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New Publications are available now online for this publication.
Please follow the links to view the publication.VMS effectiveness under influence of time control
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.1393
To establish the best induction time model of variable message signs (VMS), and based on the optimum system theory, this paper uses a stated preference(SP) survey method to collect the VMS valid data of the road section and adds the time control theory to the use of VMS in order to solve the congestion caused by the overreaction of information. Finally, the paper simulates road network situations in three conditions: the non-VMS induction, the VMS induction without time control, and the VMS induction with the time control. In the contrastive analysis of the three kinds of situations, using AIMSUN is to simulate the situation with time control and without time control. The result indicates that the use of the VMS reduces the traffic jam; the effective time control may greatly enhance induction validity of VMS, especially under the serious traffic accident conditions; the time to get the traffic on the move again for VMS induction with time control is reduced by nearly half compared to the VMS induction without time control. This conclusion may provide reference for the traffic management bureau's routine work.Microscopic simulation on ticket office of large scale railway passenger station
http://dl-live.theiet.org/content/conferences/10.1049/cp.2011.1374
In order to accurately value the performance and service level of ticket office of large scale railway passenger station, the passenger behavior characteristics of ticketing process were analyzed and the simulation conceptual model on ticket office was presented. The model of the ticketing individual behavior logic and quantitative indicators were developed based on SIMIO simulation software from the microscopic view. Taking the south ticket office of Dalian Railway Station as an example, three experiment schemes were designed. Simulation result shows that there were significant differences in the output performance indexes between the three programs with the same input. The simulation based on the individual behavior reproduces the self-organization phenomenon successfully, the 95% confidence interval of ticketed passenger number is [13778, 13986], so the situation of ticketed passenger number in traditional method exceeds the practical scope is avoided.Eigenstructure Control Algorithms: Applications to aircraft/rotorcraft handling qualities design
http://dl-live.theiet.org/content/books/ce/pbce074e
<p xmlns="http://pub2web.metastore.ingenta.com/ns/">Eigenstructure control involves modification of both the eigenvalues and eigenvectors of a system using feedback. Based on this key concept, algorithms are derived for the design of control systems using controller structures such as state feedback, output feedback, observer-based dynamic feedback, implicit and explicit modelfollowing, etc. The simple-to-use algorithms are well suited to evolve practical engineering solutions. The design of control laws for modern fly-by-wire high performance aircraft/rotorcraft offers some unique design challenges. The control laws have to provide a satisfactory interface between the pilot and the vehicle that results in good handling qualities (HQ) in precision control tasks. This book, through detailed aircraft and rotorcraft design examples, illustrates how to develop practical, robust flight control laws to meet these HQ requirements. This book demonstrates that eigenstructure control theory can be easily adapted and infused into the aircraft industry's stringent design practices; therefore practicing flight control engineers will find it useful to explore the use of the new design concepts discussed. The book, being interdisciplinary in nature, encompassing control theory and flight dynamics, should be of interest to both control and aeronautical engineers. In particular, control researchers will find it interesting to explore an extension of the theory to new multivariable control problem formulations. Finally, the book should be of interest to graduate/doctoral students keen on learning a multivariable control technique that is useful in the design of practical control systems.</p>Validation of developed grey-box model of distribution network cell
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0853
The paper presents detail parameter identification procedure and validation of dynamic equivalent model of Distributed Network Cell (DNC) developed based on grey-box approach. The aim is to demonstrate that the equivalent model based on grey-box approach has the potential to significantly improve the modelling capabilities and model accuracy compared to the black-box modelling. The equivalent model consists of a converter-connected generator and a composite load model in parallel. It is presented in six-order nonlinear state space form. The model is evaluated by comparing the responses of case study DNC obtained using non linear simulations in DigSILENT and those obtained by the model. (6 pages)A filtered tuning method for a GPC controller
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0509
