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Fecha Publicación: 2022-04-04T11:35:00.005-07:00

 Ph.D. Dissertation A Study on Modulated Carrier Control Method for Power Factor Correction Boost Converter BY Jintae Kim 
Interdisciplinary Program in Photovoltaic System Engineering
The Graduate School Sungkyunkwan University

A Study on Modulated Carrier Control Method For Power Factor Correction Boost Converter As demand of electrical devices steeply increases, harmonic pollution on the power grid has attracted concern. This circumstance leads standards such as IEC61000-3-2 and 80-Plus regulating harmonic currents or PF (Power Factor) to have been more stringent. Thus, a PFC (Power Factor Correction) circuit able to improve power quality while reducing current harmonics has been indispensible at the electrical devices. For the reason, the PFC has been constantly researched so that various topologies and control types have been proposed and realized as silicon. So far, many of proposed PFC converters have each optimal operation mode offering good PFC performance such as CCM (Continuous Conduction Mode), DCM (Discontinuous Conduction Mode) or BCM (Boundary Conduction Mode). The same is true of conventional MCC (Modulated Carrier Control) PFC converters. The conventional MCC PFC method does not require sensing the line input voltage and offers very fast dynamic current control by directly comparing an inductor current. These are advantages of the conventional ones. However, these conventional MCC converters enter into DCM by load reduction, the line input current is distorted and harmonic current is increased. In this dissertation, a research on new MCC method is revealed from a study and analysis on the conventional MCC PFC converter. Two types of MCC method are proposed to overcome the problem of the conventional MCC aforementioned. The proposed MCC methods newly employ a circuit to detect DCM region and generate DCM compensation signal in common. Using the compensation, the MCC methods can control the line input current as a desirable sinusoidal waveform, which results in better PFC performance regardless of a line input voltage range or load variation unlike the conventional MCC method. With all them, the proposed method can maintain the advantages of the conventional MCC method and even it can be easily implemented with analog or digital circuits. This dissertation describes the proposed MCC methods and the operating principle. In addition, to verify the proposed methods, they are implemented in 400 W PFC boost converter.

Fecha Publicación: 2022-04-02T13:25:00.011-07:00


Fecha Publicación: 2022-03-26T06:58:00.008-07:00


 PFC (Power Factor Correction) is an effective method to reduce harmonic currents in power grids The control circuit and parameters design of the PFC circuit .
As shown in Fig.2, in Boost PFC circuit, the control core is internal multiplier of UC3854DW, through sampling input voltage Vin, input current Iin and output voltage Vo1, the PWM signal is generated to force the input average current to be in phase with the input voltage, so the power factor is close to 1

                 Figure 2. Boost PFC circuit controlled by UC3854

Fecha Publicación: 2022-03-12T16:54:00.006-08:00

 Study on Large Air-Gap Bi-directional Wireless Battery Charger for Electric Vehicles 
 by Yoo, Kwang Min
 Department of Electrical Engineering Graduate School, Myongji University Directed by professor Lee Jun Young 

 In this paper, we provide battery charging/discharging for electric vehicles, including hybrid car using a wireless power transmission technology. Because the power sources of EV and PHEV are fully or partially supplied from batteries charged from public line, on-board chargers should be mounted. Conventional on-board battery chargers for PHEV or EV have two-stage structure of input current shaper for harmonic reduction followed by DC/DC converter for output control and electrical isolation. And On-board battery charger is installed in the vehicle at all times. So It will account for constant volume of the car. It will contribute a constant fuel consumption of the vehicle by increasing the weight of the electric vehicle. Currently, the most conventional method is plug-in charging, where a copper connected cable forms the power link. There are several disadvantages to this method, which have led to the investigation of inductive charging technology. On-board chargers are burdened by the need for a cable and plug charger, galvanic isolation of the on-board electronics, the size and weight of the charger, and safety and issues with operating in rain and snow. Wireless power transfer (WPT) is an approach that provides a means to address these problems and offers the consumers a seamless and convenient alternative to charging conductively. In addition, it provides an inherent electrical isolation and reduces on-board charging cost, weight and volume. Depletion of fossil fuel reserves and current practice in generation, transmission, distribution, and utilization of energy are major worldwide concerns, for which distributed generation (DG) and harnessing of renewable energy are considered to be partial and acceptable solutions. However, the quality of power delivered by DG systems, particularly those based on wind energy and solar energy, is largely affected by the stochastic nature of their energy production. Consequently, in order to improve the power quality while meeting the demand in the most economical and efficient way, energy suppliers relied on energy storage systems, particularly for DG systems of medium power levels. Among various storage solutions such as flywheels, batteries, super-capacitors, etc., the vehicle-to-grid (V2G) concept, which uses hybrid vehicles or pure electric vehicles (EVs) to store and supply energy back to the grid, is gaining more and more popularity as hybrid.

