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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.


Papers
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Proceedings ArticleDOI
20 Mar 2016
TL;DR: In this paper, a 15 kV SiC MOSFET gate drive circuit is presented, which features high commonmode (CM) noise immunity, small size, light weight, and robust yet flexible protection functions.
Abstract: This paper presents a 15 kV SiC MOSFET gate drive circuit, which features high common-mode (CM) noise immunity, small size, light weight, and robust yet flexible protection functions. To enhance the gate-drive power reliability, a power over fiber (PoF) based isolated power supply is designed to replace the traditional design based on isolation transformer. It delivers the gate-drive power by laser light via optical fiber over a long distance (>1 m), so a high isolation voltage (>20 kV) is achieved, and the circuit size and weight are reduced. More importantly, it eliminates the parasitic CM capacitance coupling the power stage and control stage, and thus eradicates the control signal distortion caused by high dv/dt in switching transients of the high-voltage SiC devices. In addition, the gate drive circuit design integrates comprehensive protection functions, including the over-current protection, under/over-voltage lockout, gate-clamping, soft turn-off, and fault report. The over-current protection responds within 400 ns. Experimental results from a 15 kV double pulse tester are presented to validate the design.

34 citations

Proceedings ArticleDOI
Ji Shengchang1, Shan Ping, Li Yanming, Xu Dake, Cao Junling 
19 Nov 2001
TL;DR: In this paper, the principle of monitoring the power transformer core and winding conditions via measuring the tank vibration is described, and a set of measuring system was set up, also some techniques of anti-interference were adopted.
Abstract: Electric utilities are concerned about the availability and reliability of power transformers. The ability to diagnose the integrity of the transformer windings and core through the nonintrusive vibration tests would be useful to accurately assess transformer condition. In this article, the principle of monitoring the power transformer core and winding' conditions via measuring the tank vibration is described. By reasonably choosing the vibration sensor and the charge-amplifier, a set of measuring system was set up, also some techniques of anti-interference were adopted. Using this measuring system, the tank vibration signals of transformer were picked up in the lab. From the frequency spectra of the vibration signals, it can indicate that it is feasible to monitor on-line the core and winding condition of the power transformer by measuring the tank vibration.

34 citations

Patent
18 Mar 1993
TL;DR: In this paper, a push-pull inverter is supplied from an inductively current-limited DC voltage source by way of a center-tap on a transformer having significant inductance.
Abstract: A push-pull inverter is supplied from an inductively current-limited DC voltage source by way of a center-tap on a transformer having significant inductance. This transformer inductance is parallel-coupled with a capacitance means. The inverter is made to self-oscillate through positive feedback provided by way of a saturable current transformer. The inverter frequency is determined by the saturation time of this current transformer, which saturation time is designed to be somewhat longer than the half-cycle period of the natural resonance frequency of the transformer inductance combined with the capacitance means. By controlling the length of this saturation time, the magnitude of the current provided to the fluorescent lamp is controlled, thereby permitting control of the light output in response to changes in the magnitude of the power line voltage.

34 citations

Patent
02 Sep 2010
TL;DR: In this paper, an AC/DC converter system comprises an input circuit for connection to a three phase AC source, an output circuit is connected between the AC and DC converter and a DC load.
Abstract: An AC/DC converter system comprises an input circuit for connection to a three phase AC source. An isolation transformer comprises a set of primary windings and first and second sets of secondary windings magnetically coupled to the set of primary windings. The first and second sets of secondary windings are phase shifted by select amounts from the set of primary windings. The set of primary windings is connected to the input circuit. An AC/DC converter comprises first, second and third three phase rectifiers, the first three phase rectifier being powered by the first set of secondary windings, the second three phase rectifier being powered by the second set of secondary windings, and the third three phase rectifier being powered by the input circuit. An impedance matching inductor is electrically connected between the input circuit and the third three phase rectifier. An output circuit is connected between the AC/DC converter and a DC load.

34 citations

Patent
28 Oct 1988
TL;DR: In this paper, a new principle for high efficiency power conversion at high frequencies is described, which provides zero voltage switching by using the magnetising current of a transformer or parallel inductance to charge the switch adjunct capacitance and other capacitance during the dead time.
Abstract: A new principle for high efficiency power conversion at high frequencies is described. The principle provides zero voltage switching by using the magnetising current of a transformer or parallel inductance to charge the switch adjunct capacitance and other capacitance during the dead time. The transformer is prevented from being loaded during the dead time. An embodiment of the invention is described where loading of the transformer during the dead time is prevented by directing the output inertial current to a capacitor instead of through the rectifiers to the secondary of the transformer. This can also be achieved by using synchronised rectification that provides pulse width modulated regulation on the output and ensures that the transformer secondary is separated from the inertial current of the output during the dead time. Voltage and current stresses on the switching devices and rectifiers are minimised. The principle may be applied to inverters where the load is resistive.

34 citations


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