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EPE-PEMC 2002 - Topic 09: Motion Control
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	A Digital Speed Filter for Motion Control Drives with a Low Resolution Position Encoder   By S. Costantini; S. Bifaretti; A. Bellini	[View]   [Download]
Abstract: In motion control drives, the motor rotation speed measurement is generally obtained by means of an incremental encoder with a limited number of counts per revolution. The encoder furnishes a shaft position measure; therefore, to obtain a speed measure a derivative operation is needed. As consequence, especially at lower speeds, the rotation speed measure results rather noisy and a suitable filter must be used to reduce the noise. The paper deals with the problems connected to the realization of such a filter on a fixed point DSP controller. In particular, a stationary Kalman filter, easily realizable on a digital microcontroller, is carried out; this filter reduce the measurement noise to acceptable values and it can also provides an acceptable estimation of the acceleration.
	A Full State Observer for Sensorless Control of a Salient PMSM   By G. Tadmor	[View]   [Download]
Abstract: A full state observer (including currents) is developed for sensorless control of a salient permanent magnet synchronous motor (PMSM). Ohmic losses minimizing currents simplify observer structure: error dynamics of speed and load estimates are locally decoupled from angle estimates and remain stable at zero speed. The observer does not utilize the usual quasi steady state (constant speed) hypothesis.
	A Fuzzy Solution of Optimal Control Problem with the Quadratic Performance Criteria   By E. Rosu; M. Gaiceanu	[View]   [Download]
Abstract: Both in Europe and in USA, the induction motors are the major energy consumers [1]-[3]. According to the estimation of their power distribution and energy consumption, 83% of the total amount of electric motors is consumed by the 0.75-7.5 kW electric motors in Europe [3]. By using a quadratic energetically performance criteria offered by the optimal control theory [5]-[7] the problem formulation was done with fixed time, free-end point, unconstrained, the matrix Riccati differential equation (MRDE) having to be solved. Consequently, in order to cover all power range in [7]-[9] the optimal control based on energetic criteria for squirrel cage induction motors was synthesized. The optimal control law has three components: the state feedback, the forcing component to achieve the desired state x1 and the compensating feed forward of the perturbation w(t). Obviously, the analytical solution supposes the knowledge of the perturbation w(t)=Tl(t), which could be available by using a torque observer as in [10]. The rotor field oriented induction motor (IM) is controlled at constant flux, the optimal control synthesis consisting of the determination of the stator three-phase currents system, based on the longitudinal and transversal components of the stator phasor current. The purpose of this paper is to implement the optimal control such that the properties of the MRDE solution (obtained from the numerical integration) are maintained, and much more, to extend their availability to nonlinear systems or to the systems in which the parameters are unknown. Therefore, the fuzzy logic approach is shown in this paper. The energetic efficient electric drive (EEED) is designed to deliver the same output power with less electrical power input [11]. The result of EEED using is 8 to 25% units increase in efficiency [11]. Through the normalization process of the input and output variables, the optimal solution becomes available for any type of induction motors power. The optimal control law oriented to the vector controlled induction machine provides dynamic regimes, smooth response, no oscillations of the vector state and of the control on the dynamic period, without overshoot, the fast compensation of the load torque with minimal energy consumption, and robust performances.
	A New Optimisation Algorithm of Position Estimation for Zero- and Low Speed Range Using Magnetic Saliency Method   By R. Filka; B. Dobrucky; M. A. R. Abdalmula; R. Holcek	[View]   [Download]
Abstract: This work presents an improved method for position estimation of permanent magnet synchronous motor (PMSM) at zero speed. It is based on a rotor magnetic saliency when the rotor reactances in d- and q-axes are different, but very close to unity one. The main contribution of the paper is substantial increasing of estimation accuracy by means of optimisation of modulation period and motor parame-ters&time constant, respectively. The optimisation is based on linearization of the stator currents (in d- and q-axes) using minimum possible value of the ratio of modulation period/time constant. The opti-misation algorithm is also supposed for low speed range. Simulation experiments of rotor position estimation have been carried out for two types of permanent magnet synchronous motors.
	A Novel Approach to Step Drive Design Using a Concentrated Parameter Multi-Domain Modeling Approach Including Cogging Torques   By A. Pohl; M. Schulze; O. Hcdrich	[View]   [Download]
Abstract: The design in power electronics and drives requires accurate system behavior prediction. Due to its increasing complexity, the behavior of subsystems of different physical domains has to be considered to examine their interactions. Especially the interactions between the electrical, mechanical, and control systems are of special importance. With modern three-phase step drives cogging torques exert motion ripples on the mechanical subsystem and oscillations on the electrical one. Furthermore, the stepper motor can excite the mechanical train by torque ripples arising from various mechanical and electrical unbalances. The drive designer has to be provided with appropriate simulation tools to tackle this affect on motion quality. This paper first outlines possible simulation strategies. It presents an approach for decomposing a complex drive into subsystems and modeling them in their major physical domains using concentrated parameter simulation. There, the cogging torque property of stepper motors is included. The basic modeling principles of electrical/electronics, mechanical, and control subsystems are shown and equations derived. A complex step drive example verifying measured results concludes.
