Curtin University of TechnologyDivision of Engineering, Science and Computing

Department of Electrical Engineering

Renewable Energy Systems 402/604Semester 2, 2007

Lecture 1

Professor Chem NayarOffice: 204:205

Telephone: 9266 7934Email: c.v.nayar@curtin.edu.au

Unit website: www.ece.curtin.edu.au/~pe301

Renewable Energy Systems 402/604

Tuition Pattern:5 Hours:

Lecture 2.00 hours, 1.00 weeklyTutorial 1.00 hour, 1.00 weekly

Laboratory 2.00 hours fortnightly

Assessment Details:Assignments : 4 0%

Assignment 1 (20%)

Assignment - 2 (20%)

Final Examination (2hours) : 60%Closed book , restricted exam.

( Students can bring a single page of A4 size notes handwritten or typed on both sides and calculators)

Recommended Texts and Principal References

1. H. L. Willis and W.G. Scott, Distributed Power Generation, Marcel Dekker Inc., 2000

1. G. Boyle, Renewable Energy, power for sustainable future, Oxford, 2004.2. J.F. Manwell, et al, Wind Energy Explained, John Wiley and Sons, 2002.3. S. Wenham, M. Green and M. Watt, Applied Photovoltaics, UNSW, ISBN 0 86758 909 4.2.S. AustraliaTM, "AS 4777.3: Grid connections of energy systems via inverters Part 3: Grid protection requirements," in Standards AustraliaTM, 2002.3.S. AustraliaTM, "AS 4777.1: Grid connections of energy systems via inverters Part 1: Installation requirements," in Standards AustraliaTM, 2002.4.S. AustraliaTM, "AS 4777.2: Grid connections of energy systems via inverters Part 2: Inverter requirements," in Standards AustraliaTM, 2002.

Renewable Energy Systems 402 Semester 2, 2007Week Day Topics Lecturer Duration Pre-readings Tutorial Assignment Due

1 31-Jul Introduction Prof. Nayar 4-6pm Lecture Notes2 7-Aug PV Systems 1 M. Dymond 4-6pm Lecture Notes Tutorial No.13 14-Aug PV Systems 2 M. Dymond 4-6pm Lecture Notes Tutorial No.24 21-Aug Wind Energy Systems 1 Prof Nayar 4-6pm Lecture Notes Tutorial No.35 4-Sep Wind Energy Systems 2 Prof. Nayar 4-6pm Lecture Notes Tutorial No.46 11-Sep Wind Energy Systems 3 Prof. Nayar 4-6pm Lecture Notes Tutorial No.57 18-Sep Energy Economics Prof. Nayar 4-6pm Lecture Notes Tutorial No.68 2-Oct Small Hydro Systems Dr. Sumedha 4-6pm Lecture Notes Tutorial No.7 Assignment No.1

9 9-Oct Fuell Cells 1 Dr. Sumedha 4-6pm Lecture Notes Tutorial No.810 16-Oct Fuell Cells 2 Dr. Sumedha 4-6pm Lecture Notes Tutorial No.911 23-Oct Distributed Generation 1 Dr. Sumedha 4-6pm Lecture Notes Tutorial No.1012 30-Oct Distributed Generation 2 Dr. Sumedha 4-6pm Lecture Notes13 6-Nov Study week Assignment No.2

Renewable Energy Systems 402/604 Lab

Overview of Renewable Energy Systems, Distributed

Generation

What Are Distributed Generators? Distributed generation (DG) systems are small

modular electric power generation units (

DG A Future Mode of Generation Central generation stations vs DG systems (now) Super computers vs Personal Computers (25 years ago)

Tremendous DG Market Potential Global electricity consumption40% of total global energy consumption Present global DG capacity30 GW installed capacity DG growth ratecurrently 8-9GW/year or 3% of newly installed

generation capacity; will be 6% of newly installed capacity by 2020

Global new-capacity Global new DG capacity

Rapid DG Growth Wind Capacity

0

10

20

30

40

50

60

70

80

90 91 92 93 94 95 96 97 98 99 00 01 02 03 04 05 06Year

Cap

acity

(GW

)

