14 results on '"Biela, Jurgen"'
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2. Frequency-Dependent Inductance and Winding Loss Model for Gapped Foil Inductors.
- Author
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Ewald, Thomas and Biela, Jurgen
- Subjects
- *
ELECTRIC inductance , *EDDY current losses , *SOLENOIDS , *MAGNETIC fields - Abstract
For comprehensively optimizing high-frequency foil inductors, calculating the increased inductance and the additional eddy current losses due to a two-dimensional magnetic fringing field caused by air gaps in the center leg is mandatory. This article proposes an analytical model that accurately calculates the inductance and the additional eddy current losses in gapped inductors with foil windings. The analytical field expressions are combined into closed-form winding loss and inductance formulas and verified by measurements. Furthermore, the frequency dependency of the inductance due to the shielding effect of the foil conductors is being discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
3. Eddy Current Loss Model for Ferrite Ring Cores Based on a Meta-Material Model of the Core Properties.
- Author
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Dimier, Theophane and Biela, Jurgen
- Subjects
- *
EDDY currents (Electric) , *EDDY current losses , *FERRITES , *WAVE equation , *MAGNETIC cores - Abstract
A model for estimating the total eddy current losses in ring ferrite cores is proposed, which is based on a microstructure model of the electrical parameters of the material (conductivity and permittivity) and on the solution of the wave equations in the core. The presented model, combined with state-of-the-art estimation of the hysteresis losses, gives good agreement with the core loss measurements, over a wide range of frequencies (10–700 kHz). [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
4. Comparison of Analytical Models of Transformer Leakage Inductance: Accuracy Versus Computational Effort.
- Author
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Schlesinger, Richard and Biela, Jurgen
- Subjects
- *
ELECTRIC inductance , *LEAKAGE , *PERMEABILITY - Abstract
A fast and accurate model of the transformer leakage inductance is crucial for optimization-based design of galvanically isolated converters. Analytical models are fastly executable, and therefore, especially suitable for such optimizations. This article compares several analytical leakage inductance per unit length models with respect to the accuracy and computational effort. The considered models are applicable to E-Core and U-Core transformers. 2D FEM simulations are used as a benchmark to evaluate the model accuracy, whereas the computation time is extracted as an indicator for computational effort. Six different transformer prototypes provide the geometries for the comparison. Based on the conducted comparisons, Roth's model is the most accurate. Rogowski's model is the fastest low-error model. Margueron's model is the most versatile as it takes the finite permeability of the core into account. The conducted comparisons lay the foundation for accurate and fast Double-2D modeling of the transformer leakage inductance as it is executed for the two main cross sections of E-core and U-core transformers: inside the transformer window, and outside the transformer window. This article is accompanied by a supplementary document summarizing the equations of Roth's and Margueron's model. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
5. Design of a Protection Concept for a 100-kVA Hybrid Transformer.
- Author
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Burkard, Johannes and Biela, Jurgen
- Subjects
- *
DESIGN protection , *REACTIVE power , *SHORT circuits , *OVERCURRENT protection , *ELECTRIC power distribution grids , *VOLTAGE control - Abstract
Due to the increasing integration of renewable energies into the distribution grid, a deterioration of the grid power quality is expected. Consisting of a low-frequency transformer and a fractionally rated power electronic converter, hybrid transformers (HTs) can be applied to ensure a high power quality by controlling voltage, active and reactive power dynamically. For the application in conventional grids, HTs have to withstand considerable overvoltages and overcurrents during voltage surges or short circuits. Although HTs recently gained increasing research interest, protection requirements and protection concepts have not been discussed yet. These aspects are, however, essential to evaluate the practical potential of HTs. In this article, protection requirements are derived and a protection concept is developed and verified by simulations and experiments for a 100-kVA hybrid distribution transformer. Although the protection concept has a considerable impact on the design and performance of the converter, it increases the total losses and volume of the HT only insignificantly. An efficiency of 98.48% is achievable for an HT including protection, which is only slightly lower than the efficiency of 98.64% for a comparable conventional transformer. This renders the HT a promising solution for today's and future ac grids. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
6. Analytical Switching Loss Modeling Based on Datasheet Parameters for mosfets in a Half-Bridge.
- Author
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Christen, Daniel and Biela, Jurgen
- Subjects
- *
SEMICONDUCTOR devices - Abstract
Modern wide-bandgap devices, such as SiC- or GaN-based devices, feature significantly reduced switching losses, and the question arises if soft-switching operating modes are still beneficial. For most of the semiconductor devices, only limited information is available to estimate the switching losses. Especially, if a wide operating range is desired, excessive measurements have to be performed to determine the switching losses for arbitrary operating points. Therefore, in this paper, a fast calculation method to determine the switching losses based on the charge equivalent approximation of the mosfet capacitances, relying only on datasheet parameters, is presented. In addition, the turn-off losses at high switching currents are investigated, and an analytical expression to estimate the maximum current range for which the mosfet can be turned off with negligible switching losses is proposed. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
