8 research outputs found
Next generation optical access networks and coexistence with legacy PONs
Nowadays, Fiber-to-the-Home is one of the most promising solutions to provide broadband services in access networks. However, the fiber is inefficiently used as most of the deployed systems are still based on Time Division Multiplexing Passive Optical Networks (TDM-PONs) providing shared transmission capacities up to 2.5 Gb/s down and 1.25 Gb/s up, among multiple users. Research on high-speed electronics and Wavelength Division Multiplexing (WDM) has allowed the emergence of what is known as the second generation PON (NG-PON2), which specify aggregated capacities up to 40 Gb/s, stacking four channels at symmetric data rates of 10 Gb/s each, for residential scenarios. Nevertheless, the capacity per channel is still shared between multiple users due to the use of TDM. Moreover, the optical spectrum efficiency is low because channels are widely spaced (50 to 100 GHz). In addition, the sensitivity, reach and number of users is limited as consequence of using direct detection (DD) systems. In consequence, and due to the increase in bandwidth demands of new multimedia applications, it is necessary to propose solutions that cope with this tendency and, even more important, that can coexist with legacy systems, being one of the major requirements of network operators to guarantee a smooth and non-disruptive technology migration.
In this thesis, a breakthrough technology such as Ultra-Dense WDM (UDWDM) that allows to allocate a large number of channels spaced only by a few GHz is used. This approach consent to envision the concept of Wavelength-to-the-User, where each costumer can be served with dedicated bandwidth links. The key technologies are based on coherent systems, with inherent wavelength selectivity and improved sensitivity compared to DD systems, thanks to the booster action of a tunable local oscillator (LO) laser.
Because of cost is the main constraint in access networks, especially at the customer premises equipment (Optical Network Unit - ONU), in this thesis, a new class of coherent transceivers, based on low-cost direct modulated lasers and simplified receiver schemes, are proposed and experimentally tested. Moreover, the issue of coexistence is investigated through theoretical studies and real-time implementations, demonstrating full compatibility with legacy systems.
Between the proposed solutions, a simple technique to adjust digitally the direct phase modulation of a distributed feedback (DFB) laser is presented to support flexible transmission rates. Next, several multilevel phase modulation formats for achieving higher transmission rates and better spectral efficiency are experimentally compared. Subsequently, the topic of photonic integration is addressed, demonstrating for the first time an 8-ary hybrid amplitude and phase modulated transmitter (Tx), by using a low-cost, small-footprint and energy efficient dual electro-absorption modulated laser (DEML). Finally, two novel proposals, to reduce the complexity of heterodyne and intradyne detection, are provided to face the typical issue of complexity and high-cost of coherent systems. The former explores the possibility of using only one DFB laser as LO and Tx at the ONU. The later demonstrates for the first time, a novel phase time diversity technique alternating phase modulation at each complex component (in-phase - I and quadrature - Q) achieving a 10 Gb/s' transmission with polarization independence.En la actualidad, la Fibra hasta el Hogar es una de las soluciones m谩s prometedoras para proporcionar servicios de banda ancha en las redes de acceso. Sin embargo, la fibra se usa de manera poco eficiente, ya que la mayor铆a de los sistemas implementados todav铆a est谩n basados en redes 贸pticas pasivas de multiplexaci贸n por divisi贸n en el tiempo (TDM-PON) que brindan capacidades de transmisi贸n compartidas entre m煤ltiples usuarios de hasta 2.5 Gb/s y 1.25 Gb/s. La investigaci贸n en electr贸nica de alta velocidad y la multiplexaci贸n por divisi贸n de longitud de onda (WDM) ha permitido el surgimiento de lo hoy se conoce como PON de segunda generaci贸n (NG-PON2), que especifica capacidades agregadas de hasta 40 Gb/s, apilando cuatro canales a velocidades de datos sim茅tricas de 10 Gb/s cada uno, para escenarios residenciales. Sin embargo, la capacidad por canal todav铆a se comparte entre m煤ltiples usuarios debido al uso de TDM. Adem谩s, la