Torque Control

This book is the result of inspirations and contributions from many researchers, a collection of 9 works, which are, in majority, focalised around the Direct Torque Control and may be comprised of three sections: different techniques for the control of asynchronous motors and double feed or double star induction machines, oriented approach of recent developments relating to the control of the Permanent Magnet Synchronous Motors, and special controller design and torque control of switched reluctance machine

Design optimization and performance analysis methodology for PMSMs to improve efficiency in hydraulic applications

Pla de Doctorats Industrials de la Generalitat de CatalunyaIn the recent years, water pumping and other hydraulic applications are increasingly demanding motors capable to operate under different working conditions, including variable pressure and volumetric flow demands. Moreover, the technical evolution trend of pumping components is to minimize the size, offering compact and adaptable hydraulic units. Hence, the need to optimize the electric motor part to reduce the volume according this trend, maximizing the efficiency, decreasing material and fabrication costs, reducing noise and improving thermal dissipation have originated the research field of this project. So far different methodologies have been focused on designing electrical machines considering few aspects, such as the rated conditions with some size limitations. In addition, the optimization strategies have been based on single operation conditions, improving multiple aspects but not considering the overall performance of the machine and its influence with the working system. This research changes the design and optimization paradigm, focusing on defining beforehand the desired performance of the electrical machine in relation with the application system. The customization is not limited to an operating point but to the whole performance space, which in this case is the torque-speed area. Thus, the designer has plenty of freedom to study the system, and define the desired motor performance establishing the size, thermal and mechanical limitations from the beginning of the process. Moreover, when designing and optimizing electrical machines, the experimental validation is of major importance. From an industrial scope so far, the testing methodologies are focused on evaluating point by point the electrical machine performance, being a robust and trustable way to measure and validate the electrical machine characteristics. Nevertheless,this method requires a large time to prepare the experimental setup and to evaluate the whole motor performance. For this reason, there is a special interest on improving parameter estimation and performance evaluation techniques for electrical machines to reduce evaluation time, setup complexity and increase the number of physical magnitudes to measure in order to have deeper information. This research also develops methodologies to extend the electrical machine experimental validation providing information to evaluate the motor performance. This doctoral thesis has been developed with a collaboration agreement between UPC and the company MIDTAL TALENTOS S.L. The thesis is included within the Industrial Doctorates program 2018 DI 019 promoted by the Generalitat de Catalunya.En los últimos años, el bombeo de agua, entre otras aplicaciones hidráulicas, exige cada vez más motores capaces de operar en diferentes condiciones de trabajo, incluyendo las demandas variables de presión y caudal volumétrico. Además, la evolución técnica de los componentes de bombeo está cada vez más minimizando el tamaño ofreciendo unidades hidráulicas compactas y adaptables. De ahí la necesidad de optimizar la parte del motor eléctrico para reducir el volumen de acuerdo con esta tendencia, maximizando la eficiencia, disminuyendo los costos de material y fabricación, reduciendo el ruido y mejorando la disipación térmica. Todos estos factores han creado el campo de investigación sobre el cual se desarrolla este proyecto. Hasta ahora las metodologías se han centrado en diseñar las máquinas eléctricas considerando unos pocos aspectos técnicos, como las condiciones nominales con algunas limitaciones de tamaño. Además, las estrategias de optimización se han basado en condiciones de operación única, mejorando múltiples aspectos sin considerar el rendimiento general de la máquina y su influencia en el sistema de trabajo. Esta investigación cambia el paradigma de diseño y optimización centrándose en definir de antemano el rendimiento deseado de la máquina eléctrica en relación con el sistema de aplicación. La personalización no se limita a un punto de funcionamiento sino a todo el espacio de operación, que en este caso se expresa en el espacio par-velocidad. Así, el diseñador tiene libertad para estudiar el sistema, definir el rendimiento deseado del motor estableciendo el tamaño, limitaciones térmicas y mecánicas desde el inicio del proceso. Además, a la hora de diseñar y optimizar máquinas eléctricas, la validación experimental es de gran importancia. En el ámbito industrial hasta ahora, las metodologías de ensayo han sido enfocadas a evaluar punto por punto la máquina eléctrica, siendo una forma robusta y confiable de medir y validar sus características. Sin embargo, este método requiere mucho tiempo para preparar la configuración experimental y evaluar el motor en toda su zona de operación. Por esta razón, existe un interés especial en mejorar la estimación de parámetros y las técnicas de evaluación de la operación de las máquinas eléctricas reduciendo tiempo, complejidad y aumentando el número de magnitudes físicas a medir teniendo más información sobre la máquina. Esta investigación también desarrolla metodologías para extender la validación experimental de la máquina eléctrica proporcionando información para evaluar el rendimiento del motor. Esta tesis doctoral ha sido desarrollada con un convenio de colaboración entre la Universidad Politécnica de Cataluña UPC y la empresa MIDTAL TALENTOS S.L. La tesis se engloba dentro del plan de Doctorados Industriales 2018 DI 019 impulsado por la Generalitat de Catalunya.Postprint (published version

