Isolation transformer

About: Isolation transformer is a research topic. Over the lifetime, 8145 publications have been published within this topic receiving 72396 citations.

A matrix converter-based topology for high power electric vehicle battery charging and V2G application

Abstract: In this paper, a new three-phase converter topology based on a 3x1 matrix converter (MC) is proposed for Plug-in Hybrid or Battery (PHEV/BEV) electric transit buses. In the proposed approach, the MC directly converts the low frequency (50/60 Hz, three-phase) input to a high frequency (6 kHz, one-phase) AC output without a dc-link. The output of the matrix converter (MC) is then processed by a PWM rectifier via a high frequency (HF) isolation transformer to interface with the EV battery system. The MC-PWM rectifier system is made to operate like a dual active bridge (DAB), facilitating bi-directional power flow suitable for charging and Vehicle-to-Grid (V2G) application. The digital control of the system ensures that the input currents are of high quality under both charging and discharging operations. Due to the absence of dc-link electrolytic capacitors, power density of the proposed rectifier is expected to be higher. Analysis, design example and extended simulation results are presented for a three-phase 208 V LL , 50kW charger.

Isolated dynamic current converters

Abstract: Isolated Dynamic-Current (“Dyna-C”) converters are converters that convert incoming 3-phase AC or DC power to a mix of DC and AC power via an isolation link. In various embodiments, the isolation link is a high-frequency isolation transformer. Isolated Dyna-C converters may provide a high-frequency galvanic isolation and are able to convert three-phase AC power to three-phase AC power, or three-phase AC power to DC and vice versa. The topology is minimal and the costs are low. Isolated Dyna-C converters provide fast current responses and keep the losses low by using a simplified two-stage conversion and providing a magnetizing current that is dynamically controllable and tailored to the load. An isolated Dyna-C converter may synthesize currents at its input or output ports with an arbitrary phase that is relative to the grid or load voltages, thereby enabling a full independent control over the active and reactive power at its ports.

Electrically isolated signal path means for a physiological monitor

Abstract: A circuit for providing electrical isolation between a patient and physiological monitoring apparatus comprising an amplifier, having applied to the input thereof a physiological signal from the patient, and a first circuit branch including an isolation transformer connected between a modulator and a demodulator for connecting a d.c. voltage source of relatively low magnitude to the amplifier. Connected to the amplifier output is a second circuit branch comprising an isolation transformer connected between a modulator and a demodulator, and the output of the demodulator is coupled to the input of physiological monitoring apparatus. Each of the isolation transformers includes an extremely low capacitance between the primary and secondary windings thereof to present an extremely high reactance to low frequency, including line frequency, alternating current and each is capable of withstanding relatively high voltages without breakdown.

High-Frequency Power Transformers With Foil Windings: Maximum Interleaving and Optimal Design

Abstract: Foil conductors and primary and secondary interleaving are normally used to minimize winding losses in high-frequency (HF) transformers used for high-current power applications. However, winding interleaving complicates the transformer assembly, since taps are required to connect the winding sections, and also complicates the transformer design, since it introduces a new tradeoff between minimizing losses and reducing the construction difficulty. This paper presents a novel interleaving technique, named maximum interleaving , that makes it possible to minimize the winding losses as well as the construction difficulty. An analytical design methodology is also proposed in order to obtain free-cooled transformers with a high efficiency, low volume, and, therefore, a high power density. For the purpose of evaluating the advantages of the proposed maximum interleaving technique, the methodology is applied to design a transformer positioned in the 5 kW–50 kHz intermediate HF resonant stage of a commercial PV inverter. The proposed design achieves a transformer power density of 28 W/cm3 with an efficiency of 99.8%. Finally, a prototype of the maximum-interleaved transformer is assembled and validated satisfactorily through experimental tests.

Medical apparatus including on isolating transformer apparatus for isolating medical apparatus from non-medical apparatus to prevent electrical shocks to patients

Abstract: A medical apparatus comprises an electrical medical apparatus for use with an endoscope connectable thereto and adapted for at least one a diagnostic and medical treatment; at least one electrical non-medical apparatus including a line cord and a plug, which is used in association with the electrical medical apparatus; and an isolating transformer apparatus isolating a patient from electrical shocks from the electrical medical apparatus used together with the electrical non-medical apparatus. The isolating transformer apparatus is connectable by an authorized person to a commercial power supply and is connected to the line cord and plug of the electrical non-medical apparatus. The electrical medical apparatus is connectable to the commerical power supply. The isolating transformer apparatus includes a housing having a plurality of walls; a transformer contained in the housing, the transformer having a primary winding which is connectable to the commercial power supply, and a secondary winding which is electrically isolated from the primary winding; and a power supply socket mounted on a wall of the housing and being connected to the secondary winding, the socket receiving the plug of the electrical non-medical apparatus. The isolating transformer apparatus also has a retainer provided on an outside portion of the housing for preventing the plug of the electrical non-medical apparatus from being removed from the power supply socket, and a lock device for locking the retainer for preventing removal of the retainer without an engaging and disengaging tool.