Design and Analysis of Fractional-Slot Concentrated-Winding Multiphase Fault-Tolerant Permanent Magnet Synchronous Machines.
In the last decades, the use of permanent magnet machine drives has experienced a sustained growth owing to their high efficiency and power density figures and due to their inherent suitability for direct-driven applications. However, and despite being highly reliable, the fact that the excitation f...
| Main Authors: | , , |
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| Format: | info:eu-repo/semantics/doctoralThesis |
| Language: | eng |
| Published: |
Servicio de Publicaciones. Universidad de Navarra.
2015
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| Subjects: | |
| Online Access: | https://hdl.handle.net/10171/37684 |
| _version_ | 1793400522286301184 |
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| author | Prieto-Rocandio, B. (Borja) Martínez-Iturralde-Maiza, M. (Miguel) Elósegui-Simón, I. (Ibón) |
| author_facet | Prieto-Rocandio, B. (Borja) Martínez-Iturralde-Maiza, M. (Miguel) Elósegui-Simón, I. (Ibón) |
| author_sort | Prieto-Rocandio, B. (Borja) |
| collection | DSpace |
| description | In the last decades, the use of permanent magnet machine drives has experienced a sustained growth owing to their high efficiency and power density figures and due to their inherent suitability for direct-driven applications. However, and despite being highly reliable, the fact that the excitation field in a permanent magnet machine cannot be turned off at will has made engineers reluctant to employ these drives in safety critical applications in the past. Various techniques have been proposed in the related literature to grant fault-tolerance to a permanent magnet machine drive.
This thesis starts by reviewing previous work on the matter and by analyzing the different fault-tolerant approaches. After the various methods are briefly discussed, a comparison among the distinct techniques is established, from which the approach of splitting the drive in multiple independent phases emerges as one the most promising design procedures. This requires that the drive is designed to provide the maximum possible magnetic, electrical, thermal and physical isolation between phases. In order to limit the high magnitude currents arising from a short-circuit fault, a further requirement is that the permanent magnet machine is designed to have a high enough phase self-inductance. The previous requisites are naturally met in permanent magnet machines making use of fractional-slot concentrated-windings. Additionally, multiphase systems have shown to provide a number of advantages over the traditional three-phase systems; specially regarding fault-tolerance and the attainable level of performance after a fault. Owing to the aforementioned reasons, this thesis focuses on the design and analysis of fractional-slot concentrated-winding multiphase fault-tolerant permanent magnet synchronous machines.
Following the review on fault-tolerant permanent magnet drive systems, the design principles that allow to select the most appropriate winding arrangements for fractional-slot concentrated-winding multiphase machines are reviewed. From the research conducted, it is found out that the traditionally proposed rules to select the most adequate configurations are restricted to odd phase number machines or to specific winding configurations. In order to fill this gap, an analytical procedure to evaluate the merits of different winding configurations in terms of magnetic isolation and regardless of the geometry of the machine is established.
A design methodology incorporating the previous winding selection criteria is proposed. Based on this methodology, a five-phase fault-tolerant machine prototype is designed and manufactured. The design process for the prototype, including the analysis of the required specifications and design constraints, is thoroughly discussed.
Next, an analytical drive model suitable for fault analysis is developed. The model serves as a tool to predict the behavior of the designed machine under different fault conditions and to test post-fault remedial strategies. Specifically, the post-fault operation under winding open-circuit faults, terminal short-circuit faults and transistor open and short-circuit faults is investigated.