	A Speed Estimator for High Performance Sensorless Control of Induction Machines Above Base Speed   By M. Wang; E. Levi	[View]   [Download]
Abstract: The paper analyses a modified version of the model reference adaptive system (MRAS) based speed estimator, whose outputs of the reference and the adjustable model are rotor flux space vectors. The estimator is modified in such a way that the variation in the instantaneous level of the main flux saturation during operation in the field weakening is recognised and properly compensated at all times. Verification of the proposed scheme is provided by simulation and by experimentation on an indirect feed-forward rotor flux oriented induction machine for speed references of up to twice the base speed.
	Amphibious-Vehicle Control Method Based on Neural Network Estimation of Underwater Running-Resistance   By K. Yoshida; A. Nafa	[View]   [Download]
Abstract: When running underwater a linear synchronous motor train will face a large running-resistance difficult to evaluate which is mainly due to much stronger hydrodynamic effect than the mechanical friction between guide-rollers and guideway. To evaluate this running-resistance a neural network is designed and trained off-line using experimental data. The trained neural network can evaluate the running-resistance for any demand position and speed patterns within the range of speed limited by the training data. Combining both the robustness of a servo controller and the neural network fast calculation capability, the trained neural network is used as a compensator in a feed-forward control loop to increase the efficiency of the decoupled controller used so far to control marine express 02 for levitation, propulsion and guidance.
	An Extended Sliding Mode Observer for Control of an Induction Motor   By J. M. Retif; G. Clerc; D. Duval; X. Lin-Shi; O. Asseu	[View]   [Download]
Abstract: In this paper, an extended sliding mode observer is proposed for on-line estimation of rotor fluxes and rotor time constant. The simulation and experimental results are presented to illustrate the fast convergence and high robustness of the observer against modeling uncertainty and measurement noise.
	Analysis and Optimization of an Electronic Throttle for Linear Operating Modes   By N. Peric; D. Pavkovic; J. Deur; M. Jansz	[View]   [Download]
Abstract: Electronic throttles are increasingly being used in automotive systems in order to improve vehicle driveability, fuel economy, and emissions. The paper presents an analysis of the electronic throttle body linear model. The analysis results in simplifications of the process model structure and controller optimization procedure. A method of identification of the simplified process model is outlined. A linear feedback/feedforward throttle position controller is algebraically optimized according to the damping optimum. The linear controller is extended with a gain scheduling algorithm, in order to deal with different process parameters for the regions below and above the limp-home position. The proposed controller represents a core of the overall nonlinear electronic throttle control strategy which also includes friction and limp-home compensators. The designed control system is examined by computer simulation and experiment.
	Application of Model Algorithmic Control to AC Servo Drives   By G. Baoming; Z. Hongtao; J. Jingping; S. Pengsheng; W. Xiangheng	[View]   [Download]
Abstract: In the conventional AC position servo drives there exist many drawback, such as the structure of the system is complicated, and its control performances are significantly influenced by various uncertainties. To overcome these demerits, a model algorithmic control (MAC) scheme for AC position servo drives is proposed by synthesizing the advantages of MAC in the model prediction, rolling optimization and feedback tuning in real time on-line. The first order ARMA-model of the AC servo drives is used as the parameter-model in the predictive control, which greatly simplifies the control algorithm that meets the requirement of the real-time control for the split-second dynamics of the motor. Moreover, the optimum control of the servo drives can be insured by the dynamic optimization and feedback tuning based on the predictive model in real-time. The analysis of the system’s stability and robustness shows that the control system has very good robustness in any cases. Experimental results verify the excellent dynamics and static performances of the proposed AC position servo drive.
	Asynchronous Machine Drive System with Multivariable Optimal Direct Torque Control   By G. V. Leandro; J. A. Moor Neto; N. C. De Jesus; M. De Campos; F. Salvadori	[View]   [Download]
Abstract: This paper proposes and investigates a novel Multivariable Optimal Direct Torque Control (DTC) strategy to achieve the decoupling ux and torque control of AC drive system. The proposed control strategy relies upon a multivariable state space controllers. The controller is designed using Linear Quadratic (LQ) optimal control techniques. Simulation and experimental results of the proposed scheme are presented. The presented technique provides good steady-state and fast transient response performance.
	Autotuning Controller with Backlash Compensation   By T. Jukic; N. Peric	[View]   [Download]
Abstract: This paper depicts an implementation of an autotuning controller in a position-controlled system with backlash. The controller operates in three distinguishable phases: linear system parameter identification, backlash identification and invoking a position controller with backlash influence compensation. The influence of nonlinearity was compensated by using a model-based approach. That way, the applicability of a linear full-order state controller, with an additional compensating component of control signal, was extended onto systems with presence of backlash. Compensation method is described in detail in [1], [2]. Considering the fact that system parameters tend to change with time, it was sensible to introduce an autotuning capability to increase the performance of control system. The idea was first tested by means of simulation, followed by experiments on a laboratory model that proved outstanding controller performance.