This paper presents a new tuning method based on model parameters identified in closed-loop. For classical controllers such as PI(D) controllers a large number of simple tuning methods for various application areas exist. However, when it comes to designing a generalised predictive controller (GPC) four parameters have to be specified. To choose those parameters is not a trivial task since they are not directly related to control or regulation performance. The presented tuning method exploits model-parameters to select suitable controller parameters. Additionally, a Rhinehart filter is incorporated in the design to decrease the impact of noise, therefore, a fifth parameter has to be optimised. The proposed method has been tested in simulation and on a real system.Synchronous machine parameter identification using particle swarm optimization
http://dl-live.theiet.org/content/conferences/10.1049/cp.2010.0061
Synchronous machines are the most widely used machines in power generation. Identifying their parameters in a non invasive way is very challenging due to the inherent nonlinearity of machine performance. This paper proposes a synchronous machine parameter identification method using particle swarm optimization (PSO) with a constriction factor. The PSO allows a synchronous machine model output to be used as the objective function to give a new, more efficient method of parameter identification. This paper highlights the effectiveness of the proposed method for the identification of synchronous machine model parameters, using both simulation and manufacturers measured experimental data. The paper will also consider the effectiveness of the method as the number of parameters to be identified is increased. (4 pages)Electromagnetic engineering simulation techniques using parallel EM simulation tools
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1334
In this paper, we present some basic ideas to use EM software package to accurately simulate the EM problems. The basic procedure in the EM simulation includes excitation setting, mesh design, boundary setting and parallel processing design for a parallel code. In the paper, we introduce some simulation techniques using different software packages and use these software packages to simulate some typical examples.A correction model of loaded train's grade resistance calculation
http://dl-live.theiet.org/content/conferences/10.1049/cp.2009.1626
It is important to validate the train movement simulation model according to the reality. Inaccuracy of train grade resistance model is confirmed to be the important reason of the error by some experiments. With a lot of research on the impact of track layout to the calculation error of train grade resistance, some results have been obtained in this paper. First, calculation error of train grade resistance is able to be ignored on even tracks. Second, notable errors are usually happened when loaded train runs on steep gradient tracks. Third, the specific grade resistance is always smaller than permillage of the grade under the condition that the gradient exceeds 5<sup xmlns="http://pub2web.metastore.ingenta.com/ns/">0</sup>/<sub xmlns="http://pub2web.metastore.ingenta.com/ns/">00</sub>. Finally, new model is proposed, which can be used to correct the errors of loaded train's grade resistance calculation. Based on a lot of verifications, the average of the calculation errors decrease from 9.1% to 3.6%.Driver model simulation for railway brake systems
http://dl-live.theiet.org/content/conferences/10.1049/ic_20080332
This study proposes an essential issue to construct a driver model for a railway in order to keep a safe and integral society throughout the world. As of now, no study has been made on the transfer function of train drivers and brake systems as to safety of a railway. This paper describes the stability and safety of railway vehicles controlled by train drivers. The driver model used the model as proposed by Iguchi et al., and used the transfer function that consisted of the proportion, differentiation and the integrated operation. This study describes the frequency characteristics: transfer function from a braking command to error between the reference velocity and real velocity. Moreover, overrun distances against driver model parameters are shown. According to the simulation results, an integral gain of the transfer function of the driver model is important in the brake and vehicle dynamics. (6 pages)A new method for joint frequency-bearing-elevation estimation based on four-order cumulant
http://dl-live.theiet.org/content/conferences/10.1049/cp_20080767
A new method for joint frequency-bearing-elevation estimation based on four-order cumulant is presented. Several cumulant matrices are obtained by exploiting L-shape array geometries, to construct a high-order matrix to estimate three dimensional parameters. The proposed algorithm has the merits of no needing spectral peak searching and the good estimate precision, and it can be employed to white or color Gaussian noise environment. The effectiveness of our method is demonstrated through some simulation examples.A new method for four dimensional parameters estimation of near field sources
http://dl-live.theiet.org/content/conferences/10.1049/cp_20080771
A new method for estimating frequency, bearing, elevation and range of near field sources is presented in this paper. The four dimensional parameters can be estimated by constructing some correlation function matrixes based on second statistics and cross-array in <i xmlns="http://pub2web.metastore.ingenta.com/ns/">x</i>-<i xmlns="http://pub2web.metastore.ingenta.com/ns/">z</i> plane. The proposed algorithm has the merits of low computing burden and good estimation precision. Simulation results show the algorithm's effectiveness.Using mathematical models to guide the simulation of improvised explosive devices in public spaces