Fecha Publicación: 2022-03-12T05:42:00.003-08:00


Presented to the Faculty of The University of Texas at Dallas in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE IN ELECTRICAL ENGINEERING 

 The ever growing consumption of data and its handling has resulted in huge server stations which cover prime land space and consumes huge amounts of power at low voltages causing high inefficiency. This work attempts to evaluate the design of a GaN based high efficiency and high power density server PSU. A two-stage topology is considered where an active front end rectifier converts 208VAC 3-phase supply to 380VDC. An isolated DC-DC LLC converter employing a planar integrated matrix transformer steps down the 380VDC to 48VDC for further distribution in the server rack. The rectifier switches and the primary switches in the LLC are GaN MOSFETs. The analytical loss and volume model of the converter are derived and a multi-objective design optimization for reduction in loss and volume is performed. Hence, a suitable converter design parameter is selected and a prototype design is considered.

Fecha Publicación: 2022-03-10T06:03:00.001-08:00


Fabrication and Characterization of Perovskite–Organic Additive Composites for Micro Light-Emitting Diodes
 Dissertation Submitted to the Department of Materials Science and Engineering and the Graduate School of Yonsei University in partial fulfillment of the requirements for the degree of Doctor of Philosophy 
By Do Hoon Kim --February 2022


 Development of micro light-emitting diode (LED) pixel array for ultra-high definition (UHD) displays is underway based on LED semiconductor chips, organic LEDs (OLEDs), and quantum dot LEDs (QLEDs). However, these devices have the drawbacks of high cost and complex processes as well as technical problems. Such as an increase in the cost due to the additional transfer process of semiconductor chips and an inaccuracy of mechanical positioning during repeated transfer process. Moreover, OLEDs have the advantage of being applicable to flexible and stretchable substrates, but require expensive organic materials and large-scale equipment. In case of QLEDs, these are not able to be used as a light source because of unstable electroluminescence (EL) property, thus they are used as color filters with a backplane. So, introduction of candidate of new luminescent materials is urgently needed. The perovskite has an adjustable optical band gap, which can be tuned by changing halide anions in the entire visible region. In particular, a primary advantage of the perovskite is that it can be fabricated by simple solution process at low temperatures and this enables the perovskite to be useful for low-cost and large-area micro LED applications. Furthermore, the perovskite LEDs (PeLEDs) are expected to be suitable for nextgeneration displays because they have exhibited unprecedented improvements of luminescence efficiency in a short time compared to conventional LEDs. However, despite these advantages of perovskites, in the case of CsPbI3 crystals for realizing red emission, a high-temperature post-annealing process is essential for suppressing the formation of δ- phase (tilted octahedral) crystals and promoting the formation of a stable α-phase (cubic). In general, a high-temperature process results in better crystallinity with rapid crystal growth. However, perovskite crystals become large and exhibit many surface defects resulting in a rough surface, long diffusion length of excitons, and dissociation of excitons; these factors lead to non-radiative recombination and a high leakage current. Therefore, several strategies, such as the addition of hydrophilic polymer and ligands to the perovskite precursor, have been studied to prevent the surface defects in PeLEDs. In this dissertation, it was demonstrated that functional groups of poly(2-ethyl-2- oxazoline) (PEOXA) lead to coordination bonds with the metal cations of perovskite. PEOXA can decrease formation temperature of the perovskite nanocrystals and improve phase stability as well. PEOXA added to a CsPbBr0.6I2.4 precursor solution successfully suppressed the formation of δ-phase (tilted octahedral) crystals and promoted the formation of stable α-phase (cubic) CsPbBr0.6I2.4 nanocrystals.

Fecha Publicación: 2022-02-19T16:44:00.005-08:00
                                                                  SCHEMATIC PSPICE




                                       PROBE TRIGGER S1 ,S2 ,S3 , S4

Fecha Publicación: 2022-02-11T17:49:00.004-08:00


Ph.D. Dissertation Fast Transient and High Efficiency Voltage-Regulated PWM Buck Converters 

Jung-Duk Suh
 Department of Electrical and Computer Engineering 
The Graduate School Sungkyunkwan University 

