The Experts below are selected from a list of 25443 Experts worldwide ranked by ideXlab platform
Michael A E Andersen - One of the best experts on this subject based on the ideXlab platform.
-
an improved partially interleaved transformer structure for high voltage high frequency multiple output applications
IEEE Transactions on Industrial Electronics, 2019Co-Authors: Bin Zhao, Michael A E Andersen, Ziwei Ouyang, Maeve Duffy, W G HurleyAbstract:This paper proposes an improved partially interleaved structure for high-voltage (several kV) high-frequency (several hundred kHz) multiple-output applications. The proposed transformer structure is compared with other typical structures with the leakage inductance, Ac capAcitance, Ac Resistance, and the ratio of Ac–dc Resistance taken into consideration. The proposed structure features lower leakage inductance, smaller Ac capAcitance, lower Ac Resistance, and lower ratio of Ac–dc Resistance, which is suitable for high-frequency high-efficiency applications. A planar transformer with the proposed structure was built and tested in an LCLC resonant converter, where the input voltage is 40 V, the output is 4800 V, the switching frequency is 500 kHz, the output power is 288 W, and the efficiency is 96.8%, which validates the analysis.
-
investigation of transformer winding architectures for high voltage 2 5 kv capAcitor charging and discharging applications
IEEE Transactions on Power Electronics, 2016Co-Authors: Prasanth Thummala, Henrik Schneider, Zhe Zhang, Michael A E AndersenAbstract:Transformer parasitics such as leakage inductance and self-capAcitance are rarely calculated in advance during the design phase, because of the complexity and huge analytical error margins caused by prActical winding implementation issues. Thus, choosing one transformer architecture over another for a given design is usually based on experience or a trial and error approAch. This paper presents analytical expressions for calculating leakage inductance, self-capAcitance, and Ac Resistance in transformer winding architectures (TWAs), ranging from the common noninterleaved primary/secondary winding architecture, to an interleaved, sectionalized, and bank winded architecture. The calculated results are evaluated experimentally, and through finite-element simulations, for an RM8 transformer with a turns ratio of 10. The four TWAs such as, noninterleaved and nonsectioned, noninterleaved and sectioned, interleaved and nonsectioned, and interleaved and sectioned, for an EF25 transformer with a turns ratio of 20, are investigated and prActically implemented. The best TWA for an RM8 transformer in a high-voltage bidirectional flybAck converter, used to drive an electro Active polymer based incremental Actuator, is identified based on the losses caused by the transformer parasitics. For an EF25 transformer, the best TWA is chosen According to whether electromagnetic interference due to the transformer interwinding capAcitance, is a major problem or not.
-
high current planar transformer for very high efficiency isolated boost dc dc converters
Power Electronics Conference (IPEC-Hiroshima 2014 - ECCE-ASIA) 2014 International, 2014Co-Authors: Riccardo Pittini, Zhe Zhang, Michael A E AndersenAbstract:This paper presents a design and optimization of a high current planar transformer for very high efficiency dc-dc isolated boost converters. The analysis considers different winding arrangements, including very high copper thickness windings. The analysis is focused on the winding Ac-Resistance and transformer leakage inductance. Design and optimization procedures are validated based on an experimental prototype of a 6 kW dc-dc isolated full bridge boost converter developed on fully planar magnetics. The prototype is rated at 30-80 V 0-80 A on the low voltage side and 700-800 V on the high voltage side with a peak efficiency of 97.8% at 80 V 3.5 kW. Results highlights that thick copper windings can provide good performance at low switching frequencies due to the high transformer filling fActor. PCB windings can also provide very high efficiency if stAcked in parallel utilizing the transformer winding window in an optimal way.
-
hybrid winding concept for toroids
IEEE ECCE Asia Downunder, 2013Co-Authors: Henrik Schneider, Thomas Andersen, Arnold Knott, Michael A E AndersenAbstract:This paper proposes a hybrid winding concept for toroids using the trAces in a printed circuit board to make connection to bended copper foil cutouts. In a final product a number of strips with a certain thickness would be held by a former and the whole assembly could be plAced by pick and plAcement mAchinery. This opens up the possibility for both an automated manufActuring process and an automated production process of toroidal magnetics such as power inductors, filtering inductors, air core inductors, transformers etc. Both the proposed hybrid and the common wire wound winding implementation is simulated using finite element modeling and the DC and Ac Resistance of the inductors are verified with experimental measurements on prototypes. It is found that commercial available layer thickness of printed circuit boards is a bottleneck for high power applications. Furthermore, the winding configuration is crucial for performance.
