This document discusses a novel integrated AC/DC/AC converter for direct drive permanent magnet wind power generation systems. It aims to reduce switching losses and circulating current in the power converters used. The proposed method uses a 9-switch converter topology compared to 24 switches typically used. This reduces switching losses, minimizes circulating current, improves power factor and overall performance. The converter contains a Vienna rectifier, DC link, and 6-switch voltage source inverter to stably convert variable AC to AC with improved efficiency.

1. A NOVEL INTEGRATED AC/DC/AC CONVERTERS FOR DIRECT
DRIVE PERMANENT MAGNET WIND POWER GENERATION
SYSTEM
by
SHEELA AROKIA MARY . J
M.E ( EMBEDDED SYSTEM TECHNOLOGIES)
Under the Guidance
Of Mr.S.Sivasakthi M.E.,
Associate Professor
Head of the Department
Department of EEE

2.  To reduce the switching loss & Minimize the
circulating current in the power converters used in
Wind power generation system and to improve the
Power factor & overall performance of the system.

3.  24 switches are used in Power converters.
 Separate stabilizing circuit is used
 Switching losses are high
 Presence of Harmonics are high

4.  9 switches are used.
 Switching losses are reduced.
 Circulating current is minimized.
 Less harmonics.
 Power factor improvement is made.

5.  This proposed system has AC/DC/AC converter.
 In existing ac-ac converter topologies, 2 level 6 switch
comprising a common dc link capacitor & VSI are
frequently used
 In order to minimize the switching loss , we are
implementing a topology of 9 switch USMC for wind
energy conversion system.
 For rectification, a 3 switch Vienna rectifier is used.

6.  In inverter stage it employs an 6 switch VSI.
 Hence the number of switches & switching losses are
reduced.
 The circulating current is minimized & Power factor
improvement is made.
 As a result harmonics are reduced & overall efficiency
is improved.

7.  PWM using PI Controller Technique.

9.  It converts wind energy into mechanical energy.
 Types – horizontal axis wind turbine & vertical axis
wind turbine.
 Efficiency & Power generation of wind turbine
depends on increase in height of the tower & speed of
the wind.
 Direct drive- Generator directly coupled with turbine.

10.  It converts the mechanical power output of wind
turbine into electrical power.
 Principle-Faraday’s law of electromagnetic induction.
 Can be extremely large – power ratings up to 1500MW
 They are known as synchronous machines because
they operate at synchronous speed (speed of rotor
always matches supply frequency)Ns=120 f/p.
 Instead of field winding, permanent magnet is used.
 Does not require DC supply, Condenser not needed.
 So output power is fully utilized and total loss is
reduced, higher efficiency.

11. 3 phase AC
source
LC Filter
Solid
state
switches
Diodes &
capacitive
circuits
DC
Link
Micro
controller
based pulse
signal

12.  Unidirectional 3phase AC/DC converter.
 3 power switches.
 PF improvement
 Harmonics are reduced.

15.  9 switches.
 Converts unstable AC to stable AC voltage.
 Switching loss is reduced
 Circulating current is minimized.
 Overall efficiency is improved.

18.  MATLAB- Simulink
SOFTWARE REQUIREMENTS
 Microcontroller
 Inductor
 Controlled rectifier
 Inverter
 Gate driver

26.  Power factor
 Disadvantages of lagging power factor
 PF improvement equipments
 Power triangle

31. This paper has comprehensively addressed the
mimization of circulating current and switching losses.
In this method the unstable AC voltage is converted to a
stable AC voltage with power factor improvement.
Experimental verification of the power converters
confirms the good performance and promising features
of the proposed directly driven permanent magnet wind
power generation system.

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