 Abstract Fast Transient and High Efficiency Voltage-Regulated PWM Buck Converters This dissertation proposes three pulse-width modulation (PWM) buck converter architectures; two for fast load transient and one for high efficiency. A fast load transient response for small overshoot or undershoot is very important to designing switching regulator because dynamic voltage scaling is regarded as an effective power management solution. The transient response in the conventional voltage mode converter is limited since a type-3 compensator with large capacitors is used. So, it is important to improve slow transient response problems. Also, improving the efficiency under the light load condition of switching regulators is a very important design because of many portable devices stay in standby mode. In common PWM buck converters, the switching loss is dominant in the light load. So, to improve the performance of PWM buck converters in terms of the light-load efficiency, the switching power consumption should be minimized. In this dissertation, to overcome the speed limitation of the PWM control and the light load efficiency, PWM buck converters that can improve both the load transient response and the light load efficiency are proposed. First, a DC-DC converter with active ramp tracking control (ARTC) is presented. When the difference between the output voltage and reference voltage is increased to the threshold voltage in the load transient situation, the ramp bias voltages change and generate a full duty signal to the power switches. This helps restore the output voltage to the reference voltage, improving the load transient response speed and decreasing the overshoot/undershoot at the output voltage. The proposed converter with ARTC improves the load transient response speed and decreases the overshoot/undershoot at the output voltage. This proposed buck converter with ARTC can reduce the overshoot/undershoot at the output by up to 61.1% and the recovery time up to 60.0 % for a 450-mA load current step. Second, a DC-DC converter with inductor current slope control (ICSC) is presented. In load transient period, the slope of the inductor current is increased two times by connecting the parallel inductor of same size as main inductor. It can recover the output voltage quickly and have a consistent fast response time regardless of the load current step size and output voltage. This proposed buck converter with ICSC simulated in a 65-nm CMOS technology reduces the overshoot/undershoot at the output by up to 54.4% and the recovery time up to 82.6% for a 450-mA load current step. Third, a DC-DC converter with chargerecycling gate-voltage swing control is presented. This proposed converter with charge-recycling gate-voltage swing control can improve the power efficiency by reducing the gate-driving loss at the light load. This proposed converter controls the gate-voltage swing with charge-recycling structure according to the load current and has the gate-driving loss reduced by up to 87.7% and 47.2% compared to the conventional full-swing and low-swing designs, respectively. The maximum power conversion efficiency was 90.3% when the input and output voltages are 3.3 V and 1.8 V, respectively.


Fecha Publicación: 2022-02-06T10:02:00.003-08:00

 Active gate switching control of IGBT to improve efficiency in high power density converters 

 Thesis submitted in partial fulfilment of the requirement for the PhD degree issued by the Universitat Politècnica de Catalunya, in its Electronic Engineering Program 
BY Hamidreza Ghorbani 
Director: Dr. Prof. Jose Luis Romeral Martinez Co-Director: Dr. Eng. Vicent Sala -May 2019 

 Insulated gate bipolar transistor (IGBT) power semiconductors are widely employed in industrial applications. This power switch capability in high voltage blocking and high current-carrying has expanded its use in power electronics. However, efficiency improvement and reducing the size of products is one of main tasks of engineers in recent years. In order to achieve high-density power converters, attentions are focused on the use of fast IGBTs. Therefore, for achieving this desire the trend is designing more effective IGBT gate drivers. In gate drive (GD) controlling, the main issue is maintaining transient behavior of the MOS-channel switch in well condition; when it switches fast to reduce losses. It is well known that fast switching has a direct effect on the efficiency improvement; meanwhile, it is the major reason of appearing electromagnetic interference (EMI) problems in switched-mode power converters. Nowadays the most expectant of an active gate driver (AGD) is actively adjusting the switching transient through simple circuit implementation. Usually its performance is compared with the conventional gate driver (CGD) with fixed driving profile. As a result a proposed AGD has the capability of increasing the switching speed while minimizing the switching stress. Different novel active gate drivers (as feed-forward and closed-loop topologies) have been designed and analysed in this study. To improve the exist trade-off between switching losses and EMI problem, all effective factors on this trade-off are evaluated and considered in proposed solutions. Theoretical developments include proposed controlling methods and simulated efficiency of IGBTs switching control. The efficiency improvement has been pursued with considering EMI study in the proposed active gate controller. Experimental tests have been conducted to verify the design and validate the results. Beside technical aspects, cost study has also considered in the closed-loop GD. The proposed gate drivers are simple enough to allow its use in real industrial applications. 

