school of electrical and electronic engineering pgr poster

School of Electrical and Electronic Engineering

PGR Poster Conference 2010

24 November 2010

The Great Hall (C1)

Sackville Street Building

Poster Abstracts

Poster Number Poster Title Poster Author

1 Efficiency of spectrum sensing in interference

environment

Abubakar U Makarfi

2 Two-stage internal model control antiwindup for

input contrained processes

Ambrose A Adegbege

3 Semantic-based image classification using

integrated features extraction methods and a

cascade of self-organising structures

Amr A Alkhuffash

4 E-waste: an overview Azadeh Dindarian

5 Realising the value of flexibility in planning of

renewable energy projects

E A Martinez Cesena

6 Decision fusion in centralized cooperative

spectrum sensing for cognitive radios

Ebtihal Gismalla

7 Characterizations and modeling of 3-D multilayer

microwave components for compact MMIC

applications

Emerson P Sinulingga

8 Power dense DC-DC convertors Frank Bryan

9 Imaging natural scenes: metamerism and the loss

in information

Gaoyang Feng

10 A non-linear approach for on-line parameter

estimation of large synchronous generators

Gustavo Valverde

11 Rare earth doped silicon based luminescent

materials for opto-electronci devices

Hang Li

12 Iterative learning controller analysis rate of

convergence analysis

Inamulhasan Shaikh

13 Transformer inrush- induced voltage dips Jinsheng Peng

14 Reinforcement learning in a self organized

representation of feature spaces

Kevin Brohan

15 A scheduling strategy for multiuser MIMO

downlink system with limited feedback and

feedback resource constraint

L Jin

16 A novel observer, Lipschitz, designed to help

identify uknown system rates

Long Ton That

17 Application of Huygens subgridding to study

defibrillation in human body

Maksims Abalenkovs

18 On improvement of accuracy of optimal voltage

sag monitoring programmes

Manuel Avendano

19 Impact of information communication

technologies on power system security

Mathaios Panteli

20 High torque density homopolar DC generator

(HDG)

Mehdi Baymani Nezhad

21 Organic electronics ingetration for RFID sensor

networks

M Shi

22 THz generation based on Gunn oscillations in

planar asymmetric nanodiodes

Mubarek Ali

23 Equivalent models for wind farms for stability

studies

Muhammed Ali

24 A novel broadband resonant structure for

negative permittivity metamaterials

Jian Zhang

25 Investigating the viability of single-pilot based

channedl estimation for OFDM systems

Muhammad Obaid Ullah

26 Dynamic analysis of squirrel cage induction

motors using coupling inductance approach

Naji Al Saiari

27 High pressure raman spectroscopy studies on

AllnGaN

Nizar A Al-Liabi

28 Physical and chemical analysis of scrapped

transformer papers

Norhafiz Azis

29 Control of industrial batch processes using NIR

spectroscopic measurements

Olufemi Osunnuyi

30 Spectroscopic conductivity of potatoes growing

within soil: with an aim to monitor growth,

health, maturation and yield in situ and

noninvasively

P A Newill

31 3D multilayer heterogeneously integrated

systems-on-chip

Peter Kyabaggu

32 Modeling and fault diagnosis of stator winding

faults of DFIGs

Qian Lu

33 The influence of interfaces and channels on

electrical tree growth in epoxy resin

R Giussani

34 Sub-soil imaging using electrical capacitance

tomography: an investigation into the use of a

mixture model for simulating the electrical

properties of soil with varying saturation levels

R R Hayes

35 Process monitoring of generation III bio-ethanol

by capillary electrophoresis techniques

Ruchi Gupta

36 Switching ferroresonant transient study using

finite element transformer model

Rui Zhang

37 Development of a novel deep brain stimulation

device and its application to focused medial

temporal lobe stimulation: construction and

initial proof of principle

Sareh Malekpour

38 Planar nanodevice operating at terahertz (THZ)

frequencies

Shahrir Kasjoo

39 Corrections on SIR theory on the study of

resonance condition of λg/4-type stepped

impedance resonators

Shokrollah Karimian

40 Mobile platforms for underwater sensor

networks

Simon A Watson

41 Robust stability and performance analysis for

uncertain linear systems – the distance measure

approach

Sonke Engelken

42 Multiphase synchronous generators for more-

electric aircraft power systems

Steven Jordan

43 Design of an adaptive small satellite for space

applications

Sunday Ekpo

44 Electro-mechanical interaction in aero gas

turbines

Tom Feehally

45 Modelling and control of variable frequency

multiphase multi-machine AC-DC power

conversion systems

Weeramundage Udaya Nuwantha Fernando

46 The numerical modeling of power transformer

cooling systems

Wei Wu

47 Study on surface discharges along the interface

between pressboard and ester liquids

Xiao Yi

48 Superconducting fault current limiter with

integrated vacuum interrupter

Xiaoze Pei

1

Efficiency of Spectrum Sensing in Interference Environment

Abubakar U. Makarfi1, Dr Khairi A. Hamdi2

MACS group, School of Electrical & Electronic Engineering, The University of Manchester

Manchester, M60 1QD, United Kingdom

[email protected], [email protected]

Abstract-The dominant radio spectrum assignment policy over the last few decades has been in favour of Fixed

Spectrum Assignment. However, this policy has been shown to encourage under-utilization of the spectrum.

Consequently, a solution is proposed to improve spectrum efficiency for unlicensed users to opportunistically access

the spectrum if non-harmful interference can be guaranteed to the primary user (licensed users). The platform to

achieve this access technology is the cognitive radio. The first and most important task of the cognitive radio is

spectrum sensing to detect exploitable areas of the spectrum for opportunistic access. An effective spectrum sensing

algorithm enables the cognitive radio to transmit without causing harmful interference to the licensed user.

However, in a multi-user environment, the aggregate interference to the sensing node may adversely affect its

sensing performance. For the purpose of this study, we define interference to include transmissions from other

unlicensed users and all other noise and transmissions in the band of interest other than the primary user’s signal.

We therefore study the efficiency of spectrum sensing in an interference environment and characterize the effect of

various factors such as power of transmission, distance and density of interferers on the overall performance of the

spectrum sensor. We further investigate the effect of adjacent channel interference on the sensing performance of

the sensing node.

2

Two-stage Internal Model Control Antiwindup for input constrained processes

Ambrose A. Adegbege

Abstract

Most physical control problems must deal with constraints imposed by equipment limitations, safety considerations

or environmental regulations. While it is often beneficial to maintain operation close to the limits in order to

maximise profit or meet stringent product specifications, the violation of actuator constraints during normal

operation can result in serious performance degradation (sometimes instability) and economic loses. In particular,

control design for processes under actuator constraints such as saturation nonlinearities has received significant

attention leading to advances in optimising control methodologies such model predictive control (MPC) and

antiwindup schemes.

Model Predictive Control algorithms are known to handle problems associated with control input saturations as the

constraints are explicitly accounted for in the control formulation. However, robust MPC design techniques increase

the controller computational burden enormously and often result in very conservative solutions or even infeasible

control problem.

We develop a simple control strategy based on the internal model control (IMC) architecture which optimises

closed-loop performance whenever the constraints are violated. Optimal transient and steady-state behaviour are

achieved through the online solution of two low-order quadratic programs (QP). The proposed method allows

operation close to the constraints and provides an intuitive tuning procedure for robustness and performance.

Simulated examples show that the proposed control design has superior performance when compared to other

existing antiwindup schemes. We consider a scenario where the proposed method competes favourably with a long

horizon model predictive control.

Affiliation:

Control System Centre,

School of Electrical and Electronic Engineering,

The University of Manchester,

M13 9PL, UK

Author’s Email: [email protected]

Supervisor: Dr. William Paul HEATH

Acknowledgment:

Financial support from Petroleum Technology Development Fund (PTDF) Nigeria is gratefully acknowledged.

3

Semantic-based Image Classification using Integrated Features Extraction Methods and a Cascade of Self-

Organising Structures

Amr A. AlKhuffash, Hujun Yin

SISP Research Group, School of Electrical and Electronic Engineering,

The University of Manchester, UK

[email protected]

Images’ classification task is still a challenging one, due to the huge amount of images that could be taken and

published, thanks to the developed and cheap imaging devices that are affordable to a wider range of people these

days.

The work that is briefly presented in this poster, studies the feasibility of forming a novel system that is inspired by

Visual Systems in Humans and other high mammalians as they were discussed in many articles that enriched the

neuroscience literature. The expected outcome is a model that’s seen as a semantic-based image classifier.

