PhD student Nils van der Blij was featured on the December issue of the Quadraad magazine. The article has been seen at this link
Title: A study to end-winding induced iron losses in high-speed electrical machines with concentrated windings
Venue: Van der Poelzaal , LB01.220 at 15.00 hrs
One potential problem associated with the high electrical frequency in high-speed electrical machines are additional iron losses near the end-windings. They are expected to be a significant part of the total iron loss. The reader is introduced to currently known methods to study high-frequency iron loss estimation and end-effects in laminated media. No suitable method is found. Therefore, an experimental approach is presented. A short-axial laminated stator core is exposed to high-frequency excitation fields generated by coils with normal and extended end-winding heights. The proposed experimental method is verified numerically with a simplified brute-force 3D finite element model. Significant less losses are measured and calculated for the extended end-winding case. The results show that most of the high-frequency losses are induced in the stator end laminations near the end-winding. In addition, it is found that the traditional eddy-current model underestimates the modelled results significantly if a wrong peak magnetic flux density is used. With both the experimental and numerical approach, it is shown that the impact of high-frequency end-winding induced iron losses on the total core loss cannot be neglected in iron loss estimation methods for short axial high-speed electrical machines with concentrated windings.
Title: Sustainable & Contactless Charging of e-Bikes
Venue: Snijderszaal, LB01.010 at 10.00 hrs
E-Bikes are considered to be a green form of transportation, but if the main source of energy to charge the bikes still comes from fossil fuels is the e-bike still called green?In this thesis a sustainable bike shed is designed with the aim to be grid independent. Also the way of charging the e-bikes is not user friendly because the user has to bring their charger with them. A solution for this is the second part of the thesis, a contactless charging system for e-bikes is designed.
The annual Christmas dinner of the DCE&S group was held in the Indian restaurant 'Maharaja' with the theme 'India' on 13th December 2016. Indian attire was worn by the members of the group and there was a presentation by the Indian PhD students on Indian culture and traditions. It is planned to have every Christmas dinner based on the theme of a country.
The annual apple prize of the department of Electrical Sustainable Energy was given to PhD student Gautham Ram Chandra Mouli on the occasion of the annual Christmas dinner of the department on 20th December 2016. The prize was a Slovakian glass souvenir shaped like an apple.
Title: Condition assessment of water in high viscosity insulating Cable termination oil
Venue: Van Katwijkzaal, HB03.240 at 14.00 hrs
High voltage termination is contained within a bushing that is filled with insulating cable oil. The insulating cable oil is a containment medium for the electric field lines and should have low dielectric losses, chemical inertness against the construction material, non-flammability and stable electrical property during prolong heating. The initial stages of the thesis seeks to inventory water polluting oil. Studies will be done into the influence of water particles on the electrical performance of the oil. Finally the thesis would look to find mitigation techniques integrating the given inventories and observations, so as to formulate non-intrusive diagnostic methods to ascertain polluted terminations.
Title: Design and Development of a 72KV cable Y-joint with integrated PD sensor for offshore windturbine grid connections
Venue: Elektronzaal, HB01, at 10.00 hrs
Title: Seamless Operation of a Microgrid Using BESS
Venue: Elektronzaal, HB01, at 9.00 hrs
Microgrids have two modes of operation: Grid-connected and islanded mode. Microgrids trade power in grid-connected mode and work autonomously when they are operating in islanded mode. Control of microgrids in each operation mode is affected by the bidirectional power transfer with grid, presence of power electronics, demand side management (DSM) and characteristic of distributed generations (DGs); however, switching between these two modes is even more challenging to ensure that microgrids operate efficiently and supply their sensitive loads during the transition. This thesis concerns possible control strategies to apply on battery energy storage systems (BESS) to have a smooth transition between grid-connected and islanded mode in a specific microgrid called CSGriP. Disturbances during intentional and unintentional islanding are taken into account, and a control strategy is proposed for the BESS to ensure a smooth transition with minimum disturbances in voltage and frequency at the point of common coupling.