 Los semiconductores de potencia (IGBT) se emplean ampliamente en aplicaciones industriales. La capacidad de este interruptor de bloqueo en alta tensión y conducción de alta corriente ha ampliado su uso en la electrónica de potencia. Sin embargo, la mejora de la eficiencia y la reducción del tamaño de los convertidores de potencia es una de las tareas principales de los ingenieros de diseño. Para lograr convertidores de potencia de alta densidad y eficiencia, se requiere el uso de IGBT rápidos. Por lo tanto, la tendencia es diseñar controladores de puerta para IGBT más efectivos. En el control de la unidad de puerta (GD), el problema principal es mantener el comportamiento transitorio del conmutador del canal MOS bajo control, cuando conmuta a lata frecuencia para reducir las pérdidas. Es bien sabido que la conmutación rápida tiene un efecto directo en la mejora de la eficiencia; Sin embargo, la alta frecuencia de conmutación es la razón principal de la aparición de problemas de interferencia electromagnética (EMI) en los convertidores de potencia de modo conmutado. En la actualidad, la acción más directa para un controlador de puerta activo (AGD) consiste en el ajuste activo del transitorio de conmutación a través de la implementación de un circuito simple. Para evaluar su eficiencia, su rendimiento se compara con el controlador de puerta convencional (CGD) con perfil de conducción fijo. Los resultados muestran que la propuesta de AGD tiene la capacidad de aumentar la velocidad de conmutación mientras minimiza el stress. En este estudio se han diseñado y analizado diferentes controladores de puerta activa novedosos (como topologías de control en avance y de bucle cerrado). Para mejorar el balance existente entre la reducción de pérdidas y los problemas de EMI, todos los factores que afectan a las pérdidas y la EMI se evalúan y se consideran en las soluciones propuestas. Los desarrollos teóricos incluyen el análisis y desarrollo de los métodos de control propuestos, la simulación de la operación del control de conmutación del IGBT, y la validación experimental. Además de los aspectos técnicos de eficiencia y emisiones electromagnéticas, el estudio de costes también se ha considerado en los análisis de AGD. Los resultados muestran que los controladores de puerta propuestos son lo suficientemente eficientes y económicos como para permitir su uso en aplicaciones industriales reales [-]

Fecha Publicación: 2022-02-06T07:35:00.003-08:00

The trend in the development of power converters is focused on efficient systems with high power density, reliability and low cost. The challenges to cover the new power converters requirements are mainly concentered on the use of new switching-device technologies such as silicon carbide MOSFETs (SiC). SiC MOSFETs have better characteristics than their silicon counterparts; they have low conduction resistance, can work at higher switching speeds and can operate at higher temperature and voltage levels. Despite the advantages of SiC transistors, operating at high switching frequencies, with these devices, reveal new challenges. The fast switching speeds of SiC MOSFETs can cause over-voltages and over-currents that lead to electromagnetic interference (EMI) problems. For this reason, gate drivers (GD) development is a fundamental stage in SiC MOSFETs circuitry design. The reduction of the problems at high switching frequencies, thus increasing their performance, will allow to take advantage of these devices and achieve more efficient and high power density systems. This Thesis consists of a study, design and development of active gate drivers (AGDs) aimed to improve the switching performance of SiC MOSFETs applied to high-frequency power converters. Every developed stage regarding the GDs is validated through tests and experimental studies. In addition, the developed GDs are applied to converters for wireless charging systems of electric vehicle batteries. The results show the effectiveness of the proposed GDs and their viability in power converters based on SiC MOSFET devices. 
La tendencia en el diseño y desarrollo de convertidores de potencia está enfocada en realizar sistemas eficientes con alta densidad de potencia, fiabilidad y bajo costo. Los retos para cubrir esta tendencia están centrados principalmente en el uso de nuevas tecnologías de dispositivos de conmutación tales como, MOSFETs de carburo de silicio (SiC). Los MOSFETs de SiC presentan mejores características que sus homólogos de silicio; tienen baja resistencia de conducción, pueden trabajar a mayores velocidades de conmutación y pueden operar a mayores niveles de temperatura y tensión. A pesar de las ventajas de los transistores de SiC, existen problemas que se manifiestan cuando estos dispositivos operan a altas frecuencias de conmutación. Las rápidas velocidades de conmutación de los MOSFETs de SiC pueden provocar sobre-voltajes y sobre-corrientes que conllevan a problemas de interferencia electromagnética (EMI). Por tal motivo, el desarrollo de controladores de puertas es una etapa fundamental en los MOSFETs de SiC para eliminar los problemas a altas frecuencias de conmutación y aumentar su rendimiento. En consecuencia, aprovechar las ventajas de estos dispositivos y lograr sistemas más eficientes y con alta densidad de potencia. En esta tesis, se realiza un estudio, diseño y desarrollo de controladores activos de puerta para mejorar el rendimiento de conmutación de los MOSFETs de SiC aplicados a convertidores de potencia de alta frecuencia. 