Images’ features are extracted through a platform of extraction methods that are divided into two major parts;

minimal features’ pre-processing sub-platform, and more complicated and integrated sub-platform that overlaps

with early stages of classification. The later, bears novelty potentials in the work, by giving the whole suggested

system the elasticity to classify images that depict novel objects or novel views of objects.

Hierarchical and multilayered classification models showed outperforming capabilities over flat single-layered

models, with the assumption that multilayered models gives wider classification options than hierarchical ones, such

a model –of features-extraction integrated into multilayer classifier- could give better results than some known

systems.

Some early experiments showed good results in classifying images according to their semantics, comparing with two other web-accessible systems.

4

E-Waste: an overview

Azadeh Dindarian1, Stephen Duffy2, Andrew Gibson3

School of Electrical & Electronic Engineering, The University of Manchester

Manchester, M13 9PL, United Kingdom

[email protected]; [email protected]; 3 andrew.gibson

@manchester.ac.uk;

Abstract – The rapid growth in the electronics sector and use of technology in general has inevitably resulted in the

generation of vast amounts of waste in the form of electrical and electronic equipment (WEEE). These wastes are

often highly complex, integrated and toxic and consist of valuable substances such as gold and copper. Driven by

legislation and economics the WEEE recycling industry has improved its recycling rates, reduced the environmental

impact of WEEE and increased efficiency in the recycling loop. However, a much more cost effective approach is to

re-use WEEE or its sub-assembly components.

The Microwave and Communications Research Group at the University of Manchester together with a Household

Waste Recycling Centre (HWRC) and Viridor based at South Manchester (Sharston) Recycling Centre have developed

a research program to determine the reasons why people discard electronic products and in particular microwave

ovens. The research team will be located at the local recycling centre to engage with the public and survey their

reasons for discarding WEEE and to fault-find discarded microwave ovens. The methodology will involve surveying

users of the WEEE service, collecting microwave ovens and finally fault-finding the ovens on-site.

Using surveys, fault-finding and disposal methodologies the team aim to inform the e-waste debate specifically to

work with manufacturers in order to reduce the use of hazardous materials, implement Design for Recycle (DfR)

techniques and to improve lifecycle of product and end-of-life processing, to work with recyclers in order to reduce

the cost of recycling and improve recycling processes.

1 PhD Student, MACS Group, School of Electrical and Electronic Engineering, Sackville street Building (E23), The University of

Manchester, M13 9PL, United Kingdom. 2 MACS Group, School of Electrical and Electronic Engineering, Sackville Street Building (B21), The University of Manchester, M13

9PL, United Kingdom. 3 MACS Group, School of Electrical and Electronic Engineering, Sackville Street Building (B21), The University of Manchester, M13

9PL, United Kingdom.

5

Realising the value of Flexibility in Planning of Renewable Energy Projects

E. A. Martínez Ceseña 11 and J. Mutale2



1 [email protected]; 2 [email protected]

Abstract – In the last few years, the percentage of electricity generated from Renewable Energy Sources (RES)

globally has increased. This phenomenon has been driven mainly by increasing environmental concerns, rather than

by economic reasons.

RES generation projects tend to be less economically competitive than fossil-fuel based generation projects. As a

result, RES support schemes and binding targets have had to be set in order to promote investments in RES

generation projects. However, recent studies suggest that current RES support schemes are insufficient to achieve

current green energy generation targets. Additional RES generation drivers might be needed.

This work focuses on the value of flexibility as an economic driver for RES generation projects. Flexibility can be

defined as all adjustments that can be made to a project in response to changes in its environment. In other words,

the capability of the projects managers to change the operation schedule of the generators; add, replace, or sell

generation units; accelerate or postpone investment decisions, and the like. These options can provide flexibility to a

project and increase its value. However some options would only be available if contemplated during the planning

and design of the RES generation project.

The premise of this research is to employ Real Options theory to identify and incorporate options that provide

flexibility into the planning process of RES generation projects. It is expected that the value of flexibility can enhance

the worth and competitiveness of RES generation projects.

6

Decision Fusion in Centralized Cooperative Spectrum Sensing for Cognitive Radios

Ebtihal Gismalla1, Emad Alsusa2


Manchester, M13 9PL, United Kingdom [email protected]; [email protected]

Abstract – Cognitive Radio is a new technology that exploits the underutilized frequency bands (Spectrum Holes)

through intelligent dynamic spectrum sharing. This technology aims to allow license-exempt devices, known as

cognitive radios, to opportunistically exploit licensed frequency bands. Cognitive users are supposed to sense the

location of spectrum holes and fit inside them dynamically without causing harmful interference to license-holders,

who are known as primary users. Therefore, reliable spectrum sensing schemes are essential for cognitive radio

systems. Cooperative sensing was proven in the literature to increase the probability of detecting primary users. In

addition, cooperation mitigates the hidden terminal problem which reflects the situation of a user who is visible to

the central node but invisible to other users. In this work, decision fusion rules are investigated in a centralized

spectrum sensing environment, in which all decisions from local sensing are forwarded to a common cognitive node.

The considered decision rules are Logical OR (LO), Logical AND (LA), Majority Rule (MR) and Chair-Varshney Rule

(CVR). The investigation revealed that the overall optimal rule for decision fusion is CVR. However, for high

probability of false alarm LA is also optimal, and LO is optimal for the opposite case. MR has provides an

intermediate performance between LO and LA. In terms of complexity, CVR is more complex and requires more

knowledge about the characteristics of the received signal.

7

Characterizations and Modelling of 3-D Multilayer Microwave Components for Compact MMIC

Applications

Emerson P. Sinulingga1, Prof. Ali Rezazadeh



1 [email protected]

Abstract - Improved characteristics with low dissipation loss MMICs are highly desirable for wireless communications.

This can be realized by utilizing a three-dimensional (3-D) Multilayer Coplanar Waveguide (CPW) technology. This

technology has features such as design flexibility, cost-effective fabrication and highly integration between passive

and active components. However this design has only reliable performance for compact MMICs up to operating

higher frequency of about 20 GHz. The current industrial MMIC design is mainly based on microstrip concept which

suffered from parasitics and unwanted phenomenon especially at higher frequency. On the other hand, for future

wireless technology higher frequency is required and for this on-wafer microwave characterizations and precise

modelling of 3-D Multilayer CPW components are vital.

This project concerns with the understanding of the microwave characteristics behaviour of Multilayer CPW

components in MMIC applications. It is expected to yield novel design with much improved characteristics.

Technique to de-embed parasitics from on-wafer measurement as well as suggestion of measurement approach in

higher frequency will developed. New and accurate parasitic parameter extraction using a novel Open-Short-Thru

(OST) dummies structure has also been carried out. As the result, the effect of de-embedding has shown to be

critical in removing the pads parasitic and the correct characterizations can be achieved and showed good

agreement with the analytical analysis. Feeder effect as unwanted parts in the characteristics has also been

investigated to determine its relation with half wavelength resonance. Novel feeders with lesser parasitic effect have

been proposed for future work.

8

Power Dense DC-DC Converters

Frank Bryan, Gerardo Calderon Lopez

Abstract: Electric vehicles utilise multiple energy sources for propulsion, fuel cells and batteries are energy

dense devices to provide the vehicle with a long operating range, whilst supercapacitors are power dense

to provide for the high transients during acceleration.

The output voltages of these devices vary during operation and so DC-DC converters are required to

control the energy flow between sources and provide a stable DC-link voltage. High power density is

important in automotive applications as space is limited.

Two DC-DC converters have been designed; A 100 V to 200 V bidirectional boost converter capable of 18

kW and a 190 V to 400 V bidirectional boost converter capable of 50 kW. Both converters utilise the dual

interleaved boost topology with interphase transformer which doubles the operating frequency of the

input inductor and reduces the specification of the input and output filter capacitors.

The inductor and interphase transformer are potted in aluminium heat sinks to conduct the heat to a

water cooled cold plate. Thermal finite element modelling of these components allows the designs to be

modified to reduce the hot spot temperature, allowing smaller components to be used. The converter

prototypes achieve power densities of up to 9kW/l and in excess of 6kW/kg.

9

Imaging natural scenes: metamerism

and the loss in information

Gaoyang Feng1, David H. Foster2



[email protected]; [email protected]

There are three sets of sensors in colour cameras and in the human eye which are maximally sensitive in the long-,

medium-, and short-wavelength parts of the visible spectrum. For this reason, the reflected light from a scene is

represented at each point by just three variables, conventionally labelled RGB. Because the reflectance spectra of

natural surfaces have more than three degrees of freedom, information is lost with a three-sensors representation.