http://dl-live.theiet.org/content/conferences/10.1049/cp_20080716
Terrorist attacks, for example in Madrid and London, have increased concern over the threat that Improvised Explosive Devices (IEDs) pose to public safety. Insurgent groups in Iraq and Afghanistan have developed relatively sophisticated tactics, including the use of synchronised attacks with multiple devices that have not yet been witnessed in Europe or North America. Some of these approaches specifically target the fire and rescue services. Computer simulations provide tools that can be used to plan the response to potential attacks. They can be used to work through a range of scenarios so that emergency personnel minimise their vulnerability and mitigate the threat posed to the general public. However, it can be difficult to simulate the range of human behaviours that are seen in the aftermath of terrorist attacks. Similarly, it is unclear how to develop appropriate blast and fragmentation models that capture a range of future Improvised Explosive Devices. The following pages present a brief overview of mathematical models that are being integrated into simulation tools to address these problems. (6 pages)Fault tolerant architecture for motor drive system
http://dl-live.theiet.org/content/conferences/10.1049/ic_20070032
This paper deals with reliability of motor drive systems. It focuses on the switching power converter which is the weakest drive part. It investigates a new architecture which provides intrinsic redundancy. The method used in this fault switch detection and diagnosis is based on a sliding mode observer. The original aspect of this new approach is that the observer influences the control algorithm in order to rule out or accept the possibility of the device failure. This leads to the right decision which induces the rebuilding of the converter topology. This fault tolerant control strategy assures a limp-back operation. (5 pages)Interconnection and damping assignment approach for reliable PM synchronous motor control
http://dl-live.theiet.org/content/conferences/10.1049/ic_20070036
The goal of this paper is to design a high performance speed controller for a PMSM drive. The controller is passivity based using the energy shaping technique namely interconnection and damping assignment. Under some assumptions, a linear controller is derived associated to a non linear observer to estimate the load torque which is unknown. The important point developed in this paper is the proof of the global stability, which is mandatory in a drive especially in embedded or transportation applications where reliability is a key issue. Simulation and experimental results prove the feasibility of the approach. (6 pages)A blind approach to nonlinear system identification
http://dl-live.theiet.org/content/conferences/10.1049/cp_20070120
The paper combines the least squares support vector machines (LS-SVM) with the system output oversampling technique to realize the blind nonlinear system identification. The given distribution of the inputs is employed to perform this novel algorithm. The LS-SVM based mathematical approximation provides an adequate modeling of the unknown nonlinear system given the distribution knowledge of the system inputs. Simulation results demonstrate the effectiveness of this approach.Identification of a time-delayed process model using an overparameterisation method
http://dl-live.theiet.org/content/conferences/10.1049/cp_20070690
An extensive literature exists on the estimation of the model parameters of time-delayed processes. This paper briefly reviews the main overparameterisation methods for the single-input, single output (SISO) and multi-input, multi-output (MIMO) model parameter (and time delay) estimation problem. Subsequently, two algorithms, and their modifications, are discussed, and their performances are assessed in simulation. Results indicate that both the algorithms can suitably identify the model parameters, including the time delay. The third author has taught the method successfully to students taking advanced level control courses at DIT for a number of years; these experiences will be briefly reported. The paper also discusses the advantages and disadvantages of the overparameterisation approach.System identification for mechatronics/electronic-hydraulics servo device based on LabVIEW
http://dl-live.theiet.org/content/conferences/10.1049/cp_20061090
This paper describes the method which is used to identify mechatronics/electronic-hydraulic servo device. Topics covered within this paper include that NI-DAQ analog outputs is used for stimulating controlled object (third-order circuit, ACT of DVD optical pick-up, electrohydraulic servo motor). Then the data of stimulation and response is acquired from DAQ analog inputs to establish a real-time system identification application based on LabVIEW by acquiring and preprocessing stimulation & response data. Finally, the model of controlled objects is obtained and analyzed and verified the on-line. The identified result can supply references to control algorithm research, simulation and the control strategy of system.Root cepstral filtering for improved system identification
http://dl-live.theiet.org/content/conferences/10.1049/cp_20060639
