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.,M.B.A.,

Associate Professor

Head of the

Department

Department of EEE

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.

24 switches are used in Power converters.

Separate stabilizing circuit is used

Switching losses are high

Presence of Harmonics are high

9 switches are used.

Switching losses are reduced.

Circulating current is minimized.

Less harmonics.

Power factor improvement is made.

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.

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.

PWM using PI Controller Technique.

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.

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.

3 phase AC

sourceLC Filter

Solid

state

switches

Diodes &

capacitive

circuits

DC

Link

Micro controller

based pulse

signal

Unidirectional 3phase AC/DC converter.

3 power switches.

PF improvement

Harmonics are reduced.

9 switches.

Converts unstable AC to stable AC voltage.

Switching loss is reduced

Circulating current is minimized.

Overall efficiency is improved.

MATLAB- Simulink

SOFTWARE REQUIREMENTS

Microcontroller

Inductor

Controlled rectifier

Inverter

Gate driver

Power factor

Disadvantages of lagging power factor

PF improvement equipments

Power triangle

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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hydro hybrid system using cage generators & battery

storage,”IEEE Trans.Ind.Electron., to appear.

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multi-MW wind turbines & wind parks,”IEEE

Trans.Ind.Electron.,vol.58,no.4,pp.1081-1095,Apr.2011.

A.Rajaei,M.Mohamadian,S.M.Dehghan,&A.Yazdian,”PMSG-

based variable speed wind energy conversion system using

rectifier,”Euro. Trans.Electr.Power,vol,21,Jan 2011