Advanced design methodology for permanent magnet synchronous machines in power applications

Most of the world electrical energy is consumed by electric motors, and then, the improvement in their performance leads to essential savings in the global energy consumption, required to reduce the CO2 emissions. Actually, the policies of governments and institutions are becoming more demanding and the manufacturers are forced to offer more and more optimized products. Moreover, many applications are increasingly demanding high performance in terms of power density, reliability or dynamic response, as in the case of electric vehicle, wind power generation or railway traction. The high energetic content of neodymium magnets causes that the permanent magnet machines (PMSM) are the more attractive option with respect to power density. In addition, thanks to the almost complete elimination of the rotor losses they are the most energetically efficient machines. The PMSM design requires of a multiphysical approach since it comprises electric, magnetic and thermal aspects. In this work, a comprehensive review of the technical literature regarding these machines has been done, and some areas for improvement have been found. Firstly, it is common that the procedure starts from a quite defined machine and just an optimization of a specific part is realized. Moreover, excessive dependence on designer’s experience and knowhow is observed, without giving clear instructions for taking design decisions. Finally, excessive dependence on time consuming FEM models is found. Hence, the main objective of this thesis is to develop and propose an advanced design methodology for PMSM design, characterized by being clear and complete, considering whole the design process and giving criteria and tools for taking decisions which lead to an optimum choice of the final solution. A PMSM design methodology has been proposed that enables the evaluation of large amounts of configurations in an automatic manner, easing to the designer the process of taking the final design decision. To implement this methodology, several tools have been developed and explained in detail: electromagnetic models coupled to thermal models and lumped parameter electromagnetic models. Some important modifications were done in the thermal models taken as a reference in order to consider different cooling conditions. In addition, a basis permeance network model was adapted to the selected machine topology and it was used to demonstrate its suitability to be used in combination with Frozen Permeability technique. Following the proposed design methodology, a 75 kW PMSM prototype was designed and validated at the IK4‐IKERLAN medium voltage laboratory. The obtained results have validated both the proposed design methodology and the developed and employed tools.La mayor parte de la energía eléctrica mundial es consumida en motores eléctricos, por lo que la mejora de sus prestaciones conduce a ahorros en el consumo energético esenciales si se quieren reducir las emisiones de CO2. De hecho, las políticas de gobiernos y asociaciones cada vez son más exigentes, y los diseñadores se ven forzados a lanzar productos cada vez más optimizados. Además, cada vez hay más aplicaciones que son muy exigentes en términos de densidad de potencia, fiabilidad o prestaciones dinámicas, como son el vehículo eléctrico, la generación eólica o la tracción ferroviaria. El altísimo contenido energético de los imanes de neodimio provoca que las máquinas imanes permanentes (PMSM) sean las más atractivas en términos de densidad de potencia. Además, debido a la casi total eliminación de pérdidas en el rotor se convierten en las máquinas más eficientes energéticamente. El diseño de una PMSM requiere de un enfoque multidisciplinar, ya que engloba aspectos eléctricos, magnéticos y térmicos. En este trabajo, se ha realizado una revisión exhaustiva de la literatura técnica publicada hasta la fecha en relación con el diseño de estas máquinas, y se han encontrado ciertos puntos de mejora. En primer lugar, muchas veces se parte de un diseño bastante definido y se optimiza una parte concreta del mismo. Además, se aprecia excesiva dependencia de la experiencia y knowhow del diseñador, sin establecer pautas