I am looking to do a small project that is similar to generating electricity using a wind turbine. From my research I have found that most modern large scale wind turbines use permanent magnet synchronous generators, which seem to be relatively high cost. I am trying to understand if a BLDC motor would be the best option for generation in this project

The project would differ in a few key ways from modern wind turbines:

1.) Size - anticipated power needs between 500 W and 1,000 W
2.) RPM - rpm will likely be higher due to increased air speed (~ 100 MPH)
3.) Power output - consumed locally by DC equipment.

I am looking to maximize efficiency and at lowest cost. Any input or suggestions would be greatly appreciated

 

A BLDC motor can be used in an AC manner as it is the same construction as a AC PM motor.
i.e. It generates 3ph AC when back-fed.

 

I am looking to maximize efficiency and at lowest cost. Any input or suggestions would be greatly appreciated

Use simple induction 3-phase motor as generator.

 

Use simple induction 3-phase motor as generator.

Thanks - could you elaborate as to why. Are the cheaper and more efficient at high speeds compared to BLDC?

 

re the cheaper and more efficient at high speeds compared to BLDC?

The following table shows the results of 13 motors tested in Natural Resources Canada:

Three Phases 750W Induction Motor US $46

 

Another source used by some is a Fischer-Paykel BLDC out runner motor from scrapped washing machines.

 

If the rpm is higher than 3600 would you choose a different motor? Like wind turbines the rpm will not be constant and vary up to 20%. Would that change your motor selection from a 3 phase induction?

 

If the rpm is higher than 3600 would you choose a different motor? Like wind turbines the rpm will not be constant and vary up to 20%. Would that change your motor selection from a 3 phase induction?

In https://forum.allaboutcircuits.com/attachments/threephaseinductionmotorconversiontothree-pdf.280839/
they tested their motor from 1500 to 3600 RPM. Read please.

 

In https://forum.allaboutcircuits.com/attachments/threephaseinductionmotorconversiontothree-pdf.280839/
they tested their motor from 1500 to 3600 RPM. Read please.

Thanks for your input - I did read your article. However, the study didn't really compare generators. Instead it focused on the performance of an induction generator. They also didn't test higher than 3600 RPM.

Any input on the best generator type for the application I am describing would be helpful.