Article
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Electromagnetic contactors have a non-linear behavior due to the magnetic force. This paper develops a robust and low time-consuming parametric model to describe the dynamic behavior of both AC and DC contactors. The proposed model solves simultaneously the mechanic, electric and magnetic coupled differential equations that govern its dynamic response. This model takes into account the fringing flux, an effect that greatly influences the dynamic behavior. In case of AC contactors, the model deals with the shading rings. First, the electric and magnetic equations of an AC contactor – which are more complex due to the effect of the shading rings – are introduced. After that, by simplifying this set of equations, the ones of a DC contactor are derived. Conversely, mechanical equations are the same for both, AC and DC powered contactors. Data from simulations carried out by applying the presented parametric model are compared with experimental data, being demonstrated its accuracy and effectiveness.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

... The design and manufacture of electromechanical devices is a highly specialized process subject to many requirements due to the interconnected nature of the electrical, mechanical and thermal designs. Contactors are electromechanical switches employed in applications that require processes of electric circuit "making and breaking", such as starter motors, electric vehicles, heaters, and lighting applications [1]. In the past, the design and development of electromechanical contactors has been based on extremely simple analytic models, supplemented by experience and intuition. ...
... In the definition of the lumped elements, each region where the magnetic flux density B is more or less uniform is represented by an element of a given magnetic reluctance. The relationship between the variables is ,    F (1) where F is the magnetomotive force,  is the magnetic reluctance, and  is the magnetic flux. ...
Article
Full-text available
The paper addresses complementary approaches to the calculation of electromagnetic parameters of an industrial alternating current (AC) contactor rated for 220 volts and 60 hertz. The methods of analysis include conventional electric circuits derived from measurements of terminal characteristics. The duality between interlinked electric and magnetic circuits is employed to calculate the contactor's magnetizing reactance during a locked closing maneuver and during the closed-core configuration. The parameters obtained from the circuit analyses are compared to the more precise estimates of finite element analyses. Special attention is given to the subtle differences of circuit properties applied to the conductive regions containing driving currents as well as to regions where current is actually induced due to time variation of the magnetic flux. Attempt is made to facilitate the understanding of the physical phenomena related to the presence of eddy currents in the shading rings.
... Indeed, contactors are one of the most common discrete electrical components in the current industrial power systems. They are used in such diverse industry applications as rectifiers, motor drives, and uninterruptible power supply systems [41]. In modern machinery applications, such as packaging, pallesting or conveying, it would not be considered unusual to switch three-phase electric motors equipped with ACcontactors each second [42]. ...
Article
Full-text available
This paper presents a study of industry equipment electrical responses under voltage dips with different magnitude, duration and point-on-wave initiation. The analysis provides electrical sensitive curves for safe and reliable operation based on experimental tests performed over real AC-contactors, ground fault relays, variable speed drives, industrial computers and lighting loads. The presence of a relevant scatter-band where the sensitivity of some equipments in the presence voltage dips responds in a stochastic manner is analysed. The effect of the working temperature of the device is studied as well. A detailed description of the testing procedure is provided, proposing additional voltage dip parameters to characterize the equipment sensitivity in detail. In this way, existing standards and previously published contributions are reviewed and compared with the obtained results. The obtained results are useful for OEMs, Utilities as well as Uninterruptible Power Supply Manufacturers; where a more precise counting of equipment failures due to voltage dips is essential for an economic and technical assessment of power quality.
... The solubility of nitrogen mainly depended upon the composition of alloy and partial pressure of nitrogen. For instance, the addition of manganese, chromium, molybdenum and vanadium increased the solubility of nitrogen whereas the addition of carbon, silicon and copper decreased it [1,2]. The excellent nitrogen solubility was obtained by reducing the melting temperature and by increasing the nitrogen pressure. ...
Article
Full-text available
In the present work the effect of nitrogen on WC9 alloy at various weight percentages was analyzed and tested for their microstructural and mechanical properties. The nitrogen was added at 0.05, 0.10, 0.15, 0.20 and 0.25 wt. % in the solid form as nitrided ferrochrome to WC9 alloy. The samples were heat treated by solution annealing process at a temperature of 1100°C for 5 hours to improve the austenitic formation. Microstructures and mechanical properties such as tensile strength, yield strength, hardness, % elongation and % reduction of WC9-N alloy were examined. It was observed that increasing nitrogen wt. % increases the mechanical properties. The obtained mechanical properties were compared with base WC9 and C12A grade steel, where it was found to be replacement for C12A grade steel at its composition at lower end. The material cost analysis for WC9-N and C12A grade steel was done and both were compared.