Fecha Publicación: 2022-02-04T06:35:00.001-08:00


 School of Electrical & Electronic Engineering -2020

 A thesis submitted to the Nanyang Technological University in partial fulfilment of the requirement for the degree of Doctor of Philosophy 2020 

 Abstract: Driven by the ever-increasing energy demand and the desire for carbon footprint reduction, the power industry is under a wave of transformation from the current grid into the smart grid. As the trend of the grid transformation continues, a significantly high penetration level of renewable energy resources, in parallel with other emerging technologies such as the energy storage and electric vehicles, is to be expected. Since many types of renewables and energy storage devices, e.g., solar photovoltaic, batteries and supercapacitors, etc., are treated as DC sources, the multi-stage converter system is usually employed as the interface between the AC grid and DC networks. Specifically, the dual active bridge (DAB)-based two-stage AC-DC-DC converter is highly related to the distributed systems because of its advantages such as the high power density, soft switching properties, galvanic isolation and less passive components. Therefore, the stability and reliability of the two-stage AC-DC-DC converters are at the core of the distributed system operations. However, despite its control benefits, the two-stage AC-DC-DC converter system may suffer instability issues. This thesis aims to investigate and overcome the instability issues of the two-stage AC-DC-DC converter system. First, the existing primary stability criteria and stabilization methods for the non-isolated two-stage converter systems have been reviewed and summarized. The terminal impedances of the sub-converters are useful tools to determine the stability of the two-stage converter systems. The forbidden regions for the voltage-source and current-source systems have been discussed. To satisfy these stability criteria, the terminal impedances of the sub-converters should be modified via passive or active damping methods. The research gap for the isolated two-stage AC-DC-DC converter has been identified as well. To analyze the stability of the DAB-based two-stage AC-DC-DC converter, the full-order impedance model of the DAB converter is derived for the first time in this thesis. Since the high-frequency ac conversion stage of the DAB converter naturally violates the small ripple assumption of the traditional state-space modeling, the generalized averaging approach is applied for the DAB impedance derivation. The derived impedance model can provide fully continuous-time representations that are capable of describing the ac conversion stage of the DAB converter. Furthermore, based on the developed impedance model, the influences of the DAB circuit parameters on the stability of the two-stage converter are analyzed. The analysis results offer instructive implications to fine-tune the design rules of the DAB converters. Bearing the mind that the impedance model of the DAB converter is closely related to the modulation schemes, the impacts of three typical modulation methods on the DAB impedances are analyzed and compared. An interesting phenomenon is found that the open-loop impedances of Single Phase-Shift (SPS)-based and Dual Phase-Shift (DPS)-based DAB converters present the characteristics of the parallel-connected inductor and capacitor, while the open-loop impedance of Cooperative Triple Phase-Shift (CTPS)-based DAB converter presents the resistor characteristics. The optimal modulation scheme in terms of stability performance for the two-stage converter is pointed out. This can help engineers find a more stable modulation scheme of the DAB converter in practical cascaded applications.

Fecha Publicación: 2022-02-02T15:05:00.008-08:00

Development of AC/DC and DC/DC Converters Applied to DC Power Supply with Wide Range of Input Voltage

 A Dissertation Submitted to the School of Electrical and Electronic Engineering and the Graduate School of Yonsei University in partial fulfillment of the requirements for the degree of Doctor of Philosophy 

TaeHo Bang 

December 2018


This dissertation presents development of AC/DC and DC/DC converters applied to a DC power supply used for various electric devices from home appliances to electric vehicles. In general, the DC power supply consists of electromagnetic interference (EMI) filter for reducing the EMI noise, AC-DC converter to rectify the AC grid voltage into DC voltage and DC-DC converter to supply the power with the suitable voltage level for each device. The EMI filter is essential part of power supply because high speed switching of the converter devices causes undesirable EMI noise. The boost power factor correction (PFC) has widely used for the AC-DC converter because of its simple structure and low cost. In addition, the ability to cope with various AC grid voltages and conditions in different countries is becoming important for PFC converter topologies from the industrial point of view. Meanwhile, full-bridge DC-DC converter is one of the most frequently used topologies in electric vehicle when electrical isolation is required. Isolated DC-DC full-bridge converters are suitable for low DC-DC converter (LDC) which converts high input voltage of the battery into low output voltage level for suppling the power to load of the electrical vehicle. The efficiency of DC-DC converter in electric vehicle are highly related with overall performances including range distance, weight and charging time. Then, improving efficiency without much additional component becomes very important in converter topologies used in electric vehicle. The buck cascaded buck-boost (BuCBB) PFC converter and isolated full-bridge (FB) converter are studied in this dissertation, respectively. 