Cumulative CapacityInstalled Capacity

Rapid DG Growth PV Capacity

Driving Forces for Rapid DG Growth

ElectricitySector

EnvironmentalConcerns:

GHG reductionEnergy efficiency

Deregulation andEconomics:

TradeInvestment

Demands:

Increasing demandSupply qualitySupply security

TechnologicalInnovation

Electricity and GHG Emissions

Oi l 9. 9%

Nat ual Gas 18 . 8%

Coa l 34. 1%

Nuc l ear 17. 0%

Ren ewabl es 20 . 2%

Electricity: 0.51kg/kWh, or 20% of global GHG

Courtesy of Hydro Quebec

Increasing Electricity Demand

0

5000

10000

15000

20000

25000

2001 2010 2015 2020 2025

Year

Ele

ctri

city

Con

sum

ptio

n (T

Wh)

EE/FSUDevelopingIndustrializedNorth America

Annual World Electricity Consumption Will Increase at 2.3% (Developing Countries at 3.5%)

Energy Security: Oil and Gas Will Deplete, Sooner or Later

A Direct Drive Wind Turbine

A Wind Turbine System Kinetic Mechanical Electric Energy

Turbine input power

Turbine output power

Turbine performance factor Cp. Theoretical maximum Cp: Cpmax16/270.593, practical maximum Cp=0.4 - 0.5

Pwind = 2 31 12 2mu Au=

Pmech = 312Au Cp

Photovoltaic Cells Solar cell operation is based on the ability of

semiconductors to convert sunlight directly into electricity. In the conversion process the incident energy of light creates mobile charged particles in the semiconductor, which are then separated by the device structure and produce electrical current.

Characteristics of PV Cells

0

1

2

3

4

5

6

0 5 10 15 20 25

1000W/m2800W/m2

600W/m2

VI Characteristic CurveNominal 12V array

0

1

2

3

4

5

6

0 5 10 15 20 25

Voltage (V)

Cur

rent

(A)

0

20

40

60

80

100

120

Pow

er(W

)

4.679

17.4

Effect of Solar Radiation Level

0

1

2

3

4

5

6

0 5 10 15 20 25

1000W/m2

800W/m2

600W/m2

Effect of Temperature

0

1

2

3

4

5

6

0 5 10 15 20 25

0C25C

50C75C

This characteristic is important in determining the dc voltage window of grid connected inverters

Photovoltaic Power Systems

(a)

PowerElectronicsInterface

Utility

DC Input

(b)

(a)

PowerElectronicsInterface

Utility

DC Input

(b)

PowerElectronicsInterface

Utility

DC Input PowerElectronicsInterface

Utility

DC Input

(b)

Wind Electric Systems

Utility

GeneratorandPower Electronics

Utility

GeneratorandPower Electronics

Utility

GeneratorandPower Electronics

Power Electronic Converters: Enabling Technology for DG Systems

Converters in components, functions and systems of distributed generators

Functions of Power Electronic Converters for DG Systems

Power Conversion ac-dc, dc-ac, ac-ac, dc-dc; voltage and

frequency control Interconnection with Grid & System Protection

meeting requirements of interconnection standards Resource Control (optimize sources and loads)

maximum power point tracking Power System Support

power and reactive power control, dispatch etc.