The practical manifestation of this loss is the phenomenon of metamerism in which two surfaces with different

spectral reflectances have the same colour under one illuminant and a different colour under another illuminant. A

computational simulation was performed in which the number of degrees of freedom of surfaces reflectance was

varied systematically by modelling the reflectance spectra as sums of one to five randomly chosen Gaussian

functions. Shannon's mutual information between two images of a scene under different daylight illuminants was

then estimated over the synthesized scenes. It was found that the mutual information declined smoothly with

increasing the numbers of Gaussian functions, providing a quantification in bits of the impact of metamerism. The

next step in this work is to explore how many degrees of freedom are associated with natural reflectance spectra,

which will entail using principal component analysis and independent component analysis. The longer-term goal is to

understand better how imaging systems should be optimized for recording spectra from natural scenes.

10

A Non-linear Approach for On-Line Parameter Estimation of Large Synchronous Generators

Gustavo Valverde1 and Vladimir Terzija2




Abstract – Model parameters of synchronous generators may differ from those in the utility’s database due to aging

processes, magnetic saturation, and changes of temperature during machine operation. Many utilities around the

world still use the machine model parameters calculated during generator commissioning, leading to substantial

differences between the actual and simulated dynamic behaviours.

Disconnection of power plant elements for testing and model validation is neither practical nor economically

justified as it can reduce the reliability of the power system and it may increase the overall generation costs. Thus,

on-line techniques become the best option for estimating and updating models of power system plants.

This work presents an innovative non-linear parameter estimator of synchronous machines based on the Unscented

Kalman Filter (UKF). The proposed methodology uses voltages and currents taken from the stator and the field

winding to update the parameters of the classical model of the synchronous machine used in stability studies. The

Park’s Transformation is included in the estimation process to relate the stator measurements (in abc components)

with the non-linear voltage equations in qd0 reference frame. The proposed robust methodology was tested and

validated using simulated measurements collected from a large synchronous machine during transient conditions.

11

Rare earth doped Silicon based luminescent materials for opto-electronic devices

Hang Li1, Iain F. Crowe1, Amy S. Gandy1, Matthew P. Halsall1, Alan J. Harvey1,

Ursel Bangert1, Andrew P. Knights2, Russell M. Gwilliam3

1University of Manchester, UK

2McMaster University, Ontario, Canada 3University of Surrey, UK

Lead author Hang Li: [email protected]

The sensitization of rare earth metals in silicon rich oxides is being studied as a means of fabricating inexpensive,

CMOS compatible luminescent materials for optoelectronic (LED/display and lighting) device applications.

We describe preliminary spectroscopic and microscopy studies on Cerium and Europium implant doped SiO2 films

with a range of concentrations and annealing schedules. Photoluminescence (PL) and photoluminescence excitation

(PLE) was measured using a commercial Jobin Yvon spectrofluorometer and microscopy images were collected using

a Technai TEM. Low PL yield is obtained after implanting rare-earth ions to high concentrations or after annealing at

high temperatures, likely attributable to short range, ‘Auger-like’ ion-ion interactions leading to excited state

absorption, cooperative up-conversion or energy migration. This is evidenced by the presence of large (~10nm)

clusters in TEM images of samples exhibiting poor luminescence yield. We discuss a novel fabrication approach to

minimize this apparent concentration quenching.

Cerium-doped silicon oxides with cerium concentrations of up to 0.9 at. % were deposited by electron cyclotron

resonance plasma enhanced chemical vapour deposition. Bright cerium related photoluminescence, easily seen even

under room lighting conditions, was observed from the films and found to be sensitive to film composition and

annealing temperature. The film containing 0.9 at. % Ce subjected to anneal in N2 at 1200 °C for 3 h showed the

most intense cerium-related emission, easily visible under bright room lighting conditions. This is attributed to the

formation of cerium silicate _Ce2Si2O7 or Ce4.667 _SiO4_3O_, the presence of which was confirmed by high

resolution transmission electron microscopy.

12

Iterative Learning Controller

Analysis Rate of Convergence Analysis

Author: INAMULHASAN SHAIKH

[email protected]

Iterative Learning Control (ILC) is one of the Intelligent Control Systems which improves the transient performance of

systems operating in a repetitive manner. After each repetition or batch, this controller learns to produce the best

possible control input signal without changing its own configuration under certain assumptions. The current research

reviews the ILC features, algorithms and convergence conditions. Detailed convergence analysis of the first order D -

type ILC algorithm has been done; which generates the control input update for the next batch based on the

derivative of the error between the desired and actual outputs at the current batch. The point-wise relationship for

convergence rate has been formulated as ratio of infinity norms of the corresponding rows of the matrix which

controls the batch to batch evolution of control input residuals. Upper and lower bounds for the batch to batch rate

of control input residual vector have been established in terms of maximum singular value and eigenvalue of this

matrix respectively. Simulations prove that long term convergence rate of each component equals the eigenvalue of

the matrix.

13

Transformer Inrush-Induced Voltage Dips

Authors: Jinsheng Peng, Sweepeng Ang, Haiyu Li, Zhongdong. Wang

Affiliation: University of Manchester

Contact person: Jinsheng Peng

E-mail: [email protected]

Key words: Transformer, Voltage Dip, Inrush,

Summary and the contribution:

Transformer energization is a common practice in power system operation. Such an energization, without proper

assessment and control, can introduce significant inrush current. If the system about to connect the energized

transformer is weak, considerable voltage dips can also be triggered. These voltage dips are likely to violate the

tightening Grid Codes and also pose adverse impacts on sensitive loads.

Following a short review of the basic principles behind transformer inrush and sympathetic interactions, an EMTP

model has been developed for a transmission system, which allows simulations to be performed to evaluate the

impacts of energization of transformers on system voltage depression. Sympathetic inrush, which has not been

generally appreciated in terms of its prolonging effects toward voltage depression, is also discussed in this paper.

It can be concluded that the normal inrush determines the magnitude of the initial voltage sag while the sympathetic

inrush, which takes place at the latter stage, prolongs the voltage recovery process and consequently will determine

the sag duration.

14

Reinforcement Learning in a Self-Organised representation of Feature Spaces

Kevin Brohan1 ([email protected])

Alex Cope2

Kevin Gurney2

Piotr Dudek1

1 The University of Manchester

2 University of Sheffield

Abstract

We present a robotic system for biologically-inspired visual attention and action selection. The model is

implemented in the context of saccade generation in which saccades are preferentially directed towards rewarding

cues. The cues are internally represented on a self-organised map (SOM) of features. Reinforcement learning

modulates working memories of rewarding and unrewarding features in a neural layer which is topographically

mapped onto the SOM and provides top-down biasing of the visual attention. Inhibition of return and stochastic

action selection are implemented to encourage exploration of the visual world. We demonstrate that the robot

learns to associate the rewarding stimulus with the reward and that it adapts its selective attention mechanism to

adapt to a changing reward scenario.

15

A Scheduling Strategy for Multiuser MIMO Downlink System with Limited Feedback and Feedback

Resource Constraint

L. Jin1, Z. Hu2, X.Gu3



[email protected]; [email protected]; [email protected]

Abstract – A new scheduling algorithm is proposed for improving the sum-rate gain in a multiuser Multiple-Input and

Multiple-Output (MU-MIMO) downlink system with limited feedback and feedback resource constraint using Block

Diagonalization (BD) precoding. To gain the channel state information at the transmitter (CSIT) and alleviate the

feedback load for the MU-MIMO system when the channel state information is known at the receiver (CSIR), the

proposed scheduling strategy is to use a low bits feedback for user selection first and then to apply a high bits

feedback to the selected users for improving the system sum-rate capacity. Based on our analysis and the simulation

result, it shows that the newly proposed algorithm can be a potential solution to a MU-MIMO downlink system with

feedback resource constraint. A key finding is that an additional step with a high bits feedback can increase the

system capacity, especially when signal-to-noise ratio is at high value. The performance analysis for the sum-rate

gain using the proposed algorithm is presented in detail and is verified by the simulation results.

16

A novel observer, Lipschitz, designed to help identify unknown system states

Long Ton That

Univeristy of Manchester

[email protected]

Systems which have the unknown system states need observers to estimate unmeasured state variables. Models of

circadian rhythms, a class of nonlinear dynamic systems having unmeasured state variables, requires an appropriate

observer to measure the states. An observer, called Lipschitz observer, is designed to these models. In particular,

one sided Lipschitz observer is proposed to two mathematical models of circadian rhythms of Neurospora and

Mammals.