	Computer controlled harmonious two-coordinate positioning system   By V. Gelezevicius; G. Blaziunas	[View]   [Download]
Abstract: Nowadays the two-co-ordinate servo systems became special and widespread group of multidimensional industrial control systems. They are used for control of various devices in many cases, where the motions of two separate acting drives should be co-ordinately controlled. The strategy of harmonious two-coordinate computer controlled positioning system was proposed in this article. The digital model of harmonious two-coordinate positioning system was created and investigated. Investigations of the digital real-time model, which enables to research behaviour of two-coordinate positioning systems in the conditions maximally approached to the real working conditions, are represented. Harmonization of movements carried out according information about referred positioning displacements and running displacements values were investigated on this real-time positioning system model. Real-time model was build in such way that model part representing the part of control system realized by software means corresponds to control program of the system and may be used for future realisation of real system. From the modelling results it was established that using the sampling time more or equal to 0,01 s the acceptable control quality could be obtained. The obtained modelling results show the efficiency of proposed strategy of real-time model.
	Concerning designing of model of hopping apparatus   By V. B. Larin; V. M. Matiyasevich	[View]   [Download]
Abstract: The statically unstable (one-legged) hopping machine is considered. On this example the estimation of an opportunity of using and efficiency of the control algorithms for systems with variable constraints at engineering realization of the hopping apparatus is executed. The obtained results testify that the control algorithms allow designing the hopping machine by using the simple elements. The dynamic properties of the offered hopping apparatus allow him to increase a horizontal velocity of movement at 2 times during 2…3 steps. This fact is interesting because in this case a linear regulator controls the nonlinear plant.
	Control of A Shape Memory Alloy Driven Robot Hand   By P. Zsiros; P. Korondi; A. Huba; P. Baranyi	[View]   [Download]
Abstract: This paper deals with a humanoid hand moved by artificial muscles, which can be used as a slave device of a telemanipulation system. The main contribution is a practical application of generalised neural networks for a dextrous hand moved by Shape Memory Alloys (SMA). Since SMA have highly non-linear characteristics and their parameters depend on the environment (mainly on temperature) so the robot hand is controlled by a generalised neural network, which can learn the actual non-linear characteristics of the robot hand. The experimental setup consists of a 20 degree of freedom hand moved by SMA string used as artificial muscle.
	Control of DC Drive using Artificial Neural Networks   By M. Kuchar; P. Brandstetter	[View]   [Download]
Abstract: This paper deals with the implementation of artificial neural network in control of DC drive. In the contribution four control systems are discussed. The first is a direct inverse control, then a neural feedforward control with PID controller. The third is a neural network predictive control and the last of them contains a conventional PID controller for future comparison of presented control systems. The DC drives were simulated in program MATLAB with Simulink toolbox, Neural network based control system design toolkit and Neural network toolbox. The main goal of the work was to find the simplest neural network structures with minimum number of neurons, but simultaneously good regulation characteristics are required. Despite used neural network, which is very simple it was achieved satisfactory results. Artificial neural networks are mainly used for complicated systems and processes, which are very difficult to control.
	Controlled Linear Electric Drives   By A. Poska; Z. Savickiene; R. Rinkeviciene	[View]   [Download]
Abstract: When the construction of LIM gives no possibility to reach the required speed if is determined slip of LIM, the LIM must be supplied by voltage with changeable frequency from frequency converter. The paper deals with the properties of low speed LIM. It is proved that LIM current dependence upon slip is negligible. The expressions of characteristics of frequency controlled drives with linear induction motors were derived and analyzed. It is proved the law of changing LIM supply voltage when the frequency is changed and the LIM phase current changes with slip and is constant (does not depend upon slip). It is analyzed control of LIM by changing of voltage also there are presented the results of modeling of low speed LIM operating in start-stop mode.
	Design of a Robust Position Controller for IPMSM by Hybrid Fuzzy Control and Maximum Torque per Input Current   By A. Aarefi; E. J. Abdi; H. Orce; M. R. Zolghadri	[View]   [Download]
Abstract: In this paper, the performance of a fuzzy position controller for a permanent magnet synchronous motor for robotic applications is investigated. A fuzzy logic controller is employed as an outer position loop. Moreover, a PI controller is employed as an inner speed control loop. Simulation results with Matlab Simulink package are presented. They show that the fuzzy controller is robust, that is, it has low sensitivity to parameter variations and high capability of disturbance rejection.
	Direct Torque Control of Induction Motor with Stator Flux Correction   By D. Kruselj; M. Bilic; B. Furcic; V. Siladi; M. Vucetic	[View]   [Download]
Abstract: Direct torque control (DTC) method with correction of stator flux vector is presented in the paper. The correction is made by means of appropriate component of stator current vector. Thus, controlled quantities (electromagnetic torque and stator flux) are estimated only from stator parameters and measured stator quantities, and there is no need to use rotor parameters, which are dependent on the operating condition, and rotor quantities, which cannot be measured. With the proposed method stable operation in whole speed range, robust start−up with slow change of the torque and fast torque response are achieved. Simulations and experimental tests verify the validity of the method.
	Estimation of Induction Motor Variables Based on Artificial Neural Networks   By J. Zilkova; J. Timko; V. Fedak; M. Borbel	[View]   [Download]
Abstract: The paper deals with utilisation of artificial neural networks (ANN) for observing the asynchronous motor variables. The observing is realised utilising several quasi-single estimators and their number is equal to number of observed variables. The observers are based on off-line learning feed-forward ANN and on cascade-forward backpropagation ANN, respectively. Rotor flux, torque and angular speed of an induction motor are estimated. Changes in the rotor resistor do not influence the quality of observing.