Title: Design of mathematical model of a multilevel modular converter
Venue: Dijktstra zaal, HB09.150 at 13.00 hrs
The purpose of this thesis is to design a Multilevel Modular Converter, one of the recent developments in the field of Voltage Source Converters, which is capable of reducing the size of the capacitor filter banks, using MATLAB Simulink and establishing a relationship between the various parameters required to involved in the scalability and modularity of the converter with respect to the converter’s output power quality.
Title: Optimization and Energy Management of a Microgrid based on Frequency Communications
Venue: Van der Poelzaal, LB01.220 at 13.00 hrs
This study proposes an energy management system (EMS) that optimally operates a microgrid (MG) using frequency as the only communication signal. The EMS considers renewable energy sources, a micro-generator, a battery, critical and controllable loads. Demand-side and supply-side management strategies are included. Simulations use data from an existing MG to compare the EMS with a traditional control system.
Title: Sensorless Field Oriented Control in Modular Design Six Phase Permanent Magnet Synchronous Machine
Venue: Van der Poelzaal, LB01.220 at 9.00 hrs
Title: Optimal Power Flow and Pricing Mechanism For Bipolar DC Distribution GRids
Venue: Van der Poelzaal, LB01.220 at 14.00 hrs
The fast advances of renewable energy technologies will most likely lead to an increasing amount of distributed energy resources. Most are inherently DC or have a DC link which encourages the development of DC distribution grids. Low Voltage Direct Current distribution systems can potentially increase power quality, reliability and efficiency. Additionally, the affordability of DG and storage units promotes market participation from prosumers. As a result, new market models based on real-time pricing could encourage the use of energy when available as well as revealing investment opportunities with regards to renewable sources or storage units in an effort to increase reliability. Distribution grids are expected to be more subject to congestions as a consequence of the rising penetration of distributed generation and electric vehicles. A market closely linked to the physics of distribution systems should be developed to reflect congestions and losses in electricity prices.
The main contribution of this master thesis is twofold, an optimal power flow specifically designed for bipolar DC distribution grids is presented and used compute the economic dispatch. The novel power flow formulation in terms of voltages and currents guarantees that the solution is always physically feasible. Using this methodology, the utilization of renewable energy sources is optimized while the system's production cost minimized. Furthermore, a dynamic pricing mechanism is obtained from the optimization problem. Electricity prices which include both losses and congestions are directly obtained from the optimal power flow for each location in the network. Locational marginal prices for bipolar DC distribution grids has not been research before, interesting results were obtained in asymmetrical cases where the loading of pole exceeds the loading of the other pole. They can be used for pricing purposes as well as indicator that reveals investment opportunities.
To enable the control of ESS the model is formulated as a multi-period optimization problem and demand side management is incorporated in the model by assigning an indicator reflecting the willingness of users to purchase electricity. Finally, the model offers the possibility to site and size ESS in an effort to maximize the utilization of renewable energies and to manage congestions.
Title: Passive Filter Design and Optimisation of Harmonic Mitigation in Wind Power Plants (Dong Energy Sponsored Project.NTNU)]
Venue: RTDS, LB01.010 at 15.00 hrs
The primary scope of this thesis is to understand the sources of harmonics in the offshore wind power system and provide a mitigation strategy for the harmonics. Hence, to do the same the author needs a test offshore wind power system to analyze the results. Therefore, the start of this thesis is choosing a test case offshore windfarm system. After doing so, the test case system has to be modelled in a simulation platform carefully taking into consideration different electrical parameters like impedances and circuit parameterization that closely mimics the original electrical equipment (transformers, cables etc.) parameters. Once the modelling of the test case system is done the harmonic sources and their behavior have to be analyzed. Once the proper functioning of power system and harmonic pollution level are obtained, possible harmonic mitigation structures has to be discussed. The main aim of this thesis is to design and optimize passive filters for the test case offshore wind farm system. Once different state of art mitigation structures are described, the design of these passive filters or mitigation has to be initiated. After preliminary investigation and design of the state of art passive filter strategies the parameters on which optimization is to be conducted has to be decided. Upon making decisions on different parameters to be used, optimization of the passive filter design has to be conducted. Based on the results from various mitigation structures, an optimization algorithm can be developed. Once the optimally designed filter is ready a harmonic resonance check can be initiated. If there is harmonic resonance that can potentially cause disturbance for the proper operation of the offshore wind power system, techniques to shift these harmonic resonances have to be suggested. It is aimed to accomplish the above mentioned procedure to finally obtain optimal design features for various harmonic mitigation structures and optimally designed filters.
