Orientador: Prof. Dr. Claudionor Francisco do Nascimento / Dissertação (mestrado) - Universidade Federal do ABC, Programa de Pós-Graduação em Engenharia Elétrica, 2014. / Os sistemas de distribuição de energia elétrica, de um modo geral, são radiais. Estes sistemas podem possuir problemas de qualidade da energia elétrica em suas barras, tais como os desequilíbrios de tensão e de corrente. Ademais, as redes de distribuição podem conter uma grande quantidade de cargas monofásicas e trifásicas desequilibradas, indutivas e não lineares, o que pode resultar nos seguintes problemas: baixo fator de potência, desequilíbrio de tensão e distorção harmônica. Nesse sentido, devido à dinâmica destas cargas e a ocorrência de fenômenos, como afundamento de tensão por partidas de grandes motores e curtos-circuitos, há a necessidade de solução destas anormalidades, com respostas rápidas de estabilização. De maneira a atender a esta necessidade, os resultados das recentes pesquisas baseadas na eletrônica de potência têm proporcionado a utilização de equipamentos capazes de trabalhar em sistemas de potência de alta tensão. Esse avanço permite aplicações de dispositivos FACTS (Flexible Alternating Current Transmission Systems) nas operações de flexibilidade e mitigação de problemas comuns às redes de energia elétrica de transmissão e de distribuição, melhorando, assim, a qualidade da energia elétrica, o que aumenta a confiabilidade destes sistemas. Com este propósito, o presente trabalho tem como objetivo principal o estudo e a modelagem de um DSTATCOM (Distribution Static Compensator) em um sistema de distribuição de energia elétrica com variações de tensão, avaliando os possíveis benefícios proporcionados a este sistema. Os resultados de simulação foram obtidos com o auxílio do software MatLab/Simuling. / Distribution systems of electric power, in general, are radial. These systems have power quality problems in their power bars, such as the voltage variations. Moreover, the distribution networks contain a large amount of single-phase and three-phase unbalanced loads, inductive and non-linear, which may result in the following problems: low power factor, voltage unbalance, and harmonic distortion. Accordingly, due to the dynamic loads and the occurrence of these phenomena, such as voltage sag matches by large motors and short circuits, there is a need for solution of these abnormalities, with responsive stabilization. In order to meet this need, the results of recent research based on power electronics have provided the use of equipment to work on systems of high voltage power. This advancement allows applications FACTS devices (Flexible Alternating Current Transmission Systems) flexibility in operations and mitigation of problems common to the networks of electricity transmission and distribution, thus improving the quality of electric power, which increases the reliability of these systems. For this purpose, the present work has as main objective the study and modeling of a DSTATCOM (Distribution Static Compensator) in a system of electricity distribution, evaluating the possible benefits provided to the electric power system. The simulation results were obtained with the aid of software Matlab/Simuling. The effectiveness of the work has been proven since the DSTATCOM installed, the distribution network operated within established standards.

En esta Tesis ha sido analizado el control de la màquina sincrónica de rotor bobinado actuando en isla. Para esta configuración, la velocidad mecànica determina la frecuencia, y la tensión de rotor se utiliza para fijar la amplitud de la tensión de estator. Debido a que la constante de tiempo eléctrica es mucho más ràpida comparada con la constante de tiempo mecánica, la velocidad mecánica fue considerada constante y externamente regulada y la investigación se enfocó en la regulación de la amplitud de la tensión de estator.Cuatro diferentes controladores basados en técnicas de modos deslizantes fueron diseñados en el marco de referencia dq. Las leyes de control obtenidas regulan la amplitud de la tensión de estator independientemte del valor de la carga. Adicionalmente, sólo las medidas de tensión y posición del rotor (para calcular la transformada dq) son necesarias. La estabilidad de los puntos de equilibrio obtenidos fueron probados al menos utilizando anàlisis de pequeña señal.Se realizó la validación por simulación y experimental de cada controlador en diferentes escenarios. Los resultados obtenidos validan los diseños y muestran las principales ventajas y desventajas de el sistema en lazo cerrado.El capítulo 2 cubre los problemas de modelado de la màquina sincrónica de rotor bobinado. Partiendo de las ecuaciones trifásicas generales, y utilizando la transformada de Park, se encontraron el modelo en dq del generador sincrónico de rotor bobinado (WRSG) en isla, alimentando tanto carga resistiva como inductiva. Los puntos de equilibrio del sistema obtenido fueron analizados y calculados, luego se definió el objetivo de control. Finalmente, se obtuvieron modelos lineales aproximados y sus respectivas funciones de transferencia.Los controladores PI son los