 First, the BuCBB PFC converter which operates in wide input voltage range to cope with various grid conditions is developed. The converter can operate in buck or boost mode according to the peak value of input voltage. The converter parameters are properly determined to endure voltage and current stress in all operating ranges. In addition, the EMI filter is used to reduce the high frequency switching noise and guarantee continuous input current in buck mode operation. In addition, switching loss is reduced in all operation range by applying zero-voltage-transient pulse-width-modulation (ZVT-PWM) method. In particular, the power factor (PF) depending on the operation modes of the PFC converter including EMI filter is derived with associated mathematical equations in buck and boost mode, respectively. The performances of proposed PFC converter with wide range of input voltage are evaluated by the simulation and experimental test including PF and input current harmonics in all operating ranges. Finally, the efficiency of proposed PFC converter is compared with that of a conventional buck cascaded buck-boost PFC converter in various conditions. And then, a novel control method for FB converter by using the combined phase-shifted and asymmetric pulse-width-modulation (APWM) method is proposed. It reduces the peak and DC offset values of the input-side current of converter. Then, the overall efficiency is consequently improved by reduced the switching losses in its input-side. Moreover, the zero-voltage switching (ZVS) conditions of switches are satisfied in all operating ranges. The phase-shifted duty ratios corresponding to the output currents of converter are optimally selected based on the loss model analysis. Also, the operational features characterized by the proposed phase-shifted asymmetric pulse-width-modulation (PS-APWM) method are investigated under both the continuous and discontinuous current modes of converter. Then, the effectiveness of proposed PS-APWM method is verified with the simulation and practical hardware experimental results. In particular, the experimental test is carried out in a light load condition. Finally, the efficiency of FB converter controlled by the proposed PS-APWM method is compared with that by the conventional phase-shifted or APWM method, which has been separately applied.



DOWNLOAD: https://www.mediafire.com/file/f0v5mkub38680y5/Development+of+ACDC+and+DCDC+Converters+Applied+to+DC+Power+Supply+with+Wide+Range+of+Input+Voltage.pdf/file

Fecha Publicación: 2022-01-27T18:23:00.001-08:00


Title: Rezonanční izolující měnič s GaN tranzistory 

Other Titles: Resonant insulating converter with GaN transistors 

Authors: Soukup, Dominik
 Advisor: Jára Martin, Ing. Ph.D. Referee: Štěpánek Jan, Ing. Ph.D.
 Issue Date: 2021 
Publisher: Západočeská univerzita v Plzni

Předkládaná diplomová práce se věnuje návrhu a realizaci rezonančního izolujícího měniče s GaN tranzistory. V práci je uvedeno stručné porovnání polovodičových materiálů a rezonančních měničů. Dále se práce zabývá samotným návrhem měniče, který zahrnuje výběr a dimenzování polovodičových součástek, návrh budícího obvodu, mechanický koncept a následnou realizaci. Závěrečná část práce se věnuje oživení a testování prototypového měniče.

The presented diploma thesis deals with the design and implementation of a resonant isolating transducer with GaN transistors. The paper presents a brief comparison of semiconductor materials and resonant converters. Furthermore, the work deals with the design of the converter, which includes the selection and dimensioning of semiconductor components, the design of the excitation circuit, the mechanical concept and subsequent implementation. The final part of the work is devoted to the recovery and testing of a prototype converter.

Fecha Publicación: 2022-01-23T16:48:00.001-08:00

부하 임피던스 변동을 고려한
공진형 전력 변환 시스템의
4 단자 네트워크 설계

서울대학교 대학원


정 의 훈

Engineering PhD thesis Considering load impedance fluctuations of resonant power conversion system 4-terminal network design 
 Seoul National University Graduate 
School Department of Electrical and Information Engineering
By  Jeong Eui-Hoon


Resonant power conversion systems have been widely used for high-frequency power conversion due to the advantage of low switching losses in inverter circuits. Such a system structure has been adopted in various fields such as battery charging, wireless power transmission, plasma driving system, and etc. Resonant power conversion systems operate very efficiently under one driving operation condition, but performance is easily degraded by system variations. In this dissertation, a systematic method for designing a resonant network, which is a key element of a resonant power conversion system, is proposed. The degree of design freedom of a two-port network is analyzed based on the general and mathematical model. This dissertation presents methods utilize the design freedoms to shape the input impedance trajectories to the desired way or to compress the input impedance variations to a certain value when the load impedance varies in a certain range. Based on this theoretical background, a resonant power conversion system with robust characteristics against load impedance is constructed. The proposed method is applied to design the wireless power transfer system that has a robust output characteristic against coil coupling variation. In addition, the proposed method is used to construct a high-frequency power conversion system that maintains impedance matching even with a wide range of load impedance variations. For the design examples, simulation and experimental results are presented to verify the effectiveness and the superiority of the proposed method. 

