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Industrial Electronics, 1998. Proceedings. ISIE '98. IEEE International Symposium on

Date 7-10 July 1998

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  • IEEE International Symposium on Industrial Electronics [front matter]

    Publication Year: 1998 , Page(s): 0_2
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  • Contents

    Publication Year: 1998 , Page(s): v - xvii
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    Freely Available from IEEE
  • Author's index

    Publication Year: 1998 , Page(s): 0_4 - 0_7
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  • An induction furnace employing a 100 kHz MOSFET full-bridge current-source load-resonant inverter

    Publication Year: 1998 , Page(s): 530 - 534 vol.2
    Cited by:  Papers (2)
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    An induction furnace using a current-source, full-bridge load-resonant MOSFET inverter suitable for melting small amounts of precious metal (gold and platinum) is presented. Melting times of 25 seconds were achieved at a power level of approximately 900 watts. A parallel resonant topology was employed to resonate at 100 kHz. The full-bridge or H-bridge output stage was used to provide power input to the load in two quadrants. Two important reasons for utilising the current-fed, full-bridge topology in this application are: (1) it has an inherent short-circuit protection capability; and (2) it has a simple design structure, using few components, which has been proved to be advantageous over the other inverter topologies. The induction-heating load is driven at its resonant frequency, by the inverter. This ensures maximum efficiency and power transfer, with zero voltage switching. A simple but effective gate drive and control timing circuit was applied. The compact layout of the inverter suppressed ringing between parasitic lead-inductance connections and the drain-source capacitance of the MOSFETs. The induction furnace operates effectively in open loop throughout the heating cycle. The performance was tested on a 100 kHz prototype, rated at approximately 1 kW. An analysis and experimental results are presented View full abstract»

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  • Online scheduling of a multi-robot system by using genetic algorithms

    Publication Year: 1998 , Page(s): 709 - 713 vol.2
    Cited by:  Papers (2)
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    This paper proposes an online method to schedule the movement of robots in a multi-robot system. The authors introduce a multi-agent based search method to cope with small modifications of the system during the execution of a schedule which is preliminarily obtained by a genetic algorithm (GA). They apply the method to a welding plant, in which a number of seams are processed simultaneously by several robots, but there is no one-to-one relation between the seems and the robots. A GA is used to assign the welded seams to the robots and to schedule the welding order of the seams of each robot in a way which minimizes the overall welding time. The task of the proposed multi-agent based search method is to cope with troubles of the robots and sudden changes of the seams for which a online modification of the schedule is necessary. As a result of computer simulations, the proposed method shows fairly good results for perturbations in the system during the task View full abstract»

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  • An alternative Chua's circuit implementation

    Publication Year: 1998 , Page(s): 441 - 444 vol.2
    Cited by:  Papers (4)
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    This paper proposes a novel nonlinear smooth function to implement the Chua's circuit. This new function provides a similar smoothness as to the cubic polynomial function, but a faster response and a simpler circuitry can be obtained. Some bifurcation phenomena and the chaotic attractors are observed experimentally from a practical circuit point of view View full abstract»

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  • A digital integrated circuit for switching of parallel connected converters

    Publication Year: 1998 , Page(s): 363 - 366 vol.2
    Cited by:  Papers (1)
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    This paper presents the design of a digital integrated circuit (IC) capable of generating PWM control signals for up to four switching DC/DC power converters. For parallel multi-converter applications, the circuit implements the synchronized voltage mode control. The use of the circuit for controlling a power supply system consisting of four parallel connected buck power converters is described View full abstract»

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  • Model of a laser-frequency measuring device

    Publication Year: 1998 , Page(s): 639 - 642 vol.2
    Cited by:  Papers (1)
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    The authors propose a triple frequency phase range finder in this paper. By utilising three close frequencies, the instrument is able to determine ranges with absolute high precision. At the transmitter, the three frequencies are modulated with a laser beam and the resultant signal propagated. This composite signal (three frequencies modulating a laser beam) is ultimately reflected at the target. On reception, phase measuring circuits determine the phase changes/differences suffered by the individual frequencies and eventually the range is calculated. Because the oscillators may suffer frequency instabilities at times, several readings of the same range are taken before the average is taken to ensure high accuracy. The main advantage of the instrument is that the distance is calculated almost instantaneously without any extra calculations View full abstract»

