EEE598 – Renewable Electric Energy Systems
Raja Ayyanar
Lecture 1 – Introduction
http://us.sunpower.com/
http://www.eere.energy.gov/topics/wind.html
http://www.energy.gov/
Outline
Motivation, challenges in renewable energy
Present and projected capacity, cost and growth
Renewable energy portfolios and initiatives
Course organization, expectations and
major topic areas
This course is an advanced course in Power Electronics
and requires that the students have taken at least one
prior basic Power Electronics course and an
Electric Machines course. It involves extensive
power electronics and control simulations.
EEE598 – Raja Ayyanar
Motivation for Renewable Resources
• Environmental concerns: Greenhouse gas (GHG) emissions,
global warming
• Energy security concerns
• Depletion of fossil fuels
• Demand on water resources for electricity generation
• Electricity sector – increasingly transportation and
other electro technologies
EEE598 – Raja Ayyanar
Greenhouse gas effect
Current and projected energy resource mix
From: A. Sieminski: AEO2016 Rollout Presentation Johns Hopkins School of Advanced International Studies
June 28, 2016 | Washington, D.C
Current and projected electricity resource mix
From: A. Sieminski, “AEO2015 Rollout Presentation,” at Center for Strategic and International Studies
April 14, 2015 | Washington, D.C.
Renewable resource projection
From: A. Sieminski, “AEO2015 Rollout Presentation,” at Center for Strategic and International Studies
April 14, 2015 | Washington, D.C.
Issues in Widespread Use of Renewable Resources
•
•
•
•
•
•
Cost, capacity factor
Intermittency and uncertainty
Resources far from load centers
Mismatch between peak generation and peak load
Grid reliability under high penetration
Lack of utility scale storage
Source: http://my.epri.com/
EEE598 – Raja Ayyanar
Levelized cost of electricity (LCOE)
http://www.eia.gov/fore
casts/aeo/electricity_ge
neration.cfm
Data used in Annual
Energy Outlook
2015 (AEO2015)
RPS Policies
www.dsireusa.org / January 2011
WA: 15% x 2020*
MN: 25% x 2025
MT: 15% x 2015
(Xcel: 30% x 2020)
SD: 10% x 2015 WI: Varies by utility;
10% x 2015 statewide
NV: 25% x 2025*
IA: 105 MW
CO: 30% by 2020 (IOUs)
10% by 2020 (co-ops & large munis)*
CA: 33% x 2020
UT: 20% by 2025*
KS: 20% x 2020
RI: 16% x 2020
NY: 29% x 2015
CT: 23% x 2020
OH: 25% x 2025†
IL: 25% x 2025
PA: ~18% x 2021†
WV: 25% x 2025*†
NJ: 22.5% x 2021
VA: 15% x 2025*
MD: 20% x 2022
MO: 15% x 2021
AZ: 15% x 2025
OK: 15% x 2015
NM: 20% x 2020 (IOUs)
NH: 23.8% x 2025
New RE: 15% x 2020
(+1% annually thereafter)
x 2015*
5% - 10% x 2025 (smaller utilities)
ME: 30% x 2000
New RE: 10% x 2017
MA: 22.1% x 2020
MI: 10% + 1,100 MW
ND: 10% x 2015
OR: 25% x 2025 (large utilities)*
VT: (1) RE meets any increase
in retail sales x 2012;
(2) 20% RE & CHP x 2017
DE: 25% x 2026*
NC: 12.5% x 2021 (IOUs)
DC
10% x 2018 (co-ops & munis)
DC: 20% x 2020
10% x 2020 (co-ops)
PR: 20% x 2035
TX: 5,880 MW x 2015
HI: 40% x 2030
29 states +
Renewable portfolio standard
Renewable portfolio goal
Solar water heating eligible
Minimum solar or customer-sited requirement
*†
Extra credit for solar or customer-sited renewables
DC and PR have
an RPS
Includes non-renewable alternative resources
From: http://www.dsireusa.org/summarymaps/index.cfm?ee=0&RE=1
(7 states have goals)
RPS Policies with Solar/DG Provisions
www.dsireusa.org / January 2011
WA: double credit for DG
NH: 0.3% solarelectric x 2014
OR: 20 MW solar PV x 2020;
MI: triple credit for solar-
double credit for PV
NV: 1.5% solar x 2025;
2.4 - 2.45 multiplier for PV
MA: 400 MW PV x 2020
NY: 0.4788% customer-
electric
CO: 3.0% DG x 2020
IL: 1.5% PV
x 2025
UT: 2.4 multiplier
MO: 0.3% solarelectric x 2021
AZ: 4.5% DG x 2025
NJ: 5,316 GWh solar-
electric x 2025
1.5% customer-sited x 2020
for solar-electric
sited x 2015
OH: 0.5% solar-
NM: 4% solar-electric x 2020
electric x 2026
PA: 0.5% PV x 2021
DE: 3.5% PV x 2026;
WV: various
multipliers
NC: 0.2% solar
x 2018
DC
triple credit for PV
MD: 2% solar-electric x 2022
DC: 0.4% solar x 2020
0.6% DG x 2020
TX: double credit for non-wind
(non-wind goal: 500 MW)
16 states +
Renewable portfolio standard with solar / distributed generation (DG) provision
Renewable portfolio goal with solar / distributed generation provision
Solar water heating counts toward solar provision
From: http://www.dsireusa.org/summarymaps/index.cfm?ee=0&RE=1
DC have an RPS
with solar/DG
provisions
Growth in US Wind Power Capacity
http://awea.files.cms‐plus.com/Annual%20Report%20Capacity%20and%20Generation%202015.pdf
Growth in US Solar PV
http://www.seia.org/research‐resources/solar‐industry‐data
Solar installations in 2016
 In Q1 2016, the cumulative number of U.S. solar installations
