Integration of Green Energy in Distributed Generation Systems

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Integration of Green Energy in Distributed
Generation Systems
Ali KeyhaniProfessor of Electrical and
Computer Engineering Ohio State University,
Columbus Ohio Keyhani.1_at_osu.edu
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Distributed Generation Systems
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Introduction (1)

• Distributed Energy Sources
• Photo voltaic Energy
• Wind Energy
• Fuel Cells
• Micro Turbines
• Storage Devices

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contains a 100W solar panel, a 12V battery and a
charge controller, and a 12VDC/220VAC power
inverter.
100 W Solar Photo Voltaic Energy Source


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(No Transcript)
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• What is a fuel cell?
• A fuel cell is an electrochemical energy
  conversion device that converts hydrogen and
  oxygen into electricity and heat
• Potential to truly revolutionize power generation
  by virtue of their inherently clean energy
  generation.

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Introduction (2)

• How does a fuel cell work?
• Produce power electrochemically by simultaneously
  passing a hydrogen-rich gas over an anode and air
  over a cathode.
• By introducing an electrolyte in between the two,
  an exchange of electrical charges occurs -- ions.
  
• Hydrogen reacts with oxygen, causes one or the
  other stream to become charged, or ionized.
• The flow of ions through the electrolyte induces
  an electric current in an external circuit or
  load.

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Introduction (3)

• How does a fuel cell work?

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Introduction (5)

• Our role in fuel cell applications-Energy
  Conversions for
• Distributed generation
• With or without utility interfacing
• Power supplies for critical loads
• Automotive
• Zero-emission vehicles
• Unlimited business opportunities

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Control of Fuel Cell Generating Source
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FC Energy Conversion System Development Issues
(1)

• System configuration and auxiliary source

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Low Voltage Distributed Generation Systems
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FC Energy Conversion System Development Issues (4)

• DC/AC conversion
• 3-phase or single phase
• Voltage regulation (steady state)
• THD
• Transient response
• Overload protection
• Robustness to various disturbances

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DG/UPS

• DG ensures continuous power delivery for critical
  loads such as computers, servers, communication
  equipment, and other critical processes.
• During emergency (utility outage) maintains power
  to the load Some DGS also provide regulated
  voltage to the load at all times.

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Transportation

• A typical system

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Emerging Systems Advanced Braking

• Brake By Wire
• Advanced silicon and fault tolerant protocol
• Provides increased features for total stability
  control
• Advanced vehicle dynamics through integration of
  cruise control and braking systems
• CPUs, Power, and Intelligent Sensors

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Emerging Systems Hybrid Engines

• Advanced control, 42V/14V power system and Fifth
  Wave products
• DSP cores for vector control
• Power and products for high power battery control
• Intelligent Sensors for temperature and position
• Dependable real-time bus

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HEV block diagram
DSP system
Engine Timing Control Signals
IC Engine
Engine Control Unit
High voltage battery -
DSP system
Supervisory Controller (Vehicle Control
Unit) Transmission and Clutch Controller)
Electric Machine Control Unit(EMC)
PWM
Motor/Generator
Power converter
Voltages and currents
DSP system
Torque/Speed/ Position sensors
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Three-phase IGBT PWM Inverter

• Research focus Digital Control of the PWM
  Inverters for On-Line DG/UPS

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Issues in paralleling DG/UPS

• To be avoided
• Unequal loading
• Circulating currents
• Due to the presence of
• Component mismatches
• Measurement Errors
• Mismatch wiring impedances
• Undesirable
• Increased system losses
• Decreased total capacity (need to de-rate the
  units)

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Research Problems

• Single Unit PWM Inverter Control
• Propose a novel control using Perfect Robust
  Servomechanism Problem
• (Perfect RSP) Voltage Controller and
  DiscreteSliding Mode Current
• Controller to achieve
• good voltage regulation
• good THD
• good transient response
• and fast current limiting

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Research Problems

• Parallel PWM Inverters Control

• Develop load sharing technique that improves
  prior works in
• The proposed technique shall attempt to
  eliminate, if not reduce the absolute dependency
  on inter-communication between units to guarantee
  proper load sharing.
• The technique shall not be sensitive to the
  following component mismatches, measurement
  error, or unbalanced load or wire impedances.
• The proposed technique shall attempt to establish
  the sharing of harmonic components of the
  currents, without significantly degrading the
  performance of the outputs voltages.
• The proposed technique shall attempt to avoid the
  existence of a single point failure in the
  paralleled units configuration, such as a
  master/slave actions and common synchronization
  signals

