Transformer Shielding Technique for Common Mode Noise Reduction in Switch Mode Power Supplies Yuchen Yang -Virginia Polytechnic Institute and State University

Transformer Shielding Technique for Common Mode Noise Reduction in Switch Mode Power Supplies Yuchen Yang
 Thesis submitted to the Faculty of the Virginia Polytechnic Institute and State University in partial fulfillment of the requirements for the degree of Master of Science in Electrical Engineering.

(Abstract)
 Switch mode power supplies are widely used in different applications. High efficiency and high power density are two driving forces for power supply systems. However, high dv/dt and di/dt in switch mode power supplies will cause severe EMI noise issue. In a typical front-end converter, the EMI filter usually occupies 1/3 to 1/4 volume of total converter. Hence, reducing the EMI noise of power converter can help reduce the volume of EMI filter and improving the total power density of the converter. For off-line switch mode power supplies, DM noise is dominated by PFC converter. CM noise is a more complicated issue. It is contributed by both PFC converter and DC/DC converter. While many researches have focused on reducing CM noise for PFC converter, the CM noise of DC/DC converter still remains a challenge. The main objective of this thesis is provide a solution to have best CM noise reduction for DC/DC converters. The shielding concept and balance concept are combined to propose a novel balance double shielding technique. This method can have an effective CM noise reduction in the circuit level. In addition it is easy to design and implement in the real production. The balance condition is easily controlled and guarantees effective CM noise reduction in mass production. Then, a novel one-layer shielding method for PCB winding. transformer is provided. This shielding technique can block CM noise from primary side and also cancel the CM noise from secondary side. In addition, shielding does not increase the loss of converter too much. Furthermore, this shielding technique can be applied to matrix transformer structure. For matrix transformer LLC converter, the inter-winding capacitor is very large and will cause severe CM noise problem. By adding shielding layer, CM noise has been greatly reduced. In addition, by modifying the secondary winding, the loss on shielding layer is minimized and experiments show that the total efficiency of converter has almost no impact. Furthermore, although this thesis uses flyback and LLC resonant converter as example to demonstrate the concept, the novel shielding technique can also be applied to other topologies that have similar transformer structure.

 LINK ORIGINAL WEB
https://vtechworks.lib.vt.edu/bitstream/handle/10919/49263/Yang_Y_T_2014.pdf?sequence=1

High Frequency-Link Cycloconverters for Medium Voltage Grid Connection -Shattock, Nicholas -PhD thesis, University of Nottingham.

High Frequency-Link Cycloconverters for Medium Voltage Grid Connection Nicholas Shattock BEng. (Hons) Thesis submitted to the University of Nottingham for the degree of Doctor of Philosophy 

Abstract
 As the deployment of renewable generation increases in the worldwide electrical grids, the development of distributed energy storage becomes more and more of an essential requirement. Energy storage devices connected at Medium Voltage allows for much higher powered deployments and this Ph.D. will focus on the power converter used to interface the energy storage device to the electrical grid. Multi-level converters can be used to provide this interface without huge ltering requirements or the need of a Low Frequency step up transformer. However traditional Multi-level converter topologies require a large number of electrolytic capacitors, reducing the reliability and increasing the cost. Multi-level converters constructed from a Cycloconverter Topology do not require any additional electrolytic capacitors, however the High Frequency transformer, used to provide isolation has to be considerably larger. This Ph.D. will investigate a novel hybrid converter topology to provide an interface between an energy storage device, such as a super-capacitor or battery, to the Medium Voltage grid, designed for high reliability and power density. This topology is called The Hybrid Cycloconverter Topology and is based on a Cycloconverter Topology connected to an auxiliary 3-Phase VSI. A comprehensive simulation study is carried out to investigate the semiconductor losses of this novel converter topology and compared against two alternative topologies. An experimental converter is constructed to validate the theory of operation and to justify its e ectiveness.

 LINK ORIGINAL
http://eprints.nottingham.ac.uk/14205/1/index2.pdf
LINK ALTERNATIVO
http://www.mediafire.com/file/yeyc074pn02azbq/High_Frequency-Link_Cycloconverters.pdf

Manual de Engenharia para Sistemas Fotovoltaico - Cresesb - Cepel - JOÃO TAVARES PINHO- MARCO ANTONIO GALDINO-BRASIL-2014

LINK ORIGINAL DE ACCESO LIBRE EN LA WEB
http://www.cresesb.cepel.br/publicacoes/download/Manual_de_Engenharia_FV_2014.pdf
LINK ALTERNATIVO
http://www.mediafire.com/file/uqaf4ruq81fuwm5/Manual_de_Engenharia_FV_2014.pdf

