The Experts below are selected from a list of 27144 Experts worldwide ranked by ideXlab platform
K. Harada - One of the best experts on this subject based on the ideXlab platform.
-
A novel self-excited forward DC-DC converter with zero-voltage-switched Resonant Transitions using a saturable core
IEEE Transactions on Power Electronics, 1995Co-Authors: K. HaradaAbstract:A novel self-excited forward DC-DC power converter is proposed. The turn-on and turn-off of the switch are zero-voltage-switching with Resonant Transition. A saturable core is used to achieve the self-excitation and the zero-voltage-switched Resonant Transition. The voltage waveform across the switch is trapezoidal with sinusoidal Transitions, and the current waveform flowing through the switch is quasisquare. The switching losses, the conduction losses and the stresses of the switch are significantly reduced in the proposed power converter. The output voltage is determined by the ON duty ratio of the switch as in a PWM converter. Two methods to modulate the ON duty ratio are proposed. Both methods results in variable-frequency operation. Experiments on two 5 V, 20 A DC-DC power converters show good performance. >
-
a novel self excited pwm forward converter with zvs Resonant Transition using two minor loop operated saturable cores
Power Electronics Specialists Conference, 1992Co-Authors: K. HaradaAbstract:A self-excited forward power converter is proposed. The turn-on and turn-off Transitions of the switch are zero voltage switched Resonant Transitions. Two saturable cores operated in minor B-H loop are used to achieve such Transitions. The waveform of the voltage across the switch is trapezoidal, and the current flowing in the switch is a quasi-square-wave. The switching losses are considerably reduced, and the stresses in the switch are significantly suppressed. The converter has load characteristics similar to those of a square-wave pulse-width-modulated (PWM) forward converter. The on duty ratio is modulated by a small current applied to the winding of one core. Experiments on a 350 kHz, 100 W DC-DC power converter show good performance. >
-
Novel self-excited PWM converters with zero-voltage-switched Resonant Transition using a saturable core
[Proceedings] APEC '92 Seventh Annual Applied Power Electronics Conference and Exposition, 1Co-Authors: K. HaradaAbstract:A new family of self-excited pulse-width-modulated (PWM) converters with zero-voltage-switched (ZVS) Resonant Transition is proposed. A saturable core is used in the transformer to realize the ZVS Resonant Transition during turn-on and turn-off Transition. The waveforms of the voltage across and current the switch the flowing in the switch are quasi-square-wave The converters have the advantages of both PWM and Resonant mode converters. >
Johann W. Kolar - One of the best experts on this subject based on the ideXlab platform.
-
optimal design of a 5kw dm 3 98 3 efficient tcm Resonant Transition single phase pfc rectifier
The International Power Electronics Conference - ECCE ASIA, 2010Co-Authors: Jurgen Biela, D. Hassler, J. Minibock, Johann W. KolarAbstract:In many applications single-phase PFC rectifiers should meet the demand for a high efficiency and a high power density at the same time. Depending on the weighting of these two design criteria, different topologies could be advantageous. As has been shown, with bridgeless PFC rectifiers an ultra high efficiency of 99.3% or a high power density of 5.6kW/dm3 could be realised. However, due to the hard switching operation it is not possible to achieve an exceptional efficiency and power density at the same time. Furthermore, SiC Schottky diodes are required for highly compact or highly efficient systems. Therefore, a triangular current mode (TCM), Resonant-Transition single phase PFC rectifier concept is presented in this paper, which overcomes both limitations. Besides a design procedure for optimising the chip area, also a simple and robust control concept, where a novel zero crossing detection concept is included, is explained and a prototype system as well as measurement results are presented for validating the concept and the design procedure.
-
interleaved triangular current mode tcm Resonant Transition single phase pfc rectifier with high efficiency and high power density
The International Power Electronics Conference - ECCE ASIA, 2010Co-Authors: C Marxgut, J Biela, Johann W. KolarAbstract:This paper presents a new topology for a highly compact and highly efficient single-phase Power Factor Corrected (PFC) rectifier system. The new topology consists of several interleaved boost stages which operate in a mode called Triangular Current Mode (TCM) in order to simultaneously achieve a high power density as well as a high efficiency. Applying TCM, ZVS is achieved over the full mains period by proper control of the power MOSFETs. The high TCM inductor current ripple is not transferred to the mains as the superposition of all boost cell input currents results in a smooth mains current waveform. Furthermore, one bridge leg operates synchronously to the mains frequency and connects the mains directly to an output rail. This results in very low common mode noise and only a small common mode filter has to be considered. The excellent behavior of this topology also applies to inverter operation.