eficiencia en el uso del espectro 贸ptico es baja porque los canales est谩n muy separados (50 a 100 GHz). Asimismo, la sensibilidad, el alcance y el n煤mero de usuarios est谩n limitados debido al uso de sistemas de detecci贸n directa. En consecuencia, y debido al aumento de las demandas de ancho de banda de las nuevas aplicaciones multimedia, es necesario proponer soluciones que respondan a esta tendencia y, lo que es m谩s importante, que puedan coexistir con sistemas heredados, siendo uno de los principales requisitos de los operadores de red para garantizar una migraci贸n de tecnolog铆a fluida y sin interrupciones. En esta tesis, se utiliza una tecnolog铆a de vanguardia, como la multiplexaci贸n por divisi贸n ultra densa de longitud de onda (UDWDM) que permite distribuir un gran n煤mero de canales espaciados solo por unos pocos GHz. Este enfoque permite vislumbrar el concepto de longitud de onda para el usuario, donde cada cliente puede usar enlaces de ancho de banda dedicados. Las tecnolog铆as clave est谩n basadas en los sistemas coherentes, con selectividad de longitud de onda inherente y sensibilidad mejorada en comparaci贸n con los sistemas de detecci贸n directa, gracias al efecto de amplificaci贸n 贸ptica de un l谩ser oscilador local (LO) sintonizable. Debido a que el costo es la principal restricci贸n en las redes de acceso, especialmente del equipo en las instalaciones del cliente (unidad de red 贸ptica - ONU), en 茅sta tesis, una nueva clase de transceptores coherentes, basados en l谩seres de bajo coste modulados directamente y esquemas de recepci贸n simplificados, son propuestos y probados experimentalmente. Adem谩s, el problema de la coexistencia es investigado a trav茅s de estudios te贸ricos y experimentos en tiempo real, demostrando compatibilidad total con los sistemas heredados. Entre las soluciones propuestas, se presenta una t茅cnica simple para ajustar digitalmente la modulaci贸n de fase directa de un l谩ser de retroalimentaci贸n distribuida (DFB), y admitir velocidades de transmisi贸n flexibles. Acto seguido, se comparan experimentalmente varios formatos multinivel de modulaci贸n de fase, para lograr tasas de transmisi贸n m谩s altas y una mejor eficiencia espectral. Posteriormente, se aborda el tema de la integraci贸n fot贸nica, demostrando por primera vez un transmisor (Tx) con modulaci贸n h铆brida de fase y amplitud de ocho puntos, mediante el uso de un dispositivo peque帽o, de bajo coste y eficiente energ茅ticamente, como lo es el l谩ser dual de electro-absorci贸n modulada (DEML). Finalmente, se presentan dos propuestas novedosas para reducir la complejidad de la detecci贸n heterodina e intradina, afrontando el problema t铆pico de la complejidad y alto coste de los sistemas coherentes. La primera explora la posibilidad de usar solo un l谩ser DFB en la ONU, como LO y Tx. La segunda, demuestra por primera vez, una nueva t茅cnica de diversidad fase en el tiempo, que alterna la modulaci贸n de fase en cada componente del plano complejo (fase-I y cuadratura-Q) logrando una transmisi贸n de 10 Gb / s / 位 con independencia de polarizaci贸
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Hardware-Software Integrated Silicon Photonic Systems
Fabrication of integrated photonic devices and circuits in a CMOS-compatible process or foundry is the essence of the silicon photonic platform. Optical devices in this platform are enabled by the high index contrast between silicon and silicon on insulator. These devices offer potential benefits when integrated with existing and emerging high performance microelectronics. Integration of silicon photonics with small footprints and power-efficient and high-bandwidth operation has long been cited as a solution to existing issues in high performance interconnects for telecommunications and data communication. Stemming from this historic application in communications, new applications in sensing arrays, biochemistry, and even entertainment continue to grow. However, for many technologies to successfully adopt silicon photonics and reap the perceived benefits, the silicon photonic platform must extend toward development of a full ecosystem. Such extension includes implementation of low cost and robust electronic-photonic packaging techniques for all applications. In an ecosystem implemented with services ranging from device fabrication all the way to packaged products, ease-of-use and ease-of-deployment in systems that require many hardware and software components becomes possible.