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  • An automated system for core loss measurement and characterization: a useful tool for high frequency magnetic components design

    Publication Year: 1998 , Page(s): 540 - 545 vol.2
    Cited by:  Papers (2)
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    This paper describes an automated measurement system for core loss characterization in high frequency magnetic components. This system can accomplish these aims, within specified magnetic induction and frequency ranges, and at different temperatures, with high accuracy, due to the techniques used in the acquisition and computation of the waveforms involved in loss calculation. The core loss characterization, obtained by fitting the core loss density (per unit volume) versus frequency and magnetic induction, permits the use of an equation, which is a very useful tool for the design optimization of high frequency magnetic components, such as transformers and inductors for switched mode power supplies View full abstract»

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  • Wire-plug connection status tester

    Publication Year: 1998 , Page(s): 479 - 481 vol.2
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    This paper presents a new method to check wire-plug connection situations that are key in producing high quality wire-plug productions. The method uses wire-plug measurement theory to measure micro-resistance and similarity theory to value the status of plugs. According to this new method, a microprocessor-based intelligent bedstead is designed to test wire-plugs in-group. The test speed of the bedstead is high, up to 10000 strips per day View full abstract»

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  • Genetics-based machine learning approach to production scheduling-a case of in-tree type precedence relation

    Publication Year: 1998 , Page(s): 714 - 719 vol.2
    Cited by:  Patents (1)
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    This paper introduces a method of generating and selecting rules for adjusting the priorities of jobs by using genetics-based machine learning (GBML) techniques. In applying the GBML, the authors use the Pitts approach, where the set of rules (rule-set) are represented symbolically as an individual of genetic algorithms, and the fitness of an individual is calculated based on the makespan of the schedule generated by using the rule-set. They actually carried out computational experiments for several problems, which indicate that the method of applying the GBML is effective for finding good rule-sets View full abstract»

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  • Implementation of a zero average current error control algorithm for inverters using a digital signal processor

    Publication Year: 1998 , Page(s): 450 - 455 vol.2
    Cited by:  Papers (2)
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    Inverter performance is typically measured against its ability to produce a high fidelity output waveform with narrow band switching frequency and fast transient response. The implementation of a new and improved algorithm that belongs to the family of zero average current error (ZACE) methods is reported in this paper. Advantages include microprocessor implementation, efficient computation with decreased computational intensity and software control of operational parameters (such as switching frequency, output frequency and output amplitude). The effectiveness of the new current control algorithm is demonstrated using an experimental concept prototype View full abstract»

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  • Scrap reduction in the rolling of aluminium sheet

    Publication Year: 1998 , Page(s): 634 - 638 vol.2
    Cited by:  Papers (1)
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    The speeding up or slowing down of each new loaded roll in rolling mills are generally not controlled automatically. The operator manually speeds the mill up while keeping several factors such as motor current and load into account. This paper proposes the application of optimal control to the speeding up or slowing down of the mill so that the least strip has to be scrapped View full abstract»

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  • Analysis of a power conditioning system for superconducting magnetic energy storage (SMES)

    Publication Year: 1998 , Page(s): 546 - 551 vol.2
    Cited by:  Papers (10)
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    A power conditioning system (PCS) which can be utilized for the compensation of nonlinear and pulsating loads is analyzed in this paper. The PCS consists of a voltage source inverter and a DC current chopper, and uses a SMES as its energy storage device. The whole system is controlled by three regulators acting on the superconducting coil stored energy, the DC-link voltage, and the inverter AC currents. Numerical simulations have been carried out by PSpice to verify the performance of the PCS in different operating conditions View full abstract»

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  • Optimal ordering method for coupling point production control system

    Publication Year: 1998 , Page(s): 568 - 572 vol.2
    Cited by:  Papers (2)  |  Patents (1)
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    In the coupling point production system (CPPS), inventories are concentrated at the position where supply lead time and demand lead time are equal. Inventory and production planning are made at this position. This position is defined as the “coupling point” (CP). In a CPPS, different products may have the same coupling point on the same production line. The authors propose an optimal ordering method (OOM for CPPS) to prevent running out of stock and to limit re-order quantities. This new method has been applied to a window frame manufacturing process successfully View full abstract»

