Novel Hybrid Unidirectional Three-Phase AC-DC Converter Systems by KAZUAKI MINO-Swiss Federal Institute of Technology (ETH) Zurich

Novel Hybrid Unidirectional Three-Phase AC-DC Converter Systems by KAZUAKI MINO A dissertation submitted to Swiss Federal Institute of Technology (ETH) Zurich EIDGENÖSSISCHE TECHNISCHE HOCHSCHULE ZÜRICH for the degree of Doctor of Sciences Presented by Kazuaki Mino E.E., M.Sc., Tokyo Denki University born December 23, 1968 citizen of Japan Accepted Accepted on the recommendation of Prof. Dr. J. W. Kolar, Examiner Prof. H. Akagi, Co-Examiner

Abstract

In order to reduce harmonics, many rectifier topologies have been developing. Passive rectifiers, which employ only passive components, e.g. phase shifting transformers, diode bridges, and inductors etc., show some advantages concerning high efficiency, low EMC, low complexity, and high reliability. The passive components could be compact if mains frequency is high as in aircraft and micro gas turbine applications. However, the output voltage is unregulated. Furthermore, the input current of the passive rectifiers results in a staircase waveform which is not high quality if compared to active rectifiers. In this thesis, the drawbacks of the passive rectifiers are reduced. A diode bridge rectifier whose harmonics are reduced by adding an inductor to a diode bridge is widely used in motor drive applications. Mains current quality of the diode bridge rectifier is improved if a large inductance of the passive inductor is employed. However, the inductor is bulky, heavy and occupies a large space. In this thesis, the power density of the diode bridge rectifier is improved. The Electronic Smoothing Inductor, which is able to control a current to a constant value, is applied to the diode bridge output to act as a passive inductor. A control scheme for the DC-link voltage and active damping control for filter resonances are proposed. Moreover, the filtering concept is established to effectively attenuate EMI emission. The system dimensioning of the rectifier system is also introduced. A 5kW prototype shows a significant improvement in power density. The behaviours of the proposed rectifier system are tested by assuming practical conditions, e.g. not only ideal but also unbalanced and distorted input conditions. The dynamic behaviours are also evaluated. From the results, it is verified that the Electronic Smoothing Inductor has a similar characteristic to a passive inductor having a large inductance. Therefore, the proposed rectifier system brings a significant improvement in power density without impairing any features of a diode bridge rectifier. On the other hand, the passive 12-pulse rectifier can be extended to a hybrid rectifier having two active switches operated in an interleaved manner. The proposed topology ensures a controlled output voltage. Furthermore, modulation schemes to realize a purely sinusoidal input current are proposed. A 10kW prototype has been build with respect to future more-electric aircraft applications. The design procedure including the magnetic components and the active parts is introduced in this thesis. The proposed hybrid rectifier and the control schemes are verified by numerical simulations and experimental results. The output voltage is regulated. Furthermore, the input current is improved from a 12-pulse staircase shape to sinusoidal by the proposed triangular modulation. Moreover, the proposed closed loop control of input currents is performed to track a reference independently of mains voltages e.g. unbalanced and distorted input voltages. Therefore, both output voltage regulation and improvement of input current quality for the 12-pulse rectifier have been achieved by the proposed schemes. This thesis presents two rectifier systems which perform successfully. Both systems are hybrid and allow output power to flow without switching behaviours. Therefore, the proposed rectifier systems have not only high quality characteristics but also a high reliability. The system configurations, control schemes and their features are introduced. 

