• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.3
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• pp.104-111
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• 2018

The sensorless control of high efficiency air compressors using a permanent magnet type synchronous motor as an oil-free air compressor is quite common. However, due to the nature of the air compressor, it is difficult to install a position sensor. In order to control the permanent magnet type synchronous motor at variable speed, the inclusion of a position sensor to grasp the position of the rotor is essential. Therefore, in order to achieve sensorless control, it is essential to use a permanent magnet type synchronous motor in the compressor. The position estimation method based on the back electromotive force, which is widely used as the sensorless control method, has a limitation in that position errors occur due either to the phase delay caused by the use of a stationary coordinate system or to the estimated back electromotive force in the transient state caused by the use of a synchronous coordinate system. Therefore, in this paper, we propose a method of estimating the position and velocity using a rotation angle tracking observer and reducing the speed ripple through a disturbance observer. An experimental apparatus was constructed using Freescale's MPU and the feasibility of the proposed algorithm was examined. It was confirmed that even if a position error occurs at a certain point in time, the position correction value converges to the actual vector position when the position error value is found.

• The Journal of the Korea institute of electronic communication sciences
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• v.13 no.3
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• pp.609-616
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• 2018

The purpose of this study is to describe the technologies necessary to design responsive web with the use of the responsive website based on implementation structure as a prototype. Responsive design means the process of analyzing prototype requirements on the basis of implementation and applying the analysis results to development. The design method based on the principle of priority in development was established, and then flexibility and variability through design formula were set up. After that, the user-oriented primary principle and secondary principle were drawn to establish implementation structure. In the way of discussing compression technologies, a method of combination was searched for, and then a method of asynchronous script scalability in line with a web prototype was found. Today, a website or a web application needs to be adopted and accessed regardless of device types. As a solution, a responsive website design method was found. Important technologies for the implementation structure for the responsive website design method and its relevant prototype website were came up with.