más usados en la industria porque ofrecen buen desempeño y son sencillos de implementar. En el capítulo 3, se obtuvieron las reglas de sintonización para el controlador PI, y se analizaron estos resultados con el objetivo de proponer nuevos controladores que mejoraran el desempeño de la clásica aproximación PI.El esquema de control en modos deslizantes para la WRSG conectada a una carga resistiva fue diseñado en el capítulo 4. Éste, también incluye un completo análisis de estabilidad del sistema en lazo cerrado. El capítulo 5 presenta dos diseños basados en modos deslizantes para regular la amplitud de la tensión de estator para el WRSG actuando en isla. Ambos diseños usan la componente d de la tensión de estator en la función de conmutación. El primer caso es un control anidado, donde un lazo externo PI es añadido para proveer la referencia de la componente d de la tensión. En la segunda aproximación un término integral es añadido a la superficie de conmutación.El caso de alimentar una carga inductiva es estudiado en el capítulo 6. El controlador requiere una extensión dinámica debido a que la amplitud de la tensión de estator es una salida de grado relativo cero. Como resultado, un controlador robusto, que no depende de los parámetros de la máquina ni de los valores de carga es obtenido. En el capítulo 7 los resultados de simulación y experimentales para los controladores diseñados para el WRSG actuando en isla son presentados. En primer lugar, una descripción completa del banco es presentada. Esta incluye detalles de la etapa de adquisición de datos y de la DSP utilizada. En segundo lugar, se hace la descripción del procedimiento de simulación. Luego, las simulaciones y experimentos, que contienen diferentes escenarios, con cambios de referencia y variaciones de carga para cada controlador son presentados. / The control of the stand-alone the wound rotor synchronous generator has been analyzed in this dissertation. For this islanded configuration, the mechanical speed determines the frequency, and the rotor voltage is used to set the stator voltage amplitude. Due to the electrical time constant is so fast compared with the mechanical time constants, the mechanical speed was considered constant and externally regulated and the research was focused on the stator voltage amplitude regulation.Four different controllers based on sliding mode control techniques were designed in the dq reference frame. The obtained control laws regulate the stator voltage amplitude irrespectively of the load value. Furthermore, only voltage and rotor position measures (to compute the dq transformation), are required. The stability of the obtained equilibrium points was proved at least using small-signal analysis. Simulation and experimental validation of each controller containing several scenarios were carried out. The obtained results validate the designs and show the main advantages and disadvantages of each closed loop system. Chapter 2 covers the modeling issues of the wound rotor synchronous machine. From the general three-phase dynamical equations, and using the Park transformation, the dq-model of the stand-alone wound rotor synchronous generator feeding both a resistive and an inductive load are obtained. Equilibrium points of the obtained systems are analyzed and, after defining the control objective, the desired equilibrium points are computed.Finally, linear approximated models are obtained and their transfer functions are also presented.PI controllers are the most used in the industry because they offers good performance and are easily implementables. In Chapter 3 we obtain the tuning rule for the PI controller, and we analyze these results in order to propose new controllers which improve the classic PI approach.The sliding mode control scheme for the WRSG connected to a resistive load is designed in Chapter 4. It also includes a complete stability analysis of the closed loop system. Chapter 5 presents two sliding mode designs to regulate the stator voltage amplitude for a stand-alone wound rotor synchronous generator. Both use the stator voltage d-component error in the switching function. The first case is a nested controller, where an outer PI loop is added to provide the proper d-voltage component reference. In the second approach an integral term is added to the switching function. The case of feeding an inductive load is studied in Chapter 6. The controller introduces a dynamic extension because the stator voltage amplitude is a zero relative degree output. As result, a robust controller, which neither depends on the machine parameters nor on the load values, is obtained. In Chapter 7 the simulation and the experimental results of the designed controllers for the stand-alone wound rotor synchronous generator are presented. Firstly, a complete description of the bench is provided. It also includes details of the data acquisition stage and the used DSP card. Secondly, the description of the simulation procedure is commented. Then, the simulation and experiments which contains several scenarios, with reference change and load variations evaluated for each controller are presented.

