| 1. |
- Kersten, Anton, 1991, et al.
(författare)
-
Online and On-Board Battery Impedance Estimation of Battery Cells, Modules or Packs in a Reconfigurable Battery System or Multilevel Inverter
- 2020
-
Ingår i: IECON Proceedings (Industrial Electronics Conference). - 2162-4704 .- 2577-1647. ; , s. 1884-1891
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Konferensbidrag (refereegranskat)abstract
- This paper shows two approaches to determine the battery impedance of battery cells or battery modules when used in a reconfigurable battery system (RBS) or in any type of modular multilevel converter (MMC) for electric drive applications. A generic battery model is used and the concepts of the recursive time and frequency-domain parameter extraction, using a current step and an electrochemical impedance spectroscopy, are explained. Thus, it is shown and demonstrated that the balancing current of neighboring cells/modules ,when in parallel operation, can be used, similar to the time-domain parameter extraction utilizing a current step, to determine the battery parameters. Furthermore, it is shown and demonstrated that a part of the inverter can be used as variable AC voltage source to control a sinusoidal current through the motor inductances of the drive train, which can be injected to the inserted battery cells/modules of an adjacent phase to perform an on-board impedance spectroscopy. Using either of the two presented approaches, the individual battery impedances can be easily determined, yielding the state of health (SOH) and the power capability of individual battery cells/modules. Nonetheless, the analyzed approaches were just considered to be applied at machine standstill, which is not suitable for grid-tied applications.
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| 2. |
- Kersten, Anton, 1991, et al.
(författare)
-
Review of Technical Design and Safety Requirements for Vehicle Chargers and Their Infrastructure According to National Swedish and Harmonized European Standards
- 2021
-
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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| 3. |
- Kuder, Manuel, et al.
(författare)
-
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
-
Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 15:2
-
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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| 4. |
- Abdul-Jabbar, Thealfaqar A., et al.
(författare)
-
Efficient Battery Cell Balancing Methods for Low-Voltage Applications: A Review
- 2022
-
Ingår i: 2022 IEEE International Conference in Power Engineering Application, ICPEA 2022 - Proceedings.
-
Konferensbidrag (refereegranskat)abstract
- Battery balancing technologies are a crucial mech anism for the safe operation of electrochemical energy storage systems, such as lithium-ion batteries. Moreover, balancing be tween battery cells is essential for battery systems' life. Without any balancing circuitry, individual cell voltages can reach their maximum/minimum battery voltage limit faster than others, posing safety hazards. Furthermore, battery capacity reduction can occur when overcharging/over-discharging individual cells. So far, many balancing methodologies have been proposed and discussed in available literature. This paper presents a review of different state-of-The-Art cell balancing methods suitable for low voltage applications. The required control complexity, switch stress, balancing speed, cost and circuit size are considered as key aspects. Typically, cell bypass techniques, such as passive balancing, have the lowest cost and require no complex control strategies. In contrast, cell-To-cell balancing techniques can significantly increase the energy efficiency compared to cell bypass balancers, but these come with higher system costs and control complexity.
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| 5. |
- Acquaviva, Alessandro, 1987, et al.
(författare)
-
Analytical Conduction Loss Calculation of a MOSFET Three-Phase Inverter Accounting for the Reverse Conduction and the Blanking Time
- 2021
-
Ingår i: IEEE Transactions on Industrial Electronics. - 0278-0046 .- 1557-9948. ; 68:8, s. 6682-6691
-
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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| 6. |
- Ban, Branko, et al.
(författare)
-
Torque Ripple Reduction Utilizing Pole-Shoe Extensions for a Traction Wound Field Synchronous Machine
- 2023
-
Ingår i: <em>2023 International Conference on Electrical Drives and Power Electronics, EDPE 2023 - Proceedings</em>. - : Institute of Electrical and Electronics Engineers Inc..
-
Konferensbidrag (refereegranskat)abstract
- This paper presents a comprehensive study on optimizing a water-cooled automotive traction Wound Field Synchronous Machine using an inverse-cosine pole-shaping variant with pole-shoe extensions. The objective was to maximize torque and minimize total loss at base speed, considering constraints like torque ripple, thermal loading, and mechanical stress yield factor. The optimization of the baseline design was conducted via a differential evolution algorithm. The design effectively fulfills all design requirements, maintaining the active volume constraints. Through iterative post-optimization adjustments of the pole shape, the effects on machine performance were analyzed. The inverse-cosine pole-shaping with novel pole-shoe extensions proves to be a superior approach. Compared to a design without pole-shoe extensions (6.49% torque ripple), the baseline design enables a ripple reduction of 2.45 %. The conclusion is that the pole-shoe extensions have considerable influence on torque-ripple.
