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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01 Jan 1996
TL;DR: The size of a power transformer of commercial frequency is miniaturized by introducing a modulator and various functions, such as constant voltage, constant power and power factor correction are realized by a phase control system.
Abstract: A new concept of an intelligent power transformer is presented in this paper, where the size of a power transformer of commercial frequency is miniaturized by introducing a modulator. In this circuit, various functions, such as constant voltage, constant power and power factor correction are realized by a phase control system.
87 citations
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21 May 2008TL;DR: In this article, a single-stage isolated buck-type converter is coupled with an output rectifier and a semiconductor tap switch, which couples a larger portion of the secondary winding to an output bulk capacitor during the portions of the input sinewave half-cycle.
Abstract: A regulated power factor corrected power supply apparatus is provided. The apparatus includes an input rectifier circuit for receiving an input AC voltage and outputting a full-wave rectified DC voltage. A single-stage isolated buck-type converter is coupled with the input circuit. The converter circuit comprises an isolated buck-type converter circuit including an isolation transformer. An output rectifier and semiconductor tap switch are coupled to a secondary winding of the isolation transformer. The tap switch couples a larger portion of the secondary winding to an output bulk capacitor during the portions of the input sinewave half-cycle, which are low in amplitude. The tap switch enables the single-stage isolation buck-type converter to operate over a much larger portion of the input sinewave, but also allows the converter to operate at high-efficiency over the majority of the input sinewave.
86 citations
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29 Jul 1992
TL;DR: In this paper, a power line conditioner is proposed to protect sensitive electronics in modern electronic equipment from disruption or destruction caused by transients which can cause both induction and injection currents into the grounding system of the electronic equipment.
Abstract: A power conditioning device protects sensitive electronics in modern electronic equipment from disruption or destruction caused by transients which can cause both induction and injection currents into the grounding system of the electronic equipment. This device nominally comprises an isolation transformer and a ground impedance between the earth ground connection from a distribution panel and the safety ground connection to the powered equipment. In addition, this device may also comprise a voltage clamping device such as an MOV and a capacitive filter to provide a complete power line conditioner. This device may be used in systems with guarded or driven grounds, or in a system with a high voltage reference to safety ground. In addition, ground conditioning can be added to a Ground Fault Circuit Interrupter (GFCI) to attenuate ground surge currents. The ground impedance may take many forms, including inductors, resistors, diodes, gas tubes, transformers, capacitors, or combinations of these or other components. The ground conditioning device may be used on power systems of different voltages and frequencies, including three phase power systems.
86 citations
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TL;DR: In this article, an H-bridge-based three-phase three-stage modular power electronic transformer (PET) is proposed to deal with the dc-link capacitor voltage unbalancing issue and the parallel-connected module current imbalance sharing issue.
Abstract: Compared with conventional power transformer, the power electronic transformer (PET) or solid-state transformer has many attractive additional features. This paper focuses on an H-bridge-based three-phase three-stage modular PET, which consists of an input stage with series-connected H-bridge converters, an isolation stage with several independent dual-active-bridge converters, and an output stage with parallel-connected H-bridge converters. This PET suffers dc-link capacitor voltage unbalancing issue, and the parallel-connected module current unbalancing sharing issue. In this paper, a system control structure is proposed for the PET to deal with these issues. Different input-stage individual module dc-link voltage balancing control methods are analyzed and compared. It is found that the one implemented by directly trimming module output voltage amplitude is most suitable for PET. Moreover, a downscaled laboratory prototype is designed, built, and tested to verify the control strategy.
86 citations
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TL;DR: A system scale approach that uses capacitive coupling for power and signal isolation is presented and the development of an instrumentation system prototype that applies microwaves for power exchange and bidirectional data transfer across the isolation barrier is described.
Abstract: Requirements for patient safety and a high interference rejection ratio in medical equipment create a demand for effective isolation devices. A system scale approach that uses capacitive coupling for power and signal isolation is presented. In addition, we describe the development of an instrumentation system prototype that applies microwaves for power exchange and bidirectional data transfer across the isolation barrier. The system consists of an isolated transducer unit, a central unit, and a single coaxial cable between the units. The isolation capacitance is as low as 1.6 pF, inclusive of the digital data transfer and power exchange up to 600 mW of isolated direct current (dc) power. The system is suitable for line-powered biopotential measurements and it is shown that reducing the isolation capacitance from 180 to 1.6 pF improves the power line rejection by 30 dB in a typical electrocardiogram (ECG) measurement setup.
86 citations