Stepping motors are often used for low-power open-loop positioning. In conventional stepping motor drives, a step rate or speed is imposed. To avoid step loss in open-loop, most stepping motors are driven at maximum current resulting in a... more
Stepping motors are often used for low-power open-loop positioning. In conventional stepping motor drives, a step rate or speed is imposed. To avoid step loss in open-loop, most stepping motors are driven at maximum current resulting in a poor energy efficiency. However, when position feedback is available, the drive current can be optimised. A position sensor adds costs and complexity to the system. Therefore, rotor position estimators are developed, often referred to as sensorless controllers. A drawback in some of these methods is the requirement of information on the mechanical load which is usually not available or varies over time. In this study, an alternative estimator is proposed, based on the load angle between the current excitation vector and the instantaneous rotor flux position. This load angle reflects the capability of the system to follow the speed setpoint and gives an indication of the robustness to torque disturbances. Therefore the load angle estimation is inter...
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In this paper an analytic method to study space-harmonic effects and to map the influences of geometric design parameters on the line-start permanent-magnet synchronous machine (LSPMSM) dynamic performance (start-up and other transients)... more
In this paper an analytic method to study space-harmonic effects and to map the influences of geometric design parameters on the line-start permanent-magnet synchronous machine (LSPMSM) dynamic performance (start-up and other transients) is presented, based on Winding Function Theory (WFT). The mutual inductances between a rotor, containing barriers and iron bridges near the magnets, and a stator with concentric windings are computed. As the iron bridges near the magnets are in saturation due to the high magnetic field of the magnets, the assumption is made to represent the rotor in different parts. Each part has a high permeability, and is separated by a layer of low permeable material, i.e. the magnets, the saturated bridges and the barriers. The magnetic coupling is described, and the different computation methods to obtain mutual inductance values are given. Using finite element methods (FEM) the WFT-resulting inductances are verified.
To reach energy efficiency goals the demand to high efficient motors, among which Permanent Magnet Motors, is increasing. In order to analyze and to predict the performance, equations based on equivalent circuits are generated. Lumped... more
To reach energy efficiency goals the demand to high efficient motors, among which Permanent Magnet Motors, is increasing. In order to analyze and to predict the performance, equations based on equivalent circuits are generated. Lumped parameters have to be estimated and for simplicity often coarse assumptions are made, affecting the accuracy of the model. In this paper flux-linkage and inductance variations in (LineStart) Interior Permanent-Magnet Synchronous Machines are discussed. Attention is given to the influence of the behavior of the ferromagnetic material caused by load angle and current variations and more specific to the geometric design parameters, in particular to the magnetic conductance of the bridges. Finite Element Method is used for parameter estimations and detailed magnetic field research.
Nowadays numerous techniques to model the behaviour of electrical drives are discussed in the literature. In many cases a linear magnetic network is proposed. This paper proposes a large-signal simulation model of an induction machine... more
Nowadays numerous techniques to model the behaviour of electrical drives are discussed in the literature. In many cases a linear magnetic network is proposed. This paper proposes a large-signal simulation model of an induction machine that takes into account the magnetizing-flux saturation. The model is given as a state-space model with nonlinear feedback and is implemented in Matlab/Simulinkreg. The advantages of the proposed model include versatility and ease of use. Simulation results from both this model and a linear flux model show the differences between the models. Advantages and disadvantages of the proposed simulation model are discussed and the area of application is defined. The usefulness of the model to study large transients and the dynamic behaviour of induction machines in control loops is discussed. For this purpose the proposed model is used to simulate induction machines in drives, such as direct torque control and indirect field orientation.
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In this paper a nonlinear model for AC machines is proposed that takes into account the magnetic saturation and magnetic interaction between both orthogonal magnetic axes. Furthermore, the model includes the presence of air-gap flux... more
In this paper a nonlinear model for AC machines is proposed that takes into account the magnetic saturation and magnetic interaction between both orthogonal magnetic axes. Furthermore, the model includes the presence of air-gap flux harmonic components caused by magnetic saturation and multiple-pole spatial saliencies. Such a model is used to describe in a uniform way motion-state estimators for AC drives that are recently discussed in the literature. Emphasis is given to salient-pole synchronous machines with a rotor field winding or a permanent-magnet excitation (PMSM)
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The use of embedded Runge–Kutta methods for the time-domain simulation of a dynamic finite element model of a switched reluctance motor is discussed, along with the features of embedded Runge–Kutta methods for the numerical solution of... more
The use of embedded Runge–Kutta methods for the time-domain simulation of a dynamic finite element model of a switched reluctance motor is discussed, along with the features of embedded Runge–Kutta methods for the numerical solution of this model. It is shown that step size control and interpolator polynomials can be used to take accurately into account the discrete effects of current control and a pulse width modulated supply on the drive dynamics.