-
printed circuit board embedded inductors for very high frequency switch mode power supplies
IEEE ECCE Asia Downunder, 2013Co-Authors: Mickey Pierre Madsen, Michael A E Andersen, Arnold Knott, Anders P MynsterAbstract:The paper describes the design of three different structures for printed circuit board embedded inductors. Direct comparison of spirals, solenoids and toroids are made with regard to inductance, dc and Ac Resistance, electromagnetic field and design flexibility. First the equations for the impedances are given and an example of the Achievable impedances are given. Prototypes are then made and measured. The differences between the three structures and the AccurAcy of the formulas are evaluated. Finite element simulations are used to investigate the magnetic field around the structure, in order to take possible electromagnetic interference problems into Account, when the structures are compared. The simulated fields are verified through near field measurements performed on the prototypes. Finally deign flexibility are considered, both regarding scalability and design of the individual inductors and implementation in a complete design. At the end of the paper a summary of pros and cons of the three structures are listed.
Juha Pyrhonen - One of the best experts on this subject based on the ideXlab platform.
-
Thermal Analysis of the Laminated Busbar System of a Multilevel Converter
IEEE Transactions on Power Electronics, 2016Co-Authors: Liudmila Smirnova, Raimo Juntunen, Kirill Murashko, Tatu Musikka, Juha PyrhonenAbstract:Laminated busbar systems are commonly used in power electronic converters because of their low stray inductance. While the electromagnetic analysis of a busbar system is widely presented in the literature, there is a lAck of Accurate thermal modeling. In this paper, the thermal analysis of the busbar system is presented. An analytical lumped parameter thermal model (LPTM) of the busbar system is developed. The LPTM is applied to the fast estimation of the mean temperature and temperature-dependent power losses of the busbars by the proposed algorithm. Joule losses produced by nonsinusoidal currents flowing through the busbars in the converter are estimated. The skin and proximity effects, which have a strong influence on the Ac Resistance of the busbars, are considered in the loss estimation. Thus, a comprehensive electrothermal model of the busbar system is developed, which is of prActical use in the converter design. It allows optimizing the stray inductance, material consumption, and cost of the busbar system as long as the specified temperature limits are not exceeded. The finite-element method thermal modeling validates the developed LPTM. Laboratory measurements in two operating points of the converter have been performed, and they show good correlation with the simulation results.
-
Ac Resistance fActor of litz wire windings used in low voltage high power generators
IEEE Transactions on Industrial Electronics, 2014Co-Authors: Henry Hamalainen, Juha Pyrhonen, Janne Nerg, J TalvitieAbstract:New types of heavy litz wires with noninsulated or insulated strands are offered for high-power low-voltage electrical mAchines, where skin and proximity effects can cause serious problems if traditional windings are used. This paper evaluates the Ac Resistance of a litz wire and its usability in megawatt-range low-voltage electrical mAchines. The evaluation is made by finite-element analysis and by Resistance measurements with an experimental test setup. A simple amplifier configuration was used to minimize current and voltage phase shift errors, which are critical in this kind of low-impedance and low-frequency measurement. A simple measurement device based on the aforementioned configuration was prepared to ensure a precise measurement result. Tests were done in a frequency range of 50-200 Hz, to cover a wide range of prActical high-power low-voltage electrical mAchines. It is found that the measured litz wire with originally noninsulated strands can be used in large electrical mAchines up to about 120 Hz if about 50% increase in Ac Resistance compared to the dc Resistance is allowed. Impregnation of the originally noninsulated litz wire with vAcuum pressure impregnation improved the Ac Resistance in one test case, and in the other case, it seemed to have no effect on the Ac Resistance.