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| 7. |
- Buberger, Johannes, et al.
(författare)
-
Charging Strategy for Battery Electric Vehicles with a Battery Modular Multilevel Management (BM3) Converter System using a PR controller
- 2021
-
Ingår i: 2021 23rd European Conference on Power Electronics and Applications, EPE 2021 ECCE Europe.
-
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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| 8. |
- Buberger, Johannes, et al.
(författare)
-
Total CO 2 -equivalent life-cycle emissions from commercially available passenger cars
- 2022
-
Ingår i: Renewable and Sustainable Energy Reviews. - : Elsevier BV. - 1879-0690 .- 1364-0321. ; 159
-
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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| 9. |
- Estaller, Julian, et al.
(författare)
-
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
-
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.
-
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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| 10. |
- Estaller, Julian, et al.
(författare)
-
Overview of Battery Impedance Modeling Including Detailed State-of-the-Art Cylindrical 18650 Lithium-Ion Battery Cell Comparisons
- 2022
-
Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 15:10
-
Tidskriftsartikel (refereegranskat)abstract
- Electrical models of battery cells are used in simulations to represent batteries' behavior in various fields of research and development involving battery cells and systems. Electrical equivalent circuit models, either linear or nonlinear, are commonly used for this purpose and are presented in this article. Various commercially available cylindrical, state-of-the-art lithium-ion battery cells, both protected and unprotected, are considered. Their impedance properties, according to four different equivalent circuit models, are measured using electrochemical impedance spectroscopies. Furthermore, the pricing, impedance, specific energy, and C-rate of the chosen battery cells are compared. For example, it is shown that the energy density of modern 18650 cells can vary from a typical value of 200 to about 260 Wh kg(-1), whereas the cell price can deviate by a factor of about 3 to 5. Therefore, as a result, this study presents a concise but comprehensive battery parameter library that should aid battery system designers or power electronic engineers in conducting battery simulations and in selecting appropriate battery cells based on application-specific requirements. In addition, the accuracies and computational efforts of the four equivalent circuit models are compared.
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| 11. |
- Han, Weiji, 1987, et al.
(författare)
-
Analysis and estimation of the maximum circulating current during the parallel operation of reconfigurable battery systems
- 2020
-
Ingår i: 2020 IEEE Transportation Electrification Conference and Expo, ITEC 2020. ; , s. 229-234
-
Konferensbidrag (refereegranskat)abstract
- Reconfigurable battery systems (RBSs) are emerging as a promising solution to safe, efficient, and robust energy storage and delivery through dynamically adjusting the battery connection topology. When the system connection is switched from series to parallel, circulating currents between parallel battery cells/modules can be triggered due to their voltage imbalance. During the hardware design of an RBS, the current rating of associated components, such as batteries, switches, and wires, depends on the maximum circulating currents. Moreover, given a developed RBS, the maximum circulating current also determines whether it is feasible to perform the relevant system reconfiguration. Thus, this paper is focused on modeling and analyzing the current distribution during the series-to-parallel battery reconfiguration and estimating the maximum circulating currents as well as their upper bound under various system states and operating scenarios. A prototype is set up to experimentally verify the effectiveness of the proposed method for estimating the maximum circulating currents.
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| 12. |
- Han, Weiji, 1987, et al.
(författare)
-
Analysis and Estimation of the Maximum Switch Current during Battery System Reconfiguration
- 2022
-
Ingår i: IEEE Transactions on Industrial Electronics. - 0278-0046 .- 1557-9948. ; 69:6, s. 5931-5941
-
Tidskriftsartikel (refereegranskat)abstract
- Batteries are interconnected in series and/or parallel to meet wide-range power or energy demands in various industrial applications. To pursue the benefits of multiple connection structures in one system, reconfigurable battery systems (RBSs) have recently emerged for safe and efficient operation, extended energy storage and delivery, etc. Switches are the essential elements to enable the battery system reconfiguration, but selecting appropriate switches for RBS designs has not been systematically investigated. To bridge this gap, analytical expressions are derived in this paper to estimate the maximum switch current and its upper limit to facilitate the selection of RBS switches. An RBS prototype based on H-bridges is set up and experimental results verify the effectiveness and advantage of the proposed estimation method. These analytical expressions, relying only on resistances of batteries and switches, are readily applicable to practical RBS design and much more efficient than conducting numerous circuit experiments, simulation tests, or circuit analyses, especially for large-scale systems. Moreover, the analysis framework and estimation method proposed for series-parallel mutual conversion can be adaptively extended to other complex system reconfigurations to facilitate various RBS designs.