We demonstrate a new approach for fabricating alternating current driven organic electroluminescent devices using the concept of doping in organic semiconductors. Doped charge transport layers are used for generation of charge carriers within the device, hence eliminating the need for injecting charge carriers from external electrodes. The device is an organic-inorganic hybrid: We exploit the mechanical strength and chemical stability of inorganic semiconductors and combine it with better optical properties of organic materials whose emission color can be chemically tuned so that it covers the entire visible spectrum. The device consists of an organic electroluminescence (EL) layer composed of unipolar/ambipolar charge transport materials doped with organic dyes (10 wt% ) as well as molecularly doped charge generation layers enclosed between a pair of transparent insulating metal oxide layers. A transparent indium doped tin oxide (ITO) layer acts as bottom electrode for light outcoupling and Aluminium (Al) as top reflective electrode. The electrodes are for applying field across the device and to charge the device, instead of injection of charge carriers in case of direct current (DC) devices. Bright luminance of up to 5000 cd m-2 is observed when the device is driven with an alternating current (AC) bias. The luminance observed is attributed to charge carrier generation and recombination, leading to formation of excitons within the device, without injection of charge carriers through external electrodes.

An efficient Light Emitting Diode (LED) lamp driver circuit is proposed for retrofitting the conventionally used incandescent lamps with existing TRIAC dimmer. The dimming feature in a wide range of firing angle from 30¢X to 130¢X can be accomplished by means of double pulse-width modulation (DPWM) and analog current regulation. The LED lamp driver adopts a flyback converter with an auxiliary active power MOSFET for synchronous switch and an associated inductor for zero voltage switching (ZVS), leading to lower switching loss and thus achieving a higher circuit efficiency. In the thesis, the mode operation of the driver circuit is analyzed and the design equations are derived accordingly. A laboratory circuit is designed for an 50 W LED lamp which is composed of 45 high-brightness white LEDs in series. Experiments are carried out to test the circuit performances with two dimming schemes. The experimental results indicate that the driver can achieve a circuit efficiency of 95 % at the rated output. When the LED lamp is dimmed, the circuit efficiency with DPWM is higher than that with the analog current regulation. On the other hand, the LED lamp dimmed by analog current regulation has a higher efficiency but a less color shift by DPWM.

The objective of the proposed research is to investigate feasible approaches to dynamic control of the power grid. Growth in the demand for electric power, and an increase in the penetration of renewable energy resources are causing congestion on an already aging power grid. Conventional grid control involves the use of static assets that operate on long time scales. These assets provide no dynamic control on the grid, and are typically used for scheduled support. Existing solutions (FACTS devices) to dynamic grid control have seen minimal market penetration because of high cost and low reliability. The proposed research provides a solution for dynamic control of the power grid that augments existing grid assets with a thin AC converter (TACC) to realize enhanced dynamic control. The TACC is a direct AC converter with filter elements and no bulk energy storage that dynamically reflects the asset value on the grid. The converter has a fail-normal mode of operation that returns the asset to its initial operating state, thereby not degrading system reliability. Some applications of TACCs include Inverter-Less STATCOMs and Controllable Network Transformers, which are realized by augmenting shunt VAR capacitors and load tap changers respectively. The principle of virtual quadrature sources is proposed to enable conditioning of AC voltages and currents. The concept is a novel method to realize control of phase angle and, or harmonics in single-phase AC converters, with no bulk energy storage. This concept is used to control the TACC and provides the asset with significantly enhanced control capabilities. Scaling of the TACC to utility voltage and power levels has been addressed by proposing a novel multilevel direct AC converter. The concept proposes the use of commercially available low cost semiconductor devices to realize high power converters. The specific application chosen to validate the concept of TACCs, through a medium voltage design, is the Inverter-less STATCOM.