Title: Design and evaluation of powertrain architectures for battery electric vehicles
Venue: Van der Poelzaal, LB01.220 15.00 hrs
The continued increase in greenhouse emissions has recently raised serious environmental, economic and social concerns, giving electric propulsion an important role in future road transportation. The greater flexibility of electric vehicles versus conventional ones in terms of powertrain configurations has promoted the development of highly differentiated architecture topologies.
This work will investigate two electric powertrains with respect to energy consumption and efficiency: the standard single-motor architecture, derived from conventional internal combustion engine vehicles, equipped with a high-speed electric motor and a mechanical reduction system and the novel in-wheel topology with direct drives. The potential benefits of a two-speed transmission to improve performance and driving range of battery electric vehicles is also studied.
Title: Optimal placement and sizing of batteries using the Genetic Algoritm
Venue: Elektronzaal, HB01 at 9.00 hrs
Voltage rise and drop are one of the major problems in low voltage distribution networks. Usually they occur due to the large mismatches in demand and supply of power. An increase in the penetration of renewable energy sources (RES) is also a contributor to these problems. With the help of energy storage these problems can be successfully mitigated and the RES hosting capacity of the distribution networks can be increased. The effects of using this strategy can be maximized by optimal placement and sizing of energy storage. There are various tools used for the optimization processes and one of them is the Genetic Algorithm which has proven to be a good tool for this type of problems.
Title: Self-powered wireless current sensor; proof of concept of the combination of continuous current measurement and energy extraction using one Current Transformer
Venue: Dijktstrazaal, HB09.150, at 13.00 hrs
Due to changes in the electricity grid, and the awareness of the energy consumption, management of energy flows is an important business. For the management of energy flows, detailed information about the current, voltage and phase is needed. In this project current sensor based on a current transformer (CT) are considered. For the integration of current sensors in the grid there is a need for non-invasive current sensors that are easy to installable. The combination of continuous current measurement and energy extraction for powering the sensor electronics based on one CT. A prototype for a self-powered wireless current sensor that is able to measure current from 10 A to 240 A is realized. The used configuration can most likely be used for other current ranges as well.
Title: Investigation and modeling of modular machine topologies for wind turbine generation systems
Venue: Van der Poelzaal, LB01.220, at 9.30 hrs
As the wind industry is rapidly growing, wind turbines grow larger and new models are soon expected to reach ratings of 10 MW. The development of offshore wind farms is another major trend in the industry. In this context, increasing turbine availability emerges as a critical issue: Modularity is seen as a promising approach to respond to this need.
Modular systems can be decomposed into a number of independent ’modules’ or components. Such systems can have their faulted modules bypassed and continue operation after fault, increasing system availability. Different levels of modularity have been proposed: Systems with modular converters or systems with modularity both in the converter and machine, with possible levels of modularity in the machine itself. Focusing on the machine-side of modularity, this thesis aims to produce a comparative study of important modular machine topologies proposed in literature.
On Wednesday, 12 October, Executive Board President Tim van der Hagen, Dean of the Faculty of Electrical Engineering, Mathematics and Computer Science Rob Fastenau, Head of the Department of Electrical Sustainable Energy Miro Zeman, and Pavol Bauer, who leads the Direct Current (DC) Systems, Energy Conversion & Storage group, presented the first solar-powered wireless charging station for electric bikes.
Pavol Bauer said, "This is a major step forward in terms of sustainable transport and accelerating the energy transition because the combination of solar energy, wireless charging and electric bikes is unique. In this charging station, we charge the DC battery in the bike with the solar energy from the eight solar panels via the DC supply. The charging station can also store 10 kWh of solar energy in the batteries, enabling it to function independently."