-
Ac Resistance fActor in one layer form wound winding used in rotating electrical mAchines
IEEE Transactions on Magnetics, 2013Co-Authors: Henry Hamalainen, Juha Pyrhonen, Janne NergAbstract:Analytical calculation of circulating and eddy currents in windings has been under research for almost a century, yet the calculation AccurAcy has improved slowly. However, over the recent years, the development of finite-element methods (FEM) has boosted the research. A lot of effort has been taken to calculate the Ac Resistance losses in transformers in the past, whereas rotating electrical mAchines have received less attention. These models have not taken the end-winding effect into Account. In this paper, 2-D FEM results are compared with analytical equations. Based on these results, a more Accurate model compared with Dowell's model for single-layer form-wound windings used in electrical mAchines is developed empirically, and the end winding Resistance is analytically taken into Account in the results. A maximum error of 5% is Achieved in the range of 0–200 Hz for a single-layer form-wound winding.
Ziwei Ouyang - One of the best experts on this subject based on the ideXlab platform.
-
an improved partially interleaved transformer structure for high voltage high frequency multiple output applications
IEEE Transactions on Industrial Electronics, 2019Co-Authors: Bin Zhao, Michael A E Andersen, Ziwei Ouyang, Maeve Duffy, W G HurleyAbstract:This paper proposes an improved partially interleaved structure for high-voltage (several kV) high-frequency (several hundred kHz) multiple-output applications. The proposed transformer structure is compared with other typical structures with the leakage inductance, Ac capAcitance, Ac Resistance, and the ratio of Ac–dc Resistance taken into consideration. The proposed structure features lower leakage inductance, smaller Ac capAcitance, lower Ac Resistance, and lower ratio of Ac–dc Resistance, which is suitable for high-frequency high-efficiency applications. A planar transformer with the proposed structure was built and tested in an LCLC resonant converter, where the input voltage is 40 V, the output is 4800 V, the switching frequency is 500 kHz, the output power is 288 W, and the efficiency is 96.8%, which validates the analysis.
-
optimal design and tradeoff analysis of planar transformer in high power dc dc converters
IEEE Transactions on Industrial Electronics, 2012Co-Authors: Ziwei Ouyang, Ole C Thomsen, Michael A E AndersenAbstract:The trend toward high power density, high operating frequency, and low profile in power converters has exposed a number of limitations in the use of conventional wire-wound magnetic component structures. A planar magnetic is a low-profile transformer or inductor utilizing planar windings, instead of the traditional windings made of Cu wires. In this paper, the most important fActors for planar transformer (PT) design including winding loss, core loss, leakage inductance, and stray capAcitance have individually been investigated. The tradeoffs among these fActors have to be analyzed in order to Achieve optimal parameters. Combined with an application, four typical winding arrangements have been compared to illustrate their advantages and disadvantages. An improved interleaving structure with optimal behaviors is proposed, which constructs the top layer paralleling with the bottom layer and then in series with the other turns of the primary, so that a lower magnetomotive force ratio m can be obtained, as well as minimized Ac Resistance, leakage inductance, and even stray capAcitance. A 1.2-kW full-bridge dc-dc converter prototype employing the improved PT structure has been constructed, over 96% efficiency is Achieved, and a 2.7% improvement, compared with the noninterleaving structure, is obtained.
-
analysis of planar e i and er i transformers for low voltage high current dc dc converters with focus on winding losses and leakage inductance
International Power Electronics and Motion Control Conference, 2012Co-Authors: Riccardo Pittini, Michael A E Andersen, Ziwei Ouyang, Zhe Zhang, Ole C ThomsenAbstract:In this paper an analysis of two planar transformers designed for high-current switching applications is presented. Typical converter application is represented by fuel and electrolyser cell converters. The transformer designs are based on E+I and ER+I planar cores while the analysis focuses on winding Resistance and leakage inductances which represent the main concerns related to low-voltage high-current applications. The PCB winding design has a one to one turn ratio with no interleaving between primary and secondary windings. The main goal was to determine if ER planar core could provide a significant advantage in terms of winding losses compared to planar E cores. Results from finite element analysis highlight that low frequency winding Resistance is lower for the ER core since it is dominated by the lower mean turn length however, as the Ac-Resistance becomes dominating the winding eddy current losses increases more in the ER core than in the E core design. Calculated and simulated leakage inductances for the analyzed cores do not show relevant differences. A laboratory prototype based on E64 planar core is used as reference. Laboratory measurements highlight that FEM analysis provides more realistic results when computing the winding Ac-Resistance.
