Quote:
Originally Posted by Josh8loop
Fellas,
This is really intersting stuff! I have a small wind turbine at my house that is based on a PMA(Permanent Magnet Alternator). It is more efficient than it's rotor excited counterparts such as car alternators that use up to 30-50 watts to get going. The only issue I have had with mine is that the voltage varies with rotor RPM which is to be expected of course. I am using very low voltage drop Schottkey diodes to rectify the 3 phase output to DC.
|
Just as a side note I am seeing about 1/2 of a Volt increase over Low Forward Voltage Drop (LFVD) Schottky diodes alone. As power is equal to Volts squared over resistance you might find this circuit very attractive. Right now in my circuit for a vehicle I'm finding you don't want to use MOSFETS with more than 50 nano Culombs of Gate charge. In a windmill application with lower RPM you could probably get away with more.
Quote:
|
Since the DC voltage varied so much, I needed a way to tame it and make it usefull. I ended up finding some DC-DC converters on Ebay that have the unique ability to take anywhere from 18-75 Vdc and put out a constant user adjustable voltage output. Overall the system works quite well. I wonder if rectifying the car alternator output with some low voltage drop diodes(like mentioned above) and coupled with using DC-DC converters could reduce the alternators efficiency a bit?
|
I think you mean improve its efficiency
The only problem I see with your plan is that by changing a standard alternator to a permanent magnet rotor is it will always try to generate as much power as it can. The DC to DC converter will have to waste some of it to throttle it down.
Actually there are permanent magnet alternators. They can get the efficiency into the mid to high 80% range. They are of course much more expensive and complicated.