performing fast and accurate methods for modeling the electrical machines has been the subject of several studies and many authors proposed different procedures to attain this aim. beside the accuracy, the speed of the method is of great concern. on the other hand, the capability of the method to be changed according to the need is another important issue. finite element method provides relativ...

The objective of this paper is to present a multilevel inverter topology for induction motor with open-end winding. Multi level inversion is achieved by feeding an open-end winding induction motor with a two-level inverter in cascade with three auxiliary circuits from one end and a single two-level inverter from the other end of the motor. The combined inverter and auxiliary system with open-en...

Single-phase induction motors have a wide range of domestic and industrial applications. These motors have a squirrel cage rotor and their stator usually has two windings: main and auxiliary. The use of auxiliary winding in the structure of single-phase induction motors creates two unbalance and asymmetric phases. This causes to increase the spatial harmonics of the field in the air gap, and al...

Power transformers with superconducting windings need a protection system to prevent damage to the low-loss superconducting winding by an abnormally high current. The generally accepted protection technique which uses auxiliary coils has been analysed using a network representation. The current distribution between main and auxiliary coil is expressed in terms of geometrical parameters. Experim...

The search for replacement of commutator and brushes in conventional DC motors by electronic commutator has resulted in a class of Permanent Magnet Brush Less (PMBL) motors. The operation of PMBL motor requires synchronization of coil currents with the instantaneous rotor position. The applied voltages of higher magnitudes must have same zero crossings as that of speed induced back EMF of the r...

An original electronic device for compensating ratio and phase-displacement errors, of measuring current transformers and clamp-on probes, is proposed. It is specially intended for low-frequency applications (power frequency and its harmonic components), where the magnetizing current is the main cause of measuring errors. This system reduces the magnetic flux in the transformer core, reducing i...

This paper presents a family of soft-switching DC–DC converters with a simple auxiliary circuit consisting of a coupled winding and a pair of auxiliary switch and diode. The auxiliary circuit is activated in a short interval and thus the circulating conduction losses are small. With the auxiliary circuit, zero-voltage-switching (ZVS) and zero-current-switching are achieved for the main and auxi...

Performing fast and accurate methods for modeling the electrical machines has been the subject of several studies and many authors proposed different procedures to attain this aim. Beside the accuracy, the speed of the method is of great concern. On the other hand, the capability of the method to be changed according to the need is another important issue. Finite Element method provides relativ...

–Harmonic pollution and low power factor in power systems caused by power converters have been of great concern. To overcome these problems several converter topologies using advanced semiconductor devices and control schemes have been proposed. This investigation is to identify a low cost, small size, efficient and reliable ac to dc converter to meet the input performance index of UPS. The per...

ABSTRACT : In the proposed system, the power factor is improved by using an auxiliary winding coupled to the transformer of a cascade dc/dc fly back converter. The auxiliary winding is placed between the input rectifier and the low-frequency filter capacitor to serve as a magnetic switch to drive an input inductor. Since the dc/dc converter is operated at high-switching frequency, the auxiliary...