17

Application of Huygens Subgridding to Study Defibrillation in Human Body

Maksims Abalenkovs1, Fumie Costen, Jean-Pierre Bérenger2,

Ryutaro Himeno3, Masafumi Fujii4



1 [email protected], 2 [email protected], 3 [email protected], 4 [email protected]

In Europe sudden cardiac arrest causes approximately 700000 deaths per year. Electrical defibrillation is the only

effective therapy for cardiac arrest initiated by ventricular fibrillation or tachycardia. Success of defibrillation

depends on various factors: electrode shape, size, placement, defibrillator waveform, current and energy levels, and

the transthoratic impedance.

This work presents a novel computational electromagnetics algorithm HSG–FD–FDTD to study defibrillation in a

human body. This poster (i) explains the HSG–FD–FDTD algorithm and (ii) illustrates a defibrillation test case with

anteroposterior electrode placement.

18

On improvement of accuracy of Optimal Voltage Sag Monitoring Programmes

Manuel Avendaño1 and Jovica V. Milanović2



1avendano-mora @postgrad.manchester.ac.uk; 2 [email protected]

Abstract – Voltage sags (also known as voltage dips) are momentary reductions in voltage magnitude. The most

severe voltage sags are caused by short-circuits, generally associated to bad weather conditions. The main concern

posed by these disturbances is their impact on end-user equipment. Industrial processes may malfunction or shut

down due to a voltage sag, entailing considerable financial losses.

In order to assess the potential impact of voltage sags is indispensable to quantify and characterize its occurrence.

The most reliable method for determining the number and characteristics of sags is monitoring performed at all

buses in the network. However, installing a power quality (PQ) monitor on each bus of the network is technically and

economically unfeasible. Therefore, is necessary to determine the minimum number and locations of PQ monitors

required to estimate the voltage sag performance of the network.

The poster is aimed to introduce a new optimal monitor placement method for estimating the sag occurrence of the

network accurately. The proposed method calculates iteratively the sag estimation error incurred by monitor

arrangements and picks the locations with the lowest error. Since the method performs in an iterative fashion, the

accuracy of partial (sub-optimal) monitoring programs can be readily assessed and locations are automatically

ranked in terms of their contribution towards the minimization of the estimation error.

Comparison between existing and proposed methods shows the latter outperforms the present monitor location

methodologies.

19

Impact of information communication technologies on Power System Security

Mathaios Panteli1, Daniel Kirschen2



1 [email protected]; 2 [email protected]

Abstract – Due to the increased complexity of the power infrastructure, the requirement to meet a high level of

power system security has become a challenging issue. Moreover, power systems are increasingly dependent on

Information and Communication Technologies (ICT) for their secure and economical operation, under both normal

and abnormal conditions. The heavy reliance on ICT systems renders the entire infrastructure more vulnerable to

information failures and malicious attacks. This poster shows the impact of ICT systems on power system security.

The main categories of ICT systems and the effect of possible information failures on the power system state

estimation are described. A method that takes into consideration the state of the ICT infrastructure is proposed to

study the impact of ICT failures on the reliability of the electrical supply and more specifically on the probability of

catastrophic blackouts. To this end, Sequential Monte Carlo Simulations (SMCS) are developed to show the effect of

the ICT failures in terms of their contribution to load curtailment. Test results obtained using a small-scale power

system are presented.

20

High Torque Density Homopolar DC Generator (HDG)

Mehdi Baymani Nezhad

[email protected]

Abstract: Nowadays, utilisation of DC electrical machines, whether as a generator or as a motor in some sectors of

industry, are in attention of engineers more than the past. Depending upon a requirement, employment of DC

machines has some superiority over utilisation of AC machines, for example, control of DC machines are more

straightforward.

In some applications like the marine and aerospace sectors, using DC electrical networks for electrical distribution

have great advantages over AC electrical networks, for instance more VA ratings per unit volume of cable are

achievable in DC networks. With the existence of one generator that produces absolute DC voltage, it is more

convenient to connect the output of the generator directly to a DC network.

Basically, all electrical generators produce AC voltages and by means of either mechanical commutators or power

electronics, the generated voltages are converted to DC voltage but in both cases, harmonic voltages exist in the

output somewhat. The only electrical generator that can produce absolute DC voltage without using any mechanical

commutator or even power electronics is a Homopolar DC Generator (HDG). Homopolar DC Generators constructed

up to date not only are capable of producing absolute DC voltages but also the output of a HDG is high current and

low voltage and this feature may fulfil the requirement of high current and low voltage in some applications like

welding. The scope of this project is the design, simulation (using 3D-finite element software), optimisation and

construction of a novel type of HDG.

21

Organic Electronics Ingetration For RFID Sensor Networks

M. Shi1, L. Majewski2, B. Grieve3



[email protected]; [email protected]; [email protected]

The field of organic electronics holds the tremendous potential in realizing low cost large scale electronics, thanks to

the low cost polymeric materials and simple low temperature manufacturing techniques. This study investigates the

application of organic electronics for RFID sensor networks by the design of an organic capacitive measurement

circuit. The circuit is intended as the interface between passive RFID tags and a novel battery-free liquid crystal

temperature sensor. The main contribution of the study is on the design of a P-type logic comparator circuit based

on a single ended differential amplifier.

Circuits fabricated in this research use the bottom gate bottom contact fabrication process developed by Infineon.

To utilize the process, the optimal deposition conditions and patterning steps for the polymeric insulator, crosslinked

PVP (poly-4-vinylphenol), was first studied and documented. A photomask containing the configuration of single

transistors, inverters and the comparator has been designed for use with the fabrication process. Organic

semiconductors PBTTT, pentacene and PC2B1 have been tested for compatibility with the fabrication process.

Inverters and comparators have been fabricated, with a yield of 10%. Inverters achieved a gain of approximately 4 at

a supply voltage of 40V, using TIPS-pentacene. Single transistors achieved mobility of 0.0637 cm²/Vs. However,

fabricated comparators did not produce voltage curves that are in agreement with the simulated comparator data.

Future work involves the study of hybrid dielectrics using a combination of nanoparticles and polymeric insulators to

reduce the operating voltage of the organic logic circuits.

22

THz generation based on Gunn oscillations in planar asymmetric nanodiodes

Mubarak Ali1, Aimin Song2




Abstract – Applications of terahertz technology include detection of biological and chemical hazardous agents,

explosives detection, security, radio astronomy, space research and medicine. These applications have stimulated a

lot of interest in terahertz electronics technologies that have potential to replace more traditional terahertz

photonics techniques.

The most important concern in the deployment of terahertz technology is the lack of efficient and portable terahertz

radiators (emitters). Recently, self-switching devices (SSDs) have offered a neat and robust two-dimensional planar

technology that were demonstrated detection of microwave radiation up to 0.25 THz at 300K and up to 2.5 THz at

low temperature. It is envisaged that a similar device can be employed to emit electromagnetic radiation to reach

THz frequencies. Monte Carlo simulations have shown that with principles of Gunn oscillations and plasma

oscillations, frequencies up to 1 THz and 4.5 THz can be emitted respectively in planar InGaAs slot diodes.

In this work, Gunn oscillations have been observed and modelled, using the Silvaco Atlas model, in planar InGaAs

SSDs. Our simulation results support the electron dynamics within the device where the Gunn domains travel

parallel to the conduction layer, as opposed to perpendicular to the layer in traditional vertical devices. Conduction

channels of 0.5 um to 3 um in length and 60 to 120 nm in width were simulated and the radiation performance was

found to improve with decreasing lengths and increasing widths obtaining a peak radiation of 0.25 THz. Increasing

the surface charge density had remarkable improvements of reaching up to 0.5 THz.

23

Equivalent models for Wind farms for Stability Studies

Muhammad Ali1, Jovica V. Milanović2, Irinel-Sorin Ilie3, Gianfranco Chicco4



[email protected]; [email protected];


Abstract –It is vital to be able to model large wind farms accurately and quickly during transient studies of a network.

In future, when penetration of wind farms in the network increases it can pose a real challenge during on-line

stability studies due to many differential equations involved which take considerable amount of time to solve.

An innovative probabilistic clustering concept for aggregate wind turbine representation in power plant applications

is proposed in this paper. The wind turbines are first clustered based on the wind profiles at their location, creating

groups of turbines. The wind turbine clusters obtained for various wind speeds and directions are then associated to

equivalent wind generators identified from offline short-term dynamic analysis. The probability of occurrence of

each group of turbines in the clustering results is computed on the basis of the wind data referred to one year, thus

determining the most probable ones. The resulting most probable group or groups of wind generators can be used in

power system dynamics studies to model wind farms with less number of turbines. These aggregate wind turbines

can then be used as detailed wind farm equivalents for the entire year. This not only reduces the computational time

required to model several wind turbines but also avoids extra effort to aggregate turbines for every change in wind

speed and direction as proposed in the past.