	Examination of the Short Circuit Model for Sensorless PM Synchronous Motors with Respect to Torque Ripple, Measurement Period and Model Deviation   By U.-H. Rieder; E. Robeischl; M. Schroedl	[View]   [Download]
Abstract: In many applications, especially for low-cost-drives and systems with limited requirements on position accuracy, mathematical models are used for position estimation. Sensorless control of Permanent Magnet Synchronous Motors (PMSMs) is based on mathematical models. Saliency-based models work well at low speed down to standstill, whereas in the high speed range back-EMF based models can be implemented. This paper presents an extended analysis of the so called “short circuit model” (back-EMF-based). The model deviation caused by the neglected stator resistance at nonzero directaxis current component and saliency effects is derived in detail. Furthermore the minimisation of the torque ripple caused by the short circuit state will be analysed and minimised for highest speed range by measurement period adaptation, so that it is limited (and on request constant) by a determined value in whole operation area. An enhanced short circuit model for high speed range (motoring and generating mode) is implemented at which operation in field weakening area is possible. Combination with the INFORM-method (for low speed range including standstill) results in a sensorless variable speed drive supporting the whole speed and load range.
	Exploring Zero voltage switching in SRM drive design   By S. L. Ho; D. Sutanto; Y. P. B. Yeung; K. W. E. Cheng; Y. Lu	[View]   [Download]
Abstract: This paper describes the soft-switching method of the switched reluctance drives. A resonant pole type switching is used to modify the chopping transistors. Switched-capacitor technique is used to improve the current waveforms. Also, an active-clamp SRM drive is proposed. This circuit has very good zero-voltage switching on transistors except the commutating transistors which still suffering from switching loss. The performance of these two circuits is explained.
	Extended Kalman Filter Based Speed Sensorless AC Motor Control With Parameter Estimation   By D. Fodor; K. Bíró; S. Vajda	[View]   [Download]
Abstract: This paper describes a method for estimating the rotor resistance as a parameter for speed sensorless control of an AC motor. Properly the Extended Kalman Filter (EKF) is used for estimating the state variables and parameters. The EKF algorithm and its adaptation to the motor model is described by rigorous mathematical representation and was realized in MATLAB/Simulink. The results show good dynamic behavior suitable for real-time DSP implementation. The purpose of this work is to approximate the real value of the rotor resistance giving a base for an adaptive control algorithm which results in a robust and high performance control in any speed range.
	Field Weakening Operation of a Sinusoidal-Field Synchronous Servo Drive with d-q Current Controllers   By K. Veszpremi; I. Schmidt; D. Bakos; K. Vincze	[View]   [Download]
Abstract: In this paper we have examined a permanent magnet sinusoidal synchronous servo machine with current controllers working in d-q (fixed to the rotor) reference frame. We used a simulation program, and examined the relations between the current range and the voltage demand. If the link voltage of the inverter is decreased, above a definite speed, in id and iq current components some oscillation will appear. The characteristics of this oscillation depend only on the parameter set of the servo drive, and the controllers. We gave a reasonable method for decreasing the “q” component of the current to avoid the oscillations in the currents.
	Fuzzy Adaptive Control of an Induction Motor Drive   By L. Romeral; M. R. Chekkouri; E. Aldabas; J. Catala	[View]   [Download]
Abstract: Adaptive control for high-performance drives systems is today an important subject of research. AC drives requiring good position command tracking and load regulation responses are increasingly demanded in industrial applications. The tracking and regulation accuracies should not be affected by parameter uncertainties, unknown load variations or external disturbances. This can only be achieved by an adaptive type control because of the loading conditions, inertias and system parameters are all changing during the motion. Generally the adaptation is attainted by using either the model reference approach or recursive plant parameters identification, but they present complex algorithms and low responses respectively. In this paper is developed and tested a Self-Tuning Adaptive Speed Controller for AC drives with a very low computational algorithm. The authors propose a self-tuning control based on a supervisory fuzzy adaptation. The supervisor continuously monitors the status of the system through the error and its derivative and changes the Ki parameter of an standard PDF controller for adapting it to the plant evolution according to the dynamics of the system. The fuzzy logic adaptive strategy has been readily implemented, with very fast learning features and very good tracking and regulation characteristics. The stability analysis of the developed controller has been also carried out, and experimental results demonstrate the robustness of the suggested algorithm in contending with varying load and torque disturbance.
	Fuzzy-Logic Based State Selector for DTFC of Induction Machine   By M. Zalman; I. Kuric	[View]   [Download]
Abstract: Fuzzy logic is applied as controllers for many industrial applications. The reason of this trend is caused by increasing requirements of the control system properties. This paper discusses the application of fuzzy logic to control induction machines using direct torque and flux control (DTFC). This method of artificial intelligence is used to emulate the state selector and controllers for DTFC. For estimate flux and torque magnitude is used current model based estimator. Computer simulations of the motor and fuzzy system are presented and compared with classical Takahashi’s method of DTFC and Improved Takahashi’s method. For computer simulations are used software Matlab Version 5.3.
