Fractional Order Modeling

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Fractional Order Modeling Control Strategies
for Grid-Connected Renewable Energy Sources
Major Professor Dr. Chen Committee members
Dr. Cripps, Dr. Spencer, Dr. Wu and Dr.
Ban Presenter Hadi Malek Ph.D.
Student Electrical Computer Engineering
Department Utah State University 04/27/2012 Emai
l hadi.malek_at_ieee.org
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Outline

• New trends in power electronics for applying
  fractional order calculus (FOC) in grid-connected
  renewable energy systems.
• Advantages of using FOC.
• Review of the current system and recent
  researchers regarding applying FOC.

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Introduction

• Increasing number of renewable energy resources
  and distributed generators
• New strategies for the operation and management
  of the electricity grid
• Improve the power-supply reliability and quality

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Power-electronics technology

• Plays an important role in distributed generation
• Integration of renewable energy sources into the
  electrical grid
• Fast evolution, due to
• development of fast semiconductor switches
• introduction of real-time controllers

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New technologies - wind turbines

• Variable-speed technology 5 increased
  efficiency
• Easy control of active and reactive power flows
• Rotor acts as a flywheel (storing energy)
• No flicker problems
• Higher cost

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Wind turbine technology

• Wind-turbine market has been growing at over 30
  a year
• Important role in electricity generation
• Germany and Spain

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Rectifier and chopper
Energy Transfer Control of the active and
reactive powers total-harmonic-distortion control
Energy storage CONTROL of Vdc
driver controlling the torque generator, using a
vector control strategy
step-up chopper is used to adapt the rectifier
voltage to the dc-link voltage of the inverter.
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PV Photovoltaic Technology

• PV systems as an alternative energy resource
• Complementary Energy-resource in hybrid systems
• Solar-electric-energy growth consistently 2025
  per annum over the past 20 years
• 1) an increasing efficiency of solar cells
• 2) manufacturing-technology improvements
• 3) economies of scale

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PV growth

• 2001, 350 MW of solar equipment was sold 2003,
  574 MW of PV was installed.
• In 2004 increased to 927 MW
• Significant financial incentives in Spain,
  Germany, Italy and France triggered a huge growth
  in demand
• http//www.erec.org

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Perspectives

• World solar photovoltaic (PV) installations were
  2.826 GW peak (GWp) in 2007, and 5.95 GW in 2008
• The three leading countries (US, Germany,
  Japan) represent nearly 89 of the total
  worldwide PV installed capacity.
• In 2012, 12.3GW- 18.8GW (expected!)

http//www.renewableenergyworld.com
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Efficiency

• Market leader in solar panel efficiency (measured
  by energy conversion ratio) is SunPower, (San
  Jose USA) - 23.4
• market average of 12-18. (http//www.sroeco.com)
• Efficiency of 42 achieved at the University of
  Delaware in conjunction with DuPont
  (concentration) in 2007.
• The highest efficiency achieved without
  concentration is by Sharp Corporation at 35.8
  using a proprietary triple-junction manufacturing
  technology in 2009.

G. Pilawjian , Analysis of Photovoltaic
Concentrating Solar Energy Systems, ARPN Journal
of Systems and Software VOL. 2, NO. 3, March 2012.
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ON Grid OFF Grid
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Power-Quality Requirements for Grid-Connected RES

• Flicker interharmonics
• Anti-Islanding
• Voltage Fault Ride Through Capability
• Standards (IEEE, NEC, IEC, )

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Requirements
K. Fujii1, N. Kanao, T. Yamada1, Y. Okuma, Fault
Ride Through Capability for Solar Inverters,
Power Electronics and Applications (EPE 2011),
Proceedings of the 2011-14th European Conference
on , vol., no., pp.1-9, Aug. 30 2011-Sept. 1 2011

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Islanding

• Islanding is the continued operation of the
  inverter when the grid has been removed on
  purpose, by accident, or by damage
• Detection schemes - active and passive.
• The passive methods -monitor grid parameters.
• The active schemes introduce a disturbance into
  the grid and monitor the effect.

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Islanding
PV Generator Converter AC-DC Local
Loads Grid
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Standards

• Flicker analysis
• Switching operations. Voltage and current
  transients
• Harmonic analysis (FFT) - rectangular windows of
  eight cycles of fundamental frequency. THD up to
  50th harmonic

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Standards

• The standards
• EN61000-3-2, IEEE1547,
• U.S. National Electrical Code (NEC) 690
• IEC61727
• power quality, detection of islanding operation,
  grounding
• structure and the features of the present and
  future PV modules.

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Maximum Power Point Tracker
EX. ripple voltage should be below 8.5 of the
MPP voltage in order to reach a utilization
ratio of 98
S.B. Kjaer, Member, J. K. Pedersen, F. Blaabjerg,
A Review of Single-Phase Grid-Connected
Inverters for Photovoltaic Modules, IEEE
TRANSACTIONS ON INDUSTRY APPLICATIONS, VOL. 41,
NO. 5, OCT 2005
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High efficiency

• Wide range of input voltage and input power
• Very wide ranges as functions
• of solar irradiation and ambient temperature.

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Fractional Order Calculus

• Definitions
• Why Fractional Order Calculus?
• What have been done?
• Whats the plan?

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Fractional Order Calculus
Reimann-Liouville Definition
Caputo Definition
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Fractional Order Calculus

• Laplace Transform

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Fractional Order Calculus
I. Podlubny, Geometric and physical
interpretation of fractional integration and
fractional differentiation, Fractional Calculus
and Applied Analysis, vol. 5, no. 4, pp. 367
386, 2002.
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Fractional Order Calculus(Why?)