-
Optimal design of a 5kW/dm 3 / 98.3% efficient TCM Resonant Transition single-phase PFC rectifier
The 2010 International Power Electronics Conference - ECCE ASIA -, 2010Co-Authors: Jurgen Biela, D. Hassler, J. Minibock, Johann W. KolarAbstract:In many applications single-phase PFC rectifiers should meet the demand for a high efficiency and a high power density at the same time. Depending on the weighting of these two design criteria, different topologies could be advantageous. As has been shown, with bridgeless PFC rectifiers an ultra high efficiency of 99.3% or a high power density of 5.6kW/dm3 could be realised. However, due to the hard switching operation it is not possible to achieve an exceptional efficiency and power density at the same time. Furthermore, SiC Schottky diodes are required for highly compact or highly efficient systems. Therefore, a triangular current mode (TCM), Resonant-Transition single phase PFC rectifier concept is presented in this paper, which overcomes both limitations. Besides a design procedure for optimising the chip area, also a simple and robust control concept, where a novel zero crossing detection concept is included, is explained and a prototype system as well as measurement results are presented for validating the concept and the design procedure.
-
Full-order averaging modelling of zero-voltage-switching phase-shift bidirectional DC-DC converters
IET Power Electronics, 2010Co-Authors: Chuanhong Zhao, S.d. Round, Johann W. KolarAbstract:Full-order small-signal modelling and dynamic analysis of zero-voltage-switching (ZVS) phase-shift bidirectional DC-DC converters is studied. A general modelling method is proposed to develop the discrete-time average model. This full-order model takes into account the leakage inductance current and the Resonant Transition intervals in order to realise ZVS. Both the leakage inductance current and the Resonant Transition intervals are the key to accurately predict the dynamic behaviour of the converter. A control-to-output-voltage transfer function is derived for the dual active bridge DC-DC converter, which is taken as an example to illustrate the modelling procedure. Experimental results confirm that the new model correctly predicts the small-signal frequency response up to one-third of the switching frequency and is more accurate than the previously presented models.
Peter Wolfs - One of the best experts on this subject based on the ideXlab platform.
-
A comparison study between series Resonant and zero-voltage-Resonant-Transition DC-DC converters
2015 Australasian Universities Power Engineering Conference (AUPEC), 2015Co-Authors: Umme Mumtahina, Peter WolfsAbstract:Modular power conditioning systems, where each PV module has its own power converter, have been proven to yield higher output power due to their superior maximum power point tracking capabilities. In PV strings the typical operating voltages pose reasonable electrical safety problems that can be overcome in conventional modules. For certain cell constructions, such as thin film arrays deposited onto roofing sheets, it is not possible to obtain sufficient galvanic isolation. Some cells, such as the back contact cells, suffer from surface charge accumulation or polarisation effects that can be solved by isolation. This paper presents a comparative loss analysis between zero-voltage-Resonant-Transition half bridge converter and series Resonant converters that rare intend to be used as module isolation converters. Detailed analysis of the operation of these two converters is discussed. Two low voltage hardware prototypes of 300W have been made whose efficiency is of 90% for series Resonant converter and 88% for zero voltage Resonant Transition converter.
-
The Power Loss Optimization of a Current Fed ZVS Two-Inductor Boost Converter With a Resonant Transition Gate Drive
IEEE Transactions on Power Electronics, 2006Co-Authors: Peter WolfsAbstract:This paper develops a power loss optimization method in a current fed zero-voltage switching (ZVS) two-inductor boost converter, which is suitable for the module integrated converter applications in grid interactive photovoltaic systems. The paper conducts the numerical analysis of the variable power loss components and establishes a set of the circuit parameters for an optimized operating point with a minimized average power loss. The ZVS two-inductor boost cell is fed from a sinusoidally modulated two-phase synchronous buck converter with an interphase transformer and produces a rectified sinusoidal voltage, which can be applied to an unfolding stage to generate the grid compatible voltage. The boost cell is also equipped with a Resonant Transition gate drive circuit to reduce the power loss in the drive circuit under high frequency operations. The experimental results for a prototype 1-MHz 100-W ZVS two-inductor boost converter are presented at the end of the paper
Pardo B - One of the best experts on this subject based on the ideXlab platform.
