On-board health monitoring of power modules in inverters driving induction motors

This thesis presents an on-board methodology for monitoring the health of power (converter) modules in drive systems. The ability to keep regular track of the actual degradation level of the modules enables the adoption of preventive maintenance, reducing or even eliminating altogether the appearance of failures during operation, significantly improving the availability of the power devices. The novelty of this work is twofold: the complete system that is used to achieve degradation monitoring; combining the heating technique (to obtain thermal transient) and the measurement without additional power components such as IGBT, MOSFETS, which affects the reliability, power density and complexity. The only additional component is an analog measurement circuit, which can be integrated into the gate drive board. The test routine is carried out during non-operational periods and idle times. Trains are used as a case study, where checks for degradation are made when the train is not in use, such as at the end of the day, after daily operation or at the start before daily operation and other non-operational periods. It is important to keep the train at standstill while tests are carried out. Hence a methodology to heat the devices with current from the input supply while keeping the motor load at a stand-still is presented. Experimental results obtained from this show that it is possible to implement an on-board health monitoring system in converters which measures the degradation on power modules. The work uses the concepts of vector control heating and structure function to check for degradation. It puts forward a system that is used on-board to measure the cooling curve and derive the structure function during idle times for maintenance purposes. The structure function is good tool for tracking the magnitude and location of degradation in power modules. Vector control gives the advantage of controlling the motor with field current and torque current (similar concept to DC motors)

On-board health monitoring of power modules in inverters driving induction motors

This thesis presents an on-board methodology for monitoring the health of power (converter) modules in drive systems. The ability to keep regular track of the actual degradation level of the modules enables the adoption of preventive maintenance, reducing or even eliminating altogether the appearance of failures during operation, significantly improving the availability of the power devices. The novelty of this work is twofold: the complete system that is used to achieve degradation monitoring; combining the heating technique (to obtain thermal transient) and the measurement without additional power components such as IGBT, MOSFETS, which affects the reliability, power density and complexity. The only additional component is an analog measurement circuit, which can be integrated into the gate drive board. The test routine is carried out during non-operational periods and idle times. Trains are used as a case study, where checks for degradation are made when the train is not in use, such as at the end of the day, after daily operation or at the start before daily operation and other non-operational periods. It is important to keep the train at standstill while tests are carried out. Hence a methodology to heat the devices with current from the input supply while keeping the motor load at a stand-still is presented. Experimental results obtained from this show that it is possible to implement an on-board health monitoring system in converters which measures the degradation on power modules. The work uses the concepts of vector control heating and structure function to check for degradation. It puts forward a system that is used on-board to measure the cooling curve and derive the structure function during idle times for maintenance purposes. The structure function is good tool for tracking the magnitude and location of degradation in power modules. Vector control gives the advantage of controlling the motor with field current and torque current (similar concept to DC motors)

Suboptimal filtering and nonlinear time scale transformation for the analysis of multiexponential decays

Multiexponential decays may contain time-constants differing in several orders of magnitudes. In such cases, uniform sampling results in very long records featuring a high degree of oversampling at the final part of the transient. Here, we analyze a nonlinear time scale transformation to reduce the total number of samples with minimum signal distortion, achieving an important reduction of the computational cost of subsequent analyses. We propose a time-varying filter whose length is optimized for minimum mean square erro

Preclinical MRI of the Kidney

This Open Access volume provides readers with an open access protocol collection and wide-ranging recommendations for preclinical renal MRI used in translational research. The chapters in this book are interdisciplinary in nature and bridge the gaps between physics, physiology, and medicine. They are designed to enhance training in renal MRI sciences and improve the reproducibility of renal imaging research. Chapters provide guidance for exploring, using and developing small animal renal MRI in your laboratory as a unique tool for advanced in vivo phenotyping, diagnostic imaging, and research into potential new therapies. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Cutting-edge and thorough, Preclinical MRI of the Kidney: Methods and Protocols is a valuable resource and will be of importance to anyone interested in the preclinical aspect of renal and cardiorenal diseases in the fields of physiology, nephrology, radiology, and cardiology. This publication is based upon work from COST Action PARENCHIMA, supported by European Cooperation in Science and Technology (COST). COST (www.cost.eu) is a funding agency for research and innovation networks. COST Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation. PARENCHIMA (renalmri.org) is a community-driven Action in the COST program of the European Union, which unites more than 200 experts in renal MRI from 30 countries with the aim to improve the reproducibility and standardization of renal MRI biomarkers

Compendio de métodos para caracterizar la geometría de los tejidos cerebrales a partir de imágenes de resonancia magnética por difusión del agua.

221 p.FIDMAG Hermanas Hospitalarias Research Foundation; CIBERSAM:Centro de Investigación Biomédica en Re

Suboptimal filtering and nonlinear time scale transformation for the analysis of multiexponential decays

Multiexponential decays may contain time-constants differing in several orders of magnitudes. In such cases, uniform sampling results in very long records featuring a high degree of oversampling at the final part of the transient. Here, we analyze a nonlinear time scale transformation to reduce the total number of samples with minimum signal distortion, achieving an important reduction of the computational cost of subsequent analyses. We propose a time-varying filter whose length is optimized for minimum mean square erro

Preclinical MRI of the kidney : methods and protocols

This Open Access volume provides readers with an open access protocol collection and wide-ranging recommendations for preclinical renal MRI used in translational research. The chapters in this book are interdisciplinary in nature and bridge the gaps between physics, physiology, and medicine. They are designed to enhance training in renal MRI sciences and improve the reproducibility of renal imaging research. Chapters provide guidance for exploring, using and developing small animal renal MRI in your laboratory as a unique tool for advanced in vivo phenotyping, diagnostic imaging, and research into potential new therapies. Written in the highly successful Methods in Molecular Biology series format, chapters include introductions to their respective topics, lists of the necessary materials and reagents, step-by-step, readily reproducible laboratory protocols, and tips on troubleshooting and avoiding known pitfalls. Cutting-edge and thorough, Preclinical MRI of the Kidney: Methods and Protocols is a valuable resource and will be of importance to anyone interested in the preclinical aspect of renal and cardiorenal diseases in the fields of physiology, nephrology, radiology, and cardiology. This publication is based upon work from COST Action PARENCHIMA, supported by European Cooperation in Science and Technology (COST). COST (www.cost.eu) is a funding agency for research and innovation networks. COST Actions help connect research initiatives across Europe and enable scientists to grow their ideas by sharing them with their peers. This boosts their research, career and innovation. PARENCHIMA (renalmri.org) is a community-driven Action in the COST program of the European Union, which unites more than 200 experts in renal MRI from 30 countries with the aim to improve the reproducibility and standardization of renal MRI biomarkers