Bidirectional Switching Power PoleRef: Mohan

Low Frequency PWM GenerationRef: Mohan

d

aNa VVd =

Single-Phase InverterRef: Mohan

twVv oo 1sin=

Single Phase Grid Connected Inverter

Three-Phase Inverter-Sine PWM

ddll VVV 867.0~23)( max =

Three-Phase Inverter- Sine PWM

Current Source/Voltage Inverter

A current source inverter (CSI) has an inductor in series with the DC input

Q1

Q2

Q3

Q4

L

Load

Idc

Io

Q1

Q2

Q3

Q4

Load

Vdc

IoC

A voltage source inverter (VSI) has a capacitor across the DC input Voltage controlled VSI (VCVSI) Current controlled VSI (CCVSI)

Voltage Controlled VSI

L

g

L

cgg

L

cgg X

VXVV

QXVV

P2

cos;sin ==

Current Controlled VSI

sin;cos gggggg IVQIVP ==

Real power and Reactive power canbe controlled by regulating the magnitude, and the angle gL

II =

Pg= VIg cos Qg= VIg sin

Current Controlled VSI Fast current response Inherent current protection Appropriate for grid-

connected inverters such as for PV/Wind generators Hysteresis current

controller Ramp controller Predictive controller Current-based space vector

controller

Hysteresis Current Controller

Active and Reactive Power Control

PV/Grid Energy System Configurations

Large Single Inverter Type (Central Inverter)

Multiple Small Inverter Type (String Inverter)

DC Bus (Multi-string Inverter) AC Module

Large Single Inverter Type Series and Parallel

connection on DC side

All PV panels connected to single DC bus

Single Central Inverter

Affected by partial shading of panels

Only one protection system required

Multiple Small Inverter Type One inverter per

string Panels grouped into

smaller inverter rated power of Inverter ( 0.7-5kW)

Not so badly affected by shading

Not badly affected by inverter failure

@ 3.3kW

Grid-Connected PV Inverter (String Type)

Grid-Connected with Energy Back up System

Controller Back up Line

AC Grid Line

DC 48 V

AC Line

DC from PV

160 to 240 V

AC Line

DC 48 V

Grid-Connected PV System

with Back up Inverter

Kang Som-Mao, Ratchaburi

PV

CONTROLLER -

BATTERY batteries for S-218C

INVERTER APOLLO G 304 And S-218C

75 Wp x 42 modules

DC Linked

Each panel or group have a DC-DC step up converter

High voltage DC link feeds transformer-less converter

AC Modules

One Inverter per panel

High volume/ low cost?

Plug-and-play?

Wind Energy Conversion System

Wind

Wind TurbineRotor

Gearbox/Transmission Generator

Mechanical Power Electrical Power

PowerConverter

PowerTransformer

Electric Grid

Permanent Magnet PM Generator

GB

LAC

LDC

CDCVDC

Applications of Single-Phase Inverters for Small Wind Turbines

Wind turbine systemWind turbine system

AC/DC/AC Full Power Converter for Three-Phase Grids (PWM Rectifier)

Micro Hydro

Fuel Cells

Fundamentals and background

Energy Conversion Principle

Microgrid A MicroGrid power system

Is a local scale power system using distributed resources scaled to the local system demand.

Is designed to transfer seamlessly between connection with the local utility and isolated operation.

Benefits Improved power reliability and power quality Potential economic benefits: CHP, higher efficiency, diversified fuel

supplies Possible ancillary services for power system operators Transmission and distribution support in constrained areas. Potential for reduced emissions compared to centralized utility. Ability to allow high penetration of renewable generation.

Case study : The Republic of Maldives

1,192 islands with a land area of about 300 km2, formed on a chain of 26 coral reef atolls in the Indian Ocean

80 percent of the total landmass of the Maldives is less than 1 meter above sea level

Maldives Remote Islands

Uligam

Raimandhoo

Kondey

Advantages of the Renewable Energy Micro-Grid System

Can Provide 24 hours of Electricity Diesel Generator operating hours will be reduced which leads

to save in fuel plus O&M cost Reduced Cost of Electricity Fast pay back period [2-3 Years] Reduced noise and air pollution Reduced Greenhouse Gas Emission

+ ++ +

POWER ELECTRONICS

Micro Grid for Uligam lsland

Micro Wind Farm