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| 13. |
- Han, Weiji, 1987, et al.
(författare)
-
Next-Generation Battery Management Systems: Dynamic Reconfiguration
- 2020
-
Ingår i: IEEE Industrial Electronics Magazine. - 1941-0115 .- 1932-4529. ; 14:4, s. 20-31
-
Tidskriftsartikel (refereegranskat)abstract
- Batteries are widely applied to the energy storage and power supply in portable electronics, transportation, power systems, communication networks, etc. They are particularly demanded in the emerging technologies of vehicle electrification and renewable energy integration for a green and sustainable society. To meet various voltage, power, and energy requirements in large-scale applications, multiple battery cells have to be connected in series and/or parallel. While battery technology has advanced significantly in the past decade, existing battery management systems (BMSs) mainly focus on state monitoring and control of battery systems packed in fixed configurations. In fixed configurations, though, the battery system performance is in principle limited by the weakest cells, which can leave large parts severely underutilized. Allowing dynamic reconfiguration of battery cells, on the other hand, allows individual and flexible manipulation of the battery system at cell, module, and pack levels, which may open up a new paradigm for battery management. Following this trend, this paper provides an overview of next-generation BMSs featuring dynamic reconfiguration. Motivated by numerous potential benefits of reconfigurable battery systems (RBSs), the hardware designs, management principles, and optimization algorithms for RBSs are sequentially and systematically discussed. Theoretical and practical challenges during the design and implementation of RBSs are highlighted in the end to stimulate future research and development.
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| 14. |
- Högerl, Tobias, et al.
(författare)
-
Battery Emulation for Battery Modular Multilevel Management (BM3) Converters and Reconfigurable Batteries with Series, Parallel and Bypass Function
- 2021
-
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
-
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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| 15. |
- Kersten, Anton, 1991, et al.
(författare)
-
Battery Loss and Stress Mitigation in a Cascaded H-Bridge Multilevel Inverter for Vehicle Traction Applications by Filter Capacitors
- 2019
-
Ingår i: IEEE Transactions on Transportation Electrification. - 2332-7782. ; 5:3, s. 659-671
-
Tidskriftsartikel (refereegranskat)abstract
- In this paper, two types of filter capacitors of varying capacity, were connected to the battery packs of a cascaded H-Bridge single-star multilevel vehicle traction inverter, and their influence on the battery losses has been analyzed. The battery and capacitor simulation models used are experimentally verified in a down-scaled system. Different capacitor configurations were simulated for four drive cycle scenarios to determine the potentials for the mitigation of current pulse stresses and battery loss reduction with respect to the added weight. By adding capacitors corresponding to a weight of 4% of the initial battery storage, the peak current is reduced by 5%-20%, depending on the operating point from DC to a few kHz, and the battery losses are reduced by 10%. In comparison, it is demonstrated that adding supercapacitors is more beneficial for lower output frequencies, while adding electrolytic capacitors is better for higher output frequencies. Furthermore, the low-order voltage harmonics of the DC-rails between the converter and battery were reduced by 10%-30% for frequencies above 9 kHz, which decreases the potential of electromagnetic disturbances. In addition, during cold battery temperatures, when it is very important to avoid heavy cyclings, the loss reduction using the capacitors was 2.5 times larger than for nominal temperature.
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| 16. |
- Kersten, Anton, 1991, et al.
(författare)
-
CM & Line-Dm Noise Separation for Three-Level NPC Inverter with Connected Neutral Point for Vehicle Traction Applications
- 2019
-
Ingår i: ITEC 2019 - 2019 IEEE Transportation Electrification Conference and Expo. ; June 2019, s. 1-6
-
Konferensbidrag (refereegranskat)abstract
- EMI standards limit the noise level for conducted disturbances on DC power cables of electric vehicles. However, designing the EMI filter requires the information about the CM and DM noise levels. Therefore, a separation of the noise is needed. This paper deals with the separation and quantification of the three-phase DM and CM noise for a three-level NPC inverter with a connected neutral point. A hardware separator, based on HF transformers was developed to separate the noise into CM and line-DM noise. The CM and line-DM noise of the NPC inverter was measured, when operating the inverter with a two-level and a three-level modulation. As expected, the CM noise is dominating, and it is shown that the three-level operation reduces the noise compared to the two-level operation by about 3 to 6 dB.
