Academic literature on the topic 'Frequency up-converter'

With the rise of wireless sensor networks and the internet of things, many sensors are being developed to help us monitor our environment. Sensor applications from marine animal tracking to implantable healthcare monitoring require small and non-invasive methods of powering, for which purpose traditional batteries are considered too bulky and unreasonable. If appropriately designed, energy harvesting devices can be a viable solution. Solar and wind energy are good candidates of power but require constant exposure to their sources, which may not be feasible for in-vivo and underwater applications. Mechanical energy, however, is available underwater (the motion of the waves) and inside our bodies (the beating of the heart). These vibrations are normally low in frequency and amplitude, thus resulting in a low voltage once converted into electrical signals using conventional mechanical harvesters. These mechanical harvesters also suffer from narrow bandwidth, which limits their efficient operation to a small range of frequencies. Thus, there is a need for a mechanical energy harvester to convert mechanical energy into electrical energy with enhanced output voltage and for a wide range of frequencies. In this thesis, a new mechanical harvester is introduced, and two different methods of rectifying it are investigated. The designed harvester enhances the output voltage and extends the bandwidth of operation using a mechanical frequency up-convertor. This is implemented using magnetic forces to convert low-frequency vibrations to high-frequency pulses with the help of a piezoelectric material to generate high output voltage. The results show a 48.9% increase in the output voltage at 12.2Hz at an acceleration of 1.0g, and a bandwidth increase from 0.23Hz to 11.4Hz. For the rectification, mechanical rectifiers are discussed, which would obviate the need for electrical rectification, thus preventing the losses normally caused by the threshold voltage of electronics. Two designs of mechanical rectifiers are investigated and implemented on the frequency up-converter: a static rectifier and a rotating rectifier. The results show a voltage rectification, which required a sacrifice in the bandwidth and boosted voltage.

碩士<br>逢甲大學<br>電子工程所<br>92<br>Abstract For extending usage of battery, it is imperative to reduce the supply voltage and the power consumption. Most of the Pulse-Frequency- Modulation (PFM) step-up converter has no short circuit protection mechanism. In this paper, a PFM DC/DC step-up converter is designed to include the short circuit protection function. The PFM DC/DC step-up converter can be started at as low as 0.9 volt and its operating voltage is 1.9 volt. In the PFM DC/DC converter, I will focus on the design of the comparator, the control of the oscillator, the precise reference current source, and the accurate reference voltage. Furthermore, it includes a soft-start mechanism to avoid higher current. This converter is manufactured by tsmc 0.35 CMOS process and the operating temperature range is from -20∘to 90∘.

碩士<br>國立交通大學<br>電信研究所<br>85<br>In this report, we present a frequency doubler which doubles frequency from8 GHz to 16 GHz for the phase shift array application and a Ku-Band up-converter for mobile satellite communications. Both of them are fabricated by hybrid-MIC technique. The active device of the frequency doubler is a high electron mobility transistor (HEMT) biased at class B. It doubles frequency from 8 GHz to 16 GHz.and has maximum conversion gain 4.17 dB at input 8.4 GHz; 0 dB conversion gain bandwidth is 750 MHz from 7.96-8.64GHz and Carrier to noise ratio (CNR) is 6dB. The rejection of fundamental and 3rd harmonic are greater than 33dBc and 35 dBc,respectively. The area occupied by the doubler is 30mm*40mm.The Ku-Band up- converter includes two modules. One is the signal-ended resistive mixer. The other is the Ku-Band frequency synthesizer developed by Ting. The up-converter converts IF (0.9 GHz~1.4 GHz) to RF (14.1 GHz~14.6 GHz) with LO 13.2GHz. The maximum conversion loss is 9.6dB. The RF output power is greater than 0 dBm when IF input power greater than 7 dBm. It also achieved LO rejection>20 dBc and 2IF+LO rejection>22.5 dBc. The phase-locked frequency has a bandwidth from 13.160 GHz to 13.208 GHz.

碩士<br>輔仁大學<br>電子工程學系<br>94<br>In this thesis, we investigate a novel architecture of multi-phase digital pulse-width modulation (DPWM) power regulator based on fully table look-up approach for high-frequency switching converters. The regulator comprise a comparator, a PID compensator with look-up table and multi-phase DPWM. The look-up tables can increase the respond time of the high-frequency converter. The multi-phase DPWM can reduce the power consumption for high-frequency converter. The proposed architecture has been validated with simulation and implement results.