With the onset of the Internet of Things (IoT), nearly all technologies鈥攕ensors, compute, communication devices, etc.鈥攑ersist in systems with some level of localized or distributed software interaction. These interactions often require a level of networked communications. For silicon photonics to penetrate technologies comprising IoT, it is advantageous to implement such devices in a hardware-software integrated way. Meaning, all functionalities and interactions related to the silicon photonic devices are well defined in terms of the physicality of the hardware. This hardware is then abstracted into various levels of software as needed in the system. The power of hardware-software integration allows many of the piece-wise demonstrated functionalities of silicon photonics to easily translate to commercial implementation.
This work begins by briefly highlighting the challenges and solutions for transforming existing silicon photonic platforms to a full-fledged silicon photonic ecosystem. The highlighted solutions in development consist of tools for fabrication, testing, subsystem packaging, and system validation. Building off the knowledge of a silicon photonic ecosystem in development, this work continues by demonstrating various levels of hardware-software integration. These are primarily focused on silicon photonic interconnects.
The first hardware-software integration-focused portion of this work explores silicon microring-based devices as a key building block for greater silicon photonic subsystems. The microring鈥檚 sensitivity to thermal fluctuations is identified not as a flaw, but as a tool for functionalization. A logical control system is implemented to mitigate thermal effects that would normally render a microring resonator inoperable. The mechanism to control the microring is extended and abstracted with software programmability to offer wavelength routing as a network primitive. This functionality, available through hardware-software integration, offers the possibility for ubiquitous deployment of such microring devices in future photonic interconnection networks.
The second hardware-software integration-focused portion of this work explores dynamic silicon photonic switching devices and circuits. Specifically, interactions with and implications of high-speed data propagation and link layer control are demonstrated. The characteristics of photonic link setup include transients due to physical layer optical effects, latencies involved with initializing burst mode links, and optical link quality. The impacts on the functionalities and performance offered by photonic devices are explored. An optical network interface platform is devised using FPGAs to encapsulate hardware and software for controlling these characteristics using custom hardware description language, firmware, and software. A basic version of a silicon photonic network controller using FPGAs is used as a tool to demonstrate a highly scalable switch architecture using microring resonators. This architecture would not be possible without some semblance of this controller, combined with advanced electronic-photonic packaging. A more advanced deployment of the network interface platform is used to demonstrate a method for accelerating photonic links using out-of-band arbitration. A first demonstration of this platform is performed on a silicon photonic microring router network. A second demonstration is used to further explore the feasibility of full hardware-software integrated photonic device actuation, link layer control, and out-of-band arbitration. The demonstration is performed on a complete silicon photonic network with both spatial switching and wavelength routing functionalities.
The aforementioned hardware-software integration mechanisms are rigorously tested for data communications applications. Capabilities are shown for very reliable, low latency, and dynamic high-speed data delivery using silicon photonic devices. Applying these mechanisms to complete electronic-photonic packaged subsystems provides a strong path to commercial manifestations of functional silicon photonic devices
Next generation optical access networks and coexistence with legacy PONs
Nowadays, Fiber-to-the-Home is one of the most promising solutions to provide broadband services in access networks. However, the fiber is inefficiently used as most of the deployed systems are still based on Time Division Multiplexing Passive Optical Networks (TDM-PONs) providing shared transmission capacities up to 2.5 Gb/s down and 1.25 Gb/s up, among multiple users. Research on high-speed electronics and Wavelength Division Multiplexing (WDM) has allowed the emergence of what is known as the second generation PON (NG-PON2), which specify aggregated capacities up to 40 Gb/s, stacking four channels at symmetric data rates of 10 Gb/s each, for residential scenarios. Nevertheless, the capacity per channel is still shared between multiple users due to the use of TDM. Moreover, the optical spectrum efficiency is low because channels are widely spaced (50 to 100 GHz). In addition, the sensitivity, reach and number of users is limited as consequence of using direct detection (DD) systems. In consequence, and due to the increase in bandwidth demands of new multimedia applications, it is necessary to propose solutions that cope with this tendency and, even more important, that can coexist with legacy systems, being one of the major requirements of network operators to guarantee a smooth and non-disruptive technology migration.
