This work presents a range optimization of a SynRM (synchronous reluctance motor) and a PMaSynRM (permanent-magnet-assisted synchronous reluctance motor) according to a standard driving cycle, and the solutions obtained are compared. The proposed approach avoids the use of finite element analysis (FEA) during the optimization process, thus greatly reducing the time required to obtain the optimal solution. The paper validates the optimal motors obtained in different domains, since the methodology takes into account a multi-physics design. Using two coupled reluctance and thermal networks, all possible working points in the torque-speed plane are obtained taking into account thermal effects, magnetic saturation, iron losses as well as voltage and current constraints imposed by the inverter. The proposed approach allows a fast comparison of the solutions attained. The design and optimization methodology presented in this work can be applied to any driving cycle.
Air gap eccentricity faults in five-phase ferrite-assisted synchronous reluctance motors (fPMa-SynRMs) tend to distort the magnetic flux in the air gap, which in turn affects the spectral content of both the stator currents and the ZSVC (zero-sequence voltage component). However, there is a lack of research works dealing with the topic of fault diagnosis in multi-phase PMa-SynRMs, and in particular, focused to detect eccentricity faults. The analysis of the spectral components of the line currents and the ZSVC, allows developing fault diagnosis algorithms to detect eccentricity faults. The effect of the operating conditions is also analyzed, since this paper shows that it has a non-negligible impact on the effectivity and sensitivity of the diagnosis based on the analysis of the stator currents and the ZSVC. To this end, different operating conditions are analyzed. The paper also evaluates the influence of the operating conditions on the harmonic content of the line currents and the ZSVC, and determines the most suitable operating conditions to enhance the sensitivity of the analyzed methods. Finally, fault indicators to detect eccentricity faults, which are based on the spectral content of the stator currents and the ZSVC are derived, and their performance is assessed. The approach presented in this work may be useful to develop fault diagnosis strategies based on the acquisition and subsequent analysis and interpretation of the spectral content of the line currents and the ZSVC.
the development of different topologies of power converters with impedance networks have opened up new lines of research, its application in different areas such as transmission systems, high voltage, photovoltaic systems, these have yielded systems with high performance and efficiency, but in recent years its application in research and development of traction systems for electric vehicles have in creased, these topologies can be bidirectional and replace the DC-DC booster used in conventional systems. However, its implementation is necessary to
know the different modulation techniques and control that can be used to reach more efficient traction system and to consolidate these topologies. This article describes the different modulation and control techniques that can be applied to converter topologies with bidirectional impedance networks for applications in traction systems for electric vehicle.
Kampouropoulos, K.; Andrade, F.; Sala, E.; Garcia, A.; Romeral, L. IEEE Transactions on Smart Grid Vol. PP, num. 99, p. 1-9 DOI: 10.1109/TSG.2016.2609740 Data de publicació: 2016-09-14 Article en revista
This paper presents a novel method for the energy optimization of multi-carrier energy systems. The presented method combines an adaptive neuro-fuzzy inference system, to model and forecast the power demand of a plant, and a genetic algorithm to optimize its energy flow taking into account the dynamics of the system and the equipment’s thermal inertias. The objective of the optimization algorithm is to satisfy the total power demand of the plant and to minimize a set of optimization criteria, formulated as energy usage, monetary cost and environmental cost. The presented method has been validated under real conditions in the car manufacturing plant of SEAT in Spain in the framework of an FP7 European research project.
Giacometto, Francisco javier; Capelli, F.; Romeral, L.; Riba, J.; Sala, E. Advances in Electrical and Computer Engineering Vol. 16, num. 3, p. 25-30 DOI: 10.4316/AECE.2016.03004 Data de publicació: 2016-08-15 Article en revista
Wang, C.; Delgado Prieto, M.; Romeral, L.; Chen, Z.; Blaabjerg, F.; Liu, X. IEEE transactions on magnetics Vol. 52, num. 7 DOI: 10.1109/TMAG.2015.2511003 Data de publicació: 2016-07-01 Article en revista
Demagnetization fault detection of in-service permanent magnet synchronous machines (PMSMs) is a challenging task, because most PMSMs operate under nonstationary circumstances in industrial applications. A novel approach based on tracking characteristic orders of stator current using Vold-Kalman filter is proposed to detect the partial demagnetization fault in PMSMs running at nonstationary conditions. The amplitude of envelope of the fault characteristic orders is used as fault indictor. Experimental results verify the superiority of the proposed method on the partial demagnetization online fault detection of PMSMs under various speed and load conditions.