claras para la toma de decisiones de diseño. Finalmente, dependen excesivamente del temporalmente costoso FEM. Por lo tanto, el objetivo principal de esta tesis es desarrollar una metodología avanzada de diseño de PMSMs que sea clara y completa, abarcando todo el proceso de diseño y aportando criterios y herramientas para la toma de decisiones que conduzcan a una elección óptima de la solución final. Se ha propuesto una metodología de diseño que permite la evaluación de gran cantidad de configuraciones de PMSM de forma automática, facilitando la decisión de diseño final por parte del diseñador. Para la implementación de esta metodología, diversas herramientas han tenido que ser desarrolladas y son explicadas en detalle: modelos analíticos electromagnéticos acoplados con modelos térmicos, y modelos electromagnéticos de parámetros concentrados. Importantes modificaciones fueron realizadas sobre los modelos térmicos adoptados para considerar diferentes refrigeraciones. Además, el circuito electromagnético de parámetros concentrados fue adaptado a la topología seleccionada y demostró su validez para ser utilizado en combinación con la técnica de Frozen Permeability. Siguiendo la metodología propuesta, se ha diseñado y fabricado un prototipo de 75 kW y se ha realizado la validación experimental en el laboratorio de media tensión de IK4‐IKERLAN. Los resultados obtenidos han servido para validar tanto la metodología de diseño como las herramientas empleadas en la misma.Munduko energia elektrikoaren zatirik handiena motor elektrikoetan kontsumitzen da, eta, ondorioz, prestazioak hobetzeak lagundu egiten du kontsumo energetikoan funtsezko aurrezpenak egiten, CO2 igorpenak murriztu nahi badira. Berez, gobernuen eta elkarteen eskakizunak gero eta zorrotzagoak dira, eta diseinatzaileak produktu gero eta optimizatuak atera beharrean daude. Gainera, gero eta aplikazio gehiago daude zorroztasun handia eskatzen dutenak potentzi dentsitateari, fidagarritasunari edo prestazio dinamikoei dagokienez, esaterako, ibilgailu elektrikoan, sorkuntza eolikoan edo tren trakzioan. Neodimiozko imanen eduki energetiko itzelaren ondorioz, iman makina iraunkorrak (PMSM) dira erakargarrienak potentzi dentsitateari dagokionez. Gainera, errotorearen galerak ia guztiz deuseztatzen direnez, energetikoki makinarik eraginkorrenak dira. PMSM bat diseinatzeko diziplina askoko ikuspegia behar da, alderdi elektrikoak, magnetikoak eta termikoak hartzen baititu bere baitan. Lan honetan orain arte honelako makinen diseinuari buruz argitaratutako literatura teknikoaren azterketa zehatza egin da, eta hobetzeko hainbat puntu aurkitu dira. Lehenik eta behin, askotan, abiapuntua nahiko definituta dagoen diseinu bat izaten da, eta egiten dena da horren zati jakin bat optimizatu. Gainera, gehiegizko mendekotasuna egoten da diseinatzailearen esperientzia eta knowhow‐arekiko, diseinuaren inguruko erabakiak hartzeko jarraibide argiak ezarri gabe. Azkenik, mendekotasun handia dago FEMek behin‐behinean duen kostu handiarekiko. Horrenbestez, tesiaren helburu nagusia da PMSMak diseinatzeko metodologia aurreratu bat garatzea, argia eta osatua, diseinuaren prozesu osoa hartuko duena, eta erabakiak hartzeko irizpideak eta tresnak eskainiko dituena, amaierako soluziorik onena aukeratu ahal izateko. Diseinurako proposatu den metodologiarekin PMSMko konfigurazio kopuru handi bat ebaluatu daiteke automatikoki, diseinatzaileari amaierako diseinua erabakitzen laguntzeko. Metodologia inplementatzeko, hainbat tresna garatu behar izan dira, eta horiek zehatz esplikatzen dira: eredu analitiko elektromagnetikoak, eredu termikoekin uztartuta, eta parametro kontzentratuen bidezko eredu elektromagnetikoak. Hautatutako eredu termikoetan aldaketa garrantzitsuak egin behar izan ziren, hozkuntza desberdinak lantzeko. Horrez gain, parametro kontzentratuen zirkuitu elektromagnetikoa hautatutako topologiara egokitu zen, eta bere balioa frogatu zuen, Frozen Permeability teknikarekin konbinatuta erabiltzeko. Proposatutako metodologiari jarraituz, 75 kW‐eko prototipo bat diseinatu eta fabrikatu da, eta balioztapen esperimentala egin da IK4‐IKERLANeko tentsio ertaineko laborategian. Lortutako emaitzek diseinuaren metodologia zein bertan erabilitako tresnak balioztatzeko balio izan dute

