A Tesla-Blumlein PFL-Bipolar pulsed power generator

A Tesla-Blumlein PFL-Bipolar pulsed power generator, has been successfully designed, manufactured and demonstrated. The compact Tesla transformer that it employs has successfully charged capacitive loads to peak voltages up to 0.6 MV with an overall energy efficiency in excess of 90%. The Tesla driven Blumlein PFL generator is capable of producing a voltage impulse approaching 0.6 MV with a rise time close to 2 ns, generating a peak electrical power of up to 10 GW for 5 ns when connected to a 30 Ω resistive load. Potentially for medical application, a bipolar former has been designed and successfully implemented as an extension to the system and to enable the generation of a sinusoid-like voltage impulse with a peak-to-peak value reaching 650 kV and having a frequency bandwidth beyond 1 GHz. This thesis describes the application of various numerical techniques used to design a successful generator, such as filamentary modelling, electrostatic and transient (PSpice) circuit analysis, and Computer Simulation Technology (CST) simulation. All the major parameters of both the Tesla transformer, the Blumlein pulse forming line and the bipolar former were determined, enabling accurate modelling of the overall unit to be performed. The wide bandwidth and ultrafast embedded sensors used to monitor the dynamic characteristics of the overall system are also presented. Experimental results obtained during this major experimental programme are compared with theoretical predictions and the way ahead towards connecting to an antenna for medical application is considered

Laser action in run-away electron preionized diffuse discharges

Formation features of run-away electron preionized diffuse discharge (REP DD) and REP DD properties in different experimental conditions are studied. It was shown that sufficient uniformity of REP DD allows its application as an excitation source of lasers on different gas mixtures at elevated pressure. Promising results of REP DD application for development of gas lasers are shown. Stimulated radiation in the IR, visible and UV spectral ranges was obtained in the diffuse discharge. Ultimate efficiency of non-chain HF(DF) chemical and nitrogen lasers on mixtures of SF6 with H2(D2) and N2 was achieved. New operation mode of nitrogen laser is demonstrated under REP DD excitation. Kinetic model of the REP DD in mixtures of nitrogen with SF6 is developed allowing to predict the radiation parameters of nitrogen laser at λ = 337,1 nm. Long-pulse operation of rare gas halide lasers was achieved. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Efficient gas lasers pumped by run-away electron preionized diffuse discharge

It was shown that run-away electron preionized volume (diffuse) discharge (REP DD) can be used as an excitation source of active gas mixtures at elevated pressures and can produce laser emission. We report experimental and calculated results of application of the REP DD for excitation of different active gas mixtures. It was shown that the REP DD allows to obtain efficient lasing stimulated radiation in the IR, visible and UV spectral ranges. Kinetic model of the REP DD in mixtures of nitrogen with SF6 is developed allowing to predict the radiation parameters of nitrogen laser at 337.1 nm. Promising prospects of REP DD employment for exciting a series of gas lasers was demonstrated. Lasing was obtained on molecules N2, HF, and DF with the efficiency close to the limiting value. It was established that the REP DD is most efficient for pumping lasers with the mixtures comprising electro-negative gases. © (2015) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only

Assessing battery energy storage for integration with hybrid propulsion and high energy weapons

In the future warship power and propulsion systems need to be designed for increased flexibility, in part to sustain the demand of changing load profiles such as those characterised by high ramp-rates of new weapons and sensors intended to support enhanced future warfighting capability. Lithium-ion based battery performance is improving at a prominent pace in the automotive sector, increasing in both energy and power density, thus there is now an opportunity to exploit these characteristics for naval power systems. A common use energy storage system could facilitate benefits such as reduced fuel burn and prime mover running hours by reducing the number of running generator sets. Importantly, the improvement in battery systems, has reached a juncture where the technology could be considered to support directed energy weapons. The feasibility of a Lithium-ion NMC based energy storage system, capable of high discharge rates, to power predicted laser directed energy weapons using time domain simulation is investigated in this paper. Results verify that the simulated system is capable of high rates of fire for extended periods subject to state of charge operating limitations

