Complete and versatile remote controller for PV systems

The promotion of the distributed generation and the photovoltaic (PV) energy great potential put this technology in the spotlight of investors. Thus, the optimization of its efficiency is made a priority. In this paper, a complete and versatile remote controller (C&VRC) for PV systems is presented, scalable to any kind and size of installations (with or without partial shading, with or without connection to the grid, housing, small plants or even large-scale solar plants) and valid for any weather conditions. The C&VRC involves the controller itself, which is constituted by a set of sensors and actuators connected to the converters Direct Current (DC)/DC and DC/Alternating Current (AC), if necessary, and a control unit communicated with them through the third-generation mobile telecommunications technology (3G) network. The control strategies can be changed according to the different weather conditions and installations characteristics, which guaranties the optimum performance of the system. The use of the 3G network as communication platform makes the C&VRC useful in remote and low accessibility places, because it is the most extended worldwide. The C&VRC is also based on free software, open hardware and low-cost electronic devices. Experimental results are presented in this paper to show the C&VRC optimum usability.This paper is framed in the project “Integral control system to optimize the microgrids energy demand” funded by the Spanish Ministry of Science and Innovation, call for Scientific and Technical Research and Innovation 2020-2023. Funding for open access charge: Universidad de Huelva / CBUA.This paper is framed in the project “Integral control system to optimize the microgrids energy demand” funded by the Spanish Ministry of Science and Innovation, call for Scientific and Technical Research and Innovation 2020-2023. Funding for open access charge: Universidad de Huelva / CBUA

Usefulness of bone turnover markers as predictors of mortality risk, disease progression and skeletal-related events appearance in patients with prostate cancer with bone metastases following treatment with zoledronic acid: TUGAMO study

Owing to the limited validity of clinical data on the treatment of prostate cancer (PCa) and bone metastases, biochemical markers are a promising tool for predicting survival, disease progression and skeletal-related events (SREs) in these patients. The aim of this study was to evaluate the predictive capacity of biochemical markers of bone turnover for mortality risk, disease progression and SREs in patients with PCa and bone metastases undergoing treatment with zoledronic acid (ZA). Methods: This was an observational, prospective and multicenter study in which ninety-eight patients were included. Patients were treated with ZA (4mg every 4 weeks for 18 months). Data were collected at baseline and 3, 6, 9, 12, 15 and 18 months after the beginning of treatment. Serum levels of bone alkaline phosphtase (BALP), aminoterminal propeptide of procollagen type I (P1NP) and beta-isomer of carboxiterminal telopeptide of collagen I (b-CTX) were analysed at all points in the study. Data on disease progression, SREs development and survival were recorded. Results: Cox regression models with clinical data and bone markers showed that the levels of the three markers studied were predictive of survival time, with b-CTX being especially powerful, in which a lack of normalisation in visit 1 (3 months after the beginning of treatment) showed a 6.3-times more risk for death than in normalised patients. Levels of these markers were also predictive for SREs, although in this case BALP and P1NP proved to be better predictors. We did not find any relationship between bone markers and disease progression. Conclusion: In patients with PCa and bone metastases treated with ZA, b-CTX and P1NP can be considered suitable predictors for mortality risk, while BALP and P1NP are appropriate for SREs. The levels of these biomarkers 3 months after the beginning of treatment are especially importantThis study was supported by Novartis Oncology Spai

Effectiveness of an intervention for improving drug prescription in primary care patients with multimorbidity and polypharmacy:Study protocol of a cluster randomized clinical trial (Multi-PAP project)

This study was funded by the Fondo de Investigaciones Sanitarias ISCIII (Grant Numbers PI15/00276, PI15/00572, PI15/00996), REDISSEC (Project Numbers RD12/0001/0012, RD16/0001/0005), and the European Regional Development Fund ("A way to build Europe").Background: Multimorbidity is associated with negative effects both on people's health and on healthcare systems. A key problem linked to multimorbidity is polypharmacy, which in turn is associated with increased risk of partly preventable adverse effects, including mortality. The Ariadne principles describe a model of care based on a thorough assessment of diseases, treatments (and potential interactions), clinical status, context and preferences of patients with multimorbidity, with the aim of prioritizing and sharing realistic treatment goals that guide an individualized management. The aim of this study is to evaluate the effectiveness of a complex intervention that implements the Ariadne principles in a population of young-old patients with multimorbidity and polypharmacy. The intervention seeks to improve the appropriateness of prescribing in primary care (PC), as measured by the medication appropriateness index (MAI) score at 6 and 12months, as compared with usual care. Methods/Design: Design:pragmatic cluster randomized clinical trial. Unit of randomization: family physician (FP). Unit of analysis: patient. Scope: PC health centres in three autonomous communities: Aragon, Madrid, and Andalusia (Spain). Population: patients aged 65-74years with multimorbidity (≥3 chronic diseases) and polypharmacy (≥5 drugs prescribed in ≥3months). Sample size: n=400 (200 per study arm). Intervention: complex intervention based on the implementation of the Ariadne principles with two components: (1) FP training and (2) FP-patient interview. Outcomes: MAI score, health services use, quality of life (Euroqol 5D-5L), pharmacotherapy and adherence to treatment (Morisky-Green, Haynes-Sackett), and clinical and socio-demographic variables. Statistical analysis: primary outcome is the difference in MAI score between T0 and T1 and corresponding 95% confidence interval. Adjustment for confounding factors will be performed by multilevel analysis. All analyses will be carried out in accordance with the intention-to-treat principle. Discussion: It is essential to provide evidence concerning interventions on PC patients with polypharmacy and multimorbidity, conducted in the context of routine clinical practice, and involving young-old patients with significant potential for preventing negative health outcomes. Trial registration: Clinicaltrials.gov, NCT02866799Publisher PDFPeer reviewe

