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Due to aging and wear of the electrical equipment existing in power system and also due to the fast technological change is necessary to take timely and appropriate decisions (maintenance, repair, relocation, refurbishment, replacement) for moral or/and physically damaged components and adding supplementary elements (features), including the introduction of new technologies. This paper presents the...
Wind pumped storage systems are becoming more and more attractive in the context of higher quantities of wind power to be absorbed by the grid, power system stability, load balancing and frequency control. The power losses of a pump drive inverter system are evaluated considering two different topologies: 2L VSC and respectively 3L NPC VSC starting from 2.2 kW up to 1.85 MW power levels. The analyze...
This paper develops a scalar V/f control system for permanent magnet synchronous motor (PMSM) drives with two stabilizing feedback corrections: i) a voltage-vector speed correction using active power variation, in action only in transient states, and ii) a voltage amplitude correction based on unity power-factor regulation loop, employing reactive power. Motor / generator operating mode is allowed...
The present paper gives a new neural network based adaptive control for the induction motor using input-output feedback linearization control. A simple multilayer neural network is used for the estimation of rotor and stator time constant inverses as well as the load torque. The suggested estimator is a model reference adaptive control based which uses the measured and estimated motor states such...
Wind turbines represent elastically coupled multi-mass systems. Dynamic load changes caused by a gust of wind lead to peaks in the shaft torsion torque and result into high stress for the system. This paper presents an opportunity to integrate a stress minimizing control strategy, which was presented in [7], on wind turbines with doubly fed induction generator (DFIG). To avoid extensive measurements...
Hybrid electric vehicles and full electric vehicles are becoming a viable alternative to gasoline or diesel powered vehicles. Four main factors are contributing to this evolution: oil price, pollution, greenhouse effect and advances in electrochemical energy storage. All major car manufacturers are developing projects in this area. Until now, the full electric vehicles available on the market have...
A visual servoing application for automated object detection is described. This application is based on a computer vision algorithm that enables: the detection of colored objects, which are located on a conveyor pallet, the height calculation of these objects, the determination of their type, their position and orientation, in order for a SCARA robot to be able to manipulate them. The object detection...
The interest in the development towards intelligent microgrids which use renewable energy as primary sources has significantly increased in the last two years. The present paper examines and proposes a new digital control solution for bidirectional DC-DC converters. In order to control the converter in both directions the novel algorithm uses the current that charges and discharges the storage devices...
The present article discusses an experimental model of the fractal logarithmic segment antenna. Theoretical aspects, such as design principles and basic equations, as well as experimental results are presented. The main experimentally obtained parameters are: microwave frequency bands for emission/transmission and reception, directivity, VSWR (Voltage Standing Wave Ratio)[1].
An inductive sensor (Rogowski coil) — based digital measuring system able to operate in any frequency range both in steady state and in transient duty, which uses a self-developed numerical integration system, is presented in this paper. Besides, the measuring system has an extended input signal range achieved by using a nonlinear input attenuator. Software validation is done by using the analytical...
The flow electrification of mineral oil produces local electric discharges which may facilitate the damage and worsen the physico-chemical properties of the electrical power transformer insulation systems. This paper presents a study concerning the influence of the mineral oil ageing condition on the flow electrification phenomenon. The flow electrification current has been measured with a spinning...
Permanent magnet linear synchronous motors (PMLSMs) are becoming increasingly popular for implementation in industrial precision stages. While PMLSMs minimize friction and other undesirable effects in the stages, they induce thrust ripple, which significantly affects control of the devices and has recently been the subject of concentrated research. This paper presents the design and implementation...
Today's desired power managing devices are smart, embeddable, highly energy efficient and with small form factor. The main goal of each design is to find the optimal combination between performance and costs. The performance can be raised with optimized control algorithms implemented on a powerful MCU platform capable of performing even multiple tasks in parallel. A good shaped charging and balancing...
This paper describes the students' awareness regarding the methods employed to mitigate the negative impact of computers on the environment. Several topics considered important by the students were analyzed — transforming computers into recyclable waste, increasing users' awareness toward extending computer lifetime, encouraging the reuse of old and obsolete computers, employing new ecological materials...
The simulation and the analysis of a power distribution network (PDN), termed power integrity (PI), are performed in the frequency domain and primarily involve analyzing the power and ground planes and the decoupling capacitors. The capacitors provide a temporary source of localized energy for instantaneous current demands from a IC, and a low-impedance return path for high frequency noise. Capacitors...
The paper proposes an improved evaluation method for the calculation of the electric efficiency and power factor of the crucible induction furnaces. The method's advantage is the use of calculation expressions with per unit variables, without any direct dependence on the geometrical dimensions, which allow a quicker estimation of the energetic parameters based on the furnace capacity and physical...
The paper intends to re-design a permanent magnets synchronous generator (PMSG) having low efficiency, in order to bring it in the range of actual generators. The starting point was a real machine which was transformed from induction machine into permanent magnets machine for series production. It had low efficiency and low power factor. By following the operational aspects of the machine and the...
The paper deals with modified PI current control structures for large AC drive systems which use surface mounted permanent magnet synchronous machines or squirrel-cage induction motors supplied with voltage source inverters. In order to reduce the power losses caused by high frequency switching of the semiconductor devices, various compensation methods are used and a modified structure for a PI current...
The radiation patterns obtained for planar array antennas with different number of elements along x-axis and y-axis are presented. The opening angle of the main lobe is used to compare the results obtained in these situations. Using Matlab, we calculated the radiation patterns for a planar array antenna, obtained in E — plane, H — plane and respectively 3D representation. The results are presented...
In this paper a method to eliminate the estimation of Direction-of-Arrival (DoA) for an interfering signal is investigated. In order to estimate the DoA, the Multiple Signal Classification (MUSIC) algorithm was used. All the simulations are implemented in Matlab, for different number of elements.
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