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  • Quasi-resonant circuit DC-link inverter using a zero average current error control algorithm

    Publication Year: 1998 , Page(s): 456 - 461 vol.2
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    A full-bridge bi-level inverter using a quasiresonant circuit DC-link to implement soft-switching is presented in this paper. It is demonstrated that the zero average current error algorithm digital time control can provide a suitable interface between the quasi-resonant circuit DC link and the inverter. Experimental results for a low power single-phase current-controlled inverter are documented, including quasi-resonant circuit waveforms, inverter waveforms and electromagnetic interference spectral characteristics View full abstract»

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  • A 3D image mosaicing system using the factorization method

    Publication Year: 1998 , Page(s): 674 - 678 vol.2
    Cited by:  Papers (2)
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    Recovering the 3D structure of a dynamic scene from an image sequence is one of the most exciting and extensively studied issues in computer vision. The authors present a shape recovery system based on the factorization method which is able to determine the 3D shape of selected feature points. The algorithm is able to maintain shape representation in a recursive way, even when parts of the objects are occluded or leave the field of view View full abstract»

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  • Crew operation scheduling using state selection method and relaxation search method

    Publication Year: 1998 , Page(s): 726 - 731 vol.2
    Cited by:  Papers (2)
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    Railway crew operation scheduling is a problem in that the schedule of crews is scheduled according to a train timetable, whilst satisfying constraints such as working hours, rest hours etc. The authors propose a method which is made up of two phases: an initial scheduling phase; and a modification phase. In the first phase, the state selection method is used to satisfy the meal break constraint and knowledge for satisfying the meal break constraint is created. In the modification phase, a relaxation search method is created to dissolve other constraint violations. Exchange rules for dissolving constraint violation are created. This method is applied to a real rail timetable in order to show its usefulness View full abstract»

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  • A new graphic method for stability analysis of speed sensorless FO controlled induction motor drives working at low speed in regenerative mode

    Publication Year: 1998 , Page(s): 380 - 384 vol.2
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    In this paper, a graphic method to analyze, on the torque versus speed plane, the stability of a speed sensorless field oriented (FO) controlled induction motor drive is proposed. A decoupling control is used to generate the voltage commands from the current commands instead of the traditional current regulators. The speed is estimated using a Luenberger speed observer, that has been simplified taking into account the decoupling control equations. Special attention is given to the stability of the drive operation at low speed, in regenerative mode. This makes the proposed method interesting when the sensorless drive control has to be designed, for example, for electric vehicles applications. The proposed method has been simulated and the results obtained are shown in this paper View full abstract»

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  • A non-linear control of robot manipulators driven by induction motors

    Publication Year: 1998 , Page(s): 513 - 518 vol.2
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    The authors present in this paper a new asymptotically stable scheme for the motion control of rigid robots with induction motor drives. The result is established considering a model that includes the electrical and mechanical dynamics of the induction motors, as well as the full rigid body dynamics of the robot manipulator. The procedure they follow consists of four steps. First, they design an inner control loop such that the overall system becomes a cascade connection of two nonlinear subsystems, i.e., the motor electrical dynamics and the robot mechanical system. The output of the first subsystem, that is the generated torque, drives the robot dynamics, and the other crosscouplings are removed. Second, the torque required to track the desired joint trajectory is evaluated by a passivity approach. Third, they define a desired current behavior which reflects an objective of attaining field orientation. Four, they design a controller that insures the torques generated by the motors asymptotically track the desired torque. Parameters of both robot and motors are known. The local stability is obtained for a controller with a nonlinear observer of rotor motor currents. Simulation results are presented with a robot SCARA to illustrate the performance of the control law View full abstract»

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  • Reluctance synchronous machine drive for hybrid electric vehicle

