Uma nova metodologia de projeto e controle para o inversor Boost (CSI) monof��sico, para o aproveitamento de fontes alternativas e renov��veis de energia el��trica

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Retificador boost entrela��ado com elevado fator de pot��ncia e sem ponte de diodos

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

Retificador trif��sico de 18 pulsos com est��gio CC controlado por histerese constante

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

An��lise do suporte de reativos em um sistema el��trico de pot��ncia com link HVDC

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

C��lula de comuta����o de tr��s estados aplicada ao pr��-regulador boost de est��gio ��nico e elevado fator de pot��ncia

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Redu����o de harm��nicos de corrente em retificadores de m��ltiplos pulsos: generaliza����o das conex��es diferenciais

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Retificador entrela��ado boost, no modo de condu����o descont��nua, com t��cnica de corre����o da corrente de entrada e elevado fator de pot��ncia, para aplica����o em sistema tr��lebus

Coordena����o de Aperfei��oamento de Pessoal de N��vel Superior (CAPES)

Utiliza����o de magnetorresistores no desenvolvimento de novas t��cnicas para aplica����es em gastroenterologia

Funda����o de Amparo �� Pesquisa do Estado de S��o Paulo (FAPESP)

Comparative analysis between overlapping and non-overlapping operation modes for the PWM buck converter using the three-state switching cell

Conselho Nacional de Desenvolvimento Cient��fico e Tecnol��gico (CNPq)

Proposta de uma metodologia de rebobinamento para converter motor de indu����o trif��sico em monof��sico

This paper proposes the conversion of a three-phase induction motor into single phase through rewinding its stator. It presents a methodology to calculate this rewinding process considering the constructive parameters of the, such as number of slots and number of poles, for instance. The operating principles of DC motors are highlighted to introduce the logic involved in the calculation of lap and wave windings. The construction of the stator three-phase induction motor generally uses the lap winding, which is also used in single phase to perform the conversion. The rewinding process is widely used for reconstruction of industrial and residential electric motors that have suffered damage or present flaws with use. Therefore, many three-phase electric motors that are discarded or disposed of could be recovered by the method described in this work for a purpose that contributes to energy efficiency or simply saving resources in single-phase uses

Retificador entrela��ado com elevado fator de pot��ncia para opera����o de um ve��culo tr��lebus alimentado por redes em CA Ou CC

This paper presents the development and the main results for an interleaved boost rectifier operating as a special input power stage for a trolleybus type vehicle, allowing its feeding by alternate current (AC) or direct current (DC) distribution power systems. When feeding with two wires (single phase) alternate current distribution system, the converter accomplish active power factor correction, providing a relatively sinusoidal current with low total harmonic distortion (THD) and fully complying with IEC 61000-3-4 standards. In addition, a management control system promotes the required automatic operation changes for the proposed rectifier when the vehicle is changing from the DC distribution power system to the AC distribution power system and vice-versa, keeping its original electrical DC system characteristics for the adjustable speed driver sub-system. The main experimental results for a prototype rated at 150kW are presented, considering its application for a trolleybus with DC adjustable speed driver, demonstrating the proposed converter benefits and the possibility of AC feeding system for trolleybus type vehicle.

Tap-Off Power From the Overhead Shield Wires of an HV Transmission Line

In recent years, there was an increase of ancillary service loads, such as signaling systems, inspection robots, surveillance cameras, and other monitoring devices distributed along high-voltage transmission lines which require low-power dc voltage supplies. This paper investigates the use of the induced voltage in the shield wires of an overhead 525 kV transmission line as a primary power source. Since phase current variations throughout the day affect the induced voltage in the overhead ground wire, a step-down dc-dc converter is used after rectification of the ac voltage to provide a regulated dc output voltage. The initial encouraging results obtained indicate that this form of power supply can be a feasible and cost-effective alternative for feeding small ancillary service loads. The simulation results are validated by field measurements as well as the installation of a 200 W voltage stabilization system prototype.

A multilevel converter structure for grid-connected PV plants

A new conversion structure for three-phase grid-connected photovoltaic (PV) generation plants is presented and discussed in this Thesis. The conversion scheme is based on two insulated PV arrays, each one feeding the dc bus of a standard 2-level three-phase voltage source inverter (VSI). Inverters are connected to the grid by a traditional three-phase transformer having open-end windings at inverters side and either star or delta connection at the grid side. The resulting conversion structure is able to perform as a multilevel VSI, equivalent to a 3-level inverter, doubling the power capability of a single VSI with given voltage and current ratings. Different modulation schemes able to generate proper multilevel voltage waveforms have been discussed and compared. They include known algorithms, some their developments, and new original approaches. The goal was to share the grid power with a given ratio between the two VSI within each cycle period of the PWM, being the PWM pattern suitable for the implementation in industrial DSPs. It has been shown that an extension of the modulation methods for standard two-level inverter can provide a elegant solution for dual two-level inverter. An original control method has been introduced to regulate the dc-link voltages of each VSI, according to the voltage reference given by a single MPPT controller. A particular MPPT algorithm has been successfully tested, based on the comparison of the operating points of the two PV arrays. The small deliberately introduced difference between two operating dc voltages leads towards the MPP in a fast and accurate manner. Either simulation or experimental tests, or even both, always accompanied theoretical developments. For the simulation, the Simulink tool of Matlab has been adopted, whereas the experiments have been carried out by a full-scale low-voltage prototype of the whole PV generation system. All the research work was done at the Lab of the Department of Electrical Engineering, University of Bologna.

