Modeling and controlling of doubly fed induction generator (DFIG) are presented in this paper. The DFIG is considered in the positive synchronous reference framework under distorted grid voltage situations (DGVS). The DFIG electromagnetic torque, active and reactive powers of the instantaneous stator are discussed under the condition of harmonically DGVS. Methods: Four alternative control strategies are implemented on DFIG system to enhance the responses under DGVS.
This paper introduces a millimeter-wave multipleinput-multiple-output (MIMO) antenna for autonomous (selfdriving) cars. The antenna is a modified four-port balanced antipodal Vivaldi which produces four directional beams and provides pattern diversity to cover 90 deg angle of view. By using four antennas of this kind on four corners of the car’s bumper, it is possible to have a full 360 deg view around the car.
A dual-polarized dual-layer wideband microstrip antenna is presented. Dual orthogonal linear polarization and enhanced isolation between two ports are achieved by employing two radiating patches perpendicular to each other and printed on two separate substrates. Broadband behavior of the antenna is realized by using two wideband double-sided printed strip dipole and angular ring as radiating patches along with wideband baluns as feeding system. The patches are connected to baluns with two separate twin-lead transmission lines.
Due to ever–increasing demands for optical fibers with low–latency used in IoT optical fiber networks, in this theoretical study, a non–zero dispersion shifted fiber (NZDSF) with a particular refractive index which had a minimum latency at 1352 nm is designed. In comparison to a commercial NZDSF, the latency has improved by 0.002ìs in the designed NZDSF with an effective area of 102 and macro bending loss of 517.3 /110−×dBkm. The dispersion of this fiber is found to be 1.10625ps/nm.km which is comparable to the commercial NZDSF fiber.
data at a maximum level. In order to achieve this technology, fibers with the lowest bending and splice losses are required. In this paper, the losses of bending and splice joints in single mode optical fibers have been reviewed with a variety of designs, including holey fibers, nanoscale optical fibers, and microstructured optical fibers. By comparing the losses of these fibers, we chose the best fiber with the lowest losses in designing FTTH that is used for two purposes of reducing costs and improving optical network performances.
In new generation of optical communication networks, simultaneous transmission of several information channels has become possible over a single optical fiber. But dispersion and dispersion slope of optical fibers are important factors, which limit high capacity optical fiber communication systems to perform high speed transmission.
پژوهشگاه ارتباطات و فناوری اطلاعات (مرکز تحقیقات مخابرات) ایران، یکی از قدیمیترین نهادهای پژوهشی حاکمیتی در حوزه فاوا و مغز متفکر و مشاور مادر وزارت ارتباطات و فناوری اطلاعات به شمار میرود. از ماموریتهای اصلی این پژوهشگاه نهادینه کردن رشد و ارتقای وضعیت دانش، فناوری و نوآوری کشور با بسترسازی و برنامهریزی خردمندانه همراستا با اولویتهای تعیین شده در اساسنامه، احکام و اسناد بالادستی کشور میباشد.