Physical Scale Model Alternators as a Pulsed-Power Source Simulator

Shepard, N. F.; Chen, Y.Y.; Mallick, J.

doi:10.1109/tmag.2006.887673

Cited by 9 publications

(5 citation statements)

References 1 publication

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“…This turned out to be quite straightforward, once the proper thyristor control algorithm had been developed [1] and experiments with pulsed power operation under resistive loads had taken place. We then expanded the scope and goals to determine whether 60-Hz alternators could be used as pulsed power sources and to study the effects of a pulsed alternator pair with differing electrical characteristics.…”

Section: Discussionmentioning

confidence: 99%

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Experimental Results from a Physical Scale Model Alternator Pair as a Pulsed Power

2007

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The Institute for Advanced Technology is using a pair of physical scale model alternators as counter-rotating pulsed alternator simulators. These alternators have similar but not identical electrical characteristics. The original goal was to use these alternators to simulate a two-machine pulsed alternator system to study thyristor converter operation, with the two machines electrically connected at the output (dc side) of the thyristor (SCR) converter. Additional experiments were also run with the two alternators electrically connected at the input (ac side) of the thyristor converter. In the experiments, control algorithms were developed to test self-excitation and to discharge pulsed energy into various types of loads-resistive, inductive, and capacitive-to evaluate energy sharing from each alternator. Negative resistance circuits were implemented to adjust the field winding time constant of each alternator to achieve correct resistance/reactance ratio of full-scale pulsed alternators and to achieve equal energy discharge from each alternator.Index Terms-Alternator pair, alternator simulator, pulsed alternator, physical scale model, source simulator.

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Section: Discussionmentioning

confidence: 99%

“…1, and used to simulate counter-rotating pulsed alternators. The simulator incorporated a digital-signal, processor-based, real-time control system for thyristor converter operation [1]. The alternators have a power rating of approximately 1 kW at 60 Hz and are similar in construction but with different electrical constants [2], [3].…”

Section: Introductionmentioning

confidence: 99%

Experimental Results from a Physical Scale Model Alternator Pair as a Pulsed Power

2007

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“…Kitzmiller [7] proposed the principle of positivefeedback self-excitation, which typically involves initiation using, a small capacitor-based power supply, and examined the important aspects to consider when designing a proper field initial module. Nathan Shepard et al [4] presented the self-excitation mode and introduced a control method for the self-excitation procedure. Ye [8], introduced the pulseexcitation mode, which could be operated at a higher discharge frequency, and also analyzed the differences between self-excitation and pulse-excitation systems.…”

Section: Introductionmentioning

confidence: 99%

Analytical Investigation and Scaled Prototype Tests of a Novel Permanent Magnet Compulsator

et al. 2015

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Compensated pulsed alternators (compulsators) is one of the most popular choices of pulsed power supplies for fusion reactors, high-power pulsed lasers, and hypervelocity electromagnetic launchers because of its high energy density and power density. In general, external excitation in the form of self-excitation or pulse-excitation is adopted in compulsators together with iron-core or aircore. Those results in heavy, bulky components and a system that is more complicated and less reliable. In this paper, a novel compulsator is proposed which is excited using a permanent magnet (PM) and is equipped with an iron-core or air-core stator. An excitation converter or brush-slip ring system is not needed in the novel system which consequently makes it more reliable, less massive, and less voluminous than external excitation machines. In addition, the novel PM compulsator acts not only as a pulsed alternator capable of delivering high-power pulses, but also as a brushless PM DC motor that can be employed to charge the energy storage rotor. Thus, no external driving motor or gearbox is needed in the pulsed power system, which makes the system integrated and compact. In this paper, analytical models for the air gap magnetic distribution, the back-electromotive force, and the pulsed current waveform of the machine are deduced. A PM Compulsator is designed and analyzed, and a scaled prototype of the PM compensated pulsed alternator is fabricated and tested. The actual output voltage waveforms and pulsed-current waveforms are sampled and compared with the predicted ones and clearly demonstrate that the design of the PM compulsator is feasible.Index Terms-Pulsed power supply, pulsed alternator, compulsator, PM compulsator, flywheel energy storage, electromagnetic launcher, analytical method.

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“…In this paper, specific cases and their sensitivities have been studied, and a motoring scheme is suggested that helps the process of synchronization. Shepard et al [3] and Chen et al [4] have done some work in this area; however, they used two machines that were very dissimilar such that, under discharge, one acted as a motor and the other as a generator, so current sharing between the generators was not established. Fig.…”

Section: Introductionmentioning

confidence: 99%

Synchronization of Multiple Pulsed Alternators Discharging Into an EM Launcher

Pratap

Zowarka

Hotz

et al. 2015

IEEE Trans. Plasma Sci.

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Abstract-As the energy level in the projectile increases it becomes necessary to use multiple pulsed alternators discharging in parallel into the EM launcher. Another reason for having more than one machine is to compensate torque and gyroscopic effects of the pulsed alternator. This requires that machines be built in counterrotating pairs. These machines are identical in all respects except for their direction of rotation. A study was conducted to determine how the machines can be motored so that they stay in lock step in speed and phase as they are motored to full speed. The methods of connecting these multiple machines are discussed. The aim of the connection scheme is to allow the machines to naturally stay locked in speed and phase throughout its operating range. Sensitivity of the performance of these machines to small variations in the machine parameters, which is to be expected in the machines, is discussed. Sensitivity of the discharge performance to small phase angle mismatches due to tolerances is also discussed.To verify the conclusions of the study an experiment was performed on two identical 50 kVA machines discharging into a low impedance load. The motoring system that is discussed in the study was implemented in this experiment which kept the machines in lock step. This motoring system is described. Thereafter discharges were made at various speeds and field current levels. Phase angle mismatches were introduced between the two machines to see how it affected current sharing. The results and conclusions of these tests are presented in this paper.

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Physical Scale Model Alternators as a Pulsed-Power Source Simulator

Cited by 9 publications

References 1 publication

Experimental Results from a Physical Scale Model Alternator Pair as a Pulsed Power

Experimental Results from a Physical Scale Model Alternator Pair as a Pulsed Power

Analytical Investigation and Scaled Prototype Tests of a Novel Permanent Magnet Compulsator

Synchronization of Multiple Pulsed Alternators Discharging Into an EM Launcher

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