	H. Output Feedback Controller Design for AC Motor Control   By D. Fodor; K. Biro; L. Szalay	[View]   [Download]
Abstract: In this paper an H-inf controller is designed for three phase asynchronous motors. The model of the motor was given in its state space representation in the d-q reference. A feedback controller was used which was synthesized by combining a full information controller with an estimator to reach the desired results. A simplified model was used in the design process increasing the modelling noise of the system. There are exogenous inputs considered as disturbances, which are not correlated with the measurement noise. With the designed controller the effects of the disturbances entering the plant and the influence of the measurement noise and modelling errors can be minimized. The desired controller is given by a state space model. The simulation of the system was made with MATLAB/Simulink. The controller is realized as a Simulink embedded S-function, allowing good reference tracking.
	Improved INFORM-measurement sequence and evaluation for sensorless permanent magnet synchronous motor drives   By E. Robeischl; K. Salutt; M. Schroedl	[View]   [Download]
Abstract: For INFORM-based sensorless position estimation with conventional current sensors the current control is interrupted in certain time intervals. During the so called INFORM-measurement, definite voltage space phasors are applied to the machine and the resulting current response is measured. A suitable evaluation of the measured quantities yields the required rotor position. The basic idea of the presented paper is to minimise the INFORM-measurement with respect to its duration and its repetition rate. Combining the improved measurement sequence with a corresponding modified evaluation a high quality position estimation is obtained at significantly reduced current distortion compared to the previous measurement sequence.
	Induction Motor Control with Parallel Speed and Stator Resistance Mras Based Estimation   By S. Vukosavic; D. Reljic; V. Vasic	[View]   [Download]
Abstract: This paper proposes a novel model reference adaptive system (MRAS) for speed controlled induction motor drive without shaft sensor, with integral the adaptation mechanism for the on-line tuning of the stator resistance (Rs). In an intent to accurately estimate the ù at low speeds, without deterioration the drive performance, parallel with the ù estimation the Rs is also estimated to compensate Rs thermal variation. The reference model and adjustable model are interchangeable for parallel ù and Rs estimation. For the stator resistance identification, the two models switch their roles. The dynamics of the ù derivation and the Rs estimation are investigated for a wide range of operating conditions and straight forward design procedure is proposed by hyperstability theory. Extensive computer simulation prove the effectiveness of the proposed solution.
	Industrial Sensorless Permanent Magnet Synchronous Motor Drives based on the INFORM® Method for High Performance Including Standstill   By M. Lambeck; M. Schroedl; U.-H. Rieder; E. Robeischl	[View]   [Download]
Abstract: In the paper, the industrial implementation of the sensorless INFORM method in a commercial permanent magnet synchronous motor (PMSM) drive system is presented. The hard- and software structure of the drive is shown and the used sensorless system (INFORM combined with an EMF model) is described. The implemented starting procedure for overcoming the 180 degrees - ambiguity is given. Measurement results at an industrial INFORM-system are shown.
	Integral Criterion-Based Adaptive PID Angular Speed Control   By S. Bogdan; Z. Kovacic; M. Puncec	[View]   [Download]
Abstract: The paper describes a method of indirect PID controller adaptation by adapting a gain coefficient and a time constant of a lead-lag filter added at the output of the controller. Once calculated, the output of the PID controller is filtered by a lead-lag filter whose gain coefficient and time constant are adapted. Adaptation is carried out by using quantitative relations that link second-order reference model parameters and a corresponding integral criterion. The proposed adaptive PID control scheme has been tested in the angular speed control loop of a permanent magnet synchronous motor (PMSM) drive. The simulation results confirmed its effectiveness in spite of its distinct simplicity.
	Intelligent soft starters for induction motors on the base of fuzzy logic control   By R. Brzesinski; V. Chrisanov	[View]   [Download]
Abstract: The paper describes the conception of an intelligent soft starter for an induction motor (IM) on the base of thyristor direct converters and fuzzy logic control (FLC). The necessary conditions to be realized for soft starting process are reported and general algorithms of thyristor converter control are suggested. It is shown that in accordance with combined control (voltage/frequency control) at the multi step mode of starting under electromagnetic and electromechanical transients the proper choice of thyristor triggering algorithms is a complicated procedure. To overcome that problem the FLC for thyristor soft starter (TSS) is implemented and the system TSS-IM is investigated. The paper consists of three parts: classification and analysis on the base of spiral vector theory; transient phenomena in IM under starting process; optimal starters design with fuzzy logic control.
	Introduction of Stored Energy Variation Factor (SEVF) in Switched Reluctance Motor Drive   By X. D. Xue; S. L. Ho; Y. Lu; K. W. E. Cheng	[View]   [Download]
Abstract: A new term in switched reluctance motor (SRM) drives, namely stored energy variation factor (SEVF), is presented in this study, which is defined as the ratio of stored energy variation to total input energy. SEVF is similar to power factor (PF) in switched reluctance motor drive. The analytical expression of SEVF is derived when switched reluctance motor drive runs under voltage PWM operation. In addition, the computation of SEVF under single-pulse operation is described. The computations and the experiments show that SEVF can indicate not only DC energy changes, but also changes of power factor under both PWM and single-pulse operation. SEVF can provide an insight into the DC energy conversion in switched reluctance motor drives.
	Linear Quadratic Optimal Control of an Electrical Servo Drive System   By F. Ostafi; S. Dumbrava; A. Onea; C. Botan	[View]   [Download]
Abstract: The linear quadratic with finite final time problem for a servo system with a brushless or a d.c. motor is presented. Using some previous results of the authors, a convenient method is indicated; the proposed algorithm allows the simplifying of the optimal control law implementation.