On the performance evaluation of lithium-ion battery systems for dynamic load functions in warship hybrid power and propulsion systems

Battery technology has developed to a juncture where high power and high energy density characteristics can be exploited for a common use battery energy storage system (ESS) for warship power systems to improve system steady state and dynamic performance. A critical review of previous research has exposed a lack of knowledge in performance assessment of battery ESS to operate as power reserve, to load level generator sets and supply laser directed energy weapons (LDEW) in a warship hybrid power and propulsion system. This research explores the performance impact of using a battery ESS in a candidate hybrid power and propulsion system. A simulation model of a lithium-ion nickel manganese cobalt based ESS was developed and validated against high rates of charge and discharge. Three system models were developed to explore the steady state, quasi-steady state and dynamic performance of the candidate power system when the battery is integrated. Three key investigations were conducted using the respective system models. The first explored the effects of ESS on the candidate power system performance when the ESS is operated as power reserve. Analysis showed that a 40% reduction in exhaust greenhouse gas (GHG) emissions was potentially achievable from the candidate warship compared to conventional operating practice. The second explored power system performance when operating the ESS operates to load level a diesel generator under quasi-steady state conditions. A 2% droop limit is suggested to mitigate against adverse quality of power supply (QPS) conditions for electrical consumers. The third investigation, and key contribution to the field of naval power systems, explored the impact of LDEW demands on the transient response of the ESS and system quality of power supply. The research findings show that the battery ESS is capable of high rates of fire for extended periods subject to state of charge operating limitations. To mitigate against adverse QPS conditions and provide operators with a realistic operating envelope to power the laser with the battery ESS, it is recommended that the power limit of the laser load should be 1.75 MW peak power

Design and Construction of a Tesla Transformer by using Microwave Oven Transfer for Experimentation

This paper has focused on the step-by-step design of a high frequency medium size (1-3 kW) air-cored resonance transformer commonly called tesla coil, that can be easily used for measurements and general research. Therefore, the task is to minimize the number of stochastic and unknown parameters influencing the device functionality and pointing out pros and cons of each solution. The physical dimension of the tesla transformer has been chosen due to cost effectiveness and availability of the regarding components. This design has mainly two units’ viz., a power supply and tesla coil. The power supply which fed the Tesla coil having voltage rating 12kV and current rating 120mA has been designed by using three microwave oven components. These components are assembled as dual MOTs voltage doubler circuit and necessary simulation has been carried out by using MicroSim Schematics for the verification of performance. Keywords:Microwave Oven , Transformer, Multi mini Capacitors, MicroSim Schematics, Toroid, Tesla Coil CAD

A relativistic magnetron-type source of nanosecond-length pulsed radiation in the 8 mm waveband

The paper describes an up-graded facility for studying performance of a high voltage pulsed magnetron of the 8 mm operation waveband. A pulse forming driving source of high output impedance is offered, yielding voltage amplitudes up to 40 kV and pulse durations about 25 ns, which provides for matching of the liquid-filled pulse forming line with the magnetron and lack of hydraulic strains. As a result, operation of the magnetron is stabilized and reproducibility of the output parameters greatly increased.Наведено результати модернізації установки для дослідження робочих режимів високовольтного імпульсного магне-трона діапазону 8 мм. Запропоноване і створене нове високоомне джерело формування імпульсів, що мають значення напруги до 40 кВ і тривалості до 25 нс. Джерело живлення, що було запропоноване, забезпечує узгодження лінії формування імпульсів з магнетроном і відзначається відсутністю гідравлічних ударів. Як результат маємо підвищення стабільності роботи магнетрона, покращення керованості режимами роботи і відтворення результатів.Представлены результаты модернизации установки для исследования рабочих режимов высоковольтного импульсного магнетрона диапазона 8 мм. Предложен и создан новый высокоомный источник формирования импульсов напряжением до 40 кВ и длительностью 25 нс, обеспечивающий согласование линии формирования импульсов с магнетроном и отсутствие в ней гидравлических ударов. В результате повышена стабильность работы магнетрона, управляемость его режимами и воспроизводимость результатов