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| 17. |
- Kersten, Anton, 1991, et al.
(författare)
-
Efficiency of Active Three-Level and Five-Level NPC Inverters Compared to a Two-Level Inverter in a Vehicle
- 2018
-
Ingår i: 2018 20th European Conference on Power Electronics and Applications, EPE 2018 ECCE Europe. - 9789075815283 ; , s. 1-9
-
Konferensbidrag (refereegranskat)abstract
- This paper deals with a comparison of a standard two-level inverter, with a three-level and a five-level active neutral point clamped (ANPC) inverter for vehicle traction applications. The inverter efficiencies during different drive cycles are assessed and an efficiency enhancement of the multilevel inverters for partial loading and different drive cycle scenarios is found.
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| 18. |
- Kersten, Anton, et al.
(författare)
-
Electric Vehicle Heating Management Techniques utilizing Drivetrain-Loss-Heating of Refrigerant
- 2022
-
Ingår i: IECON Proceedings (Industrial Electronics Conference). - 2577-1647 .- 2162-4704. ; 2022-October
-
Konferensbidrag (refereegranskat)abstract
- Resistive cabin heaters can significantly reduce the driving range of battery electric vehicles in cold climate conditions. Heat pump solutions can mitigate this drawback, but these are also complemented with resistive heaters which are often unnecessary in warmer climates. This paper investigates different drivetrain-loss-heating techniques, which can be used as redundancy or as a replacement for the resistive heater. With the help of different software tools, the achievable electric drive unit (EDU) losses, considering the motor and inverter losses, of a Volkswagen ID.3 are simulated. When driving at lower speeds or standstill, the EDU losses can be regulated via the stator current magnitude. As demonstrated, this method increases the torque ripple, but the generated heat losses, varying from 5.8 kW to 7.9 kW, are sufficient to fulfill the cold climate heating requirements. When operated at standstill, a declutched motor can achieve comparable heat losses, but disconnectors are seldomly used in battery electric vehicles. When using balanced three-phase DC currents at standstill, the heat losses vary from 4.6 kW to 5.4 kW depending on the rotor position, which might not be sufficient to fulfill the required heating capacity at cold climates.
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| 19. |
- Kersten, Anton, 1991, et al.
(författare)
-
Elimination/Mitigation of Output Voltage Harmonics for Multilevel Converters Operated at Fundamental Switching Frequency using Matlab's Genetic Algorithm Optimization
- 2020
-
Ingår i: 2020 22nd European Conference on Power Electronics and Applications, EPE 2020 ECCE Europe. ; , s. 1-12
-
Konferensbidrag (refereegranskat)abstract
- This paper deals with the optimization of the output voltage waveform of a multilevel converter operated with fundamental frequency switching. For a high number of output voltage levels, nearest-level control is typically used, whereas an optimized waveform can be presumably used to eliminate a selection of low order harmonics. A nonlinear optimization problem for any kind of multilevel inverter, operating in a single or three-phase arrangement, is formulated. It is shown that the set of nonlinear equations, defining this optimization problem, cannot be numerically solved, if the number of output voltage levels is higher than nine. Thus, an optimization algorithm, e.g., Matlab's genetic algorithm, should be used instead. Based on the concept of the weighted THD, it is shown that an optimized waveform has no effect on the output current's quality of a single phase multilevel converter. However, considering an ungrounded three-phase system, the content of the to be eliminated harmonic components is shifted towards the triplen harmonics and, consequently, the expected current quality, based on the WTHD, can be significantly improved.
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| 20. |
- Kersten, Anton, 1991, et al.