	Modernization of Electrical Transport Systems in Estonia   By M. Lehtla; T. Lehtla; J. Joller; V. Boiko; D. Vinnikov; J. Laugis	[View]   [Download]
Abstract: The paper is based on the results of a long-term modernization project concerning of electrical transport systems in Estonia. Several investigations on traction drives of locomotives, trolley buses and trams have been realized by the Department of Electrical Drives and Power Electronics of Tallinn Technical University in close co-operation with different transport firms. As a result of this work, a new principal solution of traction drive for trams and a new auxiliary power converter were developed and implemented in city traffic.
	Motion Control of a Bogie with Independently Motorised Wheels   By R. Corradi; M. Mauri; F. Mapelli; F. Cheli	[View]   [Download]
Abstract: The new low floor tramcar vehicles present dynamic characteristics completely different to traditional tramcar with solid axels. In order to better the safety (derailment) and the comfort (acoustic and vibrations) and to reduce the wear of track and wheels of these new vehicles the research faces to active and passive mode of steering the bogie similar to the automotive case ([1][2]) and different control strategies. This paper deals with active steering of the bogies of modular low floor vehicles with independently motorised wheels based on a suitable coordination of the wheel controllers. An electromechanical model of the modular vehicles is proposed and a new control strategy is presented.
	Nonlinear Feedback Robot Arm Control   By M. Gautier; P.-Ph. Robet	[View]   [Download]
Abstract: In this paper we discuss the theoretical design of a N axes robot arm dynamic controller, called computed voltage controller, which includes the current dynamics of a synchronous driver (brushless DC motor). The method is implemented on an experimental one axe robot joint. Generally, the advanced control laws of robot manipulators, such as computed torque control, consider the joint drive chain as a constant gain, that is to say the controllers are designed at the 'torque input' level [1][2]. But in the case of high speed motion/force control of robot manipulators the dynamics associated with the actuators can't be neglected [3]. Including the robot actuator dynamics into the robot equations typically makes the latter a system of third order non linear differential equations. A few authors have discussed this problem, but with complicated control law such as Freud’s nonlinear control theory or with the Riccati equation applied to a robot driven with a DC motor [4][5]. Based on the dynamic control technique [6], we propose to include the current dynamics of brushless motor to yield to a global stability of a robot arm. Compared with the computed torque control law which needs the desired joint position, velocity and acceleration, the global computed voltage control law requires the desired joint position, velocity, acceleration and jerk to track. To realize this type of control law, the parameters identification has to be done carefully. A closed loop identification of an inverse model which is linear in relation to the parameters has been performed using least squares techniques and exciting trajectories [7]. These method has been use to get the electrical parameter of the synchronous machine [8] and the mechanical parameter of the robot [9].
	Power Supply Concept of the Longstator Linear Motor of the NBP-Test Track   By A. Pottharst; H. Grotstollen; M. Henke	[View]   [Download]
Abstract: The NBP (Neue Bahntechnik Paderborn) project has been established at the University of Paderborn five years ago and a test track will be used for investigations on railway vehicles (shuttles) driven by linear motors. The linear drive is part of a complex mechatronic system with a modular design. The control structure of this railway system is based on the operation of autonomous shuttles which are fitted with individual power management on board. The power supply of all track sections is decentralized, so reference values have to be sent directly from the shuttles to the local power supply units distributed along the track sections.
	Reduction of Secondary Saliencies for Improved Sensorless Control of Induction Machines using HF Injection   By K. J. Bradley; G. M. Asher; C. Caruana	[View]   [Download]
Abstract: This paper concerns the estimation of the machine rotor flux position using high frequency injection for the sensorless torque control of induction motor drives at zero and low speed. The paper focuses upon the decoupling of saturation induced saliencies by exploiting a magnetic signature of the machine derived using the method of Space Modulation Profiling (SMP). The aim is to reduce the errors in the flux angle estimation and hence to operate the drive in sensorless torque control. An off the shelf 11kW machine is used in which previously reported methods cannot be used without appropriate decoupling.
	Robust control of an induction machine: comparative study of H infinity synthesis and robust pole assignment   By Y. Legorrec; X. Linshi; G. Clerc; J.-M. Retif; C. Duval	[View]   [Download]
Abstract: Our paper deals with the synthesis and the comparison of two robust controllers since embedded applications require fixed parameters. In order to quantify robustness in relation to parameter variations and actuator and measure disturbances, we only consider the most restrictive robustness indicators: the module and delay margins. In a similar way, noise rejection is quantified by sensitivity functions, which represent the influence of noise on the input or the output. The first method is dedicated to H infinity optimization of controllers. The main part of our work deals with the designing of the weighting functions using sensitivity functions (Fig. 1), which ensures the convergence of the optimization process and the realization of the different margins. The controller is simplified by the balanced model reduction and sampled by the Tustin transformation, which keeps the H infinity norm. The second method deals with polynomial RST corrector, which is synthesized by robust pole assignment using a stochastic genetic algorithm and Fuzzy logic rules (Fig. 2). It takes into account constraints of robustness while satisfying the requirements of performances. Our new approach deals with the synthesis of a robust corrector, which satisfies the same set of conditions on output disturbance rejection and stability robustness on errors of modeling. The two methods are compared with the same schedule, which define the noise rejection and robustness objectives. They are applied in order to synthesize the current correctors on a vector field oriented control of an induction machine.
