Carlos Couto - Profile on Academia.edu (original) (raw)

Papers by Carlos Couto

A Comlbined SeriesActive Filter andPassive Filters forHarmonics,Unbalances andFlicker Compensation

Thispaperdescribes acombined operation involving a series active filter andshuntpassive filters f... more Thispaperdescribes acombined operation involving a series active filter andshuntpassive filters forthree-phase three-wire systems. Theseries active filter isabletominimize PowerQuality problems like unbalances, harmonics andflicker observed atthesystem voltages. Another taskfortheseries active filter istodamppossible resonances involving thepassive filters andthesystem impedance. Theshuntpassive filters aredesigned todrainharmonic current-components generated bytheload. Thecontrol strategy oftheseries active conditioner isbasedon theinstantaneous powertheoryon a-fl-O reference frame, together witharobust synchronizing circuit PLL(Phase-Locked- Loop).A dc-link voltage controller, applied to theseries conditioner, isalsointroduced duetothefact thatthere isonlya single capacitor attheinverter dc-side. Simulation results on PSCAD(/EMTDCTMarepresented in ordertoverify the performance involving acombined operation ofpassive andactive filters. IndexTerms - CustomPower,Power Quality, System Stability, Instantaneous PowerTheory.

A Comlbined SeriesActive Filter andPassive Filters forHarmonics,Unbalances andFlicker Compensation

Thispaperdescribes acombined operation involving a series active filter andshuntpassive filters f... more Thispaperdescribes acombined operation involving a series active filter andshuntpassive filters forthree-phase three-wire systems. Theseries active filter isabletominimize PowerQuality problems like unbalances, harmonics andflicker observed atthesystem voltages. Another taskfortheseries active filter istodamppossible resonances involving thepassive filters andthesystem impedance. Theshuntpassive filters aredesigned todrainharmonic current-components generated bytheload. Thecontrol strategy oftheseries active conditioner isbasedon theinstantaneous powertheoryon a-fl-O reference frame, together witharobust synchronizing circuit PLL(Phase-Locked- Loop).A dc-link voltage controller, applied to theseries conditioner, isalsointroduced duetothefact thatthere isonlya single capacitor attheinverter dc-side. Simulation results on PSCAD(/EMTDCTMarepresented in ordertoverify the performance involving acombined operation ofpassive andactive filters. IndexTerms - CustomPower,Power Quality, System...

3rd IFAC Workshop on Discrete-Event System Design (2006), 2006

The paper presents a novel language, MiADL, which allows the specification of a wide class of ISA... more The paper presents a novel language, MiADL, which allows the specification of a wide class of ISAs using an expressive and natural description. MiADL explores the common features of instructions to allow compact descriptions. The description's efficiency and expressiveness is demonstrated with some examples, comparing them with other related works, using a complex ISA of a contemporary real-world processor -ARM. The language allows a clear specification of complex instruction formats. Some of its syntax constructs foster the early detection of specification's incoherence improving the description's consistency.

Qualidade de energia eléctrica

In the industry of foundry, the deburring of casting pieces is an important stage. Since the piec... more In the industry of foundry, the deburring of casting pieces is an important stage. Since the piece presents edges in the junction zone of the casting moulds, those usually are not desirable and should be eliminated. For solving this problem it was idealized a robotic system capable of deburring casting pieces with minimum human intervention. Consists of an ABB robot, a table of coordinates for fixation and movement of the casting pieces, an artificial vision system for identification and quality control of the casting pieces, a Bosch high frequency straight grinder and an force sensor that closes the feedback loop of the deburring process control.

Transformerless series active power filter to compensate voltage disturbances

This paper presents a Shunt Active Power Filter that is built using a current-source inverter. Th... more This paper presents a Shunt Active Power Filter that is built using a current-source inverter. The control of the Active Filter relies in the p-q Theory with the "Sinusoidal Currents at Source" algorithm implemented. The Active Power Filter was simulated using two modulation techniques: Periodic Sampling and Carrier-Based Pulse Width Modulation (CBPWM). To assess the performance of the Active Filter, the simulations were made using two different loads. The first load was a RL balanced load. The second was a non-linear load, namely a full bridge rectifier with a RL load in the DC side. These loads allowed determining the performance of the Active Filter when compensating current harmonics and power factor, using the two modulation techniques.