In this thesis, a breakthrough technology such as Ultra-Dense WDM (UDWDM) that allows to allocate a large number of channels spaced only by a few GHz is used. This approach consent to envision the concept of Wavelength-to-the-User, where each costumer can be served with dedicated bandwidth links. The key technologies are based on coherent systems, with inherent wavelength selectivity and improved sensitivity compared to DD systems, thanks to the booster action of a tunable local oscillator (LO) laser.
Because of cost is the main constraint in access networks, especially at the customer premises equipment (Optical Network Unit - ONU), in this thesis, a new class of coherent transceivers, based on low-cost direct modulated lasers and simplified receiver schemes, are proposed and experimentally tested. Moreover, the issue of coexistence is investigated through theoretical studies and real-time implementations, demonstrating full compatibility with legacy systems.
Between the proposed solutions, a simple technique to adjust digitally the direct phase modulation of a distributed feedback (DFB) laser is presented to support flexible transmission rates. Next, several multilevel phase modulation formats for achieving higher transmission rates and better spectral efficiency are experimentally compared. Subsequently, the topic of photonic integration is addressed, demonstrating for the first time an 8-ary hybrid amplitude and phase modulated transmitter (Tx), by using a low-cost, small-footprint and energy efficient dual electro-absorption modulated laser (DEML). Finally, two novel proposals, to reduce the complexity of heterodyne and intradyne detection, are provided to face the typical issue of complexity and high-cost of coherent systems. The former explores the possibility of using only one DFB laser as LO and Tx at the ONU. The later demonstrates for the first time, a novel phase time diversity technique alternating phase modulation at each complex component (in-phase - I and quadrature - Q) achieving a 10 Gb/s' transmission with polarization independence.En la actualidad, la Fibra hasta el Hogar es una de las soluciones m谩s prometedoras para proporcionar servicios de banda ancha en las redes de acceso. Sin embargo, la fibra se usa de manera poco eficiente, ya que la mayor铆a de los sistemas implementados todav铆a est谩n basados en redes 贸pticas pasivas de multiplexaci贸n por divisi贸n en el tiempo (TDM-PON) que brindan capacidades de transmisi贸n compartidas entre m煤ltiples usuarios de hasta 2.5 Gb/s y 1.25 Gb/s. La investigaci贸n en electr贸nica de alta velocidad y la multiplexaci贸n por divisi贸n de longitud de onda (WDM) ha permitido el surgimiento de lo hoy se conoce como PON de segunda generaci贸n (NG-PON2), que especifica capacidades agregadas de hasta 40 Gb/s, apilando cuatro canales a velocidades de datos sim茅tricas de 10 Gb/s cada uno, para escenarios residenciales. Sin embargo, la capacidad por canal todav铆a se comparte entre m煤ltiples usuarios debido al uso de TDM. Adem谩s, la eficiencia en el uso del espectro 贸ptico es baja porque los canales est谩n muy separados (50 a 100 GHz). Asimismo, la sensibilidad, el alcance y el n煤mero de usuarios est谩n limitados debido al uso de sistemas de detecci贸n directa. En consecuencia, y debido al aumento de las demandas de ancho de banda de las nuevas aplicaciones multimedia, es necesario proponer soluciones que respondan a esta tendencia y, lo que es m谩s importante, que puedan coexistir con sistemas heredados, siendo uno de los principales requisitos de los operadores de red para garantizar una migraci贸n de tecnolog铆a fluida y sin interrupciones. En esta tesis, se utiliza una tecnolog铆a de vanguardia, como la multiplexaci贸n por divisi贸n ultra densa de longitud de onda (UDWDM) que permite distribuir un gran n煤mero de canales espaciados solo por unos pocos GHz. Este enfoque permite vislumbrar el concepto de longitud de onda para el usuario, donde cada cliente puede usar enlaces de ancho de banda dedicados. Las tecnolog铆as clave est谩n basadas en los sistemas coherentes, con selectividad de longitud de onda inherente y sensibilidad