New China-Brazil earth resource satellite sent into space-CBERS-4A launch-PARCERIA BRASIL CHINA

CBERS-4A LAUNCH 

Etapa Final de Testes do Satélite Sino-Brasileiro - CBERS-4A
PROGRAMA BRASIL COM CIENCIA HISTORIA DE 30 ANOS DE PARCERIA BRASIL CHINA EM DESENVOLVIMENTO DE SATELITES
TAIYUAN, Dec. 20 (Xinhua) -- A new satellite, jointly developed by China and Brazil, was sent into space on Friday, pushing forward the aerospace cooperation between the two countries, according to the China National Space Administration (CNSA).

 The China-Brazil Earth Resource Satellite-4A (CBERS-4A) was launched on a Long March-4B carrier rocket at 11:22 a.m. Friday Beijing Time from the Taiyuan Satellite Launch Center in north China's Shanxi Province.

 The satellite is the sixth satellite under the earth resource satellite cooperation program between the two countries. It will obtain global optical remote-sensing data and support the Brazilian government's monitoring of the Amazon rainforest and the country's environmental changes.

 The CBERS-4A will replace CBERS-4, which was launched in 2014, to improve the resolution of the remote-sensing data, said CNSA. It is equipped with three optical payloads: a wide-range panchromatic multispectral camera developed by China, and a multispectral camera and a wide-field imager developed by Brazil. It has a better imaging capacity and higher positioning accuracy than CBERS-4, and can better meet the urgent needs of both countries in land and resources exploration, land classification, environmental protection monitoring, climate change research, disaster prevention and mitigation, crop classification and yield estimation, according to CNSA. It can also provide services for Asian, African and Latin American countries. In July 1988, China and Brazil signed the agreement establishing the joint research and production of the earth research satellites. The first such satellite was launched from China in 1999. Brazilian Minister of Science, Technology, Innovation and Communications Marcos Cesar Pontes said the cooperation between China and Brazil has contributed to international economic and social development. He said the new satellite will be used in fields such as earth resource monitoring, agriculture, meteorology, environmental protection, surveying and mapping, and serve Brazil and more developing countries.

Low Cost Drive Circuit and Control IC Design for AC-Direct LED Lamps-Doctoral Thesis Yoo-Chae Chung (정 유 채) Department of Electrical Engineering Pohang University of Science and Technology

Low Cost Drive Circuit and Control IC Design for AC-Direct LED Lamps-Doctoral Thesis Yoo-Chae Chung (정 유 채) Department of Electrical Engineering Pohang University of Science and Technology

 Abstract
This paper proposes a drive circuit for ac-direct LED lamps and its custom IC design. The proposed circuit consists only of a line filter, an LED bridge, a load inductor, a bi-directional switch, and a switch-control circuit. The switch connects the LED bridge to the power line directly. Each leg of the LED bridge consists of LEDs and a protection diode, all connected in series. The load inductor limits the bridge current. The switch operates at a zero current switching condition, so the circuit has high power efficiency PE. The circuit can operate at a free-volt input condition (85 < Vin,rms < 265 V). For all input voltage conditions the circuit had PE > 89%, luminous efficiency ~ 90 lm/W, power factor > 0.9 and 120 Hz flicker index ~ 0.3. The circuit satisfies the IEC 61000-3-2 Class C and the EN 55015 regulations. The proposed LED driver is wellsuited for use in household LED lamps.
LINK
https://www.mediafire.com/file/9g9cnq4x5nsm7ch/Low_Cost_Drive_Circuit_and_Control_IC_Design_for_AC-Direct_LED.pdf/file

Two-stage Active Gate Driver for SiC MOSFET by Abhay Negi Faculty of North Carolina State University Thesis Master of Science Electrical Engineering

Two-stage Active Gate Driver for SiC MOSFET by Abhay Negi 

A thesis submitted to the Graduate Faculty of North Carolina State University in partial fulfillment of the requirements for the degree of Master of Science Electrical Engineering
Raleigh, North Carolina 2017

ABSTRACT
NEGI, ABHAY. Two-stage Active Gate driver for SiC MOSFET. (Under the direction of Dr. Subhashish Bhattacharya).