Practice and research
The charging station is ready for immediate use: it can accommodate four electric bikes, an electric scooter and a research bike that are charged wirelessly. The charging station also serves as a living lab, a testbed for further research. In the last two years, ten students have graduated on the strength of their work on the project. For example, a student of Electrical Engineering, Mathematics and Computer Science designed a DC system and created a system to enable the bike to be charged wirelessly, another calculated and determined the output and position of the solar panels, and an Industrial Design Engineering student was responsible for designing the charging station.
How it works
The electric research bike is equipped with a dual stand and a small coil. At the charging station, the bike can be parked on the stand on a magnetic tile. The bike is charged directly via the coil. The user can monitor the charging status on a built-in screen on the charging station or on his or her mobile phone. Wireless charging takes around the same time as the 'conventional' charging of electric bikes.
It is anticipated that the eight panels will generate sufficient energy to power the electric bikes and the scooter in winter. In summer, any excess power will be fed to the electricity grid. Pavol Bauer's group now plans to work on the further development of wireless charging for various bikes and scooters. The ultimate aim is for the charging station to consist solely of several tiles used as a solar panel, which can be cycled on, known as solar roads. Integrating solar cells and the wireless charging system makes an expensive system unnecessary.
The wireless charging station has been made possible thanks to grants from the TU Delft Deltas, Infrastructures & Mobility Initiative, the 3E Foundation and Climate-KIC.
More information can be found on www.solarpoweredbikes.tudelft.nl
Prof. Pavol Bauer (DC systems, Energy Conversion & Storage), P.Bauer@tudelft.nl, +31 15 2784654.
Sharita Balgobind (press officer TU Delft), U.S.Balgobind@tudelft.nl, +31 15 2781588.
Met gepaste trots willen wij u hierbij graag uitnodigen voor het bijwonen van het Nationaal Debat e-Bike; Duurzame vervanging voor auto’s? We beginnen het programma om 11.30 uur met de presentatie van het “Solar e-Bike Charging Station” door Tim van der Hagen, Rob Fastenau en Miro Zeman (TU Delft) op 12 oktober a.s. op de FreeZone D van de TU Delft Campus (naast EWI, zie ook de plattegrond).
Na de presentatie zal er om 12.30 uur een debat plaatsvinden (lunch inclusief) in Zaal D van de faculteit Civiele Techniek. Tijdens dit debat zullen Wim Bot (Fietsersbond), Sacha Sylvester (TU Delft), Arjan van Timmeren (AMS) en Martin Guit (Gemeente Rotterdam) verschillende invalshoeken belichten over e-Bikes. Aansluitend volgt een panel discussie onder leiding van Marcel Hertogh (DIMI). Na het debat zal Pavol Bauer om 15.00 uur zijn intreerede “How direct will the future electricity be?" houden in het Auditorium van de Aula.
Bijgaand sturen wij u het volledige programma en een plattegrond van de campus. Deelname is gratis, maar registreren is verplicht. Wij hopen u te verwelkomen op 12 oktober a.s.!
Dr.ir. Bauer bij besluit van het College van Bestuur van 26 januari 2016 benoemd tot hoogleraar in de Faculteit Elektrotechniek, Wiskunde en Informatica aan de Technische Universiteit Delft, om werkzaam te zijn op het vakgebied DC systems, Energy Conversion & Storage, is ter gelegenheid van zijn ambtsaanvaarding voornemens een oratie te houden, met als titel:
‘How direct will the future electricity be?’
Datum: woensdag 12 oktober 2016
Aanvang: 15.00 uur
Locatie: Aula (Auditorium/3e etage) Mekelweg 5 te Delft
De Rector Magnificus van de Technische Universiteit Delft, prof.ir. K.C.A.M. Luyben, nodigt u hierbij uit tot het bijwonen van deze academische plechtigheid. Na het uitspreken van de rede is er gelegenheid tot het aanbieden van gelukwensen.
