OK, I actually got curious and looked at the SMA manual for Windy Boy:
http://www.sma-america.com/ftp/Windy%20Boy%20Operation%20Manual%20Addendum%20V12.pdf
Did not read as bad as I feared.
Page 3 says:
"Background
Historically, grid tied wind turbines have charged batteries through a charge controller and used another converter to process power from the battery to the utility grid. The dual conversion and inherent losses associated with moving power through a battery resulted in very inefficient delivery of wind power to the utility. Overall transfer/conversion losses were easily in the 40-50% range. This means that 50% of the energy available from the wind turbine was being delivered to the utility.
The Windy Boy inverter is a single conversion, DC to AC inverter, which is similar in operation to the Sunny Boy grid tied PV inverter. Mechanical power from the turbine is delivered to the inverter as DC voltage (speed) and current (torque). Most small turbines use an AC alternator and a diode rectifier bridge to convert variable frequency AC from the alternator to DC power.
The inverter uses a programmed power versus voltage curve to command current from the turbine dependent upon the DC voltage generated by the turbine. Each alternator design has an optimum operating point or power curve of speed (voltage) versus torque (current). The Windy Boy incorporates a linear power curve that may be programmed by the user to match the characteristics of the specific wind turbine alternator."
So yeah, it looks like you do use a bridge rectifier and feed the Windy Boy from your AC wind generator. The input requirements on page 3 and 4 also say:
"Maximum DC Ripple 5% peak-to-peak"
So I would think that means some smoothing capacitor(s) are required, as well.
Also to consider -- I have no idea what DC voltage your windmill can/will produce. But the Windy Boy specs a max DC input:
"Maximum Input Voltage 400Vdc" for the WB1800U model
"Maximum Input Voltage 600Vdc" for the WB2500U model
My experience is that if you go above that, the Sunny Boy (for PV) inverters will shut off -- that may leave your windmill with no load (free spinning?). I know that I do not know about that, but I would think that may be a reasonable condition to caution against.
They also say:
"DC Over-voltage Protection
The largest danger to the inverter is from DC over-voltage. This is the common result of a wind turbine over-speed condition. The most radical over-voltage condition occurs when the inverter is processing power from the turbine and an event (most commonly a utility line fault) occurs causing the inverter to immediately stop processing power. When this happens, the power that was going to the utility is transferred back into the turbine as speed. The wind turbine will quickly increase speed, which causes the DC voltage to also increase rapidly. This can produce voltage in excess of 2000Vdc, if the turbine was fully loaded at the time of an event. Exceeding the maximum input voltage will void the inverter warranty.
Most turbine manufacturers have designed a protection circuit to protect power
processing equipment from this condition."
So you may want to have some system monitoring on the windmill portion that drops out a relay for over-voltage? And shifts it over to a dump-load? Dunno.
But they clearly do not want your problems to be their problem -- I guess they are not joking with the Warnings:
"Product Limitations and Warnings
The Windy Boy inverter is a standard inverter designed to be installed only with qualified wind turbines. Input protection is the responsibility of the turbine manufacturer or system integrator/installer. Misapplication of the Windy Boy may cause irreparable damage to the inverter and turbine system, and will void all product warranties. Please contact your turbine manufacturer for detailed system information.
The Windy Boy inverter is designed to operate with wind turbines employing a 3-phase generator and rectifier that produce current and voltage within the allowable operating ranges of the inverter. All protective wind turbine input functions (over-current, overvoltage, over-power, fault tolerance and recovery, turbine mechanical protection, etc.) are the responsibility of the turbine manufacturer or system integrator/installer."