Articles de revista
http://hdl.handle.net/2117/3936
2024-03-29T06:24:26Z
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Sensor noise in LISA Pathfinder: laser frequency noise and its coupling to the optical test mass readout
http://hdl.handle.net/2117/405373
Sensor noise in LISA Pathfinder: laser frequency noise and its coupling to the optical test mass readout
Armano, M.; Audley, H.; Baird, J.; Binetruy, P.; Wollborn, Michael; Bortoluzzi, D.; Brandt, N.; Castelli, Eleonora; Cavalleri, A.; Cesarini, A.; Cruise, M.; Danzmann, K.; de Deus Silva, Marcus; Ramos Castro, Juan José
The LISA Pathfinder (LPF) mission successfully demonstrated the feasibility of the technology needed for the future space borne gravitational wave observatory LISA. A key subsystem under study was the laser interferometer, which measured the changes in relative distance in between two test masses (TMs). It achieved a sensitivity of 32.0 + 2.4 - 1.7 ¿ ¿ fm / v Hz , which was significantly better than the prelaunch tests. This improved performance allowed direct observation of the influence of laser frequency noise in the readout. The differences in optical path lengths between the measurement and reference beams in the individual interferometers of our setup determined the level of this undesired readout noise. Here, we discuss the dedicated experiments performed on LPF to measure these differences with high precision. We reached differences in path length difference between ( 368 ± 5 ) ¿ ¿ µm and ( 329.6 ± 0.9 ) ¿ ¿ µm which are significantly below the required level of 1 mm or 1000 ¿ ¿ µm . These results are an important contribution to our understanding of the overall sensor performance. Moreover, we observed varying levels of laser frequency noise over the course of the mission. We provide evidence that these do not originate from the laser frequency stabilization scheme which worked as expected. Therefore, this frequency stabilization would be applicable to other missions with similar laser frequency stability requirements.
2024-03-26T12:55:34Z
Armano, M.
Audley, H.
Baird, J.
Binetruy, P.
Wollborn, Michael
Bortoluzzi, D.
Brandt, N.
Castelli, Eleonora
Cavalleri, A.
Cesarini, A.
Cruise, M.
Danzmann, K.
de Deus Silva, Marcus
Ramos Castro, Juan José
The LISA Pathfinder (LPF) mission successfully demonstrated the feasibility of the technology needed for the future space borne gravitational wave observatory LISA. A key subsystem under study was the laser interferometer, which measured the changes in relative distance in between two test masses (TMs). It achieved a sensitivity of 32.0 + 2.4 - 1.7 ¿ ¿ fm / v Hz , which was significantly better than the prelaunch tests. This improved performance allowed direct observation of the influence of laser frequency noise in the readout. The differences in optical path lengths between the measurement and reference beams in the individual interferometers of our setup determined the level of this undesired readout noise. Here, we discuss the dedicated experiments performed on LPF to measure these differences with high precision. We reached differences in path length difference between ( 368 ± 5 ) ¿ ¿ µm and ( 329.6 ± 0.9 ) ¿ ¿ µm which are significantly below the required level of 1 mm or 1000 ¿ ¿ µm . These results are an important contribution to our understanding of the overall sensor performance. Moreover, we observed varying levels of laser frequency noise over the course of the mission. We provide evidence that these do not originate from the laser frequency stabilization scheme which worked as expected. Therefore, this frequency stabilization would be applicable to other missions with similar laser frequency stability requirements.