For the previous fault scenarios, modified control strategies that allow to improve the post-fault performance of AC machine drives are proposed. In particular, a unified approach to compute suitable current references for winding open-circuit and terminal short-circuit faults is derived. The method, aimed at minimizing the stator copper losses while preserving the main harmonic of the air-gap magnetomotive force, is general and valid for any phase number drive and different supply conditions. Experimental tests demonstrate the intrinsic fault-tolerant capability of the prototype machine and the adequacy of the proposed modified control strategies in reducing the parasitic effects arising from the different fault conditions. Furthermore, by adopting the proposed remedial actions, it is possible to operate the machine drive under fault scenarios for which the system previously became unstable. |
| format | info:eu-repo/semantics/doctoralThesis |
| id | oai:dadun.unav.edu:10171-37684 |
| institution | Universidad de Navarra |
| language | eng |
| publishDate | 2015 |
| publisher | Servicio de Publicaciones. Universidad de Navarra. |
| record_format | dspace |
| spelling | oai:dadun.unav.edu:10171-376842022-02-07T11:20:43Z Design and Analysis of Fractional-Slot Concentrated-Winding Multiphase Fault-Tolerant Permanent Magnet Synchronous Machines. Prieto-Rocandio, B. (Borja) Martínez-Iturralde-Maiza, M. (Miguel) Elósegui-Simón, I. (Ibón) Electrical machines. Electric drives. Permanent magnet. Multiphase. Fractional slot. Concentrated winding. In the last decades, the use of permanent magnet machine drives has experienced a sustained growth owing to their high efficiency and power density figures and due to their inherent suitability for direct-driven applications. However, and despite being highly reliable, the fact that the excitation field in a permanent magnet machine cannot be turned off at will has made engineers reluctant to employ these drives in safety critical applications in the past. Various techniques have been proposed in the related literature to grant fault-tolerance to a permanent magnet machine drive. This thesis starts by reviewing previous work on the matter and by analyzing the different fault-tolerant approaches. After the various methods are briefly discussed, a comparison among the distinct techniques is established, from which the approach of splitting the drive in multiple independent phases emerges as one the most promising design procedures. This requires that the drive is designed to provide the maximum possible magnetic, electrical, thermal and physical isolation between phases. In order to limit the high magnitude currents arising from a short-circuit fault, a further requirement is that the permanent magnet machine is designed to have a high enough phase self-inductance. The previous requisites are naturally met in permanent magnet machines making use of fractional-slot concentrated-windings. Additionally, multiphase systems have shown to provide a number of advantages over the traditional three-phase systems; specially regarding fault-tolerance and the attainable level of performance after a fault. Owing to the aforementioned reasons, this thesis focuses on the design and analysis of fractional-slot concentrated-winding multiphase fault-tolerant permanent magnet synchronous machines. Following the review on fault-tolerant permanent magnet drive systems, the design principles that allow to select the most appropriate winding arrangements for fractional-slot concentrated-winding multiphase machines are reviewed. From the research conducted, it is found out that the traditionally proposed rules to select the most adequate configurations are restricted to odd phase number machines or to specific winding configurations. In order to fill this gap, an analytical procedure to evaluate the merits of different winding configurations in terms of magnetic isolation and regardless of the geometry of the machine is established. A design methodology incorporating the previous winding selection criteria is proposed. Based on this methodology, a five-phase fault-tolerant machine prototype is designed and manufactured. The design process for the prototype, including the analysis of the required specifications and design constraints, is thoroughly discussed. Next, an analytical drive model suitable for fault analysis is developed. The model serves as a tool to predict the behavior of the designed machine under different fault conditions and to test post-fault remedial strategies. Specifically, the post-fault operation under winding open-circuit faults, terminal short-circuit faults and transistor open and short-circuit faults is investigated. For the previous fault scenarios, modified control strategies that allow to improve the post-fault performance of AC machine drives are proposed. In particular, a unified approach to compute suitable current references for winding open-circuit and terminal short-circuit faults is derived. The method, aimed at minimizing the stator copper losses while preserving the main harmonic of the air-gap magnetomotive force, is general and valid for any phase number drive and different supply conditions. Experimental tests demonstrate the intrinsic fault-tolerant capability of the prototype machine and the adequacy of the proposed modified control strategies in reducing the parasitic effects arising from the different fault conditions. Furthermore, by adopting the proposed remedial actions, it is possible to operate the machine drive under fault scenarios for which the system previously became unstable. En las últimas décadas, las