Several factors including fossil fuels scarcity, prices volatility, greenhouse gas emissions or current pollution levels in metropolitan areas are forcing the development of greener transportation systems based on more efficient electric and hybrid vehicles. Most of the current hybrid electric vehicles use electric motors containing powerful rare-earth permanent magnets. However, both private companies and estates are aware of possible future shortages, price uncertainty and geographical concentration of some critical rare-earth elements needed to manufacture such magnets. Therefore, there is a growing interest in developing electric motors for vehicular propulsion systems without rare-earth permanent magnets. In this paper this problematic is addressed and the state-of-the-art of the electric motor technologies for vehicular propulsion systems is reviewed, where the features required, design considerations and restrictions are addressed.
The use of impedance networks in different types of DC/DC, DC/AC and AC/AC converters, has increased significantly, and many converters topologies and articles VSI and CSI with impedance networks have been presented for the purpose of overcoming the limitations and problems of voltage and current that frequently occurs in these topologies. The selection and implementation of a topology of network impedance would improve the reliability and performance of the power system. This article presents a study and analysis of different network impedance topologies, the modulation techniques and control for the adapting to power converters for applications in electric traction.
the traction systems for electric vehicles have advanced considerably over recent years, with the application of different topologies of power converters for the control of various types of electric induction motors and permanent magnet. Furthermore, the evolution of power semiconductor elements of Si to SiC wideband have opened up lines of research and development in this area. The trend of manufacturer's traction systems is to reach compact systems where the power dissipation is high and the reduction of losses is minimal, for it the implementation of topologies of converters with SiC devices seems to be a good alternative of use to improve the performance of these systems; This paper describes a study and review of the different types of converter topologies proposed for the development and application in traction systems for electric vehicles. This review will identify the different works presented and analyze their problems, with the aim of seek to optimize these topologies or propose new types of topologies for implementation in traction systems.
Delgado Prieto, M.; Zurita, D.; Wang, W.; Machado, A.; Ortega, J.A.; Romeral, L. IEEE transactions on instrumentation and measurement Vol. 65, num. 1, p. 15-24 DOI: 10.1109/TIM.2015.2476278 Data de publicació: 2016-01-01 Article en revista
Advanced sensing strategies in the industrial sector are becoming a valued technological answer to increase the performance and competitiveness. The development of enhanced sensing solutions considering both technology and monitoring requirements is, nowadays, subject of concern in the industrial maintenance field. In this context, this paper presents a novel self-powered wireless sensor applied to condition monitoring of gears. The proposed sensor is based on a modular architecture, offering multipoint sensing, local wireless communication, multisource energy harvesting, and embedded diagnosis algorithm for mechanical fractures detection based on acoustic emission analysis. The developments are complemented by means of a remote management interface, from which the user can configure the functionalities of the sensors, visualize the network status as well as analyze the diagnosis evolution. The sensor performance, in terms of power consumption and fault detection, has been analyzed by means of experimental results.
Romeral, L.; Salehi Arashloo, R.; Salehifar, M.; Moreno-Eguilaz, J.M. Electric power systems research Vol. 121, p. 260-269 DOI: 10.1016/j.epsr.2014.11.004 Data de publicació: 2015-04-01 Article en revista
Model predictive control algorithms have recently gained more importance in the field of wind power generators. One of the important categories of model predictive control methods is improved deadbeat control in which the reverse model of generator is used to calculate the appropriate inputs for the next iteration of controlling process. In this paper, a new improved deadbeat algorithm is proposed to control the stator currents of an outer-rotor five-phase BLDC generator. Extended Kalman filter is used in the estimation step of proposed method, and generator equations are used to calculate the appropriate voltages for the next modulation period. Two aspects of proposed controlling method are evaluated including its sensitivity to generator parameter variations and its speed in following the reference values of required torque during transient states. Wind power generators are kept in mind, and proposed controlling method is both simulated and experimentally evaluated on an outer-rotor five-phase BLDC generator. (C) 2014 Elsevier B.V. All rights reserved.