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Confronting positions: para-vs. meta-functionalization in triindole for p-type air-stable OTFTs
http://hdl.handle.net/2117/405368
Confronting positions: para-vs. meta-functionalization in triindole for p-type air-stable OTFTs
Cuadrado Santolaria, Alba; Bujaldón Carbó, Roger; Fabregat Pallejà, Clara; Puigdollers i González, Joaquim; Velasco Castrillo, Maria Dolores
The 5,10,15-trihexyl-10,15-dihydro-5H-diindolo[3,2-a:3',2'-c]carbazole core, namely triindole, is well-known for its prominent hole-transporting properties and air stability. The functionalization of this core is also rather versatile, which allows the modulation of its properties by anchoring targeted scaffolds to different positions, e.g. 3,8,13 (para with respect to the nitrogens), 2,7,12 (analogously meta) or the nitrogen heteroatoms. Therefore, triindole excels as a pivotal semiconductor to be exploited in long-lasting organic thin-film transistors (OTFTs). This report aims to shed light on the effect of functionalizing whether para or meta positions with sulfurated moieties, in the pursuit of an enhanced performance in OTFTs. Remarkably, meta-substituted derivatives outshone their para- counterparts in terms of thermal, optical, intermolecular arrangement and semiconductor properties, claiming mobility values up to 2 × 10-3 cm2 V-1 s-1 and a shelf lifetime beyond the analyzed period of 5 months. Analysis of the thin films by grazing incidence X-ray diffraction (GIRXD) and atomic force microscopy (AFM) revealed that the meta-substitution also induces a higher degree of order and better morphology, further corroborating the potential of this structural approach.
2024-03-26T12:07:00Z
Cuadrado Santolaria, Alba
Bujaldón Carbó, Roger
Fabregat Pallejà, Clara
Puigdollers i González, Joaquim
Velasco Castrillo, Maria Dolores
The 5,10,15-trihexyl-10,15-dihydro-5H-diindolo[3,2-a:3',2'-c]carbazole core, namely triindole, is well-known for its prominent hole-transporting properties and air stability. The functionalization of this core is also rather versatile, which allows the modulation of its properties by anchoring targeted scaffolds to different positions, e.g. 3,8,13 (para with respect to the nitrogens), 2,7,12 (analogously meta) or the nitrogen heteroatoms. Therefore, triindole excels as a pivotal semiconductor to be exploited in long-lasting organic thin-film transistors (OTFTs). This report aims to shed light on the effect of functionalizing whether para or meta positions with sulfurated moieties, in the pursuit of an enhanced performance in OTFTs. Remarkably, meta-substituted derivatives outshone their para- counterparts in terms of thermal, optical, intermolecular arrangement and semiconductor properties, claiming mobility values up to 2 × 10-3 cm2 V-1 s-1 and a shelf lifetime beyond the analyzed period of 5 months. Analysis of the thin films by grazing incidence X-ray diffraction (GIRXD) and atomic force microscopy (AFM) revealed that the meta-substitution also induces a higher degree of order and better morphology, further corroborating the potential of this structural approach.
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Toward noninvasive monitoring of plant leaf water content by electrical impedance spectroscopy
http://hdl.handle.net/2117/405148
Toward noninvasive monitoring of plant leaf water content by electrical impedance spectroscopy
Serrano Finetti, Roberto Ernesto; Castillo Ruiz, Oscar Eduardo; Alejos Lipa, Smith Salomon; León Hilario, Ludwin Misael
Plant water content is one key factor that affects the wellbeing of plants. Furthermore, detecting plant water needs in a timely manner is important when considering irrigation strategies (water management). A first step toward plant water monitoring is the availability of a portable and cost-effective system that yields reliable information. Electrical impedance spectroscopy (EIS) has previously been used invasively to provide such data and can be implemented at an acceptable cost. In this work, a cost-effective impedance analyzer capable of performing noninvasive four-electrode measurements was built. In addition, data fitting has been improved by using a modified equivalent circuit model, yielding relevant information about the plant water status. The results show that the resistor that models the extracellular fluid can track the change in the water content of a plant leaf while it is drying at room temperature. On the other hand, impedance data might provide information about the leaf tissue structure at small interelectrode distances.