77ris paper describes a data acqui.\'ition .\'olution using a single chip risc type microcontroll... more 77ris paper describes a data acqui.\'ition .\'olution using a single chip risc type microcontroller with ver)' Jew other active and passive component.\' Howevcr this solution although greatly reducing tile around. 77re need Jor thermallY stable circuits and commissioning time of wcighbridge. type equiprncnt components is minimized through lhe use oJ lhe some needs a cost effectivc solution for the load cclls data amplification chain Jor both lhe ...ignal and reJerence. proccssing so that is not uneconornical to use one per together with soflware calibration. The analog to transduccr. digital conversion is done u...ing lhe single ramp approach controlled by lhe microcontroller which Having in rnind industrial wcighing applications doe... ali lhe digital proce ing required as well a.. whcre (,()()() divisions are nccded for the equiprnent lhe serial communication with lhe external world. (external divisions) a conversion resolution of at least 77re paper also describes an example oJ soflware 60000 divisions (10 infernal divisions for cach calibration oJ a multi-loadcell weighhridge using cxternal) with 20 or more rcadings per second. ai one single processing module per sensor. lcast for static weighing applications. For dynarnic weighing a fastcr reading cate is required but with Kevwords: Data Acquisition. lntelligent Transducers. lowcr rcsolution

Multi-load cells weighting systems are based on a p/atform supported by four or more load cells, ... more Multi-load cells weighting systems are based on a p/atform supported by four or more load cells, normally in parallel inputting lhe same signal conditioning unit. Because of mechanical and electrical paralleling tuning lhe gain of a load cell affects lhe behavior of lhe others, making lhe calibration difficu/t and tedious, specially with weightbridges for cars and trucb, requiring lhe motion of heavy weights around /arge p/atforms. A so.ftware calibration can be achieved by calculation of lhe multipiying coefficients, which are given by lhe solution of a seI of linear equations, operation easiiy performed by any general purpose microcomputer. This paper shows that lhe weight output can a/so be calculated using neural networb techniques. This new calibration system is based on a very simple backpropagation neural network with as many input neurons as lhe number of load cells (four in our case), six hidden neurons and one linear output neurons. We trained lhe system byexamples (i.e. with examples data pairs) to determine lhe synapse connections.

A silicon soil moisture sensor, based in the dual-probe heat-pulse (DPHP) method, was modeled and... more A silicon soil moisture sensor, based in the dual-probe heat-pulse (DPHP) method, was modeled and simulated for achieving, with low cost, accurate and reliable measurements. This method is based on the application of a heat pulse during a fixed interval of time. The maximum rise in temperature (T m) is monitored by the measurement probe, placed at a certain distance of the heater source. A lowcost high-performance and small temperature sensor (a dynamic V P T AT generator) is required to be placed into the probe which have 0.912 mm in diameter and 20 mm long. If one considers the range of water contents, ratio of water mass to dry soil mass, in a typical agricultural soil (0.05 to 0.35 m 3 m −3), the average sensitivity of the dual probe is about 1.95 • C per unit change (m 3 m −3

This study presents a Multi-Chip-Module-based (MCM) micro-system suited for irrigation control an... more This study presents a Multi-Chip-Module-based (MCM) micro-system suited for irrigation control and management applications. The micro-system includes the soil moisture sensor and an analogue-to-digital converter with signal processing circuitry. The same basic fabrication concepts and materials which made microelectronics successful are now being adapted to making low-cost, small, and high-performance sensor systems with integrated electronics on the same micro-system. Since this sensor has low-cost fabrication for mass production, a network could be implemented in order to achieve an accurate measurement of the soil moisture at the plant root level. A dual-probe heat-pulse technique is used (measurement of the maximum temperature rise at some distance from the heater, after applying a heat-pulse) to determine the volumetric heat capacity and, hence, the water content of the soil. The sensor module is about 30 mm long, 6 mm wide, and 0.8 mm in height; the probe pitch is 3 mm allowing small-scale spatial measurements of soil moisture, which can be made near the soil surface where large root densities are found. The heater uses a nickel-chrome resistor for resistive heating (thermo resistive effect -Joule heat). The temperature sensors (probe and reference) are highaccuracy CMOS smart temperature sensors.