Phase information is seen to be important and decisive for the performance of a variety of signal processing tasks, including biometric data processing and robotics/navigational applications which require correct localization of objects or events. Existing approaches to system identification ignore phase information, under the minimum-phase assumption; yet, it is argued that improved performance can be obtained if phase information is retained. Modelling the impulse response of an unknown system from the observed output signal comprised of periodic input excitations, has traditionally been undertaken in the time domain. A novel method for system identification is proposed here, by undertaking the analysis in the frequency domain and utilizing the properties of the root cepstrum, which is a phase-retaining coefficient. We are able to demonstrate, that by warping the z-plane, the system impulse response will be separated from the problematic excitation. Hence, by moving the excitation zeros 'away' from the unit circle, the system impulse response may be extracted and modelled. Potential applications of our method include processing of biometric signals, where improved speaker identification/verification depends critically on an accurate vocal tract model of the speaker, as well as robotic/autonomous navigation applications, where correct automatic localization of items and/or events depends on the signal or system phase information. (5 pages)Frequency response analysis in diagnosing transformer winding movements
http://dl-live.theiet.org/content/conferences/10.1049/cp_20050062
Diagnosis of transformer winding movements through frequency response analysis, (FRA) relies on correct interpretation of the complex FRA results. Direct and manual comparison between two FRA test results is the current approach used by maintenance engineers and each FRA signature usually contains about 2000 data points. An automatic approach to represent the FRA signature using a transfer function with parameters of the gain, the zeroes and the poles is studied in this paper. The transfer function estimation code is developed in MATLAB and sensitivity study is carried out on the effect of the parameters of the estimated transfer functions.Intelligent Control Systems using Computational Intelligence Techniques
http://dl-live.theiet.org/content/books/ce/pbce070e
<p xmlns="http://pub2web.metastore.ingenta.com/ns/">Intelligent Control techniques are becoming important tools in both academia and industry. Methodologies developed in the field of soft-computing, such as neural networks, fuzzy systems and evolutionary computation, can lead to accommodation of more complex processes, improved performance and considerable time savings and cost reductions.</p>Dynamic simulation of microturbine generation system
http://dl-live.theiet.org/content/conferences/10.1049/cp_20051282
This paper describes the development of a dynamic model of a microturbine system. The microturbine unit consists of a compressor and a turbine connected on a single shaft to a high-speed generator. Moreover there is a combustion chamber, a recuperator and a gas/water heat exchanger. A control system regulates the speed, temperature and the electric power. To control the frequency, voltage and current of the outgoing power, the microturbine uses power electronics. In this paper, the functional theory of each component and its modelling in Matlab/Simulink environment is described. (5 pages)Control Theory
http://dl-live.theiet.org/content/books/ce/pbce064e
<p xmlns="http://pub2web.metastore.ingenta.com/ns/">This fully revised and updated edition of Control Theory: a guided tour addresses recent developments in the field. It discusses how the rise of Hoo and similar approaches has allowed a combination of practicality, rigour and user interaction to be brought to bear on complex control problems and has helped bridge the gap between control theory and practice. The book also examines the effects of the rise of artificial intelligence techniques and the increasing availability of comprehensive software packages.</p>Simulation of SAR for vehicle occupants
http://dl-live.theiet.org/content/conferences/10.1049/ic_20040078
Vehicle and radio-communications equipment manufacturers, as well as those with responsibility for deploying specialist communications systems for vehicle applications, have a duty of care to ensure that the vehicle occupants are not exposed to high field levels from on-board transmitters. Numerical simulation is well suited to the analysis of in-vehicle field exposure issues, offering numerous advantages over experimental methods of evaluation. The paper outlines the development of such a model, and provides illustrative results obtained for both an empty vehicle model excited by a vehicle-mounted antenna (electric field only), and the same model augmented with a numerical model of the driver (electric field and SAR).Power law noise identification using the lag 1 autocorrelation
http://dl-live.theiet.org/content/conferences/10.1049/cp_20040932
This paper describes a new method for power law noise identification, based on the lag 1 autocorrelation function, that can determine the dominant noise type for all common noise processes, from phase or frequency data, for all averaging factors, in a consistent and analytic manner.System identification and modelling of a milk pasteurisation plant
http://dl-live.theiet.org/content/conferences/10.1049/cp_20040592