LINK http://www.mediafire.com/file/0tokqbgz47ukn4e/eth-144-02.pdf/file

Hybrid DC/DC Converter for Electric Vehicle (EV) On-Board Charger (OBC) Using Full-Bridge (FB) and Resonant Converter with Single Transformer Najam ul hassan Department of Electrical Engineering Graduate School, Myongji University

Hybrid DC/DC Converter for Electric Vehicle (EV) On-Board Charger (OBC) Using Full-Bridge (FB) and Resonant Converter with Single Transformer Najam ul hassan Department of Electrical Engineering Graduate School, Myongji University Advisor Professor Lee Jun-young

ABSTRACT

In this document a highly efficient hybrid DC/DC converter is proposed. Its design procedure, analysis and experimental results are presented by testing of the implemented prototype and. whole document is arranged into six chapters. Electrical vehicle battery chargers background, power level, different charging methods and purpose of the document is presented in chapter 1. High power DC/DC converter topologies suggested recently, and its benefits and drawbacks are briefly discussed in chapter 2. Proposed converter diagram, operational analysis and comparison of proposed converter with other DC/DC converter topologies are presented in chapter 3. Chapter 4 is about design procedure. Based on the design procedure suggested in chapter 4, prototype design and simulation results are given in chapter 5 and experimental results are given in chapter 6. Most of the previously proposed hybrid converters have used two transformers for each converter in hybrid structure that makes the size of the converter bulky and there was also low utilization and the power distribution problem between two transformers of the hybrid converters. To solve this problem, a new high efficient hybrid DC/DC converters using single transformer, which has characteristics of Full-bridge and resonant convertor for EV OBC, is proposed in this vii thesis. By using single transformer the power distribution problem has been solved and transformer utilization has become high. In the proposed converter, magnetizing inductance has been used at the primary side of the transformer to obtain the soft switching such as zero voltage switching (ZVS). Leakage inductance of the transformer has been used as resonant inductor on the secondary side to avoid the use of separate inductor as resonant. The prototype of 6.6KW has been implemented to verify the feasibility of the proposed converter and maximum efficiency of 97.4 is achieved at 413 V.

LINK http://www.mediafire.com/file/fd3hegpispv96nv/Hybrid_DCDC_CONVERTER_EV_CHARGER.pdf/file

UPS Topologies for the Elimination of Inrush Current Phenomenon Associated with Transformer-Coupled Loads-Syed Sabir Hussain Bukhari Graduate School of Hanyang University

UPS Topologies for the Elimination of Inrush Current Phenomenon Associated with Transformer-Coupled Loads Syed Sabir Hussain Bukhari Department of Electronic System Engineering The Graduate School Hanyang University 

ABSTRACT
 Many critical load applications depend upon UPS system to uphold power in the course of outages as well as during under- and over-voltage grid conditions. Once any disruption occurs at the grid, a UPS system either takes over the load completely or injects the compensation voltage to the load to avoid interruption. For an off-line and line-interactive UPS systems, this transfer of load takes a minimum of 1–5 msec and can be as much as 20 msec, mainly depending upon the time required for the fault detection and the operating mechanisms of the transfer switches. Throughout this time duration, the load transformer, accompanied by the sensitive load is probable to be exposed to the distorted grid voltage. As a result, a flux-offset of the load transformer is established. Thus, as soon as the UPS system takes over the load and reinstates its voltage, the transformer flux might increase above its saturation level and generates substantial inrush current. In the case of an on-line UPS topology, the load transfer time period is zero. The phenomenon of inrush current for an on-line UPS system is observed when it powers multiple transformer-coupled loads. Under such a condition, the switching-in of a load when other loads are already on-line can cause a large magnitude of inrush current because of the energizing of the load transformer. This inrush current can take several cycles, which reduces the line voltages and triggers over-current protecting devices of the UPS systems. In this research, an off-line UPS system based on current regulated voltage source inverter (CRVSI) instead of conventional voltage source inverter is proposed. The inverter of the UPS system utilizes a current control algorithm implemented in the stationary frame. This enables an off-line UPS system to eliminate the inrush current during the transition while powering a transformer-coupled load. To eliminate the inrush current phenomenon related with a line-interactive UPS system and to achieve fast current injection by the inverter during any abnormal grid power condition, a new line-interactive UPS system is proposed in this research that uses a standard current regulated inverter coupled with the secondary of the load transformer. The possibility of inrush current is eliminated with an instantaneous compensation of load current and a seamless transition of a load. This research also proposes an on-line UPS topology with eliminated inrush current while operating with multiple transformer-coupled loads, achieved through a swift performing current regulated inverter operating with a control scheme consists of two control loops to supply the additional current caused by the switching-in of the loads. The outer voltage control loop controls the load voltage. However, the inner current loop controls the load current to vary it sinusoidally as per the supplementary load demand during the engagement of other load transformers, leaving behind any possibility of inrush current generation. All of the above mentioned UPS topologies are well-analyzed and implemented through simulation and experimental results. A comparison between the conventional static UPS topologies and the proposed UPS topologies is also provided in this research.