This paper describes a radio frequency transceiver designed in UMC RF 0.18 μm CMOS process. This ... more This paper describes a radio frequency transceiver designed in UMC RF 0.18 μm CMOS process. This process has a poly and six metal layers, allowing the use of integrated spiral inductors (with a reasonable quality factor), high resistor value (a special layer is available) and a ...

The optimization of the thermal co-evaporation process for ntype Bismuth Telluride and p-type Ant... more The optimization of the thermal co-evaporation process for ntype Bismuth Telluride and p-type Antimony Telluride onto plastic substrates (Kapton© polyimide) for thermoelectric applications is reported. Films were co-evaporated from Bismuth and Tellurium or Antimony and Tellurium to obtain Bi 2 Te 3 or Sb 2 Te 3 , respectively. The evaporation rate of each material was monitorized using a crystal oscillator sensor and the power applied to each boat was controlled with a PID algorithm, in order to achieve a precise user-defined constant evaporation rate. The influence of substrate temperature (150-300 ºC) and evaporation rate (2 Å/s-9 Å/s) on the electronic properties of the films was studied and optimized to maximize the thermoelectric figure-of-merit. Energy-dispersive X-ray spectroscopy, X-ray diffraction and Fourier-transform infrared spectroscopy confirmed the formation of Bi 2 Te 3 and Sb 2 Te 3 thin films. Seebeck coefficients (up to 250 µV/ºC), in-plane electrical resistivity (5-40 µΩ.m), Hall mobility (20-100 cm-2 .V-1 .s-1) and carrier concentration (10 19-10 21 cm-3) were measured at room temperature in films fabricated with different process parameters. Thermoelectric p-type and n-type thin films with high figures of merit, suitable for the fabrication of lateral Peltier coolers and thermal micro-generators, were obtained.

Summary: This paper describes the design, modeling and optimization of a miniaturized self-calibr... more Summary: This paper describes the design, modeling and optimization of a miniaturized self-calibrated pyrometer to detect infrared radiation (in 5-20 µm range of wavelengths) in order to measure the real temperature of objects without contact. The microsystem consists of a ...

Induction Motor Slip Control With Efficiency Optimization Using Fuzzy Logic Techniques

This paper describes a fuzzy logic based slip controller for an induction motor, with efficiency ... more This paper describes a fuzzy logic based slip controller for an induction motor, with efficiency optimization for steady state operation. The speed control is accomplished through a Mandani type fuzzy controller, with 11 rules, taking speed error (built with 5 Membership Functions ...

CONFTELE. Conference …, 2005

CMOS technology has reached its maturity. Therefore, design engineers used it for developing RF c... more CMOS technology has reached its maturity. Therefore, design engineers used it for developing RF circuits. The advantages of CMOS technology are the higher integration, low-power consumption, low-voltage supply and low-cost compared with Bipolar technology. The ...

A MCM-Based Microsystem for Soil Moisture Measurements

This work presents a Multi-Chip-Module (MCM) based microsystem for irrigation control in agricult... more This work presents a Multi-Chip-Module (MCM) based microsystem for irrigation control in agriculture. The proposed microsystem includes a soil moisture microsensor, an analog-to-digital converter, signal processing circuits (digital filtering and sensor interface) and a RF ...

International …, 2003

Actuation, monitoring, and control of fabrics feeding during high-speed sewing LF SILVA, M LIMA, ... more Actuation, monitoring, and control of fabrics feeding during high-speed sewing LF SILVA, M LIMA, H CARVALHO, AM ROCHA, FN FERREIRA, JL MONTEIRO, and C COUTO School of Engineering, University of Mmho Guimaraes, Portugal SYNOPSIS For some years now ...

Due the intensive use of power converters and other non-linear loads in industry and by consumers... more Due the intensive use of power converters and other non-linear loads in industry and by consumers in general, it can be observed an increasing deterioration of the power systems voltage and current waveforms. The presence of harmonics in the power lines results in greater power losses ...