Wide-band gap devices have rejuvenated the research in field of power electronics due to their superior properties over Silicon (Si) such as low on-resistance, high breakdown voltage, low switching losses and high temperature operation. However, SiC MOSFETs and GaN devices pose varied challenges due to high dv/dt and di/dt switching which creates issues related EMI, common mode current, high voltage overshoot, cross-talk, etc. In phase-leg configuration, due to high turn-on dv/dt of SiC MOSFET, a positive spurious voltage is induced on the gate to source voltage (Vgs) of the complementary MOSFET. This reduces signal to noise margin on the Vgs of the complementary MOSFET making it susceptible to spurious turn-on in the phase-leg. This can be reduced by using higher turn-on gate resistance for lower dv/dt but it will lead to higher switching loss. This thesis explores the twostage turn-on active gating for SiC MOSFETs to control turn-on dv/dt and di/dt independently. A two-stage active gate driver is designed which uses lower gate resistance in first stage to increase rate of current rise and higher gate resistance in second stage for lower turn-on dv/dt. A low-inductance DC bus PCB is designed to minimize voltage overshoots and ringing associated with high loop inductance. Switching losses are measured with and without active gating by double-pulse testing of 1200V/ 300A ROHM SiC half-bridge module BSM300D12P2E001 for comparison.

LINK:https://research.ece.ncsu.edu/bhattacharya/wp-content/uploads/2019/07/etd29.pdf

ENGENHEIRA TELECOMUNICAÇÕES GERALDIDE FRANCIA GANHADORA DO PROJETO PAPEATEC CONCURSO GENTE BRILHANTE TELEFONICA PERU

GERALDINE FRANCIA La tecnología es una herramienta que cambia vidas y Geraldine es prueba de ello. Esta ingeniera de telecomunicaciones promueve el aumento de la presencia femenina en este rubro porque sabe que traería grandes beneficios.

PROYECTO “Papeatec” – Yauyos, Lima El proyecto consiste en acercar la tecnología a estudiantes de una comunidad agrícola de Yauyos mediante talleres formativos en programación y electrónica aplicada a Internet. Los conocimientos adquiridos les servirán para desarrollar una red de sensores que miden las características de los suelos agrícolas y elegir el más adecuado para cada tipo de sembrío. Los conocimientos a brindar favorecerán a que los estudiantes descubran cómo la tecnología puede mejorar sus vidas, a través de diversos ejemplos de tecnología aplicada a agricultura, ganadería y acuicultura.

FUENTE ORIGINAL:
https://elcomercio.pe/especial/comprometidosconlaeducacion/temporada-2/geraldine-francia-noticia-1994800?utm_source=ElComercio&utm_medium=Portada-Principal&utm_campaign=fundacion-telefonica

A Non-isolated ZVZCS Resonant PWM DC-DC Converter for High Step-up and High Power Applications Author Jung,Byoung Kil Dept.of Control and Instrumentation Eng. Graduate School of Industry and Engineering Seoul National University of Science and Technology

Abstract
 A Non-isolated ZVZCS Resonant PWM DC-DC Converter for High Step-up and High Power Applications Jung,ByoungKil (SupervisorChoi,SeWan) Dept.of Control and Instrumentation Eng. Graduate School of Industry and Engineering Seoul National University of Science and Technology

 The demand of non-isolated high step-up DC-DC converters is gradually increasing in many applications such as dc back-up energy systems for UPS, photovoltaic and fuel cell systems and hybrid electric vehicles.This paper proposes non-isolated step-up DC-DC converters with an improved switching method.The proposed converter shows ZVS turn-on of the switches in CCM as well as reduced turn-off switching losses owing to the switching method that utilizes Lr-Cr resonance in the auxiliary circuit.Also,owing to the proposed switching method the switching losses associated with diode reverse recovery become negligible even in the small dutycycle.The capacitance in the auxiliary circuit is significantly reduced compared to PWM method.The duty cycle loss is further reduced resulting in increased step-up ratio. Experimental results from a 2kW prototype of two-phase interleaved version are also provided to validate the proposed concept.

 LINK FULL TEXT:https://www.mediafire.com/file/47c75j6rsx645de/A_Non-isolated_ZVZCS_Resonant_PWM_DC-DC_Converter.pdf/file