	Robust Fuzzy-Sliding Mode Position Control for Motor Drives operating with Variable Loads   By J. Arellano-Padilla; G. M. Asher; M. Sumner	[View]   [Download]
Abstract: This paper reviews and develops a new approach to Fuzzy-Sliding Mode Control (FSMC) for the robust position control of practical motor drive systems. Robustness is achieved through the definition of a real time reference transient trajectory for the switching function of the Sliding Mode Control (SMC); this trajectory error is the input for a fuzzy interpolation between control laws corresponding to the boundary values of the plant parameters. The paper reviews the background of the approach and develops a design procedure for the fuzzy interpolation to yield robust performance for large range of parameter variations. Simulated results are presented considering the noise constraints presented in real systems. It is well known that the transducer quality and measurement noise ultimately limit the close loop dynamic, this paper considers this aspect of real systems and develops a simple method to set the controller gain in order to get a robust performance during transients and low system noise during steady state.
	Self-learning Impedance Control of the Robot Systems   By F. Palis; V. Rusin	[View]   [Download]
Abstract: This paper presents an efficient impedance control scheme for legs of walking machines interacting with an uncertain environment and proposes an impact control based on neural system. The proposed method combines the technique of the indirect MRAC (Model Reference Adaptive Control) with the properties of self-learning neural nets. Present research is focused on the optimisation of motion of mechanical systems with constraints on the contact with the environment in order to cover given contact quality requirements (minimal tendency to oscillations, contact stability, damping, contact force limitation).
	Sensorless Control of Double Fed Machine for Wind Power Generators   By E. Bogalecka; Z. Krzeminski	[View]   [Download]
Abstract: Energy conversion in wind power generators takes place with speed variation within a limited range. In such applications a double fed machine (DFM) becomes very interesting solution in comparison with synchronous machine and squirrel cage induction machine [1]. The DFM working as a generator parallel to the grid should be a controlled source of active and reactive power. High quality of electrical energy production requires decoupled control of both powers. In addition a variable torque produced by the wind should not influence the active power of generator. The reference value of reactive power is often set to zero. Requirements may be fulfilled by proper control system choice. Different schemes of the DFM control system can be proposed. In the paper two control method of the DFM with different principle of the control system synthesis and a different principle of the VSI control are presented. Both systems are sensorless.. In the first proposal a new model of the machine, called multiscalar model developed by Krzemiñski [7] is used for control system synthesis. Nonlinear feedback, based on this model transforms the system into two independent linear subsystems: mechanical and electromagnetic. The inverter is controlled by a voltage PWM algorithm. A rotor position is estimated. The second presented control system is simpler. Synthesis of the control system is based on a vector control theory. An additional angle controller is used to synchronise rotor with the stator [3], instead of the rotor position sensor. The inverter is current controlled. To obtain a constant switching frequency of the inverter a predictive current controller is used [8]. Features of the machine control system depend on the system structure, controllers settings and on the method of the inverter output voltage control. Features of both systems are simulation investigated and compared.
	Sensorless torque control of permanent magnet synchronous machines over the whole operation range   By S. Beineke; J. Kiel; A. Bünte	[View]   [Download]
Abstract: The subject of this paper is a method for sensorless torque control of permanent magnet synchronous motors (PMSM), which is suitable for low speed including zero, medium and rated speed. The estimation of the rotor position at low speed is based on saturation effects, for medium and high speed an open-loop observer has been chosen. By combining both methods it becomes possible to cover the whole speed range. This procedure is completed by a suitable initialisation, also based on saturation effects, and a method for switching between both techniques.
	Single Controller Current-Sensorless Speed Control of PMSM Using Inverse Drive Model   By H. Sammoud; W. Schumacher	[View]   [Download]
Abstract: This paper presents a new structure for the speed control of surface mounted permanent magnet synchronous motors (PMSM) based on the inverse drive model (IDM). Compared to the classical cascade control structure, the IDM doesn’t require any current sensor because the current is not controlled. The inverter voltages are directly computed from the desired torque. Thus, contrary to the cascade structure, there is no limitation of the dynamic performance due to the delay of the inverter. The inverter voltage limits are considered in the IDM in order to avoid deviations of the estimated torque from its actual value. This can be achieved by a feedback of the DC-link voltage, which limits the derivative of the quadrature current. Above the base speed range the IDM operates even without supplementary non linear block or voltage controller for field weakening. It can be shown that, compared to the cascade control, the IDM has a higher dynamic over the whole speed range. In addition to its stability and the insensitivity to position error, the IDM operates at better efficiency than the cascade control when the motor is controlled above the base speed range. This is due to the fact that no voltage reserve is required at steady state. The amplitude of the voltage space vector is set to its maximum and torque changes are performed by phase shifts. It can be also proven that the proposed structure guaranties safety against accidental demagnetising of the magnets in the rotor.
