42 research outputs found
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High speed induction motor and inverter drive for flywheel energy storage
The use of flywheels to store energy is a technology which is centuries old. The confluence of several modern technologies has resulted in flywheels becoming a viable solution for the needs of the transportation, electric utility, and aerospace industries. This paper discusses a high-speed induction motor and its associated inverter drive which were developed for the Federal Railroad Administration’s “Advanced Locomotive Propulsion System.” The design of the induction motor provided several significant challenges. A megawatt rated, 12,000 rpm motor operating at a rotor surface velocity speed of 230 m/s required a unique mechanical configuration to withstand the centrifugal forces as well as an electromagnetic design, which produced a high efficiency at 200 Hz. Extending the design practices used in smaller motors would not achieve the goals required for a megawatt size machine. Similarly, the inverter was developed using a soft switching technique in order to meet the demands of high power output in a compact package. Application requirements, electrical and mechanical features of the motor, design strategy for the inverter, and test results are all presented in this paper.Center for Electromechanic
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Status of the Advanced Locomotive Propulsion System (ALPS) Project
The University of Texas at Austin Center for Electromechanics (UT-CEM) is currently developing an Advanced Locomotive Propulsion System (ALPS) as part of the Next Generation High Speed Rail program sponsored by the Federal Railroad Administration (FRA). Testing of the advanced propulsion system will be conducted as a portion of the FRA Non-Electric High Speed Locomotive Demonstration program. The project goal is to develop a non-electric locomotive propulsion system capable of 150 mph operation on existing infrastructure with good fuel economy and low noise and pollutant emissions. The propulsion system consists of two major elements: (1) a high speed generator directly coupled to a 5,000 hp gas turbine (turboalternator) to provide prime power and (2) an energy storage flywheel to provide additional power for acceleration and speed maintenance on grades, and to recover kinetic energy during braking. In addition to improving the overall system efficiency, the energy storage flywheel also provides load leveling for the turbine, reducing thermal cycling and significantly extending turbine maintenance intervals. The paper provides an overview of the ALPS system and presents the results of performance simulations to illustrate the benefits of the system. The paper also provides the current status of the project, along with component test results as available.Center for Electromechanic
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Critical Design Factors in the Development of a Hybrid Electric Advanced Locomotive Propulsion System
Hybrid electric propulsion systems have been applied to a range of vehicles, from compact passenger cars to transit buses and rail vehicles. These systems offer improved performance, increased fuel efficiency and reduced emissions. The University of Texas at Austin Center for Electromechanics (UTCEM) is developing a hybrid electric propulsion system for high speed non-electric passenger locomotives as part of the Federal Railroad Administration’s Next Generation High Speed Rail program. The Advanced Locomotive Propulsion System (ALPS) project, introduced at the Fall VTC-2003 conference, seeks to demonstrate technology for a fossil fueled hybrid-electric locomotive propulsion system capable of operation at speeds up to 150 mph on existing infrastructure with acceleration comparable to current generation electric locomotives. Lightweight, high performance fossil fueled locomotives will facilitate the expansion of high speed passenger rail by providing energy efficiency and trip times comparable to electrified systems without the $3-5M per track mile cost of electrification.Center for Electromechanic
Functional Anatomy of the Female Pelvic Floor
The anatomic structures in the female that prevent incontinence and genital organ prolapse on increases in abdominal pressure during daily activities include sphincteric and supportive systems. In the urethra, the action of the vesical neck and urethral sphincteric mechanisms maintains urethral closure pressure above bladder pressure. Decreases in the number of striated muscle fibers of the sphincter occur with age and parity. A supportive hammock under the urethra and vesical neck provides a firm backstop against which the urethra is compressed during increases in abdominal pressure to maintain urethral closure pressures above the rapidly increasing bladder pressure. This supporting layer consists of the anterior vaginal wall and the connective tissue that attaches it to the pelvic bones through the pubovaginal portion of the levator ani muscle, and the uterosacral and cardinal ligaments comprising the tendinous arch of the pelvic fascia. At rest the levator ani maintains closure of the urogenital hiatus. They are additionally recruited to maintain hiatal closure in the face of inertial loads related to visceral accelerations as well as abdominal pressurization in daily activities involving recruitment of the abdominal wall musculature and diaphragm. Vaginal birth is associated with an increased risk of levator ani defects, as well as genital organ prolapse and urinary incontinence. Computer models indicate that vaginal birth places the levator ani under tissue stretch ratios of up to 3.3 and the pudendal nerve under strains of up to 33%, respectively. Research is needed to better identify the pathomechanics of these conditions.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72597/1/annals.1389.034.pd
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Field Excitation and Discharge Switching for Air-Core Compulsators
The Center for Electromechanics at The University of Texas (CEM-UT) has designed and built three generations of air-core compulsators for railgun application. These systems rely on compact power electronics to provide rapid self-excitation of the field windings and control of the main current discharge. All three systems built so far have been single-phase armature machines. The parameters for these systems range from 20 to 42 kA field excitation at 125 to 400 Hz rectification and 2.5 to 12 kV. The main discharge peak current ranges from 0.3 to 3 MA. The design and performance of past switching systems is reviewed and the prospects for further mass and volume reductions is presented.Center for Electromechanic
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Testing Pulsed Current Conditioning to Benefit Vehicle Battery Performance
Calorimetric testing of pulsed power conditioning, as an influence on a battery's electrochemical transfer efficiency, is presented. The experiment used two 300 AH (ampere-hour) electric shuttle bus batteries; alternately charging and discharging at 8 to 14 kW with two charge and three discharge modes. The batteries were thermally insulated and monitored to analyze energy balance differences. The test setup, results, and analyses are reported. While slight trends were seen, improved transfer efficiencies due to pulsed currents could not be confirmed. Benefits under conditions of much higher transfer rates or for battery life cycle improvements are considered but were not tested.Center for Electromechanic
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Pulse Discharge Control and Machine Protection for a Multi-Discharge Compulsator
A compensated pulse alternator (compulsator) to power railgun research experiment has been designed and built. The author presents the control design considerations and strategies used in the control of proper output pulses and the detection and clearing of faults. Since the compulsator is designed for limited pulse duty, particular emphasis is placed on reliability and redundancy in the fault-control system to avert potentially massive generator damage. The circuit has provided reliable performance through the system testing. Other circuits, designed to protect the compulsator from short-circuit fault damage, have also been successfully implementedCenter for Electromechanic
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Power Electronics in the 9 MJ EM Range Gun System
The Center for Electromechanics at the University of Texas at Austin (CEM-UT) is developing an open range demonstrator electromagnetic (EM) gun system with specific size and mass constraints. The design being pursued includes a single phase full bridge rectifier and inverter to accomplish a self generated field excitation and regenerative field energy recovery. The peak power of the excitation system is over 600 MW, performing for single second operations at a repetition rate of once every 20 s over 3 min. The design also includes a solid-state thyristor switch for firing the railgun. This switch closes for one half cycle of ac current, reaching over 3,000,000 A and lasting up to 6 ms. The open circuit rms voltage is 4.2 kV at 125 Hz. These power electronics subsystems have been designed to be compact and lightweight. This paper presents the design parameters, packaging, and control strategies employed.Center for Electromechanic