Self-powered Sensor Monitoring System in Industrial Internet of Things using Off-resonance Piezoelectric Energy Harvesting Techniques by Jae Yong Cho -Dissertation for the degree of Doctor of Philosophy-Graduate School of Hanyang University-

 Dissertation for the degree of Doctor of Philosophy Self-powered Sensor Monitoring System in Industrial Internet of Things using Off-resonance Piezoelectric Energy Harvesting Techniques 

by Jae Yong Cho

 Graduate School of Hanyang University February 2019 

Department of Electrical Engineering Graduate School of Hanyang University 

 ABSTRACT 

 The main keyword in the era of the fourth industrial revolution is IIoT (Industrial Internet of Things) that enables the interactive network between devices, vehicles, home appliances, and other items embedded with electronics, software, sensors, actuators and etc. To realize IIoT world, there are key technologies; sensors, microcontroller, connectivity, and energy management. Especially, in terms of energy management, many researches have been carried out about self-powering, a battery-less device from energy harvesting. At the center, there is piezoelectric energy harvesting technology, which converts mechanical energy into electrical energy. Lots of researches about piezoelectric energy harvesting have been carried about because piezoelectric material has relatively high power density and is easily applicable to various infrastructures like road, building, and factory close to our daily lives. Ultimately, the goal of this technology is heading for energy saving and simple installation of sensors used for monitoring structural condition without inconveniences such as the replacement of the batteries and the complexity of the cables. In this dissertation, the research about design and fabrication of off-resonance type piezoelectric energy harvesting systems for IIoT sensor was discussed. Because the actual frequency environment in a real field is not geared to resonant frequencies, previous piezoelectric energy harvesting systems were difficult to harvest ambient energy efficiently. We developed the techniques for harvesting energy efficiently through new structures of off-resonance piezoelectric energy harvesters according to various frequency environment. As the final step, the demonstration study was conducted to illustrate IIoT platform as V2I (Vehicle to Infrastructure) system from the piezoelectric energy harvesting techniques. The developed harvester was fabricated and installed on the highway (Yeoju-si, Gyeonggi-do, South Korea). As a result, self-powered temperature sensor monitoring system was constructed using the energy harvester to be able to operate wireless temperature sensor (eZ430-RF2500, Texas Instruments, USA) without battery. Finally, the system was established to inform a driver of the freezing condition on the road in advance as V2I system. First, the design and fabrication of the resonance dependent type energy harvester were conducted. We have developed the piezoelectric energy harvester using wind that is dependent on the resonant frequency, which is a key component of piezoelectric power generation. The experiment result showed that the difference in power generation characteristics when and when not at resonant frequencies makes difficult for the energy harvester to be applied to actual industrial environments where frequencies vary. Finally, it is essential to develop energy harvesters considering these diverse frequency environments. Second, the studies of energy harvesters optimized for different types of frequency environments in industries were conducted. The frequency environment was divided in four conditions (single frequency, multi frequency, random frequency, and intermittent frequency). For single, multi and random frequency conditions, a magneto-mechanical system was applied as the method of harvesting more energy utilizing magnetic forces. For an intermittent condition, system design was conducted as the method to overcome the offresonance region. In single frequency environment, conveyor belts within a smart factory were presented as an experimental environment and the study was conducted to overcome an environment using magnets on the core belt that is much lower than the resonant frequencies of a typical piezoelectric device. In multi frequency environment, water pipes located in plants or buildings were presented as an experimental environment, and to harvest more energy, a hybrid system using piezoelectric energy harvester and electromagnetic energy harvester was studied. In a random frequency environment, the railway was proposed as experimental condition and the magnetic pendulum energy harvester utilizing inertial moments was developed. The energy harvester for the intermittent frequency environment was studied, taking into account the wireless switch that is sometimes pressed by humans as one of the intermittent frequency environments. Third, the research was carried out on the energy harvesting circuit, which is essential for applying the energy harvester to the actual IIoT environment. Preferentially, equivalent circuit modeling of piezoelectricity and impedance matching study was conducted to deliver maximum power. The DC-DC converter study was also conducted to convert high voltage of the piezoelectricity into low voltage so that actual sensor applications can be self-driven by the energy harvester. Additionally, the research was conducted to create the desired output voltage, and finally to establish the wireless communication interface.

