Position-switched three-phase full-wave active rectification

[Boloar]

Idea: Position-switched three-phase full-wave active rectification

Here's a thought that passed through my head.

My boss works with vertical-axis wind turbines. He has them hooked up to three-phase alternators and a typical diode-bridge rectifier for DC output.
To increase efficiency a bit, one would try active rectification, but I don't think there are any active rectifier products that would be worth the cost for such low-power systems, and much less 3-phase.

The thought is: would it be feasible to set up MOSFETs that would switch on/off based on the physical rotation angle of the alternator? Say, using a Hall-effect sensor trigger or something?

 

[chuckey]

Starting from my dismal knowledge, I believe that for wind turbines there is an optimum rotation speed for every wind speed (for conventional turbines its pitch speed should be 2/3 of wind speed). If you just operate the alternator into an open circuit, this is the same as no diodes or your controlled diodes being switched off. So surely it would be better to leave the diodes in and switch the load using a pulsed series transistor. Depending on the current, going from the control input (anemometer?) to the switched transistor would only involve £10 worth of components.
Frank

 

[FvM]

An active rectifier can be controlled without sensors just based on generator voltage.