It will be understood that electrical power generators and transformers are utilised in order to convert electrical power in terms of electrical voltage or current as well as with respect to power generation. One example of a transformer is of the rotating transformer type described in U.S. Pat. No. 3,611,230. Such rotating transformers act to couple electrical energy between a stator and a rotor member without physical contact between the moving rotating members. In such circumstances, a means for transferring electrical current in the generator between the rotating and stationary frames is provided without use of electrical brush gear. It will also be understood with respect to transformers utilised for wind generation that it is also known to use fixed cable connections with flexible cables and control systems that limit the wind up of the cables as a result of rotation of the turbine into the wind or marine current.
There is increasing desire to utilise renewable forms of energy for electrical power generation. Unfortunately previous rotating transformer designs were not typically specified for wind power generation and in particular operation at the level of electrical power generated, which is normally at least several hundred kilowatts. In such circumstances, prior arrangements have typically depended upon electrical brushgear which in turn requires considerable maintenance and care with respect to the atmosphere about the brushes in terms of humidity for correct operation of the brushes. In addition, fixed or flexible cable connections may not be utilised in certain unconventional wind turbine designs. With regard to a conventional horizontal axis wind power turbine, vanes can be used to orientate the turbine into the wind, without the complexity of currently used drive motors, control logic and sensors, provided the transformer will transform the power from the rotating frame of the turbine to the stationary frame.
It will be appreciated that brushless transfer is important with regard to power generation. Typically, electrical power will be generated by relative movement of a winding relative to an array of alternately polarised (i.e. north, south, north, south, etc.) permanent magnets in order to induce an alternating electric current. With an electrical generator, mechanical action to cause rotation is provided by a wind turbine or other power source.