Development of Intelligent Wind Turbine Unit with Tandem Wind Rotors and Double Rotational Armatures (2nd Report, Characteristics of tandem wind rotors)

Abstract

The authors have invented the superior wind turbine unit which is composed of the tandem wind rotors and the double rotational armature type generator without the traditional stator. The large-sized front wind rotor and the small-sized rear wind rotor drive the inner and the outer armatures respectively, in keeping the rotational torque counter-balanced. Such operating conditions may be able to make the output higher than the traditional wind turbines, and to keep the output constant in the rated operation mode without the brakes and/or the pitch control mechanism. The unique rotational conditions of the tandem wind rotors and the fundamental characteristics of this unit were presented at the previous paper. Continuously, this paper discusses experimentally the effects of the tandem wind rotor profiles on the characteristics of this unit. The desirable profiles and the main results are as follows. (1)The optimum diameter ratio is DRF (rear wind rotor diameter divided by the front wind rotor diameter) = 0.84, and the axial distance between both wind rotors should be set as short as possible. (2)The output is higher while the relative tip speed ratio increases as compared with the single wind rotor.