exceeded 1million, representing 27.5 GWdc capacity [SEIA]
 In Q1 2016, solar accounted for 64% of all new electric generating
capacity added in the U.S. [SEIA]
 Estimated solar PV capacity to be added in 2016 – 14.5 GWdc [SEIA]
 Residential 3000 MW
 String 2500 MW - 500,000 inverters (5 kW rating)
 Micro 500 MW – 2M inverters (250 W)
 Commercial 1000 MW
 20,000 inverters (50 kW rating)
 Utility scale 10,500 MW
 21,000 inverters (500 kW rating)
Share of Wind/Solar in New Capacity Additions
Geographic spread of wind energy installations in US
Note: Numbers within states represent cumulative installed wind capacity and, in brackets, annual additions in 2014
From: R. Wiser, M. Bolinger, presentation on 2014 Wind Technologies Market Report, August 2015
PV Installations at ASU
•
Largest solar installation at a US university and largest non‐utility solar
power plant in AZ
Milestones as of August 1, 2015
Total Solar Generation Capacity: 24.1 MW
PV: 22.5 MW
Solar thermal: 1.6 MW equivalent
Total Solar Systems: 89
(77 on Tempe campus)
Total No. of PV Panels Installed: 81,424
https://cfo.asu.edu/solar
for information on each installation
Campus metabolism project at: http://cm.asu.edu/
for an interactive resource on the energy flow of buildings
including solar generation at all buildings over time
EEE598 – Raja Ayyanar
Impact of 1% higher efficiency with SiC/GaN
http://www.seia.org/research‐resources/solar‐market‐insight‐report‐2015‐q1
• Efficiency improvement with SiC is around 1%
‐ from about 96% to about 97% (string inverter)
• System level cost saving upfront to generate the
same amount of energy with1% smaller PV system
● For Q4 2014, the total PV system installed cost
is $3.54/W and the inverter cost is about
35c/W
● A 1.04% smaller PV system( i.e., 1/0.96) with
the SiC inverter will result in same energy
harvested but cheaper by 3.68c/W
● Comparing this to the 35c/W cost of the
inverter this works out to be 10.5% effective
cost saving
● This is in addition to the cost savings in BOM
due to smaller filters, enclosures, thermal
management
18
Power Electronics and Renewable Energy Systems
• Power conversion and conditioning
• DC to grid quality AC for PV
• AC‐DC‐AC conversion for wind system
• Power control for maximum power
• Ensuring grid interconnect requirements
• Grid support and mimicking conventional
generator characteristics (inertia)
• ‘Smart grid’ functions
• FACTS and other power control devices in
transmission systems
• Interface for various types of energy storage
including electric vehicles as storage, V2G
• Applications in energy efficiency measures
EEE598 – Raja Ayyanar
Major Course Topic Areas
• Power converters and control for PV systems
• Power converters and control for wind generators
• Grid integration of large‐scale wind and
solar resources
EEE598 – Raja Ayyanar
PV Systems
Power converters and control for PV
• Voltage source converters
• Overview of solar cells, characteristics and circuit models
• Topologies, principles of operation and design of single‐ and three‐
phase inverters for PV
• Harmonic analysis, power quality and filter design
• Current injection control at unity power factor, reactive power
control and smart inverters
• Maximum power tracking algorithms and implementation
• Anti‐islanding methods and interconnection standards ‐ IEEE 1547
• Steady‐state and dynamic models of PV systems and
implementation in simulation tools
• Project 1 is on PV inverter systems (due 10/18)
EEE598 – Raja Ayyanar
Wind Energy Systems
Power converters and control for wind generators
• Overview of wind turbine systems and configurations
• Steady‐state analysis of doubly fed induction generator
• Dynamic analysis of doubly fed induction generator
• Field oriented control of rotor side and grid side power
converters
• Control methods for maximum power extraction, active and
reactive power control
• Analysis and control of PMSM based wind generators
• Project 2 is on wind systems (due 11/29)
EEE598 – Raja Ayyanar
Grid Integration of large‐scale PV and wind
• Impact of high penetration of PV on distribution
system operation and control
• Transient operation with grid faults, and low voltage
ride through (LVRT) requirements for wind and
utility‐scale PV
• Grid support features of utility‐scale PV and wind
farms
• Microgrids, and frequency/voltage control in
islanded mode of operation
EEE598 – Raja Ayyanar
Course organization
Class Web page: http://myasucourses.asu.edu
• All lecture slides, class notes, homework assignments
and solutions posted on the web
• Discussion forums: Homework, general REES topics
Reference book: V. Vittal, R. Ayyanar, “Grid integration
and dynamic impact of wind energy” Springer, 2012.
