A5030486210- Electric Motor Design and Analysis
- Magnetic Properties and Applications
- Magnetic Bearings and Levitation Dynamics
- HVDC Systems and Fault Protection
- Machine Fault Diagnosis Techniques
- Particle Accelerators and Free-Electron Lasers
- Physics of Superconductivity and Magnetism
- Sensorless Control of Electric Motors
- Induction Heating and Inverter Technology
- Particle accelerators and beam dynamics
- Superconductivity in MgB2 and Alloys
- Wind Turbine Control Systems
- Non-Destructive Testing Techniques
- Multilevel Inverters and Converters
- Particle Detector Development and Performance
- Superconducting Materials and Applications
- Silicon Carbide Semiconductor Technologies
- High voltage insulation and dielectric phenomena
- Advanced DC-DC Converters
- Electromagnetic Launch and Propulsion Technology
- Plasma Diagnostics and Applications
- Wireless Power Transfer Systems
- High-Voltage Power Transmission Systems
- Crystallization and Solubility Studies
- Oil and Gas Production Techniques
Oregon Health & Science University
2024-2025
University of Manchester
2016-2025
University of Portland
2024
Imperial College London
1988-2024
Verizon (United States)
2020
Newcastle University
2016-2019
SLAC National Accelerator Laboratory
2002-2019
University of Bath
2019
University of Cumbria
2014
Singapore Institute of Manufacturing Technology
2012
In this paper, the authors take a high-level look at multiphase induction machines in order to examine those aspects that are not design specific. They show for machine which only variable is phase number, main target loss reduction stator copper loss, by use of more than three phases may be attenuate as much 8.5%. addition, general expression harmonic fields produced when having any number excited from PWM inverter derived, and sources torque pulsation identified.
The paper describes an analytical model for cage induction motors with a static eccentric rotor. method is based on airgap permeance approach including stator and rotor MMF harmonics. windings are resolved into harmonic conductor density distributions that allow different series/parallel winding connections to be accommodated in straightforward manner. Sinusoidal homopolar field components identified the total distribution used determine radial forces examines principal interactions...
HVDC circuit breakers are of increasing importance, as multi-terminal high voltage DC (HVDC) transmission becomes a commercial reality. Multiple breaker technologies have been developed, and starting to appear proof-of-concept installations on real networks. Information about them is however distributed widely in the literature. This article describes underlying challenges, leading candidate solutions, discusses requirements construction component sub-assemblies. Its goal provide...
An analysis is developed for 3-phase induction motors with any distribution and number of rotorbar end-ring failures. The method verified, using an inverted-geometry cage motor on which careful measurements rotor-bar currents are made. then used to investigate a fault 250 hp, 8-pole, 60 Hz motor.
An analytical and experimental comparison of the performance multiphase induction machines as a function number phases is provided. The method generalised complex harmonic analysis used to model machine, including calculation pulsating torques. This general validated with results. test machine standard motor frame, which had been modified bring every coil out patch panel. With 12 coils per pole, was tested in 3, 4, 6 12-phase operation. Results show moderate reductions stator losses...
<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Integrated full electric propulsion systems are being introduced across both civil and military marine sectors. Standard power system analysis packages cover electrical electromagnetic components but have limited models of mechanical subsystems their controllers. Hence, electromechanical interactions between the prime movers, network, driven loads poorly understood. This paper reviews available...
This study investigates the condition monitoring of wind turbine wound rotor and doubly fed induction generators with electrical asymmetries by analysis stator current total power spectra. The research is verified using experimental data measured on two different test rigs numerical predictions obtained from a time-stepping electromagnetic model. A steady-state spectra for healthy faulty conditions performed to identify fault-specific signal changes consistent slip-dependent fault-indicators...
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Direct current (DC) circuit breakers are a key enabling technology for fault management in multiterminal high-voltage DC (HVDC) systems. isolation is challenging due to the high rate of rise and lack natural zero-crossings found ac In this paper, we present novel superconducting hybrid dc breaker that utilizes intrinsic characteristics superconductor material. The automatic quench coil as result transfers from mechanical switch semiconductor switch. isolating able therefore open at low...
