LED lighting control driver design and development of the 12V‐12W class using the voltage controlled ring oscillator - Ki-Soo Kwon Department of Electronic Engineering Graduate School Yeungnam University

LED lighting control driver design and development of the 12V‐12W class using the
voltage controlled ring oscillator

Ki-Soo Kwon
Department of Electronic Engineering
Graduate School
Yeungnam University


Abstract
This paper presents a Pulse Width Modulation (PWM) controller and circuits for the high power LED (Light Emitting Diode) driver. The controller is available for the remote control through four major operation modes of ON, OFF, Emergency and Power saving using the serial communication. The entire driver circuits use a DC‐DC converter such a Boost topology with dimming, current, thermal control and communication functions for hallway lighting and automobile applications. According to the type and power of LED, a driver IC has already been developed and is produced. This driver IC makes the constant current and constant voltage available. However, if the LED driver allows delicate dimming control and thermal dissipation through allowance of LED off time, PWM control is needed. Therefore, a MCU (Microcontroller unit) for the PWM control as well as a driver IC for driving LEDs is needed. If this operation is embedded at this driver IC, the expense can be reduced. The LED controller integrated circuit (IC) was designed, simulated and fabricated in 0.35μm Magnachip/Hynix.

An Electrical Method for Junction Temperature Measurement of Power Semiconductor Switches- Baker, Nick -Aalborg Universy-DENMARK

An Electrical Method for Junction Temperature Measurement of Power Semiconductor Switches Baker, Nick Aalborg Universy-DENMARK 
 Dissertation submitted: April 6th 2016 PhD supervisor: Prof. Stig Munk-Nielsen Aalborg University, Denmark PhD
committee: Professor Josep Guerrero (chairman) Aalborg University Dr. Gernot J. Riedel ABB Cooperate Research Professor Philip Andrew Mawby University of Warwick PhD Series: Faculty of Engineering and Science, Aalborg University

Abstract
 Power semiconductor switches are critical components in power electronic converters and operate in thermally stressful environments. The junction temperature of a power semiconductor directly influences its power loss and is intrinsically linked to numerous failure mechanisms. Knowledge of this temperature is therefore important for optimal operation and for reliability reasons. If the junction temperature is known during the operation of a converter, real-time condition monitoring and active thermal control systems could be developed to improve system reliability. Performing direct measurements of junction temperature is difficult since the power semiconductor is generally encapsulated inside an array of packaging materials. Alternatively, the electrical behaviour of a semiconductor largely depends on temperature. If this relationship is known, the electrical parameters of the device can be monitored and used to estimate the junction temperature. These are known as Temperature Sensitive Electrical Parameters (TSEPs) and are one way to carry out non-invasive, real-time junction temperature measurements on fully packaged devices. Nevertheless, successful implementation of these techniques during the normal operation of a power semiconductor is thus far limited. Often holding back their use is the need to compensate for inherent fluctuations caused by a constantly changing electrical environment (or alternatively requiring interruption to normal operation to force fixed electrical conditions), and significant uncertainty over accuracy. As a result, this PhD aims to develop new methods, or improvements to existing methods, for junction temperature measurement via TSEPs during the operation of power semiconductor switches. In Chapter 1, the state-of-the-art in the topic of junction temperature measurement is introduced. A literature review of TSEPs investigated for use in operating power semiconductor switches is then provided. From this, several implementation issues are identified and used to formulate technical objectives for the PhD thesis. Chapter 2 introduces the first original contribution of the thesis. Two TSEP-based methods for junction temperature measurement, unpublished in scientific literature before the commencement of the PhD, are presented. The measurement principles are explained, and experimental validation is provided on Insulated-Gate-Bipolar-Transistors (IGBTs). The foremost advantages in the presented TSEPs are that they are measured without interruption to normal IGBT operation, and do not require compensation for varying load current conditions. The primary method presented is referred to as the Peak Gate Current (IGPeak) method, which is selected for further examination in Chapter 3. In Chapter 3, the second scientific contribution of the thesis is provided. Here, the accuracy of the IGPeak method on IGBTs is extensively examined using direct measurements of junction temperature from an Infra-Red camera. The validation is performed on IGBT dies with differing geometry, as well as IGBTs in both healthy and degraded conditions. Finally, IGBTs in a paralleled configuration are investigated. These results in terms of accuracy are compared with a traditional TSEP method commonly found in prior art.
LINK ORIGINAL
http://vbn.aau.dk/files/240989038/PHD_Nick_Baker_E_pdf.pdf

