How do you connect wind turbine driven asynchronous motors to the grid?

There are at least two basic ways to operate an induction generator connected to the utility power grid. One way is to closely regulate the generator speed so that it operates over a very narrow speed range between synchronous speed and something like 3% above synchronous speed. A continuously variable transmission could be used to convert the variable speed input shaft rotation driven by the wind turbine to a constant speed output shaft rotation to drive the generator. The pitch of the turbine blades could be continuously adjusted to maintain the generator speed within the required range. Another way is to allow the generator speed to vary over a wide range according to the wind while connected to a variable frequency motor controller that can both supply magnetizing current to the generator and accept power from the generator and convert the power to DC. Rather than store the power in batteries, capacitors are provided to filter the DC and provide the AC magnetizing current. All of the generated power is transferred immediately to the grid through a circuit that is similar to the input section. This is not an inverter of the type that is used to convert battery power to AC power. It is two inverters of a more complex design. Although the Clarion web site says that their product “can be plugged directly into the existing power grid without special wiring or expensive inverters” they also say it includes a “solid-state controller and a variable-speed induction generator.” I am reasonably certain that the controller is actually similar to the two-inverter circuit described above. The $400 price reflects the small size of the proposed system, not the simplicity of the controller. The web site says that the product can generate up to 40 kW-hrs per month. That is an average power of 55 watts. To accommodate a range of wind speeds, the system would need to be capable of generating a fair amount more than the average power. Since a 1/4 Hp (186 watt) variable frequency drive (VFD) and 3-phase motor can be purchased online for about $200, a $400 price for the Clarion system doesn’t seem unreasonable. Clarion apparently intends to have their product listed by Underwriters Laboratories as suitable for plug-in connection to the grid through an ordinary domestic power receptacle. It is not likely that anything like this can be done as a do-it-yourself project.

Connect it up with wire. Copper wire is best.

Asynchronous or induction generators are used with large scale wind generators, so that there is some slip, and there is less "jerking around" on the turbine/drive parts. References usually say they must have a gear-box, though I don't know why, other than they work at about 1% faster than the synchronous speed, and maybe even with lots of poles this is too fast for the rotors. Note that "The Jellyfish is still in the development phase as we work on additional design refinements and ensure that it is compliant with all applicable safety and regulatory requirements. We look forward to providing more details about our progress in the near future". Otherwise I found the site a bit strong on marketing hype, not much suggestion there that the wind may not blow enough to be meaningful, ever, but the money back return they quote on the $600 generator was 7 years. They also talk of enough power to light a house, not untrue, but it could be taken the wrong way. There is no doubt that an induction generator can sustain power and even self excite with a capacitor or two in the output. I think there are lines with enough capacitance, so "island power" (back-feeding when the grid is isolated) can conceivably result. Some electricity suppliers may be wary of a system that runs the meter backwards. Also in a grid connect system the metering is separate, so that different rates may be charged or paid for generated, exported and imported. I guess it is still bad practice to plug a generator into a wall outlet. Yes induction generators are supposed to only work when "excited" by the grid. The wiring of wall outlets is according to regulations. I doubt you could put more than the 20A for a 120V system into a wall outlet. I am not sure just where the current goes if you are generating 20A and taking a load of 15A on another outlet. I think you can expect that it is better as a three phase setup, rather than single phase. A single phase motor may work and from what I have seen of self excited induction generators on the internet could need capacitors for the second almost 90 degree phase, but the issue is that the supply people might not like them being connected. I can only guess what these guys are doing, but I think they have a multi-pole generator that works at lower RPM. The units in homes work at 1500 or 3000 synchronous speed for 50 Hz, 1800 or 3600 for 60Hz, so probably not suitable. When generating they would be a little higher in speed. I imagine the controller is an RPM sensor that connects them to the grid only when there is enough RPM, otherwise it runs as a motor and fan, until there is enough wind to "torque it up" above the synchronous speed.