Οι συνεχώς αυξανόμενες ενεργειακές απαιτήσεις της σύγχρονης κοινωνίας σε συνδυασμό με τις ραγδαίες κλιματικές αλλαγές μας οδηγούν στην ανάγκη παραγωγής ηλεκτρικής ενέργειας με όσο το δυνατό πιο οικονομικό και φιλικό προς το περιβάλλον τρόπο. Έτσι, οι Ανανεώσιμες Πηγές Ενέργειας αποκτούν ολοένα και μεγαλύτερο μερίδιο στην παραγωγή ηλεκτρικής ενέργειας, αλλάζοντας συνεχώς τον παγκόσμιο ενεργειακό χάρτη. Τα αιολικά συστήματα, τα οποία αξιοποιούν την κινητική ενέργεια του ανέμου, είναι ένα είδος ΑΠΕ. Στην παρούσα εργασία μελετάμε ένα αιολικό σύστημα, το οποίο αποτελείται από μία ανεμογεννήτρια μεταβλητών στροφών που χρησιμοποιεί μία σύγχρονη μηχανή μόνιμου μαγνήτη, έναν μετατροπέα πηγής τάσης, ένα R-L φίλτρο στην πλευρά του δικτύου και μία γραμμή μεταφοράς μικρού μήκους. Η αυξημένη αξιοπιστία και απόδοση της ΣΜΜΜ την καθιστούν ιδιαίτερα ελκυστική λύση για τα αιολικά συστήματα. Στην εργασία αυτή προσομοιώνουμε σε περιβάλλον Matlab/Simulink το σύστημα που περιγράψαμε παραπάνω. Εφαρμόζοντας τις κατάλληλες τεχνικές ελέγχου από την πλευρά της μηχανής προσπαθούμε να πετύχουμε μέγιστη απομάστευση ισχύος από τον άνεμο, ενώ στην πλευρά του δικτύου προσπαθούμε μέσω άμεσου ελέγχου ροής ισχύος να πετύχουμε μοναδιαίο συντελεστή ισχύος με ταυτόχρονη ρύθμιση της τάσης της dc διασύνδεσης. Στη συνέχεια, μέσω ενός πρόσθετου ελέγχου προσπαθούμε να κρατήσουμε την τάση στην έξοδο του φίλτρου σταθερή, κατά τη διάρκεια πτώσης της τάσης του δικτύου. Τέλος, παραθέτουμε τα αποτελέσματα της προσομοίωσης μαζί με έναν σύντομο σχολιασμό και τα συμπεράσματα. / The continuously increasing energy requirements of modern society combined with the rapid climate changes lead us to the need to produce electrical energy in a more economic and environmentally friendly way. Thus, the Renewable Energy Sources gain an increasing share of electrical energy production, constantly changing the global energy map. Wind power systems, which utilize the kinetic energy of the wind, are a kind of RES. In this thesis we study a wind power system, which comprises a variable speed wind turbine, which uses a permanent magnet synchronous machine, a voltage source converter, an R-L filter in the grid side and a short transmission line. The increased reliability and performance of PMSG make it particularly attractive solution for wind power systems. In this thesis we simulate in Matlab/Simulink environment the system described above. Applying appropriate control techniques on the machine side we try to achieve maximum power harvesting from the wind, while on the grid side we try through direct power flow control to achieve unit power factor with simultaneous control of the dc link voltage. Then, using an additional control we try to keep constant the voltage at the end of the R-L filter during a grid voltage drop. Finally, we present the simulation results along with a brief commentary and the conclusions.