7. PV-Module-Integrated AC Inverters (AC Modules) With Subpanel MPP Tracking.
- Author
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Leuenberger, David and Biela, Jurgen
- Subjects
- *
ELECTRIC inverters , *MAXIMUM power point trackers , *DC-to-DC converters , *PHOTOVOLTAIC power systems , *GALLIUM nitride - Abstract
For small scale roof-top systems, there is a trend towards module-integrated electronics. Module integrated ac inverters (ac modules) connect each photovoltaic (PV) module separately to the single-phase grid. They feature not only increased yield due to module-level maximum power point (MPP) tracking, but also further advantages such as reduced installation cost. This work investigates the concept of subpanel-level MPP tracking for ac modules, which allows us to increase yield thanks to reduced mismatching losses. Topology concepts to realize such a converter are systematically investigated and categorized. A topology comparison identifies two promising system concepts: first a single-stage converter with a three-port power balancer and second a two-stage topology with three paralleled dc–dc converters and a pulse width modulation full bridge. The later features the advantage of a small power-decoupling capacitor and is therefore further investigated. A model-based optimization of the investigated multi-input ac module is performed, applying high performing Gallium Nitride (GaN) devices and nanocrystalline core materials to increase efficiency. The built prototype confirms the accuracy of the model-based optimization. The performed efficiency study reveals an achievable efficiency of \eta \text{EU} = 94.5%. In order to compete with single-input ac modules, achieving typically an efficiency of 95.5%, the efficiency of multi-input ac modules must improve beyond the level achieved with the investigated two-stage ac-module topology. Given this result, the alternative system concept with a three-port power balancer in combination with a single-stage converter seems to be more promising, as it is conceptually similar to the high efficient single-input ac modules and may achieve the same high efficiency. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
8. Combined Phase-Shift and Frequency Modulation of a Dual-Active-Bridge AC–DC Converter With PFC.
- Author
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Jauch, Felix and Biela, Jurgen
- Subjects
- *
FREQUENCY modulation detectors , *AC DC transformers , *CONVERTERS (Electronics) , *ELECTRIC switchgear , *ZERO voltage switching , *ELECTRIC power factor , *COMMUTATION (Electricity) - Abstract
This paper presents a combined phase-shift and frequency modulation scheme of a dual–active-bridge (DAB) ac–dc converter with power factor correction (PFC) to achieve zero voltage switching (ZVS) over the full range of the ac mains voltage. The DAB consists of a half bridge with bidirectional switches on the ac side and a full bridge on the dc side of the isolation transformer to accomplish single-stage power conversion. The modulation scheme is described by means of analytical formulas, which are used in an optimization procedure to determine the optimal control variables for minimum switch commutation currents. Furthermore, an ac current controller suitable for the proposed modulation scheme is described. A loss model and measurements on a 3.3-kW electric vehicle battery charger to connect to the 230 \textV_\textrms / 50-Hz mains considering a battery voltage range of 280–420 V validate the theoretical analysis. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
9. A Three-Level Buck Converter With a Wide Voltage Operation Range for Hardware-in-the-Loop Test Systems.
- Author
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Carstensen, Christoph and Biela, Jurgen
- Subjects
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ELECTRIC controllers , *HARDWARE-in-the-loop simulation , *HIGH-voltage direct current transmission , *ELECTRIC potential , *ELECTRONIC modulation - Abstract
Hardware-in-the-Loop tests of components for high-voltage dc transmission grids, for example circuit breakers, require converter systems capable of generating a high output current with fast transients of the output signal at different output voltages. In this paper, a three-level buck converter (N3L) employing three different supply voltages to enable a wide voltage operation range is presented. The modulation of the converter is investigated in detail with special focus on ripple cancellation, the startup of the interleaved converter and the level shifting between different converter output voltages. A prototype system is designed and constructed, optimized for pulsed power operation and compared to a two level and to a neutral point clamped converter design. The system has been simulated numerically and the design boundaries are validated by measurements on the prototype system. [ABSTRACT FROM AUTHOR]
- Published
- 2016
- Full Text
- View/download PDF
10. Optimization and Performance Evaluation of an AC-Chopper Ballast for HPS Lamps.
- Author
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Giezendanner, Florian, Biela, Jurgen, and Kolar, Johann W.
- Subjects
- *
BALLASTS (Electricity) , *ELECTRIC lamps , *ELECTROMAGNETIC compatibility , *TOPOLOGY , *ELECTRIC lighting , *ELECTRIC controllers - Abstract
Electronic ballasts for high-pressure sodium lamps based on an ac-chopper topology are proposed as a cheaper and less complex alternative to the industry-standard low-frequency square-wave ballasts. In this paper, the design process of the ac-chopper ballast is reviewed, and the design tradeoffs caused by the single-stage topology are discussed. The analytical and simulation results are verified with measurements of a 250-W prototype system, including a detailed list of the losses for the different circuit components and electromagnetic compatibility measurements. Due to the disadvantages of the single-stage topology, a comparison to a two-stage ballast using the inverter stage of the ac-chopper ballast with a separate power factor correction stage is provided. [ABSTRACT FROM PUBLISHER]
- Published
- 2014
- Full Text
- View/download PDF
11. Novel Concepts for Integrating the Electric Drive and Auxiliary DC-DC converter for Hybrid Vehicles.
- Author
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Plesko, Hanna, Biela, Jurgen, Luomi, Jorma, and Kolar, Johann W.