This work analyzes the behavior of surface-mounted permanent magnet synchronous motors (SPMSMs) operating under stator faults. The studied faults are resistive unbalance and winding inter-turn short circuits, which may lead to unbalanced conditions of the motor. Both faults may reduce motor efficiency and performance and produce premature ageing. This work develops an analytical model of the motor when operating under stator faults. By this way, the theoretical basis to understand the effects of resistive unbalance and stator winding inter-turn faults in SPMSMs is settied. This work also compares two methods for detecting and discriminating both faults. For this purpose, a method based on the analysis of the zero-sequence voltage component is presented, which is compared to the traditional method, i.e. the analysis of the stator currents harmonics. Both simulation and experimental results presented in this work show the potential of the zero-sequence voltage component method to provide helpful and reliable data to carry out a simultaneous diagnosis of resistive unbalance and stator winding inter-turn faults.
La publicación final está disponible en Springer a través de 10.1007/s00202-014-0316-z
Fault tolerant control of five-phase brushless direct current (BLDC) machines is gaining more importance in high-safety applications such as offshore wind generators and automotive industries. In many applications, traditional controllers (such as PI controllers) are used to control the stator currents under faulty conditions. These controllers have good performance with dc signals. However, in the case of missing one or two of the phases, appropriate reference currents of these machines have oscillatory dynamics both in phase- and synchronous-reference frames. Non-constant nature of these reference values requires the implication of fast current controllers. In this paper, model predictive deadbeat controllers are proposed to control the stator currents of five-phase BLDC machines under normal and faulty conditions. Open circuit fault is considered for both one and two stator phases, and the behaviour of proposed controlling method is evaluated. This evaluation is generally focused on first, sensitivity of proposed controlling method and second, its speed in following reference current values under transient states. Proposed method is simulated and is verified experimentally on a five-phase BLDC drive. (C) 2015 Elsevier Ltd. All rights reserved.
Electric motors used for traction purposes in electric vehicles (EVs) must meet several requirements, including high efficiency, high power density and faulttolerance. Among them, permanent magnet synchronous motors (PMSMs) highlight. Especially, five-phase axial flux permanent magnet (AFPM) synchronous motors are particularly suitable for in-wheel applications with enhanced fault-tolerant capabilities. This paper is devoted to optimally design an AFPM for in-wheel applications. The main geometric, electric and mechanical parameters of the designed AFPM are calculated by applying an iterative method based on a set of analytical equations, which is assisted by means of a reduced number of three-dimensional finite element method (3D-FEM) simulations to limit the computational burden. To optimally design the AFPM, a constrained multi-objective optimization process based on a genetic algorithm is applied, in which two objective functions are considered, i.e. the power density and the efficiency. Several fault-tolerance constraints are settled during the optimization process to ensure enhanced fault-tolerance in the resulting motor design. The accuracy of the best solution attained is validated by means of 3D-FEM simulations.
Salehifar, M.; Salehi Arashloo, R.; Moreno-Eguilaz, J.M.; Sala, V.; Romeral, L. IET power electronics Vol. 8, num. 1, p. 76-87 DOI: 10.1049/iet-pel.2013.0949 Data de publicació: 2015-01-01 Article en revista
To meet increasing demand for higher reliability in power electronics converters applicable in electric vehicles, fault detection (FD) is an important part of the control algorithm. In this study, a model-based open transistor fault diagnsosis method is presented for a voltage-source inverter (VSI) supplying a five-phase permanent magnet motor drive. To realise this goal, a model-based observer is designed to estimate model parameters. After that, the estimated parameters are used to design a sliding mode observer in order to estimate the phase current in an ideal model. Subsequently, the proposed FD technique measures the similarity between the estimated current and real current using cross-correlation factor. This factor is used for the first time in this study to define a FD index in VSI. The presented FD scheme is simple and fast; also, it is able to detect multiple open switch or open phase faults in contrast to conventional methods. On the other side, in order to track reference current of the motor, the estimated parameters are used to design a proportional resonant controller. The FD technique is used to operate a multiphase fault-tolerant brushless direct current (BLDC) motor drive. Experimental results on a five-phase BLDC motor with in-wheel outer rotor applicable in electrical vehicles are conducted to validate the theory.
Five-phase permanent magnet synchronous motors (PMSMs) have inherent fault-tolerant capabilities. This paper analyzes the detection of inter-turn short circuit faults in five-phase PMSMs in their early stage, i.e. with only one turn in short circuit by means of the analysis of the stator currents and the zero-sequence voltage component (ZSVC) spectra. For this purpose, a parametric model of five-phase PMSMs which accounts for the effects of inter-turn short circuits is developed to determine the most suitable harmonic frequencies to be analyzed to detect such faults. The amplitudes of these fault harmonic are analyzed in detail by means of finite-elements method (FEM) simulations, which corroborate the predictions of the parametric model. A low-speed five-phase PMSM for in-wheel applications is studied and modeled. This paper shows that the ZSVC-based method provides better sensitivity to diagnose inter-turn faults in the analyzed low-speed application. Results presented under a wide speed range and different load levels show that it is feasible to diagnose such faults in their early stage, thus allowing applying a post-fault strategy to minimize their effects while ensuring a safe operation.
