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The use permanent magnet synchronous generators (PMSG) in wind turbines has been increase considerably in offshore applications due to its efficiency, low maintenance costs and reliability. PMSG's are connected to the grid by means of frequency converters. Generally a back-to-back full converter structure is preferred. This work presents the application of interconnection and damping assignment passivity-based...
This paper presents a model of typical three-phase, three-wire and two-level PWM controlled voltage-source converters (VSC) suitable to investigate the non-characteristic harmonic generation at dc- and ac-side of the converter under sinusoidal unbalanced voltage condition, e.g., third order current harmonic component of positive-sequence in the VSC ac-side current. The proposed model, based on instantaneous...
Three-phase inverter has been widely applied in various applications, and lots of control schemes are investigated for the inverter powering nonlinear load, aiming to achieve favorable performance. However, the model currently proposed for inverter is based on linear load, which is not suitable for condition with nonlinear load. In this paper, a novel modeling method for three-phase inverter powering...
Under certain conditions Electro-Mechanical Actuators are able to regenerate, rather than consume electrical power. Within the More Electric Aircraft this possibility must be carefully considered in order to ensure safe and stable operation of the electrical systems. This paper assesses various strategies for the management of regenerated power in the More Electric Aircraft. A range of options are...
This paper introduces the control algorithm designed for the three-phase voltage-source active rectifier multilevel converter. The presented control strategy allows direct current control separately for each phase, that's important during non-symmetrical converter load. The control provides voltage balancing on individual power cells directly at the control structure level. The behavior of designed...
Dynamic voltage restore (DVR) is a well established power device able to compensate voltage disturbances, in especial voltage sags and swells, in the power system. Its main goal is to protect sensitive loads against these disturbances. For this purpose, the precise computation of the DVR compensation voltage reference is a important issue. One of the effective techniques for the reference generation...
The paper analyzes the behavior of a three-phase consumer, consisting of several personal computers connected to a transformer's secondary phases. The modalities of monitoring and recording of electrical quantities are presented in this work. The structure of the consumer is described. The recorded waveforms are analyzed. The Fast Fourier Transform (FFT) analysis allowed for the decomposition of the...
The advent of smart grids have urged a radical reappraisal of distribution networks and power quality requirements, and effective use of the network are indexed as the most important keys for smart grid expansion and deployment regardless. One of the most efficient ways of effective use of these grids would be to continuously monitor their conditions. This allows for early detection of power quality...
Nowadays, different devices are used for traffic control and accidents prevention in urban junctions. The most popular systems for vehicles detection are: inductive loop vehicle detector systems and camera detector systems. However, these systems have some weaknesses. Basically, in installation and maintenance for the first one and complex processing algorithms for the second one. This paper presents...
The monitoring and supervision of grid-connected solar and wind energy sources with consumers require further improvement of the performance and the stability of energy transfer. Therefore, the effective communication between the power generation and the supervisory nodes of power grids are necessary to manage electrical generation from renewable energy sources. The communication interface, which...
The following work presents the modeling of a grid-connected wind energy conversion system (WECS) which comprises a wind turbine, a three-phase squirrel-cage induction machine acting as a generator and a back-to-back converter. A direct torque control (DTC-SVPWM) is used on the rotor side converter. Alongside, a fuzzy based maximum power point tracking (MPPT) method is proposed in orderto better track...
Early detection of faults in the bearings of electric motors is vital to reduce maintenance costs of industrial motors. Vibration signal analysis is a well-known and widely used diagnostic approach for bearing fault identification, and usually leads to good results in terms of effectiveness and detection capability. However, small defects, at an early stage of development, can be hard to find and...
Additional losses in transformers due to harmonic currents and voltages cause further heating in their structural parts, and damage its suitable operation, thereby reducing their lifetime. This paper proposes an energy efficiency study in a three-phase dry-type transformer, which compares temperature measurements obtained from a 10kVA three-phase dry transformer on both sinusoidal and non-sinusoidal...
Nowadays a SVC at the Bom Jesus da Lapa (BJL) substation (250 MVAr) is utilized to control voltage at the Southeast/Northeast interconnection. This paper has two purposes. One is to show the technical possibility to substitute the Static VAR Compensator (SVC) by a synchronverter. Secondly, that the synchronverter mitigates electromechanical oscillations. A control strategy is utilized to damp the...
This paper presents a novel architecture of a bidirectional bridgeless interleaved converter for battery chargers of electric vehicles (EVs). The proposed converter is composed by two power stages: an ac-dc converter that is used to interface the power grid and the dc-link, and a dc-dc converter that is used to interface the dc-link and the batteries. The ac-dc converter is an interleaved bridgeless...
The study of a totally passive snubber applied to the T-type NPC converter is presented in this paper. The snubber circuit aids all commutations in all the switches. The voltage across the switches is clamped in a value close to half of the total input voltage. The description of the operation is presented in this paper.
This paper presents the novel topology of Photo Voltaic (PV) power generation system with simple Maximum Power Point Tracking (MPPT) algorithm in voltage operating mode. Power circuit consists of high output voltage DC-DC boost converter which maximizes the output of PV panel. Usually traditional DC-DC boost converters are used for such application, but they are not the most suitable solution due...
This paper presents a novel concept of unidirectional bridgeless combined boost-buck converter for electric vehicles (EVs) battery chargers. The proposed converter is composed by two power stages: an ac-dc front-end converter used to interface the power grid and the dc-link, and a dc-dc back-end converter used to interface the dc-link and the batteries. The ac-dc converter is a bridgeless boost-type...
Shading causes significant reduction in energy production in photovoltaic (PV) systems. The negative effects caused by shadowing can be reduced through different techniques, among them, the reconfiguration of PV array electrical connections, stands out. This paper presents an overview of the main techniques used to perform the photovoltaic array reconfiguration, as well as the key features of each...
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