A technology called torque vectoring – commonly used to improve handling in cars by varying the drive torque between wheels – is being offered as a way to make wind turbines operate more efficiently.
At the root of this development is an inherent fact of wind and wind turbines: They aren’t consistent. Wind speeds vary, which, quite obviously, leads to turbines turning at variable speeds. This is an issue because power needs to enter the grid at a set, consistent frequency (usually 60 hertz in the United States). So to make wind power work, the variable alternating current power it generates has to be run through a rectifier, turning it into direct current, and then converted back to AC at the target frequency. In the process, around 5 percent of the power generated by the turbine is lost.
According to Science Daily, researchers at Technische Universitaet Muenchen (TUM) figured out a way to accomplish a steady 50 Hertz (the typical European grid frequency) by developing “a novel active torque-vectoring gear analogous to a controlled differential in motor vehicles.”
They pulled this off by combining the planetary gears that generate most of the power in conventional designs with a torque-vectoring gear with a supplemental electric motor that can be used as both as a drive and as a generator. “This allows the power from the rotor to be either be boosted or diverted, leading to a constant rotational speed of the generator.”
Science daily says “the advantage of this concept is a lighter power train that requires a much smaller nacelle for the wind turbine. Additionally a robust, low-maintenance synchronous generator can be used, which dispenses with the need for power electronics for frequency adjustment, thereby increasing the overall facility efficiency.”