The study of the dynamic behaviour of electric vehicles is being incorporated in the syllabuses of an increasing number of graduate and undergraduate courses. This paper analyses the basic mechanical and electric concepts of electric traction applied to automobiles. For this purpose, in this work the switched reluctance motor is analysed. A model based on MATLAB/Simulink to simulate the behaviour of both the electric motor and the vehicle dynamics is described. It allows students to gain a better understanding of the fundamental mechanical and electrical concepts by simulating the system behavior in an interactive and flexible manner.
Salehi Arashloo, R.; Romeral, L.; Salehifar, M.; Moreno-Eguilaz, J.M. IET electric power applications Vol. 8, num. 7, p. 267-277 DOI: 10.1049/iet-epa.2013.0247 Data de publicació: 2014-08-01 Article en revista
This study presents a method to improve the output power of five-phase brushless direct current (BLDC) motors under different faulty conditions. Different machine connections are considered while having open-circuit fault in one and two stator phases, and both fundamental and third harmonic component of stator currents are controlled to improve the amplitude and quality of generated torque under faulty conditions. Rated root-mean-square value of stator phase currents is considered as the main limiting factor of generated electrical torque. Genetic algorithm is used in the optimisation procedure of stator reference currents to gain more output power under the fault. Automotive applications are kept in mind, and to verify the theoretical developments, experimental tests are conducted on a five-phase BLDC motor with in-wheel outer-rotor configuration.
In this paper, a new method for modeling converterbased power generators in ac-distributed systems is proposed. It is
based on the concept of electrostatic synchronous machines. With this new concept, it is possible to establish a simple relationship between the dc and ac side and to study stability in both the small and large signals of the microgrid by considering a dc-link dynamic
and high variation in the power supplied. Also, for the purpose of illustration, a mathematical and electrical simulation is presented, based on MATLAB and PSCAD software. Finally, an experimental
test is performed in order to validate the new model.
In many countries worldwide, the energy demand is growing faster than the transmission capacity. However, due to environmental constrains, social concerns and financial costs, the construction of new power transmission lines is an arduous task. In addition, power transmission systems are often loaded close to their nominal values. Therefore, improving power transmission system efficiency and reliability is a matter of concern. This work deals with a 400 kV, 3000 A, 50 Hz extra-high-voltage expansion substation connector used to connect two substation bus bars of 150 mm diameter each. This substation connector has four aluminum wires which provide the conductive path between both bus bars. Preliminary tests showed an unequal current distribution through the wires which was mainly attributed to the proximity effect. A three-dimensional finite elements method approach was applied to improve the design and evaluate the electromagnetic and thermal behavior of both the original and improved versions of the connector. Experimental tests made under laboratory conditions have validated the accuracy of the simulation method presented in this paper, which may be a valuable tool to assist the design process of substation connectors, therefore allowing improving both the thermal performance and reliability of the redesigned connectors.
Interturn faults in permanent magnet synchronous motors (PMSMs) may develop fast into more severe faults such as coil-to-coil, phase-to-phase and phase-to-ground short circuits. These faults are very destructive and may irreversibly damage the PMSM. Therefore, it is highly desirable to develop suitable methods for the early detection of such faults. The effects of interturn faults are visible in both the stator currents and the zero-sequence voltage component (ZSVC) spectra. By designing appropriate fault diagnosis schemes based on the analysis of the harmonic content of such electric variables it is possible to detect short circuit faults in its early stage. However, the stator winding configuration of the PMSM deeply impacts the harmonic content of both spectra. This paper studies the effects of different stator winding configurations in both the stator currents and the ZSVC spectra of healthy and faulty machines. Results presented may help to develop fault diagnosis schemes based on the acquisition and further analysis of the stator currents and/or the ZSVC harmonic components.