• Stability

Is BIBO stable if
Ivo Petras, STABILITY OF FRACTIONAL-ORDER
SYSTEMS WITH RATIONAL ORDERS A SURVEY,
Fractional Calculus Applied Analysis, Vol 12,
No. 3, 2009
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Fractional Order Calculus(Why?)

• Robustness

Y.Q. Chen, H.S. Ahn and I. Podlubny, Robust
Stability Check of Fractional Order Linear Time
Invariant Systems With Interval Uncertainties,
Proceedings of the IEEE International Conference
on Mechatronics Automation Niagara Falls,
Canada July 2005
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Fractional Order Calculus

• More Degree of Freedom
• Better Time Domain Specification

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Fractional Order Calculus(Why?)

• Nature of Input

Z. J. Ye X., Xia X. and Y.Q. Chen, Fractional
analysis and synthesis of the variability of
irradiance and pv power time series, in FDA,
(China), May 2012.
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Fractional Order Calculus(Why?)

• Nature of the System

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Fractional Order Calculus(Why?)

• Nature of the System

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Fractional Order Calculus(Done!)

• Wind Turbine

R. Melício, V.M.F. Mendes, J.P.S. Catalão,
Fractional-order control and simulation of wind
energy systems with PMSG/full-power converter
topology, Energy Conversion and Management,
Volume 51, Issue 6, June 2010, Pages 1250-1258.
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Fractional Order Calculus(Done!)

• FO Controller for Three Level MNP Inverter

K. Arab-Tehrani, T. Capitaine, Ludovic Barrandon
, M. Hamzaoui, S.M.R.Rafiei and A. Lebrun,
Current Control Design with a Fractional-Order
PID for a Three-Level Inverter FDA2012.
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Fractional Order Calculus(Done!)

• FO Controller for Three Level MNP Inverter

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Fractional Order Calculus(Done!)

• FO Controller for DC-DC Buck Converter

A.J. Calderon, B. V. Vinagre, and V. Feliu.
Fractional Order Control of a Power Electronics
Buck Converter. In Proceeding of the 5th
Portuguese Conference on Automatic Control 2002
(Controlo 2002), pages 365370, September 5th
Portuguese Conference on Automatic Control.
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Fractional Order Calculus (Feasibility!)

• Analoge Implementation

Gary W. Bohannan, Analog Realization of a
Fractional Control Element, October 27, 2002
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Fractional Order Calculus (Feasibility!)

• Digital Implementation

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Research Plan

• Grid-Connected PV System

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Research Plan

• Irradiation

http//www.mavericksolar.net/
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Research Plan

• FO MPPT

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Research Plan

• FO MPPT

http//www.mpoweruk.com
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Research Plan

• FO MPPT (Extremum Seeking Control)

M. Krstic H.H. Wang, Automatica, 36, 2000.
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Research Plan

• FO MPPT (Extremum Seeking Control)

Ref S.L. Brunton, C.W. Rowley, R.K. Sanjeev, C.
Clarkson, IEEE TRANSACTIONS ON POWER ELECTRONICS,
VOL. 25, NO. 10, OCTOBER 2010
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Research Plan

• Traditional Control Strategy

Zhang, Jianzhong Cheng, Ming , "DC link voltage
control strategy of grid-connected wind power
generation system," Power Electronics for
Distributed Generation Systems (PEDG), 2010 2nd
IEEE International Symposium on , vol., no.,
pp.970-975, 16-18 June 2010
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Research Plan

• FO DC Link Voltage Control

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Research Plan

• FO Current Control Loop

Romero-Cadaval, E. Milanes-Montero, M.I.
Gonzalez-Romera, E. Barrero-Gonzalez, F. ,
"Power Injection System for Grid-Connected
Photovoltaic Generation Systems Based on Two
Collaborative Voltage Source Inverters,"
Industrial Electronics, IEEE Transactions on ,
vol.56, no.11, pp.4389-4398, Nov. 2009
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Research Plan

• FO Current Control Loop

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Research Plan

• FO Filtering

K. Fujii1, N. Kanao, T. Yamada1, Y. Okuma, Fault
Ride Through Capability for Solar Inverters,
Power Electronics and Applications (EPE 2011),
Proceedings of the 2011-14th European Conference
on , vol., no., pp.1-9, Aug. 30 2011-Sept. 1 2011

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Research Plan

• FO Filtering

G. Shen, D. Xu, L. Cao, and X. ZhuAn, Improved
Control Strategy for Grid-Connected Voltage
Source Inverters With an LCL Filter, IEEE
TRANSACTIONS ON POWER ELECTRONICS, VOL. 23, NO.
4, JULY 2008.
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Plan

• Developing better fractional order models of
  inputs and converter devices such as DC/DC
  converters, Voltage Source Inverter (VSI) or
  Current Source Inverter (ISI) and storage
  devices.
• Developing better control techniques based on
  these newly developed models
• Dialyzing and comparing several modeling
  topologies and control strategies.

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Timeline
Irradiation Modeling Review current estimation methods. Applying FO estimation to experimental data and comparison with other methods 2 month
Boost Converter Design and Implementation of FO MPPT (Simulation) Analyses (Stability, ) tuning Performance Evaluation Comparison the efficiency 4 month
Inverter Review current control strategies Applying and tuning FO controllers to VSC and ISC analyzing the results (Simulation) Comparison with traditional strategies. 4 month
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Timeline
Filtering Apply tuning FO filters to the system Analysis (Stability, time domain specification, freq. domain specification, ) 2 month
Overall Design and Implementation of overall system with FO controllers and filters Analyses (Stability, Robustness, ) tuning Performance Evaluation Calculate and comparison the efficiency 2 month
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Thank You!

• Questions?