Antonio Carlos Ferreira

Operating points of a doubly fed cascaded induction machine

This paper will describe the operating possibilities of a Doubly Fed Cascaded Induction Machine. Some of the advantages of this system, for example, the controllable synchronous speed operation over a limited speed range and the reduced power converter rating, will be highlighted and explored with computer simulations.

Finite element analysis of the forces developed on linear induction motors

Superconducting magnetic levitation (SML) vehicles use a levitation technology based on the diamagnetic property of Y-Ba-Cu-O blocks and the magnetic field of Nd-Fe-B magnets. Brazilian SML project, MagLev-Cobra uses for the propulsion a short primary linear induction motor (LIM) with a squirrel cage secondary type. SupraTrans 2, the Germany MagLev vehicle, uses a short primary motor with secondary with copper plate and back-iron. Both motors assembly contribute to increase the levitation force. Brazilian tests with one levitating module on a 12 m track have shown a variation of the levitation height with the motor loading. In this paper, 2D - 3D finite element analysis will be used to study lateral, levitation and traction forces. Simulation and experimental results will be compared.

Force and current characteristics of a linear induction motor used for the traction of a MagLev vehicle

This paper describes the constructive form of a linear induction motor applied to the traction of MagLev-Cobra levitation vehicle and the required control to a secure and economic driving. Moreover, issues about linear induction motor intrinsic features, such as traction force and current, are presented. The linear induction motor (Patent No PI 1103525-0) was tested in various operating conditions. The results contribute to its improvement and to delineate its applicability, not only in MagLev Cobra, as in other vehicles types and industrial applications.

Variable speed synchronous condenser using doubly-fed induction machine

The wound rotor induction machine (WRIM) presents characteristics that make it attractive as an energy storage system where the energy is stored as kinetic energy in the rotor moving parts. When operating in the doubly fed mode (DFIM), with the rotor fed by a variable frequency power converter, the WRIM behaves as a synchronous machine, differing from the latter in the variable speed operation and larger dumping effect when subjected to disturbances. As the converter only needs to be designed to handle a fraction of the total power, the system can be used at a high level of power. This paper presents the analysis of a Doubly Fed Induction Machine (DFIM) used as a controlled active and reactive power compensator. The simulation and experimental results obtained show that this system can be used for voltage control in a power system as well as load-leveling device.

External rotor switched reluctance machine for a kinetic energy storage system

This paper presents the design steps of a switched reluctance machine, as the specification of its basic requirements, the electromagnetic design, the modeling and the validation through magnetostatic and dynamic finite element simulations method. The switched reluctance machine has an external rotor that should operate up to 50,000 revolutions per minute and is applied as a flywheel in a Kinetic Energy Storage System. A rated load of one kilowatt is supplied by the flywheel through a 300 volt direct current link.

Stator flux orientation control of the cascaded Doubly Fed Induction machine

Doubly Fed Induction Generator (DFIG) have many industrial applications and are also used as Wind Power generators. The brushes, required to connect the energy supply to the rotor, are the main drawback of these machines. Therefore there are interest in replace this generator by Brushless Doubly Fed Induction Generator (BDFIG). The Cascaded Doubly Fed Induction Generator (CDFIG) can be used as a starting point in the study of the BDFIG. This paper presents studies of the CDFIG dynamics under vector control based on the Power Machine stator flux. The vector control is divided in two parts: current control loop and power control loop. The vector control and the power flow are verified by experiments and the results indicate the viability to use the CDFIG as a variable speed generator.

Regenerative braking of a linear induction motor used for the traction of a MagLev vehicle

This paper presents the analysis and results obtained with the regenerative braking technique applied to the linear induction motor used for the traction of MagLev-Cobra, an urban transportation vehicle. The converter with bidirectional power flow and the technique used to drive are presented.