This paper presents a comparison of models for the behaviour of a high temperature short time (HTST) pasteurisation plant. Three different models are generated using parametric and non-parametric system identification (SI) techniques in both open-loop and closed-loop configurations. The models obtained are based on real-time data from an operational, pilot scale, pasteurisation plant. Model accuracy is evaluated using the real plant in closed-loop with the plant PI controller settings derived from a genetic algorithm design procedure. The results show that a low order model performs better than higher order models based on classical, best-fit techniques.Modelling and Parameter Estimation of Dynamic Systems
http://dl-live.theiet.org/content/books/ce/pbce065e
<p xmlns="http://pub2web.metastore.ingenta.com/ns/">Modelling and Systems Parameter Estimation for Dynamic Systems presents a detailed examination of the estimation techniques and modeling problems. The theory is furnished with several illustrations and computer programs to promote better understanding of system modeling and parameter estimation. The material is presented in a way that makes for easy reading and enables the user to implement and execute the programs himself to gain first hand experience of the estimation process.</p>Intelligent algorithm for PM/DC drive
http://dl-live.theiet.org/content/conferences/10.1049/cp_20040418
This paper presents the digital implementation in real-time of the Haar algorithm as a controller for PM/DC motor. Based on motor characteristics the structure of a new Haar algorithm is developed. This algorithm is based on lifting scheme method. The lifting scheme is often considered as a generalization of wavelet theory, and the domination of second generation wavelet was introduced. The performance of the proposed controller is investigated both theoretically and experimentally. MATLAB/Simulink, the dynamic system simulation, is used for the simulation. For the experimental investigation, a complete system is designed. An auto-transformer 220/80 volts is used. A single-phase half-controlled bridge is designed to control the armature voltage. A card A/D and D/A, 12 bits is used as a conversion from tacho-generator and from PC to the control circuit. The personal computer used is a Pentium III; Visual C is the language of the software implementation. The proposed controller is very simple software implementation. It has been found robust for use in high performance industrial drive applications. There exists an excellent agreement between the simulated and experimental results. (3 pages)Matrix converters for sensorless control of PMSMs and other auxiliaries on deep-sea ROVs
http://dl-live.theiet.org/content/conferences/10.1049/cp_20040374
The paper reports the use of matrix converter technologies for the control of actuators and other auxiliaries on-board work-class, deep-sea, remotely operated vehicles (ROVs). A key requirement for such systems is the ability to sustain operation at high ambient pressures, up to 300 bar, commensurate with operation of ROVs at depths of 3000 m. A principal feature of the paper is the development of model-based sensorless control methodologies for driving permanent magnet synchronous machines (PMSMs) using matrix converters. It is shown that observer-based state-estimation techniques normally employed for sensorless control of PMSMs using voltage source inverters (VSIs) can be readily exported to matrix converter counterparts with minimal additional computational overhead. Experimental results demonstrate circuit functionality consistent with typical operational duties and the ability of the sensorless techniques to provide reliable estimates of machine rotor position under transient load conditions. (6 pages)Determination of machine parameters for internal permanent magnet synchronous motors
http://dl-live.theiet.org/content/conferences/10.1049/cp_20040392
Experimental methods used recently by many researchers for the determination of PMSM parameters have been reviewed. Analysis and experimentations show many shortcomings and inaccuracies involved in those methods. Two novel techniques for better results through the application of linear regression and neural network are presented, and the results from these methods are also included. In addition, computational design values obtained by finite element computations are also compared to the experimental values. (6 pages)Decoupled current source vector control of a 3-phase grid-connected inverter using a novel vector utility observer for synchronization
http://dl-live.theiet.org/content/conferences/10.1049/cp_20040358
The analysis of a novel algorithm based vector utility observer for inverter-grid synchronization is carried out, whereas the decoupled regulation of the instantaneous active and reactive power is achieved by using the Park vector transformation. The effect of the grid harmonics is considered, both in time domain and in transform domain. The digital signal processor based algorithm is implemented in the current source vector control of a simulated 3-phase grid-connected inverter, guaranteeing a unitary power factor if it is desired. Several simulations show the performance of the utility observer proposed, as well as the control of the 3-phase grid-connected inverter. (6 pages)Self-tuning prediction of beamforming vector
http://dl-live.theiet.org/content/conferences/10.1049/cp_20030217