This paper shows the capabilities of applying the three-dimensional finite element method (3D-FEM) for designing complex-shaped substation connectors to operate at 765 kVRMS AC. To check this methodology, it was analyzed the feasibility of upgrading a 400 kVRMS substation connector to operate at 765 kVRMS. However, both experimental and simulation results conducted according to the ANSI/NEMA CC 1-2009 standard concluded that although it passed the visual corona test, to ensure a wide safety margin it was desirable an improvement of the electrical behavior of such connector. It was shown that FEM results allowed detecting the peak stress points of the connector regarding the electrical stress thus allowing applying a corrective action. Then, two possible solutions were analyzed, i.e. the use of corona shields and the redesign of the connector assisted by 3D-FEM simulations. Results presented in this work show that both approaches have an excellent behavior in reducing the electric field strength on the connector surface. However, to make the final decision, the production cost of both alternatives was analyzed, thus favoring the redesign option. Next, the redesigned version of the substation connector was manufactured and tested. Experimental results conducted in a high voltage laboratory verified the effectiveness of the methodology and the potential of the proposed system to act as an advanced design tool for optimizing the behavior of complex-shaped substation connectors. Thus, this system allows assisting efficiently the design process while permitting constraining the economic costs
Kampouropoulos, K.; Andrade, F.; Garcia, A.; Romeral, L. Advances in Electrical and Computer Engineering Vol. 14, num. 1, p. 9-14 DOI: 10.4316/AECE.2014.01002 Data de publicació: 2014-02-01 Article en revista
This document presents an energy forecast methodology using Adaptive Neuro-Fuzzy Inference System (ANFIS) and Genetic Algorithms (GA). The GA has been used for the selection of the training inputs of the ANFIS in order to minimize the training result error. The presented algorithm has been installed and it is being operating in an automotive manufacturing plant. It periodically communicates with the plant to obtain new information and update the database in order to improve its training results. Finally the obtained results of the algorithm are used in order to provide a short-term load forecasting for the different modeled consumption processes.
This document presents an energy forecast methodology using Adaptive Neuro-Fuzzy Inference System (ANFIS) and Genetic Algorithms (GA). The GA has been used for the selection of the training inputs of the ANFIS in order to minimize the training result error. The presented algorithm has been installed and it is being operating in an automotive manufacturing plant. It periodically communicates with the plant to obtain new information and update the database in order to improve its training results. Finally the obtained results of the algorithm are used in order to provide a shortterm load forecasting for the different modeled consumption processes.
Atashkhooei, R.; Urresty, J.; Royo, S.; Riba, J.; Romeral, L. IEEE-ASME transactions on mechatronics Vol. 19, num. 1, p. 184-190 DOI: 10.1109/TMECH.2012.2226739 Data de publicació: 2014-01-17 Article en revista
Salehi Arashloo, R.; Romeral, L.; Salehifar, M.; Sala, V. Advances in Electrical and Computer Engineering Vol. 14, num. 2, p. 89-96 DOI: 10.4316/AECE.2014.02015 Data de publicació: 2014 Article en revista
Efficiency improvement under faulty conditions is one of the main objectives of fault tolerant PM drives. This goal can be achieved by increasing the output power while reducing the losses. Stator copper loss not only directly affects the total efficiency, but also plays an important role in thermal stress generations of iron core. In this paper, the effect of having control on neutral point current is studied on the efficiency of five-phase permanent magnet machines. Open circuit fault is considered for both one and two phases, and the distribution of copper loss along the windings are evaluated in each case. It is shown that only by having access to neutral point, it is possible to generate less stator thermal stress and more mechanical power in five-phase permanent magnet generators. Wind power generation and their applications are kept in mind, and the results are verified via simulations and experimental tests on an outer-rotor type of five-phase PM machine.
Salehi Arashloo, R.; Salehifar, M.; Saavedra, H.; Romeral, L. Advances in Electrical and Computer Engineering Vol. 14, num. 2, p. 145-152 DOI: 10.4316/AECE.2014.02023 Data de publicació: 2014 Article en revista
Fault tolerant motor drives are an interesting subject for many applications such as automotive industries and wind power generation. Among different configurations of these systems, five-phase BLDC drives are gaining more importance which is because of their compactness and high efficiency. Due to replacement of field windings by permanent magnets in their rotor structure, the main sources of power losses in these drives are iron (core) losses, copper (winding) losses, and inverter unit (semiconductor) losses. Although low amplitude of power losses in five-phase BLDC drives is an important aspect for many applications, but their efficiency under faulty conditions is not considered in previous studies. In this paper, the efficiency of an outer-rotor five phase BLDC drive is evaluated under normal and different faulty conditions. Open-circuit fault is considered for one, two adjacent and two non-adjacent faulty phases. Iron core losses are calculated via FEM simulations in Flux-Cedrat® software, and moreover, inverter losses and winding copper losses are simulated in MATLAB® environment. Experimental evaluations are conducted to evaluate the efficiency of the entire BLDC drive which verifies the theoretical developments.