VIEW FULL THESIS: https://www.mediafire.com/file/41mjvvokgymxczk/Self-powered+Sensor+Monitoring+System+in+Industrial+Internet+of+Things+using+Off-resonance.pdf/file

Projeto otimizado para minimização de perdas em um conversor bidirecional aplicado a sistemas autônomos de iluminação-Tese de doutorado- Autoria:Duarte, Renan Rodrigo-UNIVERSIDADE FEDERAL DE SANTA MARIA-BRASIL

 

RESUMO 

O presente trabalho apresenta o desenvolvimento de um sistema autônomo de iluminação pública baseado em energia solar fotovolaica e diodos emissores de luz (LEDs). O sistema deve ser capaz de carregar um banco de baterias durante o dia através de um arranjo fotovoltaico e suprir uma carga LED durante a noite. Um conversor bidirecional com transistores de nitreto de gálio (GaN) é utilizado de forma a obter uma estrutura com elevado rendimento e, com isso, otimizar o tamanho do banco de baterias e arranjo fotovoltaico para maximizar a autonomia do sistema ou reduzir os custos de produção, dependendo dos objetivos da aplicação. Foi desenvolvida uma metodologia completa e otimizada para o projeto dos elementos deste sistema autônomo de iluminação. Esta metodologia baseia-se em um algoritmo de busca discreta que avalia um conjunto de componentes disponíveis comercialmente para determinar a melhor combinação de componentes e o melhor ponto de operação do circuito, de modo a minimizar as perdas de energia ao longo do período de operação do sistema. Neste documento é apresentada, inicialmente, uma revisão bibliográfica de aspectos teóricos relacionados aos sistemas autônomos de iluminação, como fonte fotovoltaica, baterias, carga LED, topologias de conversores e soluções comerciais disponíveis. Uma revisão sobre interruptores GaN também é apresentada, abrangendo seu histórico, princípio de funcionamento, características e estado da arte da tecnologia em termos de dispositivos comerciais. Para validar experimentalmente a topologia proposta, um protótipo de 100 W com frequência de comutação arbitrária foi desenvolvido e avaliado. No modo carregador de bateria, o circuito opera em 250 kHz e apresenta eficiências maiores que 92% em toda a faixa de potência com um valor máximo de 97,3%. No modo driver de LED, a frequência de operação escolhida foi de 345 kHz e uma eficiência máxima de 95,8% foi obtida. Para a validação da metodologia de projeto proposta, quatro conversores com potências de 30 W em modo driver e 150 W em modo carregador foram implementados e testados em diferentes pontos de operação. Com isso, comprovou-se que, considerando um conjunto de componentes, a metodologia é capaz de determinar o melhor ponto de operação para maximizar o rendimento, e, considerando diferentes conjuntos de componentes, determinar o melhor em termos de redução da energia perdida, de forma a maximizar a autonomia do sistema.

VER TESE COMPLETA:

 https://repositorio.ufsm.br/bitstream/handle/1/25767/TES_PPGEE_2022_DUARTE_RENAN.pdf?sequence=1&isAllowed=y

Doctoral Dissertation A Three-Phase SCVD Based Boost Inverter with Low Common Mode Voltage for Transformerless Photovoltaic Grid-Connected System Department of Electrical Engineering Graduate School, Chonnam National University BY Tran Tan Tai

(Abstract)