Recent Advances in Robust Control

Robust control has been a topic of active research in the last three decades culminating in H_2/H_\infty and \mu design methods followed by research on parametric robustness, initially motivated by Kharitonov's theorem, the extension to non-linear time delay systems, and other more recent methods. The two volumes of Recent Advances in Robust Control give a selective overview of recent theoretical developments and present selected application examples. The volumes comprise 39 contributions covering various theoretical aspects as well as different application areas. The first volume covers selected problems in the theory of robust control and its application to robotic and electromechanical systems. The second volume is dedicated to special topics in robust control and problem specific solutions. Recent Advances in Robust Control will be a valuable reference for those interested in the recent theoretical advances and for researchers working in the broad field of robotics and mechatronics

A Review of Modeling and Diagnostic Techniques for Eccentricity Fault in Electric Machines

Research on the modeling and fault diagnosis of rotor eccentricities has been conducted during the past two decades. A variety of diagnostic theories and methods have been proposed based on different mechanisms, and there are reviews following either one type of electric machines or one type of eccentricity. Nonetheless, the research routes of modeling and diagnosis are common, regardless of machine or eccentricity types. This article tends to review all the possible modeling and diagnostic approaches for all common types of electric machines with eccentricities and provide suggestions on future research roadmap. The paper indicates that a reliable low-cost non-intrusive real-time online visualized diagnostic method is the trend. Observer-based diagnostic strategies are thought promising for the continued research

Sensorless position estimation in fault-tolerant permanent magnet AC motor drives with redundancy.

