Induction Motor

Two original numerical techniques are developed for the finite element (FE) transient analysis of induction and permanent magnet motors operating in demanding aerospace applications. The first technique is the electromagnetic and thermal analysis weak coupling using a multiple slices 2D FE model. The advantage of the specific technique is the representation of complex actuator geometries including skewed magnets and winding ends, by using a low computational cost 2D model while taking into consideration temperature dependent material attributes. The second technique consists in the development of properly defined boundary conditions for the emulation of the cooling housing of actuators. Those boundary conditions are applied at the outer surface of the actuators in contact with the housing and eliminate the need of modeling complex 3D geometries of highly integrated actuator housings.

This paper describes a generalized model of the three-phase induction motor and its computer simulation using MATLAB/SIMULINK. Constructional details of various sub-models for the induction motor are given and their implementation in SIMULINK is outlined. Direct-online starting of a 7.5-kW induction motor is studied using the simulation model developed.

When supplying an induction motor by a PWM-inverter through long cables, reflections occur. Besides the well-known overvoltages at the motor side, stair stepping can occur at both inverter and motor side. These reflections cause EMI in the range of several 100 kHz up to several MHz. The stair stepping reflection phenomenon occurs at the commutation from IGBT to diode. The stair stepping phenomenon depends on the magnitude of the current, the cable impedance and on the dead time of the IGBT gate-signal. The reflection phenomenon increases the turn on time of the diode. In this paper, stair stepping is explained and further investigated through simulation.

Fuzzy logic control is one of the most interesting fields where fuzzy theory can be effectively applied. Fuzzy logic techniques attempt to imitate human thought processes in technical environments. In doing so, the fuzzy logic approach allows the designer to handle ...

Director torque control (DTC) is a well-known scheme for induction motor drives. It is characterized by variable inverter switching frequency, high torque ripples and high sampling requirement due to delay in the system. A triangular wave is used as dither injection signal in order to minimize the impacts of flux and torque ripples in a three-level inverter-fed induction motor drive. This in essence does not impact on the dynamic performance of the system. When the system is on free running condition, it will enable estimation of optimum value of dither frequency and magnitude. It is expected that the proposed technique would reduce the impact of torque ripples by about 60% when compared with the case without dither injection technique. The propose technique will also reduce acoustic noise and increase switching frequency of inverter. DTC induction should not be used under low speed region, otherwise, it would result in poor performance which is caused by stator flux demagnetization that varies with resistance.

The reliability of a motor control based on a variable speed drive is an important issue for industrial applications. Most of these machines are inverter based induction motors and are used in specific and complex industrial installations. Unlike the induction motor, the feeding part is very delicate and sensitive to faults. In order to improve system performance, it is therefore very important for a researcher to know the impact of a fault on the whole of his drive system. This paper discusses the short-circuit fault of the DC-link capacitor of an inverter fed induction motor. The simulation results of this type of faults are presented and its impact on the behavior of the rectifier, the inverter as well as the induction motor analyzed and interpreted.

— This Paper proposed a new navigation method for indoor mobile robots. The robot system is composed of a Radio Frequency Identification (RFID) tag sensor and Ultrasonic sensors. The RFID tags are used as landmarks for global path planning and the topological relation map which shows the connection of scattered tags through the environment is used as course instructions to a goal. The robot automatically moves along hallways using the scanned range data until a tag is found and then refers to the topological map for the next movement. Our proposed technique would be useful for real-world robotic applications such as intelligent navigation for motorized wheelchairs, surveillance and security purposes and in Nuclear power plants where humans are prone to harmful radiations.