Elaboración de píldoras educativas sobre Historia de la Veterinaria

Tras el éxito de la utilización de la ludificación como motivación para el estudio de la Historia de la Veterinaria, nos propusimos crear pequeños vídeos o píldoras de conocimiento sobre hechos o personajes históricos que fueran reusables (se pueden utilizar en diferentes contextos), interoperables (sirven para propósitos diferentes) y accesibles por su formato digital que facilita el almacenaje y su recuperación. En este proyecto se ha grabado más escenas antes del confinamiento y preparados la historioteca con una de las píldoras ya definitivas

Design of a non-linear contro ller to track de maximum power point of photovoltaic systems in electrical power systems with distributed generation

This Doctoral thesis work is focused on the non-linear backstepping control of a buck-boost power converter and DC/AC power converter to track the maximum power point in PV systems and transfer the power to the electrical network. First, a backstepping control has been implemented to regulate the PV array output voltage in simulation to achieve the maximum power point. Forthat, a grid-connected PV system that consists of a PV array, a buck-boost converter, a DC/AC converter and a load has been modeled in Matlab-Simulink. Then, the designed backstepping controller is implemented in the system. The backstepping control is based on Lyapunov functions guaranteeing the locally stability of the system. This control is robust and tests have been carried out to validate its performance. Once the proposed control is verified in simulation, the method has been proved in an experimental platform. In this case, the experimental platform consists of a commercial PV module, a built buck-boost converter and a DC load to test the backstepping controller in the DC/DC converter. The experiments carried out validate the performance of the proposed control. The voltage that provides the maximum power point is always achieved under changeable environmental conditions, testing the robustness of the control. Finally, the non-linear backstepping controller is proposed to control the DC/AC power converter in an experimental platform, including the connection to the grid. Thus, backstepping controllers are obtained for distributed hybrid photovoltaic (PV) power supplies of telecommunication equipment. The grid-connected PV system contains the PV array, the built DC-DC buck-boost converters linked to single-phase inverters and telecom equipment as loads. The backstepping approach is robust and able to cope with the grid non-linearity and uncertainties, providing DC input current and voltage controllers for the buck-boost converter to track the PV panel maximum power point, regulating the PV output DC voltage to extract maximum power; unity power factor sinusoidal AC smart-grid inverter currents and constant DC link voltages suited for telecom equipment; and inverter bidirectional power transfer. Experimental results are obtained from a lab set-up controlled by one low- cost dsPIC. Results show the controllers guarantee maximum power transfer to the telecom equipment/AC grid, ensuring steady DC link voltage while absorbing/injecting low harmonic distortion current into the smart-grid. A modification of the backstepping control has been also proposed, an adaptive backstepping controller. This non-linear control also tracks the maximum power point regulating the buck-boost converter input voltage regardless of the parameter values of the DC/DC converter. Apart from the proposed algorithms, other MPPT algorithms have been implemented in order to compare the results of different techniques. A neuro-fuzzy system with fuzzy logic MPPT control is designed and then it is compared with the P&O algorithm, the PI control and the proposed backstepping control. Finally, the research work about the PV system control under partial shading conditions using artificial vision with backstepping control is sent to a paper, being in revision at this moment. Additional system performance related with power quality has been proposed. A PV active power line conditioner is designed to transfer the maximum power to the electrical network and to compensate the reactive power and the non-linear loads. Besides, the use of switching output reactances is proposed to improve the compensation of a shunt active power filter. Finally, two power indexes have been tested in a distributed network, the Load Characterization Index (LCI) that identifies linear and non-linear loads in the power systems and the Unbalance Current Ratio (UCR) that assigns the responsibility for system unbalance to load and source sides.Esta tesis doctoral se centra en el diseño de un control no lineal backstepping para controlar un convertidor buck-boost y un inversor para realizar el seguimiento del punto de máxima potencia (MPP) en sistemas FV y transferir potencia a la red. Se ha implementado un controlador backstepping para regular la tensión de salida de un array FV en simulación para conseguir el MPP. Se ha simulado en Matlab-Simulink un sistema FV conectado a red que está