(författare)
-
Fault Detection and Localization for Limp Home Functionality of Three-Level NPC Inverters with Connected Neutral Point for Electric Vehicles
- 2019
-
Ingår i: IEEE Transactions on Transportation Electrification. - 2332-7782. ; 5:2, s. 416-432
-
Tidskriftsartikel (refereegranskat)abstract
- This paper deals with the detection of single battery or inverter switch faults during operation of a common and an active three-level neutral-point-clamped (NPC) inverter with a connected neutral point. Here, the main focus lies on the detection and localization of open-circuit faults of the inverter's switches. Therefore, a fault detection algorithm, using a current estimator, and two fault localization algorithms, a pulse pattern injection principle and an online adaption of the space vector modulation (SVM), are investigated and verified through simulations and experiments. Also, investigated is how the powertrain can be operated under a fault condition, so that the vehicle can drive with a limited maximum power using an adapted SVM, referred to as "limp home" mode, to the next service station. It is shown, that an active NPC inverter can cope with any single short or open-circuit fault of the inverter's switches without bringing the vehicle to standstill, whereas a generic NPC inverter loses controllability if an open-circuit fault at an inner switch occurs. Furthermore, both inverter types are able to be operated just with half of the dc-link voltage in case of a failure in one part of the battery.
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| 21. |
- Kersten, Anton, 1991, et al.
(författare)
-
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
-
Ingår i: Energies. - : MDPI AG. - 1996-1073 .- 1996-1073. ; 14:5
-
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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| 22. |
- Kersten, Anton, 1991, et al.
(författare)
-
Inverter and Battery Drive Cycle Efficiency Comparisons of CHB and MMSP Traction Inverters for Electric Vehicles
- 2019
-
Ingår i: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe. ; , s. 1-12
-
Konferensbidrag (refereegranskat)abstract
- This paper investigates the performance of several inverter types for electric vehicles. A standard two-level and two seven-level multilevel inverters, a cascaded H-bridge (CHB) and a modular multilevel series parallel (MMSP) inverter, are considered. Based on the AC impedance spectra measured on a single battery cell, the battery pack impedances of the multilevel and two-level inverter systems are modeled. The inverter losses are modeled using the semiconductors’ datasheets. Based on the loss models, the inverter and battery efficiency during different driving cycles are assessed. In comparison to the two-level inverter system, the multilevel inverter drivetrains show an increased drivetrain efficiency, despite increased battery losses. The MMSP topology showed the best result. In comparison to the CHB topology, the battery losses were reduced by the MMSP inverter system.
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| 23. |
- Kersten, Anton, 1991, et al.
(författare)
-
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
-
Ingår i: IEEE Transactions on Power Electronics. - 0885-8993 .- 1941-0107. ; 36:1, s. 378-390
-
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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| 24. |
- Kersten, Anton, 1991
(författare)
-
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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| 25. |
- Kersten, Anton, 1991, et al.
(författare)
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Output voltage synthesis of a modular battery system based on a cascaded h-bridge multilevel inverter topology for vehicle propulsion: Multilevel pulse width modulation vs. fundamental selective harmonic elimination
- 2020
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Ingår i: 2020 IEEE Transportation Electrification Conference and Expo, ITEC 2020. ; , s. 296-302
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Konferensbidrag (refereegranskat)abstract
- Lately, the research interest for modular battery systems has increased due to the possibility of a better utilization of individual battery packs/cells and the steadily reducing costs of low voltage power electronics. This paper deals with the output voltage synthesis of a modular battery system based on a seven level Cascaded H-bridge (CHB) inverter topology used in a small passenger vehicle. Two methods are considered, Multilevel Pulse Width Modulation (MPWM) and Fundamental Selective Harmonic Elimination (FSHE). Using simulations, the inverter and battery losses, as well as the current THD, are used to assess the effectiveness of both techniques for the broad operating range of a vehicle's drivetrain. It has been shown that FSHE cannot be applied at a modulation index below 0.25, because of the high current THD (> > 5%). Exceeding a modulation index of 0.25, FSHE reduces the battery and inverter losses in comparison to MPWM, while maintaining an acceptable current THD. Operating at higher speeds, FSHE achieves an even better current THD than MPWM. Consequently, it seems reasonable to use a hybrid modulation technique, using MPWM at low and FSHE at higher speeds, respectively. The exact boundary between MPWM and FSHE can vary in accordance with the individual optimization weightings of current THD and drivetrain efficiency.
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| 26. |
- Kersten, Anton, 1991, et al.