A Comlbined SeriesActive Filter andPassive Filters forHarmonics,Unbalances andFlicker Compensation

Thispaperdescribes acombined operation involving a series active filter andshuntpassive filters f... more Thispaperdescribes acombined operation involving a series active filter andshuntpassive filters forthree-phase three-wire systems. Theseries active filter isabletominimize PowerQuality problems like unbalances, harmonics andflicker observed atthesystem voltages. Another taskfortheseries active filter istodamppossible resonances involving thepassive filters andthesystem impedance. Theshuntpassive filters aredesigned todrainharmonic current-components generated bytheload. Thecontrol strategy oftheseries active conditioner isbasedon theinstantaneous powertheoryon a-fl-O reference frame, together witharobust synchronizing circuit PLL(Phase-Locked- Loop).A dc-link voltage controller, applied to theseries conditioner, isalsointroduced duetothefact thatthere isonlya single capacitor attheinverter dc-side. Simulation results on PSCAD(/EMTDCTMarepresented in ordertoverify the performance involving acombined operation ofpassive andactive filters. IndexTerms - CustomPower,Power Quality, System Stability, Instantaneous PowerTheory.

A Comlbined SeriesActive Filter andPassive Filters forHarmonics,Unbalances andFlicker Compensation

Thispaperdescribes acombined operation involving a series active filter andshuntpassive filters f... more Thispaperdescribes acombined operation involving a series active filter andshuntpassive filters forthree-phase three-wire systems. Theseries active filter isabletominimize PowerQuality problems like unbalances, harmonics andflicker observed atthesystem voltages. Another taskfortheseries active filter istodamppossible resonances involving thepassive filters andthesystem impedance. Theshuntpassive filters aredesigned todrainharmonic current-components generated bytheload. Thecontrol strategy oftheseries active conditioner isbasedon theinstantaneous powertheoryon a-fl-O reference frame, together witharobust synchronizing circuit PLL(Phase-Locked- Loop).A dc-link voltage controller, applied to theseries conditioner, isalsointroduced duetothefact thatthere isonlya single capacitor attheinverter dc-side. Simulation results on PSCAD(/EMTDCTMarepresented in ordertoverify the performance involving acombined operation ofpassive andactive filters. IndexTerms - CustomPower,Power Quality, System...

3rd IFAC Workshop on Discrete-Event System Design (2006), 2006

The paper presents a novel language, MiADL, which allows the specification of a wide class of ISA... more The paper presents a novel language, MiADL, which allows the specification of a wide class of ISAs using an expressive and natural description. MiADL explores the common features of instructions to allow compact descriptions. The description's efficiency and expressiveness is demonstrated with some examples, comparing them with other related works, using a complex ISA of a contemporary real-world processor -ARM. The language allows a clear specification of complex instruction formats. Some of its syntax constructs foster the early detection of specification's incoherence improving the description's consistency.

Qualidade de energia eléctrica

In the industry of foundry, the deburring of casting pieces is an important stage. Since the piec... more In the industry of foundry, the deburring of casting pieces is an important stage. Since the piece presents edges in the junction zone of the casting moulds, those usually are not desirable and should be eliminated. For solving this problem it was idealized a robotic system capable of deburring casting pieces with minimum human intervention. Consists of an ABB robot, a table of coordinates for fixation and movement of the casting pieces, an artificial vision system for identification and quality control of the casting pieces, a Bosch high frequency straight grinder and an force sensor that closes the feedback loop of the deburring process control.

Transformerless series active power filter to compensate voltage disturbances

This paper presents a Shunt Active Power Filter that is built using a current-source inverter. Th... more This paper presents a Shunt Active Power Filter that is built using a current-source inverter. The control of the Active Filter relies in the p-q Theory with the "Sinusoidal Currents at Source" algorithm implemented. The Active Power Filter was simulated using two modulation techniques: Periodic Sampling and Carrier-Based Pulse Width Modulation (CBPWM). To assess the performance of the Active Filter, the simulations were made using two different loads. The first load was a RL balanced load. The second was a non-linear load, namely a full bridge rectifier with a RL load in the DC side. These loads allowed determining the performance of the Active Filter when compensating current harmonics and power factor, using the two modulation techniques.