Salehifar, M.; Salehi Arashloo, R.; Moreno-Eguilaz, J.M.; Sala, V.; Romeral, L. IEEE Journal of emerging and selected topics in power electronics num. 99 DOI: 10.1109/JESTPE.2013.2293518 Data de publicació: 2013-12-03 Article en revista
Urresty, J.; Atashkhooei, R.; Riba, J.; Romeral, L.; Royo, S. IEEE transactions on industrial electronics Vol. 60, num. 8, p. 3454-3461 DOI: 10.1109/TIE.2012.2213565 Data de publicació: 2013-08-01 Article en revista
Demagnetization faults have a negative impact on the behavior of permanent-magnet synchronous machines, thus reducing their efficiency, generating torque ripple, mechanical vibrations, and acoustic noise, among others. In this paper, the displacement of the shaft trajectory induced by demagnetization faults is studied. It is proved that such faults may increase considerably the amplitude of the rotor displacement. The direct measure of the shaft trajectory is performed by means of a noncontact self-mixing interferometric sensor. In addition, the new harmonics in the back electromotive force (EMF) and the stator current spectrum arising from the shaft displacement are analyzed by means of finite-element method (FEM) simulations and experimental tests. Since conventional finite-element electromagnetic models are unable to predict the harmonics arising from the shaft trajectory displacement, an improved finite-element model which takes into account the measured trajectory has been developed...
Abstract—Demagnetization faults have a negative impact on the behavior of permanent-magnet synchronous machines, thus
reducing their efficiency, generating torque ripple, mechanical vibrations, and acoustic noise, among others. In this paper, the
displacement of the shaft trajectory induced by demagnetization faults is studied. It is proved that such faults may increase considerably the amplitude of the rotor displacement. The direct measure of the shaft trajectory is performed by means of a noncontact self-mixing interferometric sensor. In addition, the new harmonics
in the back electromotive force (EMF) and the stator current spectrum arising from the shaft displacement are analyzed by means
of finite-element method (FEM) simulations and experimental tests. Since conventional finite-element electromagnetic models are
unable to predict the harmonics arising from the shaft trajectory displacement, an improved finite-element model which takes into account the measured trajectory has been developed. It is shown that this improved model allows obtaining more accurate back EMF and stator current spectra than those obtained by means of
conventional models. This work presents a comprehensive analysis of the effects generated by demagnetization faults, which may be useful to develop improved fault diagnosis schemes
Demagnetization faults in permanent magnet synchronous motors may generate specific fault harmonic frequencies in the stator currents and the zero-sequence voltage component (ZSVC) spectra. Hence, by analyzing the stator currents or/and the ZSVC spectra it is possible to develop fault diagnosis schemes to detect such faults. In order to have a broad view of such effects, a representative set of stator windings configurations must be considered. By analyzing different stator windings configurations this paper shows that the amplitude of the harmonic frequencies of both the stator currents and the ZSVC spectrato be analyzed are significantly influenced by the stator windings configuration. It is also proved that depending on the winding configuration, new harmonic components may emerge in both spectra. The results presented in this paper may help to develop fault diagnosis schemes based on the acquisition and further analysis of the stator currents and the ZSVC harmonic components.
Andrade, F.; Kampouropoulos, K.; Cusido, J.; Romeral, L. Advances in Electrical and Computer Engineering Vol. 13, num. 3, p. 17-22 DOI: 10.4316/AECE.2013.03003 Data de publicació: 2013 Article en revista
This paper presents a phase-plane trajectory analysis and the appliance of Lyapunov´s methodology to evaluate the stability limits of a small signal model of a Microgrid system. The work done is based on a non-linear tool and several computer simulations. The study indicates how to analyze a Microgrid system that is subjected to a severe transient disturbance by using its large signal model without the necessity of the small signal analysis as it is commonly applied.
This paper presents a phase-plane trajectory
analysis and the appliance of Lyapunov´s methodology to evaluate the stability limits of a small signal model of a Microgrid system. The work done is based on a non-linear tool and several computer simulations. The study indicates how to
analyze a Microgrid system that is subjected to a severe transient disturbance by using its large signal model without the necessity of the small signal analysis as it is commonly applied.