(författare)
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Rotor Design of a Line-Start Synchronous Reluctance Machine with Respect to Induction Machine for Industrial Applications
- 2018
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Ingår i: Proceedings - 2018 23rd International Conference on Electrical Machines, ICEM 2018. - 9781538624777 ; 24 October 2018, s. 393-399
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Konferensbidrag (refereegranskat)abstract
- This paper introduces a unique rotor design for line-start synchronous reluctance machines. Efficiency and synchronization capability are determined and a comparison between line-start synchronous reluctance machines and induction machines is drawn. For the design and simulation, FEM calculations were used and the results were experimentally verified. Within the frame of this paper a 4 kW rated induction machine with an efficiency class rating of IE3 was chosen as a benchmark motor. The new rotor-cage design of the line start reluctance machine decreases the motor losses at steady state by about 28%. This promising approach could be used to upgrade induction machines in industry environments instead of replacing them. Nevertheless, a challenge in the design is a good balance between the steady state performance and synchronization capability, whereby the range of industrial applications is limited for high efficient line-start synchronous reluctance machines.
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| 27. |
- Kersten, Anton, 1991, et al.
(författare)
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Rotor Design of Line-Start Synchronous Reluctance Machine With Round Bars
- 2019
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Ingår i: IEEE Transactions on Industry Applications. - 0093-9994 .- 1939-9367. ; 55:4, s. 3685-3696
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Tidskriftsartikel (refereegranskat)abstract
- Within the field of industry applications, the induction machine (IM) is the most used motor type, due to its robustness and line-start ability. However, the need to constrain global warming demands new sustainable technologies with high efficiency. Therefore, line-start synchronous reluctance machines could be an opportunity to achieve a high efficiency for several industry applications, especially for constant-speed drives. This paper introduces a unique rotor design for line-start synchronous reluctance machines (LSSynRMs). Additionally, the influence of the rotor bar material/resistance and the stator resistance in comparison to common IMs for industrial applications is investigated. Finite element method calculations were used for the design and the efficiency enhancement was verified using experiments. Within the context of this analysis, a 4-kW-rated IM with an efficiency rating of IE3 was chosen as a benchmark motor. The new rotor-cage design decreases the motor losses at steady state by about 28%. This promising approach could be used to upgrade IMs in industry environments instead of replacing them. Nevertheless, a challenge in the design is a good balance between the steady-state performance and synchronization capability, which in turn limits the range of industrial applications for highly efficient LSSynRMs.
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| 28. |
- Kersten, Anton, 1991, et al.
(författare)
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Sensorless Capacitor Voltage Balancing of a Grid-Tied, Single-Phase Hybrid Multilevel Converter with Asymmetric Capacitor Voltages using Dynamic Programming
- 2020
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Ingår i: IECON Proceedings (Industrial Electronics Conference). - 2162-4704 .- 2577-1647. ; , s. 4288-4293
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Konferensbidrag (refereegranskat)abstract
- This paper shows a sensorless capacitor voltage balancing control approach for a grid-connected, single-phase hybrid multilevel inverter based on an NPC main stage with a voltage stiff DC-link and an arbitrary number of H-Bridge modules (capacitor modules) with asymmetric capacitor voltages. Using nearest-level control, a model predictive control (MPC) approach with a prediction horizon of one time step is chosen to find an optimal switching-state combination among the redundant switching combinations to balance the capacitor voltages as quick as possible. Using the Lyapunov stability criterion, it is shown that an offline calculated optimal switching-state sequence for each discrete output voltage level can be used to operate the inverter without using any voltage sensors for the capacitor voltages. To validate the stability of the approach, a laboratory inverter with a resistive load is operated with the offline calculated optimal switching-state sequences and it is shown that the capacitor voltages converge to their desired reference voltages.
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| 29. |
- Kuder, Manuel, et al.
(författare)
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Battery modular multilevel management (Bm3) converter applied at battery cell level for electric vehicles and energy storages
- 2020
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Ingår i: PCIM Europe Conference Proceedings. - 2191-3358. ; 1, s. 1726-1733
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Konferensbidrag (refereegranskat)abstract
- This paper introduces a modular battery system based on an integrated 3-switch inverter topology, referred to as Battery Modular Multilevel Management (BM3) system. The 3-switch topology can be directly applied on battery cell level. In interconnection with the other battery cells, series and parallel connections can be flexibly formed across the battery modules to synthesize any kind of output voltage. In this manner the BM3 topology can work as a flexible DC/AC or DC/DC converter. Furthermore, individual cells can be bypassed, so that each cell can be charged and drained according to their individual capacity. Thus, any additional passive or active balancing circuitry becomes obsolete. Within the frame of this paper’s analysis, the basic functionality of the BM3 topology is explained and the possible application as a DC/AC inverter is validated using a small scale prototype setup.
