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Discusses the 27 papers in ISEF 1999 Proceedings on the subject of electromagnetisms. States the groups of papers cover such subjects within the discipline as: induction machines; reluctance motors; PM motors; transformers and reactors; and special problems and applications. Debates all of these in great detail and itemizes each with greater in‐depth discussion of the various technical applications and areas. Concludes that the recommendations made should be adhered to.

When induction motors are considered, there is no specific cost model for net savings per year due to condition-based maintenance (CBM) covering various parameters such as downtime, energy, quality, etc. The purpose of this paper is to develop a cost model for the financial viability of the implementation of CBM for induction motors.

A literature review has been carried out to identify the existing failure modes of motor, available condition monitoring techniques, the usefulness of CBM and different maintenance models available. Then, a cost model considering all parameters has been proposed.

A cost model has been proposed for the maintenance of induction motors. Method for the economic evaluation of the model has also been suggested in the paper. The application of the model has been illustrated through a case study of a steel plant, which suggests that investment in the condition monitoring of induction motors increases the net profit of the organization.

The proposed model is specifically designed for induction motors. All the motors under consideration are assumed to be of the same specifications, and fault in any motor is supposed to have the same effect on quality, cost, criticality, etc., of the operation and end product.

This paper will help the maintenance manager in decision making when maintenance action has to be carried out for a given motor under CBM for the better utilization of the equipment and resources. This paper also shows how to compute ROI on CBM investment.

The paper provides a cost model for the economic evaluation of implementing CBM for induction motors which will be useful to researchers and maintenance managers in effective decision making and maintenance planning. The methodology and the cost models are the original contribution of the authors.

The purpose of this paper is to study the development of novel multiphase induction motor (MPIM) with copper die cast rotor in the drive system of electric propulsion vehicles (EPV). It is estimated that the manufacturers are concerned about high torque,Efficiency, motor life, energy conservation and high thermal tolerance. To ensure maximum torque and efficiency with multiphase winding and copper die cast technology to increasing high thermal tolerance, life, energy conversations. On other hand, it is very important of EPV application.

The focus of the investigation is threefold: the modified method carried out on MPIM both stator and rotor can overcome the current scenario problem facing by electric vehicles manufacture and developed perfect suitable electric motor for EPV applications. The design and simulation carried out finite element method (FEM) that was more accurate calculations. Finally developed prototype model of MPIM with copper die cast are discussed with conventional three phase Die casting Induction motor.

The paper confirmed the multiphase copper die-cast rotor induction motor (MDCrIM) is providing better performance than conventional motor. Proposed motor can bring additional advantage like heat tolerances, long life and energy conversations.

The experiments confirmed the MDCIM suitable for EPV Applications. The modified MDCIM of both stator and rotor are giving better result and good performance compared to conventional method.

This paper seeks to investigate the performance of a DTC strategy dedicated to the control of four‐switch three‐phase (B4) inverter fed induction motor drives. The major advantage of the B4 inverter is the reduced number of the involved power switches which opens up crucial cost benefits.

The principle of operation of the B4 inverter fed induction motor drive is recalled in a first step. Then, the basis of the proposed DTC strategy is presented. Following this, the synthesis of the corresponding vector selection table is carried out considering a subdivision of the space vector plan into sixteen sectors.

It has been found experimentally that the B4 inverter fed induction motor drive offers, under the proposed control strategy, interesting performance.

This work should be extended considering a comparison between the performance of B4 inverter fed induction motor drive under the proposed DTC strategy and those of the B6 inverter fed induction motor drive under the popular Takahashi DTC strategy.

The paper proposes a new DTC strategy dedicated to induction motor drives fed by B4 inverter. This reduced structure inverter is of great interest for large‐scale production industries such as the automotive one as far as cost‐effectiveness is concerned.

This paper seeks to discuss the implementation of the rotor flux oriented control (RFOC) in a four‐switch three‐phase inverter (FSTPI)‐fed induction motor drive.

The implementation is achieved considering a current regulation of the FSTPI. Such a regulation is done thanks to bang‐bang regulators. As far as the FSTPI is fed by a battery pack, the paper considers an electrical equivalent circuit of such a power supply.

Simulation works, carried out considering the case of an ideal model of the battery pack and the case where the electrical equivalent circuit of the battery pack is taken into account, have shown that the drive dynamic performance are practically the same. Furthermore, and in order to highlight the performance of the induction motor fed by a FSTPI, these are compared with those obtained with the induction motor fed by a conventional six‐switch three‐phase inverter (SSTPI), considering both models of the battery pack. It has been found that the drive offers almost the same dynamic and steady‐state performance.

The work should be extended by an experimental validation of the simulation results.

The established results open up crucial benefits from the point of view of cost‐effectiveness and volume‐compactness improvements of induction motor drives especially in large‐scale industries such as the automotive one where electric and hybrid propulsion systems are currently regarded as an interesting alternative to substitute or to assist the thermal propulsion systems.

The implementation of the RFOC in FSTPI‐fed induction motor drives is feasible and exhibits almost the same performance as those obtained by conventional SSTPI‐fed induction motor drives under the same control strategies.

The purpose of this paper is to propose an analytical method for prediction of self‐sustained oscillations that might happen during low‐cost induction motor drive application. This forecast is needed to avoid unwanted oscillations that can be encountered for in fan, compressor and pump drives utilizing open‐loop frequency‐controlled three‐phase induction motor drives.

The paper presents the model of the induction motor drive system that includes inverter switches dead‐time and allows discontinuous current of front‐end rectifier. Stability analysis of proposed model was performed by tracing the eigenvalues of the overall system matrix.

