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A comparative human performance evaluation of a miner's walking speed and head pitch was conducted on miners wearing two types of LED cap lamps. Walking speed and head pitch are indirect indicators of improved lighting. The better that miners can see the floor, the faster they can walk and the less they pitch their heads downward to illuminate the floor with their cap lamps. NIOSH researchers developed...
This paper deals with the setting parameter optimization procedure for a multi-phase induction heating system considering transverse flux heating. This system is able to achieve uniform static heating of different thin/size metal pieces without movable inductor parts, yokes or magnetic screens. The goal is reached by the predetermination of the induced power density distribution using an optimization...
This paper presents the analyzed results of stability enhancement of a grid-connected offshore wind farm (OWF) using a superconducting magnetic energy storage (SMES) unit. The fuzzy damping controllers of the proposed SMES unit are designed by using fuzzy control theory to contribute effective damping to the studied 80-MW OWF based on doubly-fed induction generator (DFIG) under various disturbance...
This paper deals with an implementation of a Distribution Static Compensator (DSTATCOM) using an adaptive filter based control algorithm for power quality improvement under linear/nonlinear loads in a three phase distribution system. The proposed control algorithm based on adaptive synchronous extraction is used for extraction of fundamental active and reactive power components of load currents for...
In underground coal mines, medium frequency (MF) communication systems couple their signals to metal infrastructures such as AC power cables and wire-based telephone lines, which guide the signals to propagate for a long distance. To better understand the propagation characteristics of MF signals, an easy-to-use measurement method was recently developed at the National Institute for Occupational Safety...
Diesel exhaust emissions legislation is driving acceptable NOx emissions to ever lower levels. To continually meet the challenges presented by this trend, new SCR controls technologies must be considered as well as new ways to sense and control them. Ammonia storage controls technology was developed to manage ammonia utilization within a Selective Catalytic Reduction (SCR) sub-system and thereby facilitate...
This paper presents an intelligent control strategy for improving energy efficiency of a commercial building using a multi agent system architecture. The proposed MAS based control minimizes the amount of required energy while maintaining comfort for the occupants of a building. Models for thermal and electrical systems for a prescribed area of a building are developed and the generality of the solution...
This paper presents an electronic ballast to supply a 70W high pressure sodium lamp. The electronic ballast consists on a single-stage converter that integrates a buck converter to provide power factor correction and two flyback converters to supply the lamp, with low frequency square waveform, in order to avoid the acoustic resonance phenomenon occurrence. It is proposed one study, qualitative and...
Stage lighting with high intensity discharge lamp is always regarded as an important method to present artistic scenery, stage lighting changed with rhythm and/or theatricality and/or voice would bring about more visual convulsion to the audiences. A novel flicking idea for stage lighting is proposed in this paper, the operation principle for light flicking with high pressure sodium lamp is analyzed,...
This paper presents a simplified envelope model to study the dynamics of a phase-controlled resonant converter suitable to drive light emitting diode (LED) lamps. The output current is controlled, at constant switching frequency, through the phase displacement, Ψ, of the control signals of each class D section of the resonant inverter stage. The envelope model of the resonant network is reduced to...
This paper presents an electronic ballast for driving HID lamps with low frequency square waveform from a DC supply suitable for low power low voltage applications as automotive. From the DC source, a flyback arrangement is inserted into a switching structure whose output provides low frequency voltage yet avoiding instability issues. Proposal's main advantage is the use of one single choke of simple...
Conventional direct torque control (DTC) for permanent magnet synchronous motor (PMSM) has some shortcoming of more torque fluctuation, current fluctuation and inconstant switching frequency. Through an analysis of surface mounted permanent magnet synchronous motor (SPMSM), a new DTC-SVM (space vector modulation) method with a flux observer based on rotor position and current model, fast reference...
Dimmable high-power-factor electronic ballast is proposed in this paper. The electronic ballast is intended to feed a 100 W electrodeless fluorescent lamp (EFL) at 250 kHz. The proposed topology consists of a buck-boost converter, as power factor correction (PFC) stage, associated with a resonant halfbridge inverter, used as lamp power control (PC) stage. In this work, the integration of both stages...
This paper presents an online trained fuzzy logic and adaptive wavelet based high precision fault detection of broken rotor bars for squirrel cage induction motor (IM). Motor faults which consist of broken rotor bars, bearing decay, eccentricity, etc. appears as different frequencies in the stator current signals. The winding function is used to obtain stator current and speed signals at different...
A new physics-based and computationally efficient drain current model for oxide semiconductor thin film transistors (TFTs) is developed. In this model, the influence of trap states in the band gap is taken into account to reproduce the gradual increase of the subthreshold current. Analytical expressions for the trapped electron densities are used to reduce the calculation time when solving the Poisson...
We have developed MulDiRoH, a human representation system comprising a multi-view display that uses a QDA screen and multiple cameras. The use of the QDA screen offers the benefit of a large, wide viewing area that enables observers to comfortably watch the display. It also provides convenience in that it is unnecessary to accurately orient the projectors, which facilitates easy system construction.
This paper presents an extended back electromotive force (EMF)-based discrete sliding-mode observer (SMO) for rotor position/speed sensorless control of interior permanent magnet synchronous machines (IPMSMs). Normally, the dead-time effects in voltage source inverters are often ignored or assumed to be fully compensated when designing a position observer. However, for high-voltage and high-power...
We describes in this paper the robustness of optical watermarking against the defocusing of images, which usually occurs in images taken with digital cameras under nonoptimal conditions. We evaluated measurements of the defocusing of images against the accuracy of detection of optical watermarking. The value of full width at half maximum (FWHM) of the Gaussian function was used to measure the defocusing...
We have developed a high-frame-rate LED display. Full-color images with high brightness are refreshed at 480 frames per second. In order to transmit such a high framerate signal via conventional 120-Hz DVI, we have introduced a spatiotemporal mapping for its signal input. Four adjacent pixels in each frame in DIV signal are converted into successive four fields. This spatiotemporal mapping improves...
In this paper, a maximum-power-point-tracking (MPPT) photovoltaic wide load-range zero-voltage-switching (ZVS) phase-shift full-bridge (PSFB) charger with DC-link current regulation is developed in order to obtain high-efficiency power conversion even at light load condition. According to the output characteristics of the solar cell module, the proposed MPPT photovoltaic converter can be implemented...
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