The 3 phase pump motor needs the voltage and frequency ratio to match as you change speed. Meaning if you have a 208VAC motor rated at 60Hz and you wanted to run at half speed, you would feed the pump motor 104VAC at 30 Hz. At 1Hz you would feed the motor 3.47VAC.
Why not design the wind turbine to provide this exact ratio of voltage to frequency directly to the pump motor. If the wind speed is slow, you may have problems pumping against such a large head. However, if the wind was blowing hard the pump would have all the power the turbine could provide with no loss in any voltage conversions.
Because you do not want to "store" water rather than electric power this may be a way to not need the VFD or batteries all together.
Just an idea to try. ---------Dean-----------[ Parent ]
I think we can rewire the alternators to achieve higher voltages as needed. I am interested in your #2 option (turbine>battery bank>dc bus of vfd). These would need to be deep cycle batteries? If there was a way to configure the vfd to only use the amount of power that the wind turbines were putting into the bank then maybe the expensive deep cycle batteries would not be needed. Or maybe at least not as high Ah ratings. I mean, only power the pump when power is coming in, and then, only to match (slightly under) what is coming in. How would I regulate this? I guess I had been sizing the battery bank for the pump like you might size one for any other appliance, giving sufficient Ah capacity to ensure power is provided for some time when the wind isn't blowing. But there is a large reservoir for the water. Much, much less might be spent on the batteries if the pump were only to be powered when the turbine is producing, and hopefully, somehow, to match that output. That may have been obvious to everyone else!
Cheers.
1996 A Smart Controller for Wind Electric Water Pumping Systems 2000 Development and Testing of a 2-Kilowatt Wind Turbine for Water Pumping[ Parent ]