PhD student Gautham Ram gave a talk on "Breakthrough technology in Power converter design" at the EMVT event "INSIDE THE BOX EN OUT OF THE BOX: OVER INNOVATIES IN POWER CONVERTERS EN WAT DAT BETEKENT VOOR SYSTEEMINTEGRATORS" as part of the World of Technology and Science (WOTS) fair 2016 at Utrecht. The presentation focused on developments in power converter design related to SiC and GaN devices, powdered alloy core inductor and multi-level modular converters (MMC). The event information and slides can be accessed here.
Title: Brushless Doubly-Fed Induction Machines for Wind Turbine Drive-Train Applications
Venue: Aula Senaatzaal at 10:00 hrs
Wind technology has shown a rapid development over the last decades, which includes trends towards increasingly demanding grid requirements and the emergence of large multi-MW offshore wind turbine installations. Because the wind energy market is still growing, opportunities for further technological advancement are provided. The development of the brushless Doubly-Fed Induction Machine (DFIM) is a good example of such a technological advancement. The brushless DFIM provides an interesting alternative to the commonly applied conventional DFIG in modern wind turbines. Both of these generator systems show similar operating characteristics, though the brushless DFIM has some advantages that include an increased robustness and reliability and a decreased need for maintenance, due to the absence of brushes and slip-rings. Although the modern brushless DFIM is the result of more than 100 years of evolution, its complex nature has prevented its commercial development. Therefore, this research work presents developments related to brushless DFIM modelling, to provide more insight into this machine’s operating principles and characteristics. It further presents developments in the field of brushless DFIM design and optimization, to generate cost-effective machine designs. Lastly it presents developments in the field of brushless DFIM control, to provide the ability to control this machine’s output behaviour in a stable and responsive manner. The presented results must aid in the advancement of a commercial brushless DFIM for wind turbine drive-train applications.
Title: Wireless Charging of Electric Vehicle with 11kW Induction Chargeers
Venue: Van der Poelzaal, LB01.220 at 9.00 hrs
The Thesis is about the construction of an 11kW inverter in to charge an electric vehicle wirelessly. The main concern of that thesis, except of the hardware implementation of the total system, is the proposal of an appropriate filtering topology that will eliminate the EMI produced by the switching of the square wave voltage source, produced by the inverter.
Title: Influence of Moisture in Insulating Paper on Reducing Post-impregnation Standing Time of Oil-filled Power Transformers
Venue: Elektronzaal, HB01, at 14.30 hrs
Standing time, prior to testing, is a necessary part of the oil-filled transformer manufacturing
process and its duration is design dependent. Caution on part of the manufacturer to avoid
failure of expensive transformers leads to the overestimation of standing time, consequently
impacting annual production. Thus, a need for optimizing (reducing) standing time arises.
The absence of Partial Discharges (PDs), above predetermined limits, during testing indicates
sufficient standing time. Moisture in oil-paper insulating system is a source of PDs. Thus,
moisture and its migration between oil and paper can determine the duration of standing
time. Moisture is absorbed by and extracted from paper during the tightening and vacuum
steps of the production process, respectively. The aim of this thesis is to determine if paper
actually plays a role in determining the standing time with partial discharge testing used as the
primary diagnostic tool.
Title: Frequency Based Cellular Microgrid Control
Venue: Dijkstrazaal, HB09.150, at 14.00hrs
The thesis proposes a controller that enables microgrids to have a modular structure, to be ﬂexible in terms of linked energy consumers and resources, and to offer the possibility of prioritized demand side management, while avoiding the need of employing a dedicated communication network. For this, the control strategy applies droop control, combined with a variable frequency setpoint depending on the state of the grid. Furthermore, a strategy for applying demand and supply side management is established, enabling the grid to operate stable using renewable energy resources.
The reactions of the proposed control structure have been studied in a broad range of cases, using simulations performed in DIgSILENT PowerFactory. Results show that the proposed controller has a satisfactory performance, it is able to interface multiple microgrids without the necessity of dedicated communication, and both load shedding and renewable energy curtailment schemes are initialized when needed.
