Solid State Circuits Technologies

The evolution of solid-state circuit technology has a long history within a relatively short period of time. This technology has lead to the modern information society that connects us and tools, a large market, and many types of products and applications. The solid-state circuit technology continuously evolves via breakthroughs and improvements every year. This book is devoted to review and present novel approaches for some of the main issues involved in this exciting and vigorous technology. The book is composed of 22 chapters, written by authors coming from 30 different institutions located in 12 different countries throughout the Americas, Asia and Europe. Thus, reflecting the wide international contribution to the book. The broad range of subjects presented in the book offers a general overview of the main issues in modern solid-state circuit technology. Furthermore, the book offers an in depth analysis on specific subjects for specialists. We believe the book is of great scientific and educational value for many readers. I am profoundly indebted to the support provided by all of those involved in the work. First and foremost I would like to acknowledge and thank the authors who worked hard and generously agreed to share their results and knowledge. Second I would like to express my gratitude to the Intech team that invited me to edit the book and give me their full support and a fruitful experience while working together to combine this book

高密度・高速動作可能なSTT-MRAMへ向けたp-MTJのスイッチング過渡現象とアレイ設計指針に関する研究

Tohoku University遠藤哲郎課

Piezoelectric and Magnetoelectric Thick Films for Fabricating Power Sources in Wireless Sensor Nodes

In this manuscript, we review the progress made in the synthesis of thick film-based piezoelectric and magnetoelectric structures for harvesting energy from mechanical vibrations and magnetic field. Piezoelectric compositions in the system Pb(Zr,Ti)O3–Pb(Zn1/3Nb2/3)O3 (PZNT) have shown promise for providing enhanced efficiency due to higher energy density and thus form the base of transducers designed for capturing the mechanical energy. Laminate structures of PZNT with magnetostrictive ferrite materials provide large magnitudes of magnetoelectric coupling and are being targeted to capture the stray magnetic field energy. We analyze the models used to predict the performance of the energy harvesters and present a full system description

High quality Nb/Al-AlOx/Nb Josephson junctions : technological development and macroscopic quantum experiments

Diese Arbeit beschreibt die Entwicklung einer Technologie für die Herstellung hochqualitativer sub-µm Nb/Al-AlOx/Nb-Josephson-Kontakte. Mit den dadurch entstandenen Bauteilen wurden verschiedene experimentell zuvor noch nicht beobachtete makroskopische Quanteneffekte nachgewiesen. Weiterhin wurden Nb-basierte Phasen-Qubits entworfen, hergestellt und gemessen, die längere Kohärenzzeiten als vergleichbare Bauelemente aus der Literatur aufweisen

Power Converter of Electric Machines, Renewable Energy Systems, and Transportation

Power converters and electric machines represent essential components in all fields of electrical engineering. In fact, we are heading towards a future where energy will be more and more electrical: electrical vehicles, electrical motors, renewables, storage systems are now widespread. The ongoing energy transition poses new challenges for interfacing and integrating different power systems. The constraints of space, weight, reliability, performance, and autonomy for the electric system have increased the attention of scientific research in order to find more and more appropriate technological solutions. In this context, power converters and electric machines assume a key role in enabling higher performance of electrical power conversion. Consequently, the design and control of power converters and electric machines shall be developed accordingly to the requirements of the specific application, thus leading to more specialized solutions, with the aim of enhancing the reliability, fault tolerance, and flexibility of the next generation power systems

An ADRC-based control strategy for FRT improvement of wind power generation with a doubly-fed induction generator

This paper proposes a second-order active disturbance rejection control (ADRC)-based control strategy with an integrated design of the flux damping method, for the fault ride-through (FRT) improvement in wind power generation systems with a doubly-fed induction generator (DFIG). First, a first principles model of the rotor and grid side converter of DFIG is developed, which is then used to theoretically analyze the system characteristics and show the damage caused to the DFIG system by a grid voltage fault. Then, the flux damping method is used to suppress the rotor current during a fault ride-through. In order to enhance the robustness and effectiveness of the flux damping method under complex working conditions, an ADRC approach is proposed for disturbance attenuation of the DFIG systems. Finally, a comparison of the proposed method with three other control approaches on a 1.5-MV DFIG system benchmark is performed. It is shown that the proposed method can adaptively and effectively improve the system performance during an FRT