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| 30. |
- Kuder, Manuel, et al.
(författare)
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Exponential Modular Multilevel Converter for Low Voltage Applications
- 2019
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Ingår i: 2019 21st European Conference on Power Electronics and Applications, EPE 2019 ECCE Europe. ; , s. 1-11
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Konferensbidrag (refereegranskat)abstract
- This paper presents the structure and control of a single phase Exponential Modular Multilevel Converter (EMMC), which works as a bidirectional AC/DC converter. In addition to the main H-bridge converter, it uses series connected H-bridges with DC link capacitors. The nominal voltage rating of the capacitors is increased with each module by factor of two. In this manner, the number of output voltage levels exponentially increases with the number of series connected H-bridges. By using low-voltage MOSFETs it is possible to achieve a very high efficiency, especially at partial loading. The high number of voltage levels reduces the output voltage THD, while using a low switching frequency. Thus, the required grid filter size can be substantially reduced. Furthermore, the additional capacitor modules increase the nominal output voltage at the AC side, so that the flow of the active and reactive power can be dynamically adjusted. Therefore, the EMMC could be used, for instance, as a vehicle charger directly connected to the grid.
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| 31. |
- 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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| 32. |
- 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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| 33. |
- 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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| 34. |
- 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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| 35. |
- 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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| 36. |
- Theliander, Oskar, et al.
(författare)
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Battery Modeling and Parameter Extraction for Drive Cycle Loss Evaluation of a Modular Battery System for Vehicles Based on a Cascaded H-Bridge Multilevel Inverter
- 2020
-
Ingår i: IEEE Transactions on Industry Applications. - 0093-9994 .- 1939-9367. ; 56:6, s. 6968-6977
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Tidskriftsartikel (refereegranskat)abstract
- This article deals with the modeling and the parameterization of the battery packs used in cascaded H-bridge multilevel propulsion inverters. Since the battery packs are intermittently conducting the motor currents, the battery cells are stressed with a dynamic current containing a substantial amount of low-order harmonic components up to a couple of kHz, which is a major difference in comparison to a traditional two-level inverter drive. Different models, such as pure resistive and dynamic RC -networks, are considered to model the energy losses for different operating points (OPs) and driving cycles. Using a small-scale setup, the models’ parameters are extracted using both a low-frequency, pulsed current, and an electrochemical impedance spectroscopy (EIS) sweep. The models are compared against measurements conducted on the small-scale setup at different OPs. Additionally, a drive cycle loss comparison is simulated. The simple resistive model overestimates the losses by about 20% and is, thus, not suitable. The dynamic three-time-constant model, parameterized by a pulsed current, complies with the measurements for all analyzed OPs, especially at low speed, with a maximum deviation of 3.8%. Extracting the parameters using an EIS seems suitable for higher speeds, though the losses for the chosen OPs are underestimated by 1.5%–7.9%.
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| 37. |
- Theliander, Oskar, et al.
(författare)
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LiFePO4 Battery Modeling and Drive Cycle Loss Evaluation in Cascaded H-Bridge Inverters for Vehicles
- 2019
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Ingår i: ITEC 2019 - 2019 IEEE Transportation Electrification Conference and Expo. ; June 2019, s. 1-7
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Konferensbidrag (refereegranskat)abstract
- This paper deals with the modeling and parameterization of LiFeP04batteries when used in cascaded H-bridge multilevel inverter drive systems. Since the battery packs are intermittently conducting the motor currents, the battery cells are stressed with a dynamic current waveform containing a substantial amount of low order harmonic components in the range of a couple of kHz. Different battery models like a pure resistive or different RC networks are considered, to determine the battery losses. Measurements of the voltage drop for a pulsed current of variable frequency and magnitude are done to be able to determine the model parameters. The models are then verified against measurements on a battery pack placed in a small scale multilevel inverter operated at 6 different operating point that are representative for the operation of an electrified vehicle. It is shown that the dynamic model agrees very well with the measurements for all operating points analyzed with a maximum deviation of 4 %. The results are also compared with the commonly used resistive model which overestimates the losses with typically around 20 % for the evaluated points. Simulations of 4 full drive cycles are performed where it is stated that the resistive model always shows about 20 % more losses compared to the 3 time constant model.
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| 38. |
- Xu, Yu, 1996, et al.