Title: Transient Analysis of DC Distribution Grids
Venue: Van der Poelzaal, LB01.220, at 12.30hrs
Title: Single Pick Up Dual Frequency IPT Systems
Venue: Snijderszaal, LB01.010, at 10.30hrs
A dual frequency IPT (DF-IPT) system focuses on reducing the mutual coupling between two transmitter coils by tuning each coil to a different resonance frequency, 85 kHz and 100 kHz. Currently, a DF-IPT system consists of two receiver coils, each tuned to receive the power transferred by the corresponding transmitter. Such a system not only gets bulkier and more expensive, but also reduces the tolerance of misalignment between the receiver and transmitter. This thesis aims at resolving the drawbacks of the existing DF-IPT by developing aDF IPT system with single pick up networkwhich is capable of tuning to both 85 kHz and 100 kHZ.
Title: Applications and Effects on a Medium Voltage Grid
Venue: Van der Poelzaal, LB01.220, at 13.30hrs
When integrated into electrical networks Electric Energy Storage has the potential of numerous technological and financial benefits. The importance of Electric Energy Storage is growing as more renewable energy sources and higher consumer loads are added to existing networks. Peak shaving appears to have the most potential benefits when applied to an electrical network. These benefits are expected to be power supply increase, congestion relief, transmission upgrade deferral, and distribution upgrade deferral. Five different scenarios are tested in order to determine the impact of Electric Energy Storage on a real world case. From the results of this examination and research it is concluded that it is possible to use peak shaving to increase the power supply, reduce congestion, and defer transmission and distribution upgrades on a radial configured network.
Title: Power transformers: Influence of moisture in pressboard insulation on standing time
Venue: Van der Poelzaal, LB01.220, at 9.00hrs
A large power transformer, is often, a custom designed equipment that entails a complex and capital intensive manufacturing process. Due to its importance in the power system, transformers should perform reliably under the conditions for which it has been designed while keeping the manufacturing costs to a minimum.
Standing time is the period (during manufacture) between the end of tank filling with mineral oil and factory acceptance tests (FAT). The aim of the thesis is to optimize the production of transformers by investigating how moisture in pressboard insulation affects standing time.
Title: Lost optimising design alternatives for the primary electrical distribution System on Floating Liquid Natural Gas vessels
Venue: Dijkstrazaal, HB09.150, at 13.30hrs
Shell is developing a floating facility to produce, treat and liquefy natural gas, called a Floating Liquid Natural Gas (FLNG) vessel. To make the FLNG vessel a cost effective option for LNG production the costs of the vessel need to be reduced. This thesis evaluates which changes to the current electrical system on FLNG vessels are able to reduce the total costs of the vessel.
Title: Optimal topology for a three port PV-EV-Grid Power Converter
Venue: Van der Poelzaal, LB01.220, at 10.00hrs
This thesis focuses on the search for the optimal converter which can be used as a single solution for both EV charging and PV energy production. The three port converter must be able to charge the battery from both the grid and solar power, and inject current to the grid from both the solar array and the EV battery, allowing V2X operation. Maximal efficiency is wanted to reduce heating and maximize profit while keeping the overall volume low, making the product appropriate for both residential and industrial applications.
Title: Seamless Transition of multiple Microgrids between the Backbone Interconnected and the Islanded Operational Modes
Venue: Timmanzaal, LB01.170, at 15.30hrs
This thesis considers an extended grid that is composed of several cellular micro-grids interconnected through a low voltage backbone. The aim of the thesis is to develop adequate controllers that would achieve the seamless transitions of these micro-grids between the islanded and the backbone interconnected operational modes. A key feature is the lack of intra-micro-grid communication. The frequency is used as the main communication signal and regulates the operation of the extended system.