Control Aspects for Energy-Efficient and Sensorless AC Motor Drives

This research proposes control methods for improving the energy efficiency and stability of sensorless AC motor drives. The study focuses on induction motors (IMs) and synchronous reluctance motors (SyRMs). Loss-minimizing methods are developed for both IM and SyRM drives. The loss-minimizing control applies dynamic space-vector motor models which take into account hysteresis losses and eddy-current losses as well as the magnetic saturation. The minimum points of the loss function are numerically searched in order to calculate the efficiency-optimal control variable. Magnetic saturation effects can affect the energy optimization more significantly than core-loss parameters. Additionally, flux-angle and rotor-angle estimation methods in sensorless drives are also sensitive to inductance parameters. A saturation model was proposed for SyRMs using explicit power functions. The proposed model takes into account cross saturation and fulfills the reciprocity condition. In order to improve the stability of the sensorless IM drives, especially at low speeds, a gain scheduling method was proposed for a full-order flux observer. The observer gains are selected as functions of the rotor speed estimate in order to improve the damping and robustness of the closed-loop system. The observer is augmented with a stator-resistance adaptation scheme in the low-speed region. In high-speed applications with limited sampling frequency, dynamic performance of the discrete-time approximation of a continuous-time controller can dramatically decrease, and can, in the worst case, even become unstable. A discrete-time current controller was proposed for SyRMs. The current controller is designed based on the exact discrete-time motor model that includes the effects of the zero-order hold and delays. The dynamic performance and robustness are improved, especially at low sampling to fundamental frequency ratios

Short circuit modeling of wind turbine generators

Modeling of wind farms to determine their short circuit contribution in response to faults is a crucial part of system impact studies performed by power utilities. Short circuit calculations are necessary to determine protective relay settings, equipment ratings and to provide data for protection coordination. The plethora of different factors that influence the response of wind farms to short circuits makes short circuit modeling of wind farms an interesting, complex, and challenging task. Low voltage ride through (LVRT) requirements make it necessary for the latest generation of wind generators to be capable of providing reactive power support without disconnecting from the grid during and after voltage sags. If the wind generator must stay connected to the grid, a facility has to be provided to by-pass the high rotor current that occurs during voltage sags and prevent damage of the rotor side power electronic circuits. This is done through crowbar circuits which are of two types, namely active and passive crowbars, based on the power electronic device used in the crowbar triggering circuit. Power electronics-based converters and controls have become an integral part of wind generator systems like the Type 3 doubly fed induction generator based wind generators. The proprietary nature of the design of these power electronics makes it difficult to obtain the necessary information from the manufacturer to model them accurately. Also, the use of power electronic controllers has led to phenomena such as sub-synchronous control interactions (SSCI) in series compensated Type 3 wind farms which are characterized by non-fundamental frequency oscillations. SSCI affects fault current magnitude significantly and is a crucial factor that cannot be ignored while modeling series compensated Type 3 wind farms. These factors have led to disagreement and inconsistencies about which techniques are appropriate for short circuit modeling of wind farms. Fundamental frequency models like voltage behind transient reactance model are incapable of representing the majority of critical wind generator fault characteristics such as sub-synchronous interactions. The Detailed time domain models, though accurate, demand high levels of computation and modeling expertise. Voltage dependent current source modeling based on look up tables are not stand-alone models and provide only a black-box type of solution. The short circuit modeling methodology developed in this research work for representing a series compensated Type 3 wind farm is based on the generalized averaging theory, where the system variables are represented as time varying Fourier coefficients known as dynamic phasors. The modeling technique is also known as dynamic phasor modeling. The Type 3 wind generator has become the most popular type of wind generator, making it an ideal candidate for such a modeling method to be developed. The dynamic phasor model provides a generic model and achieves a middle ground between the conventional electromechanical models and the cumbersome electromagnetic time domain models. The essence of this scheme to model a periodically driven system, such as power converter circuits, is to retain only particular Fourier coefficients based on the behavior of interest of the system under study making it computationally efficient and inclusive of the required frequency components, even if non-fundamental in nature. The capability to model non-fundamental frequency components is critical for representing sub-synchronous interactions. A 450 MW Type 3 wind farm consisting of 150 generator units was modeled using the proposed approach. The method is shown to be highly accurate for representing faults at the point of interconnection of the wind farm to the grid for balanced and unbalanced faults as well as for non-fundamental frequency components present in fault currents during sub-synchronous interactions. Further, the model is shown to be accurate also for different degrees of transmission line compensation and different transformer configurations used in the test system

