Topic
Isolation transformer
About: Isolation transformer is a research topic. Over the lifetime, 8145 publications have been published within this topic receiving 72396 citations.
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TL;DR: An operating principle on how the contactless transformer with commercialized core contributes to the low efficiency is discussed and a new frequency-dependent R- L ladder circuit model is introduced for the design-oriented analysis of wide-air-gap contactless power converters including the frequency- dependent losses of the transformer.
Abstract: A wireless power converter topology with a small size and a high conversion efficiency has an increasing demand on small-power applications. Some design techniques to transmit power by customized cores have been already developed. However, when transferring energy by wide-gap transformers employing small-sized commercialized cores, the power losses on the winding greatly increase as the frequency increases. Then, the efficiency of the contactless power system decreases significantly due to the conduction loss and reactive components in the resonant circuit. Even though series–parallel resonant converters are largely employed, which can provide an infinite shunt impedance regardless of the coupling coefficient, when a commercialized core is employed for loosely coupled contactless power transfer applications, the large leakage inductance of the transformer significantly influences the additional power dissipation on the transformer windings. In this paper, an operating principle on how the contactless transformer with commercialized core contributes to the low efficiency is discussed. Also, a new frequency-dependent $R$ – $L$ ladder circuit model is introduced for the design-oriented analysis of wide-air-gap contactless power converters including the frequency-dependent losses of the transformer. A new design procedure with the proposed model is suitable for the contactless transformers employing commercialized cores. The proposed design approach is validated by 98.8-W hardware experiments. Finally, the simulation waveforms and the hardware results are compared to verify the accuracy of the frequency-dependent transformer model.
20 citations
TL;DR: In this paper, a photomultiplier high voltage power supply with a non-magnetic piezoelectric ceramic core is described, which leaks no flux and can operate in the presence of a strong magnetic field.
Abstract: We describe a photomultiplier high voltage power supply in which the transformer, conventionally implemented with a magnetic core, is built with a non-magnetic piezoelectric ceramic. As this "ceramic transformer" leaks no flux and can suitably operate in the presence of a strong magnetic field, it is attractive for use in high energy physics experiments requiring high voltage generation under such fields. In addition, the ceramic transformer suffers low loss of power and demonstrates highly efficient energy conversion.
20 citations
Patent•
20 Dec 2001TL;DR: In this paper, a control circuit for controlling a power switch by means of a galvanic insulation transformer is described, the transformer being produced in the form of planar conductive windings on an insulating substrate whereon are integrated passive components constituting a high frequency excitation oscillating circuit for a primary winding of the transformer, the substrate being directly mounted on a wafer whereon is mounted a circuit chip integrating the power switch.
Abstract: The invention concerns a control circuit for controlling a power switch by means of a galvanic insulation transformer, the transformer being produced in the form of planar conductive windings on an insulating substrate (20) whereon are integrated passive components constituting a high frequency excitation oscillating circuit for a primary winding of the transformer, the transformer substrate being directly mounted on a wafer (24) whereon is mounted a circuit chip (40) integrating the power switch.
20 citations
Patent•
07 Mar 2001
TL;DR: In this paper, a three-level DC converter is composed of input voltage dividing capacitors, inverting bridge, isolating transfurmer, rectifier and filter, and features that a clamper is introduced at the intersection of primary winding of isolating transformer and resonant inductor.
Abstract: A three-level DC converter is composed of input voltage dividing capacitors, inverting bridge, isolating transfurmer, rectifier and filter, and features that a clamper is introduced at the intersection of primary winding of isolating transformer and resonant inductor. Two clamping diodes are respectively connected between two switch transistor of a pair in inverting bridge. Its advantages are zero-voltage switching of switch transistor, no voltage oscillation caused by backward restoration of rectifying transistor, low voltage stress of output rectifying transistor, and no backward restoring loss of output rectifying transistor.
20 citations
TL;DR: In this article, a bendable transformer for wearable electronics is presented, printed on a thin and bendable film, which is bendable to wrap around body limbs such as the forearm.
Abstract: This paper presents a study of a bendable transformer for wearable electronics. Printed on a thin and bendable film, this transformer is bendable to wrap around body limbs such as the forearm. A model using a partial equivalent circuit theory has been developed to analyze the characteristic of an inductor and a bendable transformer. The mutual inductance and self-inductance for the bendable transformer over a range of bent curvatures have been calculated based on the model and compared favorably with measurements. Simulation and experimental results of applying the bendable inductor and transformer in dc–dc converters as a 5-V 500-mA power supply are included to confirm the usefulness of the transformer and the validity of the model.
20 citations