 This study deals with a new type of inverter called a three-phase SCVD based boost inverter. The introduced structure is a combination of an SCVD network and the three-phase bridge to restrict the common-mode voltage. Therefore, the introduced inverter can produce a high output voltage from the low input voltage. The DC-bus voltage of the introduced solution stands at twice of the input voltage. Moreover, the variation in common-mode voltage can o be restricted within one-sixth of DC-bus voltage. Modeling, circuit analysis, operating principles, and a comparison between the introduced SCVD based boost inverter with the other VSIs are performed. To confirm the performance improvements of the introduced SCVD based boost inverter, a preliminary prototype of the introduced SCVD based boost inverter is built in the laboratory and the simulation studies based on PLECS environment and experimental studies are performed. Besides that, a modified SCVD based boost inverter is also introduced to step up the DC-bus voltage to triple of input voltage instead of twice of input voltage like that in the proposed SCVD based boost inverter. Furthermore, a common-mode voltage of the modified SCVD based boost inverter is x canceled through switching the four extra active-switches based on the Boolean logic function. As a result, common-mode voltage is maintained as constant at the value of 0 V during all time. Moreover, the voltage stress across additional semiconductor devices is standing at one-third of DC-bus voltage. The simulation studies based on PLECS environment prove the effectiveness of the modified SCVD based boost inverter. Finally, to validate the performance, operating principle, and feasibility of the modified SCVD based boost inverter, the experimental studies based on the laboratory prototype with a DSP F280049C are carried out. Doctoral Dissertation A Three-Phase SCVD Based Boost Inverter with Low Common Mode Voltage for Transformerless Photovoltaic Grid-Connected System Department of Electrical Engineering Graduate School, Chonnam National University BY Tran Tan Tai (Abstract) This study deals with a new type of inverter called a three-phase SCVD based boost inverter. The introduced structure is a combination of an SCVD network and the three-phase bridge to restrict the common-mode voltage. Therefore, the introduced inverter can produce a high output voltage from the low input voltage. The DC-bus voltage of the introduced solution stands at twice of the input voltage. Moreover, the variation in common-mode voltage can o be restricted within one-sixth of DC-bus voltage. Modeling, circuit analysis, operating principles, and a comparison between the introduced SCVD based boost inverter with the other VSIs are performed. To confirm the performance improvements of the introduced SCVD based boost inverter, a preliminary prototype of the introduced SCVD based boost inverter is built in the laboratory and the simulation studies based on PLECS environment and experimental studies are performed. Besides that, a modified SCVD based boost inverter is also introduced to step up the DC-bus voltage to triple of input voltage instead of twice of input voltage like that in the proposed SCVD based boost inverter. Furthermore, a common-mode voltage of the modified SCVD based boost inverter is canceled through switching the four extra active-switches based on the Boolean logic function. As a result, common-mode voltage is maintained as constant at the value of 0 V during all time. Moreover, the voltage stress across additional semiconductor devices is standing at one-third of DC-bus voltage. The simulation studies based on PLECS environment prove the effectiveness of the modified SCVD based boost inverter. Finally, to validate the performance, operating principle, and feasibility of the modified SCVD based boost inverter, the experimental studies based on the laboratory prototype with a DSP F280049C are carried out.

VIEW FULL DOCTORAL DISSERTATION:

http://www.riss.kr/search/Search.do?colName=all&isDetailSearch=N&searchGubun=true&oldQuery=&sflag=1&fsearchMethod=search&isFDetailSearch=N&searchQuery=A+Three-Phase+SCVD+Based+Boost+Inverter+with+Low+Common+Mode+Voltage+for+Transformerless+Photovoltaic+Grid-Connected+System&kbid=&pageNumber=1&query=A+Three-Phase+SCVD+Based+Boost+Inverter+with+Low+Common+Mode+Voltage+for+Transformerless+Photovoltaic+Grid-Connected+System

LINK ALTERNATIVO DOCTORAL DISSERTATION:

https://www.mediafire.com/file/ciiom9klno2j511/A+Three-Phase+SCVD+Based+Boost+Inverter+with+Low+Common+Mode+Voltage+for+Transformerless+Photovoltaic+Grid-Connected+System.pdf/file

GaN MOSFET를 이용한 유도전동기 구동용 고효율 인버터에 관한 연구 = A Study on the high efficiency inverter for driving an induction motor using GaN MOSFET by Park, Sang-Yong- Dept. of Electronic Engineering The Graduate School Hanyang University

   

A Study on the High Efficiency Inverter for Driving an Induction Motor using GaN MOSFET Park, Sang-yong Dept. of Electronic Engineering The Graduate School Hanyang University

ABSTRACT 

 It was proved in this paper that the efficiency of the inverter using GaN MOSFET ,which is regarded as a next generation power semiconductor, was much improved comparing the efficiency to the counterpart using the conventional Si MOSFET. Comparing the characteristics of GaN MOSFET to those of Si MOSFET, GaN MOSFET shows very low on resistance and very fast switching speed due to the high breakdown voltage and very small parasitic capacitances. Therefore, using GaN MOSFET as switching devices of the inverter, it is expected that the efficiency and characteristics of the inverter can be improved since the switching and conduction losses and switching noise can be reduced. In this paper, to demonstrate the superiority of GaN MOSFET to Si MOSFET, the inverter using GaN MOSFET for driving a 2.2 kW induction motor was fabricated. The design specification of the inverter fabricated is as follows: input voltage is 220 Vac, switching frequency is 20 kHz, and the operating frequency is 0 to 70 Hz. The fabricated inverter was tested and the normal operation of the inverter was confirmed. Finally the efficiency of the inverter was measured and the results of measured efficiency was compared to those of Si MOSFET inverter with the same specification as the GaN MOSFET inverter fabricated. From the comparison results, it is known that the efficiency of the GaN MOSFET inverter is superior to that of Si MOSFET inverter at the full range of load. The maximum efficiency of the GaN MOSFET inverter was measured as 98.41 %.