How to repair and service Off Grid Hydrid solar Inverter/UPS | Su-Kam 6.25KVA

MARCA SU-KAM Off Gr solar inverter is a highly efficient Inverter having the solar priority on the system. The inverter is designed to first charge through the panel and thereafter through grid if available. The low THD and low no load current in system helps optimizing its performance. Su-Kam’s three phase hybrid solar Inverter supplies pure power, which is actually purer than even the power supplied by the grid, and is 100% safe to run the most sophisticated, expensive and sensitive office equipment, silently. It has already established itself as a most reliable option to Generators at banks/ATM’s, hospitals, petrol pumps, shopping malls to name a few.
LINK
www.sukam-solar.com/

A Study on the Design and Evaluation of High Power Induction Lamp System -Young-il Chung

A Study on the Design and Evaluation of High Power Induction Lamp System
Young-il Chung
Dept. Information and Communication Engineering
Graduate school Wonkwang University
Abstract
Currently, road lightings are installed with less than 400W of existing metal halide lamps. These road lightings are being replaced by energy-saving lightings. Induction lamps are expected to be more actively replaced with targets for tunnel lighting and high ceiling lighting. Therefore, it is necessary to develop high efficiency, high power induction lamps system. In this study, the discharge tube design, lmap gas, lighting circuit, and lighting fixture were designed for the high power of the induction lamps. And Induction lamp system was optimized through electrical, optical, thermal characteristics analysis and simulation. For the development of the high power induction lamp, the induction lamp was fabricated according to the design factors such as gas type, gas pressure, discharge tube, ferrite core size, amalgam, and driving frequency after the improvement of the existing process.

In addition, the design and manufacture of the lighting circuit for the high power induction lamp were carried out. The light distribution characteristics through the optical design of the lighting fixture were compared and analyzed, and the illuminance distribution characteristics were simulated to develop the optimized high power induction lamp system. The discharge tube size of the high power induction lamp was 62mm, and the gas was optimized to Kr 100% and gas pressure 300 ~ 350[mmHg]. When the indium amalgam was applied, the induction lamp maintained the same power. As a result, optimization of the induction lamp, lighting circuit, and lighting fixture was completed in accordance with the rating. The characteristic analysis through the design of the lighting circuit for the induction lamp proceeded to improve and supplement. Based on the optical characteristics of the induction lamp and the system effect according to the driving frequency of the lighting circuit, the driving frequency was optimized to 135kHz. An optical simulation was performed according to the distance between the lamp and the reflector by using the OptisWorks program. and illuminance simulation was performed for each height according to the light distribution by using the Relux program. As a result, the high power induction lamp high ceiling fixture was completed.

In conclusion, Based on the high power induction lamp, ligthing circuit, lighting fixture optimization study was to present a guide for design and evaluation of induction lamp system. It is expected to be applied to additional induction lamp research and development in future.

SOLUCIONARIO DE MAQUINAS ELECTRICAS CHAPMAN 4 ed

LINK ORIGINAL
http://m4-fim.blogspot.com.br/2011/08/solucionario-de-maquinas-electricas.html

LINK DIRECTO
https://sites.google.com/site/mecanicafim/mecanica/ElectricMachinery4edChapman.rar?attredirects=0&d=1