1 Contents 1 Contents. 1 2 Abstract 3 3 Introduction.
4 4 Objectives. 4 4.1 Bidirectional Power Flow.
. 5 4.2 Power Quality Performance. 5 4.
3 Simulation. 5 4.4 Hardware Implementation. 5 4.5 Evaluate performance. 5 5 Literary Review..
5 5.1 Current status of both PEV and smart grid technologies and markets. 6 5.1.1 Plug in Electric Vehicles. 6 5.
1.2 Smart Grids. 6 5.
2 Environmental impact of both PEVs and smart grid technology. 6 5.2.1 Environmental 6 5.3 Ethical impact of this project, PEVs and smart grids. 6 5.
3.1 Safety. 7 5.3.2 Recognition. 7 5.
3.3 Privacy. 7 5.3.
4 Security. 7 5.4 Technical investigation of bidirectional charging systems. 8 5.4.1 Grid. 8 5.
4.2 AC Filter. 8 5.
4.3 AC – DC Converter. 8 5.4.4 DC – DC Converter. 8 5.4.5 Batteries.
8 6 Work Plan. 10 6.1 Mind Map. 10 6.2 Gantt chart 11 6.3 Risk Management 11 7 References. 11 8 Appendix A Risk Assesment 12 9 References.
15 2 AbstractThrough the integration of renewable energy sources thegrowing demand for electrical energy. The grid is becoming more and more diverse and complex. This hasaccentuated the need reliable, secure and sustainable solutions. Solid statepower electronic converters will be utilised to tackle these complexities andimprove the quality of national grids.
Plug-in electric vehicles (PEVs) have the ability to act asboth a load and/or as source of energy with respect to the grid. ConnectingPEVs to the grid allows for them to be used for ancillary services such asreactive power control and load balancing. By the use of bidirectional power flowtechnology, this project aims to evaluate the performance of bidirectionalchargers individually and as an aggregated groups.
Three elements are required for successful vehicle to grid operation:power connection to the grid, control and communication between vehicles andthe grid operator, and on-board/off-board intelligent metering. Acharging/discharging infrastructure must be deployed. Economic benefits of V2Gtechnologies depend on vehicle aggregation and charging/recharging frequencyand strategies. The benefits will receive increased attention from gridoperators and vehicle owners in the future.The purpose of this project is to design and build a fullyfunctional bidirectional charger for the application of PEVs. The bidirectionalcharger should support bidirectional power flow while not having a negativeimpact on power quality.
3 IntroductionPlug inelectric vehicles (PEVs) are becoming more and more prevalent on the market. APEV can act as both load or as an energy source. Smart grid concepts beingexplored are vehicle-to-grid (V2G) and grid-to-vehicle (G2V). PEVs could beused for energy storage for the electrical power system, V2G, and as controlledloads, G2V.
1Policiesdirectives such as the 2009 EU renewable energy directive has driven the growthof renewables on national power systems. The growing trend towards renewableenergy has increased the importance of energy storage. The intermittency ofrenewable energy systems can lead to the curtailment of generators. Forexample, when wind is high and the load is low some wind turbines may need tobe switched off. This along with other possible ancillary services such as reactivepower support, frequency control, and load balancing has lead to research anddevelopment of V2G technologies. One of thecomponents of V2G and G2V technology is bidirectional power flow. This projectwill encompass the design and development of a bidirectional charger. Thebidirectional charger will have the primary ability to control the flow ofpower from an AC power supply to a battery or from the battery to the AC powersource.
The use of solid state switches shall not have a negative impact onpower quality. Solid state switching, and pulse width modulation, shall providethe ability of reactive power control and load balancing. 4 ObjectivesThe overarchingobjective of this project is to design, model, build and test a bidirectionalcharger for use with PEVs. The bidirectional charger shall have the ability tocontrol the flow of power from V2G or G2V. The bidirectional charger shall bedesigned using power electronics and solid state switching devices, a highlevel overview can be seen in Figure 1.
Figure 1 High Level Block Diagram ofBidirectional ChargerMatlab willbe used to design and build the simulation model. The model will be used to aidin the design of hardware version of the model. All components will be selectedand controlled using mathematical techniques. The objective of the project canbe further broken down into sub sections.
4.1 Bidirectional Power FlowBidirectionalpower control shall be achieved by controlling the direction of the dc currentflow of the battery. This determines whether the PEV will be operating in a V2Gor G2V mode. The amount of power being delivered or received will be determinedusing pulse width modulation (PWM). 4.
2 Power Quality PerformanceAnalysiswill be performed due impact of the high frequency switching on the current. Anappropriated filter will be designed using basic electrical elements such ascapacitors, inductors and resistors to reduce the impact of this switching.4.3 SimulationAs a Matlabwill be used to design and build a model of the bidirectionalcharger. The model will be test using a real time simulator. 4.4 Hardware ImplementationA prototypecharger will built be using the calculated values of components. Theappropriate rated of the components are to be used such as voltage, currentpower etc.
4.5 Evaluate performanceTheperformance the hardware implementation will be evaluated against the modelledversion. The efficiency of the charger will analysed and the losses will beaccounted for.5 Literary ReviewResearch consistedof a search and review of available literature. This included a full search ofinternational journals, conference proceedings, international standards, andpublished texts from respected bodies and parties in the area. Internet basedsearches of online articles, press releases, government documents, professionalpublications, vendor literature, and industry publications.The areasdeemed necessary for further research can be divided into three main sections:· An overview of current status ofboth PEV and smart grid technologies and markets· Environmental and Ethical impact ofboth PEVs and smart grid technology · Technical investigation ofbidirectional charging systems5.1 Current status of both PEV and smartgrid technologies and markets5.
