Department of Electrical and Electronics EngineeringDepartment of Electrical and Electronics Engineering

SREE VIDYANIKETHAN ENGINEERING COLLEGESREE VIDYANIKETHAN ENGINEERING COLLEGE(AUTONOMOUS)

Sree Sainathnagar,A.Rangampet,TirupathiSree Sainathnagar,A.Rangampet,Tirupathi--5171025171022009-2011

M.SRISAIRAMREDDYII M. Tech (EPS), III Semester

ROLL NO. : 09121D0704

Interconnection of Electrical Energy Storage System For Power Quality Improvement

byby

Under the esteemed guidance of Mrs.R.KRISHNA PRIYA, M.E.

Assistant ProfessorDepartment of EEE, SVEC

A seminar on

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Objective

Introduction

Energy Storage Device

Types of Supercapacitor

General Block Diagram of a DC-DC Converter

Addition of Control System for Regulation of

Output Voltage

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Buck Converter

Boost Converter

Conclusion

References

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With the Development of renewable energy power generation,microgrid, we effectively meet the growing power demand.

Energy storage system based on supercapacitor , cannot onlybe energy buffer but also improve the power quality of powersystem.

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The energy storage is playing an increasingly important role in the electrical power system

The different types of energy storage systems are 1) Photovoltaic generation system (PVGS)2) Fuel cell generation system (FCGS)3) Battery 4) Supercapacitors(SC)

Relative on these energy storage concerns it were simulateddifferent dc/dc converters, using the ATP Program to observetheir behavior on different parameters variations, such as: dutycycle, switching frequency, and capacitance.

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Electrical energy storage methods

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Supercapacitors are an advanced version of capacitors withunique ability to combine energy storage capabilities.

These robust devices can be charged and discharged 1000s oftimes and will typically outlast a battery.

Life span will be 10 years or more.

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Specific Energy= (U*I*t)/m

Specific Power= (U*I)/m

v=VoltageI=Currentt=Time(sec)m=Mass(kg)

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The principle of supercapacitors is based on the creation ofan electrochemical double layer by accumulation of electricalcharges at the interface between an ionic solution (electrolyte)and an electronic conductive material (electrode)

Store charge non- Faradaically

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Pseudocapacitor store charge faradaically through thetransfer of charge between electrode and electrolyte.

This faradaic processes may allow pseudocapacitor toachieve greater capacitances and energy densities.

The electrode materials that are used to store charge ispseudocapacirtors are

1) conducting polymers

2) Metal oxides

The hybrid capacitor consists of a activated carbon cathodelayer and the carbonaceous anode layer and a separator.

It store charge by faradaic and non-Faradaic processes

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Can be charged and discharged almost an unlimited numberof times

High power density

Do not release any thermal heat during discharge

There is no danger of overcharging; when fully charged thesupercapacitor simply quits accepting a charge

Operating temperature range as great as between -50C and 85C

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For load leveling in electric and hybrid vehicles as well as in traction domain.

Telecommunications

Power Quality

Energy density wh/kg

Typical lifetime (years)

Power density w/kg

Time of discharge (s)

Time of charge (s)

Efficiency (%)

capacitors batteriesEDCL

< 0.1 3 100

95

30

10-3-10-6

10-3-10-6

107

85-98

30

0.3-30

0.3-30

106

70-85

5

1000-10000

>1000

100

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General Block Diagram of a DC-DC Converter

A dc/dc converter is a device that accepts a dc input voltageand produces a dc output voltage.

Typically the output produced is at a different voltage levelthan the input.

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PWM

H(s)

vg = unregulated dc voltage

PWM=pulse width modulation

The model implemented in Alternative Transients Program(ATP) program

Model of the buck chopper implemented in ATPDraw

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To evaluate the quality of the converter output waveform canbe expressed by using the Fourier analysis data to calculatethe total harmonic distortion (THD) in relative

Firstly, the influence of the duty cycle variation on the totalharmonic distortion of the output voltage is investigated.

Vo= α Vs where α = Ton /(Ton+Toff )

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Table 1

Graph for the Variation of THDV with the duty cycle

α 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

THDv 3.67 3.26 2.85 2.44 2.04 1.63 1.22 0.81 0.41

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We can be observe that the output voltage is lower ondelta=0.1 that means a directly proportionality betweenoutput voltage waveform and duty cycle

Variation of the voltage and current for α =0.1,fsw=1000Hz

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The quality of the output waveform is improved at thesame time the output voltage is increased.

Variation of the voltage and current for =0.9,fsw=1000Hz α

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Secondly, the influence of the switching frequency variationon the total harmonic distortion of the output voltage isinvestigated.

The variation of THDv with the switching frequency is shownbelow figure

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Model of the boost chopper implemented in ATPDraw

The boost converter (step-up converter) is a powerconverter with an output dc voltage greater than its input dcvoltage.

c

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Graph for Variation of the THDV with the duty cycle .

α 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9

THDv 0.41 0.82 1.22 1.63 2.04 2.45 2.86 3.31 3.80

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Variation of the voltage and current for delta =0.5, fsw=10000Hz,L=100mH

Variation of the voltage and current for delta =0.8, fsw=10000Hz,L=100mH

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The simulations realized using the ATP Program

For the buck converter, variation of the duty cycledecreases the ripple.

For the boost it has a different variation because thereplies also influenced by capacitance value giving theboost operation.

.

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[1] R. Rotaru, "Interconnection of electrical energy storage systems forpower quality improvement" graduation project, Department of. PowerSystems, University POLITEHNICA of Bucharest, 2008.

[2] M. Brenna, G. C. Lazaroiu, E. Tironi, “High Power Quality and DGIntegrated Low Voltage dc Distribution System”, in Proc. IEEE PowerEngineering Society General Meeting 2006, June 18-22, Montreal,Canada, pp. 6

[3] Francis P.Malaspina and Fort Pierce, Fla. Supercapacitor Electrode andMethod of Fabrication Thereory, 1990

[4] Marie-Francoise, J.-N. Gualous, H. Berthon, A., Supercapacitorthermal- and electrical-behaviour modelling using ANN, IEEProceedings on Electric Power Applications, vol. 153, no. 2, pag. 252-263

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[6] N. Mohan, T. Undeland, W. Robbins, Power Electronics, John Wiley &Sons, 2003.

[7] A. Kislovski, R. Redl, and N. Sokal, Dynamic Analysis of Switching-Mode DC/DC Converters, New York: Van Nostrand Reinhold, 1994.

[8] IEEE recommended practice for monitoring electric power quality,IEEE Standard 1159, 1995

[9] . Miller, M. Everett, “Ultracapacitor Augmentation Of the Vehicle 14V Electrical System to Support Auxiliary 42V Subsystems,” The 14th International Seminar on Double Layer Capacitors and Hybrid Energy Storage Devices, Deerfield Beach, USA, Dec. 2004.

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