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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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Proceedings ArticleDOI
01 Jul 2013
TL;DR: A relation associated with core losses and amplitude of high harmonic order are reviewed & analyzed and then a comparison is being carried out on the results obtained by different excitation current in transformer windings.
Abstract: Transformers are normally designed and built for use at rated frequency and sinusoidal load current. A non-linear load on a transformer leads to harmonic power losses which cause increased operational costs and additional heating in transformer parts. It leads to higher losses, early fatigue of insulation, premature failure and reduction of the useful life of the transformer. To prevent these problems, the rated capacity of transformer which supplies harmonic loads must be reduced. In this work a typical 50 KVA three phase distribution transformer with real practical parameters is taken under nonlinear loads generated due to domestic loads. The core losses is evaluated using the three dimensional model of the transformer developed in Ansoft Maxwell based on valid model of transformer under high harmonic conditions. And finally a relation associated with core losses and amplitude of high harmonic order are reviewed & analyzed and then a comparison is being carried out on the results obtained by different excitation current in transformer windings.

19 citations

Proceedings ArticleDOI
23 Aug 2004
TL;DR: In this article, the authors developed a good understanding of the laminated piezoelectric transformer designs and their related properties, such as bonding materials, electrode materials and constructive parameters, and found that stycast/spl reg/1264 is a promising bonding material to improve transformer characteristics in terms of mechanical quality factor, efficiency and output power.
Abstract: This research was aimed to develop a good understanding of the laminated piezoelectric transformer designs and their related properties, such as bonding materials, electrode materials and constructive parameters. We found that Stycast/spl reg/ 1264 is a promising bonding material to improve transformer characteristics in terms of mechanical quality factor, efficiency and output power. Size and shape of the piezoelectric element also affect the transformer's performance. It showed that the power capability of piezoelectric transformer can be increased when the disk-shape and bigger size of piezoelectric elements are used. From this study, the maximum output powers of approximately 7 and 36 W were obtained for 23.8 and 45.0 mm diameter piezoelectric transformers with the same total thickness, respectively. These laminated transformers exhibit approximately three times higher power density than a rectangular Rosen-type piezoelectric transformer with a similar volume.

19 citations

Patent
Zaohong Yang1, Paul Garrity1
07 May 2010
TL;DR: An energy recovery snubber circuit for switching power converters is described in this paper, where the clamped voltages are captured by an energy capture module, such as a capacitor.
Abstract: An energy recovery snubber circuit for use in switching power converters. The power converters may include a switch network coupled to a primary winding of an isolation transformer, and rectification circuitry coupled to a secondary winding of the isolation transformer. The energy recovery snubber circuit may include clamping circuitry that is operative to clamp voltage spikes and/or ringing at the rectification circuitry. The clamped voltages may be captured by an energy capture module, such as a capacitor. Further, the energy recovery snubber circuitry may include control circuitry operative to return the energy captured by the energy capture module to the input of the power converter. To maintain electrical isolation between a primary side and a secondary side of the isolation transformer, a second isolation transformer may be provided to return the captured energy back to the input of the power converter.

19 citations

Journal ArticleDOI
TL;DR: A review of known magnetic-coupled current-sensing techniques is presented and a novel technique is introduced, based on a configuration discussed in a previous paper, to obtain a high bandwidth and very high common-mode rejection current transformer without the need for a Hall effect probe.
Abstract: A review of known magnetic-coupled current-sensing techniques is presented, Subsequently, a novel technique is introduced, based on a configuration discussed in a previous paper. The previous technique made use of a galvanomagnetic device (Hall effect sensor) to sense the magnetization of a current transformer core, so that the sum of the Hall voltage and the voltage across the secondary shunt resistor would yield a faithful copy of the input current. The technique described in this paper makes use of the same principle to obtain a high bandwidth (from DC to 1 MHz) and very high common-mode rejection current transformer, without the need for a Hall effect probe. This is achieved by subtracting the high-frequency components, detected across the secondary shunt resistor, from the voltage across a primary shunt resistor connected in series with the primary of the current transformer. The resulting signal is an accurate image of the transformer magnetizing current, which is then transferred to the secondary side by means of a low-bandwidth isolation amplifier. The high-frequency components are subsequently added, to the amplified and filtered low-frequency components, by means of a third transformer winding, the number of turns of which is chosen to be equal to the gain of the low-frequency amplifier.

19 citations

Patent
27 Sep 2004
TL;DR: In this paper, a flyback power converter with a simplified topology is used to provide power factor correction while supplying constant output power to drive an inverter supplying low frequency modulated power to the HID lamp.
Abstract: An HID ballast includes a flyback power converter with a simplified topology that permits power factor correction while supplying constant output power to drive an inverter supplying low frequency modulated power to the HID lamp. A switch is coupled in series with a transformer in the power converter to control current through the transformer to provide constant output power. The off time of the switch contributes to controlling the power factor of the ballast circuit. The transformer is operated in critical conduction mode, with an indication of zero current in the transformer used to determine the control for the switch. An output of the flyback power converter provides a feedback signal to obtain constant power output based on switching intervals applied to the switch coupled to the transformer. This simplified topology reduces part counts while providing a robust control that can be flexibly applied to a number of HID lamps.

19 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202313
202251
202144
2020151
2019211
2018266