scholarly journals Thermal Design, Analysis and Packaging of an Airborne Multi-output Power Supply Unit

2018 ◽  
Vol 68 (3) ◽  
pp. 235
Author(s):  
Sogunuru Annapurna ◽  
Pradapan Vikram ◽  
Suma Varughese

Design of airborne multi-output power supply unit (MOPS) is restricted by space, weight and predefined geometry of air flow path. The unit is cooled by ram air and hence, exposed to the extreme external thermal environment that changes typically from +55°C to -40°C, from ground to cruising altitude within a few minutes. Hence the design should meet the thermal requirements of the electronics inside the packaging adequately, for both the positive and negative extremities of the temperature, so that device limiting temperatures are not exceeded. At the same time, it must accommodate the necessary circuitry. Details of the thermal and mechanical design and performance of the MOPS unit at various altitudes, hot spot location, flow requirements and optimal heat sink design are presented in this paper.

Author(s):  
M Ishizuka

This paper describes a practical thermal design approach to natural air-cooled electronic equipment casings. A set of simplified equations for the thermal design of natural air-cooled electronic equipment casings has been proposed. The proposed set of equations satisfied the demand of practical air-cooling systems, since it takes account of factors such as the stack effect, the air flow resistance and the heat transfer due to natural convection. The effects of the outlet area and the location of the main power supply unit on the natural cooling capability of electronic equipment casings were studied using a set of equations. The results have shown that a uniform temperature distribution could be achieved when the main power supply unit was placed at the bottom of the casing. It has also been suggested that the value of the heat removed from the casing surface could be more significant than that from the outlet vent in the thermal design of natural air-cooled electronic equipment casings.


2020 ◽  
Vol 96 (3s) ◽  
pp. 321-324
Author(s):  
Е.В. Ерофеев ◽  
Д.А. Шишкин ◽  
В.В. Курикалов ◽  
А.В. Когай ◽  
И.В. Федин

В данной работе представлены результаты разработки СВЧ монолитной интегральной схемы шестиразрядного фазовращателя и усилителя мощности диапазона частот 26-30 ГГц. СКО ошибки по фазе и амплитуде фазовращателя составили 1,2 град. и 0,13 дБ соответственно. Максимальная выходная мощность и КПД по добавленной мощности усилителя в точке сжатия Ку на 1 дБ составили 30 дБм и 20 % соответственно. This paper describes the design, layout, and performance of 6-bit phase shifter and power amplifier monolithic microwave integrated circuit (MMIC), 26-30 GHz band. Phase shifter MMIC has RMS phase error of 1.2 deg. And RMD amplitude error is 0.13 dB. MMIC power amplifier has output power capability of 30 dBm at 1 dB gain compression (P-1dB) and PAE of 20 %.


2021 ◽  
Vol 11 (13) ◽  
pp. 5865
Author(s):  
Muhammad Ahsan Gull ◽  
Mikkel Thoegersen ◽  
Stefan Hein Bengtson ◽  
Mostafa Mohammadi ◽  
Lotte N. S. Andreasen Struijk ◽  
...  

Wheelchair mounted upper limb exoskeletons offer an alternative way to support disabled individuals in their activities of daily living (ADL). Key challenges in exoskeleton technology include innovative mechanical design and implementation of a control method that can assure a safe and comfortable interaction between the human upper limb and exoskeleton. In this article, we present a mechanical design of a four degrees of freedom (DOF) wheelchair mounted upper limb exoskeleton. The design takes advantage of non-backdrivable mechanism that can hold the output position without energy consumption and provide assistance to the completely paralyzed users. Moreover, a PD-based trajectory tracking control is implemented to enhance the performance of human exoskeleton system for two different tasks. Preliminary results are provided to show the effectiveness and reliability of using the proposed design for physically disabled people.


Aerospace ◽  
2021 ◽  
Vol 8 (6) ◽  
pp. 150
Author(s):  
Yeon-Kyu Park ◽  
Geuk-Nam Kim ◽  
Sang-Young Park

The CANYVAL-C (CubeSat Astronomy by NASA and Yonsei using a virtual telescope alignment for coronagraph) is a space science demonstration mission that involves taking several images of the solar corona with two CubeSats—1U CubeSat (Timon) and 2U CubeSat (Pumbaa)—in formation flying. In this study, we developed and evaluated structural and thermal designs of the CubeSats Timon and Pumbaa through finite element analyses, considering the nonlinearity effects of the nylon wire of the deployable solar panels installed in Pumbaa. On-orbit thermal analyses were performed with an accurate analytical model for a visible camera on Timon and a micro propulsion system on Pumbaa, which has a narrow operating temperature range. Finally, the analytical models were correlated for enhancing the reliability of the numerical analysis. The test results indicated that the CubeSats are structurally safe with respect to the launch environment and can activate each component under the space thermal environment. The natural frequency of the nylon wire for the deployable solar panels was found to increase significantly as the wire was tightened strongly. The conditions of the thermal vacuum and cycling testing were implemented in the thermal analytical model, which reduced the differences between the analysis and testing.


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