2024-03-22T11:15:08Z
Serrano Finetti, Roberto Ernesto
Castillo Ruiz, Oscar Eduardo
Alejos Lipa, Smith Salomon
León Hilario, Ludwin Misael
Plant water content is one key factor that affects the wellbeing of plants. Furthermore, detecting plant water needs in a timely manner is important when considering irrigation strategies (water management). A first step toward plant water monitoring is the availability of a portable and cost-effective system that yields reliable information. Electrical impedance spectroscopy (EIS) has previously been used invasively to provide such data and can be implemented at an acceptable cost. In this work, a cost-effective impedance analyzer capable of performing noninvasive four-electrode measurements was built. In addition, data fitting has been improved by using a modified equivalent circuit model, yielding relevant information about the plant water status. The results show that the resistor that models the extracellular fluid can track the change in the water content of a plant leaf while it is drying at room temperature. On the other hand, impedance data might provide information about the leaf tissue structure at small interelectrode distances.
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Textile antenna sensor in SIW technology for liquid characterization
http://hdl.handle.net/2117/405095
Textile antenna sensor in SIW technology for liquid characterization
El Gharbi, Mariam; Bozzi, M.; Fernández García, Raúl; Gil Galí, Ignacio
This study showcases the creation of an innovative textile antenna sensor that utilizes a resonant cavity for the purpose of liquid characterization. The cavity is based on circular substrate integrated waveguide (SIW) technology. A hole is created in the middle of the structure where a pipe is used to inject the liquid under test. The pipe is covered by a metal sheath to enhance the electromagnetic field’s penetration of the tube, thus increasing the device’s sensitivity. The resonance frequency of the proposed system is altered when the liquid under test is inserted into the sensitive area of the structure. The sensing of the liquid is achieved by the measurement of its dielectric properties via the perturbation of the electric fields in the SIW configuration. The S11 measurement enables the extraction of the electromagnetic properties of the liquid injected into the pipe. Specifically, the dielectric constant of the liquid is determined by observing the resonance frequency shift relative to that of an air-filled pipe. The loss tangent of the liquid is extracted by comparing the variation in the quality factor with that of an air-filled pipe after eliminating the inherent losses of the structure. The proposed SIW antenna sensor demonstrates a high sensitivity of 0.7 GHz/¿er corresponding to a dielectric constant range from 4 to 72. To the best of our knowledge, this article presents for the first time the ability of a fully textile SIW cavity antenna-based sensor to characterize the dielectric properties of a liquid under test and emphasizes its differentiating features compared to PCB-based designs. The unique attributes of the textile-based antenna stem from its flexibility, conformability, and compatibility with various liquids.
2024-03-21T13:49:50Z
El Gharbi, Mariam
Bozzi, M.
Fernández García, Raúl
Gil Galí, Ignacio
This study showcases the creation of an innovative textile antenna sensor that utilizes a resonant cavity for the purpose of liquid characterization. The cavity is based on circular substrate integrated waveguide (SIW) technology. A hole is created in the middle of the structure where a pipe is used to inject the liquid under test. The pipe is covered by a metal sheath to enhance the electromagnetic field’s penetration of the tube, thus increasing the device’s sensitivity. The resonance frequency of the proposed system is altered when the liquid under test is inserted into the sensitive area of the structure. The sensing of the liquid is achieved by the measurement of its dielectric properties via the perturbation of the electric fields in the SIW configuration. The S11 measurement enables the extraction of the electromagnetic properties of the liquid injected into the pipe. Specifically, the dielectric constant of the liquid is determined by observing the resonance frequency shift relative to that of an air-filled pipe. The loss tangent of the liquid is extracted by comparing the variation in the quality factor with that of an air-filled pipe after eliminating the inherent losses of the structure. The proposed SIW antenna sensor demonstrates a high sensitivity of 0.7 GHz/¿er corresponding to a dielectric constant range from 4 to 72. To the best of our knowledge, this article presents for the first time the ability of a fully textile SIW cavity antenna-based sensor to characterize the dielectric properties of a liquid under test and emphasizes its differentiating features compared to PCB-based designs. The unique attributes of the textile-based antenna stem from its flexibility, conformability, and compatibility with various liquids.
