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In this paper, a terminal sliding mode (TSM) controller is designed for boost converter with purpose of robustness and better response against circuit nonlinearities and disturbances. Instead of using the commonly used average model or switching model for current-mode controlled (CMC) boost converter, a novel energy storage function (ESF) model is proposed for TSM controller, which contains all of...
This paper proposes an algorithm to select dynamically an appropriate threshold for basic amplitude sampling transmission strategies (also called Send-on-Delta SoD strategies) given an available transmission rate. It is based on previously found relationships between threshold and throughput, and on justified approximations. The algorithm is presented to be computed in a Send-on-Delta (SoD) driver...
This paper presents a networked control scheme for a photovoltaic-based industrial microgrid to adaptably operate in both grid-connected and islanded modes, and even to transfer smoothly between these two modes. The control scheme is mainly based on the droop method for active and reactive power sharing by means of voltage and frequency regulation. In addition, to get a smooth transfer between islanded...
Previous research have shown the advantages of a novel Technical Vision System (TVS), developed at the Autonomous University of Baja California (UABC), which uses triangulation to determine spatial coordinates on any object under observation. Present paper proposes a new application for the TVS use on drones with remote laser scanner in agriculture to determine a vegetation index of scanned crops...
An approach for thermal control of an electric heating system having halogen lamp heaters driven by AC line voltage with zero-cross switch is proposed. The feeding power is governed with a delta-sigma modulator estimating the resistance of the halogen lamps dynamically to evaluate the instantaneous feeding power. The thermal model of the halogen heater is identified with the linear functional model...
In view of the fact that the integration of ICs is becoming higher and accessible testing nodes are getting less, circuit testing is becoming more and more difficult. A multidimensional feature fault diagnosis method based on principal component analysis is proposed in this paper. On the basis of analyzing the fault feature of analog circuits, the fault diagnosis method of multiple fault features...
Condition monitoring (CM) is of great significance to ensure the reliability of systems. With the wide use of power electronic equipment in multiple fields, the CM technology for power electronics has become more important. Feature parameter extraction is the prerequisite to realize CM of power electronic circuits. A unified method to extract parameters of the Buck converter with different properties...
When Lamb waves propagates in composite laminates, the direction-dependent property parameters of the composite laminates lead to different propagation velocities, which is known as the anisotropy nature. It makes the problem of damage detection more difficult. A sparse reconstruction based damage imaging method considering the anisotropy nature of composite laminates is presented in this paper. A...
In recent years several statistical methods have been applied to condition monitoring of various processes under linearity and stationarity assumptions. However most of the actual industrial processes, e.g. in the chemical sector, are strongly nonlinear. Furthermore the hypothesis of data Gaussian distribution does not often hold, thus causing a decrease of the fault detection accuracy. In this paper...
The problem of robust linear and nonlinear diagnostic observers design is considered. The method to construct the observers invariant with respect to the disturbances or having minimal sensitivity to the disturbances is suggested. It is based on logic-dynamic approach which allows to consider the systems with non-differentiable nonlinearities by linear methods. Besides, the method allows to obtain...
Leak detection is vital in oil and gas pipelines, as it can cause financial loss and impact the environment, prove fatal to human life and also affect the effective functioning of domestic household. Acoustic emission test is a non-intrusive technique for leak detection. Leakage in pipes creates vibrations which are transmitted along the pipe walls. These waves can be detected by using acoustic sensors...
Water ingress problem caused by gas leaks in distribution gas pipeline is a rather thorny problem, which the gas companies typically encounter. Replacing the existing faulty pipeline is rather costly and troublesome. For gas pipelines, when leak happens, gas escapes from the pipelines into the free space or surrounding environment, and results in cooling of the nearby area due to the Joule-Thomson...
Confusion of frequency spectrum under varying speed condition leads to the efficacy degradation of fault recognition for rolling element bearings. Meanwhile, a widely-used method is transforming non-stationary vibration signals into angular domain based on angular re-sampling to reduce influence of speed fluctuation. However, single domain usually cannot describe health information comprehensively...
The problem of fault diagnosis in technical systems with uncertainties described by linear discrete-time models is studied within the scope of analytical redundancy concept. Solution of the problem assumes the checking redundancy relations existing among system inputs and outputs measured over a finite time window. The non-parametric method is considered to construct redundancy relations involving...
This paper presents a diagnosis method for open-transistor faults in voltage-source inverter (VSI) based on output phase voltages. When fault occurs, the faulty phase voltage will vanish during certain half periods, which can be utilized for diagnosing. In order to reduce calculation and improve noise resistance, the sliding-window counting method with first-in-first-out algorithm are introduced to...
Power MOSFET is one of the most rapidly aging components in power electronic converters, and some study of the health monitoring of power MOSFETs is made in this paper. This paper proposes a threshold voltage-based real-time aging monitoring method for power MOSFETs in Buck converters. Firstly, the origins of degradation in power MOSFETs are analyzed, and the junction temperature is indicated to be...
The detection, diagnostic, and prognostic of power transistor degradation play a key role in increasing the reliability and safety of power electronic converters (PECs), especially in aeronautic and astronautic fields. In a PEC, high-frequency oscillation may occur during the switching transients of power transistors, which is known as ringing. The switching ringing reflects the intrinsic parameters...
Nowadays, industrial plants are calling for high-performance fault diagnosis techniques to meet stringent requirements on system availability and safety in the event of component failures. This paper deals with robust fault estimation problems for stochastic nonlinear systems subject to faults and unknown inputs relying on Takagi-Sugeno fuzzy models. Augmented approach jointly with unknown input observers...
Gas pipelines are the most vital and commonly used method of transportation of fuel, water, gas. Any form of leak in the pipeline can be catastrophic to mankind, incurring huge financial losses. In this paper, an experimental study has been carried out with respect to a real-time monitoring on the pressure and the flow variations. A small section of the pipeline with valves is considered to generate...
High resolution and accurate location are the crucial goals associated with the application of guided waves for nondestructive testing purposes. In this paper, through experimental studies, the influences of the frequency-dependent amplitude to the testing resolution of guided wave methods are investigated. Firstly, the factors which result in frequency dependency to the amplitude characteristic of...
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