Demagnetization faults are troublesome because they have a profound impact on the overall performance of permanent magnet synchronous motors (PMSMs). This work presents and veri¿es experimentally a system to detect such faults which is based on the measure of the zero sequence voltage component (ZSVC). The proposed method is also appropriate for inverter fed machines and is particularly useful when dealing with fault tolerant systems. A fault severity index which allows quantifying the harshness of such faults is also proposed and its behavior is analyzed from experimental data. Features of the proposed method include low computational burden, simplicity and high sensitivity. Experimental results conducted at different speed and load conditions show the potential of the proposed fault severity index for online diagnosis of demagnetization failures
Interturn faults in permanent magnet synchronous
machines may have very harmful effects if not early identified. This study deals with the detection of such faults when the machine operates under varying speed conditions. The performance of two methods is analyzed and compared, i.e., the analysis of the third harmonic of the stator currents and the first one of the zero-
sequence voltage components. The Vold–Kalman filtering order tracking algorithm is introduced and applied to track the harmonics of interest when the machine operates under a wide speed range and different load levels. This study also presents two reliable fault indicators especially focused to detect stator winding interturn faults under nonstationary speed conditions. Experimental results endorse the methodology proposed, showing its potential
to carry out a reliable fault diagnosis scheme
This paper develops and analyzes a methodology for detecting stator winding inter-turn faults in surface-mounted permanent magnet synchronous motors. The proposed methodology is based on monitoring the zero-sequence voltage component having into account the effects of the inverter that usually feeds the machine. The theoretical basis of such a method is established from the parametric model of the machine. Attributes of the method presented here include simplicity, high accuracy, low computational burden and high sensibility. Additionally, it is especially useful when dealing with fault tolerant systems. From this model the expression of the zero sequence voltage component is deduced, which is used to detect stator winding inter-turn faults. Both simulation and experimental results presented in this work show the potential of the proposed method to provide helpful and reliable data to carry out an online diagnosis of such faults.
This paper develops and analyzes an online methodology to detect demagnetization faults in surface-mounted permanent magnet synchronous motors. The proposed methodology, which takes into account the effect of the inverter that feeds the machine, is based on monitoring the zero-sequence voltage component of the stator phase voltages. The theoretical basis of the proposed method has been established. Attributes of the method presented here include simplicity, very low computational burden, and high sensibility. Since the proposed method requires access to the neutral point of the stator windings, it is especially useful when dealing with fault tolerant systems. A simple expression of the zero-sequence voltage component is deduced, which is proposed as a fault indicator parameter. Both simulation and experimental results presented in this paper show the potential of the proposed method to provide helpful and reliable data to carry out an online diagnosis of demagnetization failures in the rotor permanent magnets.
This paper develops and analyzes a parametric
model for simulating healthy and faulty surface-mounted permanent magnet synchronous motors. It allows studying the effects of
stator winding interturn short-circuit faults. A relevant feature of the developed model is that it deals with spatial harmonics due to a nonsinusoidal rotor permanent magnet configuration. Additionally,
the proposed model is valid for studying the behavior of these machines running under nonstationary conditions, including load
or speed variations. Stator current spectra obtained from simulations performed by applying the proposed model show a close
similitude with experimental results, highlighting the potential of such a model to understand the effects of stator winding failures on the current spectrum and allowing it to carry out an automatic
diagnosis of such faults.
Double frequency tests are used for evaluating stator windings and analyzing the
temperature. Likewise, signal injection on induction machines is used on sensorless motor
control fields to find out the rotor position. Motor Current Signature Analysis (MCSA),
which focuses on the spectral analysis of stator current, is the most widely used method for
identifying faults in induction motors. Motor faults such as broken rotor bars, bearing
damage and eccentricity of the rotor axis can be detected. However, the method presents
some problems at low speed and low torque, mainly due to the proximity between the
frequencies to be detected and the small amplitude of the resulting harmonics. This paper
proposes the injection of an additional voltage into the machine being tested at a frequency
different from the fundamental one, and then studying the resulting harmonics around the
new frequencies appearing due to the composition between injected and main frequencies.