mejorada en comparaci贸n con los sistemas de detecci贸n directa, gracias al efecto de amplificaci贸n 贸ptica de un l谩ser oscilador local (LO) sintonizable. Debido a que el costo es la principal restricci贸n en las redes de acceso, especialmente del equipo en las instalaciones del cliente (unidad de red 贸ptica - ONU), en 茅sta tesis, una nueva clase de transceptores coherentes, basados en l谩seres de bajo coste modulados directamente y esquemas de recepci贸n simplificados, son propuestos y probados experimentalmente. Adem谩s, el problema de la coexistencia es investigado a trav茅s de estudios te贸ricos y experimentos en tiempo real, demostrando compatibilidad total con los sistemas heredados. Entre las soluciones propuestas, se presenta una t茅cnica simple para ajustar digitalmente la modulaci贸n de fase directa de un l谩ser de retroalimentaci贸n distribuida (DFB), y admitir velocidades de transmisi贸n flexibles. Acto seguido, se comparan experimentalmente varios formatos multinivel de modulaci贸n de fase, para lograr tasas de transmisi贸n m谩s altas y una mejor eficiencia espectral. Posteriormente, se aborda el tema de la integraci贸n fot贸nica, demostrando por primera vez un transmisor (Tx) con modulaci贸n h铆brida de fase y amplitud de ocho puntos, mediante el uso de un dispositivo peque帽o, de bajo coste y eficiente energ茅ticamente, como lo es el l谩ser dual de electro-absorci贸n modulada (DEML). Finalmente, se presentan dos propuestas novedosas para reducir la complejidad de la detecci贸n heterodina e intradina, afrontando el problema t铆pico de la complejidad y alto coste de los sistemas coherentes. La primera explora la posibilidad de usar solo un l谩ser DFB en la ONU, como LO y Tx. La segunda, demuestra por primera vez, una nueva t茅cnica de diversidad fase en el tiempo, que alterna la modulaci贸n de fase en cada componente del plano complejo (fase-I y cuadratura-Q) logrando una transmisi贸n de 10 Gb / s / 位 con independencia de polarizaci贸nPostprint (published version
Identification and control of diffusive systems applied to charge trapping and thermal space sensors
The work underlying this Thesis, has contributed to the main study and characterization of diffusive systems. The research work has been focused on the analysis of two kind of systems. On the one hand, the dynamics of thermal anemometers has been deeply studied. These sensors detect the wind velocity by measuring the power dissipated of a heated element due to forced convection. The thermal dynamics of different sensor structures have been analyzed and modeled during the Thesis work. On the other hand, we have dealed with microelectromechanical systems (MEMS). The dynamics of charge trapped in the dielectric layer of these systems has also been studied. It is know, that this undesired effect has been associated to diffusion phenomena.
In this Thesis a characterization method based on the technique of Diffusive Representation (DR), for linear and nonlinear time-varying diffusive systems, is presented. This technique allows to describe a system with an arbitrary order state-space model in the frequency domain. The changes in the dynamics of a system over time may come as a result of the own actuation over the device or as a result of an external disturbance. In the wind sensor case, the time variation of the model comes from the wind, which is an external disturbance, whereas in the MEMS case, changes in the actuation voltage generate time-variation in the model.
The state-space models obtained from DR characterization have proven to be able to reproduce and predict the behaviour of the devices under arbitrary excitations. Specifically, in the case of wind sensors, the thermal dynamics of these sensors, under constant temperature operation, has been predicted for different wind velocities using Sliding Mode Controllers. As it has been observed, these controllers also help to understand how the time response of a system, under closed loop, can be accelerated beyond the natural limit imposed by its own thermal circuit if the thermal filter associated to the sensor structure has only one significative time constant.