77ris paper describes a data acqui.\'ition .\'olution using a single chip risc type microcontroll... more 77ris paper describes a data acqui.\'ition .\'olution using a single chip risc type microcontroller with ver)' Jew other active and passive component.\' Howevcr this solution although greatly reducing tile around. 77re need Jor thermallY stable circuits and commissioning time of wcighbridge. type equiprncnt components is minimized through lhe use oJ lhe some needs a cost effectivc solution for the load cclls data amplification chain Jor both lhe ...ignal and reJerence. proccssing so that is not uneconornical to use one per together with soflware calibration. The analog to transduccr. digital conversion is done u...ing lhe single ramp approach controlled by lhe microcontroller which Having in rnind industrial wcighing applications doe... ali lhe digital proce ing required as well a.. whcre (,()()() divisions are nccded for the equiprnent lhe serial communication with lhe external world. (external divisions) a conversion resolution of at least 77re paper also describes an example oJ soflware 60000 divisions (10 infernal divisions for cach calibration oJ a multi-loadcell weighhridge using cxternal) with 20 or more rcadings per second. ai one single processing module per sensor. lcast for static weighing applications. For dynarnic weighing a fastcr reading cate is required but with Kevwords: Data Acquisition. lntelligent Transducers. lowcr rcsolution

Multi-load cells weighting systems are based on a p/atform supported by four or more load cells, ... more Multi-load cells weighting systems are based on a p/atform supported by four or more load cells, normally in parallel inputting lhe same signal conditioning unit. Because of mechanical and electrical paralleling tuning lhe gain of a load cell affects lhe behavior of lhe others, making lhe calibration difficu/t and tedious, specially with weightbridges for cars and trucb, requiring lhe motion of heavy weights around /arge p/atforms. A so.ftware calibration can be achieved by calculation of lhe multipiying coefficients, which are given by lhe solution of a seI of linear equations, operation easiiy performed by any general purpose microcomputer. This paper shows that lhe weight output can a/so be calculated using neural networb techniques. This new calibration system is based on a very simple backpropagation neural network with as many input neurons as lhe number of load cells (four in our case), six hidden neurons and one linear output neurons. We trained lhe system byexamples (i.e. with examples data pairs) to determine lhe synapse connections.

A silicon soil moisture sensor, based in the dual-probe heat-pulse (DPHP) method, was modeled and... more A silicon soil moisture sensor, based in the dual-probe heat-pulse (DPHP) method, was modeled and simulated for achieving, with low cost, accurate and reliable measurements. This method is based on the application of a heat pulse during a fixed interval of time. The maximum rise in temperature (T m) is monitored by the measurement probe, placed at a certain distance of the heater source. A lowcost high-performance and small temperature sensor (a dynamic V P T AT generator) is required to be placed into the probe which have 0.912 mm in diameter and 20 mm long. If one considers the range of water contents, ratio of water mass to dry soil mass, in a typical agricultural soil (0.05 to 0.35 m 3 m −3), the average sensitivity of the dual probe is about 1.95 • C per unit change (m 3 m −3

This study presents a Multi-Chip-Module-based (MCM) micro-system suited for irrigation control an... more This study presents a Multi-Chip-Module-based (MCM) micro-system suited for irrigation control and management applications. The micro-system includes the soil moisture sensor and an analogue-to-digital converter with signal processing circuitry. The same basic fabrication concepts and materials which made microelectronics successful are now being adapted to making low-cost, small, and high-performance sensor systems with integrated electronics on the same micro-system. Since this sensor has low-cost fabrication for mass production, a network could be implemented in order to achieve an accurate measurement of the soil moisture at the plant root level. A dual-probe heat-pulse technique is used (measurement of the maximum temperature rise at some distance from the heater, after applying a heat-pulse) to determine the volumetric heat capacity and, hence, the water content of the soil. The sensor module is about 30 mm long, 6 mm wide, and 0.8 mm in height; the probe pitch is 3 mm allowing small-scale spatial measurements of soil moisture, which can be made near the soil surface where large root densities are found. The heater uses a nickel-chrome resistor for resistive heating (thermo resistive effect -Joule heat). The temperature sensors (probe and reference) are highaccuracy CMOS smart temperature sensors.