Thesis (MScEng)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: The worldwide increase in the popularity of high voltage direct current (HVDC) power transmission application has led to questions regarding the performance of high voltage alternating current (HVAC) insulators when energized under HVDC excitation. These questions have led researchers conduct numerous research projects worldwide. A particular question NamPower (the power utility in Namibia) has faced is: how do these insulators perform and age when energized under HVDC excitation in heavily polluted environments? This question was only partly answered by some insulator ageing tests conducted under laboratory conditions for HVDC excitation. However, the natural ageing tests on insulators, which are preferred, have to date been confined predominantly to HVAC excitation voltages. Thus, this research was initiated to investigate the natural ageing performance of insulators under both HVAC and HVDC excitations, when subjected to harsh marine pollution environments. This research project involved performance and ageing tests on three identical sets of line insulators made from different insulator materials, energised under HVAC and both polarities HVDC excitations respectively. The tests were conducted at Koeberg insulator pollution test station (KIPTS), which is a natural marine pollution insulator test station located near Cape Town, along the west coast of South Africa, approximately 50 m from the sea. The set of insulators consisted of EPDM silicone alloy rubber, HTV silicone rubber, RTV silicone rubber coated porcelain, Porcelain and Glass insulators. The HVAC excitation voltage was chosen as 12.7 kV r.m.s. phase-to-ground and it was decided to use a HVDC excitation voltage equal to this value. The research results showed that the insulators made from HTV silicone rubber performed better than the insulators made from EPDM silicone alloy rubber under all excitation voltages. It is also showed that RTV silicone rubber coated porcelain insulators performed better than Glass and Porcelain insulators under all excitation voltages. / AFRIKAANSE OPSOMMING: Die wêreld wye toename in gewildheid van hoë spanning gelyk stroom (HSGS) krag transmisie aplikasie het gelei na vrae oor die effektieweteit van hoë spanning wissel stroom (HSWS) insolators in HSGS aplikasies. Hierdie vrae het gelei na baie navorsings projekte. Een vraag waarmee NamPower (die krag voorsienings maatskapy in Namibia) gekonfronteer was, was hoe gaan die insolators wat onderworpe is aan ’n HSGS toevoer reageer in ’n baie besoedelde omgewing. Hierdie vraag was slegs gedeeltelik beantwoord deur verouderings toetse op insolators wat gedoen is in ’n labaratorium met ’n HSGS toevoer. Inteendeel, die meeste natuurlike verouderings toetse op insolators, soos verkies, is meestal gedoen met ’n HSWS toevoer. Om hierdie rede was hierdie navorsing begin om natuurlike verouderings toetse te doen op insolators onderworpe beide aan HSWS en HSGS toevoere binne ’n marien besoedelde omgewing. Hierdie navorsings projek gaan oor prestering en verouderings toetse op drie, identiese, transmissie lyn insolator stelle, wat onderskeidelik onderworpe was aan HSWS en beide polariteite HSGS toevoere. Die toetse was gedoen by Koeberg insolator besoedeling toets stasie (KIBTS) wat naby Kaapstad geleë is langs die weskus van Suid Africa omtrent 50 m van die see. ’n Stel toets insolators bestaan uit EPDM silikon allooi rubber, HTV silikon rubber, RTV silikon rubber bedekte porselein, Porselein en Glas insolators. Die HSWS waarde waarmee die insolators getoets was, was 12.7 kV w.g.k., fase-na-grond, en dit was besluit om ’n HSGS waarde gelyk aan hierdie spannings waarde te gebruik. Die navorsings resultate wys dat insolators wat gemaak is met HTV silikon rubber presteer beter as insolators wat met EPDM silikon allooi rubber gemaak is onder al die verskillende toevoere. Dit wys ook dat RTV silikon rubber bedekte porselein presteer beter as Porselein en Glas insolators onder al die verskillende toevoere.

