Frequency Signal Generator

[Rob Littiken]

Has anyone built their own Frequency Signal Generator for the Power One inverter or are most people just using the the DC output voltage from the rectifier?

[Jonathan Kraidin]

I convert the three-phase to DC and use this for the programmable wind table. Francesco, their tech for the device, says it is a more reliable method so I did not go there.

[Rob Beckers]

DC voltage works fine. There are a few turbine manufacturers that specify frequency vs. power, Eoltec being one of them. Haven't had any problems with that either. Mel is using frequency vs. power for his Excel-S, and he does currently have an issue that may be inverter related; it's blowing fuses in his PVI-Wind-Box'es, even though the table is such that it should never exceed the fuse limits. So, maybe there is an issue where the inverter has some type of dynamic behavior where it occasionally draws more current then it should in frequency mode.

Keep in mind that in frequency mode you basically give the inverter free reign as far as current is concerned. If for some reason the voltage is lower than expected, the inverter will simply ramp up the current as needed to reach the set output power, up to 36A. In voltage mode it can't do that; Current = Power / Voltage in the table.

The bottom line: Unless you need frequency mode for some reason I would stick with voltage mode. It works well, it works reliably, and it is much easier to 'see' what the inverter is doing (DC voltage is displayed on the front panel).

-RoB-

[Rob Littiken]

Yes. I think I'll keep it voltage for now and if I ever need it I'll build a Freq Gen.

Thanks for your input.

Rob L