- Subjects
- *
HYBRID electric vehicles , *COST effectiveness , *AIR quality , *ELECTRIC power systems , *MOTOR fuels , *DC-to-DC converters - Abstract
Cost, volume, and weight are three major driving forces in the automotive area. This is also true for hybrid electric vehicles, which are attracting more and more attention due to increasing fuel costs and air pollution. In hybrid vehicles, the energy distribution system causes a significant share of the volume and the costs. One part of this system is the dc-dc converter that transfers power between the low- and high-voltage buses. In order to reduce the costs and the volume of this converter, this paper presents a new concept for integrating the dc-dc converter functionality into the traction drive system. By using the inverter and the machine to implement a primary bridge leg of an isolated full-bridge dc-dc converter, the total system costs and weight can be reduced. This concept is verified by simulations and experimental results for a scaled prototype. An analytical model of the system has been developed and agrees very well with the measurements. By scaling this model to the power levels typical for hybrid vehicles, it is expected that the efficiency for the dc-dc converter will be greater than 85% for a conventional modulation scheme and above 91% for an optimized switching scheme. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
12. Analysis and Reduction of the Output Voltage Error of PWM for Modular Multilevel Converters.
- Author
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Fuchs, Simon, Beck, Simon, and Biela, Jurgen
- Subjects
- *
PULSE width modulation , *VOLTAGE control , *ELECTRIC potential measurement , *SEMICONDUCTOR devices , *CLOSED loop systems - Abstract
Standard pulsewidth modulation (PWM) schemes for modular multilevel converters (MMC) have neglected deviations of the module voltages from the mean module voltage of an MMC arm as well as the dynamic change in the module voltages since their last measurement and during the switching period. This induces an output voltage error. Large output voltage errors disturb the higher level closed-loop control of the MMC, such that control targets cannot be met anymore. The output voltage error can be reduced using advanced PWM methods that predict and include the dynamic change of the individual module voltages during a switching period in the calculations for the duty cycle. This paper shows measurement results obtained from an experimental medium-voltage prototype, proving that advanced methods lead to much lower output voltage errors than the standard methods, but cannot fulfill the expectations raised by the simulations documented in the literature. In order to overcome the limitations of the old method, a new method that includes the semiconductor voltage drop and parasitic resistances is introduced and evaluated with measurements in this paper. Furthermore, simulation results showing the influence of the considered modulation methods on the closed-loop current control performance are presented. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
13. Design procedure of a 14.4 kV, 100 kHz transformer with a high isolation voltage (115 kV).
- Author
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Jaritz, Michael, Blume, Sebastian, and Biela, Jurgen
- Subjects
- *
HIGH voltages , *POWER transformer insulation , *INSULATING oils , *ELECTRIC fields , *PARTIAL discharge measurement , *HIGH frequency transformers - Abstract
In this paper, the design procedure of a 14.4 kV output voltage, 100 kHz transformer with an isolation voltage of 115 kV using Litz wire is presented. All design models, including a generalized magnetic model for the leakage and the loss calculations as well as an electrical model for the parasitic capacitance estimation for the transformer are derived and proven by measurements. For designing the insulation, a comprehensive design method based on an analytical maximum electrical field evaluation and an electrical field conform design is used. The resulting design is verified by long and short term partial discharge measurements on a prototype transformer. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
14. Single Plastic Optical Fiber, Multiple Channel Data Link for Sensing Applications With PCB Implemented Transmitter and Receiver.
- Author
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Fuchs, Simon, Pritz, Michael, Tsolaridis, Georgios, Jehle, Andreas, and Biela, Jurgen
- Subjects
- *
PLASTIC optical fibers , *PULSE amplitude modulation , *PRINTED circuits , *TRANSMITTERS (Communication) - Abstract
The limited physical bandwidth of optical data links can be utilised better using pulse amplitude modulation (PAM) schemes. PAM can also be used to implement multiple channels on a single fibre to reduce the fibre count. In this paper, PAM is used with an additional amplitude level transmitting the clock associated with the data. This allows a direct detection of the clock from the signal. Frequent returns to this additional peak level are used to determine the signal strength at the receiver. The paper presents a very compact PCB implemented transmitter achieving a data rate of up to 400 Mbps. Furthermore, three PCB implemented receiver designs that cover different speed (20-400 Mbps) and cost/complexity ranges are presented including measurement results. The proposed solutions are compared to various industry standard solutions in terms of their achievable sampling rate and measurement delay resulting from connected sensors. It is concluded that PAM based data links represent an attractive alternative to the usual time domain multiplexing based 8b/10b encoded no-return-to-zero (NRZ) data links. They lead to an increase of the possible sampling rate (278%) of the sensor and a decrease of the measurement delay (20%), while keeping the same signal bandwidth and number of fibres. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
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