Safety critical applications are heavily dependent on fault-tolerant motor drives being capable of continuing to operate satisfactorily under faults. This research utilizes a fault-tolerant PMAC motor drive with redundancy involving dual drives to provide parallel redundancy where each drive has electrically, magnetically, thermally and physically independent phases to improve its fault-tolerant capabilities. PMAC motor drives can offer high power and torque densities which are essential in high performance applications, for example, more-electric airplanes. In this thesis, two sensorless algorithms are proposed to estimate the rotor position in a fault-tolerant three-phase surface-mounted sinusoidal PMAC motor drive with redundancy under normal and faulted operating conditions. The key aims are to improve the reliability by eliminating the use of a position sensor which is one of major sources of failures, as well as by offering fault-tolerant position estimation. The algorithms utilize measurements of the winding currents and phase voltages, to compute flux linkage increments without integration, hence producing the predicted position values. Estimation errors due measurements are compensated for by a modified phase-locked loop technique which forces the predicted positions to track the flux linkage increments, finally generating the rotor position estimate. The fault-tolerant three-phase sensorless position estimation method utilizes the measured data from the three phase windings in each drive, consequently obtaining a total of two position estimates. However, the fault-tolerant two-phase sensorless position estimation method uses measurements from pairs of phases and produces three position estimates for each drive. Therefore, six position estimates are available in the dual drive system. In normal operation, all of these position estimates can be averaged to achieve a final rotor angle estimate in both schemes. Under faulted operating conditions, on the other hand, a final position estimate should be achieved by averaging position estimates obtained with measurements from healthy phases since unacceptable estimation errors can be created by making use of measured values from phases with failures. In order to validate the effectiveness of the proposed fault-tolerant sensorless position estimation schemes, the algorithms were tested using both simulated data and offline measured data from an experimental fault-tolerant PMAC motor drive system. In the healthy condition, both techniques presented good performance with acceptable accuracies under low and high steady-state speeds, starting from standstill and step load changes. In addition, they had robustness against parameter variations and measurement errors, as well as the ability to recover quickly from large incorrect initial position information. Under faulted operating conditions such as sensor failures, however, the two-phase sensorless method was more reliable than the threephase sensorless method since it could operate even with a faulty phase.Thesis (Ph.D.) -- University of Adelaide, School of Electrical and Electronic Engineering, 201

Position estimation for PMSMs at any speed using the zero-sequence voltage and modified space vector modulation

Anisotropy-based estimation techniques enable position and speed estimation for synchronous and induction machines down to low speeds and standstill. One possible approach consists of exciting the machine with special pulse patterns and measuring the zero-sequence voltage which requires access to the neutral point of a star-connected machine but can in return enable high signal-to-noise ratios. This thesis focuses in particular on permanent magnet synchronous machines and aims to contribute to the understanding of fundamental relations through a mathematical analysis of the underlying anisotropy information as well as to practical aspects that include initial polarity detection, usable pulse patterns and investigations on certain non-ideal effects which real machines exhibit. Experimentally achieved estimation results using real machines are presented, which demonstrate in particular low noise content and little dependence on rotor speed.Anisotropiebasierte Schätzverfahren ermöglichen Positions- und Drehzahlschätzung für Synchron- und Induktionsmaschinen bis hin zu niedrigen Drehzahlen und Stillstand. Ein möglicher Ansatz besteht darin, die Maschine mit speziellen Pulsmustern anzuregen und die Nullspannung zu messen, was den Zugang zum Sternpunkt einer im Stern verschalteten Maschine erfordert, dafür aber hohe Signal-Rausch-Verhältnisse ermöglichen kann. Diese Arbeit konzentriert sich insbesondere auf Permanentmagnet-Synchronmaschinen und möchte durch eine mathematische Analyse der zugrundeliegenden Anisotropie-Information zum Verständnis grundlegender Zusammenhänge beitragen sowie zu praktischen Aspekten, darunter die Erkennung der anfänglichen Polarität, verwendbare Pulsmuster und Untersuchungen zu bestimmten nicht-idealen Effekten, welche bei realen Maschinen auftreten. Es werden experimentell erzielte Ergebnisse der Schätzung bei realen Maschinen vorgestellt, die insbesondere einen geringen Rauschanteil und eine geringe Abhängigkeit von der Rotordrehzahl aufzeigen

Development of a multidisciplinary and optimized design methodology for surface permanent magnets synchronous machines

