“SE SEUS PROJETOS FOREM PARA UM ANO,SEMEIE O GRÂO.SE FOREM PARA DEZ ANOS,PLANTE UMA ÁRVORE.SE FOREM PARA CEM ANOS,EDUQUE O POVO.”

“Sixty years ago I knew everything; now I know nothing; education is a progressive discovery of our own ignorance. Will Durant”

OBRIGADO DEUS PELA VIDA,PROTEGENOS E GUARDANOS DE TODO MAL


AUTOR DO BLOG ENG. ARMANDO CAVERO MIRANDA SAO PAULO BRASIL

domingo, 24 de setembro de 2017

Transformer comparison by core form and winding structure Woong-Jae Kang Department of Electrical Engineering Graduate School Gyeongsang National University




Flyback Transformer Performance by Core and Winding Structure 

 Abstract 
Transformer comparison by core form and winding structure Woong-Jae Kang Department of Electrical Engineering Graduate School Gyeongsang NationalUniversity 

Supervised by Professor Hwi-Beom Shin
The leakage inductance of the flyback transformer causes the voltage spike in the MOSFET switch. The RCD snubber is typically used to reduce the voltage spike. The current method change the transformer winding structure to reduce effect of leakage inductance, because it is difficult to reduce influence of leakage inductance any more in circuit improvement. In this paper, it show the change for voltage spike and ringing depending on winding structure and core form of transformer.
LINK
http://www.mediafire.com/file/6kj45ksizg7z5m2/FLYBACK_PLANO.pdf

terça-feira, 5 de setembro de 2017

Development of Photovoltaic Inverter used Grid-Connected Distributed Power Jeong-Do Kim Department of Electrical Engineering Graduate School Pukyong National University









Development of Photovoltaic Inverter used Grid-Connected Distributed Power 
Jeong-Do Kim 

Department of Electrical Engineering Graduate School Pukyong National University 

Abstract

This paper relates to grid-connected single-phase inverter system, the proposed system is a gate pulse signal was added to the active auxiliary resonant circuit in the bridge arm of a conventional grid-connected single-phase half-bridge inverter, main switch is modulated by the SPWM method by configuring so that the, take a feature that can control the multi-phase alternating current can be used in the batch phase inverter. And active by the secondary resonance also work during the snubber circuit a dead time period, soft switching is possible because it actually turns a basic switch in the on state-off and resonant operation after turning the other main switch-which was applied to the whole of the gate signal have the characteristic. Further, when the conventional program is shorter than the width of the gate pulse signal active auxiliary resonant snubber operation time in the operation in the hard switching to occur even if the H, L is the reverse of the gate pulse signal. This power supply is in reversal of the power supply circuit is a short circuit may possibly be damaged since. To prevent this, this paper has set the ARCP operation time and modulation rate settings and processes the pulse of the gate pulse signal reversal was the program not to occur. 114 Further, as the main switch is in the off state to the time when the other switch is turned on, and the dead time is a hard switching method in case of the conventional method to sequence the switching pattern 1.5[μs], While for setting the dead time of the soft switching system with 2.0[ms], For this paper the sequence switching patterns applied to the soft-switching method is 4.0[μs] because the pulse width of the hard-switched at the same modulation rate and time to get a high density to suppress the resonant inductor current as a whole small effect of improving the efficiency have. Running a soft switching operation by the switching pattern sequence scheme applied to the paper, it is possible to suppress the surge voltage and the surge current, the generation of noise of the device is reduced as compared to the effect of the hard switching method.

LINK:
http://www.mediafire.com/file/1dyn6jy9g5767gj/PHOTOVOLTAIC_INVERTER.pdf