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CMOS wireless hybrid transceiver powered by integrated photodiodes for ultra-low-power IoT applications
http://hdl.handle.net/2117/405041
CMOS wireless hybrid transceiver powered by integrated photodiodes for ultra-low-power IoT applications
Nikseresht, Sasan; Fernández, Daniel; Cosp Vilella, Jordi; Selin Lorenzo, Irina; Madrenas Boadas, Jordi
In this article, a communication platform for a self-powered integrated light energy harvester based on a wireless hybrid transceiver is proposed. It consists of an optical receiver and a reconfigurable radio frequency (RF) transmitter. The hybrid optical/RF communication approach improves load balancing, energy efficiency, security, and interference reduction. A light beam for communication in the downlink, coupled with a 1 MHz radio frequency signal for the uplink, offers a small area and ultra-low-power consumption design for Smart Dust/IoT applications. The optical receiver employs a new charge-pump-based technique for the automatic acquisition of a reference voltage, enabling compensation for comparator offset errors and variations in DC-level illumination. On the uplink side, the reconfigurable transmitter supports OOK/FSK/BPSK data modulation. Electronic components and the energy harvester, including integrated photodiodes, have been designed, fabricated, and experimentally tested in a 0.18 µm triple-well CMOS technology in a 1.5 × 1.3 mm2 chip area. Experiments show the correct system behavior for general and pseudo-random stream input data, with a minimum pulse width of 50 µs and a data transmission rate of 20 kb/s for the optical receiver and 1 MHz carrier frequency. The maximum measured power of the signal received from the transmitter is approximately -18.65 dBm when using a light-harvested power supply.
2024-03-20T15:41:03Z
Nikseresht, Sasan
Fernández, Daniel
Cosp Vilella, Jordi
Selin Lorenzo, Irina
Madrenas Boadas, Jordi
In this article, a communication platform for a self-powered integrated light energy harvester based on a wireless hybrid transceiver is proposed. It consists of an optical receiver and a reconfigurable radio frequency (RF) transmitter. The hybrid optical/RF communication approach improves load balancing, energy efficiency, security, and interference reduction. A light beam for communication in the downlink, coupled with a 1 MHz radio frequency signal for the uplink, offers a small area and ultra-low-power consumption design for Smart Dust/IoT applications. The optical receiver employs a new charge-pump-based technique for the automatic acquisition of a reference voltage, enabling compensation for comparator offset errors and variations in DC-level illumination. On the uplink side, the reconfigurable transmitter supports OOK/FSK/BPSK data modulation. Electronic components and the energy harvester, including integrated photodiodes, have been designed, fabricated, and experimentally tested in a 0.18 µm triple-well CMOS technology in a 1.5 × 1.3 mm2 chip area. Experiments show the correct system behavior for general and pseudo-random stream input data, with a minimum pulse width of 50 µs and a data transmission rate of 20 kb/s for the optical receiver and 1 MHz carrier frequency. The maximum measured power of the signal received from the transmitter is approximately -18.65 dBm when using a light-harvested power supply.
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A front-end circuit for two-wire connected resistive sensors with a wire-resistance compensation
http://hdl.handle.net/2117/404937
A front-end circuit for two-wire connected resistive sensors with a wire-resistance compensation
Reverter Cubarsí, Ferran
In this article, a novel front-end circuit for remote two-wire resistive sensors that is insensitive to the wire resistances is proposed and experimentally characterized. The circuit relies on an OpAmp-based current source with a square-wave excitation, two twin diodes in the feedback path, and a low-pass filter at the output. Using such a circuit topology, the output is a DC voltage proportional to the sensor resistance and independent of the wire resistances. A prototype was built measuring resistances that correspond to a Pt100 thermal sensor and with different values of wire resistance. The experimental results show that the output voltage is almost insensitive to both the wire resistances and their mismatch, with a relative error (with respect to the case with null parasitic resistance) in the range of 0.01–0.03% Full-Scale Span (FSS). In addition, the proposed circuit shows a remarkable linearity (around 0.01% FSS), and again this is independent of the presence and also of the mismatch of the wire resistances.