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This paper discusses fundamental equations which can be used in high-frequency signal based position estimators for synchronous machines. For this purpose, a small signal dynamic flux model is presented that takes into account the... more
This paper discusses fundamental equations which can be used in high-frequency signal based position estimators for synchronous machines. For this purpose, a small signal dynamic flux model is presented that takes into account the nonlinear magnetic condition and the magnetic interaction between the two orthogonal magnetic axes. The derivation of this model is based on the relationship between flux and coenergy. The model is given in a complex notation and is used to discuss most high-frequency signal based position estimators that have appeared in the literature. By using the finite element method, the coenergy of a given salient-pole synchronous machine is calculated and from it an estimation is made of the parameters in the proposed model. Through experiments it is shown that, by using the relationship between magnetizing current and flux as modelled in this paper, the nonlinear behaviour of the synchronous machine is quite accurately estimated. Furthermore, the new model is comp...
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... EELAB), Department of Electrical Energy, Systems and Automation (EESA), Ghent University, Ghent, Belgium, and René K. Boel SYSTeMS, Department of ... By using the forward rectangular rule (Franklin et al., 1998), the relationship, in... more
... EELAB), Department of Electrical Energy, Systems and Automation (EESA), Ghent University, Ghent, Belgium, and René K. Boel SYSTeMS, Department of ... By using the forward rectangular rule (Franklin et al., 1998), the relationship, in a discrete time, between stator current and ...
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A new space vector torque control strategy is developed for switched reluctance machines. The method is based on an existing space vector control strategy, which yields an explicit expression for the phase currents realizing a desired... more
A new space vector torque control strategy is developed for switched reluctance machines. The method is based on an existing space vector control strategy, which yields an explicit expression for the phase currents realizing a desired torque at a given rotor position. With the improved strategy, a higher torque-current ratio is achieved. A new approach based on space vector trajectories is given to determine the commutation between phases. For a constant reference torque, the improved method guarantees continuous reference currents. Therefore, smooth torque control is possible for a wide speed range and servo-grade performance can be achieved.
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Recent research on stepping motors concerns intelligent motion control algorithms such as sensorless vector control. Sensorless control is commonly based on a motor model. For stepping motors, this model is highly nonlinear, resulting in... more
Recent research on stepping motors concerns intelligent motion control algorithms such as sensorless vector control. Sensorless control is commonly based on a motor model. For stepping motors, this model is highly nonlinear, resulting in a high computational cost. When the motor is controlled by a vector-controlled algorithm, the position dependence of certain model parameters can be eliminated. If saturation and reluctance effects are neglected, the motor model can be transformed into a linear model. In this paper, the linear model is verified by simulations and measurements. A profound sensitivity analysis proves the robustness of the model. Due to the hybrid motor construction reluctance effects occur. These effects are also measured and discussed.
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This paper discusses fundamental equations used in high-frequency signal based interior permanent-magnet synchronous motor (IPMSM) position estimators. For this purpose, an IPMSM model is presented that takes into account the nonlinear... more
This paper discusses fundamental equations used in high-frequency signal based interior permanent-magnet synchronous motor (IPMSM) position estimators. For this purpose, an IPMSM model is presented that takes into account the nonlinear magnetic condition, the magnetic interaction between the two orthogonal magnetic axes and the multiple saliencies. Using the novel equations, some recently proposed motion-state estimators are described. Simulation results reveal the position estimation error caused by estimators that neglect the presence of multiple saliencies or that consider the magnetizing current in the d-axis only.
Stepping motors are used in numerous applications because of their low manufacturing cost and simple speed control. It is well known that their energetic efficiency is low but actual values are typically not available. In this paper the... more
Stepping motors are used in numerous applications because of their low manufacturing cost and simple speed control. It is well known that their energetic efficiency is low but actual values are typically not available. In this paper the influence of the control ...
... Record Details. Record ID, 345574. Record Type, conference. Author, Frederik De Belie [801001652895] - Ghent University Frederik.DeBelie@UGent.be; Thomas Vyncke [801002034633] - Ghent University Thomas.Vyncke@UGent.be; ...
Page 1. Embedded Runge-Kutta Methods for the Numerical Solution of an Integrated Model In-cluding Converter, Nonlinear Inductance and Current Control Loop Kristof R. Geldhof, Thomas J. Vyncke, Frederik MLL De Belie, Lieven Vandevelde and... more
Page 1. Embedded Runge-Kutta Methods for the Numerical Solution of an Integrated Model In-cluding Converter, Nonlinear Inductance and Current Control Loop Kristof R. Geldhof, Thomas J. Vyncke, Frederik MLL De Belie, Lieven Vandevelde and Jan AA Melkebeek ...
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ABSTRACT Stepping motors are used in numerous applications because of their low manufacturing cost and simple open-loop position control capabilities. It is well known that their energy efficiency is low, although the actual efficiency... more
ABSTRACT Stepping motors are used in numerous applications because of their low manufacturing cost and simple open-loop position control capabilities. It is well known that their energy efficiency is low, although the actual efficiency values are generally not available. Moreover, the bulk of the stepping motors are driven in a non-optimal way, e.g., in an open loop with a maximum current to avoid step loss and, thus, with low efficiency. In this article, the impact of the control algorithm on the efficiency of the motor is analyzed, measured, and discussed. The basic open-loop full-, half-, and microstepping algorithms are considered together with a more advanced vector control algorithm. For each algorithm, the torque/current optimization is discussed.