... This effect amid conclusion is the starting point of the contact skip, otherwise called babble. It is an undesirable marvel, which brings about a re-opening of the contacts, creating the ghost of an electric circular segment until the contact makes unquestionably [2]. The curve can bring about extreme contact disintegration, and consequently the electrical life and unwavering quality of the contacts are drastically decreased [3,4]. ...
Article
Full-text available
An electrical contractor is one which plays significant role in day todays life in industries as well as in home appliances. In current scenario the materials for conducting purpose has an overwhelming research capability. Now a day the silver based electrical contact composite material have provided the potential applications in aerospace and automobile industries. Among silver based contact material the silver cadmium oxide and silver tin oxide plays a vital role in fabrication of electrical contactors. In this research an attempt has been made to study the influence of adding Aluminum with silver based electrical contact composite materials by two different processing routes namely stir-casting and powder metallurgy. Silver and aluminum matrix plays a virtual role in composite world owing to their highest conductivity. Optimum parameters were identified for attaining the maximum properties such as conductivity, hardness, density, and porosity of composition. By this better conducting property and mechanical property of the electrical contact can be improved by this system. Thus a screening test has be conducted with addition of Al with silver tin oxide compositions hence this paper aims to process the aluminum - silver based electrical contact materials by stir casting processing and powder metallurgy route and compare the results obtained.
... By interruption of the coil control circuit, the mechanical contact carrier returns to the starting position. It can control various power loads, primarily motors, electric vehicles, geysers, and lights [1]. Contactors should have high reliability in order to reliably control the circuit. ...
Article
Full-text available
In this paper, a new model for estimating the remaining electrical life of the AC contactor is proposed. The model involves an equation that use the rated and operational parameters, material properties and geometries to estimate electrical health of contactor. The variation in the contact resistance as a function of time is found varying in accordance with the remaining electrical life of the contactor. This characteristic parameter along with the data regarding the quantity of material lost at the contact surface has been fed as the sample data for the machine learning model. The sample data is carefully chosen from the contactors operating at different environmental conditions and utilization categories to include wide range of data. Using the collected data from contactors operating in varied environments and utilization categories a Stochastic Gradient Descent Classifier model is generated and used to estimate the remaining electrical life.
Article
A fully coupled simulation framework is developed to predict the dynamic characteristics of the permanent magnet (PM) contactors. Dynamic inductance, magnetic field distribution, and mechanical motion are solved by coupling the electric, magnetic, and mechanical governing equations. The equations are developed in the weak forms and the Weak Form Partial Differential Equation module of Comsol Multiphysics is employed to solve the equations. Influence of PM is taken into account by considering the remanent flux as a static potential. The electromagnetic variables and mechanical variables can be solved in the same discrete time period, which gives much higher calculation efficiency than the existing method. The simulation results show that the framework can predict the changing of the inductance, closing displacement, and excitation current in the time domain. Comparative experiments have been conducted to verify the simulations. Physical measurements show that the dynamic closing process of the contactor can be captured by the model with good precisions.
Article
This paper analyzes the response of AC-Contactors connected to different electrical loads under voltage dips and supply interruptions. A wide range of magnitudes, durations and point-on-wave initiation values are considered for generating the power quality disturbances. For the first time, three types of electrical loads are used to evaluate the AC-Contactor sensitivity under most common power quality disturbances. For this purpose, over 40,000 tests are carried out on AC electromechanical contactors, contributing to reduce the uncertainties of their electrical response outlined in the specific literature. Voltage-versus-time curves of contactors with similar technical specifications, but provided by different manufacturers, are included in the paper. In this way, the behavior of contactors dealing with real situations located in industrial environments is analyzed in detail. The results present a valuable interest for commercial, industrial, utility and OEM sectors, where this kind of switching equipment is widely used in a varying power factor scenario.
Article
Modelling of a real system using different approaches is wide spread in the research and academic communities. There are many studies in literature that treats different ways of simulating systems more or less complex. In this paper, we developed a different approach for modelling a separate excitation DC motor. The proposed article is focused on finding a suitable model that represents the dynamic regime of such motors. Our approach uses an electronic implementation of the mathematical model of the DC motor. A special attention was given to the experimental determination of the mechanical parameters. By this approach the beneficiaries of this system, which will be engineering students, can have a better understanding on how the electronic circuits could be used to simulate a real system. Also our approach could serve for implementing remote laboratories for systems modelling-simulation for electrical engineering studies.
