|This article is intended as a suggestion for manufactures of, and users of large wind turbines. Users have noted reliability problems mostly due to the use of a mechanical gear transmission required to transform the relatively slow rotational speed of the large turbine hub to the required shaft speed of the synchronous alternator.|
|Better Wind Turbine Transmission|
John G. Murphy, Dakota Earth, Wind & Sun Inc.
Users have noted reliability problems mostly due to the use of a mechanical gear transmission required to transform the relatively slow rotational speed of the large turbine hub to the required shaft speed of the synchronous alternator. Further, all of that machinery on top of the tower adds unnecessary weight and maintenance complexities. Also, the fixed gear transmission does a poor job of matching the highly variable output of the wind turbine to the required input of the 60 Hz alternator. Any potential energy below the “start-up” speed of the machine is not harvested. There is no buffer.
As diligent and resourceful as most wind turbine manufactures are, I am surprised that you all have not taken some cues from locomotive and large equipment engineers. They would never think of using a mechanical gear transmission in their equipment.
Here are some ideas:
A Wind turbine direct coupled with a D.C. Generator (rectified poly phase alternator) or Hydraulic pump, or Air Compressor.
At the base of the tower, a blocking diode or check valve for isolation between machines.
On the ground, An accumulator, A Governor, then D.C. motor, or Hydraulic motor, or Air motor direct coupled to a 3 phase, 60 Hz Alternator to feed the Power Grid
Of the three choices, the latter is preferred. That is;
A Wind turbine direct coupled with an Air Compressor. At the base of the tower, a check valve for isolation between machines. On the ground within the wind farm, an accumulator, a governor regulated air motor direct coupled to a 3 phase, 60 Hz Alternator to feed the Power Grid.
I have included a simple, albeit crude block diagram below of a much better basic premise for large wind turbines, especially when an array of them are used in a wind farm.
The material cost for this version is much lower. The transmission line between turbines and the motor-generator is steel pipe rather than copper cable or hydraulic hose. The Air Compressor provides potential energy to the accumulator even at lower wind speeds. The medium is air so a return loop is not essential, the medium is free and without spillage problems. The accumulator is simply a large air tank rather than an expensive troublesome bank of batteries. If properly sized, the steel pipe transmission line between the wind turbines and the nearby motor-generator extends the capacity of the accumulator tank rather than being a source of loss as is an electric cable.
This is a time in our world that we need to brainstorm for solutions rather than succumbing to greed. If you think my belief in that is valid and my ideas have merit, I ask that you respond.