Fecha Publicación: 2022-01-19T17:04:00.004-08:00


Fecha Publicación: 2022-01-12T19:00:00.004-08:00

Autor: Edemar de Oliveira Prado Orientador: José Renes Pinheiro 

RESUMO Esta dissertação apresenta um modelo analítico para auxiliar no cálculo de perdas por comutação e uma metodologia de seleção de MOSFETs que operam tensões de bloqueio maiores que 100 V. O modelo foi desenvolvido com base em conceitos físicos e elétricos da estrutura FET, considerando as não linearidades da capacitância Miller em função da variação de tensão, presentes principalmente em MOSFETs fabricados para operar tensões acima de 100 V. Resultados de simulação e experimentais que validam o modelo foram obtidos, considerando a faixa de frequência de 1 - 300 kHz, onde o limite de operação do gate driver foi atingido. O modelo proposto foi comparado a modelos de cálculo de perdas frequentemente utilizados na literatura, onde se observou que os demais modelos utilizados apresentaram aumento no erro relativo para frequências acima de 50 kHz. Sistemas de transferência de calor são analisados e discutidos. O modelo de cálculo de perdas proposto é utilizado no desenvolvimento de uma análise comparativa entre as tecnologias de MOSFET convencional de Silício, superjunção, SiC e GaN. O impacto das capacitâncias parasitas, temperatura de junção, resistências intrínsecas a estrutura, frequência de comutação e níveis de potência em cada tecnologia são analisados. Áreas de tendências de aplicação são definidas para cada tecnologia com base nos rendimentos em função da frequência e da potência.


Fecha Publicación: 2022-01-08T05:02:00.003-08:00



Fecha Publicación: 2022-01-07T18:06:00.004-08:00

Power Electronics Group of TalTech This video was recorded during a seminar co-organized by the Doctoral School of Energy and Geotechnology III, TalTech, and IES/PELS/PES/IAS Joint Societies Chapter, IEEE Estonia Section. The talk was given at the Department of Electrical Power Engineering and Mechatronics, Tallinn University of Technology, Estonia, on November 30, 2021.

Fecha Publicación: 2022-01-05T18:08:00.008-08:00

Inductor and Capacitor Response Inductor and Capacitor Response Ideal Switch and Switching Function Principles of static power conversion , switching cell structure , DC-DC converter , AC-DC converter , DC-AC converter POWER ELECTRONICS PROF. YONGSUG SUH - CHONBUCK NATIONAL UNIVERSITY - KOREA OPEN COURSEWARE-PART4

Fecha Publicación: 2022-01-01T16:02:00.005-08:00


 Los inversores multinivel se utilizan de forma habitual en aplicaciones de gran potencia, pero la aplicación de las topologías multinivel en la generación fotovoltaica de pequeña potencia presenta algunas ventajas de interés. Se propone una topología de inversor fotovoltaico monofásico de inyección a red sin transformador, basada en las topologías multinivel, llamada NPC+GCC. Esta topología presenta características de gran interés para su uso como inversor sin transformador directamente conectado a la red eléctrica. Se estudia su tensión de modo común, y cómo esta genera una corriente de derivación capacitiva que se mantiene muy por debajo de los límites permitidos por la normativa. La topología NPC+GCC permite la conexión de dos generadores fotovoltaicos en su entrada, sobre los que efectuará una búsqueda del punto de máxima potencia de manera totalmente independiente y con un elevado rendimiento y fiabilidad, ya que no utiliza convertidores conectados en cascada para realizar esta función.

Fecha Publicación: 2021-12-27T16:45:00.006-08:00


3-phase Dynamic Voltage Restorer with Switching Cell Structured Direct AC-AC Converter Using Interphase Voltage* Hyeongmin Lee School of Electronic and Electrical Engineering Graduate School, Kyungpook National University Daegu, Korea (Supervised by Professor Heung-Geun Kim) 

 (Abstract) Instantaneous voltage sag account for the largest proportion of various grid accidents, and the economic losses resulting from them are enormous. To solve this problem, various dynamic voltage restorer(DVR) systems are being researched and developed. Most of these are back-to-back(BTB) types and energy storage(ES) types. Since the BTB type uses the distribution voltage as a voltage source, it can be compensated continuously without a separate storage device, but energy conversion loss occurs because energy conversion must be performed in two or more stages. Also, in order to secure the DC-link voltage, the controller must be complicatedly configured. The ES type utilizes an extra energy storage device and uses it as a voltage source. This results in energy conversion in one stage, resulting in small conversion losses. However, since the unit cost of the energy storage device is high, there is a disadvantage that a lot of cost is incurred to construct the system. Also, due to the capacity limitations of energy storage devices, the compensation time is limited. If additional storage devices are configured to extend the compensation time, the cost will be higher, and this will determine the performance of the system. In this paper, a DVR system consisting of a direct AC-AC converter with a switching cell structure and using an interphase voltage source is presented. The switching cell structure overcomes the current commutation problem, which is a disadvantage of the conventional AC switch, and can prevent damage to the switch due to the short circuit and open of the conventional switch leg. In addition, it can be operated with a high switching frequency because it can be configured as a diode with a fast reverse recovery time instead of a body diode with poor performance. This can reduce the volume and unit cost of passive filters, which are costly in the system configuration. And by using the interphase voltage as a voltage source, it overcomes the disadvantage that the compensation range of the DVR using an ac-ac converter is limited to 50%. This can also compensate for phase jump situations. Compared with the BTB type, the efficiency is good due to energy conversion in one stage, and the time to secure the DC-link voltage is not required, so the dynamic characteristics are better. In addition, control is simple because it is driven through DC reference. Compared with the ES type, there is no limit to the storage device, so the compensation duration is long and the system configuration is economical. Above all, unlike the two conventional compensators that use a voltage source inverter(VSI), the system reliability is excellent and there is no need to apply a bulky and lossy filter. Finally, to prove the feasibility of this paper, we performed a simulation and directly configured the hardware to prove that it is compensable under various voltage sag situations.