Jian Zhang, and Zhirun Hu

[email protected]

Metamaterials has led to considerable interests in the electromagnetism area in the first decade of 21st century.

This is due to some of its unique electromagnetic features that may provide solutions for solving current

technological limitations. It is well known that the properties of a metamaterial are usually determined from the

geometrical structure and material parameters rather than composition. One of the problems of resonant types of

metamaterials is that they usually have narrow operating bandwidth. In this paper, a novel metamaterial resonator

with wide fractional bandwidth was proposed. This unit cell resonator is composed of two designed strips as shown

in Fig.1. These strips are copper with 0.15mm width, 0.017mm thickness, and its parameters are R1=1.97mm,

R2=1.67mm, R3=0.55mm, R4=0.25mm, d=g=0.15mm. The unit cells are laid on top of a dielectric substrate, which is

FR4 with 0.203 mm thickness.

The novel structure presented above exhibits a strong negative permittivity response at a band of 13.15GHZ to

17.93GHz, as shown in Fig. 2. The unit cell resonator was simulated using two floquet ports on master and slave

boundaries conditions by Ansoft HFSS (High Frequency Structural Simulator). The effective permittivity and

permeability of this metamaterial was extracted from simulated S-parameters S[11] and S[21]. The full wave

simulated results show that the medium constructed of a single layer of these resonators can provide a negative

permittivity band for 4.78GHz at central frequency of 15.36GHz, and its fractional bandwidth is of 31%.

Figure 1: Structure of the resonator Figure 2: Real part of permittivity

24

A Novel Broadband Resonator for Negative Permittivity Metamaterials

25

Investigating the Viability of Single-Pilot Based Channel Estimation For OFDM Systems

Muhammad Obaid Ullah 1, Dr. Emad Alsua 2.



1 [email protected]; 2 [email protected].

Orthogonal Frequency Division Multiplexing (OFDM) is very effective in combating the distortive effects of wireless

channel and promises high data rate capabilities with reasonable complexity and accuracy. Other advantages of

OFDM include significantly simple equalizer requirement, high spectral efficiency, computationally inexpensive

implementation, and increased immunity to impulse noise.

For OFDM systems, accurate and efficient channel estimation (CE) is necessary to coherently demodulate the

received data. The design complexity of CE is of crucial importance, especially for time varying channels, where it has

to be performed periodically or even continuously. Pilot-aided and blind CE techniques are common for OFDM

systems. Pilot-aided CE is more popular since it gives better results and is computationally less intensive. However,

its disadvantage is the wastage of a certain percentage of transmission bandwidth and power. Consequently, the

overall system capacity is reduced considerably.

This work is about investigating the viability of a potential candidate for CE for OFDM systems. The proposed

technique performs CE using only one pilot. Under certain channel conditions, the estimated channel frequency

response (CFR) gets inverted. If the location of inversion is found, then it is easy to rectify the estimated CFR and

reasonable BER results could be achieved. In order to find the location of inversion(s), many techniques were tried

and one based on Short-time Fourier Transform (STFT) looks promising.

Keywords

Channel Estimation (CE), OFDM, Short-time Fourier Transform (STFT).

26

Dynamic Analysis of Squirrel Cage Induction Motors using coupling inductance approach

Naji Al Saiari

[email protected]

Abstract: The project involves the development of new analytical methods of predicting the behavior of squirrel

cage induction motors subjected to pulsating load such as a compressor. The objective is to develop a design method

for determining the rating of industrial induction motors driving a pulsating load. The analytical approach used to

analyse the motor is based upon the harmonic coupling impedance method which is capable of accommodating any

stator winding arrangement used in industrial motor designs. The analytical model will be validated using software

modeling for squirrel cage induction motors driving a selection of compressor loadings. The simulation results will

finally be correlated with a detailed experimental validation in the laboratory using a test motor connected to a dc

load machine controlled electronically to simulate a compressor load.

27

High Pressure Raman Spectroscopy Studies on AlInGaN

Nizar A Al-Liabi1, Matthew P Halsall1 and Peter J Parbrook2

[email protected]

Raman spectroscopy has been studies for AlInGaN. We investigated the effect of different backscattering

configurations on the optical phonons for AlInGaN. The behaviour of the E2 and A1(LO) optical phonons of AlInGaN

under hydrostatic pressure at room temperature has been examined using Raman spectroscopy. We used Diamond

Anvil Cell DAC to generate hydrostatic pressure for up to 15GPa. We report the investigation of Raman scattering as

particularly suitable study of AlInGaN under hydrostatic pressure to determine the mode Grϋneiesn parameter �� of

A1(LO), E2(high), E1(TO) and A1(TO) phonons. We measured the shift of the TO and LO mode induced by the pressure

and determined the Mode Grüneisen Parameter �� for all modes.

1 Department of Electrical and Electronic Engineering, University of Manchester. 2 EPSRC National Centre for III-V Technologies, Department of Electronic and Electrical Engineering,

The University of Sheffield

28

Physical and chemical analysis of scrapped transformer papers

Norhafiz Azis1, Zhongdong Wang2




Abstract – Forensic investigation on scrapped transformers is well known as useful approach by power system

utilities in order to understand the “under service ageing” of transformers. It is well accepted that ageing of a

transformer could be represented by the condition of paper which is commonly assessed by its mechanical strength

and can be measured by Tensile Strength (TS).

It is reported from previous work, that the main factor for TS reduction of the aged paper is mainly due to the loss of

inter-fibre strength. The best technique that can represent the inter-fibre strength of the paper is wide span TS.

Lower Molecular Weight Acid (LMA) is reported as one of the main factors for paper degradation and it is shown that

most of these acids prefer to stay in the paper. Based on this knowledge, a new analysis was proposed by using LMA

as a chemical analysis in order to obtain more information on the ageing status of transformers.

Through the information obtain from physical (TS) and chemical (LMA) analysis, paper samples obtained from

scrapped transformers were mapped vertically across different windings and phases. Multilayer insulation effect and

relationship between TS, Degree of Polymerization (DP) and LMA also were discussed in this paper. The aim of this

paper is to understand the degradation process of “under service ageing” using both physical and chemical analysis

so that better assessment on aged transformers asset can be carried out in the future.

29

Control of Industrial Batch Processes Using NIR Spectroscopic Measurements

Olufemi Osunnuyi

Abstract

We consider the advantages of using spectroscopic measurements as feedback variables in the control of industrial

batch processes. The merits of this approach are highlighted by comparing its performance against the more widely

used implicit form of control of the quality variables. These approaches are tested on a batch reactor simulation,

where implicit control is carried out by the cascaded control of the reactor temperature and the more explicit

control is achieved by controlling the first principal component (PC) of the NIR (Near Infra Red) spectra. Results of

both forms of control in the presence of reactor rate disturbances demonstrate the edge of the proposed method

over the more traditionally applied one.

Author’s Email: [email protected]

Supervisor: Dr. Ognjen Marjanovic

Affiliation:

Control System Centre,

School of Electrical and Electronic Engineering,

The University of Manchester,

M13 9PL, UK

30

Spectroscopic Conductivity of Potatoes growing within Soil: With an aim to monitor growth, health,

maturation and yield in situ and noninvasively

P A Newill1*, R R Hayes1, F J W Podd1, T A York1, B D Grieve1

The project aims to explore the relationship and interactions between soil, water and crop roots through the use of

electrical measurement systems.

The motivation is ultimately one of supply and demand. As global population increases so too does demand for food.

Through soil, water and root relationships it is proposed that acquired data can be used to selectively breed those

with stronger genetic traits, and observe the health of crops both above and below ground. The use of in situ,

noninvasive electrical measurement systems will allow for rapid raw data acquisition of no detriment to plant health.

Variations in soil and root systems through growth and watering lead to a requirement to monitor crops over time to

offer an insight into plant wellbeing.

Lab results have shown the frequency response of potato to be such that conductivity at 1 MHz is 500% greater than

conductivity at 10 kHz. This change in conductivity provides the opportunity to perform differential frequency

measurements which create a greater contrast between soil and potato, ideal for reference imaging. Test results

have shown that this change in frequency response can be visualised through 3-D images in dedicated

reconstruction software.