2024-03-19T12:58:23Z
Reverter Cubarsí, Ferran
In this article, a novel front-end circuit for remote two-wire resistive sensors that is insensitive to the wire resistances is proposed and experimentally characterized. The circuit relies on an OpAmp-based current source with a square-wave excitation, two twin diodes in the feedback path, and a low-pass filter at the output. Using such a circuit topology, the output is a DC voltage proportional to the sensor resistance and independent of the wire resistances. A prototype was built measuring resistances that correspond to a Pt100 thermal sensor and with different values of wire resistance. The experimental results show that the output voltage is almost insensitive to both the wire resistances and their mismatch, with a relative error (with respect to the case with null parasitic resistance) in the range of 0.01–0.03% Full-Scale Span (FSS). In addition, the proposed circuit shows a remarkable linearity (around 0.01% FSS), and again this is independent of the presence and also of the mismatch of the wire resistances.
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Voltage support provided by three-phase three-wire inverters with independent reactive phase-current injection
http://hdl.handle.net/2117/404742
Voltage support provided by three-phase three-wire inverters with independent reactive phase-current injection
Iñiguez Amigot, José Ignacio; Duarte Mejia, Josue Neftali; Camacho Santiago, Antonio; Miret Tomàs, Jaume; Castilla Fernández, Miguel
During voltage sags, three-phase three-wire power inverters can provide voltage support with several current injection strategies. In general, good results are ob- tained, except in overvoltage situations when one or more phase voltages exceed the allowed limit in grid codes. In three-wire inverters, this is a challenging problem because phase voltages are coupled. In this article, we present a strategy that performs independent reactive current injec- tion for each phase, which solves the overvoltage problem. This approach also includes a current-limiting technique that guarantees the injection of the maximum active power under safe current conditions. A stability analysis is carried out based on the small-gain theorem. The properties of the proposed control are experimentally validated with selected tests in a laboratory setup. A performance comparison with state-of-the-art control strategies is also included in the experimental validation.
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2024-03-15T14:02:34Z
Iñiguez Amigot, José Ignacio
Duarte Mejia, Josue Neftali
Camacho Santiago, Antonio
Miret Tomàs, Jaume
Castilla Fernández, Miguel
During voltage sags, three-phase three-wire power inverters can provide voltage support with several current injection strategies. In general, good results are ob- tained, except in overvoltage situations when one or more phase voltages exceed the allowed limit in grid codes. In three-wire inverters, this is a challenging problem because phase voltages are coupled. In this article, we present a strategy that performs independent reactive current injec- tion for each phase, which solves the overvoltage problem. This approach also includes a current-limiting technique that guarantees the injection of the maximum active power under safe current conditions. A stability analysis is carried out based on the small-gain theorem. The properties of the proposed control are experimentally validated with selected tests in a laboratory setup. A performance comparison with state-of-the-art control strategies is also included in the experimental validation.
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Highly reflective and passivated ohmic contacts in p-Ge by laser processing of aSiCx:H(i)/Al2O3/aSiC films for thermophotovoltaic applications
http://hdl.handle.net/2117/404633
Highly reflective and passivated ohmic contacts in p-Ge by laser processing of aSiCx:H(i)/Al2O3/aSiC films for thermophotovoltaic applications
Gamel, Mansur Mohammed Ali; López Rodríguez, Gema; Medrano Gómez, Álvaro Manuel; Jiménez Rodríguez, Alba María; Datas Medina, Alejandro; Garin Escriva, Moises; Martín García, Isidro
Crystalline germanium (c-Ge) has historically been regarded as a cost-effective alternative to III-V semiconductors for thermophotovoltaic (TPV) device fabrication. However, Ge-based devices have not yet reported high efficiencies, partially due to the lack of an efficient back-surface reflector that turns back to the heat source out-band (sub-bandgap) thermal radiation. The difficulty of implementing back surface reflectors in Ge TPV cells is related to the simultaneous requirement of good back surface passivation, low electrical resistivity, and high out-band optical reflectivity. In this study, we demonstrate a highly reflective ohmic contact to p-type c-Ge (doping concentration of 2 × 1015 cm-3) made of an aSiCx(1 nm)/Al2O3 (50 nm)/aSiC (45 nm) stack that is laser processed using Nd:YVO4 laser emitting at 355 nm to create punctual p+ contacts (locally diffused Al regions). This stack is finally caped with a thick (1000 nm) Al layer that behaves as a metallic mirror and back electrode. As the laser processed area increases from 0.1 to 3 %, which is the typical range in the final devices, the surface recombination velocity increase from 10.5 to 60.0 cm/s, while the effective contact resistance reduces from 0.462 to 0.036 O cm2. Moreover, a sub-bandgap reflectance of 90–98 % is achieved. Simulations assuming ideal device configuration indicate that implementing these back contacts could potentially enable TPV cell conversion efficiencies comparable to the reported high-efficiency c-Ge TPV cells operating at similar illumination temperature.