Sliding mode control in grid-connected wind farms for stability enhancement

Aiming at reducing the rather high percentage of CO2 emissions attributed to the electrical energy production industry, a new generation of power plants has been introduced which produce electricity by using primary energy resources which are said to be renewable, such as wind, solar, geothermal and biomass. This has had not only the benefit of reducing CO2 emissions into the atmosphere to a trickle, by the new power plants but to also encourage a great deal of technological advance in both the manufacturing sector and in research institutions. Wind power is arguably the most advanced form of renewable energy generation today, from the bulk energy production and economic vantages. This doctoral thesis rigorously deals with the analysis, assessment and description of the impact of double-fed variable speed wind turbine on the dynamic behaviour of both, the wind farm itself and its interconnection with the conventional power generation system. Analytical analysis of the results published in the open literature is used as a tool to gain a solid understanding of the dynamic behaviour of power systems with wind generation. The influence of the characteristics of the electrical system and wind turbines or external parameters on stability is assessed using modal analysis. Studies conducted have focused on the analysis of transient stability and small signal stability for the damping of oscillations in power systems and its enhancement. Analysis of small signal stability and transient stability analysis are carried out using modal analysis and dynamic simulations in the time domain. This thesis proposes the implementation of sliding mode control techniques for the DFIG WT converters, both the Machine-Side Converter (MSC) and the Grid-Side Converter (GSC). The proposed control system is assessed on conventional dynamic power systems with wind power generation under different test case scenarios. The newly developed SMC control scheme demonstrates the importance of employing non-linear control algorithms since they yield good operational performances and network support. This is of the utmost important since in power systems with wind power generation is critically important to ensure the robust operation of the whole system with no interaction of controllers. Sliding Mode Control shows to be more robust and exible than the classical controller, opening the door for a more widespread future participation of DFIG-WECS in the damping of power system oscillations. ----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------Con el objetivo de reducir el elevado porcentaje de las emisiones de CO2 atribuidas al sector de la generación de energía eléctrica, se ha introducido una nueva generación de centrales eléctricas cuya fuente primaria de energía es de naturaleza renovable como las eólicas, solares, geotérmicas y de biomasa. Esto no sólo beneficia la reducción de las emisiones de CO2 a la atmósfera sino que también estimula e impulsa el avance tecnológico, tanto en el sector manufacturero como en los centros de investigación. En la actualidad la energía eólica es probablemente la fuente de energía renovable más avanzada, desde la producción de energía hasta las ventajas económicas. La presente Tesis Doctoral se ha centrado en analizar, evaluar y describir rigurosamente el impacto de los aerogeneradores de velocidad variable doblemente alimentados en el comportamiento dinámico tanto del propio sistema eólico como de su interconexión con el sistema síncrono convencional de generación de energía eléctrica. El análisis analítico de los resultados publicados en la literatura es utilizado como herramienta para una mejor comprensión del comportamiento dinámico de los sistemas de potencia con generación eólica. La influencia de las características del sistema eléctrico y de los aerogeneradores o parámetros externos sobre la estabilidad es evaluada empleando análisis modal. Los estudios realizados se han enfocado en el análisis de estabilidad transitoria y de pequeña señal para la evaluación de la amortiguación de oscilaciones en las redes eléctricas de potencia. Análisis de estabilidad de pequeña señal y análisis de estabilidad transitoria son llevados a cabo usando análisis modal y simulaciones dinámicas en el dominio del tiempo. En esta tesis se propone la aplicación de técnicas de control en modo deslizante en los convertidores de los aerogeneradores doblemente alimentados, tanto en el convertidor de la máquina como en el convertidor de la red. El sistema de control propuesto es evaluado en redes dinámicas de generación convencional con generación eólica, considerando diferentes escenarios. El recientemente desarrollado sistema de control CMD demuestra la importancia de implementar algoritmos de control no lineales, ya que producen un buen rendimiento y dan soporte a la red. Esto es sumamente importante ya que en los sistemas de potencia con generación de energía eólica es vital asegurar el funcionamiento eficiente de todo el sistema sin interacción de los controladores. El Control en modo deslizante demuestra ser más robusto y flexible que el controlador cl asico, abriendo la puerta a un futuro con una mayor participación de generación eólica en la amortiguación de las oscilaciones de potencia