Implementación de un Control Digital de Potencia Activa y Reactiva para Inversores. Aplicación a Sistemas Fotovoltaicos Conectados a Red - Linda HASSAINE DEPARTAMENTO DE TECNOLOGÍA ELECTRÓNICA UNIVERSIDAD CARLOS III DE MADRID

TESIS DOCTORAL Implementación de un Control Digital de Potencia Activa y Reactiva para Inversores. Aplicación a Sistemas Fotovoltaicos Conectados a Red 
Autor: Linda HASSAINE DEPARTAMENTO DE TECNOLOGÍA ELECTRÓNICA UNIVERSIDAD CARLOS III DE MADRID

 RESUMEN Esta tesis se centra en los sistemas fotovoltaicos conectados a la red eléctrica. El objetivo principal es controlar la potencia inyectada a la red desde los paneles solares, optimizando el diseño y el control de los inversores cuando se emplean como interfaz entre la red eléctrica y los sistemas fotovoltaicos para entregar energía a la red con la mejor calidad posible y según las exigencias de la red. El control del la potencia inyectada a la red no solamente incluye el control de la potencia activa, sino también la potencia reactiva. En esta tesis, se propone un algoritmo sencillo y robusto para el diseño del control del inversor conectado a la red, basado en la utilización del control digital DSPWM “Digital Sinusoidal Pulse Width Modulation”, asociado al control del desfase entre la tensión de salida del inversor y la tensión de la red. A nivel de diseño, en esta tesis se desarrollan y se analizan las limitaciones de los convertidores VSCs “Voltage Source Converters” como inversores para entregar potencia activa y reactiva a la red asegurando una óptima conexión desde los paneles solares, cuidando el funcionamiento del inversor y mejorando el factor de potencia y el contenido armónico de la corriente inyectada a la red. Desde el punto de vista del control, se ha desarrollado una nueva estrategia de control. Se propone un método de control del inversor que permite controlar no solo la corriente inyectada a la red y el factor de potencia sino que, de forma dinámica, puede reconfigurarse para cambiar el tipo de factor de potencia que se desea entregar a la red dependiendo de las necesidades de la red eléctrica. El control se basa en la utilización de un número mínimo de patrones de disparo previamente calculado y tabulado aplicado a una tensión del bus de continua constante. Actuando sobre el desfase de la tensión de salida del inversor como parámetro de control, se puede controlar la amplitud de la corriente de salida, el factor de potencia y, por lo tanto, la magnitud de la potencia entregada a la red, tanto activa como reactiva. Una de las ventajas que nos proporciona este método de control es su simplicidad en cuanto a los requerimientos de capacidad de cómputo del circuito de control y por otra Resumen X parte nos permite reconfigurar el control de manera rápida y sencilla en caso de que se requiera inyectar no solo potencia activa, sino también potencia reactiva. Se analiza el comportamiento de éste método para diferentes configuraciones dentro del sistema de control global, utilizando a la salida del inversor un filtro L y un filtro LCL calculando la distorsión armónica total de la corriente para cada configuración. Se presenta el método para el seguimiento del punto de máxima potencia y la estructura de los lazos de control, así como el método seguido para calcular los reguladores y la implementación digital del control. Se presentan el controlador de corriente y el controlador de tensión del DC-bus, el modulador de fase, desarrollando un modelo de ecuaciones lineales para el diseño del controlador y se analiza la estabilidad del inversor conectado a la red eléctrica. Dentro de esta línea de investigación y para llevar a cabo el control digital del inversor, se ha realizado, en primer lugar, la implementación de las técnicas de modulación sinusoidal del ancho del pulso SPWM “Sinusoidal Pulse Width Modulation”, bipolar y unipolar, de forma digital. La implementación del modulo SPWM digital que forma parte del control del inversor se ha realizado en una FPGA “Field Programmable Gate Array” validando los resultados de simulación y experimentales. El funcionamiento del control propuesto se ha validado mediante simulaciones de los modelos promediado y conmutado del inversor con control de fase. Por último este control ha sido implementado en una FPGA y validado con los resultados de simulaciones y experimentales.