ORIGINAL LINK:http://www.riss.kr/search/detail/DetailView.do?p_mat_type=be54d9b8bc7cdb09&control_no=e0fe01fc0fc571f5ffe0bdc3ef48d419

LINK http://www.mediafire.com/file/yute4gnsxo2es6n/UPS_Topologies_for_the_Elimination_of_Inrush_Current.pdf/file

A Study on The Control Technique for Modular Three-Phase Uninterruptible Power Supply(UPS) With Boost Converter Jin, Seongmin Dept. of Electrical Engineering Incheon National University-SOUTH KOREA

A Study on The Control Technique for Modular Three-Phase Uninterruptible Power Supply(UPS) With Boost Converter Jin, Seongmin Dept. of Electrical Engineering Incheon National University

ABSTRACT
 This study proposes a control algorithm design and implementation method for the control method of the modular three phase uninterruptible power supply (UPS) with boost function. With the development of the industrial age, there has been an increase in the load required to maintain the constant power source, which has increased the demand for the uninterruptible power supply. In addition, a parallel type uninterruptible power supply unit of a modular type is widely used to satisfy a load of a high capacity It is difficult to apply a desired output voltage to a load by using a 250V DC voltage as the input power source of a UPS used in a power plant system. Therefore, it is necessary to design a module suitable for UPS system for power plant. A UPS for applying 3-phase AC voltage to a load is generally composed of a 3-phase inverter and an output L-C filter. In order to apply this to the power plant system, it is necessary to construct and control a power converter for a single module that boosts the input voltage by applying a boost converter to the input of the inverter to supply the constant voltage to the inverter. In addition, a parallel operation control technique is necessary to solve the problem of connecting such a single module in parallel. Therefore, in this study, the study on the configuration, design and parallel operation control technique for single module UPS for power plant was conducted. The proposed algorithm proved its superior performance and feasibility through simulation and experimental results Key words: Uninterruptible power supply, single module power converter for plant, parallel operation control

LINK A:http://www.riss.kr/search/detail/DetailView.do?p_mat_type=be54d9b8bc7cdb09&control_no=720abcc1b0b8a4c6ffe0bdc3ef48d419

LINK B :http://www.mediafire.com/file/zgqcnslz3p72edt/A_Study_on_The_Control_Technique_for_Modular_UPS.pdf/file

RESOLVIENDO EJERCICIOS DE CIRCUITOS ELÉCTRICOS 1-PROF.DR. ENG. FERNANDO LOPEZ ARAMBURU-LIMA-PERU

ES PARA MI UNA GRANDE SATISFACCION DIFUNDIR EN MI BLOG LOS VIDEOS DE MI ESTIMADO COLEGA DR. ING. FERNANDO LOPEZ ARAMBURU QUE EN MEDIO A LA PANDEMIA DEL CORONA VIRUS SE HA REINVENTADO DICTANDO SUS CLASES DE MANERA VIRTUAL PARA LA UNIVERSIDAD NACIONAL DE INGENIERIA FACULTAD DE ING. ELECTRICA Y ELECTRONICA,EL ES UN DOCENTE CON MAS 30 AÑOS DE EXPERIENCIA HA TRABAJADO EN LA EMPRESA PRIVADA Y HA SIDO PROFESOR DE CIRCUITOS ELECTRICOS EN MUCHAS UNIVERSIDADES ESTATALES Y PRIVADAS DEL PERU,ES CONOCIDO EN LA COMUNIDAD ACADEMICO COMO 'CHAMPION" INGENIERO,DOTADO DE UN CARISMA UNICO DICTA SUS CLASES CON MUCHA DIDACTICA Y ANALISIS CRITICO,LE ENVIO UN CORDIAL SALUDO.