Article
Magnetic actuators are the key components of electric breakers and contactors. An integrated modeling framework has been developed to increase the simulation efficiency of the magnetic contactor. The air is meshed with the moving mesh method in the time domain that the electromagnetic governing equation can be coupled with the mechanical dynamic governing equation. The electromagnetic variables and the mechanical variables can be solved in the same time period for the dynamic response of the actuator. An intelligent ac contactor has been taken as the example to verify the simulation results. The applied voltage chopped with PWM signal is taken as the drive source. Simulation results show that the electromagnetic variables and the mechanical variables can be solved in an integrated framework and the simulation efficiency can be increased. Comparisons of simulations and experiments show that the dynamic response of the magnetic actuator can be properly predicted by the proposed method.
Article
A novel method is developed to calculate the 3D magnetic force based on PDE weak form equations. The matrix governing equation is obtained by transforming the Maxwell magnetic equation to the weak form, which is implemented with weighted residuals. The steady state response and the dynamic response of the magnetic circuit are studied based on the discrete matric equation. The 3D magnetic force corresponding to different exciting current and air gaps are studied by using Maxwell stress tensor. The dynamic response of magnetic force is analyzed by using step response. The influences of the permeabilities and conductivities on the flux density and the magnetic force are studied as well. Simulation results show that the transient peak value of flux density can be reduced by decreasing the conductivity of the electric core. The steady state value of the magnetic force can be enhanced by increasing the permeability. The energy consumptions of the magnetic system are studied. It is found that the main loss of the energy comes from the airgap. The peak value of the loss ratio due to this proportion can be achieved to 90%.
Conference Paper
The paper presents model based analysis and experimental verification of a half-bridge resonant LLC converter for suppling power to the electromagnetic driving mechanism of an electromagnetic contactor. In the proposed application the convertor - powered either by AC or DC voltage - supplies the coil of the contactor with DC voltage. Analytical and experimental results presented, show several important advantages of the proposed topology: versatility in terms of input voltages – both AC and DC are accepted; stability over wide voltage range; omission of overvoltages – common to electromagnetic systems; reduced power consumption.
Article
Electrical life is an important performance indicator of ac contactor, and it is influenced by various factors, among which the most important one is arc erosion caused by arc current. This paper proposes a general contact erosion model based on arcing phase angle to simulate the electrical life distribution characteristics of ac contactor under random breaking operations. For the same type of ac contactor, different individuals have different electrical life due to the manufacturing dispersion, so the normal distribution is utilized to simulate the manufacturing dispersion under $3\sigma $ standard. The simulation results show that the electrical life distribution is closely related to the manufacturing dispersion degree. When the dispersion degree of manufacturing processes is relatively low, the electrical life obeys three-parameter Weibull distribution. Otherwise, the electrical life of contactors obeys normal distribution. Finally, the electrical life test is performed, and the test results are consistent with the theoretical analysis results. The abovementioned conclusion provides theoretical foundation for the reliability evaluation and experimental study of ac contactor.
Article
The electrical performance of ac contactor degrades under electric load stress, and the degradation data contains the information concerning the residual electrical life (REL). This paper proposes an on-line reliability evaluation method that relates contact erosion loss (CEL) to electric load stress, performance degradation process and electrical life prediction. Firstly, the degradation variable of Normal distribution is constructed by segmenting accumulation of CEL, and a degradation model based on Wiener process is established. With the knowledge of the first accumulation of CEL beyond failure threshold, the probability density function (PDF) of REL for ac contactor is presented, and point estimation value and interval estimation value of REL are calculated. Secondly, a simulation electrical life test is conducted by using Monte-Carlo method, and results show that the electrical performance degradation model and prediction method of REL raised in this paper are effective. Finally, CELs weighed in the electrical life test are applied in the prediction process of REL of ac contactor and the prediction error is proved acceptable in practical application. Compared with the neural network based methods, the proposed method provides an intuitive and simple mathematical model with clear physical interpretations.