LINK
https://e-archivo.uc3m.es/bitstream/handle/10016/10230/Tesis_Linda_Hassaine.pdf?sequence=1&isAllowed=y

A Study on the Algorithm for Single Phase Control of IGBT PWM Rectifier Seung-Ho Kim, Jae-Beom Park, Dong-Hyun Tae, Seung-Jong Kim, Joong-Ho Song, Dae-Seok Rho Korea University of Technology & Education, Global Electricity Co., Ltd, Seoul National University of Science and Technology

A Study on the Algorithm for Single Phase Control of IGBT PWM Rectifier Seung-Ho Kim, Jae-Beom Park, Dong-Hyun Tae, Seung-Jong Kim, Joong-Ho Song, Dae-Seok Rho 
 Korea University of Technology & Education, Global Electricity Co., Ltd, Seoul National University of Science and Technology

 Abstract
 Recently, the use of transformer-less UPS has increased to improve the efficiency of UPS. However, transformer-less UPS is required in three-phase four-wire input IGBT PWM rectifier and the existing three-phase three-wire PFC algorithm cannot be applied in the three-phase four-wire system due to the neutral current problem of UPS input. To control the three-phase four-wire input IGBT PWM rectifier, there are two existing algorithms: 3D SVM and single phase control method. These two algorithms have advantages/disadvantages in controlling the rectifier. The single phase control method is unstable for controlling the rectifier and the 3D SVM method has a problem that must increase the L value of the input-side inductor considerably. Therefore, this paper proposes digital single phase control technology and another new algorithm considering the d-q control, to improve the characteristics of the existing control algorithm. In addition, this paper performed a simulation and experiment based on the proposed control algorithm. The simulation results showed that the proposed technology can control three-phase four-wire IGBT PWM rectifier in a stable manner and can also reduce the neutral current. The proposed algorithm is a useful tool for controlling the three-phase four-wire IGBT PWM rectifier.

 Keywords : UPS, IGBT PWM Rectifier, Single Phase Control, d-q Control. UPS;IGBT PWM Rectifier;Single Phase Control;d-q Control;
LINK FULL PAPER:
http://www.koreascience.or.kr/article/ArticleFullRecord.jsp?cn=SHGSCZ_2016_v17n4_26

An Electrical Power System for CubeSats Presented by: Benjamin C. de V. Sheard Dept. of Electrical and Electronics Engineering University of Cape Town

An Electrical Power System for CubeSats
Presented by:
Benjamin C. de V. Sheard
Supervisor:
Mr. Samuel I. Ginsberg
Dept. of Electrical and Electronics Engineering
University of Cape Town
Submitted to the Department of Electrical Engineering at the University of Cape
Town in partial fulfilment of the academic requirements for a Master of Science
degree in Electrical Engineering.
ABSTRACT
The advent of CubeSats has provided a platform for relatively low-budget programmes to realise space missions. In South Africa, Stellenbosch University and the Cape Peninsula University of Technology have impressive space programmes and have been involved in numerous successful satellite launches. A number of CubeSat projects are currently in progress and commercial-grade Attitude Determination and Control Systems (ADCS), and communications modules, are being developed by the respective universities. The development of a CubeSat-compatible Electrical Power System remains absent, and would be beneficial to future satellite activity here in South Africa. In this thesis, some fundamental aspects of electronic design for space applications is looked at, including but not limited to radiation effects on MOSFET devices; this poses one of the greatest challenges to space-based power systems. To this extent, the different radiation-induced effects and their implications are looked at, and mitigation strategies are discussed. A review of current commercial modules is performed and their design and performance evaluated. A few shortcomings of current systems are noted and corresponding design changes are suggested; in some instances these changes add complexity, but they are shown to introduce appreciable system reliability. A single Li-Ion cell configuration is proposed that uses a 3.7 V nominal bus voltage. Individual battery charge regulation introduces minor inefficiencies, but allows isolation of cells from the pack in the case of cell failure or degradation. A further advantage is the possibility for multiple energy storage media on the same power bus, allowing for EPS-related technology demonstrations, with an assurance of minimum system capabilities. The design of each subsystem is discussed and its respective failure modes identified. A limited number of single points of failure are noted and the mitigation strategies taken are discussed. An initial hardware prototype is developed that is used to test and characterise system performance. Although a few minor modifications are needed, the overall system is shown to function as designed and the concepts used are proven.
LINK
https://open.uct.ac.za/bitstream/handle/11427/20101/thesis_ebe_2015_sheard_benjamin_charles_de_villiers.pdf?sequence=1