    Publication Year: 1998 , Page(s): 367 - 372 vol.2
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    The reluctance synchronous machine drive is amazingly not mentioned in literature as a possible alternative drive for electric vehicle propulsion. The paper describes the use of a small, compact reluctance synchronous machine drive for a series hybrid electric vehicle. The advantages and disadvantages of this drive compared to other drives are highlighted. It is shown that a finite element optimum designed flux barrier rotor reluctance synchronous machine has good torque density and efficiency. The machine is current angle-controlled for maximum torque per ampere or minimum kVA. This ensures that the machine is operated reasonably close to optimal efficiency for all loads. The simple drive controller together with an optimum layout three-phase IGBT inverter forms a compact power controller for the vehicle. The calculated and measured results of the reluctance synchronous machine drive system for the electric vehicle are given. The 28 kW peak reluctance synchronous machine is used to drive the front wheels of a sedan, series hybrid electric vehicle through a differential with a gear ratio of 4.5:1. Simulation results show, amongst others, that with the single RSM drive generating a peak torque of 120 Nm, the 1445 kg vehicle accelerates from 0-80 km/h in 25.5 seconds. The maximum speed is 120 km/h View full abstract»

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  • Bare shaft testing of rotating DC electrical machines using digital measurements and optimisation techniques

    Publication Year: 1998 , Page(s): 653 - 656 vol.2
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    With the recent improvements in digital measurement techniques and modelling of electrical machines, researchers have focused on the possibility of commissioning, testing and condition monitoring AC electrical machines. Papers appeared in the literature from the mid 1980s. More recently, in the 1990s, interest has arisen for the bare-shaft testing of electrical machines. Most of the work reported has been in connection with induction machines. However, DC machines are a strong market contender, especially for low-voltage, mobile applications. In this paper, work is reported on DC machines, where a system for bare shaft testing has been developed. The theory used is explained and demonstrated by simulation. The paper concludes on the usefulness of the method and indicates areas for future work View full abstract»

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  • Scheduling of cogeneration facilities operating under the real-time pricing agreement

    Publication Year: 1998 , Page(s): 390 - 395 vol.2
    Cited by:  Papers (1)
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    South Africa's largest electricity supply industry (ESI), Eskom, has introduced a pilot project aimed at developing and introducing a real-time pricing (RTP) tariff to its customers. The potential electricity cost savings that this tariff will have on the cogeneration industry is modelled. The purpose of this study is to add more insight into the basic concepts surrounding the scheduling of cogeneration. The system configuration is discussed and simplified. The schematic model configuration show the model's input-output characteristics. The model consists of an energy and cost fraction section. After modelling the generation and steam shifting operations, the cost of electrical energy due to the implementation of the RTP tariff structure is calculated from the model. This cost is compared with the cost of energy after optimal Nightsave (Eskom's two-part demand and energy tariff) scheduling is carried out. The advantages that the RTP tariff holds for industries with cogeneration facilities is also discussed View full abstract»

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  • Hierarchical genetic fuzzy controller for a solar power plant

    Publication Year: 1998 , Page(s): 584 - 588 vol.2
    Cited by:  Papers (5)
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    To regulate the significant variations of the dynamic characteristics of the distributed collector field in a solar power plant, in this paper, a unique hierarchical genetic algorithm (HGA) has been employed for the design and optimization of the fuzzy logic controller for this purpose. This method not only fulfils the required performance, but also minimises the number of fuzzy membership functions and rules applied. This can be a valued asset for the design of a simple hardware implementable fuzzy controller View full abstract»

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  • Face recognition in a heterogeneous population

    Publication Year: 1998 , Page(s): 594 - 599 vol.2
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    Face recognition technology has many and varied applications, ranging from document verification to crowd surveillance. The use of face recognition technology in access control is, due to its nonintrusive nature, extremely promising. Most face location and segmentation algorithms proposed in the literature have very limited capabilities, with most not able to find a face which is either rotated or scaled. A novel segmentation algorithm which attempts to overcome these restrictions was developed and used in this study. The Eigenface approach (Karhunen-Loeve transform) has been shown to work extremely well when used to extract feature vectors from a face image. It was found to be the most promising of all the published methods and was therefore used. Most face recognition papers in the open literature have generally used Caucasian faces to test their algorithms, no special mention is made of the other population groups. The effect of a heterogeneous population on face recognition is therefore something of an unknown quantity. It is the aim of this paper to investigate the performance of the developed face recognition system, with emphasis on the effect of a heterogeneous population View full abstract»

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