Projeto de um transformador de potência de média frequência (kHz)- Pedro Filipe Francisco Reis-Dissertação para obtenção do Grau de Mestre em Engenharia Eletrotécnica e de Computadores

 

Projeto de um transformador de potência de média frequência (kHz) Pedro Filipe Francisco Reis

 Dissertação para obtenção do Grau de Mestre em Engenharia Eletrotécnica e de Computadores

 Resumo 

Neste trabalho são apresentadas as equações necessárias para realizar o projeto de um transformador. São elaboradas considerações acerca da escolha do material do núcleo e dos enrolamentos de forma a minimizar os problemas introduzidos pelo caracter de média frequência do transformador. São calculados os parâmetros do transformador que se pretende construir tendo em conta as especificações iniciais. É apresentado o modelo do transformador e os seus parâmetros são estimados a partir de equações teóricas. Os parâmetros são estimados também recorrendo a um analisador de redes e ensaiando o transformador (ensaios em circuito aberto, curto circuito e carga). Um mapa de rendimento do transformador é apresentado. É elaborada uma simulação de simulink do transformador, usando os parâmetros estimados nos ensaios, de forma a validar os resultados obtidos.

 Abstract 

In this paper are described the equations needed to design a transformer. Some considerations about the choice of the core and windings materials are made, due to the medium frequency character of the transformer and are presented solutions to the problems. The parameters of the prototype to build are calculated and the prototype is mounted. The model of the transformer is presented and its parameters are estimated theoretically, with an impedance meter and testing the transformer in open circuit, short circuit and load condition. An efficiency map of the transformer is made. A Simulink simulation of the transformer, using the parameters obtained in the tests, is made to validate the results obtained before.

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PROGRAMA COMPUTACIONAL PARA PROJETO DE TRANSFORMADORES UTILIZADOS EM FONTES DE ALIMENTAÇÃO CHAVEADAS-CLÁUDIO LUÍS EBERT-UNIVERSIDADE FEDERAL DE SANTA CATARINA-BRASIL

 PROGRAMA COMPUTACIONAL PARA PROJETO DE TRANSFORMADORES UTILIZADOS EM FONTES DE ALIMENTAÇÃO CHAVEADAS

 DISSERTAÇÃO SUBMETIDA À UNIVERSIDADE FEDERAL DE SANTA CATARINA PARA OBTENÇÃO DO GRAU DE  MESTRE EM ENGENHARIA ELETRICA. CLÁUDIO LUÍS EBERT FLORIANÓPOLIS, AGOSTO DE 1997. 

 RESUMO 

Este trabalho apresenta uma metodologia de projeto de transformadores para uso em freqüência elevada, utilizados em fontes de alimentação chaveadas. A partir de estudos analíticos sobre os principais parâmetros envolvidos no projeto, a metodologia definida é implementada através do desenvolvimento de um programa computacional. A implementação de tal programa é feita tomando como suporte básico o software Borland Delphi, que combina uma interface gráfica, um compilador Pascal e um banco de dados. Dentre os objetivos deste trabalho destaca-se a otimização conjugada à facilidade no projeto do transformador, além da precisão e da possibilidade de se considerar parâmetros que normalmente são desprezados, muito embora importantes. O programa implementado é composto por telas de projeto, telas para seleção de materiais, um algoritmo matemático e bancos de dados. Dentre os bancos de dados destacam-se o dos materiais ferrimagnéticos (ferrites) de alguns fabricantes, e o dos núcleos, onde tem-se todas as características necessárias do mesmo. Desta forma o usuário dispõe rapidamente de informações decisivas no projeto e que, dada a estrutura do programa, podem ser completadas e atualizadas. Para a verificação dos projetos feitos via programa computacional, montou-se um inversor ponte completa, onde o transformador tem uma onda quadrada simétrica em seu enrolamento primário. A partir dos resultados obtidos experimentalmente comprova-se a eficácia do programa, a facilidade no projeto do transformador, bem como um funcionamento adequado do mesmo, validando desta forma a metodologia de projeto adotada.

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단상 반도체 변압기의 출력 전력 전향 보상을 통한 과도 응답 개선 = A Transient Response Improvement by Output Power Feedforward Compensation for Single-Phase Solid-State Transformer--Bang Jaehyeon Department of Electrical Engineering Graduate School of Konkuk University-

 

ABSTRACT 

A Transient Response Improvement by Output Power Feedforward Compensation for Single- Phase Solid-State Transformer Bang Jaehyeon