Article
This paper presents the results obtained from the fiber Bragg grating (FBG) sensors installed on the fixed magnetic core of an electromagnetic AC contactor for temperature and dynamic strain measurements. Using the results analysis, it is possible to apply the sensor system as a preventive maintenance tool, since the deformation experienced is proportional to the electromagnetic force in the contactor. The temperature variation is 76°C and reaches thermal stability at t = 160 minutes on the contactor magnetic core. For the dynamic strain sensing four measurements were carried out with the contactor: intact, with voltage sag, with an air gap obstacle and without shading ring. The electromagnetic force has a fundamental frequency of 120 Hz, which is twice the frequency of the main supply power for the intact and with voltage sag contactor. This fundamental frequency is obtained by using a Fast Fourier Transform (FFT) technique of the steady-state dynamic strain measured wavelength. For the contactor with air gap obstacle and without a shading ring, the FBG wavelength variation is very noisy and the electromagnetic force is not sinusoidal.
Article
Contact bounce is a common phenomenon in the closing process of the electromagnetic relay under capacitive loads. The investigations on the contact characteristics are mainly conducted by experimental methods. However, the experimental method is extremely complicated and time-consuming in structural design, and it cannot clearly reveal the mechanism of contact bounce. Therefore, a new theoretical model is proposed to investigate the dynamic characteristics of the electromagnetic relay under capacitive loads. The model allows for simulating dynamic process and collecting bounce parameters in a simple and effective way compared with conventional simulation and experimental methods. The physical mechanism of contact bounce for the electromagnetic relay is presented. The nonlinear contact force between the fixed and moving contacts is evaluated according to the Kelvin-Voigt viscoelastic contact model. The equations of motion considering the coupling of electromagnetic and mechanical fields are established. The theoretical results obtained in this study are validated by comparison with experimental data. The influences of the structural parameters, coil current, surge current and contact resistance on the contact bounce are analyzed. The numerical results well demonstrate that the contact bounce can be effectively weakened by adjusting the parameters of contact spring and the mass of the moving contact.
Article
Electromagnetic (EM) relay is a commonly used electronic control component, which is extremely sensitive to magnetic field. With the increasing magnetic field around tokamak devices, the reliable operation of EM relay is greatly threatened. Therefore, it is necessary to study the failure mechanism of EM relay under disturbing magnetic field. In this paper, a fully coupled analysis model of EM relay, including electric circuit, magnetic field and mechanical motion, is established. Taking plunger-type DC EM relay as an example, the influence of disturbing magnetic field of EM relay is studied. The relationship between the disturbing magnetic field and the action time, holding force, and some other parameters of the relay is given. Moreover, the failure magnetic field threshold is obtained. An efficient method to suppress the impact of disturbing magnetic field on the relay is proposed. The work presented in this paper has a great significance to improve the reliability of EM relay in the disturbing magnetic field and ensure the stability of tokamak devices.
Article
Medium voltage direct current (MVDC) grids are proposed as a solution for future distribution systems providing advantages of lower transmission losses and high controllability. Protection of a DC grid is more challenging than AC systems due to fast fault propagation and high peak currents as well as lack of current zero crossing. Until now, proposed hybrid DC circuit breakers have been based on the power electronic components and considerably more expensive than AC circuit breakers. In case when DC circuit breakers are applied at each individual feeder, the cost of the MVDC grid increases significantly. In this paper, a multi-feeder protection system is proposed that utilizes the main power electronic part of the circuit breaker for several feeders' protection. The proposed solution allows the reduction of the protection system costs maintaining fast fault clearing capability provided by hybrid DC circuit breakers. Design evaluation of the protection system components is described in detail. Proposed multi-feeder protection solution is potentially capable to be used with any hybrid circuit breaker topology.
Article
Full-text available
The undesirable phenomenon of the contact bounce causes severe erosion of the contacts and, as a consequence, their electrical life and reliability are greatly reduced. On the other hand, the bounce of the armature can provoke re-opening of the contacts, even when they have already been closed. This paper deals with the elimination of the bounce in both contacts and armature of a commercial dc core contactor. This is achieved by means of a current closed-loop controller, which only uses as input the current and voltage of the contactor's magnetizing coil. The logic control has been implemented in a low cost microcontroller. Moreover, the board control can be fed by either dc or ac, and either in 50 Hz or 60 Hz so as to extend its applicability. A set of data is obtained from the measurement of the position and velocity of the movable parts for different operating voltages, and the dynamic behavior of the contactor is discussed.
