I recently designed and built a water pumping system that runs on solar.
It provides over 34000 liters/day into a 110 psi head. (mostly sunny day ) On average, it keeps up this output in summer (cows don't need that much in winter) It puts out an awful lot on cloudy days as well...
Diode isolate the turbine DC and the panel DC, and run on both??
It uses the home brew solar panels (here )
http://fieldlines.com/board/index.php/topic,145005.0.htmlSo for only $1500 we had about 1.6kw or so of solar cells. (another good project for your builders)
It drives a curtis golf cart PWM controller good for 270 amps @ 36v $250 from ebay (USA)
The brush motor is from an old floor scrubber 2800rpm 2hp 36v costs nothing as a general rule............. generally thrown out by the service mobs. The ones from ADVANCE floor scrubbers are the best .... and always good for another 20 years..
The interesting part is the controller for the curtis. It involves some resistors, 2 opto isolators and a zener diode,.(maybe a dollar for the whole board)
Thats less than two grand for a village system ( you have the pump already ... just match the pulley ratio for your load/rpm) that will beat your current setup into next week I suspect
The same controller/curtis/motor set up could be as easily used with your turbine. It simply measures the input voltage, and if it is less then 33v or whatever you set for, it turns the pwm off, as it gets over 33v it pulls in the pwm. simple.... no it is not too harsh. You can control max speed by using different resistors across the pot input to the controller.
This was to replace a commercial (MONO) high tech pump system.... $30000.00. This system is easily it's equal...... and easily expandable (build more panels)
It was designed so that all the bits were cheap to get if they failed, and could be put together by anyone.
Your current high tech solution is the reason this was developed. People were sick of buying expensive goodies that failed, and then they were held hostage. There are no shops down the road here... your on your own..... not even a bazaar, or a bloke in a container to rewind your motor.
If you stick to your VFD, perhaps just find the star point and change the motor to delta instead of star. This will give you a three phase 240v motor from a 415v one.... simple.
If it was 415 in delta, you have some coils grafting to do....... but I see this route ending in tears..... just too much to go wrong.
Ditch the windmills and build solar panels.... probably cheaper and way more reliable in the hands of neophytes ..... these folks in Africa are doing it similarly to me
www.mainesolar.org/EVA.pdf.............oztules