The experimental corroboration of the thermal analysis is presented with various prototypes of wind sensors for Mars atmosphere. On one side, the time-varying thermal dynamics models of two different prototypes of a spherical 3-dimensional wind sensor, developed by the Micro and Nano Technologies group of the UPC, have been obtained. On the other side, the engineering model prototype of the wind sensor of the REMS (Rover Environmental Monitoring Station) instrument that it is currently on board the Curiosity rover in Mars has been characterized.
For the characterization of the dynamics of the parasitic charge trapped in the dielectric layer of a MEMS device, the experimental validation is obtained through quasi-differential capacitance measurements of a two-parallel plate structure contactless capacitive MEMS.El trabajo que subyace a esta Tesis, ha contribuido principalmente al estudio y la caracterizaci贸n de los sistemas difusivos. El trabajo de investigaci贸n se ha centrado en el an谩lisis de dos tipos de sistemas. Por un lado, la din谩mica de los anem贸metros t茅rmicos ha sido estudiada en profundidad. Estos sensores detectan la velocidad del viento a trav茅s de la medida de la potencia disipada en un elemento caliente debido a la convecci贸n forzada. Durante el trabajo de esta Tesis, se ha analizado y modelado la din谩mica t茅rmica de diferentes sensores . Por otro lado, se han tratado tambi茅n los sistemas microelectromec谩nicos (MEMS). Se ha estudiado la din谩mica de la carga atrapada en la capa diel茅ctrica de estos sistemas. Este fen贸meno lento e indeseado est谩 asociado a fen贸menos de difusi贸n. En esta Tesis se presenta un m茅todo de caracterizaci贸n basado en la t茅cnica de Representaci贸n Difusa (DR), para sistemas difusivos lineales y no lineales que var铆an en el tiempo. Esta t茅cnica permite describir un sistema con un modelo de variables de estado de orden arbitrario en el dominio frecuencial. Los cambios en la din谩mica de un sistema a lo largo del tiempo pueden ser debidos a la propia actuaci贸n sobre el dispositivo o como resultado de una perturbaci贸n externa. En el caso del sensor de viento, la variaci贸n de tiempo del modelo proviene de la propia variaci贸n del viento, la cual es una perturbaci贸n externa, mientras que en el caso de los dispositivos MEMS, los cambios en la tensi贸n de actuaci贸n generan variaciones en el tiempo en el modelo. Los modelos de variables de estado obtenidos a partir de la caracterizaci贸n con Representaci贸n Difusiva tienen la capacidad de reproducir y predecir el comportamiento de dichos dispositivos ante excitaciones arbitrarias. En concreto, en el caso de los sensores de viento, la din谩mica t茅rmica de estos sensores, operando a temperatura constante, se ha predicho para diferentes velocidades de viento, usando la teor铆a de los Sliding Mode Controllers (Controladores de Modo Deslizante). Tal y como se ha observado, estos controladores ayudan tambi茅n a comprender c贸mo la respuesta temporal de un sistema, en lazo cerrado, puede acelerarse m谩s all谩 del l铆mite natural impuesto por su propio circuito t茅rmico si el filtro t茅rmico asociado a la estructura del sensor tiene solo una constante de tiempo significativa. La corroboraci贸n experimental del an谩lisis t茅rmico se presenta con varios prototipos de sensores de viento para la atm贸sfera de Marte. Por un lado, se han obtenido los modelos de la din谩mica t茅rmica variable en el tiempo de dos prototipos diferentes de un sensor de viento 3D esf茅rico, desarrollado por el grupo de Micro y Nano Tecnolog铆as de la UPC. Por otro lado, se ha caracterizado el prototipo de modelo de ingenier铆a del sensor de viento del instrumento REMS (Rover Environmental Monitoring Station) que est谩 actualmente abordo del rover Curiosity en Marte. Para la caracterizaci贸n de la din谩mica de la carga atrapada en la capa diel茅ctrica de un dispositivo MEMS, la validaci贸n experimental se ha obtenido a trav茅s de medidas cuasi-diferenciales de la capacidad de un dispositivo MEMS con estructura de dos placas paralelas.Postprint (published version
Identification and control of diffusive systems applied to charge trapping and thermal space sensors
The work underlying this Thesis, has contributed to the main study and characterization of diffusive systems. The research work has been focused on the analysis of two kind of systems. On the one hand, the dynamics of thermal anemometers has been deeply studied. These sensors detect the wind velocity by measuring the power dissipated of a heated element due to forced convection. The thermal dynamics of different sensor structures have been analyzed and modeled during the Thesis work. On the other hand, we have dealed with microelectromechanical systems (MEMS). The dynamics of charge trapped in the dielectric layer of these systems has also been studied. It is know, that this undesired effect has been associated to diffusion phenomena.
