Optimizing three-phase planar transformer construction

A three-phase transformer with flat conductor layers is proposed in this article. This arrangement is used for high current density transformers. Cost effectiveness in planar magnetic are related with the optimization in the number of layers in each winding. This fact takes more relevance for the medium and high power three-phase transformers where the number of parallels to achieve the required DCR is increased. The proposed method allows the use of off-the-shell core shapes that are used for single phase transformers. Cost impact is significant and design implications become more flexible. The proposed solution has been validated and compared using the conventional and the proposed methodologies to design a high power (20 kW) transformer.

Analysis and optimized design of a distributed multi-stage EMC filter for an interleaved three-phase PWM-rectifier system for aircraft applications

Different possible input filter configurations for a modular three-phase PWM rectifier system consisting of three interleaved converter cells are studied. The system is designed for an aircraft application where MIL-STD-461E conducted EMI standards have to be met and system weight is a critical design issue. The importance of a LISN model on the simulated noise levels and the effect of interleaving and power unbalance between the different converter modules is discussed. The effect of the number of filter stages and the degree of distribution of the filter stages among the individual converter modules on the weight and losses of the input filter is studied and optimal filter structures are proposed.

An alternative for reducing the layers in the construction of three-phase planar transformers

A modified winding layout for three-phase transformers with PCB windings is proposed in this paper. This modified layout can be used in high current transformers with many PCB layers to simplify the fabrication process. One of the key factors that might increase the cost and complexity in the construction of planar transformers is the number of layers of each PCB winding. This issue becomes even more important in medium-high power three-phase transformers, where the number of PCB layers is higher. In addition to that, the proposed method allows the use of commercial core shapes that are commonly used to design single-phase transformers. This fact makes possible the reduction of cost and flexibility of the design solutions. The proposed solution has been validated and compared using the conventional and the proposed methodologies to design a high power (20 kW) transformer.

Adaptive Control for ZVS Three Phase Full Active Bridge Converter with ARCN

This paper presents an adaptive control for the auxiliary circuit, called ARCN (Auxiliary Resonant Commutating Network), used to achieve ZVS in full active bridge converters under a wide load range. Depending on the load conditions, the proposed control adapts the timing of the ARCN to minimize the losses. The principle of operation and implementation considerations are presented for a three phase full active bridge converter, proposing different methods to implement the control according to the specifications. The experimental results shown verify the proposed methodology.

Interleaved multi-cell isolated three-phase PWM rectifier system for aircraft applications

Recently there has been an important increase in electric equipment, as well as, electric power demand in aircrafts applications. This prompts to the necessity of efficient, reliable, and low-weight converters, especially rectifiers from 115VAC to 270VDC because these voltages are used in power distribution. In order to obtain a high efficiency, in aircraft application where the derating in semiconductors is high, normally several semiconductors are used in parallel to decrease the conduction losses. However, this is in conflict with high reliability. To match both goals of high efficiency and reliability, this work proposes an interleaved multi-cell rectifier system, employing several converter cells in parallel instead of parallel-connected semiconductors. In this work a 10kW multi-cell isolated rectifier system has been designed where each cell is composed of a buck type rectifier and a full bridge DC-DC converter. The implemented system exhibits 91% of efficiency, high power density (10kW/10kg), low THD (2.5%), and n−1 fault tolerance which complies, with military aircraft standards.

A report on the three-dee, three-phase 20-inch cyclotron /

Unclassified Physics Distribution.

The Boston Handel and Haydn Society collection of church music : being a selection of the most approved psalm and hymn tunes, anthems, sentences, chants, &c. : together with many beautiful extracts from the works of Haydn, Mozart, Beethoven, and other eminent composers, harmonized for three and four voices, with a figured base for the organ and piano forte /

Mode of access: Internet.

School architecture; one-, two-, three- and four-room school buildings.

Mode of access: Internet.

The song-sheaf : a collection of vocal music arranged in one, two, three, and four parts: containing also a complete elementary course, for schools, academies, and the social circle /

Most of the songs have pianoforte accompaniment.

Three phase system for statewide evaluation of occupational education programs : team leader handbook.

Cover title.

Musica sacra : or Springfield and Utica collections united: consisting of psalm and hymn tunes, anthems and chants; arranged for two, three or four voices, with a figured bass for the organ or piano forte.

Combines the "Springfield collection", edited by Warriner (Springfield, 1813) and "Musica sacra", published for the Oneida musical society (Utica, 1816)

The wagonauts abroad : two tours in the wild mountains of Tennessee and North Carolina, made by three kegs, four wagonauts and a canteen, in two parts /

Mode of access: Internet.

Lessons for children from three to four years old.

Mode of access: Internet.

Part songs, for three and four female voices /

Includes index.