formado por un array FV, un convertidor buck-boost, un inversor y una carga. El controlador diseñado ha sido implementado también. Este control está basado en el uso de funciones de Lyapunov para garantizar la estabilidad local del sistema. El control backstepping es robusto y los experimentos llevados a cabo validan su funcionamiento. Una vez verificado el control en simulación, el método ha sido validado en una plataforma experimental. La plataforma experimental desarrollada está compuesta por un módulo FV comercial, un convertidor buck-boost construido y una carga para comprobar el funcionamiento del backstepping en el convertidor DC/DC. Los experimentos llevados a cabo validan la eficiencia del control propuesto. La tensión que suministra el punto de máxima potencia se alcanza siempre incluso con condiciones ambientales cambiantes, comprobando así la robustez del control. Finalmente, se ha propuesto el diseño de un controlador backstepping para controlar el convertidor DC/AC en una plataforma experimental incluyendo la conexión a red. Los controladores backstepping suministran potencia FV en distribuciones híbridas para equipos de telecomunicación. El sistema FV conectado a red contiene un array FV, el buck-boost construido, inversores monofásicos y equipos de telecomunicaciones como cargas. El método backstepping es robusto y capaz de enfrentarse a las no linealidades e incertidumbres de la red eléctrica, suministrando los controladores la tensión e intensidad DC requerida para que el buck-boost siga el MPP del array FV, regulando la tensión de salida de los módulos para extraer la máxima potencia. Además, los controladores consiguen que las intensidades AC del inversor sean sinusoidales con factor de potencia unitario y una tensión de entrada al inversor constante apropiada para el suministro de equipos de telecomunicaciones. Este control logra que la transferencia de potencia por el convertidor DC/AC sea bidireccional, puestrabaja como inversor o como rectificador. Los resultados experimentales se han logrado implementando los controladores en un microcontroladorlow-cost. Los resultados muestran que el control garantiza la máxima transferencia de potencia al equipo de telecomunicación o a la red eléctrica, asegurando una tensión constante a la entrada del inversor mientras que absorbe o inyecta una intensidad con baja distorsión armónica a la smart-grid. Como trabajo adicional, se ha propuesto un control backstepping adaptativo. El control también sigue el MPP, regulando la tensión de entrada del convertidor buck-boost sin importar los valores de los parámetros del convertidor. Otros algoritmos MPPT se han usado. Un sistema neuro-fuzzy con un control difuso se ha diseñado para compararlo con el P&O, con el control PI y con el control backsteppingpropuesto. Se ha propuesto un control basado en visión artificial con backstepping para detectar sombras para los sistemas FV con sombreado parcial. Se han propuesto otras prestaciones relacionadas con la calidad de potencia. Se ha diseñado un acondicionador activo FV para transferir la máxima potencia a la red, compensar potencia reactiva y cargas no lineales. Además, se propone usar una reactancia conmutable para mejorar el seguimiento de los filtros activos. Se han probado dos índices de calidad en una red distribuida, el Load Characterizationlndex que identifica las cargas lineales y no lineales en sistemas de potencia y ei UnbalanceCurrent Ratio que asigna la responsabilidad del desequilibrio del sistema a la fuente o a la carga

Efficient Wireless Monitoring and Control of a Grid-Connected Photovoltaic System

The design, monitoring, and control of photovoltaic (PV) systems are complex tasks that are often handled together, and they are made even more difficult by introducing features such as real-time, sensor-based operation, wireless communication, and multiple sensor nodes. This paper proposes an integrated approach to handle these tasks, in order to achieve a system efficient in tracking the maximum power and injecting the energy from the PV modules to the grid in the correct way. Control is performed by means of an adaptive Lyapunov maximum power point tracking (MPPT) algorithm for the DC/DC converters and a proportional integral (PI) control for the inverters, which are applied to the system using low latency wireless technology. The system solution exploits a low-cost wireless multi-sensor architecture installed in each DC/DC converter and in each inverter and equipped with voltage, current, irradiance, and temperature sensors. A host node provides effective control, management, and coordination of two relatively independent wireless sensor systems. Experimental validation shows that the controllers ensure maximum power transfer to the grid, injecting low harmonic distortion current, thus guaranteeing the robustness and stability of the system. The results verified that the MPPT efficiency is over 99%, even under perturbations and using wireless communication. Moreover, the converters’ efficiency remains high, i.e., for the DC/DC converter a mean value of 95.5% and for the inverter 93.3%