Permanent magnet synchronous motors (PMSMs) are applied in high performance positioning and variable
speed applications because of their enhanced features with respect to other AC motor types. Fault
detection and diagnosis of electrical motors for critical applications is an active field of research. However,
much research remains to be done in the field of PMSM demagnetization faults, especially when running
under non-stationary conditions. This paper presents a time–frequency method specifically focused to
detect and diagnose demagnetization faults in PMSMs running under non-stationary speed conditions,
based on the Hilbert Huang transform. The effectiveness of the proposed method is proven by means of
Garcia, A.; Riba, J.; Cusido, J.; Ortega, J.A.; Romeral, L. IEEE transactions on components and packaging technologies Vol. 33, num. 3, p. 535-543 DOI: 10.1109/TCAPT.2010.2041456 Data de publicació: 2010-09 Article en revista
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
Early fault detection and diagnosis of high-performance electric motors has been an active area of research for the past two decades. This work presents a practical session that facilitates instructing students in this field. To meet this objective, fault diagnostic methods based on the Fourier transform and the wavelet transform are successfully applied by means of processing and examining the frequency content of the stator currents acquired from healthy and faulty permanent magnet synchronous machines (PMSMs). The goal of this practical lab is to introduce Master's degree students to the topic of fault detection by covering both stationary and nonstationary operating conditions of the motor under study. The Technical University of Catalonia (UPC) has successfully incorporated the learning methodology proposed in this paper in a practical session of an electronic engineering course. The effectiveness of the proposed practical lab has been assessed using the results of a satisfaction questionnaire answered by students involved in the course.
Early fault detection and diagnosis of high-performance electric motors has been an active area
of research for the past two decades. This work presents a practical session that facilitates instructing students
in this field. To meet this objective, fault diagnostic methods based on the Fourier transform and the wavelet
transform are successfully applied by means of processing and examining the frequency content of the stator
currents acquired from healthy and faulty permanent magnet synchronous machines (PMSMs). The goal of this
practical lab is to introduce Master’s degree students to the topic of fault detection by covering both stationary
and nonstationary operating conditions of the motor under study. The Technical University of Catalonia (UPC) has
successfully incorporated the learning methodology proposed in this paper in a practical session of an electronic
engineering course. The effectiveness of the proposed practical lab has been assessed using the results of a
satisfaction questionnaire answered by students involved in the course.
Cusido, J.; Romeral, L.; Garcia, A.; Ortega, J.A.; Riba, J. European transactions on electrical power Vol. 21, num. 1, p. 475-488 DOI: 10.1002/etep.455 Data de publicació: 2010-06-28 Article en revista
A new technique for induction motor fault detection and diagnosis is presented. This technique, which has
been experimentally verified in stationary and non-stationary motor conditions, is based on the convolution
of wavelet-based functions with motor stator currents. These functions are tuned to specific fault frequencies
taking into account motor speed and load torque, thus considering variable operation conditions of the motor.
Based on this technique an automatic system for fault diagnosis is also presented, which is suited for easy
Garcia, A.; Rosero, J.; Cusido, J.; Romeral, L.; Ortega, J.A. IEEE transactions on energy conversion Vol. 25, num. 2, p. 312-318 DOI: 10.1109/TEC.2009.2037922 Data de publicació: 2010-06 Article en revista
This paper presents a novel method to diagnose demagnetization
in permanent-magnet synchronousmotor (PMSM).
Simulations have been performed by 2-D finite-element analysis in
order to determine the current spectrum and the magnetic flux
distribution due to this failure. The diagnostic just based on motor
current signature analysis can be confused by eccentricity failure
because the harmonic content is the same. Moreover, it can
only be applied under stationary conditions. In order to overcome
these drawbacks, a novel method is used based upon the
Hilbert–Huang transform. It represents time-dependent series in a
2-D time–frequency domain by extracting instantaneous frequency
components through an empirical-mode decomposition process.
This tool is applied by running the motor under nonstationary
conditions of velocity. The experimental results show the reliability
and feasibility of the methodology in order to diagnose the demagnetization
of a PMSM.
Navarro, L.; Delgado Prieto, M.; Urresty, J.; Cusido, J.; Romeral, L. IEEE Instrumentation and Measurement Technology Conference p. 1159-1163 DOI: 10.1109/IMTC.2010.5488092 Data de publicació: 2010-05-06 Article en revista
The present work shows a condition monitoring
system applied to electric motors ball bearings. Unlike most of the previous work on this area, which is mainly focused on the
location of single-point defects in bearing components – inner and outer races, cage or ball faults -, this research covers wide
range irregularities which are very often more difficult to analyse. In addition to traditional techniques like vibration and
current signals, high frequency current bearing pulses and acoustic emissions are also analysed. High frequency bearings
current pulses are acquired using motors especially modified. This modification isolates ball bearings from the motor stator
frame, except for a bearing housing single point connected to ground through a proper cable where the pulses signal is measured. A multivariable fuzzy inference analysis approach is presented to get around the diagnosis difficulty.