Lecture slides, instructor notes, research/industry papers
Extensive simulation: PLECS/Simulink or other tools
(using individual student PLECS licenses)
EEE598 – Raja Ayyanar
Grading
Homework
2 course projects
Midterm exam
Final exam
> 95 A+
90-94 A
85-89 A-
EEE598 – Raja Ayyanar
15%
40%
15%
30%
(10/18 and 11/29)
(10/6)
(12/8)
80-84 B+
75-79 B
65-74 B- etc
Course projects
• Project 1: PV inverters and control system
• String inverter
• Utility-scale, three-phase inverter
• Microinverter
• Project 2: Wind energy converter and control
• DFIG wind generator
• PMSM wind generator
• Detailed design of power stage and various control stages
• Extensive simulation validation and correlation with analysis
• Formal technical report
• Teams of exactly 2 students, and different partners for the
two projects (online students may do the projects individually)
EEE598 – Raja Ayyanar
Power electronic converters
•
•
•
•
Voltage source or voltage link converters (VSC)
Current source or current link converters (CSC)
Matrix converters
Thyristor based self and line commutated converters
• Voltage source converters probably the most
widely used at present
• Characteristics of currently available
power semiconductor devices favor VSC
• We focus on VSC here and look at the basic
components of a generic VSC
EEE598 – Raja Ayyanar
Voltage source converters ‐ applications
• Voltage source converters encompass a wide spectrum of applications
•
•
•
•
•
•
Grid integration of photovoltaic and wind energy resources
Electric vehicle drive train and industrial motor drives
Battery management for wide range of applications and power levels
DC‐DC converters powering information technology, telecommunications
High frequency lighting
Power flow and power quality controllers in electric power systems
CREE LED lighting
EEE598 – Raja Ayyanar
VSC example: wind generator
Double PWM converter for doubly fed induction generator
EEE598 – Raja Ayyanar
Components of a voltage source converter
EEE598 – Raja Ayyanar
Closed loop controller
•
•
•
•
•
•
•
Implements various control and optimization algorithms
Processes various command and feedback signals
Generates the control voltage for the PWM block
Determines dynamic performance and stability
Supervisory and switch level controllers
Mostly digital ‐ DSPs, FPGAs, …
Communication with external systems
EEE598 – Raja Ayyanar
Pulse‐width modulator
•
•
•
•
Generates the switching signals for driving the power devices
Impacts switching losses and high frequency distortion
Carrier based methods (sine‐triangle comparison)
Space vector modulation methods for three‐phase
EEE598 – Raja Ayyanar
Power converter circuit topology
• Circuit configuration of various power semiconductor devices
(IGBTs, diodes), capacitors, inductors, transformer windings
• Power‐pole based topologies, with bi‐positional switch as a
building block
• Topology selection impacts functionalities, steady‐state and
dynamic performance, cost, power density
• Often a trade‐off between competing performance
requirements
• Circuit configuration should satisfy principles of switch mode
power conversion
EEE598 – Raja Ayyanar
DC link
C
VS
• VSC synthesize controlled low‐frequency or dc voltages in an average
sense by switching a dc voltage referred to as the dc link or dc bus
• DC link can be dc source (battery, rectified ac voltage source) or a large
capacitor
• DC link port can
• source power with a dc source
• Ex: Photovoltaic source to grid
• sink power with a capacitor and a load at the DC link
• Ex: AC to DC PWM rectifier with DC load
• have zero average power with just a capacitor
• Ex: STATCOM (static compensator used in power flow control)
EEE598 – Raja Ayyanar
External power system
• In general, a voltage source converter can interface multiple external power systems
(but often just two)
• External power system can represent AC or DC source(s), or AC or DC load(s)
• Examples include the power grid, machine windings, AC and DC load
• Power flow can be bi‐directional and role of source and load can vary dynamically
• Example: Charging or discharging of a battery, DFIG wind generator where
power flow direction can change depending on sub‐ or super‐synchronous mode
EEE598 – Raja Ayyanar
Example: Single phase PV inverter
EEE598 – Raja Ayyanar