Permanent Magnet Generators for Renewable Energy

Permanent Magnet Generator for Renewable Energy

The rate of depletion of conventional energy sources is increasing day by day.

This has affected the application of non-conventional energy sources over conventional. The renewable energy sources such as wind, solar, small scale hydro power plants, biogas etc. also provide better environmental protection.

With global energy shortages and depletion of fuel resources combined with fuel’s increasing cost, there is increasingly interest for alternative or renewable generators. New technologies are being sought to harness the resources efficiently and reliably with being cost-effective.

PMG Classification

Permanent magnet generators are categorized on basis of structure and direction of flux path;

 

i. Radial-flux permanent magnet machines (RFPM)

ii. Axial-flux permanent-magnet machines (AFPM)

iii. Transverse-flux permanent-magnet machines (TFPM)

 

Features of Permanent Magnet favoring Renewable Sector

 

• High Efficiency and Power Factor

 

More efficient and reliable energy conversion methods are constantly being sought for renewable energy applications. The permanent magnet is a concept that offers the feature. Other advantages include their relatively better power factors than other energy sources.

 

 

• Direct-Drive

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A chief application of variable speed generator is for wind turbine. Many small systems utilize direct-drive as they operate at high turbine speeds. Direct-drive can also be used in large turbines.

 

• Low Maintenance

PM machines do not require power electronic tools or gearboxes. Maintenance is thus reduced.

 

 

Unlike the Induction generators (IGs), the PMGs can be built with large diameters and high pole numbers.

They offer many benefits such as their brushless feature, ruggedness, easy maintenance, protection against short circuits and heavy overloads, etc.