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The problem of controlling load perturbed induction motors is tackled by means of an observer based robust discrete-time control. In this scheme, model uncertainties and external disturbances are included in a general additive disturbance input which is to be on-line estimated and subsequently rejected via the controller actions. The observer carries out the disturbance estimation, thus reducing the...
The ride-through capability issues associated with adjustable-speed drives (ASD) have become an important area of concern due to the susceptibility of ASD to power interruptions. Furthermore due to the absence of the dc link capacitor in matrix-converters (MC), MC adjustable speed drives are more vulnerable to such power disturbances. This paper presents a study of a ride-through strategy for MC adjustable-speed...
This paper proposes a simple current error space vector based hysteresis controller for two-level inverter fed Induction Motor (IM) drives. This proposed hysteresis controller retains all advantages of conventional current error space vector based hysteresis controllers like fast dynamic response, simple to implement, adjacent voltage vector switching etc. The additional advantage of this proposed...
In this paper a stator fault detection method based on monitoring of the phase shift between the line currents and phase voltages of the converter-fed induction motor is presented. The phase shift analysis is used as an indicator of the stator-fault-progression level. The mathematical model of induction motor, which includes the stator-winding fault is presented. The fault level is modeled by change...
Circulating currents have been experimentally observed in pulse-width modulated ac open-end winding drives. These currents have the effect of increasing conduction losses in the stator winding resistance of the ac machine. Two major causes for these currents have been identified as device voltage drops in power semi-conductor devices and dead-time used for over-current protection. Analysis of these...
Due to the harmonic content of the distorted supply voltage, the iron losses of PWM inverter fed induction motors are greater than the iron losses measured with sinusoidal supply. The prediction of this loss increase has been the subject of many studies, but it can be still considered as an open research field, in particular when fast and reliable estimation methods are requested. In the paper a previously...
In almost every permanent magnet (PM) excited machine, detent forces arise, which are caused by the permanent magnets in connection with the iron core. In case of permanent magnet linear synchronous motors (PMLSM), two sources of detent forces have to be taken into account: Cogging forces based on the stator slots and detent forces caused by the end effects. Both forces have a negative influence on...
The reliability of the PMSM drives is the one of critical factors in several industries, in particularly, the areas where the precise operation and/or high performance are required. This paper proposes a novel diagnosis scheme using Extend Kalman Filter (EKF), especially, in subject to the open-phase faults of the inverter switches. The stator resistances of PMSM are estimated by the EKF in real time...
In high-power current-source inverter (CSI) fed drives, reduction of losses in semiconductor devices and dc-link inductor through the dc-link current minimization is one of the primary goals. In this paper, a control strategy for the high power CSI-fed interior permanent magnet (IPM) drive is proposed for this purpose. This control strategy keeps the dc-link current at minimum level without exceeding...
Aim of the paper is to evaluate a particular aspect of the design of axial flux permanent magnet (AFPM) machines, i.e. the use of SMC wedges to close stator slots. This contribution is the continuation of a previous investigation dedicated to the analysis of the no-load performance variation introduced by the magnetic wedges. Here, attention is focused on the load performance, by studying the effect...
For the comfort and security of users, noise of electric motors is a critical issue. The harmonic content of the magnetic pressure inside the air gap being the source of the sound radiated by the stator, it suits to know the impact of field weakening. We will show that for some load angles the pressure harmonics change so that the field weakening could be heard.
During the last years the applications for material processing and transportation based on linear motors increased in many industrial fields. A highly modular topology of a linear servo-drive system based on permanent magnet synchronous linear motors is presented here. The proposed system topology differentiates itself from other linear drive topologies through its scalability, so that the system...
Detection of rotor bar asymmetries in induction machines operated by an inverter can be difficult due to disturbances introduced by the fast switching power devices. Furthermore interference of the fault indicator with control dynamics of the load level lower the accuracy of most detection methods proposed. These disturbances can be avoided if the detection can be realized at standstill of the drive...
Spiral motor, a novel high-thrust linear actuator with high backdrivability, consists of a helical structure stator and mover. Under proper gap control against the load fluctuation, the mover moves helically in the stator and the linear motion is extracted to drive the load. Thus, the motor realizes direct-drive motion without mechanical gears. In this paper, an exact feedback linearization engaged...
The stator inter-turn faults and stator electrical asymmetries such as stator resistance and inductance unbalance generate similar negative sequence current signatures in the induction machine. Hence the stator inter-turn fault is one of the most difficult faults to discriminate and detect in an induction machine. Discrimination of the stator inter-turn fault from stator electrical asymmetry essentially...
Coordinate Rotation Digital Computer (CORDIC) is usually used to obtain the angle information without any multiply and division operations. The extended electromotive force (extended-EMF) in the literature shows that the angle error between the rotor reference frame and the assumed reference frame can be estimated from an arctangent function and a division. In this paper, the sensorless control for...
In order to meet industrial safety standards in eccentric presses, the detent force of the acting high force tubular permanent magnet linear synchronous machines (PMLSM) should be reduced. The detent force is caused by two components: the slot effect and the end effect. Both effects are based on the reluctance change between permanent magnet (PM) and stator teeth. The slot effect is already optimized...
A new hybrid excitation permanent machine-doubly fed hybrid excitation permanent magnet synchronous machine without rotor winding is presented. The structure, mathematic model and operation principle of the machine are introduced. It is shown that excitation regulation can be realized by changing the current of stator control winding. The field control performance in the generator and motor operation...
This paper presents an analysis of the torque ripple of a six-phase fault tolerant permanent magnet synchronous machine (PMSM6) for electrical power steering system (EPS) applications. Opened stator phase is the realistic fault condition that can be imagined for a machine fed by a power converter drive system. The behavior of the machine was analyzed under three different winding fault conditions...
This paper treats a disturbance cancellation problem for minimizing the effects of reaction forces on position accuracy of a clean-room robot applied with magnetic bearings. The robot is composed of a main body and a ladder arm, and moves without friction at joints owing to magnetic support. The support stiffness is, however, weaker than the conventional bearings, and the ladder arm moves in reaction...
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