	Sliding Mode Technique for AC Drive   By S. Ryvkin	[View]   [Download]
Abstract: This paper presents the different possibilities of the using sliding mode technique for design of control part of AC electric drive. It's shown that many different named control systems are based on the sliding mode. The main attention is paid to explain the well-known merits and demerits of such system. The first part of article is devoted to the design of the sliding mode control in the rotating reference frame and realisation of it with the using of the outputs voltages of the voltage source inverter (VSI) or matrix converter. The using of VSI as current source inverter in the drive is possible because the are sliding mode current control. In the second part is discussed the sliding mode with hysteresis, including application of the special hysteresis for providing a constant switching frequency of the VSI switches and minimum switching loss.
	Speed And Power Of Train Control System   By F. Bozas; V. Radulescu; S. Gheorghe; A. Dascalu; I. Strainescu; D. Braslasu; E. Tudor	[View]   [Download]
Abstract: The paper will present the speed control system developed to control a traction equipment consisting in more than one drive, as the two-motored tramcar, the double-unit metro or the automotive coach for railway are. The system contains hierarchical processor controllers for speed and torque. Speed regulators are based on velocity measurements of the axles. The diagnose tasks are performed locally by every controller and the central diagnose task can operate the data with high resolution.
	The Analysis of Direct Torque Control Induction Drive Microtransients   By E. I. Barats; I. Y. Braslavsky; Z. S. Ishmatov; A. V. Kostylev; M. A. Averyanov	[View]   [Download]
Abstract: This article is devoted to the analysis of the transients arising in induction motor fed by a voltage inverter in direct torque control system. The analysis of flux and torque ripple in various operating modes is based on system dynamics research with step action of a voltage vector. The problem of increased ripple at high speed is described. A variant of voltage vector switching table correction is offered. The approach proposed decreases the ripple level. Simulation results are given.
	The Influence of the Rotor Resistance Changes on the Global Stability of Indirect Field-Oriented Drive Systems   By M. Dubowski; A. Andrzejewski	[View]   [Download]
Abstract: In this paper the global stability analysis of the IFOC class systems, with regard to rotor resistance changes, will be presented. The analysis will be realized with use of the direct Lyapunov’s method. In the paper such a range of the type PI speed regulator parameter values has been evaluated in which the system’s resistance to the rotor resistance changes is the largest.
	Two Reliable Methods for Estimating the Mechanical Parameters of a Rotating Three-Inertia System   By P. Mutschler; I. Muller	[View]   [Download]
Abstract: In this contribution, two methods for the estimation of the mechanical parameters of a rotating threeinertia system are presented. The estimation methods have been tested at two different experimental set-ups. Each experimental set-up consists of a motor, which is connected to a load machine by a coupling and a shaft. The set-ups have to be considered at least as weakly damped three-inertia systems. The first presented estimation method is the classic Least-Squares estimation with ARMAXmodel (Auto-Regression with Moving Average and eXtra inputs) with high order. With this method, the resonant frequencies are extracted and from them and from the total inertia the three inertias and the two torsional stiffnesses are calculated. The second method is a more graphical one. From the FFT of the system response the maximum values and the minimum values are searched for. The dominant frequencies are found with suitable criterions. The results, which are achieved with both methods, are accurate enough for designing a state controller, which damps both resonances actively. The classic estimation method can be fitted to other systems, whereas the graphical method takes much less calculation time and is less sensitive to disturbance.
	Vector Control Systems of Tandem Converter Fed Asynchronous Motor for Rapid Prototyping with Module Library   By R. Munteanu; J. Vasarhelyi; C. Szabo; M. Imecs; I. I. Incze	[View]   [Download]
Abstract: The paper deals with the reconfiguration computing method applied for the vector control system of the asynchronous motor supplied from the failed and non-failed tandem frequency converter. The tandem converter has a hybrid topology consisting of two parallel-connected DC-link converters of different type and different power. It is containing a pulse-amplitude-modulated Current-Source Inverter (CSI) of large power and another pulse-width-modulated Voltage-Source Inverter (VSI) of reduced power. The proposed synchronization ensures the proper distribution of motor currents between the two component inverters. The tandem-converter-fed drive is also able to operate if the VSI is out of order, but the control strategy needs modification. In both cases the vector control structure is oriented according to the resultant rotor flux. A modular structure of the control systems allows the easy changing and rapid prototyping of the schemes. The control blocks for the described drive systems are implemented using Xilinx configurable logic cells (FPGA) and they are parts of a module library. The created library modules were compared with the corresponding Simulink modules. The comparison was made from point of view of the simulation. The module library quantisation errors were also studied for each implemented module. MATLAB-Simulink simulations are presented of the whole drive system concerning the reconfiguration of the control structure from tandem-converter-fed asynchronous motor to the CSI-fed one.
	Vector Sliding Mode Control of Sinusoidal-Field Synchronous Servo Drive   By K. Vincze; K. Veszpremi; I. Schmidt	[View]   [Download]
Abstract: Permanent magnet synchronous servo drive with sinusoidal field is examined. The proposed control method is the sliding mode control, implementing the speed control, the current vector control, limitations and field weakening. The necessary sliding errors are derived. Different evaluation criteria are investigated by simulation and a new one is proposed. The combined vector sliding mode control, where the intervention depends on the magnitude of the sliding errors is better, than the traditional vector bang-bang control. The robustness of the bang-bang control is retained, the switching number and the steady state chattering are decreased.