Online Monitoring

This paper proposes a method to extract the junction temperature of high-voltage and high-power P-iN diodes. It is investigated that the swept-out charge during reverse recovery current fall time is affected by junction temperature variation, which makes the swept-out charge a possible thermo-sensitive electrical parameter (TSEP). Thanks to the specific package of high-power IGBT modules with P-iN diodes, the swept-out charge of a P-iN diode can be measured by the induced voltage v eE on the parasitic inductor L eE between Kelvin and power emitter terminals. In typical inductive half-bridge circuit, the comprehensive analysis of commutation between the upper P-iN diode and lower enabled IGBT, discloses the monotonic relationship among the reverse recovery charge, reverse current fall time, and junction temperature. A double pulse chopper circuit is used to validate the theoretical analysis. The experimental results show that the dependency between diode junction temperature and charge during the reverse recovery current fall time is approximately linear. A 3-D look-up table is calibrated and can be used to estimate the P-iN diode junction operating temperature. Finally, an experimental comparison of four TSEPs for P-iN diode is presented to verify the feasibility of implementation of proposed TSEP. Index Terms-High-power P-iN diodes, thermo-sensitive electrical parameter, reverse recovery charge, junction temperature extraction.

Scan2Map is an airborne remote-sensing system developed under the lead of the TOPO lab at the EPFL. Typically operated aboard a helicopter, it is dedicated for small mission areas (a few square kilometres at the maximum) and offers a sub-decimetre accuracy of the derived mapping products (orthophotos, digital surface- and terrain models). To achieve this high quality independently from ground

The paper proposes a distributed sensor network based on a wireless BlueTooth communication system or Power Quality (PQ) assessment in power systems. The architecture of the sensor node is described and characterized, together with the analysis of the measurement and communication procedure able to perform the PQ indices evaluation according the IEC 61000-4-30 norm. The necessity of online monitoring quantities spread on a wide geographical area have required the realization of intelligent measurement systems able to analyze and interpret large amounts of data into meaningful conclusions. The main element of these systems is a great quantity of low-cost, low-power,

Defect in welded structures is a matter of serious concern. The current practice involves interpretation by inspectors and experts, of radiographs after the weld is completed which is time consuming. With greater emphasis on automation during manufacturing process, automated NDT has gained prominence. One of the Non Destructive Evaluation (NDE) techniques that is being increasingly applied for online monitoring is

The use of the internet of things (IoT) in solar photovoltaic (PV) systems is a critical feature for remote monitoring, supervising, and performance evaluation. Furthermore, it improves the long-term viability, consistency, efficiency, and system maintenance of energy production. However, previous researchers' proposed PV monitoring systems are relatively complex and expensive. Furthermore, the existing systems do not have any backup data, which means that the acquired data could be lost if the network connection fails. This paper presents a simple and low-cost IoT-based PV parameter monitoring system, with additional backup data stored on a microSD card. A NodeMCU ESP8266 development board is chosen as the main controller because it is a system-on-chip (SOC) microcontroller with integrated Wi-Fi and low-power support, all in one chip to reduce the cost of the proposed system. The solar irradiance, ambient temperature, PV output voltage and PV output current, are measured with p...

The use of the internet of things (IoT) in solar photovoltaic (PV) systems is a critical feature for remote monitoring, supervising, and performance evaluation. Furthermore, it improves the long-term viability, consistency, efficiency, and system maintenance of energy production. However, previous researchers' proposed PV monitoring systems are relatively complex and expensive. Furthermore, the existing systems do not have any backup data, which means that the acquired data could be lost if the network connection fails. This paper presents a simple and low-cost IoT-based PV parameter monitoring system, with additional backup data stored on a microSD card. A NodeMCU ESP8266 development board is chosen as the main controller because it is a system-on-chip (SOC) microcontroller with integrated Wi-Fi and low-power support, all in one chip to reduce the cost of the proposed system. The solar irradiance, ambient temperature, PV output voltage and PV output current, are measured with p...

Additive Manufacturing (AM) is a process which is based on manufacturing parts layer by layer in order to avoid any geometric limitation in terms of creating the desired design. In the early stages of AM development, the goal was just creating some prototypes to decrease the time of manufacturing assessment. But with metal-based AM, it is now possible to produce end-used parts. In powder-based AM, a designed part can be produced directly from the STL file (Standard Tessellation Language/stereolithography) layer by layer by exerting a laser beam on a layer of powder with thickness between 20 µm to 100 µm to create a section of the part. The Achilles' heel of this process is generation of some defects during the process weakening the mechanical properties and in some cases these defects can even lead to part failure under manufacturing. This prevents the technology from spreading widely and limits the repeatability and precision of the process. Online monitoring (OM) and intelligent control is a feasible approach that is investigated prevalently in order to monitor the generated defects and eliminate them real-time. In this regard, this paper reveals the most frequent and traceable defects which significantly affects quality matrices of the produced part in powder-based AM with focusing on Selective Laser Sintering (SLS) process. These defects are classified into " Geometry and Dimensions " , " Surface Quality (Finishing) " , " Microstructure " and the defects behind " Weak Mechanical Properties " In addition, we introduce and classify the most important parameters which can be monitored and controlled to avoid those defects or they can be employed in some error handling strategies to remove the generated defects. We also introduce some signatures that can be monitored for adjusting the parameters into their optimum value instead of monitoring the defects directly.

Clinical information systems can record numerous variables describing the patient's state at high sampling frequencies. Intelligent alarm systems and suitable bedside decision support are needed to cope with this flood of information. A basic task here is the fast and correct detection of ...

Analog and mixed signal (AMS) circuits play an important role in today's System on Chip design. They pose, however, many challenges in the verification of the overall system due to their complex behavior. Among many developed verification techniques, runtime verification has been shown to be effective by experimenting finite executions instead of going through the whole state space. In this paper, we present a methodology for the specification and verification of AMS designs using online monitoring at runtime based on the notion of System of Recurrence Equations (SREs). We implement the proposed methodology in a C language based tool, called C-SRE, and utilize it to verify several properties of a PLL design. We compare our proposed online monitoring techniques with the offline approach. Finally, we apply the proposed methodology to monitor the jitter noise associated with a voltage controlled oscillator.

We compare the performance of two phase II monitoring schemes for linear profiles, one based on the classical calibration method monitoring the deviations from the regression line (referred to as the NIST method) and the second based on individually monitoring the parameters of the linear profile (referred to as the KMW method). The comparison criterion is average run length performance

In the present paper corrosion of iron (99.95%) and iron–chromium alloys (1–5% Cr) were investigated by mass loss and ac impedance. These low-chromium content alloys have been proposed as an intermediate corrosion-performance material between C-steel and stainless steels to be used in oil plants. It was observed that small contents of chromium in the alloy decrease the corrosion attack only

Abstract—FLUKA Monte Carlo simulations have been per-formed to identify particle energy spectra and fluences relevant for evaluating the risk of single event effects in electronics installed in critical LHC underground areas. Since these simulations are associated with significant ...

Franke, H., Streckert, J., Bitz, A., Goeke, J., Hansen, V., Ringelstein, E. B., Nattkamper, H., Galla, H-J. and Stogbauer, F. Effects of Universal Mobile Telecommunications System (UMTS) Electromagnetic Fields on the Blood-Brain Barrier In Vitro. Radiat. Res. 164, 258-269 (2005). The extensive use of mobile phone communication has raised public concerns about adverse health effects of radio- frequency (RF) electromagnetic