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"The dual-inverter fed open-end winding configuration can be categorized as a new breed of multi-level converters. The structure is simple and offers a lot of advantages. However, the development of suitable PWM schemes is more complicated, due to the availability of a large number of switching states and existence of the multiple two-dimensional planes. An overview of attempts to develop suitable modulation techniques for the dual-inverter fed five-phase machine drives recognizes that progress has been made over the past few years. This paper presents a performance comparison of three PWM schemes of the dual-inverter fed five-phase, open-end winding motor drives. The quality of the phase output voltages are compared and the adequate analyses are provided. The simulation results show that the Carrier Based Phase Disposition (PD) PWM scheme enables generation of the most excellent output voltage among the three PWM schemes. The Total Harmonics Distortion (THD) of the output voltages generated by the carrier based PWM scheme reduces by 65% and 15% on average compared to the THD of the output voltages produced by the URS PWM scheme and the decomposition PWM scheme respectively."

"Beberapa studi eksperimental dan teoretis baru-baru ini mengungkapkan bahwa material dua dimensi (2D) merupakan kandidat yang menjanjikan untuk teknologi informasi berbasis seleksi derajat kebebasan elektron, spin, hingga valley, bergantung pada interaksinya dengan cahaya. Dalam hal ini, ada banyak material 2D yang perlu ditelusuri sifat elektronik dan sifat optiknya untuk mendapatkan polarisasi sifat fisis tertentu, terutama polarisasi valley yang terkait dengan seleksi derajat kebebasan keadaan elektron pada titik tertentu di ruang momentum. Melalui perhitungan first principles untuk monolayer α-Sb dan NbS2, kami memverifikasi kondisi material 2D yang dapat memiliki potensi untuk aplikasi valleytronics melalui polarisasi optik dari valley-nya. Penyerapan cahaya terpolarisasi melingkar oleh material dihitung melalui pendekatan dipol dengan menggunakan vektor dipol dan matriks elemen transisi optik. Kami menemukan bahwa elektron di valley yang berbeda pada zona Brillouin yang memenuhi simetri pembalikan waktu untuk monolayer α-Sb dan NbS2 dapat tereksitasi secara selektif oleh cahaya terpolarisasi melingkar kiri atau kanan. Khusus NbS2, intensitas maksimum polarisasi valley mencapai 100% di valley K atau K’ tergantung polarisasi cahaya melingkar (kanan atau kiri) yang diberikan. Selektivitas yang sangat baik ini diduga terkait erat dengan struktur kristal heksagon tertekuk (buckled) dengan ikatan polar yang dimiliki oleh NbS2 alih-alih struktur berkerut (puckered) dengan ikatan nonpolar dari α-Sb.

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Recent experimental and theoretical studies revealed that two-dimensional (2D) materials are a promising candidate for information technology based on selectivity of electron, spin, and valley degrees of freedom under interaction with light. In this case, there are a lot of 2D materials whose electronic and optical properties need to be investigated so that we can obtain polarization of certain physical properties, especially valley polarization which is related to the selection rule of electronic excitation by light at a certain point (the so-called valley) in momentum space. By using first-principles calculations for monolayer α-Sb and NbS2, we verify some conditions for 2D materials that are potential for valleytronics applications utilizing the optical valley polarization. In this case, we need to calculate the absorption of circularly polarized light by the materials through the dipole approximation which gives the dipole vectors and optical transition matrix elements as the main quantities to be investigated. We found that electrons at the different valleys, which satisfy time-reversal symmetry, in the Brillouin zone of monolayer α-Sb and NbS2, can be selectively excited by left-handed or right-handed circularly polarized light. Specifically for NbS2, the maximum intensity of valley polarization can reach 100\% at the K or K’ valley depending on the given (left-handed or right-handed) circular polarization of light. We expect that such an excellent selectivity in NbS2 is closely related to its buckled hexagonal lattice and polar bonding, in contrast to the puckered lattice and nonpolar bonding in α-Sb. "