Journal of Future Generation of Communication and Internet of Things
Volume:1 Issue: 1, sep 2021

Temperature, especially the hot spot temperature and top oil temperature, have played the most effective factor on the insulation life of the transformer. The prediction of top oil temperature and hot spot temperature is very important for estimating the loss of life of the transformer in the system. Therefore, an accurate technique is needed for solving the thermal models. This study determines an accurate hot spot temperature and then evaluates the loss of life of transformer according to the numerical analysis method. An alternative solution for solving the thermal model is proposed in this work. Results are compared with the actual temperature, which were measured by fiber optic sensors. The proposed technique is implemented on 250 electrical power transformer

A novel isolated zero-voltage-transition (ZVT) boost converter with coupled inductors is proposed in this paper to satisfy the high power, high step-up and isolated requirements. In the proposed converter, the input-parallel configuration is adopted to share the large input current and to reduce the conduction losses, while the output-series structure is employed to double the output voltage gain. Consequently, a transformer with a low turns ratio can be applied, which makes the transformer design and optimize easily. Moreover, the active clamp circuits are employed to reduce the switch voltage stress and to recycle the energy stored in the leakage inductance. The ZVT is achieved during the whole switching transition for all the active switches, so the switching losses can be reduced greatly. Furthermore, the diode reverse-recovery problem is partly solved due to the leakage inductance. In addition, the magnetic integration technology is applied to improve the efficiency and to reduce the magnetic component size. Finally, a 12-V input 96-V output 1-kW prototype operating with 100-kHz switching frequency is built and tested to demonstrate the effectiveness of the proposed converter.

In recent years, continuous and reliable electric energy supply is the objective of any power system operation. Over last decade FACTS devices have become popular and are very effective solution for many power system transmission problems. FACTS controllers can be used for steady state voltage regulation and control, steady state control of power flow on a transmission line transient stability enhancement, along with this it also reduces the problem of sub synchronous resonance. In this regard, Flexible Alternative Current Transmission Systems (FACTS) devices play a key role in enhancing controllability and increasing power transfer capability of the network. Thyristor Controlled Series Compensator (TCSC) is an emerging FACTS device designated to achieve this objective. The conventional methods in solving optimization problems in power systems suffer from several limitations due to necessities of derivative existence, providing suboptimal solutions, etc. Computational Intelligence plays an important role in determining the optimal solutions for multi – objective functions. A combinatorial analysis problem in power systems can be solved by modern heuristic methods in finding optimal solution. Thus, in this paper, Genetic Algorithm, a wing of evolutionary computation encapsulated with heuristic approach, is proposed in finding optimal location of TCSC.  IEEE standard 30bus system is considered to test the credibility of the proposed algorithm and the results thus obtained are subjected to analysis to determine the optimal location.

One of the most important things in designing modern telecommunication systems is the need to increase data transfer speeds. Increasing the transmission speed requires a wider bandwidth and work in a higher frequency range, and this has led to more attention to broadband circuits. For applications with a bit rate of 40 Gb/s, the bandwidth required for the amplifier is 28GHz. For this purpose, in this paper, 30GHz broadband amplifiers are designed. In this paper, 5 amplifiers with distributed cascade pseudo-differential topology with cascade classes of 2 to 6 stages in which there is only one gain cell in each floor are designed. The proposed circuits were implemented in RF_CMOS 0.18 µm technology and simulated in ADS software. The compromise of the parameters is in favor of the 4-stage amplifier. In this amplifier, the voltage gain in the 30GHz bandwidth is 25dB, while other scattering parameters are below 10dB. Power consumption is 162mW and chip area is 0.74mm2 and noise figure is 5dB, which are good results compared to other designs.

Model-based testing (MBT) has attracted a lot of attention and has been extensively applied in different areas such as probabilistic systems, mobile systems, concurrent systems, real-time systems, software product lines, etc. However, MBT approaches have some limitations and challenges that are mostly related to the incompleteness, high level of abstraction, complexity, and also the informal nature of input models. In the literature, there are different studies addressing these problems. In this paper, we represent a framework for model-based test case generation approaches according to the aforementioned challenges. In this regard, firstly, we categorize different coverage criteria used in MBT, and then show that MBT approaches have three main steps: preprocessing, test scenario generation, and concrete test case generation. Finally, for each step, we represent its necessity and classify the proposed methods