Grid-Connected PV Systems Controlled by Sliding via Wireless Communication

Grid-connected photovoltaic (PV) systems are designed to provide energy to the grid. This energy transfer must fulfil some requirements such as system stability, power quality and reliability. Thus, the aim of this work is to design and control a grid-connected PV system via wireless to guarantee the correct operation of the system. It is crucial to monitor and supervise the system to control and/or detect faults in real time and in a remote way. To do that, the DC/DC converter and the DC/AC converter of the grid-connected PV system are controlled wirelessly, reducing costs in cabling installations. The used control methods are the sliding for the DC/DC converter and the Proportional-Integral (PI) for the inverter. The sliding control is robust, ensures system stability under perturbations, and is proven to work well via wireless. The PI control is simple and effective, proving its validity through wireless too. In addition, the effect of the communications is analysed in both controllers. An experimental platform has been built to conduct the experiments to verify the operation of the grid-connected PV system remotely. The results show that the system operates well, achieving the desired values for the maximum power point tracker (MPPT) sliding control and the energy transfer from the inverter to the grid

Wireless Sliding MPPT Control of Photovoltaic Systems in Distributed Generation Systems

The aim of a photovoltaic (PV) system’s control is the extraction of the maximum power even if the irradiance, the temperature, or the parameters vary. To do that, a maximum power point tracking (MPPT) algorithm is required. In this work, a sliding control is designed to regulate the PV modules’ output voltage and make the panel work at the maximum power voltage. This control is selected to improve the robustness, the transient dynamic response, and the time response of the system under changeable environmental conditions, adjusting the duty cycle of the DC/DC converter. The DC/DC converter connected to the PV module output is a buck-boost converter. This configuration presents the advantage of providing voltages lower or higher than supplied by the photovoltaic modules to provide the required voltage to the load (including the voltages ceded by telecommunication loads, amongst others). In addition, a remote sliding control is developed to make the global supervision of the PV system in distributed generation grids. The designed algorithm is tested in an experimental platform, both locally and remotely connected to the base station, to prove the e ectiveness of the sliding control. Thus, the communication e ect in the control is also analyzed

Centralized MPPT Controller System of PV Modules by a Wireless Sensor Network

An efficient monitoring and control system for solar photovoltaic modules, which combines the use of a non-linear MPPT backstepping controller with a custom wireless sensor network (WSN) has been developed. The infrastructure consists of a wireless smart photovoltaic system (WSPS) and a wireless centralized control system (WCC). The data of sensing, coordination and control is handled by using a WSN based on IEEE 802.15.4 technology in beacon enable mode and with guaranteed time slot. This assures the data transmission and a synchronous acquisition, which are critical elements in a wireless photovoltaic monitoring system. All measured data is gathered by an autonomous, compact and low-cost sensor node installed in each PV module, and it is transferred to the coordinator node. The power consumption of the sensor node represents only 0.25% of the power delivered by the photovoltaic module. A backstepping controller to track the Maximum Power Point (MPP) by means of a buck-boost converter derives the reference parameters to return to each PV module accordingly. The wireless solution uses low latency techniques to achieve a real-time monitoring and a stable performance of the controller. The centralized control identifies all the network nodes and significantly simplifies the maintenance operations. Experimental validation shows the robustness against interference and security in the wireless data transmission and confirms the feasibility of the proposed wireless sensor system in tracking the maximum power transfer under different weather conditions, achieving an efficiency over the 99% in the MPPT

A wireless sensor system for real-time monitoring and fault detection of motor arrays

This paper presents a wireless fault detection system for industrial motors that combines vibration, motor current and temperature analysis, thus improving the detection of mechanical faults. The design also considers the time of detection and further possible actions, which are also important for the early detection of possible malfunctions, and thus for avoiding irreversible damage to the motor. The remote motor condition monitoring is implemented through a wireless sensor network (WSN) based on the IEEE 802.15.4 standard. The deployed network uses the beacon-enabled mode to synchronize several sensor nodes with the coordinator node, and the guaranteed time slot mechanism provides data monitoring with a predetermined latency. A graphic user interface offers remote access to motor conditions and real-time monitoring of several parameters. The developed wireless sensor node exhibits very low power consumption since it has been optimized both in terms of hardware and software. The result is a low cost, highly reliable and compact design, achieving a high degree of autonomy of more than two years with just one 3.3 V/2600 mAh battery. Laboratory and field tests confirm the feasibility of the wireless system