نتایج جستجو برای: ac drives
تعداد نتایج: 68145 فیلتر نتایج به سال:
Although the global spread of the emerging zoonosis, human angiostrongyliasis, has attracted increasing attention, understanding of specific gene function has been impeded by the inaccessibility of genetic manipulation of the pathogen nematode causing this disease, Angiostrongylus cantonensis. Many parasitic proteases play key roles in host-parasite interactions, but those of A. cantonensis are...
Submitted: Apr 21, 2013; Accepted: Jun 4, 2013; Published: Jun 22, 2013 Abstract: This paper presents a pulse doubling technique in a 36-pulse ac-dc converter which supplies direct torque-controlled motor drives (DTCIMD’s) in order to have better power quality conditions at the point of common coupling. The proposed technique increases the number of rectification pulses without significant chan...
AC drives are employed mainly in process plants for various applications. In most industrial applications, Induction motor preferred as they robust, reliable, and efficient. Process industries have seen a paradigm shift from manual control to automatic control. Advancements power electronics technology led smooth of the induction using variable frequency over an entire speed range. Variable Fre...
Most of the ac-ac converters used in home-appliances are based on single-output dc-link inverters, which provides a cost-effective and straight-forward solution. However, this twostage power conversion decreases power density and efficiency. Direct ac-ac conversion has been thoroughly studied in the past. However, the complex control scheme and higher cost has prevented it from being used in lo...
induction motors are the most commonly used in the traction industries and electric vehicles, due to their low primary cost, low maintenance costs, and good performance. speed identification is needed for the induction motor drives. however, using of speed sensors in the induction motor drives is associated with problems such as, extra cost, reduced reliability, added mounting space, etc.. ther...
odically occur in a facility’s electrical system can cause equipment malfunction, data distortion, transformer and motor insulation failure, overheating of neutral buses, nusiance tripping of circuit breakers, and solid-state component breakdown. The cost of power quality problems can be enormous. Equipment replacement can cost tens of thousands of dollars. Downtime, however, can run in the mil...
This project proposes a novel three phase nine switch AC/AC converter topology. This converter features sinusoidal inputs and outputs, unity power factor, and more importantly, low manufacturing cost. The Operating principle of the Converter is elaborated, its modulation schemes are also discussed, and experimental results from a 5kVA prototype system are provided.
The purpose of this paper is to show the working limits of a Variable Speed Wind Turbine. The system is based on a Doubly-Fed Induction Generator and a Fixed-Pitch Wind Turbine. The machine rotor is connected to the network through an AC/AC Converter in order to allow energy recovery. Thermal, mechanical and electric limits are investigated. The study of the machine is based on a steady state m...
Railway traction is a more stochastic heavy load connected system. Due to the usage of ac-dc converters and ac-ac converters, the various power quality issues become the major problems in the electric system. This paper presents a review on power quality conditioners suitable for Railway traction based on the configuration, components involved and on the technical and economic considerations. M...
We examine the ultraviolet (UV)-sensitive part of the one-loop Casimir energy which is induced when various higher-dimensional supergravities are com-pactified to 4D on extra dimensions which are Ricci flat, but otherwise arbitrary. We identify the leading dependence on the mass of very massive higher-dimensional modes, as well as the UV divergent part of the contributions of modes which are ma...
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