Fecha Publicación: 2021-12-23T15:49:00.004-08:00

Conheça a história de Ildo Bet, um pioneiro no segmento de energia que é um símbolo da inovação tecnológica no país ENGENHEIRO desenvolvedor da fonte de alimentação do microcomputador: Ildo Bet, engenheiro eletrônico, professor universitario e CEO da PHB Solar, a empresa produtora das fontes das urnas eletrônicas do país. Desde 1984, ano de fundação da PHB, uma busca por inovação e qualidade, com seriedade e desenvolvimento tecnológico brasileiro, foram fatores notáveis ​​e importantes na trajetória da PHB Solar. Desta maneira, foi o primeiro fabricante de inversores solares a ser certificada pelo INMETRO no Brasil, atuando na coordenação e elaboração de normas reguladoras e criando forma singular, um laboratório completo para testes e manutenção dos seus próprios produtos. Sempre à frente, a PHB Solar é uma indústria 100% nacional com pioneirismo e competência tecnológica, desenvolvendo soluções para a Geração Distribuída como um todo. A engenharia da PHB oferece respostas rápidas e não depende de uma consulta internacional, sendo uma empresa precursora no mercado de energia solar. 

Edmond Tech Elementar para o seu negócio Financial Services Barueri, São Paulo

Fecha Publicación: 2021-12-04T08:54:00.003-08:00

PARTICIPAÇÃO NO WEBINAR "Sistema Elétrico de Potência: Mudanças, desafios e oportunidades". O webinar contó com uma palestra ministrada pelo Professor Dr. Thiago Rocha da UFRN, além de uma mesa redonda composta pelo Engenheiro Igor Chianca, o Pesquisador Thales Queiroz e pela Engenheira Victória Botelho.Capítulo Estudantil PELS/IAS do Ramo IEEE UFRN BRASIL

Fecha Publicación: 2021-12-01T12:03:00.002-08:00


In power electronics designs, the evaluation and prediction of potential fault conditions on semiconductors is essential for achieving safe operation and reliability, being short circuit (SC) one of the most probable and destructive among the failures. It can occur externally to the power converter by shortening the load, or internally due to failures on galvanic isolations, stress on passive components, or even in the power semiconductors themselves. Silicon (Si) based power semiconductors have been extensively investigated with regards to their SC capability, although there is still on-going research as their design is being pushed closer to theoretical limits. Recent improvements on Wide-Bandgap (WBG) semiconductors such as Silicon Carbide (SiC) and Gallium nitrite (GaN) enable power electronic designs with outstanding performance, reshaping the power electronics landscape. In comparison to Si, SiC and GaN power semiconductors physically present smaller chip areas, higher maximum internal electric fields, and higher current densities. Such characteristics yield a much faster rise of the devices internal temperatures, worsening their SC performance if compared to Si.

Fecha Publicación: 2021-11-26T05:32:00.004-08:00


Esta dissertação de mestrado tem como proposta o desenvolvimento de um sistema de gerenciamento de carga de um banco de 16 baterias de chumbo ácido, com capacidade de carga de 7Ah, comumente utilizado em Fontes Ininterruptas de Energia (UPS). Este sistema visa garantir que estas baterias cheguem a um estado de carga completo e de forma mais rápida que a convencional. Para isto, foi escolhido fazer a modificação do método de carga de corrente pulsada, com o objetivo de reduzir problemas inerentes do método tomado como base, quando ocorre o intervalo de retirada de energia da bateria, tais como: elevação da tensão do barramento ao retornar a energia para ele, ou, dissipar esta energia em uma resistência, o que acarreta em baixa eficiência do sistema. Para o desenvolvimento do sistema de carga sugerido foi escolhido o conversor estático Full-Bridge Isolado com modulação Phase Shift. Foi feita a modelagem simplificada deste conversor, para a implementação do controle digital, assim como o desenvolvimento prático do mesmo em laboratório. São apresentados os resultados de simulação e experimentais para validar o método.