Title: Electromagnetic Evaluation and Optimization of a Combined Inductive Power Transfer and Inductive Healing Road
Venue: collegezaal F, at 09.00hrs
The highway of the future will implement serveral sustainable technologies, like inductive power transfer to EVs and low maintenance roads that use induction heating to heal cracks in the asphalt. This thesis investigates the possibility to combine the two technologies in the same road, where the main challenge is to reduce the losses in the asphalt during inductive power transfer, while maintaining the possibility to heat the asphalt by means of induction heating with the same system when desired.
Title: Control of DC Microgrids with current limiting inductors and demand response
Venue: Elektronzaal, HB01, at 10.00hrs
This study evaluates the dynamics of DC microgrids (DCMG) with the use of: grid inductive elements, as a short circuit current limiting inductance used for protection; the use of to current rate of change control in loads; and demand side management (DSM) techniques such as voltage dependent demand response (VDDR) itself and the integration of price prediction algorithms by VDDR.
Title: Virtual Inertia Emulation in islanded microgrids with energy storage system
Venue: Meetingroom 1.4, LB01.210, at 13.00hrs
Title: Residual Current Protection of a Meshed DC Distribution Grid with Multiple Grounding Points
Venue: Timmanzaal LB01.170, at 13.00hrs
Title: Load side detection of series ARC in Dc microgrids by simulation and experimental validation
Venue: RTDS room LB03.010, at 15.30hrs
Title: Reliability Comparison of Multilevel Converters for Wind Turbine Systems
Venue: Dijkstrazaal HB09.150, at 13.00hrs
Title: Three dimensional Finite Element Modeling of a Brushless Doubly-fed Induction Machine
Venue: Van der Poelzaal, LB01.220, at 13.30hrs
BDFIM can be a potential candidate as a generator in offshore wind farms. In this thesis, we explore ways to develop a 3D model of the machine. Special emphasis is placed upon the implementation of iterative solvers and multigrid preconditioning to solve large scale matrices resulting from 3D finite element formulation.
Title: Comparison of AC and DC Interconnectionin an Office Building with PV and Electric Vehicles
Venue: Van der Poelzaal, LB01.220, at 9.30hrs
This thesis provides comparisons on efficiency, control and protection, of an integrated PV and Electric Vehicles (EVs) in an office building with 3φ 400V AC and 750V DC interconnection. The maximum efficiency difference between
(ȠDC - ȠAC) is 2.2% at the lowest possible energy exchange with the grid. AC is very stable due to its direct connection to the infinite grid while DC requires buffer capacitors to support the system stability. Furthermore, a very fast protection devices are required to prevent the grid’s converter disconnection due to the high fault current.
Research of the DCE&S group into DC grids has been featured in Delft Outlook Magazine July 2016 issue - Laura Ramirez Elizondo and Pavol Bauer believe it is time for a complete overhaul of our electricity grid. Laura and Pavol are running the Direct Current. "The future role of energy companies will change enormously. I think that energy companies will largely take on a service provider role." Read the full article here.
Power transformers are extremely important for the power system and most of its failures are caused by on-load tap changer. There are various diagnostic techniques to know the condition of on-load tap changer. In this thesis an investigation of automatic analysis on dynamic resistance measurement data of on-load tap changer is carried out. The analysis is a combination of measuremed data, tapped winding and tap changing mechanism.
Title: Development of a Rogowski Coil Sensor for Partial Discharge Detection in Medium and High Voltage Cables
Venue: Lipkenszaal, LB01.150, at 10.00hrs
Nowadays, submarine cables are an important part of the electrical infrastructure and they are becoming more relevant due to the integration of the offshore renewable energies in the grid. For this reason, the reliability of the offshore connection with the mainland must be ensured.
This research project develops a sensor suitable for online monitoring of partial discharges in submarine cables for fault detection. The aim of this research is to propose a sensor design for cable online monitoring considering the effects of attenuation and the particularities of coaxial cables for submarine applications.
After a detailed study of the different sensor technologies , analyzing and comparing their advantages and limitations, the Rogowski coil sensor was selected due to the great flexibility, robustness and its suitability to adapt and satisfy the requirements for this specific application.