Discontinuous rectifier current at light loads and the dead‐time of the inverter switches are the main sources of undesired low‐frequency self‐sustained speed oscillations in open‐loop controlled induction motor drives. The evaluated risk prediction is a function of drive and motor parameters and load level.

The proposed induction motor drive system model highlights the direct connection between the self‐sustained speed oscillations and the system parameters like inverter dead time, dc capacitor values, motor parameters and motor load level. Good accuracy of instability prediction is verified by dynamic simulation and by extensive experimentation.

This paper aims to propose a novel simple and efficient structure for line-start axial-flux permanent magnet (LSAFPM) synchronous motor, especially regarding the permanent magnets (PMs) demagnetization reduction.

At first, a primitive raw scheme of the new structure for the LSAFPM motor is introduced. Considering this raw scheme, the levels of irreversible demagnetization in various regions throughout the entire volume of each PM are evaluated using 3 dimensional (3D) finite elements analysis (3D FEA) in full loading condition during startup until reaching steady state. Based on the results of these analyses, the primitive structural scheme is then modified through segmenting (cutting into four pieces) each PM from where the worst irreversible demagnetization levels occurred.

As will be demonstrated by the results of 3D FEA, the proposed modified structure is not only capable of successful startup and synchronization of the motor but also it considerably reduces the PM demagnetization level. Thus, the performance of the motor is significantly improved.

The demagnetization of PMs is an important effect in PM synchronous motors, which can greatly affect motor performance. Therefore, it is necessary to be considered in the motor design processes. This effect becomes much more significant in the line-start PM motors because the usual high-magnitude startup induction current produces a strong armature-reaction magnetic field, which may cause the PMs to be irreversibly demagnetized. The approach proposed in this paper provides a structural solution to mitigate the PM demagnetization effect and thereby improve the performance of an LSAFPM motor through modifying the structure of the LSAFPM motor according to an FEA-based PM demagnetization analysis. As a considerable contribution, in this analysis, the variation of demagnetization level between different areas inside each PM is computed and is considered as a basis for proposing an appropriate structural modification to mitigate the PM demagnetization effect as much as possible.

To develop general forms of multiscalar models of the induction motor and to present properties of the sensorless control systems based on such models.

Previously presented multiscalar model of the induction motor based on a stator current and rotor flux vector is generalized as a model of type 1. New model of type 2 is defined for stator current and the vector which is directly controlled by a voltage vector. The above models are applied in a sensorless control system with speed observer. Dynamical properties of the sensorless control systems are investigated by simulations and experiments.

Application of the multiscalar model of type 2 results in higher exactness of sensorless control system than application of the multiscalar model of type 1. Controlled variables are more smooth in transients.

This is not an analytical proof of stability of the control systems.

Provides very useful information for development of sensorless control systems for the induction motor.

This paper extends the known method of nonlinear control of the induction motor to the general form. It is possible to choose the sensorless control system of better properties than those used so far.

A time‐energy optimal position control algorithm based on the Pontryagin's maximum principle is developed for a vector‐controlled induction motor system. The vector‐controlled induction motor is modeled as a second‐order system. Bang‐off‐bang control profile, which operates on the torque current, is found as a minimum time‐energy filter, where the amplitude of the time‐delayed signals are constrained to satisfy the control bounds. The time‐energy objective function subject to the constraints, which satisfy boundary conditions, is solved as a parameter optimization problem by using MATLAB optimization‐toolbox. To corroborate the validity of the results of the parameter optimization problem, an experimental test is performed with a dSPACE control card and 2.2 kW induction motor. Furthermore, the simulation results are verified by the switching function obtained from solving the initial conditions. Finally, the theoretical and experimental results are graphically presented and it is seen that the results are in very close agreement.

To meet the need of reducing the cost of industrial systems, sensorless control applications on electrical machines are increasing day by day. This paper aims to improve the performance of the sensorless induction motor control system. To do this, the speed observer is designed based on the combination of the sliding mode and the fractional order integral.

Super-twisting sliding mode (STSM) and Grünwald–Letnikov approach are used on the proposed observer. The stability of the proposed observer is verified by using Lyapunov method. Then, the observer coefficients are optimized for minimizing the steady-state error and chattering amplitude. The optimum coefficients (c₁, c₂, k_i and λ) are obtained by using response surface method. To verify the effectiveness of proposed observer, a large number of experiments are performed for different operation conditions, such as different speeds (500, 1,000 and 1,500 rpm) and loads (100 and 50 per cent loads). Parameter uncertainties (rotor inertia J and friction factor F) are tested to prove the robustness of the proposed method. All these operation conditions are applied for both proportional integral (PI) and fractional order STSM (FOSTSM) observers and their performances are compared.

The observer model is tested with optimum coefficients to validate the proposed observer effectiveness. At the beginning, the motor is started without load. When it reaches reference speed, the motor is loaded. Estimated speed and actual speed trends are compared. The results are presented in tables and figures. As a result, the FOSTSM observer has less steady-state error than the PI observer for all operation conditions. However, chattering amplitudes are lower in some operation conditions. In addition, the proposed observer shows more robustness against the parameter changes than the PI observer.

The proposed FOSTSM observer can be applied easily for industrial variable speed drive systems which are using induction motor to improve the performance and stability.

The robustness of the STSM and the memory-intensive structure of the fractional order integral are combined to form a robust and flexible observer. This paper grants the lower steady-state error and chattering amplitude for sensorless speed control of the induction motor in different speed and load operation conditions. In addition, the proposed observer shows high robustness against the parameter uncertainties.