This thesis introduces a new photovoltaic (PV) system architecture employing low voltage parallel-connected PV panels interfaced to a high voltage regulated DC bus of a three-phase grid-tied inverter. The concept provides several improvements over existing technologies in terms of cost, safety, reliability, and modularity. A novel resonant mode DC-DC boost converter topology is proposed to enable the PV modules to deliver power to the fixed DC bus. The topology offers high step-up capabilities and a nearly constant efficiency over a wide operating range. A reduced sensor maximum power point tracking (MPPT) controller is developed for the converter to maximize energy harvesting of the PV panels. The reduced sensor algorithm can be generally applied to the class of converters employing pulse frequency modulation control. A ZigBee wireless communication system is implemented to provide advanced control, monitoring and protection features. A testbench for a low cost 500 $W$ smart microconverter is designed and implemented, demonstrating the viability of the system architecture.

It is known that the use of Photovoltaic Water Pumping Systems (PVWPS) is a solution to supply water to populations living in arid and remote regions. But there are still problems regarding costs and market availability of PVWPS. These systems are usually sold as closed kits and with solar energy dedicated equipment. This situation makes it difficult to replace damaged equipment for other that would be available on the market. Also, solar dedicated equipment are more expensive than the general-purpose ones. Another issue is the oversizing of the PV panel in terms of power, when installing low power PVWPS that employ conventional AC motor-pumps. The oversizing occurs in order to achieve the voltage requirements of these water pumps. With the aim of solving the problems mentioned above, this work proposes four innovative solutions for low power PVWPS. The proposed solutions are for installations up to 750W (1HP); employ a maximum of 4 photovoltaic modules; are composed of standard frequency converters and AC motor-pumps. Also, a simple and cost-effective DC-DC voltage step-up converter was conceived to be a part of the suggested PVWPS. It was designed and tested a 750W DC-DC step-up converter with a static gain of 3.44. One of the proposed solutions for low power PVWPS employing the designed DC-DC step-up converter was tested in a laboratory environment and successfully validated. The system was tested under distinct weather conditions and showed promising results. It was verified that is possible to conceive a PVWPS based on standard frequency converters and other conventional components. The present work was made in cooperation with the company VALLED. The goal was to work together with the company in order to develop a modular, reliable, robust and cost effective solution.<br>Sabe-se que o uso de sistemas fotovoltaicos de bombeamento de água (SFVBA) vieram como uma solução para fornecer água a populações que vivem em regiões áridas e remotas. No entanto, ainda existem problemas em relação aos custos e disponibilidade no mercado dos SFVBA. Esses sistemas geralmente são vendidos como conjuntos fechados e com equipamentos dedicados à energia solar. Essa situação dificulta a substituição de equipamentos danificados por outros que estariam disponíveis no mercado. Além disso, os equipamentos dedicados a uso com energia solar são mais caros que os de uso geral. Outra questão é o superdimensionamento do painel fotovoltaico em termos de potência, ao instalar SFVBA de baixa potência que empregam motobombas CA convencionais. O sobredimensionamento ocorre para que se atinjam os requisitos de tensão dessas bombas de água. Para solucionar os problemas mencionados acima, este trabalho propõe quatro soluções inovadoras para SFVBA de baixa potência. As soluções propostas são para instalações de até 750W (1HP); empregam no máximo 4 módulos fotovoltaicos; são compostas por conversores de frequência padrão e motobombas CA. Além disso, para compor os SFVBA sugeridos, um conversor CC-CC elevador de tensão com estrutura simples e econômica foi concebido. Foi projetado e testado um conversor CC-CC elevador de tensão de 750W com um ganho estático de 3,44. Uma das soluções propostas para SFVBA de baixa potência empregando o conversor CC-CC projetado foi testada em um ambiente de laboratório e validada com sucesso. O sistema foi testado sob condições climáticas distintas e mostrou resultados promissores. Verificou-se que é possível conceber um PVWPS baseado em conversores de frequência de uso geral e outros componentes convencionais. O presente trabalho foi realizado em cooperação com a empresa VALLED. O objetivo era trabalhar em conjunto com a empresa para desenvolver uma solução modular, confiável, robusta e econômica.