(författare)
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Comparative study of efficiency improvement with adjustable DC-link voltage powertrain using DC-DC converter and Quasi-Z-Source inverter
- 2023
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Ingår i: 2023 IEEE Conference and Expo Transportation Electrification Asia-Pacific (ITEC Asia-Pacific). - 9798350314274
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Konferensbidrag (refereegranskat)abstract
- Adjusting the DC-link voltage in the electric pow-ertrain has proven to be beneficial for enhancing powertrain efficiency. This paper presents a comparative study between two adjustable DC-link voltage powertrain solutions: (1) Voltage Source Inverter (VSI) integrated with a DC-DC converter (VSI+DC-DC) and (2) Quasi-Z-Source Inverter (QZSI). Based on the different operation principles of the two solutions, DC-link voltage adjustment strategies have been proposed to maximize powertrain efficiency over drive cycle operation. With the help of simulation in the PLECS environment, the powertrain losses of the two solutions are examined over the WLTC drive cycle. The results suggest both solutions can achieve significant powertrain loss reduction compared to the conventional powertrain with fixed DC-link voltage. In addition, the QZSI solution sees a 20% higher loss in power electronics than the VSI+DC-DC solution, as the DC-link voltage in the QZSI solution has to be boosted to higher values. Nevertheless, from an overall powertrain perspective, the QZSI solution has only 3% higher powertrain losses compared to the VSI+DC-DC solution, making QZSI remain an attractive alternative for adjustable DC-link powertrain given its advantages such as fewer active switches and improved system reliability.
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| 39. |
- Xu, Yu, 1996, et al.
(författare)
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Improved efficiency with adaptive front and rear axle independently driven powertrain and disconnect functionality
- 2023
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Ingår i: Transportation Engineering. - 2666-691X. ; 13
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Tidskriftsartikel (refereegranskat)abstract
- Front and rear axle independently driven (FRID) powertrains are becoming a popular solution for electric vehicles (EVs) due to torque distribution capability which can enhance powertrain energy efficiency. Typically, permanent magnet synchronous machines (PMSMs) are used for FRID powertrains due to their high torque, and power density. However, the drive-cycle efficiency of FRID powertrains with PMSMs is typically reduced in comparison to single motor drives. This is due to the unwanted no-load losses of PMSMs in the field weakening region. To overcome this drawback of PMSM FRIDs, this paper proposes an adaptive front- and rear-axle independently driven (AFRID) powertrain, utilizing two dog clutches, so that the powertrain can be operated in different modes (rear, front, and all-wheel drive) by adaptively connecting and disconnecting the front and/or rear electric drive unit (EDU). A rule-based mode selection strategy is developed to utilize the flexibility of different powertrain operating modes of the powertrain for maximizing the energy efficiency of the EDU. The simulation results show that the suggested AFRID powertrain, in comparison to a common FRID powertrain, can improve the WLTC drive-cycle consumption from 22.17 kWhh to 20.50 kWhh per 100 km. Based on the route and road-load information, the energy-saving potential of the AFRID powertrain can be further improved to 20.37 kWhh per 100 km by a suggested predictive mode selection strategy, achieving an optimal mode selection.
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| 40. |
- Xu, Yu, 1996, et al.
(författare)
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Maximizing Efficiency in Smart Adjustable DC Link Powertrains with IGBTs and SiC MOSFETs via Optimized DC-Link Voltage Control
- 2023
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Ingår i: Batteries. - 2313-0105. ; 9:6
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Tidskriftsartikel (refereegranskat)abstract
- In recent years, the push towards electrifying transportation has gained significant traction, with battery-electric vehicles (BEVs) emerging as a viable alternative. However, the widespread adoption of BEVs faces multiple challenges, such as limited driving range, making powertrain efficiency improvements crucial. One approach to improve powertrain energy efficiency is to adjust the DC-link voltage using a DC-DC converter between the battery and inverter. Here, it is necessary to address the losses introduced by the DC-DC converter. This paper presents a dynamic programming approach to optimize the DC-link voltage, taking into account the battery terminal voltage variation and its impact on the overall powertrain losses. We also examine the energy efficiency gains of IGBT-based and silicon carbide (SiC) MOSFET-based adjustable DC-link voltage powertrains during WLTC driving cycles through PLECS and Matlab/Simulink simulations. The findings indicate that both IGBT and MOSFET-based adjustable DC-link voltage powertrains can enhance the WLTC drive-cycle efficiency up to 2.51%2.51% and 3.25%3.25% compared to conventional IGBT and MOSFET-based powertrains, respectively.
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