High-voltage direct current (HVDC) transmission systems using Voltage-Source Converters (VSC) are widely recognized as offering significant potential for long distance high power delivery, particularly offshore wind farm connections. One of the barriers development multi-terminal HVDC is lack technologies which enable fault isolation. This paper will investigate DC limiting technology to reduce currents acceptable levels allowing circuit breakers operate quickly and reliably. Superconducting...
Genomic instability is a hallmark of cancer, driving oncogenic mutations that enhance tumor aggressiveness and drug resistance. MYC, master transcription factor deregulated in nearly all human tumors, paradoxically induces replication stress associated DNA damage while also increasing expression repair factors mediating resistance to DNA-damaging therapies. Emerging evidence supports non-transcriptional role for MYC preserving genomic integrity at sites active protecting stalled forks under...
We present an assessment of the effect rotational losses on induction machine. The provides estimate iron in machine by three methods, all which rely output data a two-dimensional finite-element method: 1) calculating as if they were produced purely alternating field; 2) adding orthogonal components flux density, these independent phenomena; 3) applying correction factor based experimental to improve loss calculation. is function peak density value and ratio major minor axis loci. third...
Transient cage induction motor models for use in inverter-fed drives and controllers are reviewed. A simple transient model is presented that includes rotor deep bar effect magnetic saturation of the magnetising leakage flux paths. The improved requires details form impedance versus frequency characteristics which can be obtained from a variety external sources. These range typically detailed steady-state finite-element solutions to experimental measurements. verified experimentally using 75...
The paper describes an experimental investigation into the behaviour of a cage induction motor with statically eccentric rotor. equipment used allowed for variation eccentricity and direct measurement unbalanced magnetic pull. effects parallel connections stator windings damping nature rotor are investigated. results to verify accuracy analytical model derived elsewhere correlation between measured predicted UMP is found be good.
Hybrid electric propulsion has been identified as a potential solution to the ambitious environmental emissions and noise targets of aerospace industry. Superconducting machines may be key component that topology enabling high power densities efficiencies needed in aerospace. Fully superconducting machines, however, are not mature technology. This paper looks at different machine design configurations focusing on stator magnetic circuit fully motor. The motor designed for an distributed fan...
This paper presents a general analytical method for determining the unbalanced magnetic pull (UMP) produced in three-phase induction motors with an eccentric rotor. The model uses conformal transformation technique coupled to winding impedance approach that is capable of accommodating any stator connection. examines influence using parallel paths as means reducing resultant UMP (static and pulsating). results clearly demonstrate significant reduction static typical together currents are...
There is currently significant interest in offshore wind turbines up to 5 MW. One of the preferred options doubly fed slip-ring generators. Turbine manufacturers have proposed an operating scheme for low speeds that claimed improve overall energy extraction from wind. This paper aims examine performance benefits this new operational mode on a small experimental rig, confirmed by simulation, and provide fundamental understanding differences generator operation both modes. develops analytical...
This paper investigates the spectral effects that stator supply harmonics can induce in wound rotor and doubly-fed induction generators. The purpose of this study is to clarify nature origin reported significant inter harmonic these machines. To end, authors derive analytical expressions define signature frequencies individual current torque signals. are first validated through comparison with spectra calculated using a time-stepped machine model then by measurements on laboratory test rig...
A method for the analysis of induction motor transients using two-dimensional finite-element is described. Unlike previously published work does not use an eddy-current formulation to account currents induced in rotor bars. It relies on decomposition into harmonic distributions and auxiliary circuit equations take time-stepping account. The adoption this technique yields some distinct advantages. Firstly, limited model alone, thereby allowing optimum step size be selected at all times....
The transmission requirements of the next generation offshore wind farms, such as Round Two U.K. development proposals, may rely on high-voltage direct current (HVDC) technology for at least a part their power collection and requirements. HVDC is particularly suited high powers through large lengths submarine cables; however, its application limited by cost ac-dc converter stations. This paper therefore investigates feasibility using novel generator topology, an alternative solution to...
Improving offshore wind turbine reliability is a key industry goal to improve the availability of this renewable energy generation source. The semiconductor devices in power converter are traditionally considered as most sensitive and important components achieve managing their thermomechanical stressing vital, since one principal long-term aging mechanisms. Conventional deterministic prediction methods used industrial applications not suitable for applications, due stochastic nature speed....