching events when changing the switching state combination. Thereby, the ohmic battery losses and switching losses are kept as low as possible. Since no power is dissipated in designated bleeder resistors and no designated active balancing circuitry is required, the suggested approach can be categorized as a proactive balancing approach. Simulations are used to verify the algorithm's validity.
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| 11. |
- Neukirchinger, Fabian, et al.
(författare)
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Where Transcranial Magnetic Stimulation is headed to: The modular extended magnetic stimulator
- 2021
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Ingår i: 21st IEEE International Conference on Environment and Electrical Engineering and 2021 5th IEEE Industrial and Commercial Power System Europe, EEEIC / I and CPS Europe 2021 - Proceedings.
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Konferensbidrag (refereegranskat)abstract
- Transcranial magnetic stimulation (TMS) already suffered, even though first presented in 1985, a technical stagnation. Even though applications of stimulation patterns were optimized for treatment and research objectives, the technical buildup of transcranial magnetic stimulators only advances in terms of a reduced energy consumption, but never concerning the aspect of adjustable pulse shapes. This paper reviews prior technical advances of magnetic stimulators and their medical applications. Moreover, a novel multilevel stimulator is presented and it is analyzed how it could finally overcome the restriction of predefined pulse shapes. Finally,it is discussed how freely selectable pulse shapes might fundamentally change the way TMS is applied.
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| 12. |
- Schwitzgebel, Florian, et al.
(författare)
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Design and testing of a novel transcranial magnetic stimulator with adjustable pulse dynamics and high current capability (>2 ka) based on a modular cascaded h-bridge inverter topology
- 2021
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Ingår i: PCIM Europe Conference Proceedings. - 2191-3358. ; 2021-May, s. 206-213
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Konferensbidrag (refereegranskat)abstract
- Transcranial magnetic stimulation (TMS) is an important technology in neurological diagnostics and therapy. The limited output voltage shape of modern TM stimulators constrains the research about the targeted stimulation of individual brain parts. This paper introduces a novel TM stimulator based on a cascaded H-bridge inverter topology. Using a large number of sub-modules (e.g., ten), a nearly arbitrary output voltage waveform can be generated. Within the frame of this paper, the design and testing of an individual H-bridge module, using low-voltage MOSFETs, is explained in detail. To achieve a high current capability, the switching waveforms of the paralleled MOSFETs are synchronized by individual time delays introduced by an integrated CPLD. The H-bridge module is used for different experimental pulse tests. Using a DC link voltage of 180 V a maximum current peak of about 2.1 kA is achieved.
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| 13. |
- Sorokina, Nina, et al.
(författare)
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Inverter and Battery Drive Cycle Efficiency Comparisons of Multilevel and Two-Level Traction Inverters for Battery Electric Vehicles
- 2021
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Ingår i: 21st IEEE International Conference on Environment and Electrical Engineering and 2021 5th IEEE Industrial and Commercial Power System Europe, EEEIC / I and CPS Europe 2021 - Proceedings.
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Konferensbidrag (refereegranskat)abstract
- This paper investigates the drive cycle performance of different multilevel and two-level inverters. For the multilevel inverters, a cascaded H-bridge (CHB), a modular multilevel series parallel (MMSP) and a battery modular multilevel management (BM3) inverter are considered. The inverter and battery efficiency during the WLTP-driving cycle are estimated based on loss models. The battery loss model is derived from an electrochemical impedance spectroscopy of a cylindrical 18650 Li-ion battery cell. The inverter losses are modeled using the semiconductors' data sheets and a thermal equivalent circuit. In comparison to the two-level inverter system, the CHB and the MMSP inverter drivetrains show an increased inverter efficiency, despite increased battery losses. In contrast to the CHB and the BM3 topologies, the MMSP inverter shows less battery losses. The BM3 inverter shows acceptable drive cycle efficiency while having the lowest inverter costs.
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