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Research Tasks
Analysis, design, development through
simulations and experimental works
2 x 5 kVA Experimental Setup
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Literature Reviews Control of Single PWM
Inverters Techniques for achieving low THD

• Earlier techniques were PWM generation based
• Carrier modulated PWM techniques
• Preprogrammed optimized PWM

Average RMS Voltage Regulation
PWM pulses generation
PWM Inverter
Modulation index
Optimized PWM patterns

• Slow responses to load transients

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Literature Reviews Control of Single PWM
Inverters Techniques for achieving low THD

• Real time Pulse-by-pulse digital Control
• Decoupled PI Control
• Deadbeat control
• Sliding Mode Control

• Good transient response, but high THD on
  non-linear loads

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Proposed Single Unit Control

• Perfect Robust Servo Mechanism Voltage Controller
  and Discrete Sliding Mode Current Controller

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Development of Single Unit Control

• State space model of the plant in DQ Stationary
  Reference Frame

• Zero Components are uncontrollable, not
  considered for control design

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Development of Single Unit Control

• Design Steps
• Obtain the discrete plant model
• Design Sliding Mode Current Controller
• Include dynamics of the Sliding Mode Current
  controller as the plant for the Voltage
  Controller
• Design the Perfect RSP Control
• Include necessary harmonics to be eliminated
• Compute the gains by minimizing PI

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Related Refrences

• M.N. Marwali and A. Keyhani, Control of
  distributed generation systems, part I voltages
  and currents control, IEEE Transactions on Power
  Electronics, Vol. 19, No.6, pp 1541-50, Nov.
  2004.
• M.N. Marwali, J.W. Jung, and A. Keyhani, Control
  of distributed generation systems, Part II Load
  Sharing Control, IEEE Transactions on Power
  Electronics, Vol. 19, No.6, pp. 1551-61, Nov.
  2004.
• Jung, J.W. Dai, M. Keyhani, A., Optimal
  control of three-phase PWM inverter for UPS
  systems, IEEE 35th Annual Power Electronics
  Specialists Conference, Vol. 3, pp. 2054-59,
  2004.
• Min Dai, Mohammad N. Marwali, Jin-Woo Jung, and
  Ali Keyhani, "Power Flow Control of a Single
  Distributed Generation Unit with Nonlinear Local
  Load," IEEE Power Engineering Society 2004 Power
  Systems Conference and Exposition, Vol.1, pp.
  398-403, Oct. 2004..
• Jin-Woo Jung and Ali Keyhani, "Control of a Fuel
  Cell Based Z-Source Converter", IEEE Transaction
  on Energy Conversion, volume 22,  issue 2,  June
  2007 Page(s)467 - 476 Digital Abstract PDF
  Full-Text (1.10MB) 
• .Mohammad N. Marwali, Jin-Woo Jung and Ali
  Keyhani, "Stability Analysis of Load Sharing
  Control for Distributed Generation Systems", IEEE
  Transactions on Energy Conversion, Vol. 22, No.3,
  September 2007, pp. 737-745 Abstract PDF
  Full-Text (1.13MB)
•  

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• Mohammad N. Marwali, Min Dai, and Ali Keyhani,
  "Robust Stability Analysis of Voltage and Current
  Control for Distributed Generation Systems," IEEE
  Transactions on Energy Conversion, Volume 21, No.
  2, June 2006, pp. 516-526. Abstract PDF
  Full-Text (499KB)
• Min Dai, Mohammad N. Marwali, Jin-Woo Jung, and
  Ali Keyhani, "Power Flow Control of a Single
  Distributed Generation Unit with Nonlinear Local
  Load," IEEE Power Engineering Society 2004 Power
  Systems Conference Exposition, October 10-13,
  2004, New York city, NY Abstract PDF Full-Text
  (805KB)
•  Min Dai, Mohammad N. Marwali, Jin-Woo Jung, Ali
  Keyhani, Fellow, A Three-Phase Four-Wire
  Inverter Control Technique for Single Distributed
  Generation Unit in Island ModeIEEE Transaction
  in Power Electronics. In Print 
• Min Dai, Mohammad N. Marwali, Jin-Woo Jung, and
  Ali Keyhani, "Power Flow Control of a Single
  Distributed Generation Unit with Nonlinear Local
  Load," IEEE Power Engineering Society 2004 Power
  Systems Conference Exposition, October 10-13,
  2004, New York city, NY Abstract PDF Full-Text
  (805KB)
• http//www.ece.osu.edu/facultystaff/keyhani.htmht
  tp//eewww.eng.ohio-state.edu/ems
•