In this Thesis a characterization method based on the technique of Diffusive Representation (DR), for linear and nonlinear time-varying diffusive systems, is presented. This technique allows to describe a system with an arbitrary order state-space model in the frequency domain. The changes in the dynamics of a system over time may come as a result of the own actuation over the device or as a result of an external disturbance. In the wind sensor case, the time variation of the model comes from the wind, which is an external disturbance, whereas in the MEMS case, changes in the actuation voltage generate time-variation in the model.
The state-space models obtained from DR characterization have proven to be able to reproduce and predict the behaviour of the devices under arbitrary excitations. Specifically, in the case of wind sensors, the thermal dynamics of these sensors, under constant temperature operation, has been predicted for different wind velocities using Sliding Mode Controllers. As it has been observed, these controllers also help to understand how the time response of a system, under closed loop, can be accelerated beyond the natural limit imposed by its own thermal circuit if the thermal filter associated to the sensor structure has only one significative time constant.
The experimental corroboration of the thermal analysis is presented with various prototypes of wind sensors for Mars atmosphere. On one side, the time-varying thermal dynamics models of two different prototypes of a spherical 3-dimensional wind sensor, developed by the Micro and Nano Technologies group of the UPC, have been obtained. On the other side, the engineering model prototype of the wind sensor of the REMS (Rover Environmental Monitoring Station) instrument that it is currently on board the Curiosity rover in Mars has been characterized.
For the characterization of the dynamics of the parasitic charge trapped in the dielectric layer of a MEMS device, the experimental validation is obtained through quasi-differential capacitance measurements of a two-parallel plate structure contactless capacitive MEMS.El trabajo que subyace a esta Tesis, ha contribuido principalmente al estudio y la caracterizaci贸n de los sistemas difusivos. El trabajo de investigaci贸n se ha centrado en el an谩lisis de dos tipos de sistemas. Por un lado, la din谩mica de los anem贸metros t茅rmicos ha sido estudiada en profundidad. Estos sensores detectan la velocidad del viento a trav茅s de la medida de la potencia disipada en un elemento caliente debido a la convecci贸n forzada. Durante el trabajo de esta Tesis, se ha analizado y modelado la din谩mica t茅rmica de diferentes sensores . Por otro lado, se han tratado tambi茅n los sistemas microelectromec谩nicos (MEMS). Se ha estudiado la din谩mica de la carga atrapada en la capa diel茅ctrica de estos sistemas. Este fen贸meno lento e indeseado est谩 asociado a fen贸menos de difusi贸n. En esta Tesis se presenta un m茅todo de caracterizaci贸n basado en la t茅cnica de Representaci贸n Difusa (DR), para sistemas difusivos lineales y no lineales que var铆an en el tiempo. Esta t茅cnica permite describir un sistema con un modelo de variables de estado de orden arbitrario en el dominio frecuencial. Los cambios en la din谩mica de un sistema a lo largo del tiempo pueden ser debidos a la propia actuaci贸n sobre el dispositivo o como resultado de una perturbaci贸n externa. En el caso del sensor de viento, la variaci贸n de tiempo del modelo proviene de la propia variaci贸n del viento, la cual es una perturbaci贸n externa, mientras que en el caso de los dispositivos MEMS, los cambios en la tensi贸n de actuaci贸n generan variaciones en el tiempo en el modelo. Los modelos de variables de estado obtenidos a partir de la caracterizaci贸n con Representaci贸n Difusiva tienen la capacidad de reproducir y predecir el comportamiento de dichos dispositivos ante excitaciones arbitrarias. En concreto, en el caso de los sensores de viento, la din谩mica t茅rmica de estos sensores, operando a temperatura constante, se ha predicho para diferentes velocidades de viento, usando la teor铆a de los Sliding Mode