UTILIZA

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UTILIZAÇÃO DE PFCS EM SISTEMAS DE CONVERSÃO DE
ENERGIA EÓLICOS NA MINIMIZAÇÃO DE HARMÔNICOSC u
r t i n P U C R S

• Reinaldo Tonkoski Jr., Fernando Soares dos Reis,
• Jorge Villar Alé and Fabiano Daher Adegas
• Pontifical Catholic University of Rio Grande do
  Sul - Brazil
• Syed Islam and Kelvin Tan,
• Curtin University of Technology - Australia

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2.4 MW Power Plant in the Northest
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4.8 MW Power Plant in the South (8 x 600 kW)
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5.0 MW Power Plant in the Northest 10 x 500 kW
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Table of Contents

• Introduction
• Objectives
• Power Quality
• Harmonic Characterization
• The Harmonic Mitigation Schemes
• Power Losses
• Conclusions

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INTRODUCTION

• Permanent magnet synchronous generators (PMSG)
  wind energy conversion system (WECS) using
  variable speed operation is being used more
  frequently in wind turbine application. Variable
  speed systems have several advantages over the
  traditional method of operating wind turbines,
  such as the reduction of mechanical stress and an
  increase in energy capture. To allow the variable
  speed operation of the PMSG WECS a conventional
  three-phase bridge rectifier (BR) with a bulky
  capacitor associated with voltage source current
  controlled inverter (VS-CCI) is used.

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INTRODUCTION

• This simple scheme introduces a high intensity
  low frequency current harmonic content into the
  PMSG and consequently increases the total loses
  in it. Subsequently, decreases the power
  capability of the system. This work presents a
  comparative simulation study between three
  different approaches applied to harmonic
  mitigation on PMSG WECS. The studied techniques
  are a) harmonic trap filters (HTF), b)
  single-switch three-phase boost rectifier (PFC)
  and c) PWM Boost Rectifier.

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Turbinas de 10 a 100 kW
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WECS Wind Energy Conversion System
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Line-commutated inverter
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Current controlled inverter
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AC-DC Conversion
Loss Reduction
The Bridge Rectifier increases the losses.
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Power Quality

• The power quality concepts are well established
  and Widely applied in the relationship between
  utility and consumer
• Because it allows the maximization of the energy
  resources
• But these concepts were not normally applied to
  WECS once there are studies showing that the
  system efficiency is practically the some with or
  without harmonics in the PMSG.

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Harmonic Characterization
It seems O.K.
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Harmonic Characterization
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The Harmonic Mitigation Schemes

• Passive Harmonic Trap Filters (HTF)
• Single-Switch Three-Phase Boost Rectifier
• Three-Phase Boost type PWM Rectifier (AC-DC
  converter)
• Active Power Filter

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Passive Harmonic Trap Filters (HTF)
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Harmonic Trap Filters
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Using HTF for the 5th and 7th harmonic
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Using HTF for the 5th and 7th harmonic
PMSG output current
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Using HTF for the 5th and 7th harmonic
PMSG output voltage
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Single-Switch Three-Phase Boost Rectifier
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Single-Switch Three-Phase Boost Rectifier
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Three-phase PMSG output currents
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Three-phase bridge rectifier input currents
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PMSG output current
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PMSG output voltage
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Three-Phase Boost type PWM Rectifier
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Three-Phase Boost type PWM Rectifier
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Three-Phase Boost type PWM Rectifier IGBT
Diode current
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Three-Phase Boost type PWM Rectifier input
currents
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PMSG output current
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Power Losses

• PMSG losses
• Bridge Rectifier Losses
• Harmonic Trap Filter Losses
• Semiconductor Losses
• Mechanical losses

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PMSG losses reference circuit
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PMSG losses
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PMSG losses
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Conclusions

• In this work three well-known harmonic mitigation
  solutions were applied to PMSG WECS AC to DC
  conversion. They were the HTF, the PFC and the
  PWM Boost Rectifier. Harmonic trap filters are
  easily implemented by passive components but they
  are normally implemented with bulk components.

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Conclusions

• Notwithstanding the HTF had presented the good
  THD results they are not the best solution once
  they are a matched solution for a specific
  operation point (wind speed and output power).
  The losses study also has demonstrated that the
  PMSG efficiency (?) remains practically constant
  and the system efficiency (?) is the lowest when
  the HTF are used.

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Conclusions

• For these reasons, the HTF are not a recommended
  way out to obtain harmonic mitigation on PMSG
  WECS. On the other hand, the single-switch
  three-phase boost rectifier has presented
  encouraged results. Such as low current and
  voltage THD, simple power topology and control
  circuit, can work in all wind conditions and
  presents a real reduction of the PMSG total
  losses.

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Conclusions

• The PWM rectifier was studied once with this
  complex converter is possible to obtain ideal PF
  and THD. But the losses study has show results
  very closed to that obtained with the Single
  Switch Boost Converter. The main advantage is
  that with this converter is possible to work with
  output voltages around 600V in spite of 1000V.

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Conclusions

• Which allow expecting an increasing in the PMSG
  lifetime without reduction of the power
  capability. The main drawbacks of this topology
  are a) the conduction losses in the BR diodes and
  switch Q1 since the high RMS current value caused
  by the DCM operation and b) the high output
  voltage 1 kV. Both problems could be minimized
  using proper diodes and switch like IGBT.

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THANK YOU!