2024-03-14T15:01:30Z
Gamel, Mansur Mohammed Ali
López Rodríguez, Gema
Medrano Gómez, Álvaro Manuel
Jiménez Rodríguez, Alba María
Datas Medina, Alejandro
Garin Escriva, Moises
Martín García, Isidro
Crystalline germanium (c-Ge) has historically been regarded as a cost-effective alternative to III-V semiconductors for thermophotovoltaic (TPV) device fabrication. However, Ge-based devices have not yet reported high efficiencies, partially due to the lack of an efficient back-surface reflector that turns back to the heat source out-band (sub-bandgap) thermal radiation. The difficulty of implementing back surface reflectors in Ge TPV cells is related to the simultaneous requirement of good back surface passivation, low electrical resistivity, and high out-band optical reflectivity. In this study, we demonstrate a highly reflective ohmic contact to p-type c-Ge (doping concentration of 2 × 1015 cm-3) made of an aSiCx(1 nm)/Al2O3 (50 nm)/aSiC (45 nm) stack that is laser processed using Nd:YVO4 laser emitting at 355 nm to create punctual p+ contacts (locally diffused Al regions). This stack is finally caped with a thick (1000 nm) Al layer that behaves as a metallic mirror and back electrode. As the laser processed area increases from 0.1 to 3 %, which is the typical range in the final devices, the surface recombination velocity increase from 10.5 to 60.0 cm/s, while the effective contact resistance reduces from 0.462 to 0.036 O cm2. Moreover, a sub-bandgap reflectance of 90–98 % is achieved. Simulations assuming ideal device configuration indicate that implementing these back contacts could potentially enable TPV cell conversion efficiencies comparable to the reported high-efficiency c-Ge TPV cells operating at similar illumination temperature.
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Impact of atomic layer deposition temperature on electrical and optical properties of ZnO:Al films
http://hdl.handle.net/2117/404515
Impact of atomic layer deposition temperature on electrical and optical properties of ZnO:Al films
Masmitjà Rusiñol, Gerard; Estarlich Gil, Pau; López Rodríguez, Gema; Martín García, Isidro; Voz Sánchez, Cristóbal; Placidi, Marcel Jose; Torrens Dinarès, Arnau; Saucedo Silva, Edgardo Ademar; Vasquez, Pia; Muñoz, Delfina; Puigdollers i González, Joaquim; Ortega Villasclaras, Pablo Rafael
This work highlights the impact of growth temperature on electrical and optical properties of Al-doped ZnO (AZO) films deposited by atomic layer deposition (ALD) technique. The ALD process and super-cycle sequence have been optimized, identifying their influence on film resistivity. By using this optimum ALD procedure, the optical and electrical properties of AZO films have been widely analyzed considering the deposition temperature. Results show promising values with film resistivity in the range of 1 m¿cm and average optical absorption below 2% for 50 nm thick AZO layers. Hall effect, X-ray diffraction and ellipsometry measurements point out that these excellent values are related to their high carrier concentration and mobility, crystalline phase and optical band gap resulting in ALD AZO films with very good properties to be applied in photovoltaic devices as transparent conductive oxide electrode
2024-03-14T11:18:26Z
Masmitjà Rusiñol, Gerard
Estarlich Gil, Pau
López Rodríguez, Gema
Martín García, Isidro
Voz Sánchez, Cristóbal
Placidi, Marcel Jose
Torrens Dinarès, Arnau
Saucedo Silva, Edgardo Ademar
Vasquez, Pia
Muñoz, Delfina
Puigdollers i González, Joaquim
Ortega Villasclaras, Pablo Rafael