In this paper the use of a self-tuning predictor in antenna array beamforming is examined. Prediction can be used for compensating the delay in beamforming coefficient update if the one of the ends of the radio link is moving fast. Three different prediction model configurations are examined; although all predictions are based on applying a recursive least squares (RLS) method to an auto-regressive-moving-average (ARMA) model. The advantages of the beamforming vector prediction are demonstrated through simple simulations with perfect power control and no multipath components. The signal-to-interference-and-noise-ratio (SINR) is used as the performance measure.Control loop performance assessment using minimum variance benchmarking
http://dl-live.theiet.org/content/conferences/10.1049/ic_20020219
This paper discusses the practical application of continuous performance assessment as a requisite for monitoring and maintaining the advanced process control (APC) assets in the process industry. In this paper complemented with the presentation, the theory of performance assessment is introduced as a technique for continuously assessing the performance of the basic control loops in a plant, as a means towards maintaining APC assets. The continuous performance assessment allows detection of performance degradation in the basic control loops in a plant by monitoring the variance in the process variable and comparing it to that of a minimum variance controller. The resulting index gives an indication of the level of performance of the controller and an indication of the action required to improve its performance, e.g., re-tune the controller or consider process re-engineering. (6 pages)Availability modelling tools applicable to satellite systems
http://dl-live.theiet.org/content/conferences/10.1049/ic_20020063
QinetiQ (pronounced "kinetic") is a limited company wholly owned by the UK Government. It incorporates most of the former research, technology and evaluation establishments of the Ministry of Defence. QinetiQ and its predecessor organisations have played a central role in the development and leadership of the UK space programme for more than 40 years. Space activities in which the organisation is involved, especially in the area of specification and design, are outlined. Currently, QinetiQ has a range of software modelling tools. The tools were designed to examine communication satellites, but could easily be tailored to work with other types of satellite systems. A summary of these models is provided in the paper. (4 pages)Sensorless torque vector speed control of a brushless DC motor
http://dl-live.theiet.org/content/conferences/10.1049/cp_20020169
The research described in this paper was intended to evaluate a minimal-computation sensorless control technique for brushless DC motors. The motor used in the research was a cylindrical machine with surface magnets and air-gap windings. Torque vector control is a computationally economical technique for applying torque and flux control loops to electric motors. In the research described, a digital signal processor (DSP) was used to carry out position estimation and control torque and flux by controlling the drive signals to a conventional three-phase, six-switch IGBT inverter The torque vector concept operates by calculation based on a 2-phase equivalent circuit, producing values of flux magnitude and angle and torque. The torque vector control scheme demonstrated a capability for high bandwidth control, as a sampling time of only 2 μs for the inner (torque/flux) loop was achieved with a DSP which had a 50 ns single cycle execution time. The inverter switching frequency is also minimised by the strategy used.A sensorless speed estimator for the direct torque control of an interior permanent magnet synchronous motor drive
http://dl-live.theiet.org/content/conferences/10.1049/cp_20020168
This paper proposes a completely sensorless interior permanent magnet (IPM) synchronous motor drive with direct torque control, which uses a new speed estimator from the stator flux linkage vector and the torque angle. It is shown that by including the torque angle in the estimation process results in a more accurate transient speed estimator than what is reported in the existing literature. Also, the effect of current measurement error (offset error and scaling error) are analyzed. The offset error causes the torque of a motor to oscillate and these torque ripples deteriorate the performance of the speed estimator. In order to eliminate ripples in the estimated speed, compensation has been made using a programmable cascaded low pass filter. Results from modeling and experiment verify the effectiveness of the sensorless speed estimator and offset error compensator.Sensorless DTC of induction machines with complete core loss compensation
http://dl-live.theiet.org/content/conferences/10.1049/cp_20020096
The paper discusses impact of core loss on sensorless direct torque control (DTC) of an induction motor and develops a modified DTC scheme with full core loss compensation. Core loss is compensated in both the process of torque estimation and speed estimation. A novel modified speed estimator of MRAC type is developed for that purpose. The proposed compensated DTC scheme is verified by simulation.A synchronised multi-motor control system using sensorless induction motor drives
http://dl-live.theiet.org/content/conferences/10.1049/cp_20020086