Article
Full-text available
A new displacement profile control strategy based on pulse-width-modulation (PWM) for improving the dynamic characteristics and reducing the contact bounce of permanent magnet (PM) contactor during the making process is reported. Sensorless method of real time displacement signal detection is realized using magnetic circuit model (MCM) and electric circuit model (ECM). Finite element method (FEM) is used to obtain the nonlinear relationships among the flux linkage, displacement and current off-line. The information is then used for subsequent fast simulation of the dynamic characteristics of the contactor. A set of periodically inter-transferred dynamic characteristic equations are built and the complete making dynamic process of the PM contactor is simulated using 4th-order Runge-Kutta method. Experiments are carried out to validate the proposed control method on a prototype.
Article
Full-text available
In this paper, a hybrid filter topology is proposed to reduce torque pulsation, switching voltage harmonics and EMI noises in PMSM with direct torque hysteresis controllers. The filter topology consists of IGBT-based active filter (AF), LC filter in the main inverter output and trap filter in the motor side. The coupling of the AF-compensated voltage and the motor main voltage is achieved through series transformer. The AF is characterized by detecting the harmonics in the motor phase voltages and uses hysteresis voltage control method to provide almost sinusoidal voltage to the motor windings. The active filter uses hysteresis voltage controller while the motor main circuit uses hysteresis direct torque control. The simulation results of this combined control structure show considerable torque ripple or pulsation reduction in steady state range and adequate dynamic torque performance as well as considerable harmonics and EMI noise reduction.
Conference Paper
Full-text available
The purpose of this paper is to propose new analytical approximations for fringing flux calculations around the air gaps of inductor cores, including multiple gap cases and different symmetrical cases. Existing 3D techniques using finite element analysis are accurate but require a prohibitive amount of simulation time and special software. We propose an improved analytical approximation for fringing permeance calculation for the most usual field patterns. The approach is extended form 2D to 3D giving analytical solutions for corner effects, thus providing a better accuracy of the approximation. The derived fringing coefficients are used to present all symmetrical cases and cases with multiple air gaps. The accuracy of the proposed equations is sufficient for a normal engineering design. The advantages of analytical approximations are the possibility of generating diagrams, of solving the reverse problems and optimizing more complex problems.
Article
Full-text available
This paper presents an advanced finite-element model for analyzing the dynamic behavior of electromechanical devices. The numerical approach includes nonlinear supply circuits, eddy-current and hysteresis effects, and mechanical quantities. The motion of the armature can be handled by means of two alternative approaches, based on the overlapping mesh or on the coupling of finite-element and boundary-element methods. The paper validates the model by comparing it to experimental results on an ac electromagnet with shading rings and then applies it to the analysis of fast actuators.
Article
In the paper both general and simplified reliability models of contacts used in electromagnetic power contactors are presented. The models are based on digital simulation of contact-wearing processes. The general model can be used for the estimation of influence of material and design parameters as well as operating conditions on contact durability while the simplified one is meant for forecasting new contact durability by means of simplified quality tests carried out on samples of brand new contactors.
Article
In the paper a method of "gamma-beta" durability determination of AC electromagnetic contactors is presented. Based on reliability models of essential contactor sub-assemblies, the method enables to estimate durability of the "gamma " part of the overall contactor population at the specified confidence level "beta". The method is meant for industrial laboratories which carry out reliability tests of brand-new AC contactors.
Article
This paper considers the control of solenoid valve actuators used for gas exchange in internal combustion engines. Solenoid valves offer performance benefits over traditional camshaft-based valve timing. Maintaining the impact velocity of the armature and valve is an important performance specification. Flatness-based control provides linear stable tracking error dynamics assuming voltage control. In order to incorporate voltage constraints, magnetic saturation, and to ensure an appropriate position-velocity-acceleration profile, the fiat output is parameterized with a spline basis. Non-linear programming is used to obtain optimal spline coefficients for the fiat output trajectory.
Article
The present paper deals with the modeling of wind turbine generation systems. The model of a doubly fed induction generator, along with the corresponding converter, crow bar protection and electrical grid is described. The different level control strategies both in normal operation and under voltage dig conditions are discussed, including speed control, torque and reactive power control for the rotor-side converter, reactive and DC voltage control for the grid-side converter and the corresponding current loops control. The results obtained with simulations are compared to experimental data obtained from voltage sags provoked to real wind turbines.