1.1 Plug in Electric Vehicles5.1.2 Smart Grids5.2 Environmental impact of both PEVsand smart grid technology5.2.1 Environmental Issues related to air pollution are increasingly relevant inEU countries.
The parameters that are usually monitored for measuring airquality are related to the concentration of specific substances (i.e., PM10,PM2.5, NO2, C6H6, and CO2), and the sectors that most influence the presence ofthese pollutants in the environment are industry, transport, agriculture anddomestic heating. 2With regards to greenhouse gases and pollutant emissions,the overall contribution of PEVs is certainly lower than conventional ones. For example, the CO2 emissions of a VolkswagenGolf running are respectively 0 g/km for the PEV version, 36 g/km for the PHEVversion, and 122 g/km for the ICE version 3. There are no CO2emissions as a results of a travelling PEV. There are however CO2 emissions asa result of the original energy production, this can however be further offsetby producing energy from renewable sources such as solar or wind energy.
5.3 Ethical impact of this project, PEVsand smart gridsEthics is abroad topic covering many areas. This project will be completed to meet withEngineer’s Ireland Code of Ethics. As such, two main areas requireconsideration safety and recognition. Smart Grids use data and digitalelectronic systems to control the interaction of various sources of power. Theuse of data and control systems system opens the possibility of the violationof privacy and security of the individual and the collective.
As PEVs andbidirectional chargers are relatively new technologies the consideration mustbe given to poorer communities. 5.3.1 SafetyDuring thedesign and implementation of this the safety of public and persons working onthe project shall not be jeopardised.
As this project involves the use ofelectricity the wiring of the hardware will adhere to the ETCI National Rulesfor Electrical Installations. Appropriate signage5.3.2 Recognition Allmaterials researched and used in this project will be referenced to giverecognition of the work completed by others. The help and efforts of colleagueswill also be recognised and acknowledged.5.3.
3 PrivacyThemonitoring and management of smart grid components requires constant anddetailed data collection. The issue of data being collected is a major ethicalconsideration. For smart grids in particular, the data gathered from smartmeters may be able to show individual consumers minute by minute powerconsumption habits. 45.3.
4 SecurityFor theindividual, the information collected could indicate when people are likely tobe at home. This is an issue of personal security if this information was tofall into the wrong hands. There is a need for a legal framework to be built,as the current legal framework is not suitable with these newtechnologies.
5 On the other hand this information may be usedto reward customers who use electricity to the benefit of grid operators. Forexample if non-essential loads were reduced during peak demand times. Fromnational perspective, the combining information and communication technologywith national power systems introduces the security issues of the internet.
Ifpower systems are exposed to hackers this can lead to power disruptions whichcan have implications on national security and safety.22.214.171.124 EquityEthicalissues arise when dealing with smart grids, since poor communities may notafford the high costs associated with the necessary equipment to install a smartgrid technologies. 6Subsidies to these communities may be required. The question must also be askedthat should consumers be burden with management of the load.
5.4 Technical investigation ofbidirectional charging systemsFor thisproject a major objective is to design, model and simulate a bidirectionalcharger. The design will be implemented as a hardware model. A bidirectionalcharger can be broken down into a high level components. Research 5.4.
1 GridThe nominalsingle phase voltage in Ireland is 230 V 50 Hz. 7 The bidirectional chargerwill be designed to these ratings and comply with the ESB networks ‘ConditionsGoverning the Connection and Operation of Micro-generation’, document numberDTIS-230206-BRL. This document sets out the limits such as power factor,harmonics, power ratings and disconnection conditions to prevent islanding ofthe grid. A transformer may be required to reduce the magnitude of the voltageto coordinate with the batteries. 5.4.2 AC FilterThe primaryfunction of the AC filter is to improve power quality such as introducingharmonics and bad power factor. The AC filter will be built using a combinationof passive devices.
5.4.3 AC – DC ConverterThe AC – DCconverters purpose is to convert AC current to DC current in G2V mode and DC toAC in V2G mode. It is envisaged that this will be designed using IGBTs in a Hbridge arrangement. PWM will be used to control the switching frequencies ofthe IGBTs.5.4.4 DC – DC ConverterThe DC toDC converter controls the direction of current flow to or from the battery.
Afterreviewing the current topologies of DC to DC converters, 8 9,it was decided to use a buck boost arrangement. This was chosen due to the simplicityof using only two IGBTs to direct the flow of current. 5.4.5 BatteriesBatteries inPEVs are typically lithium-ion and are usually arranged in series. 10 6 WorkPlanInitially ideasbased upon research will be used to design a crude simulink model in Matlab.
Using this model a deeper understanding will be used to develop of eachcomponent. The design of the system lends itself well to modular type design.Each component can be part can be designed individually initially and thenintegrated together at a later stage. 6.
1 Mind MapA mind map,Figure2, was used to identify and visualise the stagesof the project. The project can be divided into three key sections:? Preparation:Research and Work Plan ? Implementation:Design, construction, testing and analysis? Evaluation:Analysis of test results, reporting Figure 2 Overall Work Plan Mind Map6.2 Gantt chart 6.3 Risk Management 7 References·