Orientador: Madileine Francely Américo / Resumo: Os imunossupressores são utilizados após o transplante de órgãos e no tratamento de doenças autoimunes, desencadeando diversos efeitos colaterais. No esquema tríplice de imunossupressão pós-transplante, cada droga ou a combinação delas podem alterar a estrutura e/ou funcionamento do trato gastrintestinal. Apesar da importância do trato gastrintestinal e de conhecer os efeitos da ingesta oral de imunossupressores, há poucos estudos enfocando esses aspectos e vários desafios éticos para essas avaliações no homem. Desse modo, objetivou-se avaliar as alterações provocadas pela imunossupressão nos parâmetros de esvaziamento gástrico, frequência e amplitude das contrações gástricas, bem como as alterações histológicas no estômago de ratos. Para isso foram utilizados a Biosusceptometria de Corrente Alternada (BAC) e a Eletrogastrografia (EGG). No primeiro capítulo, avaliou-se individualmente sete imunossupressores de diferentes classes (Tacrolimo, Ciclosporina, Micofenolato Mofetil, Azatioprina, Sirolimo, Everolimo e Prednisona) comumente utilizados na terapia imunossupressora. Todos os imunossupressores estudados, exceto o Micofenolato Mofetil causaram alguma alteração nos parâmetros gastrintestinais analisados em ratos. Já o segundo capítulo apresenta os efeitos da terapia imunossupressora combinada, baseada em três classes de imunossupressores (inibidores da calcineurina, antimetabólitos e glicocorticoides). Um dos grupos experimentais recebeu Tacrolimo associado à Micofenolato S... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Immunosuppressants are used after organ transplantation and in the treatment of autoimmune diseases, triggering several side effects. In the triple regimen of post - transplant immunosuppression, each drug or combination of them may alter the structure and / or function of the gastroin testinal tract. Despite the importance of gastrointestinal tract and knowledge of the effects of oral intake of immunosuppressants, there are few studies focusing on these aspects and several ethical challenges for these evaluations in humans. The aim of t his study was to evaluate the effects provoked by immunosuppression in gastric emptying parameters, frequency and amplitude of gastric contractions, as well as the histological aspects in the stomach of rats. Alternating Current Biosusceptometry (BAC) and Electrogastrography (EGG) were used. In the first chapter, seven immunosuppressants from different classes (Tacrolimus, Cyclosporine, Mycophenolate Mofetil, Azathioprine, Sirolimus, Everolimus and Prednisone) commonly used in immunosuppressive therapy were evaluated individually. All immunosuppressants studied except Mycophenolate Mofetil , caused some alteration in the gastrointestinal parameters analyzed in rats. The second chapter presents the effects of combined immunosuppressive therapy based on three c lasses of immunosuppressants (calcineurin inhibitors, antimetabolites and glucocorticoids). One of the experimental groups received Tacrolimus associated with Mycophenolate Sodium and Pr... (Complete abstract click electronic access below) / Doutor

Orientador: José Ricardo de Arruda Miranda / Resumo: Inflammatory bowel disease (IBD) is an idiopathic gastrintestinal tract disease that affects a large part of the world population and has its symptoms related to changes in colon motility. However, the evolution of these changes is not completely understood, and may be related to symptoms that appear in stages when the disease is apparently controlled. The objective of this work was to perform a long-term evaluation of the mechanical and electrical aspects of colonic contractility during the model of inflammation induced by trinitrobenzene sulfonic acid (TNBS) in rats. This work applied an efficient and low invasive methodology associating mechanical, electrical, chemical and histological information. The contractility and inflammatory parameters were acquired in the same animal at six different times: before induction of TNBS (control) and at 2, 5, 8, 11 and 14 days thereafter. The mechanical activities were acquired by Alternating Current Biosusceptometry (ACB) and subdivided in Rhythmic Propagation Ripples (RPR) and Rhythmic Propulsive Motor Complex (RPMC). We recorded the electrical activity by electromyography (EMG) and evaluated the inflammation processes determining the myeloperoxidase activity (MPO) in the feces. Additionally, we compared the thickness of colon layers throughout the inflammation by histopathological analyzes. Our results showed transient changes in MPO activity levels and frequency of RPMC contraction, while RPR and electrical activity underwent perma... (Resumo completo, clicar acesso eletrônico abaixo) / Doutor

