Journal of Majlesi Journal of Mechatronic Systems
Volume:9 Issue: 3, Sep 2020

In this paper mechanical behavior of hydro-electric turbine is investigated during load rejection test. For this purpose, several load rejection tests have been executed on unit 5 and 6 of Masjed-soleiman hydropower plant with different load before any load rejection. Then for any individual test important parameters have been measured. Finally based on numerical methods empirical formulations have been developed.

This paper proposes the mitigation of grid voltagedisturbances using a Flying-Capacitor Modular Multilevel Inverter(FC-MMI) based DynamicVoltage Restorer (DVR) solution.Which regulates the injection of thecompensation voltage in series and synchronism with the gridduring the voltage disturbance events, the auxiliary capacitorvoltage, while controlling the FC-MMIoutput current. this paper presents a flying-capacitor modularmultilevel converter (FC-MMI) based on series-connectedsub-modules. The proposed FC-MMIcircuit is characterized by thecross connection of upper and lower arm middle taps through aflying capacitor in per phase leg. By properly controlling the ACcurrent flowing through the flying capacitor, the power balancebetween upper and lower arms is achieved, leading to very smallvoltage ripples on sub-module DC capacitors.thatthe proposed FC-MMIalong with the proposed controlmethod performs satisfactorily in dynamic and static state.This feature enables the structure to be used to compensate for the power quality of power distribution networks. Modified Phase Modified Pulse Width Modulation (MPSPWM)in the inverter is used to create the desired waveform. TheIn-Phase control method is selected to control the proposed DVR and use the synchronous reference frame (SRF) method to detect the network voltage fluctuations. To verify and validate the proposed DVR performance, simulations are carried out in the MATLAB / SIMULINK software environment, and the results indicate the optimal performance and desirability of the proposed DVR to compensate for the voltage sag, swell and flicker power distribution grids. Theoretical analysis and simulation results are given toshow the high performance of the proposed solution

Radar systems are the country's first surveillance system against any foreign invaders entering the country's airspace or maritime zone, in other words, they are at the forefront of countering foreign threats.Any entry into the skies or seas of any country, whether for reconnaissance or offensive operations, requires that the radar not be detected in the presence of an attacker or deceived if it is detected.So far, many methods have been proposed, such as single pulse, cone reversal, including ground reflection, reverse polarization to deceive radar systems.In this article, we try to deal with the method of deception in the radar angle with the cross-eye method. This method has a special ability to deceive the radar systems of the other side.By receiving the information of the signal received from the radar and processing it, it is able to give the radar to another direction that has no purpose in that areaby giving fake coordinates to radar.In this method, which is created by combining the disruption signal with the main target signal, a distorted wave plate is created at the radar location. The presence of this distorted wave plate causes the radar antenna to be misdiagnosed at the target angle

In this paper efficient hardware implementation of Kohonen Neural Network (KNN) has been discussed. To achieve this, current mode has been chosen as the basis of circuit level implementations. By considering this, a novel low power current squarer circuit is introduced which has successfully been employed in the body of the network. Also, the evaluative operations have been carried out using current comparators. Moreover, careful design considerations are utilized to optimize the performance of the proposed architecture. In summary, the main building blocks of proposed architectures are Euclidean Distance Calculation circuit (EDC), Winner Takes All (WTA) circuit and Adaptive Weight Change (AWC) mechanism. The designed process has been done in analog domain to achieve more precision. As a consequence, the notable advantage of this network is its low power consumption and chip area compared to similar digital networks. Consisting of four output neurons each of which has three weights, the circuit is implemented in CMOS 0.18µm process and occupies a chip area equal to0.04 and consumes 0.5mw of power for 1.8V supply. System level and circuit level simulation results have been provided to show the correct behavior of implemented network where the conformity between the results is in the moderate level.

The mechanical vibration of BLDC Motors during the rotation of the rotor due to torque ripple and radial forces, makes them difficult to use. Thus, in this paper, the factors affecting this problem, such as the combination of the number of poles and slots, shape of the magnet and magnetization method, slot opening in the stator laminations, geometric symmetry of the rotor and air-gap are analyzed for three different structures (integer-slot with symmetric air-gap, fractional-slot with symmetric air-gap and fractional-slot with asymmetric air-gap) of BLDC Motors using finite-element (FE) analysis. Based on the analysis results, the fractional-slot motor with symmetric winding is chosen as a suitable structure with minimum mechanical vibration level. Finally, in order to reduce the cogging torque, the Proposed Firefly Algorithm is used to optimize the pole arc and slot opening.

The main objective of this work is to present the control and observation laws and their application on the asynchronous machine, and a comparative study of the performance of a vector control by conventional regulators and of a control with observer. This work will be devoted to the implementation of a state observer to improve the stability of the vector control of the asynchronous machine in the event that one of its internal parameters (such as stator resistance) varies. Simulation results will be redone to be able to judge the contribution of this observer to the performance and robustness of the control.