Electric energy is one of the supports of modern civilization. In the actual context, the electrical machines are of capital importance since most of power plants, from nuclear plants to wind turbines, need an electrical machine working as a generator. Moreover, it is estimated that nowadays the 65% of the total energy supplied by the grid is consumed by electric motors working in an industrial environment. Electrical machines are complex systems where a great amount of physical phenomena are produced simultaneously; that is why a proper design requires detailed multidisciplinary models. However, most of the design methodologies and tools are only focused on machine electromagnetic performance in order to achieve power, efficiency and mass to volume ratio goals, performing an adequate more than an optimized design. In the best cases, the features related with other physical domains are taken into account through figures or merit or rules of the thumb based on designer particular experience (e.g. thermal sizing); or even they are treated as an afterthought if needed (typical case of the machine vibro-acoustic performance). These approaches are only suitable for very well-known applications where machine features are perfectly known and characterized. However, these methodologies are unsystematic by nature so they have serious difficulties in order to extrapolate the obtained results to a new set of specifications or to more challenging applications where not only electromagnetic criteria but other physical domains, such as vibro-acoustic, should be taken into account. More precisely, since the advent of neodymium iron boron (NdFeB) magnets, permanent magnets synchronous machines (PMSM) has become a suitable option both in industrial and domestic applications such as aircraft industry, elevation, electric vehicle or power generation. Due to their attractive features (e.g. high efficiency, compactness and power density) PMSMs are an emerging technology and an attractive field of study, as it is highlighted by the great amount of publications devoted to that topic in the last years. Therefore, the thesis main goal is the development of a pioneering PMSM design methodology based on a holistic, multidisciplinary and optimized approach. Moreover, this proposed methodology takes into account not only the electromagnetic and thermal conventional aspects but also the machine vibro-acoustic behaviour. In order to fulfil this aim, a complete multiphysical analytical model has been carried out, including a detailed study of the electromagnetic, thermal and vibro-acoustics PMSM features, paying a special attention to these physical domains interactions. The developed models have been used in order to implement a PMSM design optimized methodology based on an innovative heuristic algorithm labelled Direct Multisearch (DMS). In order to validate the physical models, a 75 kW PMSM prototype (IkerMAQ) has been designed and built. A huge amount of tests were carried out and the analytical models have been exhaustively validated, including electromagnetic, thermal and vibro-acoustic domains

NOVEL METHODS FOR PERMANENT MAGNET DEMAGNETIZATION DETECTION IN PERMANENT MAGNET SYNCHRONOUS MACHINES

Monitoring and detecting PM flux linkage is important to maintain a stable permanent magnet synchronous motor (PMSM) operation. The key problems that need to be solved at this stage are to: 1) establish a demagnetization magnetic flux model that takes into account the influence of various nonlinear and complex factors to reveal the demagnetization mechanism; 2) explore the relationship between different factors and demagnetizing magnetic field, to detect the demagnetization in the early stage; and 3) propose post-demagnetization measures. This thesis investigates permanent magnet (PM) demagnetization detection for PMSM machines to achieve high-performance and reliable machine drive for practical industrial and consumer applications. In this thesis, theoretical analysis, numerical calculation as well as experimental investigations are carried out to systematically study the demagnetization detection mechanism and post-demagnetization measures for permanent magnet synchronous motors. At first a flux based acoustic noise model is proposed to analyze online PM demagnetization detection by using a back propagation neural network (BPNN) with acoustic noise data. In this method, the PM demagnetization is detected by means of comparing the measured acoustic signal of PMSM with an acoustic signal library of seven acoustical indicators. Then torque ripple is chosen for online PM demagnetization diagnosis by using continuous wavelet transforms (CWT) and Grey System Theory (GST). This model is able to reveal the relationship between torque variation and PM electromagnetic interferences. After demagnetization being detected, a current regulation strategy is proposed to minimize the torque ripples induced by PM demagnetization. Next, in order to compare the demagnetization detection accuracy, different data mining techniques, Vold-Kalman filtering order tracking (VKF-OT) and dynamic Bayesian network (DBN) based detection approach is applied to real-time PM flux monitoring through torque ripple again. VKF-OT is introduced to track the order of torque ripple of PMSM running in transient state. Lastly, the combination of acoustic noise and torque is investigated for demagnetization detection by using multi-sensor information fusion to improve the system redundancy and accuracy. Bayesian network based multi-sensor information fusion is then proposed to detect the demagnetization ratio from the extracted features. During the analysis of demagnetization detection methods, the proposed PM detection approaches both form torque ripple and acoustic noise are extensively evaluated on a laboratory PM machine drive system under different speeds, load conditions, and temperatures