Fundação de Apoio a Pesquisa e à Inovação Tecnológica do Estado de Sergipe - FAPITEC/SE / Studies report that alternating current is more effective in promoting analgesia than low frequency pulsed currents. However, the hypoalgesic potential and the clinical use of the medium frequency alternating current in kHz (Aussie) are based on hypothetical mechanisms of action. The present study aimed to investigate the hypoalgesic potential of the Aussie Current (AC) in healthy individuals. Eighty-one healthy subjects underwent electrostimulation by using kilohertz-frequency alternating current for 20 minutes and were randomized into three distinct groups (1 kHz, 4 kHz or placebo). Pressure pain threshold (PPT, algometry), conditioned pain modulation (CPM, ischemic pain in the contralateral upper limb and algometry), temporal summation (TS, algometry) were measured before and after intervention, the level of anxiety (STAI-T and STAI-E), in turn, was measured only at the pre-intervention. At the end of the protocol, subjects were questioned regarding the treatment they received and the comfort during the stimulation (numerical scale) and, similarly, investigators were questioned about their expectation related to subject’s allocation groups. These responses were recorded and used to test the adequacy of the masking procedure regarding the subject and the investigator. The level of anxiety evaluated did not a statistically significant difference between the groups, who received the active AC (1 kHz / 4kHz) or placebo, (p> 0.05). Regarding PPT, there was no statistically significant difference in the active AC 1 kHz, active 4 kHz and placebo groups at any of the moments evaluated. The active group AC 4 kHz presented a statistically significant reduction in the amplification of pain intensity, verified by the reduction of perceived pain intensity, in the tenth (p = 0.02), twentieth (p = 0.01) and thirtieth second (p = 0.001) in the TS test. The active group AC 1 kHz, in turn, presented significant reduction of pain intensity only at the end of the measurement (thirty-second, p = 0.01). In the evaluation of the CPM, there was no significant difference of the PPT, during induction of ischemia, in the AC active groups 4 kHz and active AC 1 kHz, before and after intervention (p> 0.05). However, in the placebo group there was a significant reduction in PPT, only during induced ischemia, both before and after intervention (p = 0.01). Thus, our study provides evidence that kilohertz-frequency AC current, especially when used with an equivalent 4 kHz frequency, presents hypoalgesic effect, having having possible inhibitory action in the Central Nervous System (CNS). / Estudos relatam que a corrente alternada é mais eficaz em promover analgesia que as correntes pulsadas de baixa frequência. Porém, o potencial hipoalgésico e a utilização clínica da corrente alternada de média frequência em kHz (Aussie) são baseados em mecanismos de ação hipotéticos. O presente estudo teve, como objetivo, investigar o potencial hipoalgésico da corrente Aussie (CA) em indivíduos saudáveis. Oitenta e um sujeitos saudáveis foram submetidos à eletroestimulação com corrente alternada de média frequência em quilohertz durante 20 minutos, sendo randomizados em três grupos distintos (1 kHz, 4 kHz ou placebo). Limiar de dor por pressão (LDP, algometria), modulação condicionada da dor (MCD, dor isquêmica no membro superior contralateral e algometria), somação temporal (ST, algometria) foram mensurados antes e após intervenção, o nível de ansiedade (IDATE-T e IDATE-E), por sua vez, foi mensurado apenas no momento pré-intervenção. Ao final do protocolo, os sujeitos foram questionados com relação ao tratamento que receberam e o conforto durante a estimulação (escala numérica) e, similarmente, os avaliadores sobre sua expectativa relacionada ao grupo de alocação dos sujeitos. Estas respostas foram registradas e usadas para testar a adequação do procedimento de mascaramento referente ao sujeito e ao investigador. O nível ansiedade, avaliado no momento pré-intervenção, não diferiu entre os grupos que receberam a CA ativa (1 kHz/ 4 kHz) ou placebo, sendo p>0,05. Em relação ao LDP, não houve diferença estatisticamente significativa nos grupos de intervenção CA ativa 1kHz, ativa 4 kHz e placebo em nenhum dos momentos avaliados. O grupo ativo CA 4 kHz apresentou redução estatisticamente significativa da amplificação da intensidade da dor, verificada pela redução da intensidade de dor percebida, no décimo (p=0,02), vigésimo (p=0,01) e trigésimo segundos (p=0,001), no teste de ST. O grupo ativo CA 1 kHz, por sua vez, apresentou redução significativa da intensidade de dor apenas no final da mensuração (trigésimo segundo; p=0,01). Na avaliação da MCD, não houve diferença significativa do LDP, durante a indução de isquemia, nos grupos CA ativo 4 kHz e CA ativo 1 kHz, no momento antes e após intervenção (p>0,05). No entanto, no grupo placebo, houve redução significativa do LDP, apenas durante a isquemia induzida, comparando pré e pós-intervenção (p=0,01). Dessa forma, o nosso estudo, fornecem evidências de que a corrente aussie, principalmente, quando utilizada com frequência equivalente 4 kHz, apresenta resultados hipoalgésicos, tendo possível ação inibitória no sistema nervoso central (SNC).