ENIE 2018 – FEIRA E CONGRESSO-XVII ENCONTRO DE INSTALAÇÕES ELÉTRICAS 28/08/2018 a 30/08/2018-SÃO PAULO BRASIL

DATA 28/08/2018 a 30/08/2018 LOCAL Expo Center Norte – Pavilhões Verde e Branco- Rua José Bernardo Pinto, 333 – Vila Guilherme - São Paulo - SP

LINK

http://www.arandaeventos.com.br/eventos2018/enie/html/index.html

Research on a GaN HEMT On-Board Charger for Electric Vehicles Thesis for the degree of Doctor of Philosophy Guoen Cao-Dept. of Electronic Systems Engineering Hanyang University

Research on a GaN HEMT On-Board Charger for Electric Vehicles 
 Thesis for the degree of [Doctor of Philosophy Guoen Cao Hanyang University Graduate School

 ABSTRACT
Research on a GaN HEMT On-Board Charger for Electric Vehicles Guoen Cao Dept. of Electronic Systems Engineering The Graduate School Hanyang University With an accelerating global energy crisis and deteriorating environmental problems, electric vehicle (EV) technologies have attracted growing interest due to their reduced fuel usage and greenhouse emissions. The battery charger plays a critical role for the acceptance and development of EVs. Because a battery is generally used as the main power source, a high conversion efficiency, high power density, and lightweight on-board-charger (OBC) is needed in order to maximize the energy utilization. Gallium nitride based high electron-mobility transistors (GaN HEMTs) are potential candidates as next-generation power switching devices due to the enormous potential use in the applications of high frequency, high temperature, and high output power, in particular of battery charger applications. Although much progress has been achieved in the development of GaN HEMTs, a few important issues such as current collapse effects should be evaluated before wide deployment is possible. Since evaluating performance in power semiconductors and selecting the optimal topologies are important steps in the design and development of power electronics circuits, this thesis is concerned with the performance evaluation of the new GaN HEMTs and the design of an isolated OBC that uses GaN HEMTs to achieve high efficiency for future applications in EVs. GaN HEMTs suffer from current collapse effect in operation regions, which leads the dynamic on-resistance to increase when a high voltage is applied to the transistor. In order to measure the dynamic on-resistance and evaluate the current collapse effect of newdesigned GaN HEMTs, a novel soft-switching measurement circuit based on synchronous buck topology is introduced. To apply high-voltage and high-current stresses to the device without additional spikes and oscillation, the resonance technique has been employed. As a result, the proposed circuit can produce sufficient high frequency switching voltage and current stresses equal to or greater than that would be found in real power applications to the devices with general equipment. In order to achieve accurate measurement of onresistance under high frequency switching operations and eliminate the saturation of conventional methods, an active voltage clamp circuit is developed. A prototype circuit has been built. Experiments conducted under extreme conditions have been carried out. The simulation and experimental results confirm the validity of the proposed circuit. After evaluating characteristics of the new-designed GaN HEMTs, an isolated high efficiency on-board battery charger using these new power devices is presented. The OBC has a two-stage structure, where the first stage is an interleaved boost AC-DC power factor correction (PFC) converter and the second stage is a full-bridge LLC resonant converter. As the GaN HEMT has very low gate threshold voltage, a high-speed isolated gate driver circuit with negative voltage has been developed for the efficient operation of the two stages For the GaN-based PFC converter, circuit modeling and the power stage design method are discussed in detail. To keep high power factors and high dynamic performance under a wide input and output range, a fuzzy logic PI current controller and a non-linear voltage controller based on the circuit model are proposed. A 1.5 kW hardware prototype is developed and a maximum system efficiency of 97.5% is measured while operating with the switching frequency of 200 kHz. The results also show a considerable increase in system efficiency and superior performance of the proposed converter compared to the conventional control methods.
For the full-bridge LLC resonant converter, a novel design method for lithium battery charger applications is proposed. According to the charging characteristics, three operating points are selected for the optimum design. A thorough analysis of design procedure is performed, considering the performance evaluation of GaN HEMTs. A 1.5 kW prototype circuit was built, with an output voltage range of 250 V to 420 V. Experimental results show that high efficiency of 95.9% is achieved by using GaN HEMTs and it has resulted in 0.9% improvement compared to the conventional silicon-based converter. In order to implement digital control and control the two-stage in an effective way, a two-core floatingpoint DSP is employed for the OBC. Keywords Electric vehicles, battery charger, GaN HEMT, evaluation circuit, interleaved PFC, fuzzy logic control, soft-switching, LLC resonant converter