Future work will concentrate on improving the accuracy of measurements of organic objects within soil. A further

aim is to utilise measurement equipment within lab space while simulating typical outdoor growing conditions. Work

will be performed predominantly on potatoes due to the mass quantities consumed worldwide, but will also include

measurements of other root vegetables.

1 SSUCI, School of Electrical and Electronic Engineering, University of Manchester, UK

* Lead Author, contact: [email protected]

31

3D MULTILAYER HETEROGENEOUSLY INTEGRATED SYSTEMS-ON-CHIP

Peter Kyabaggu1, Prof. Ali. A. Rezazadeh



1 [email protected]

Abstract - The necessary wireless communication infrastructure requires compact multifunctional microwave circuits

such as the 3D multilayer circuits. With the widespread commercial application of MMICs on system-on-a-chip (SoC)

technology, there is more pressure than ever to increase the packing density and functionality of chips. System on a

Chip (SoC) refers to the integration of all the necessary electronic circuits (MMICs) both passive and active devices

onto a single chip. Multilayer monolithic microwave integrated circuits (MMICs) structures using polyimide as

insulating dielectric layer have been utilised to demonstrate a wide range of MMICs.

This work involves designing, modelling (fabrication), simulations using Momentum in ADS and high frequency on-

wafer characterisation of the new types of circuits. The fabrication of the multilayer GaAs MMICs includes new

design structures such as CPW to microstrip transition, design of transmission lines with large impedance values,

design of an amplifier with new multilayer concepts. Fabrication techniques to realise various compact microwave

components for low cost applications will be employed to lower the cost and simplify the process. Theoretical

modelling, on-wafer high frequency measurements, thermal analysis of transmission lines using an on-chip thermal

controller and the applications of these circuits will be realised. A variety of applications of these special circuits

could be found due to their compatibility with RF systems on chip, low cost, low loss performance and their ease of

fabrication.

32

Modeling and Fault Diagnosis of Stator Winding Faults of DFIGs

Qian Lu ([email protected]) and Timofei Breikin

Abstract: The doubly fed induction generators (DFIG) have become the most widely used machines in wind power

generation. Early detection of abnormalities in DFIGs helps to reduce the down time costs and to avoid expensive

repairs. Stator winding faults are reported to be the most common electrical faults in induction machines. This paper

proposes an advanced model of DFIG. This proposed faulty model can perform the some important stator winding

fault scenarios which includes single-phase inter-turn short circuit fault, multi-phase inter-turn short circuit fault and

open circuit fault. A standard state space form of this model is derived, which provides a mathematical base for fault

detection and fault tolerance control design. Based on this state space model, an observer based fault diagnosis

strategy is proposed. This new strategy can not only locate the fault position but also determine the fault level. An

exponential adaptive observer is applied in this strategy which can provide a desirable estimation of the fault level.

In order to enhance the observer robustness, three different methods of designing the observer feedback gain are

implemented respectively, and their performances are compared. The simulation results demonstrate that this

observer based approach has effectiveness on fault diagnosis under both steady state operation and transient state

operation. It has strong robustness against the speed and load variations. This advantage has significance on fault

diagnosis of wind turbine DFIGs, since the DFIGs are predominantly under varying speed operation.

33

The Influence of Interfaces and Channels on Electrical Tree Growth in Epoxy Resin

R. Giussani 1, S. Bahadoorsingh 2 and S. M. Rowland3

The University of Manchester, School of Electrical and Electronic Engineering


E-mail: [email protected]

Abstract – Electrical treeing is an extensively studied electrical ageing mechanism. Electrical tree growth in the

presence of voids, barriers, interfaces and channels as well as other artificially induced defects have been the focal

point of many investigations. At the same time it is becoming widely acknowledged that in practical power systems,

material interfaces (for example in cable joints) often control the reliability of such systems rather than bulk

materials (for example within cable lengths).

This experimental study sought to investigate the influence of epoxy resin interfaces and ventilated channels on

electrical tree growth. The electrical trees were developed in pin-plane geometry using 3 μm radius hypodermic

needles and 2 mm gap in epoxy resin (LY/HY 5052) samples and tested in the voltage range of 6-15 kV rms. The

diameter of the ventilated channels were varied (0.16 mm < diameter < 0.30 mm). The distance to the grounded

plane of both the epoxy resin interface and the ventilated channels were also varied (0.5 mm< distance <1.5 mm).

The results suggest an increased time to electrical breakdown when the location of the interface is equidistant of the

insulation gap. Digitally captured images depict electrical tree growth features and a very narrow breakdown track is

identified when the interface layer is non-conducting.

34

Sub-soil imaging using Electrical Capacitance Tomography: An investigation into the use of a mixture

model for simulating the electrical properties of soil with varying saturation levels

R R Hayes, P A Newill, F J W Podd, O Dorn, T A York, B D Grieve

In light of climatic change, rapid identification of new plant varieties that will thrive in future climates is increasingly

important. The root system is critical to plant water uptake but this cannot easily be assessed without destroying the

crop or disturbing the plant/soil matrix through extractive sampling.

We are developing a new visualisation tool for seed breeders, providing on-line data of individual plants in a

screening programme. It will indicate how efficiently each plant utilises the water available in the surrounding soil.

This will facilitate early detection of desirable genetic traits.

Visualisation takes the form of Electrical Capacitance Tomography (ECT), a non-destructive and non-intrusive

imaging technique. Measurements are to be obtained for individual plants thus allowing water absorption levels for

each specimen to be inferred.

An investigation into the relationship between soil moisture content and the soils dielectric permittivity has been

carried out. A mixture model was implemented which permits the estimation of electrical capacitance measurement

data for varying soil saturation levels. Experiments have shown that the finite element model (FEM) electrostatics

simulation is accurate (error < 9%).

These early studies stand as a proof-of-concept and have given the research team an understanding of the technical

challenges that must now be addressed to take the current instrumentation into the food supply sector.

35

Process Monitoring of Generation III Bio-ethanol by Capillary Electrophoresis Techniques

Ruchi Gupta*1, Peter R. Fielden

2 and Bruce D. Grieve

1

[email protected]

1

Syngenta Sensors and ICT University Innovation Centre, School of Electrical and Electronic Engineering, University of

Manchester, Manchester, UK 2 School of Chemical Engineering and Analytical Science, University of Manchester, Manchester, UK

The conversion of waste genetically modified (GM) enzyme-expressing sugarcane stalks to bio-ethanol (generation III)

has the potential to reduce our dependence on petroleum resources. However, variability in the concentration of

the expressed enzymes [cellobiohydrolase (CBH), endoglucanase (EG) and β-glucosidase (BG)] makes assessment of

their composition in every batch of harvested sugarcane essential for quality control of the bio-ethanol process.

Enzyme activity assays and enzyme-linked immunosorbent assays (ELISA) are not suitable to quantify these enzymes

in factories due to their non-specificity and laborious nature respectively. We have investigated the feasibility of

capillary zone electrophoresis (CZE) for the purpose due to its high resolution and amenability to automation. But

major challenges in using CZE are the reduction in its separation efficiency due to presence of large amounts of salts

and organic or inorganic acids, as well as unpredictable shifts in migration time due to undesirable proteins.

Therefore, initially the use of membrane filtration was investigated for the removal of interfering sample

components.

The use of CZE in a 15 mM, pH 7.75 phosphate buffer resulted in separation and quantification of CBH, EG and BG

within 10 min. Migration time reproducibility was between 0.56 and 0.7% and hence suitable for use with automatic

peak detection software. Furthermore, the limit of detection of the developed method was suitable to monitor the

expected concentration of enzymes in GM sugarcane juice.

Although sample preparation via filtration was suitable in a laboratory environment, membrane fouling and

blockages continue to be a serious design and operational concern in juice purification. Hence, we have designed an

isotachophoretic (ITP) electrolyte system and a simple front cutting method for sample clean-up due to the

techniques’ lower vulnerability to system blockages and ease of on-line integration with CZE. Finally, the

effectiveness of ITP vs. filtration for the purpose has been compared.

36

Switching Ferroresonant Transient Study using Finite Element Transformer model

Rui Zhang1, Haiyu Li2, Zhongdong Wang3



[email protected]; [email protected]; [email protected];

Abstract

Distribution network asset replacement program has been recently carried out in an increasing volume across the

Europe, due to the fact that network infrastructures are ageing and reinforcing the aged infrastructure is becoming a

necessity to ensure the reliable supply of electricity. Combining with reinvestment, changes are also made on power

system/substation design in terms of taking advantage of technology development or fitting into new regulations. As

an example, cables instead of overhead lines are nowadays more frequently used to reduce environmental/visual

impacts; old types of circuit breakers are replaced with new SF6 technologies and new less loss transformer

lamination material are being used. These changes bring new technical challenges when one considers the transient

phenomena during switching operations or system short circuit faults. Under such a change of system configuration,

a new combination of inductive and capacitive network is formed which may result in harmful overvoltage,

overcurrent or/and overflux occurring to equipment. The quite important and costly part in distribution system is

transformers.