máquinas de imanes permanentes vienen experimentado un uso creciente debido a las numerosas ventajas que ofrecen respecto a otros tipos de máquinas eléctricas. Sin embargo, la imposibilidad de anular el campo de excitación en estas máquinas ha limitado su uso en aplicaciones de seguridad crítica. Esta tesis comienza analizando las diferentes técnicas propuestas en la bibliografía para dotar de tolerancia a fallos a los accionamientos basados en máquinas de imanes. Tras revisar los diferentes enfoques, se establece una comparativa entre los mismos en términos de coste, complejidad y desempeño tras el fallo. De entre las estrategias consideradas, el método de dividir el accionamiento en múltiples fases independientes surge como uno de los enfoques más prometedores. Ello requiere que el accionamiento sea diseñado para lograr la máxima separación magnética, eléctrica, térmica y física entre las distintas fases. Un requerimiento adicional para lograr la tolerancia a fallos es que la auto-inductancia por fase sea elevada para limitar las corrientes de fallo en caso de cortocircuito. Estos requerimientos se cumplen de forma natural al emplear devanados concentrados fraccionarios. Adicionalmente, los sistemas multifásicos han demostrado dar lugar a una serie de ventajas respecto de los sistemas trifásicos tradicionales; especialmente en lo que se refiere a la tolerancia a fallos y a las prestaciones que se pueden obtener tras un fallo eléctrico. Por todo lo anterior, esta tesis se centra en el diseño y análisis de máquinas síncronas de imanes permanentes tolerantes a fallos multifásicas con devanados concentrados fraccionarios. Tras el estudio inicial, se revisan los principios que permiten escoger las topologías de devanado más adecuadas para el diseño de maquinas tolerantes a fallos con devanados concentrados fraccionarios. Los métodos tradicionalmente propuestos están restringidos a máquinas con un número impar de fases o a configuraciones específicas de devanado. Con el fin de cubrir esta carencia, se desarrolla un método analítico que permite evaluar los méritos de las diferentes configuraciones de devanado posibles independientemente de la geometría de la máquina y escoger así la topología más adecuada para aplicaciones tolerantes a fallos. A continuación, se desarrolla una metodología de diseño de máquinas de imanes tolerantes a fallos. Basándose en la misma, se diseña y fabrica un prototipo de máquina síncrona pentafásica. El proceso completo de diseño, incluyendo el análisis de las especificaciones y las restricciones impuestas, es descrito con amplio detalle. Una serie de ensayos experimentales confirman la tolerancia a fallos intrínseca del prototipo desarrollado y la idoneidad de la metodología de diseño desarrollada. Adicionalmente, se desarrolla un modelo analítico que permite analizar el comportamiento del accionamiento diseñado ante diferentes fallos y evaluar diferentes estrategias correctivas tras los mismos. Específicamente, se investigan los modos de fallo consistentes en fallos de circuito abierto en devanados, fallos de cortocircuito entre terminales y fallos en los dispositivos semiconductores del inversor. Para los citados modos de fallo, se proponen estrategias de control modificadas que permiten mitigar las consecuencias negativas de los mismos. Particularmente, se deriva una metodología general para calcular las corrientes de referencia más adecuadas para fallos de cortocircuito y/o circuito abierto. El método, orientado a minimizar las pérdidas en el cobre mientras se mantiene el harmónico principal de la fuerza magnetomotriz en el entrehierro, es general y valido para cualquier número de fases y diferentes topologías de convertidor. Una serie de ensayos experimentales demuestran la idoneidad de las estrategias de control post-fallo propuestas, que permiten reducir las consecuencias negativas de los fallos y operar el accionamiento en condiciones para las cuales el sistema previamente se volvía inestable. 2015-02-26T08:48:49Z 2015-02-26T08:48:49Z 2015 2015-01-30 info:eu-repo/semantics/doctoralThesis https://hdl.handle.net/10171/37684 eng info:eu-repo/semantics/openAccess application/pdf Servicio de Publicaciones. Universidad de Navarra. |
| spellingShingle | Electrical machines. Electric drives. Permanent magnet. Multiphase. Fractional slot. Concentrated winding. Prieto-Rocandio, B. (Borja) Martínez-Iturralde-Maiza, M. (Miguel) Elósegui-Simón, I. (Ibón) Design and Analysis of Fractional-Slot Concentrated-Winding Multiphase Fault-Tolerant Permanent Magnet Synchronous Machines. |
| title | Design and Analysis of Fractional-Slot Concentrated-Winding Multiphase Fault-Tolerant Permanent Magnet Synchronous Machines. |
| title_full | Design and Analysis of Fractional-Slot Concentrated-Winding Multiphase Fault-Tolerant Permanent Magnet Synchronous Machines. |
| title_fullStr | Design and Analysis of Fractional-Slot Concentrated-Winding Multiphase Fault-Tolerant Permanent Magnet Synchronous Machines. |
| title_full_unstemmed | Design and Analysis of Fractional-Slot Concentrated-Winding Multiphase Fault-Tolerant Permanent Magnet Synchronous Machines. |
| title_short | Design and Analysis of Fractional-Slot Concentrated-Winding Multiphase Fault-Tolerant Permanent Magnet Synchronous Machines. |
| title_sort | design and analysis of fractional-slot concentrated-winding multiphase fault-tolerant permanent magnet synchronous machines. |
| topic | Electrical machines. Electric drives. Permanent magnet. Multiphase. Fractional slot. Concentrated winding. |
| url | https://hdl.handle.net/10171/37684 |
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