This paper outlines a high-performance induction motor sensorless control strategy engineered for high speed holding accuracy. The strategy utilises a model-based method, tuned by a speed estimate derived from rotor slot harmonic effects seen in stator quantities. Two 4 kW machines, both running the developed scheme, are speed synchronised using a bi-axial cross-coupled control method. Results are shown to be comparable to those obtained from the same synchronisation scheme, and on the same rig, using encoded indirect rotor flux oriented (IRFO) control.Genetic algorithm based maximum likelihood DOA estimation
http://dl-live.theiet.org/content/conferences/10.1049/cp_20020337
The maximum likelihood (ML) direction-of-arrival (DOA) estimation method was one of the first to be investigated. For a long time, the complexity and computational load of maximizing the multivariable, highly nonlinear likelihood function prevented it from popular. We present the genetic algorithm (GA) for computing exact solutions to the likelihood function with almost guarantee of global convergence. The performance of GA-based ML and multiple signal classification (MUSIC) algorithm have been compared for a variety of scenarios of SNR, DOA separation, number of snapshots, and computational cost. The relationship between the ML technique and MUSIC is also investigated.Prompt identification of weak transmission lines regarding voltage collapse
http://dl-live.theiet.org/content/conferences/10.1049/cp_20020049
In this paper, a practical and simple approach for finding the weakest power transmission line in a power system is proposed to be used. This is the P-Q curve idea. One can create the P-Q curve for each transmission line. The minimal distance from the steady state point to the P-Q boundary curve may be treated as the degree of the voltage security at a given transmission line. Additionally, using the P-Q curves, one can calculate the probability of branch voltage collapse for uniformly distributed active and reactive powers.Speed, flux and torque estimation of induction motor drives with adaptive system model
http://dl-live.theiet.org/content/conferences/10.1049/cp_20020167
This paper deals with the sensorless speed control of induction motor drives. A model for speed, flux and torque estimation is proposed. Its structure is based on the extended Kalman filter theory. Experimental results are presented on a 1.5 kW induction motor drive to demonstrate the excellent system performance.Sensorless vector control of a surface mount PMSM using high frequency injection
http://dl-live.theiet.org/content/conferences/10.1049/cp_20020087
The paper describes a high frequency based position detection observer. The observer detects the natural saliency of a surface-mount permanent magnet synchronous machine (PMSM). Vector control and speed/position estimation was carried out on a single fixed point processor the TMS 320F240.Effect of motor type on performance of sensorless induction motor control using HF injection
http://dl-live.theiet.org/content/conferences/10.1049/cp_20020170
This paper concerns the sensorless control of induction motors at low or zero speed where the rotor or flux position is tracked using high frequency signal injection. The type of motor in use will have a great influence on the effectiveness of these methods. The paper shows that the complex saturation phenomena can severely affect the flux/rotor position estimation. Two methods of signal injection and their respective processing are discussed.Control of an axial airgap machine for an electric vehicle
http://dl-live.theiet.org/content/conferences/10.1049/ic_20010094
This paper presents experimental results obtained from a PM double sided axial field machine with central rotor intended for use in an electric vehicle (EV) direct wheel drive. The configuration represents the stators of the machine being attached to the chassis of the car whilst the rotor directly drives the road wheel. However, perturbation of the rotor while the vehicle is moving will cause torque fluctuations in the machine. It is shown that these torque pulsations can be eliminated by the modulation of the input motor current using a signal obtained from the identification of the flux. (8 pages)The effect of confidence errors on estimation fusion using Bayes' criterion
http://dl-live.theiet.org/content/conferences/10.1049/ic_20010102
Information fusion can be used to combine estimates from different sources to give a single estimate of greater quality. To achieve this, it is often necessary to use confidence measures to gauge the reliability of individual estimates. This paper presents empirical results which suggest that errors in such confidence measures are important when choosing appropriate fusion strategies. (8 pages)Development of a dynamic power system load model
http://dl-live.theiet.org/content/conferences/10.1049/cp_20010567
The paper addresses the issue of measurement based power system load model development. The majority of power system loads respond dynamically to voltage disturbances and such contribute to overall system dynamics. Induction motors represent a major portion of system loads that exhibit dynamic behaviour following the disturbance. In this paper, the dynamic behaviours of an induction motor and a combination of induction motor and static load were investigated under different disturbances and operating conditions in the laboratory. A first order generic dynamic, load model is developed based on the test results. The model proposed is in a transfer function form and it is suitable for direct inclusion in the existing power system stability software. The robustness of the proposed model is also assessed.A time-domain analysis of multiple periodic signals
