EH Performance of an Hybrid Energy Harvester for Autonomous Nodes

This paper reports the Energy Harvesting (EH) performance of a hybrid energy harvester able to collect energy form different energy sources: thermal, solar and electromagnetic. The main block of the system is the quarter-wavelength patch antenna, operating in the Industrial, Scientific and Medical (ISM) frequency band 2.4-2.5 GHz. The antenna has been designed and optimized to support a Thermo-Electric Generator (TEG) and a Solar Cell on its top. Moreover, a rectifier has been designed to work with the antenna and a DC-DC converter has been used to manage the TEG output voltage

Initial Development of an Electrical Power Generator by using Thermoelectric Generator, Focal Lens and Underground Heat Dissipation System

Electrical energy is important in various developments to ensure global stability. However, most electrical energy sources are non-renewable and these sources are expected to be depleted in the near future. In order to solve this problem, research on renewable energy sources are intensified and thermoelectric generator (TEG) is one of the potential solutions. TEG can generate electricity if the there is a temperature difference between the hot end and cold end of its plate and it is widely used in various applications, ranging from high temperature of a steam generator until to the lowest temperature of a human body. The initial development of this work focuses on the electrical power generator design by using focal lens to focus sunlight, a form of renewable energy, on the TEG hot end and also underground heat dissipation system on the cold end to create temperature difference. The initial results showed that the amount of power produced by the system is quite small but reasonable due to the type of TEGs used. However, the heat dissipation system showed a promising development due to its non-dependency on external energy to expel heat from the cold side

Circuit Optimization for Enhancing the Output Power of a Piezoelectric Energy Harvester

In this paper, a new method is proposed for improving a piezoelectric energy harvester’s output power. A piezoelectric vibration energy harvester has an inherent internal capacitance. The new approach adopts inductance to reduce the reactance of the internal capacitance and enhance the output power. To show the practicality of this method, four electrical circuits are investigated numerically and experimentally for a piezoelectric beam energy harvester: Simple Resistive Load, Inductive Load, standard AC-DC, and Inductive AC-DC circuits. An Inductive Load circuit is built by adding an inductor to a Simple Resistive Load circuit, while an Inductive AC-DC circuit is built by adding an inductor to a standard AC-DC circuit. Experimental results indicate that the Inductive Load and the Inductive AC-DC circuits avail the Simple Resistive Load and standard AC-DC circuits respectively. The inductive AC-DC circuit shows a 6.7% increase in the output power compared to the standard AC-DC circuit

Design of efficient microwave power amplifier systems

In the future communication systems, it is of key importance that the transceivers are capable of operating in multiple frequency bands and with complex signals. In this context, the power amplifier is a critical component of the transceiver, since it is responsible for most of the total power consumption in base stations and portable devices. Apart from the power consumption, the design of power amplifier systems must account for multi-band/broadband capabilities, high peak-toaverage power ratio signals and the mismatch effect caused by the various operating conditions. Hence, the design of power amplifier topologies that enhance the total system efficiency and reliability is a challenging task. This PhD dissertation introduces novel power amplifier architectures and solutions for modern communication systems. The contributions of this thesis can be divided in two parts. The first part deals with the study and design of power amplifier systems. It is of major importance that these designs provide linear amplification and operation at multiple frequency bands, which will permit the reduction of the cost and size of the devices. Additionally, we investigate the possibility to harvest the dissipated power from the power amplification process. For the development of the prototypes, lumped-element topologies, transmission line implementation and Substrate Integrated Waveguide (SIW) technology are adopted. In the second part of the thesis, novel matching networks are introduced and their properties are studied. In particular, resistance compression topologies are proposed to overcome the performance degradation associated with the sensitivity of nonlinear devices to environmental changes. These networks can be adopted in modern power amplifier architectures, such as envelope tracking and outphasing energy recovery power amplifier topologies, in order to provide improved performance over a wide range of operating conditions.Es primordial que los transceptores de los futuros sistemas de comunicación sean capaces de operar en múltiples bandas de frecuencia y con señales complejas. En este contexto, el amplificador de potencia es un componente crítico del transceptor dado que su consumo energético supone la mayor parte del consumo tanto de las estaciones base como de los dispositivos móviles. Aparte del consumo energético, los nuevos diseños de sistemas de amplificación de potencia deben considerar aspectos como la capacidad de operar en múltiples bandas o en banda ancha, el uso de señales con alta relación de potencia pico a potencia media (PAPR) y el efecto de desadaptación que aparece bajo las diferentes condiciones de funcionamiento. Por lo tanto, el diseño de nuevas topologías para amplificadores de potencia que mejoren la eficiencia total del sistema y la fiabilidad es una tarea compleja. Esta tesis doctoral presenta nuevas arquitecturas de amplificadores de potencia y soluciones para los sistemas de comunicación modernos. Las contribuciones de esta tesis se pueden dividir en dos partes. La primera parte se centra en el estudio y diseño de sistemas de amplificación de potencia con el fin de proporcionar amplificación lineal y funcionamiento en múltiples bandas de frecuencia, lo que permitirá reducir el coste y tamaño de los dispositivos. Además, se investiga la posibilidad de reutilizar la energía disipada en el proceso de amplificación de potencia. Para el desarrollo de los prototipos, se utilizan topologías hibridas, implementaciones con líneas de transmisión y tecnología de guía de onda integrada en sustrato (SIW). En la segunda parte de la tesis, se proponen redes de adaptación y se estudian sus propiedades. En particular, se proponen topologías de compresión de resistencia para minimizar el efecto que producen en el rendimiento la sensibilidad de los dispositivos no lineales a los cambios ambientales. Estas redes pueden ser utilizadas en arquitecturas modernas de amplificadores de potencia como pueden ser las topologías envelope tracking y outphasing energy recovery con el fin de proporcionar un rendimiento mejorado bajo múltiples condiciones de funcionamiento