Circuiti per il miglioramento della qualit�� di sorgenti dc

Tutti gli apparati elettronici richiedono un'alimentazione in tensione continua. Qualunque sia la fonte di energia elettrica, una batteria (in DC) o la rete di distribuzione (in AC), l���alimentatore ha il compito di regolare la tensione continua di uscita per consentire il corretto funzionamento del dispositivo alimentato. La stabilizzazione della tensione DC in uscita deve avvenire nonostante la presenza di ripple e di disturbi sulla alimentazione primaria, di ampie variazioni sulle correnti assorbite dal carico, di ampie escursioni di temperatura e deve essere garantita nel tempo, anche a fronte di sostituzione di alcuni componenti del circuito. In questa tesi si prenderanno in considerazione i regolatori lineari. Sebbene si tratti di circuiti che operano in condizioni di linearit�� e quindi, quasi per definizione, poco efficienti, in realt�� il loro impiego diventa quasi obbligatorio per applicazioni in cui �� richiesta una tensione di alimentazione poco rumorosa. Se utilizzati a valle di un alimentatore switching possono aumentare notevolmente la qualit�� della tensione di uscita operando con livelli di efficienza e di dissipazione del tutto accettabili e con minimo aumento di costo del sistema. Gli alimentatori lineari non sono dunque ���superati��� dai pi�� recenti alimentatori switching ma sono, piuttosto, ���alternativi��� e, in molti alimentatori moderni, di complemento. Per questo motivo, anche di recente, sono stati sviluppati e trovano importanti quote di mercato innovative architetture di regolatori lineari dalle prestazioni molto migliorate e vi sono circuiti come il regolatore di John Linsley Hood che non possono non suscitare il pi�� vivo interesse della comunit�� audiofila

Adaptive control of sinusoidal brushless DC motor actuators

Electrical Power Assisted Steering system (EPAS) will likely be used on future automotive power steering systems. The sinusoidal brushless DC (BLDC) motor has been identified as one of the most suitable actuators for the EPAS application. Motor characteristic variations, which can be indicated by variations of the motor parameters such as the coil resistance and the torque constant, directly impart inaccuracies in the control scheme based on the nominal values of parameters and thus the whole system performance suffers. The motor controller must address the time-varying motor characteristics problem and maintain the performance in its long service life. In this dissertation, four adaptive control algorithms for brushless DC (BLDC) motors are explored. The first algorithm engages a simplified inverse dq-coordinate dynamics controller and solves for the parameter errors with the q-axis current (iq) feedback from several past sampling steps. The controller parameter values are updated by slow integration of the parameter errors. Improvement such as dynamic approximation, speed approximation and Gram-Schmidt orthonormalization are discussed for better estimation performance. The second algorithm is proposed to use both the d-axis current (id) and the q-axis current (iq) feedback for parameter estimation since id always accompanies iq. Stochastic conditions for unbiased estimation are shown through Monte Carlo simulations. Study of the first two adaptive algorithms indicates that the parameter estimation performance can be achieved by using more history data. The Extended Kalman Filter (EKF), a representative recursive estimation algorithm, is then investigated for the BLDC motor application. Simulation results validated the superior estimation performance with the EKF. However, the computation complexity and stability may be barriers for practical implementation of the EKF. The fourth algorithm is a model reference adaptive control (MRAC) that utilizes the desired motor characteristics as a reference model. Its stability is guaranteed by Lyapunov���s direct method. Simulation shows superior performance in terms of the convergence speed and current tracking. These algorithms are compared in closed loop simulation with an EPAS model and a motor speed control application. The MRAC is identified as the most promising candidate controller because of its combination of superior performance and low computational complexity. A BLDC motor controller developed with the dq-coordinate model cannot be implemented without several supplemental functions such as the coordinate transformation and a DC-to-AC current encoding scheme. A quasi-physical BLDC motor model is developed to study the practical implementation issues of the dq-coordinate control strategy, such as the initialization and rotor angle transducer resolution. This model can also be beneficial during first stage development in automotive BLDC motor applications.