A Novel Driving Scheme for Three-Phase Bearingless Induction Machine with Split Winding

In order to reduce the costs of implementing the radial position control system of a three-phase bearingless machine with split winding, this article proposes a driving method that uses only two phases of the system instead of the three-phase traditional one. It reduces from six to four the number of inverter legs, drivers, sensors, and current controllers necessary to drive and control the system. To justify the proposal, this new power and control configuration was applied to a 250 W machine controlled by a digital signal processor (DSP). The results obtained demonstrated that it is possible to carry out the radial position control through two phases, without loss of performance in relation to the conventional three-phase drive and control system.

Analysis of Turn-to-Turn Fault on Split-Winding Transformer Using Coupled Field-Circuit Approach

The turn-to-turn faults (TTF) are also inevitable in split-winding transformers. The distorted leakage field generated by the TTF current results in large axial forces and end thrusts in the fault windings as well as affecting other branch windings normal operation, so it is of significance to study TTF of split-winding transformers. In this paper, the characteristics analysis of the split-winding transformer under the TTFs of the low voltage winding at different positions are presented. A 3600 KVA four split-windings transformer is taken as an example. Then, a simplified three-dimensional simplified model is established, taking into account the forces of the per-turn coil. The nonlinear-transient field-circuit coupled finite element method is used for the model. The leakage field distribution under the TTFs of the low voltage winding at different positions is studied. The resultant force of the short-circuit winding and the force of the per-turn coil are obtained. Subsequently, the force and current relationship between the branch windings are analyzed. The results show that the TTF at the specific location has a great influence on the axial windings on the same core, and the distorted leakage magnetic field will cause excessive axial force and end thrust of the normal and short-circuit windings. These results can provide a basis for the short-circuit design of split-winding transformer.

Current modeling in a bus packet of a high-current system

A graphoanalytic method for determining the highcurrent system resistances and a mathematical model of a single-phase furnace transformer with a split secondary winding are developed for modeling currents in a transformer and a high-current system bus package in case of short circuit and opening of flexible connections. Experiments have proved the adequacy of the proposed method. The simulation error does not exceed 10 %. Keywords: single-phase transformer, split winding, short circuit, high-current system, opening, resistance, mathematical model, modeling. [email protected]

The design and practical implementation of a six-phase induction motor

This thesis presents a re-designed conventional three phase 5-hp squirrel cage, 4-pole, 48 slots induction motor to a six-phase induction motor (SPIM). It also presents the in-depth of a single layer winding of a three-phase motor that was re-design to the six-phase split winding layout which was practically explained to the understanding of both the engineers and the technicians who normally find it difficult with windings of electrical machines. The optimized re-designed SPIM is presented in the MATLAB/Simulink environment to perform a comparative assessment of the different phase loss scenarios of the six-phase configuration with respect to the six-phase healthy case and its conventional three-phase induction motor. The result shows a comparative benefit of the six-phase induction motor over the three-phase induction motor; in such that in the near future because of its effective way to provide a higher reliability and sustainability under the loss of phase/phases condition it will be practically applied in the power driven devices/machines like in the area of Electric Vehicles, etc.