Communication Circuits: Analysis and Design by Kenneth K. Clarke

Communication Circuits: Analysis and Design by Kenneth K. Clarke ESTUDIE CIRCUITOS ELECTRONICOS III CON ESTE LIBRO EN LA FACULTAD DE INGENIERIA ELECTRÓNICA DE LA UNIVERSIDAD NACIONAL MAYOR DE SAN MARCOS SIENDO MI PROFESOR EL ILUSTRE PROF. Carlos Sanchez Tarnawiecki hoy Profesor del Postgrado at Universidad Nacional Mayor de San Marcos

LINK ORIGINAL EN LA WEB
http://www.samanezehn.com/ketab2.pdf
LINK ALTERNATIVO
http://www.mediafire.com/file/a937ig695iiah4a/communication_circuits.pdf

Quasi Z-Source AC-AC converter system connected in series With Dynamic Voltage Restorer(DVR) capability Jun-Hyun Eom - Department of Electrical Engineering Graduate, School Chonnam National University-SOUTH KOREA

동적전압보상 기능을 갖는 출력이 직렬 결합된 Quasi Z-소스 AC-AC 컨버터
 Quasi Z-Source AC-AC converter system connected in series With Dynamic Voltage Restorer(DVR) capability Jun-Hyun Eom
 Department of Electrical Engineering Graduate, School Chonnam National University (Supervised by Professor Young-Cheol Lim)

(Abstract)
 Recently, different with the conventional load, the present load devices such as computers, Automated production equipments, precision electronic devices are very sensitive to the power quality. These load devices sensitive to the power quality are increasing sharply and people are paying more and more attention to the AC-AC power conversion devices like instantaneous voltage-compensators, phase-shifters, electronic transformer which are installed in the side of power system or consumers. Similarly, the AC chopper, PWM AC-AC converter, matrix converter and Z-Source AC-AC converter also belong to the AC-AC power conversion devices referred above. among these devices, due to the latest research method, the Z-Source AC-AC converter has quite simply structure and control method and is possible to boost output voltage in phase and boost or buck output voltage out of phase with respect to input voltage.

Nevertheless, since the Z-Source AC-AC converter operates in DCM (Discontinuous Current Mode), stress of the elements is bigger compared with the case of CCM(Continuous Current Mode) and it's very disadvantageous viewed from the waveform. It is probable to solve the problems referred above by Quasi Z-Source AC-AC converter. However, the operation of buck mode is impossible, even though it's possible to boost or buck the output voltage out of phase and boost the output voltage in phase.

In this study, a single-phase quasi Z-source AC-AC converters with a series connection of the output terminals is proposed. The proposed system has configuration that the input terminals of two quasi Z-source AC-AC converters are connected in parallel and its output terminals are connected in series. for output of in-phase buck mode with respect to the input ,the intersection switching control is presented and the current flow in both of the out phase mode and in phase mode and the output voltage's forming process was shown.

In addition, a DVR(Dynamic Voltage Restorer) though using a single-phase quasi Z-source AC-AC converter connected with the output terminals in series is proposed. In general, among the problems which cause the lower quality, the Voltage Swell or Voltage Sag could be the major one which brings great influence to the consumers with high frequency and sensitive load. The Voltage Swell which is the increasement of the supply voltage's magnitude in duration of 0.5∼30[cycles] while the voltage magnitude is 1.1∼1.8[p.u] of nominal voltage and the Voltage Sag which is the drop of the supply voltage's magnitude in duration of 0.5∼30[cycles] while the voltage magnitude is 1.1∼1.8[p.u] of nominal voltage can lead to the accidents happening in most of the nearby distribution circuits. Such Voltage Swell or Voltage Sag causes the misoperation or suspension of work and bring about Nevertheless, since the Z-Source AC-AC converter operates in DCM (Discontinuous Current Mode), stress of the elements is bigger compared with the case of CCM(Continuous Current Mode) and it's very disadvantageous viewed from the waveform.

It is probable to solve the problems referred above by Quasi Z-Source AC-AC converter. However, the operation of buck mode is impossible, even though it's possible to boost or buck the output voltage out of phase and boost the output voltage in phase.
In this study, a single-phase quasi Z-source AC-AC converters with a series connection of the output terminals is proposed.

LINK ORIGINAL EN LA WEB
http://ocean.kisti.re.kr/downfile/volume/kipe/JRJJC3/2013/v18n4/JRJJC3_2013_v18n4_322.pdf