| 1. |
- 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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| 2. |
- Buberger, Johannes, et al.
(författare)
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Total CO 2 -equivalent life-cycle emissions from commercially available passenger cars
- 2022
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Ingår i: Renewable and Sustainable Energy Reviews. - : Elsevier BV. - 1879-0690 .- 1364-0321. ; 159
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Tidskriftsartikel (refereegranskat)abstract
- The international passenger car market is undergoing a transition from vehicles with internal combustion engines to hybrid and fully electrified vehicles to reduce the climate impact of the transportation sector. To emphasize the importance of this needed change, this paper provides holistic comparisons of the total life-cycle greenhouse gas (GHG) emissions produced by a wide selection of commercially available passenger cars with different powertrains and energy sources. Simple analytical models are used to quantify the total life-cycle GHG emissions in terms of CO2-equivalent values relative to the vehicle curb weight and the peak motor power. The production, utilization and recycling emissions are separately quantified based on the latest reviewed emission coefficient values. In total 790 different vehicle variants are considered. The results show that Battery Electric Vehicles have the highest production emissions. For example, the additional production emissions of a Tesla Model 3 Standard Plus approximately correspond to the driving emissions of a Volkwagen Passat 2.0 TSI after 18 000km. Nonetheless, it is shown that conventional gasoline and diesel vehicles emit the highest amount of total life-cycle GHGs in comparison to vehicles powered by other available energy resources. When using green electricity, plug-in hybrid electric and fully electric vehicles can reduce the total life-cycle emission in comparison to combustion engine vehicles by 73% and 89%, respectively. A similar emission reduction is achieved by biogas powered vehicles (81%). Fuel cell vehicles approximately reduce the GHG emission to a similar extent as electric vehicles (charged with conventional electricity) when using commercially available gray hydrogen (60%).
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| 3. |
- 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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| 4. |
- 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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| 5. |
- Kuder, Manuel, et al.
(författare)
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Capacitor Voltage Balancing of a Grid-Tied, Cascaded Multilevel Converter with Binary Asymmetric Voltage Levels Using an Optimal One-Step-Ahead Switching-State Combination Approach †
- 2022
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Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 15:2
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Tidskriftsartikel (refereegranskat)abstract
- This paper presents a novel capacitor voltage balancing control approach for cascaded multilevel inverters with an arbitrary number of series-connected H-Bridge modules (floating capacitor modules) with asymmetric voltages, tiered by a factor of two (binary asymmetric). Using a nearest-level reference waveform, the balancing approach uses a one-step-ahead approach to find the optimal switching-state combination among all redundant switching-state combinations to balance the capacitor voltages as quickly as possible. Moreover, using a Lyapunov function candidate and considering LaSalle's invariance principle, it is shown that an offline calculated trajectory of optimal switching-state combinations for each discrete output voltage level can be used to operate (asymptotically stable) the inverter without measuring any of the capacitor voltages, achieving a novel sensorless control as well. To verify the stability of the one-step-ahead balancing approach and its sensorless variant, a demonstrator inverter with 33 levels is operated in grid-tied mode. For the chosen 33-level converter, the NPC main-stage and the individual H-bridge modules are operated with an individual switching frequency of about 1 kHz and 2 kHz, respectively. The sensorless approach slightly reduced the dynamic system response and, furthermore, the current THD for the chosen operating point was increased from 3.28% to 4.58% in comparison with that of using the capacitor voltage feedback.
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| 6. |
- 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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| 7. |
- 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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