Department of Electrical Engineering Graduate School of Konkuk University 

This paper proposes a output power feedforward compensation method for Dual Active Bridge(DAB) converter based 2-stage single-phase solid-state transformer. Solid-State Transformer(SST) is a bidirectional power converter which is capable of electrical isolation between input and output stage. SST enables the connection of DC power sources such as PV panels, Fuel Cells, and ESS much easier compared with conventional transformers by forming DC bus. Each stage of SST composes of AC-DC converter and isolated DCDC converter. Especially, DAB converter, which has advantages of galvanic isolation with high frequency(HF) transformer, facility of bidirectional operation, and ease of realizing soft switching, is regarded as one of the most fundamental elements in SST. In contrast to conventional PWM converters, DAB converter controls output power by adjusting the phase shift between output voltage of two H-bridges. 70 For designing output voltage feedback controller, small signal model of DAB converter derived from output power equation with phase reference DAB d is applied. Also, bandwidth limitation caused by 120Hz power ripple in DC-link voltage controller, which induces unequal input and output voltage ratio compared with turns ratio of HF transformer, is described. For eliminating this voltage decoupling with current peak rising of leakage inductor, output power-based feedforward compensation method for DC-link voltage controller is proposed. Furthermore, the effectiveness of feedforward term is identified by confirming the reduction in output impedance of converter based on small signal model. In comparison of experimental results, proposed method verified the improvement in transient DC-link voltage decrease by 24.8% and leakage inductor current peak increase by 27.7% during load step input. It also yielded improvement in DC-link voltage increase by 23% while unload transient. Keyword : Solid-State Transformer(SST), Dual Active Bridge(DAB) converter

ORIGINAL LINK: http://www.riss.kr/search/detail/DetailView.do?p_mat_type=be54d9b8bc7cdb09&control_no=491adc48c7a349efffe0bdc3ef48d419&keyword=sst%20solid%20state%20transformer

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배터리 에너지 저장 시스템에 사용되는 전력 변환 시스템의 디지털 제어 Digital Control of Power Conversion System Used in Battery Energy Storage System-Wan, Kim Department of Marine Electronic, Communication and Computer Engineering, Graduate School, Mokpo National Maritime University

 Digital Control of Power Conversion System Used in Battery Energy Storage System

 BY Wan, Kim 

Department of Marine Electronic, Communication and Computer Engineering, Graduate School, Mokpo National Maritime University (Supervised by Professor : Kwang-Woon, Lee) 

ABSTRACT

To operate the electric power supply system more efficiently and stably, the utilization of battery energy storage system (BESS) is increasing. By using BESS, the residual electrical energy can be stored at low power demand times and the stored electrical energy can be released at high power demand times. Therefore, BESS can counteract the frequency fluctuation of the electric power system due to load variations. In addition, BESS can be utilized to make stable operation of renewable energy sources such as photovoltaic power generation and wind power generation. An electric power conversion system is used in BESS and it consists of bidirectional dc-to-dc converters and dc-to-ac inverters; the role of the bidirectional dc-to-dc converters is to charge and discharge the batteries and the dc-to-ac inverters are employed for grid connected energy conversion. A digital control is generally used to control the electric power conversion system of BESS and typical digital control strategy is based on the small signal model of the electric power conversion system. However, it is known that the small signal model based digital control is vulnerable to the operating point variations because the small signal model is obtained at a specific operating point. The purpose of this paper is to present a stable digital control strategy for the electric power conversion system of BESS, insensitive to operating point variations. This paper presents a design method for the power conversion system of BESS, wherein an average model based control is employed to solve the problem of the conventional small signal model based control. To compare the performance of the proposed control method with the conventional small signal model based controller, the single input and single output (SISO) controller design tool of MATLAB is utilized. For this purpose, the small signal model of the bidirectional dc-to-dc converter is derived and the SISO tool based digital controller is designed to obtain the specific bandwidth and phase margin. The time and frequency domain responses of the proposed average model based controller are obtained using a PSIM software and the obtained results are compared with the responses of the conventional small signal model based controller to show the improved transient control performance of the proposed method. To prove the effectiveness of the proposed method, the proposed control method is implemented using a digital signal processor (DSP).

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A comprehensive design approach for a three-winding planar transformer Shenli Zou1 Chanaka Singhabahu2 Jianfei Chen2 Alireza Khaligh2

A comprehensive design approach for a three-winding planar transformer 

Shenli Zou1 Chanaka Singhabahu2 Jianfei Chen2 Alireza Khaligh2 

1Electric Power Conversion, Rivian Automotive,

Inc, USA

2Maryland Power Electronics Laboratory (MPEL),

Department of Electrical and Computer

Engineering, Institute for Systems Research,

University of Maryland, College Park, Maryland,

USA

 Abstract 

In this paper, a new three-winding planar transformer design with the integrated leakage inductor is proposed for a triple-active-bridge converter. It enables two output voltage levels: a high voltage (HV) output port and a low voltage (LV) output port. The primary and secondary windings are split unevenly in both side legs while the tertiary winding is connected in parallel. The unique winding configuration enables: (i) enhanced efficiency with low volume; and (ii) suppressed parasitic capacitances. Detailed transformer reluctance and loss models are developed in the design process. The core geometry is optimized using a reluctance-model-based mathematical computation. Moreover, comprehensive high-fidelity simulations are conducted to analyse the trade-offs among parasitic capacitances, losses, and inductances. The customized core and the non-overlapping winding boards are assembled, characterized, and tested under various power flow conditions.

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https://ietresearch.onlinelibrary.wiley.com/doi/full/10.1049/pel2.12261