This poster aim to represent following two methods for transient study: firstly certain transient phenomena effects

on distribution network, using ATP-Draw build an accurate model and try to understand each component influence

transient results, such as circuit breaker grading capacitor and opening time, cable capacitor and transformer core

characteristics; secondly focus on transformer using FEM build an accurate transformer model to understand when

ferroresonance and inrush transient phenomena occur how is flux density, magnetic field and power loss going on

inside of transformer and how would be damage or influence insulation ageing.

37

Development of a novel deep brain stimulation device and its application to focused medial temporal

lobe stimulation: Construction and initial proof of principle

Sareh Malekpour1, Prof. Andrew Mayes2, Dr. Daniela Montaldi3 and Prof. Zhipeng Wu4


Manchester, M60 1QD, United Kingdom [email protected], [email protected],

[email protected], 4 [email protected]

The aim of cognitive neuroscience is to discover the neural bases of all kinds of cognition. This can be done by

studying the effect of lesions on specific brain structures in humans or animals. This has led to the development of

techniques that produce reversible disruptions of function in local brain regions. The two methods that are currently

available are Deep Brain Stimulation (DBS) and Transcranial Magnetic Stimulation (TMS). The former method is

invasive and the latter cannot disrupt deep brain structure in a focused way.

The current research aims to construct and optimize a safe and relatively noninvasive device which produces a

sufficient focused stimulation using RF waves so that focused, reversible disruption can be generated in deep-lying

brain structures. This device focuses low-frequency modulated stimulation from transmitter-receiver electrodes

placed around the human head to produce reversible disruption at any location within the brain. The function of this

device will be tested and enhanced utilizing simulation and phantom-based investigation. Identifying the factors that

determine the stimulation locality, extent and strength is the next research target.

The frequency of the stimulation is of prime importance for this research study. High frequencies do not penetrate

to sufficient depth; however, low frequencies can penetrate much further. However, it is much easier to focus

energy using high, rather than low, frequencies. Therefore, there needs to be a trade-off between the focusing and

penetration abilities of high and low frequencies.

38

PLANAR NANODEVICE OPERATING AT TERAHERTZ (THZ) FREQUENCIES

Authors: - Shahrir Kasjoo, Aimin Song

University of Manchester

Here we report on the TeraHertz (THz) operation of a planar nanodevices based on an asymmetric nanochannel, also

known as self-switching device (SSD), which is fabricated on a high-mobility two-dimensional electron gas (2DEG)

embedded in AlGaAs/GaAs heterostructure. This novel nanodevice coupled with a micro bow-tie antenna has been

successfully demonstrated to detect 1.5 THz radiation generated by free electron laser at room temperature; this is

to the author’s knowledge, the fastest electronic nanodevice at room temperature reported to date. The estimated

voltage sensitivity achieved was 1.37 mV/mW. The fabrication process of SSDs is simpler and cheaper than

conventional detection devices; hence SSD-based technology is a promising candidate for future high operation

speed of electronic devices.

39

Corrections on SIR theory on the Study of Resonance Condition of λg/4-type Stepped

Impedance Resonators

Shokrollah Karimian and Zhirun Hu

Microwave and Communication Systems (MACS), School of EEE

The University of Manchester, PO Box 88, M60 1QD

[email protected]

Abstract

Stepped-impedance resonators (SIRs) are one of the best candidates for planar filter design

using resonators [1-3]. This is due to their capability of reducing resonator size without

degradation of the unloaded-Q [4], as well as their ability of controlling spurious frequencies

by design [5]. Although the theory to SIRs is well-provided, there seems to be a

misinterpretation in the analysis of fundamental element of SIRs [6], i.e. the Quarterwavelength-

type SIR, originated from [7].

In this paper, the authors identify and highlight this issue and provide the correct analysis

towards study of the λg/4-tpye SIR. The analysis is validated using three techniques of (i)

numerical calculations, (ii) RLC lumped-element equivalent resonant circuit model, and (iii)

full-wave 3D electromagnetic simulations.

Keywords: Stepped impedance resonator, planar filter, quarter-wavelength, SIR analysis.

References

[1] M. Makimoto, and S. Yamashita, “Compact bandpass filters using stepped impendence resonators,”

Proc. IEEE, vol.67, 1979, pp. 16-19.

[2] U.Y. Kongpop, E.J. Wollack, T.A. Doiron, J. Papapolymerou and J. Laskar, “A planar bandpass filter

design with wide stopband using double split-end stepped-impedance resonators,” IEEE Transactions

on Microwave Theory And Techniques, Vol. 54, No. 3, March 2006, pp. 1237-1244.

[3] M. Makimoto, and S. Yamashita, “Bandpass filters using parallel coupled stripline stepped impedance

resonators,” IEEE Trans. Microwave Theory Tech., vol. MTT–28, Dec. 1980, pp. 1413-1417.

[4] P.K. Singh, S. Basu and Y.H. Wang, “Miniature Dual-Band Filter Using Quarter Wavelength Stepped

Impedance Resonators,” IEEE Microwave and Wireless Components Letters, Vol. 18, No. 2, February

2008, pp. 88-90.

[5] J.T. Kuo and E. Shih, “Microstrip stepped impedance resonator bandpass filter with an extended

optimal rejection bandwidth,” IEEE Transactions on Microwave Theory and Techniques, Vol. 51, No.

5, May 2003, pp. 1554-1559.

[6] J.K. Xiao, S.W. Ma and Y. Li, “A Compact Microstrip Stepped-impedance Resonator and Filter,”

Microwave Journal, Vol. 50, No. 2, February 2007, p. 116.

[7] M. Makimoto, S. Yamashita, Microwave Resonators and Filters for Wireless Communication –

Theory, Design and Application, Springer, 2001, pp. 11-19.

40

Mobile Platforms for Underwater Sensor Networks

Simon A. Watson1, Peter N. Green2




Abstract – The research project is part of a larger collaboration entitled AASN4IP (Actuated Acoustic Sensor

Networks for Industrial Processes) whose aim is to design generic wireless sensing network technologies for use in

aqueous-based industrial processes. The demonstrator for the project will be a ‘swarm’ of mobile nodes which can

map the bottom of a nuclear storage pond.

The objective of the research project is to develop an underwater mobile instrumentation platform (or node) in the

form of a micro-autonomous underwater vehicle (μAUV), able to move to any 3D position in a controlled manner.

The main tasks are to design the hull and propulsion systems, to develop suitable low level control algorithms for

them which can be interfaced to higher level navigation and obstacle detection sub-systems and to develop suitable

re-chargeable power systems.

All aspects of the node design are being developed from scratch, however off-the-shelf components are being used

as much as possible. To date, the hull and propulsion systems have been designed along with control circuitry and

basic low-level control algorithms. Several prototype systems have been built and tested.

Once the system hardware has been fully designed and tested, other aspects of the AASN4IP project will be

integrated into it, such as the acoustic communication and positioning system, measurement sensors and

exploration algorithms. The project is currently at the stage of developing and testing multi-degree of freedom

prototype nodes along with the relevant low-level control algorithms.

41

Robust stability and performance analysis for uncertain

linear systems—The distance measure approach

Sönke Engelken, Alexander Lanzon, Sourav Patra, and George Papageorgiou,

This poster presents readily applicable distance measures, robust stability margins and associated robust stability

and robust performance theorems for three commonly used uncertainty structures (additive, input/output

multiplicative, output/input inverse multiplicative). Besides providing robust stability results for a larger uncertainty

class than previously reported (RL∞ instead of RH∞), this poster also states robust performance theorems for the

above uncertainty structures. The theorems on this poster enable practising engineers to choose the most suitable

uncertainty structure for a family of uncertain plants, as illustrated through a physically motivated numerical

example.

S. Engelken, A. Lanzon and S. Patra are with the School of Electrical and Electronic Engineering, University of

Manchester, Sackville Street, Manchester, M60 1QD, UK. G. Papageorgiou is with Honeywell Aerospace Advanced

Technology Europe, 4, Avenue Saint Granier, 31024 Toulouse, France.