VIEW FULL TEXT:

http://www.riss.kr/search/detail/DetailView.do?p_mat_type=be54d9b8bc7cdb09&control_no=8f84b308625e5129ffe0bdc3ef48d419&keyword=inverter%20gan

ESTRUCTURAS DE CONVERSIÓN PARA SISTEMAS FOTOVOLTAICOS DE ALTA POTENCIA Memoria que, para optar al grado de Doctor Ingeniero Industrial, por Mikel Borrega Ayala -DEPARTAMENTO DE INGENIERIA ELECTRONICA-UNIVERSIDAD PUBLICA DE NAVARRA

 

1.2 Objetivos de la tesis

. La red eléctrica es de naturaleza alterna, con lo que si se quiere inyectar energía en la red se debe de hacer mediante corriente alterna. Sin embargo, la corriente proporcionada por un generador fotovoltaico es de naturaleza continua. Es por ello que se hace necesaria la utilización de una etapa de conversión electrónica DC/AC, denominada inversor. En las instalaciones fotovoltaicas de conexión a red se utilizan tanto inversores trifásicos, que inyectan la potencia generada a una red trifásica, como inversores monofásicos que la inyectan a una fase. Normalmente, en instalaciones de potencias inferiores a 4.6-6kW4, se utilizan inversores monofásicos. En instalaciones de más potencia, tanto domésticas como grandes plantas, se utilizan inversores trifásicos.

Esta tesis se va a centrar en los inversores fotovoltaicos de conexión a red utilizados en grandes plantas de generación eléctrica. Tal y como se ha apuntado anteriormente, estas instalaciones tienen una potencia de entre 1MW y los 247MW de la instalación más grande del mundo a día de hoy. Se suelen ubicar en lugares con una alta irradiación, aprovechando terrenos de escaso valor urbanístico o para la agricultura. El factor económico es, por lo tanto, el principal parámetros a tener en cuenta en el diseño de este tipo de instalaciones ya que se busca la mayor rentabilidad. Así, los costes de todos los elementos que componen la instalación, incluido el inversor, tienen que ser lo menor posibles. El coste del inversor en relación a la potencia del mismo, ratio €/Vat, suele ser mejor en los inversores de mayor potencia y es por ello que, en este tipo de instalaciones en las que se busca una etapa de conversión lo más económica posible, se utilizan los mayores inversores del mercado con potencias de entre 500kW y 1MW, en lugar de una cantidad mayor de inversores de menor potencia. Es precisamente el diseño de estos inversores de gran potencia el objetivo principal de esta tesis.

Cabe destacar que el hecho de que se busque la instalación más económica posible no siempre va ligado a que el inversor tenga que ser lo más barato posible. Lo importante es conseguir la mayor rentabilidad de la totalidad de la instalación, y eso requiere en ocasiones encarecer ligeramente el inversor si con ello se mejoran ciertas prestaciones del mismo que finalmente desembocan en el abaratamiento de otro elemento de la instalación, o en el aumento de la productividad de la misma.

El factor más importante que hace que las características de un inversor difieran de las de otros, es la arquitectura utilizada en cada uno de ellos. En estos inversores fotovoltaicos de alta potencia existen tres topologías principales. La primera de ellas es el Inversor Centralizado (IC). Se trata de una etapa de conversión única por la cual circula la totalidad de la potencia inyectada a la red. Por un lado entra la potencia proveniente del campo solar, que es de carácter continuo. El inversor convierte la potencia en forma alterna para poder inyectarla a la red eléctrica que es también de carácter alterno. La red eléctrica a la que se conectan este tipo de inversores de gran potencia es de tipo IT, con el neutro aislado de tierra.

VER LA TESIS COMPLETA:  https://academica-e.unavarra.es/xmlui/bitstream/2454/29278/1/04%20Tesis%20doctoral%20Mikel%20Borrega%20Ayala.pdf