Controllers (Controladores de Modo Deslizante). Tal y como se ha observado, estos controladores ayudan tambi茅n a comprender c贸mo la respuesta temporal de un sistema, en lazo cerrado, puede acelerarse m谩s all谩 del l铆mite natural impuesto por su propio circuito t茅rmico si el filtro t茅rmico asociado a la estructura del sensor tiene solo una constante de tiempo significativa. La corroboraci贸n experimental del an谩lisis t茅rmico se presenta con varios prototipos de sensores de viento para la atm贸sfera de Marte. Por un lado, se han obtenido los modelos de la din谩mica t茅rmica variable en el tiempo de dos prototipos diferentes de un sensor de viento 3D esf茅rico, desarrollado por el grupo de Micro y Nano Tecnolog铆as de la UPC. Por otro lado, se ha caracterizado el prototipo de modelo de ingenier铆a del sensor de viento del instrumento REMS (Rover Environmental Monitoring Station) que est谩 actualmente abordo del rover Curiosity en Marte. Para la caracterizaci贸n de la din谩mica de la carga atrapada en la capa diel茅ctrica de un dispositivo MEMS, la validaci贸n experimental se ha obtenido a trav茅s de medidas cuasi-diferenciales de la capacidad de un dispositivo MEMS con estructura de dos placas paralelas
Advanced thermal modelling and management techniques to improve power density in next generation power electronics
This thesis sets out a series of new techniques to improve the thermal management of power electronics. The work is motivated by the increasing impetus to design smaller, more energy efficient electronic power systems for a range of applications, notably electric vehicles. Thermal management is an increasingly important tool which can facilitate improvements in power density through better monitoring and control of system temperatures. This thesis seeks to deliver improvements in implementing this strategy.
A review of the state of the art in thermal management is reported, focussing on temperature measurement, thermal characterisation and system modelling techniques. In addition, novel techniques for arbitrary dissipation control and die temperature measurements in semiconductor devices are presented. A novel analysis of the limitations of low-order thermal models is also described. Improvements and applications of these techniques form the basis of this thesis.
The pseudorandom binary sequence (PRBS) technique for system identification is applied throughout the thesis to characterise thermal systems. A mathematical analysis is provided, together with a novel technique to determine the minimum gain which can be identified by PRBS techniques in the presence of noise. A novel improvement to the PRBS technique for typically ten times more noise resilient measurements is then developed based on mathematical mixing of different frequency PRBS signals. In parallel, a novel technique is formulated to estimate the temperature throughout a multiple device system using digital IIR filters and PRBS thermal characterisation, which achieves errors of 3-5% when demonstrated practically. By combining these techniques, a comprehensive temperature estimation and control methodology is implemented for a multiple device system under active cooling. Finally, the expansion of the proposed methodologies to steady-state die temperature estimation is presented with comparable accuracy to surface temperature measurements, increasing the usefulness of the developed techniques in a practical setting
In Situ Parameter Estimation of a Single-Phase Voltage Source Inverter using Pseudo-Random Impulse Sequence Perturbation
Electrical and Electronic Engineerin
Topical Workshop on Electronics for Particle Physics
The purpose of the workshop was to present results and original concepts for electronics research and development relevant to particle physics experiments as well as accelerator and beam instrumentation at future facilities; to review the status of electronics for the LHC experiments; to identify and encourage common efforts for the development of electronics; and to promote information exchange and collaboration in the relevant engineering and physics communities