This work highlights the impact of growth temperature on electrical and optical properties of Al-doped ZnO (AZO) films deposited by atomic layer deposition (ALD) technique. The ALD process and super-cycle sequence have been optimized, identifying their influence on film resistivity. By using this optimum ALD procedure, the optical and electrical properties of AZO films have been widely analyzed considering the deposition temperature. Results show promising values with film resistivity in the range of 1 m¿cm and average optical absorption below 2% for 50 nm thick AZO layers. Hall effect, X-ray diffraction and ellipsometry measurements point out that these excellent values are related to their high carrier concentration and mobility, crystalline phase and optical band gap resulting in ALD AZO films with very good properties to be applied in photovoltaic devices as transparent conductive oxide electrode
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Variations of the Gauss Seidel and the gauss implicit z-bus load flow methods for primary-secondary integrated distribution grids
http://hdl.handle.net/2117/403971
Variations of the Gauss Seidel and the gauss implicit z-bus load flow methods for primary-secondary integrated distribution grids
Barrenechea Gruber, Roberto Carlos; García de Vicuña Muñoz de la Nava, José Luis; Castilla Fernández, Miguel; Rypin, Federico; Paiva Mata, Pedro
The primary and secondary distribution grids are typically designed separately and operated with a radial configuration; therefore, specialized load flow methods only applicable to radial or weakly meshed networks are normally used. However, projections indicate that the distribution grids will be more interconnected in the future, mainly because of the inclusion of distributed generation, voltage and reliability optimization, as well as an efficiency improvement when the primary and secondary networks are considered in an integrated way. For this new meshed grids scenario, the efficient and precise typically used load flow methods for distribution networks are no longer applicable and it becomes necessary using load flow algorithms that are also applicable for meshed configurations, such as the ones classically used for transmission networks like the Newton-Raphson, Gauss-Seidel and Gauss Implicit Z-bus methods, while also procuring to avoid potential singularity problems which may arise when dealing with long radial grids. In this work, variations of the Gauss-Seidel and Gauss Implicit Z-bus methods are presented, that are adequate for low and medium voltage grids regardless of the network configuration. Additionally, a linear, direct, and non-iterative load flow variation is presented as well as a comparison between different possible convergence criteria for the classical methods.
2024-03-08T09:20:23Z
Barrenechea Gruber, Roberto Carlos
García de Vicuña Muñoz de la Nava, José Luis
Castilla Fernández, Miguel
Rypin, Federico
Paiva Mata, Pedro
The primary and secondary distribution grids are typically designed separately and operated with a radial configuration; therefore, specialized load flow methods only applicable to radial or weakly meshed networks are normally used. However, projections indicate that the distribution grids will be more interconnected in the future, mainly because of the inclusion of distributed generation, voltage and reliability optimization, as well as an efficiency improvement when the primary and secondary networks are considered in an integrated way. For this new meshed grids scenario, the efficient and precise typically used load flow methods for distribution networks are no longer applicable and it becomes necessary using load flow algorithms that are also applicable for meshed configurations, such as the ones classically used for transmission networks like the Newton-Raphson, Gauss-Seidel and Gauss Implicit Z-bus methods, while also procuring to avoid potential singularity problems which may arise when dealing with long radial grids. In this work, variations of the Gauss-Seidel and Gauss Implicit Z-bus methods are presented, that are adequate for low and medium voltage grids regardless of the network configuration. Additionally, a linear, direct, and non-iterative load flow variation is presented as well as a comparison between different possible convergence criteria for the classical methods.