Article
This paper develops an estimator of the kinematics of the movable parts of any AC powered contactor. This estimator uses easily measurable electrical variables such as the voltage across the coil terminals and the current flowing through the main coil of the contactor. Hence, a low cost microcontroller would be able to implement a control algorithm in order to reduce the undesirable phenomenon of contact bounce, which causes severe erosion of the contacts and dramatically reduces the electrical life and reliability of the contacts. To develop such an estimator is essential to have at our disposal a robust model of the contactor. Therefore, a rigorous parametric model that allows us to predict the dynamic response of the AC contactor is proposed. It solves the mechanic and electromagnetic coupled differential equations that govern the dynamics of the contactor by applying a Runge–Kutta-based solver. Several approaches have been described in the technical literature. Most of them are based on high cost computational finite elements method or on simplified parametric models. The parametric model presented here takes into account the fringing flux and deals with shading rings interaction from a general point of view, thus avoiding simplified assumptions. Copyright © 2008 John Wiley & Sons, Ltd.
Article
In the paper a method of “gamma-beta” durability determination of AC electromagnetic contactors is presented. Based on reliability models of essential contactor sub-assemblies, the method enables to estimate durability of the “gamma” part of the overall contactor population at the specified confidence level “beta”. The method is meant for industrial laboratories which carry out reliability tests of brand-new AC contactors.
Article
In the paper both general and simplified reliability models of contacts used in electromagnetic power contactors are presented. The models are based on digital simulation of contact-wearing processes. The general model can be used for the estimation of influence of material and design parameters as well as operating conditions on contact durability while the simplified one is meant for forecasting new contact durability by means of simplified quality tests carried out on samples of brand new contactors.
Article
This paper reports a thorough investigation into the magnetic field of an ac permanent-magnet contactor and its control principles. Such contactors offer many advantages over conventional electromagnetic contactors in terms of energy saving and reliability. The simulation model, which couples the interaction of the magnet, circuit, and motion, is synthesized using MATLAB software. In order to speed up the simulation process, the model computes the nonlinear relationships of displacement, flux linkage, and current separately, using the finite-element method. We report simulation results for various phase angles of current flowing in the full bridge rectifier at full voltage. We have validated the calculated static force and the dynamic simulation experimentally.
Article
This paper describes the fabrication and characterisation of 2-dimensional inductive devices integrated inside printed circuit boards (PCB) and flex-foils. These devices basically are composed of three layers of which the outer layers bear the printed coil patterns and the inner layer is a high permeability ferromagnetic sheet core. Both magnetic metal and copper layers are patterned using standard lithographic techniques. Electroplated interconnections between the outer layers complete the windings. We have fabricated both transformers and fluxgate magnetic field sensing devices with a thickness of 200 μm for the flex-foil devices and 600 μm for the PCB-based devices. Lateral dimensions are approximately 1 cm. We realise relatively high inductances of 1–10 μH at a frequency of 1 kHz for the transformers and a magnetic field detection limit of 43 μT at 20 kHz for the fluxgate devices.
Article
The double-break arrangement of dc-contactors is advantageous for electrical arc quenching, so the most important disadvantage of the double-break, the higher temperature rise during current carrying operation, is acceptable. However, overheating can be a serious problem. In this paper, a mathematical model is proposed for the steady-state temperature difference distribution of double-break dc-contactors and an experimental verification of the theoretical results attempted. The influence of different dc-contactors’ parameters on the temperature distribution is investigated, and it is convincingly shown that the heat generated is dissipated mainly by the conductors, and that this dominates the optimisation of the dc-contactor temperature rise.
Article
This paper presents a speed estimation technique for the permanent magnet synchronous motor drive. A Model Reference Adaptive System (MRAS) has been formed using the instantaneous and steady-state reactive powers to estimate the speed. It has been shown that such unique MRAS offers several desirable features. The proposed technique is completely independent of stator resistance and is less parameter sensitive, as the estimation-algorithm is only dependent on q-axis stator inductance. Also, the method requires less computational effort as the simplified expressions are used in the MRAS. The stability of the proposed system is achieved through Popov’s Hyperstability criteria. Extensive simulation results are presented to validate the proposed technique. The system is tested at different speeds including zero speed and a very satisfactory performance has been achieved.