The electromagnetic sensor prototype is based on a Rogowski Coil design to measure at least 10pc PD pulses while handling the 50Hz electromagnetic fields. Additionally, the level of intrusion of the sensor within the insulation is extremely low in order not to compromise the integrity of the insulation. This sensor is validated by simulations and laboratory means.
Title: Advancing sustainable transportation by charging EVs with PV power at the workplace — An optimal charging strategy
Venue: Snijderszaal, LB01.010, at 9.30 hrs
This thesis presents the design of an energy management system (EMS) capable of forecasting PV power production, that optimizes power flows between photovoltaic (PV) system, grid and EVs at the workplace. The aim is to reduce energy demand on the grid by increasing PV self-consumption while minimizing charging cost and consequently increasing sustainability of the EV fleet. The developed EMS consists of two components: an autoregressive integrated moving average (ARIMA) model to predict PV power production and a mixed-integer linear programming (MILP) framework that optimally allocates power to minimize charging cost. The results show that the developed EMS is able to reduce charging cost significantly, while increasing PV self-consumption and reducing energy demand from the grid. Furthermore, during a case study analogous to one repeatedly considered in literature, i.e. dynamic purchase tariff and dynamic feed-in tariff (FIT), the EMS reduces charging cost by 118.44% and 427.45% in case of one and two charging points, respectively, when compared to an uncontrolled charging policy. The optimization problem is modeled in GAMS, whereas the ARIMA process is modeled in Matlab and subsequently, the EMS is simulated in Matlab.
Title: Parameters Identification of Brushless Doubley –Fed Induction Generators
Venue: RTDSzaal, LB03.010, at 13.00hrs
Brushless doubly-fed induction generators(BDFIG) has the potential to replace the current-popular doubly-fed induction machine in the wind turbine market. However how to precisely derive its equivalent circuit parameters is hard to achieve. This paper provides a finite element modeling (FEM) method to derive BDFIG's equivalent circuit parameters with saturation being taken into account.
PhD students Gautham Ram and Venugopal Prasanth were awarded the best poster award at the Erasmus Energy Forum 2016 held in Rotterdam on 19th May 2016. Their poster was titled 'Charging of EV from PV and Contactless Power'. The news was highlighted in the 'Flits' newsletter for employees of the faculty of Electrical Engineering, Mathematics and Computer Science which can be accessed here.
Title: Flexible Power Transfer Network
Venue: Snijderszaal, LB01.010, at 15.00hrs
For past 100 years the power transmission to the end customer was secured by 50 Hz AC network. In recent years, with introduction of many portable devices, the flexibility and safety of this network became an issue. Therefore, a significant research interest was directed towards introduction of inherently safer and more flexible solutions - inductive power transfer (IPT) networks. From the early time of development of IPT networks, it was recognized that to design a control for IPT system the missing communication link between primary side and possibly multiple secondary sides is an issue. However, with the rise of renewable resources, a question arises how to design a control for an IPT system
with multiple primary sides and multiple secondary sides. This thesis is one of the first documents to treat the control problem of multiple-source IPT system in detail. The main result of this thesis is a novel sliding mode controller based on power-balance of the system. The proposed controller is able to simultaneously control multiple independent sources connected to the
IPT system in an efficient manner without any communication between primary sides or secondary sides. The proposed sliding mode controller and equations derived in this thesis are validated by a simulation. To strengthen the claim, the simulation results for 1 source and 1 load were compared with the real world
measurement to prove the validity of the simulation tools.
Title: Investigation into the design domains' interdependencies of an inverter - case study of an aerospace inverter for extreme conditions
Venue: Van der Poelzaal LB01.220, at 13.00
PhD student Alex defended his PhD thesis titled "Analysis of the mechanisms determining the thermal and electrical properties of epoxy nanocomposites" on 25th January 2016 at 1000 at Aula. He graduated cum laude !
The IEEE PELS/IAS student board was featured in the IEEE Industry Applications magazine issue for Jan/Feb 2016. The article can be accessed here.
DCE&S group was featured in the Delta magazine in January 2016. The article can be accessed here online.