A new primary-side-assisted zero-voltage and zerocurrent switching full bridge dc–dc converter with transformer isolation is proposed. The proposed dc–dc converter uses only one auxiliary transformer and two diodes to obtain ZCS for the leading leg. It has a simple and robust structure, and load current control capability even in short circuit conditions. Possibility of magnetic saturation due ...

This paper deals with diagnostic methods of the internal faults in power transformers. The diagnostic process uses some of the current diagnosis methods (e.g. oil test, dissolved gases analysis (DGA), partial discharge (PD), etc.) to determine the condition of the transformer. In this process, the most frequent diagnostic methods were listed and applied practically to be compared. A conventiona...

Variable frequency transformer (VFT), introduced recently is a flexible asynchronous ac link which is used in power transferal process between asynchronous power system grids. VFT was first installed at Langlois substation, which interconnects the Hydro-Québec (Canada) and New York (USA) systems. The torque of the rotary transformer is externally altered in order to control the direction and ma...

Generation, transmission and distribution of electric energy are to be characterized by a very high degree of reliability. Reliability level is directly related to the quality of the equipment used and the periodic maintenance carried out on the system. In our country, the distribution system is the most neglected part, which is being given some importance only in the recent years. Distribution...

A bi-directional multi-port converter can accommodate various energy storages and sources. Therefore, a multiport converter will be a good candidate for application as a future universal converter for (hybrid) electrical vehicles or local distribution systems. The main design challenge of the multiport converter analyzed in this paper is the design of its three-phase symmetrical transformer. In...

High power and high voltage gain DC-DC converters are key to high-voltage DC (HVDC) power transmission for offshore wind power. This paper presents an isolated ultra-high step-up DC-DC converter in matrix transformer configuration. A flyback-forward converter is adopted as the power cell and the secondary side matrix connection is introduced to increase the power level and to improve fault tole...

The uncontrolled three-phase bridge rectifier has the least line current distortion among six-pulse rectifiers; however, its total harmonic distortion (THD) of 31.08% is unacceptable as per the contemporary power quality standards. This paper seeks to address the issue by elimination of triplen harmonics in the line currents by providing a deltawye transformer at the ac interface i.e. between t...

The paper describes a novel neural model to estimate electrical loss in transformer according to the energy consumption (load curve). The network acts as identifier of structural features on electrical loss process, so that output parameters can be estimated and generalized from an input parameter set. The model was trained and assessed through experimental data taking into account core loss, c...