Lead author: S. Engelken, [email protected]

42

Multiphase Synchronous Generators for More-Electric Aircraft Power Systems

Steven Jordan

[email protected]

Abstract: More-electric aircraft systems are, at present, the focus of considerable development within the aerospace

sector. As a result of airframe capacity increasing, the amount of electrical energy required for flight controls, critical

navigation equipment, in-flight entertainment and auxiliary loads, has increased greatly in the past decade.

This project is concerned with investigating a novel generation technique to meet the future power demands of

more-electric aircraft systems; replacing the current variable frequency generator found on the Trent 1000 aero-

engine. A multiphase synchronous generator can provide the increased power requirement whilst maintaining the

system integrity required for civil aerospace; the increase in the number of phases providing redundancy in the

event of a fault. Rectification, via a power electronic converter, eliminates the variation in system frequency and the

multiphase aspect allows for the potential removal of the filter capacitance on the DC side; highly beneficial from a

safety perspective.

Analysis has been carried out on a mathematical model developed to simulate a synchronous generator using 3-

phase architecture. The simulation has been compared to a standard software package model as well as laboratory

testing. The validation of the mathematical model has led to the development of a multiphase model, including a

power electronic converter stage and DC bus power system with associated loads. Future work will include the

simulation of a controlled power electronic converter leading on to its development and fabrication before

interfacing with a multiphase synchronous generator for full system testing.

43

Design of an Adaptive Small Satellite for Space Applications

Sunday Ekpo1, Dr Danielle George2




Abstract – Present and future small satellite missions require adaptive, reliable and cost-effective infrastructure and

operations to support the ever-expanding multimedia/broadband applications. This paper presents a design

approach that leverages on the existing advances in small satellite subsubsystem, subsystem and system-levels

technologies and architectures including field programmable gate array, monolithic microwave integrated circuits,

scaling strategies, system-on-a-chip, active electronically scanned array and reconfigurable multifunctional

architecture.

The developed small satellite design model enables five design customizations of various satellite systems using

adaptive functional modules that implement higher-level customized and reconfigurable space mission capabilities.

Each adaptive multifunctional unit performs the subsystem capabilities as a “structural and functional block” with

recourse to either baseline or hybrid configurations. In this way, the conventional subsystem boundaries are

eliminated. Furthermore, power budget model, broadband receiver subsubsystem design and experimental

modelling procedure have been developed for the implementation of the highly adaptive small satellite architecture

system. Analysis involving the satellite design lifetime reveals that future satellites designed with the presented

adaptive functional concept will have the potential to triple the lifecycle of conventional satellites with advanced

mission capabilities.

The preliminary results of the adaptive small satellite design shown in this paper span communication,

meteorological and planetary missions. Possible satellite transitions are also stated and the associated capabilities

and applications explored.

The obvious benefits of this novel small satellite design concept includes adaptive, reconfigurable and

multifunctional architectures with cost savings and economies of scale, timely launch, dynamic redundancy, system-

level reliability, emergent capabilities support and optimal performance at the desired mission objectives.

44

Electro-Mechanical Interaction in Aero Gas Turbines

Tom Feehally

[email protected]

Abstract: The traditional aircraft engine has predominantly been concerned with providing thrust to propel the

aircraft. Increasingly, however, modern aircraft engines are also required to provide substantial electrical power.

This energy is extracted mechanically from the rotating spools of the gas turbine before being transferred through an

extensive torsional network of driveshafts and gears to drive the electrical generators. As weight is critical to aircraft

performance, these mechanical systems are designed with minimal material mass. This makes them light-weight but

also highly vulnerable to fatigue.

The aircrafts electrical network supports a wide variety of loads, which may be high powered and/or introduce high

frequency disturbances to the network. Loading on the electrical network is transferred through the generator as

torque loading on the mechanical network. Hence variable electrical loads have the potential to excite resonances

within the mechanical systems, increasing the likelihood of their failure. Electrical and mechanical systems can no

longer be thought of separately, instead a combined electro-mechanical network with distinct behaviour must be

considered.

This project investigates the issues of electro-mechanical interaction in aero gas turbines; predicting interactions and

developing strategies for their suppression through control schemes and mechanical design. These strategies include

the use of a novel wound-rotor generator, allowing more flexible control at the interface between the domains, and

the formation of designs for the mechanical system which reduce vulnerability without altering performance.

Simulation work has been validated against real engine test data and an adaptable test rig is being developed in

order to further studies.

45

Modelling and control of variable frequency multiphase multi-machine AC-DC power conversion systems.

Weeramundage Udaya Nuwantha Fernando, Dr. M. Barnes, Dr. O. Marjanovic

[email protected]

Abstract: Modelling and control of multiphase AC-DC power conversion systems is considered. The mathematical

model of a system comprising of multiple Permanent Magnet Generators (PMGs) and active rectifier systems is

developed. The control objectives of DC link voltage stabilization minimized reactive power transfer and dynamic

load sharing issues are addressed. The system transient load sharing is achieved by matching the controller gain

values with the load sharing requirements. Methods of steady state load sharing viz. automatic master-slave control

and droop based load sharing are developed for the application of parallel PMG and rectifier systems. A droop

regulation scheme for DC link voltage control is proposed. The properties of each method are discussed. Simulation

results are presented for a system with five fault tolerant multiphase PMG fed active rectifier units. The system is

subjected to a severe loading step demand and the DC link voltage and the load sharing characteristics are analysed.

46

The Numerical Modelling of Power

Transformer Cooling Systems

Wei Wu1, Prof Zhongdong Wang2




Abstract – In the context of transformer thermal performance and end-of-life criteria, the accurate prediction of the

magnitude and location of the maximum temperature or ‘Hot-spot’ inside a transformer is of great importance.

Various types of calculation approaches have been developed in the attempt to gain an accurate prediction of the

hot-spot, one of which can be generally classified as ‘network models’. In network modelling methodology, the

complex pattern of cooling oil ducts and passes inside a winding is reduced to a matrix of simple hydraulic channel

approximations, where empirical analytical expressions are employed to hydraulically and thermally express oil flow

and heat transfer. Based on the implementation of network modelling, TEFLOW developed by CEGB, UK in the late

1980's, this PhD research aims to review, evaluate and improve the currently used ‘off-the-shelf’ mathematic

expressions in network models. COMSOL multiphysics software package for Computational Fluid Dynamics (CFD),

which offers a higher order of accuracy relative to network models, and sensitivity studies are applied to achieve

these objectives.

47

Study on surface discharges along the interface between pressboard and ester liquids

Xiao Yi1, Zhongdong Wang2




Abstract –Experimental study is conducted on patterns of creepage discharge on pressboard surface in divergent

electric field under AC stress. With the help of high speed image recorder, wideband sampling resistor and

commercial PD detector, the difference in discharge patterns between open oil gap and on pressboard surface is

studied and the creepage discharge behaviors of mineral oil and esters are compared. The presence of pressboard

surface tends to promote the negative discharges and enables discharges to occur at smaller phase angles. The

effect of pressboard surface on discharge pattern might be caused by surface charging and bubble residence. Due to

higher discharge intensity and larger viscosity, this effect is much more obvious in esters.

48

Superconducting Fault Current Limiter with Integrated Vacuum Interrupter

Xiaoze Pei

[email protected]

Abstract: Fault current levels in traditional land-based distribution and autonomous electrical power systems used in

marine or aerospace applications are of increasing concern. In land-based systems, fault current levels are rising

generally but this is being compounded by the increasing capacity of connected distributed generation. Increasing

fault levels will require expensive network investment in upgrading equipment such as circuit breakers and

transformers. There is a growing need therefore for current limiting devices to be embedded into modern electrical

networks to avoid a large-scale and expensive upgrading of existing switchgear.

A resistive fault current limiter made of MgB2 superconducting wire has been prototyped under a Rolls-Royce led

project at Manchester and demonstrated effective and repeatable fault current limiting.

The main disadvantage is that once the superconducting wire quenches it heats up very rapidly and takes many

minutes to recover once the fault has been cleared. The purpose of this research is to explore the potential for

integrating a vacuum interrupter into the vacuum within the cryostat unit directly. A resistor could then be

connected in parallel but external to the cryostat to act as the fault limiting resistance once the interrupter has

opened. The unit would still operate automatically but the fault current can now be quickly diverted from the

superconducting coil before it begins to heat up, significantly reducing the recovery time of the unit.

The first prototype SFCL with integrated vacuum interrupter demonstrated successful operation. Once a fault

happens, a fast actuator opens vacuum interrupter before the next current zero crossing. Therefore, the heat up and

recovery time has been reduced dramatically.

school of electrical and electronic engineering pgr poster

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