Internal degradation of 980nm emitting single-spatial-mode lasers during ultrahigh power operation

2014 ◽  
Author(s):  
Jens W. Tomm ◽  
Martin Hempel ◽  
Thomas Elsaesser ◽  
Juan Jimenez ◽  
Vanesa Hortelano ◽  
...  
Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4707
Author(s):  
Ching-Hua Chen ◽  
Jia-Jun Zhang ◽  
Chang-Han Wang ◽  
Yu-Chia Chang ◽  
Pinghui S. Yeh

Constant light power operation of an ultraviolet (UV) LED based on portable low-cost instrumentation and a monolithically integrated monitoring photodiode (MPD) has been reported for the first time. UV light irradiation has become one of the essential measures for disinfection and sterilization. Monitoring and maintaining a specified light power level is important to meet the criteria of sterilization. We built a module composed of a monolithically integrated UV LED and MPD, a transimpedance amplifier, an Arduino Uno card, a digital-to-analog converter and a Bluetooth transceiver. An Android App that we wrote remotely controlled the UV LED module via Bluetooth. The Arduino Uno card was programmed to receive demands from the smartphone, sent a driving voltage to the LED and returned the present MPD voltage to the smartphone. A feedback loop was used to adjust the LED voltage for maintaining a constant light output. We successfully demonstrated the functioning of remote control of the App, and the resultant UV LED measured power remained the same as the setting power. This setup can also be applied to visible or white LEDs for controlling/maintaining mixed light’s chromaticity coordinates or color temperature. With such controlling and internet capability, custom profiling and maintenance of precision lighting remotely would be possible.


2021 ◽  
pp. 1-11
Author(s):  
Zhengxia He ◽  
Yanqing Zhou ◽  
Xin Chen ◽  
Jianming Wang ◽  
Wenxing Shen ◽  
...  

2021 ◽  
pp. 2000103
Author(s):  
Narayan Bhusal ◽  
Sanjaya Lohani ◽  
Chenglong You ◽  
Mingyuan Hong ◽  
Joshua Fabre ◽  
...  

2021 ◽  
Author(s):  
Shuanglu Zhang ◽  
Atsushi Okamoto ◽  
Taijun Shiba ◽  
Hotaka Hayashi ◽  
Kazuhisa Ogawa ◽  
...  

Author(s):  
Mostafa Ahmed ◽  
Ibrahim Harbi ◽  
Ralph Kennel ◽  
Mohamed Abdelrahem

AbstractPhotovoltaic (PV) power systems are integrated with high penetration levels into the grid. This in turn encourages several modifications for grid codes to sustain grid stability and resilience. Recently, constant power management and regulation is a very common approach, which is used to limit the PV power production. Thus, this article proposes dual-mode power generation algorithm for grid-connected PV systems. The developed system considers the two-stage PV configuration for implementation, where the dual-mode power generation technique is executed within the DC–DC conversion (boost) stage. Most of the techniques adopted for dual-mode power operation employ the conventional perturb and observe method, which is known with unsatisfactory performance at fast-changing atmospheric conditions. Considering this issue, this study suggests a modified maximum power point tracker for power extraction. Furthermore, a new adaptive DC-link controller is developed to improve the DC-link voltage profile at different operating conditions. The adaptive DC-link controller is compared with the traditional PI controller for voltage regulation. The inverter control is accomplished using finite-set model predictive control with two control objectives, namely reference current tracking and switching frequency minimization. The overall control methodology is evaluated at different atmospheric and operating conditions using MATLAB/Simulink software.


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