This paper describes a radio frequency transceiver designed in UMC RF 0.18 μm CMOS process. This ... more This paper describes a radio frequency transceiver designed in UMC RF 0.18 μm CMOS process. This process has a poly and six metal layers, allowing the use of integrated spiral inductors (with a reasonable quality factor), high resistor value (a special layer is available) and a ...

The optimization of the thermal co-evaporation process for ntype Bismuth Telluride and p-type Ant... more The optimization of the thermal co-evaporation process for ntype Bismuth Telluride and p-type Antimony Telluride onto plastic substrates (Kapton© polyimide) for thermoelectric applications is reported. Films were co-evaporated from Bismuth and Tellurium or Antimony and Tellurium to obtain Bi 2 Te 3 or Sb 2 Te 3 , respectively. The evaporation rate of each material was monitorized using a crystal oscillator sensor and the power applied to each boat was controlled with a PID algorithm, in order to achieve a precise user-defined constant evaporation rate. The influence of substrate temperature (150-300 ºC) and evaporation rate (2 Å/s-9 Å/s) on the electronic properties of the films was studied and optimized to maximize the thermoelectric figure-of-merit. Energy-dispersive X-ray spectroscopy, X-ray diffraction and Fourier-transform infrared spectroscopy confirmed the formation of Bi 2 Te 3 and Sb 2 Te 3 thin films. Seebeck coefficients (up to 250 µV/ºC), in-plane electrical resistivity (5-40 µΩ.m), Hall mobility (20-100 cm-2 .V-1 .s-1) and carrier concentration (10 19-10 21 cm-3) were measured at room temperature in films fabricated with different process parameters. Thermoelectric p-type and n-type thin films with high figures of merit, suitable for the fabrication of lateral Peltier coolers and thermal micro-generators, were obtained.

Summary: This paper describes the design, modeling and optimization of a miniaturized self-calibr... more Summary: This paper describes the design, modeling and optimization of a miniaturized self-calibrated pyrometer to detect infrared radiation (in 5-20 µm range of wavelengths) in order to measure the real temperature of objects without contact. The microsystem consists of a ...

Induction Motor Slip Control With Efficiency Optimization Using Fuzzy Logic Techniques

This paper describes a fuzzy logic based slip controller for an induction motor, with efficiency ... more This paper describes a fuzzy logic based slip controller for an induction motor, with efficiency optimization for steady state operation. The speed control is accomplished through a Mandani type fuzzy controller, with 11 rules, taking speed error (built with 5 Membership Functions ...

CONFTELE. Conference …, 2005

CMOS technology has reached its maturity. Therefore, design engineers used it for developing RF c... more CMOS technology has reached its maturity. Therefore, design engineers used it for developing RF circuits. The advantages of CMOS technology are the higher integration, low-power consumption, low-voltage supply and low-cost compared with Bipolar technology. The ...

A MCM-Based Microsystem for Soil Moisture Measurements

This work presents a Multi-Chip-Module (MCM) based microsystem for irrigation control in agricult... more This work presents a Multi-Chip-Module (MCM) based microsystem for irrigation control in agriculture. The proposed microsystem includes a soil moisture microsensor, an analog-to-digital converter, signal processing circuits (digital filtering and sensor interface) and a RF ...

International …, 2003

Actuation, monitoring, and control of fabrics feeding during high-speed sewing LF SILVA, M LIMA, ... more Actuation, monitoring, and control of fabrics feeding during high-speed sewing LF SILVA, M LIMA, H CARVALHO, AM ROCHA, FN FERREIRA, JL MONTEIRO, and C COUTO School of Engineering, University of Mmho Guimaraes, Portugal SYNOPSIS For some years now ...

Due the intensive use of power converters and other non-linear loads in industry and by consumers... more Due the intensive use of power converters and other non-linear loads in industry and by consumers in general, it can be observed an increasing deterioration of the power systems voltage and current waveforms. The presence of harmonics in the power lines results in greater power losses ...