Conference Paper
The traditional engine valve train in a combustion engine is the mechanically driven camshaft system that provides one-fixed valve timing. The variable valve timing (VVT), however, is highly required to achieve the significant improvement in fuel economy. To provide the VVT, the two-solenoid type of actuator had been developed in past years, but it requires current in all operation period, the starting is difficult and the efficiency is low. In this paper, a new linear actuator using permanent magnet (PM) is proposed and verified its feasibility by finite element (FE) analysis
Conference Paper
This paper proposes a model for the dynamic analysis of AC contactors. The model equations are presented and the implementation of the calculation algorithm is discussed. The high calculation speed of the implemented algorithm allows an extensive set of voltage sags to be studied, and their impact on the contactor performance to be analyzed. The contactor sensitivity CBEMA curves are obtained for different initial voltage phases at the voltage drop point. In particular, the CBEMA curve for 90° of initial voltage phase (i.e. when the voltage at the start of the sag is zero) is studied and justified.
Conference Paper
This paper presents a dynamic simulator for analyzing various behaviors of electromagnetic contactors with AC solenoids. The simulator enables short-time analysis of dynamic motions of contactors compared with conventional simulation methods such as finite element method (FEM). To realize fast calculation of contactor models, whole contactor system including electromagnetic circuit, and mechanism (motions and collisions) are described and modeled by differential equations. The differential equations are solved simultaneously by the Runge-Kutta method. The short-time analysis by the dynamic simulator allows contactor designers to test various changes of parameters of a contactor such as dimensions of solenoid, power voltage and the phase, mass and inertia of mechanical parts, environment temperature, etc. In the paper dynamic modeling of contactors and the simulation algorithm using the mathematical models are described in detail followed by the comparison with experimental results for verifying the utility of the dynamic simulator.
Article
This brief considers the control of solenoid valve actuators used for gas exchange in internal combustion engines. Although solenoid valves offer performance benefits over traditional camshaft-based valve systems, maintaining low impact velocity is a critical performance requirement. Flatness provides a convenient framework for meeting a number of performance specifications on the valve's end motion. The proposed control design incorporates voltage constraints, nonlinear magnetic effects, and various motion planning requirements. A flat output acts as a design parameter and is parameterized with a spline basis. A nonlinear feasibility problem is solved to obtain optimal spline coefficients such that performance requirements are met. The resulting flat output provides an open-loop control which is augmented with feedback so that a linear stable tracking error system results. The proposed control scheme is demonstrated in simulation and on an experimental testbed. The performance of a proportional-integral controller is compared experimentally to the flatness-based method
Article
This paper develops a robust and fast parametric model to describe the dynamic behavior of an ac contactor. The model solves simultaneously the mechanical and electromagnetic coupled differential equations that govern its dynamic response. It deals with the shading rings and takes into account the fringing flux. Data from simulations carried out by applying the presented parametric model are compared with experimental data, demonstrating the model's validity and effectiveness.
Article
We describe a new moving-iron electromagnetic actuator that utilizes cantilever-beam-type springs, π type armature, full-bridge magnetic circuits, and a single driving coil. The actuator is suitable for electromechanical converters with high response and minor displacement for use in electronic engraving systems. We analyzed its static and dynamic characteristics by using a three-dimensional finite-element method. We used a simple and practical measuring method based on light reflection to detect the actuator's real hysteresis loop and amplitude frequency response characteristics. The results show that the actuator has a displacement of ±65 μm, hysteresis of less than 5.5%, and amplitude cutoff frequency of 3.1 kHz. We tested the actuator on a real engraving system and confirmed its characteristics by the engraving results.
Article
The paper describes a type of variable air-gap reluctance actuator that offers potential for enhancing the dynamic performance of electromagnetic valve actuation systems for internal combustion engines. In both the stator and armature, the actuator incorporates design features that allow the force-displacement characteristic to be tailored to meet operational requirements. The paper demonstrates the considerable scope for varying actuator characteristics by means of detailed two- and three-dimensional finite-element modeling. The key findings from the finite-element modeling are validated by experimental measurements on a prototype actuator.
Modeling and control of the doubly fed induction generator wind turbine, Simulation Modelling Practice and Theory
  • Adrià Junyent-Ferré
  • Andreas Bellmunt
  • Marc Sumper
  • Montserrat Sala
  • Mata
Adrià Junyent-Ferré, Oriol Gomis-Bellmunt, Andreas Sumper, Marc Sala, Montserrat Mata, Modeling and control of the doubly fed induction generator wind turbine, Simulation Modelling Practice and Theory 18 (9) (2010) 1365–1381.