-
Parametric and Resonant Transition radiation in periodic stratified structures.
Physical Review E, 2002Co-Authors: Pardo BAbstract:We consider the problem of electromagnetic emission when an electrically charged particle crosses a periodically stratified structure following an arbitrary linear trajectory. A theory generalizing a recently developed method [Phys. Rev. E 63, 016613 (2001)] is presented in the framework of the classical theory of electromagnetism in continuous media. It allows one to account for both the so-called parametric radiation and the Resonant Transition radiation. We implement our model to interpret the experiments performed by Kaplin et al. [Appl. Phys. Lett. 76, 3647 (2000)] in the x-ray domain with a stack of 300 W/B 4 C hilayers irradiated by 500 MeV electrons.
-
Classical theory of Resonant Transition radiation in multilayer structures.
Physical Review E, 2000Co-Authors: Pardo BAbstract:A rigorous classical electromagnetic theory of the Transition radiation in finite and infinite multilayer structures is presented. It makes the standard results of thin-film optics, such as the matrix formalism, accountable; it allows thus an exact treatment of the propagation of the waves induced by the electron. This method is applied to the particular case of the periodic structures to treat the Resonant Transition radiation (RTR). It is noted that the present theory gives, in the hard x-ray domain, results previously published. The reason for this approach is to make the numerical calculations rigorous and easy. The numerical results of our theory are compared to experimental RTR data obtained recently by Yamada et al. [Phys. Rev. A 59, 3673 (1999)] with a nickel-carbon multilayer structure.
F. J. Hartmann - One of the best experts on this subject based on the ideXlab platform.
-
Observation of double-Resonant laser-induced Transitions in the v=n{minus}l{minus}1=2 metastable cascade of antiprotonic {sup 4}He atoms
Physical Review A, 1997Co-Authors: R. S. Hayano, F. E. Maas, T. Ishikawa, H. A. Torii, N. Morita, Hiroyuki Tamura, M. Hori, Mitsutaka Kumakura, Isao Sugai, F. J. HartmannAbstract:Another laser-induced Resonant Transition in the v=n{minus}l{minus}1=2 metastable cascade of antiprotonic {sup 4}He atoms has been found by using a double-resonance technique. This was done by setting the first laser to the already known 470.724-nm resonance [(n,l)=(37,34){r_arrow}(36,33)], while the (38,35){r_arrow}(37,34) Transition was searched for with the second laser. The Resonant Transition was found at a wavelength of 529.622{plus_minus}0.003 nm, showing excellent agreement with a recent prediction of Korobov. {copyright} {ital 1997} {ital The American Physical Society}
-
Laser-induced Resonant Transition at 470.724 nm in the v=n-l-1=2 cascade of metastable antiprotonic helium atoms
Physical review. A Atomic molecular and optical physics, 1995Co-Authors: F. E. Maas, R. S. Hayano, T. Ishikawa, Hirokazu Tamura, H. A. Torii, N. Morita, Toshimitsu Yamazaki, I. Sugai, K. Nakayoshi, F. J. HartmannAbstract:A laser-induced Resonant Transition in metastable antiprotonic helium atoms has been found at a wavelength of 470.724{plus_minus}0.002 nm and assigned to the Transition ({ital n},{ital l})=(37,34){r_arrow}(36,33). From the time evolution of the laser resonance intensity, the decay rate of the (37,34) state was determined to be 1.17{plus_minus}0.09 {mu}s{sup {minus}1}, about 60% larger than the theoretical radiative decay rate. The sum of the initial populations in the {ital v}={ital n}{minus}{ital l}{minus}1=2 decay chain was 23{plus_minus}4% of the total number of metastable atoms formed.