Dear Wiyam,

The advantages/disadvantages of the PMSG over the DFIG are as follows:

PMSG: Advantages- Modern, usually low speed so no gearbox, easy to control using a Variable Speed Drive Converter;

Disadvantages- Needs to be direct drive therefore large diameter & expensive, permanent magnets the generator cost, needs a fully-rated converter, increases cost of generator/converter combination;

DFIG: Disadvantages- Seen as old-fashioned, high speed so needs a gearbox;

Advantages- Straightforward established design, no PM Magnets so cost isssue is removed, needs only 1/3 Rated Converter lowering cost of generator/converter combination, in general cost of DFIG+1/3 RatedConverter+Gearbox is always cheaper than PMG+Full-rated Converter.

Regards

Peter Tavner

Dear Wiam,

You may have a look on paper:

Article Generator Systems for Marine Current Turbine Applications: A...

In work, a comparative study between the PMSG and the DFIG for marine applications. the study can be extended for wind applications.

I am attaching the paper.

Regards,

Mohamed

Dear Mohamed Benbouzid ,

Thank you so much for sharing the paper ^^

Dear Wiam,

You may have a look on paper:

Article Comparative small-signal stability analyses of PMSG, DFIG- a...

Dear Wiyam,

The advantages/disadvantages of the PMSG over the DFIG are as follows:

PMSG: Advantages- Modern, usually low speed so no gearbox, easy to control using a Variable Speed Drive Converter;

Disadvantages- Needs to be direct drive therefore large diameter & expensive, permanent magnets the generator cost, needs a fully-rated converter, increases cost of generator/converter combination;

DFIG: Disadvantages- Seen as old-fashioned, high speed so needs a gearbox;

Advantages- Straightforward established design, no PM Magnets so cost isssue is removed, needs only 1/3 Rated Converter lowering cost of generator/converter combination, in general cost of DFIG+1/3 RatedConverter+Gearbox is always cheaper than PMG+Full-rated Converter.

Regards

Peter Tavner

Dear Prof. P.J. Tavner,

Thanks for your answer. P.J. Tavner

Dear Prof P.J. Tavner thank you so much for your answer.

Dear all, in my opinion, the scheduled maintenance of the machine is one of the important factors to discuss in comparing the PMSG and the DFIG. regardless of the converter type, the larger the machine, the more difficult to maintain when necessary. Construction of large PM machines in general would be difficult and expensive compared to DFIG when considering the attraction forces of PMs, therefore maintenance would also be so. I hope one can support this point by providing an article in this field. However, gearbox in large DFIG might also have maintenance issues. A paper would also be useful in this field.

Many thanks to all of yous.

Aslan Jalal

Dear , as i have worked via the two machines the PMSG advantages compared to DFIG are,

-we can avoid using a gear box on the case of PMSG

-the facility of control compared with DFIG where it has to make decoupling power control on rotor side

-Auto excitation for PMSG

Greetings!

In which point of you you'd like to know ? I think it depends on the environment of use (offshore/onshore) , also wind's vein So that the installation's dimension.

As known, regarding the conversion wind power sys-

tems, the doubly-fed induction generator (DFIG) is

widely used regarding its several advantages such as: op-

eration at variable speed, four quadrant active and reac-

tive power capabilities, compared with fixed speed in-

duction squirrel cage and synchronous generators, its

bidirectional converter is designed to handle about

±25 % of the generator rating, among others.

Kindly you find in the attached file a description of the different generator/topologies limits.

Hope that'll be useful for you,

Regards!

Many thanks to all of you. You helped me a lot ^^

Thank you Nusrat Husain

DFIG Advantages

- control reactive power without using capacitor

- converters need only 20-30% of rated power (i.e Low loss)

- Maximum power extraction

- Power factor control