Journal of Majlesi Journal of Mechatronic Systems
Volume:9 Issue: 2, Jun 2020

The cause of harmonics is the presence of nonlinear elements in the power system. Examination of harmonic issues led to research on the quality of electricity. Harmonic distortions are still the most important issue in electricity quality. Fortunately, not all power systems have a harmonic problem, and only a small percentage of feeders in electrical systems are affected by harmonic factors. In this paper, a three-wire thyristor-based rectifier load with a three-wire transformer structure is used to power the power supply while an active filter shunt to the instantaneous power theory control strategy is proposed to eliminate the harmonics generated by the rectifier loads. Also, the proposed design was simulated in MATLAB/SIMULINK software environment and finally, in order to prove its efficiency and effectiveness, it was compared with two important strategies of control conductive filter and conductive power filter. The simulation results show that the proposed strategy has less harmonic distortion of the entire network flow compared to the two methods, conductive power filter and controlled conductive power filter. According to the instantaneous power theory, first the active and reactive power of the harmonic power is calculated, the according to these values, the compensating currents proportional to this power are produced by the governing relations in d-q coordinates and injected into the network in shunt. Harmonic compensation currents in terms of size and phase are such that when they are collected by the load current, they eliminate the harmonic components of the current flowing to the network.

This paper presents the model reference adaptive control (MRAC), a combination of a Gough-Stewart platform with an adaptive control strategy for force control. For this purpose, firstly, the platform geometry is described followed by solving the inverse kinematic equations using the so-called vector method. Afterward, the dynamic robot model is built utilizing the MSC Adams software, with its linear form generated by the control plugin of the software, where the model takes the force as input and returns the displacement as output. As a next step, an adaptive control strategy is formulated to control the position of the robot operator and then simulated in MATLAB software. The control strategy has two components, namely the feedback and feedforward control strategies. The adaptive law is calculated based on the Lyapunov theory. Finally, the controller parameters are optimized through a genetic algorithm based on integral time squared error (ITSE) to minimize the system error over time. The results proved that the proposed system outputs are in agreement with the corresponding values for the model reference and that the controller performs well in presence of usual levels of noise and/or disturbance.

Direct torque control (DTC) of the induction motor (IM) is important in many applications. This paper presents improved five-level DTC using intelligence techniques. Two control approaches using neural networks DTC and fuzzy logic DTC are proposed and compared. The validity of the proposed controls scheme is verified by simulation tests of an induction motor. The stator current, stator flux and torque are determined and compared to the above techniques. The fuzzy DTC proposed control is shown to be able to reduce the torque and stator flux ripples and to improve performance DTC.

In this paper, a hexagonal solid state photonic crystal fiber at 10 terahertz is presented. First, by finding the main conductive fashion and its dispersion, the dispersion variation evaluation is based on the constant changes of the fiber network in the main mode with the aim of achieving the least dispersion. In the next section, dispersion changes are measured and evaluated based on changes in the radius size of the cavities of the photonic crystal fiber area. Then the fiber-forming holes have become elliptical geometry, and the size of the disintegration has been discussed for this change. Finally, by changing the refractive index of the fiber region, the size of the disintegration has been investigated. The optimized structure is obtained for the geometries of all the steps that have the least disintegration. In this way, the proposed structure has a dispersion of -75×10-3 picosecond per nanometer per kilometer, which is a good fit for similar designs.

The current competitive arena has required Agile software companies to adopt the proper solutions in order to improve productivity like other companies, but focusing on the governing Agile principles and values has led to the dominance of tacit/implicit knowledge over explicit one in the development teams. Tacit knowledge is accompanied by uncertainty, which is among the most important factors affecting productivity. In such a situation, the adoption of a modern managerial approach is essential in order to stabilize the existing tacit knowledge. Therefore, the current research proposed a combined framework of knowledge management based on Scrum development cycle adaptation to Mark knowledge management as a model that has the potential to manage tacit knowledge. Employing the proposed framework in a case study revealed significant results in practice. The results indicated an increase in the total average of productivity by 3%, and a reduction in the number of change requests by 3, and a reduction in the number of rework tasks by 8 in the team understudy.

In this paper, a new hybrid unified power quality conditioner (HUPQC) is proposed to improve current and voltage imperfections in distribution systems. The proposed HUPQC is comprised of the shunt hybrid active power filter (SHAPF), the dynamic voltage restorer (DVR) and the isolated bi-directional DC-DC converter. The main contribution of the study is a new HUPQC topology that enables the reduction in the voltage rating of the DC link capacitor by the help of the SHAPF. The cost and size of the DC link are reduced and switching losses of the voltage source inverter (VSI) is reduced with the low voltage DC link advantage of SHAPF. The DC-DC converter provides isolation and bi-directional power flow between the DVR and the SHAPF during voltage sag and swell. The performance of the proposed HUPQC is evaluated through extensive simulations for mitigating voltage sag/swell and compensating current harmonics by using MATLAB/SIMULINK simulation tool.