http://dl-live.theiet.org/content/conferences/10.1049/ic_20000551
Periodic signal analysis is important in many areas such as communications systems, bio-medicine, sonar and radar. Many modelling schemes are used in this analysis and for a real system a period estimation technique must be able to estimate either single or multiple periodicities from sensor data. This estimation process may be constrained by the fact that the periods, periodic waveforms and number of periodicities present are unknown a-priori. It is also reasonable to assume that the sampling rate will not be synchronised to the replication rate of any of the periodic waveforms and that the period and shape of the periodic components will vary with time. We propose a time-domain estimator, for such a scenario. Our time domain estimator is based on a modified incremental multi-parameter (IMP) algorithm. It is able to detect and track several periodic components in a single time series. Two aspects of our method are discussed: (a) a detection and acquisition stage that includes a novel track-before-detect method, to estimate the period and amplitude profile (state variables) of each detected periodic component and (b) a recursive mode for updating the state variables in a real-time practical situation. (10 pages)Identification and validation for robust control: design issues
http://dl-live.theiet.org/content/conferences/10.1049/ic_20000239
Model validation is the exercise of assessing whether a model of some underlying system is good enough. The assessment of the quality of a model cannot be decoupled from the purpose for which the model is to be used. And just as the research on system identification has, in the last 10 years, focused on issues of design in order to obtain a nominal model that suited the objective, so must the validation experiment similarly be designed in such a way that the model is guaranteed to deliver what the model is supposed to deliver. Thus, one must think in terms of “goal-oriented validation”. This presentation focuses on model validation for robust control. The validation step is the ultimate quality control station that allows the model builder to provide the user with certified guarantees about the quality of his/her model. Without such certification the user cannot confidently use the model for his particular application, since he has no guarantees about whether the model is able to achieve its purpose. (3 pages)Induction motor sensorless vector control in the field weakening region
http://dl-live.theiet.org/content/conferences/10.1049/ic_20000383
Speed-sensorless control of induction motor drives has attracted considerable attention in recent past, with a vast amount of effort directed towards providing an accurate speed estimate in the vicinity of zero speed. The problem of speed estimation in the field weakening region has stayed to a large extent beyond the scope of interest. While some of the speed estimation algorithms completely fail in this region, the others exhibit a substantial speed estimation error, caused by de-fluxing of the machine and consequent variation in the magnetising inductance. This paper at first examines, by simulation, the speed estimation error that takes place in the field weakening region when a MRAS based speed estimator, of rotor flux type, is applied. Next, a possible solution to the problem of speed estimation under varying flux conditions is proposed. The speed estimator is modified in such a way that the variation in the instantaneous level of the flux during operation in the field weakening is recognised and properly adapted to at all times. Verification of the proposed scheme is provided by experimentation on an indirect feedforward rotor flux oriented induction machine. (6 pages)Robust parameter identification for virtual test of systems on a chip
http://dl-live.theiet.org/content/conferences/10.1049/ic_20000409
While a circuit's manufacturing yield is high it might be very sensitive to variations in environmental conditions such as power supply and temperature. Such sensitivity causes the circuit to have low operating performance. Systems-on-a-chip will become increasingly complex, with high demands placed an functionality, performance and testing. The method proposed integrates design and test. It is based on analytical modelling to estimate the sensitivity and determine the reliability of analogue circuits in the presence of faults. The implications of this to system on a chip, particularly IP cores is discussed. (6 pages)Sensorless induction motor drives
http://dl-live.theiet.org/content/conferences/10.1049/ic_20000386
The desirability of eliminating mechanical shaft sensors for induction motor drives has led many manufacturers to include sensorless vector drives to their product range. However, current generation sensorless drives are unable to exhibit the same performance as sensored vector drives, particularly at frequencies below a few Hz. This paper reviews current methods and research that may expand the application of sensorless drives into areas that currently require speed sensors. The emphasis of the review is on low speed performance and the inherent problems of model-observer based methods are discussed. In order to overcome these problems, nonmodel based methods relying on the tracking of induction machine saliencies are reviewed. (5 pages)