Daocheng Huang - One of the best experts on this subject based on the ideXlab platform.
-
llc resonant converter with matrix transformer
IEEE Transactions on Power Electronics, 2014Co-Authors: F C Lee, Daocheng HuangAbstract:In this paper, a high-efficiency high power density LLC resonant converter with a matrix transformer is proposed. A matrix transformer can help reduce leakage inductance and the Ac Resistance of windings so that the flux cancellation method can then be utilized to reduce core size and loss. Synchronous rectifier (SR) devices and output capAcitors are integrated into the secondary windings to eliminate termination-related winding losses, via loss and reduce leakage inductance. A 1 MHz 390 V/12 V 1 kW LLC resonant converter prototype is built to verify the proposed structure. The efficiency can reAch as high as 95.4%, and the power density of the power stage is around 830 W/in3.
-
llc resonant converter with matrix transformer
Applied Power Electronics Conference, 2014Co-Authors: Daocheng Huang, F C LeeAbstract:In this paper, a high efficiency high power density matrix transformer structure for LLC resonant converters is proposed. Matrix transformer is help to reduce leakage inductance and the Ac Resistance of windings. Flux cancellation method is utilized to reduce core size and loss. Synchronous Rectifier (SR) devices and output capAcitors are integrated into secondary windings to eliminate termination related winding losses, via loss and leakage inductance. A detail design procedure is proposed. A 1MHz 390V /12 V 1kW LLC resonant converter prototype is built.
Henry Hamalainen - One of the best experts on this subject based on the ideXlab platform.
-
Ac Resistance fActor of litz wire windings used in low voltage high power generators
IEEE Transactions on Industrial Electronics, 2014Co-Authors: Henry Hamalainen, Juha Pyrhonen, Janne Nerg, J TalvitieAbstract:New types of heavy litz wires with noninsulated or insulated strands are offered for high-power low-voltage electrical mAchines, where skin and proximity effects can cause serious problems if traditional windings are used. This paper evaluates the Ac Resistance of a litz wire and its usability in megawatt-range low-voltage electrical mAchines. The evaluation is made by finite-element analysis and by Resistance measurements with an experimental test setup. A simple amplifier configuration was used to minimize current and voltage phase shift errors, which are critical in this kind of low-impedance and low-frequency measurement. A simple measurement device based on the aforementioned configuration was prepared to ensure a precise measurement result. Tests were done in a frequency range of 50-200 Hz, to cover a wide range of prActical high-power low-voltage electrical mAchines. It is found that the measured litz wire with originally noninsulated strands can be used in large electrical mAchines up to about 120 Hz if about 50% increase in Ac Resistance compared to the dc Resistance is allowed. Impregnation of the originally noninsulated litz wire with vAcuum pressure impregnation improved the Ac Resistance in one test case, and in the other case, it seemed to have no effect on the Ac Resistance.
-
Ac Resistance fActor in one layer form wound winding used in rotating electrical mAchines
IEEE Transactions on Magnetics, 2013Co-Authors: Henry Hamalainen, Juha Pyrhonen, Janne NergAbstract:Analytical calculation of circulating and eddy currents in windings has been under research for almost a century, yet the calculation AccurAcy has improved slowly. However, over the recent years, the development of finite-element methods (FEM) has boosted the research. A lot of effort has been taken to calculate the Ac Resistance losses in transformers in the past, whereas rotating electrical mAchines have received less attention. These models have not taken the end-winding effect into Account. In this paper, 2-D FEM results are compared with analytical equations. Based on these results, a more Accurate model compared with Dowell's model for single-layer form-wound windings used in electrical mAchines is developed empirically, and the end winding Resistance is analytically taken into Account in the results. A maximum error of 5% is Achieved in the range of 0–200 Hz for a single-layer form-wound winding.
