Intelligent wind power unit with tandem wind rotors - Wind Power Generation and Wind Turbine Design - page 333

CHAPTER 10

Intelligent wind power unit with tandem
wind rotors

Toshiaki Kanemoto 1 & Koichi Kubo 2
1 Faculty of Engineering, Kyushu Institute of Technology, Japan.
2 Graduate School of Engineering, Kyushu Institute of Technology, Japan.

Wind is clean, renewable and home grown energy source of the electric power gen-
eration, and has been positively/effectively utilized to cope with the warming global
environment. The propeller type wind turbines play main role in the wind power gen-
eration; however, it may have some weak points. To overcome the weak points of the
traditional one, the authors have investigated 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 rotational 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 pitch control mechanism. The
fi rst step toward practical use of this wind power unit, the characteristics of the double
rotational armature type synchronous generator and the double rotational armature
type doubly fed induction generator were investigated. Moreover, the desirable profi les
of tandem wind rotors such as optimum diameter ratio (rear rotor diameter divided by
front rotor diameter), blade numbers of both wind rotors and axial distance between
both wind rotors were also investigated. Furthermore, the fi eld tests of the wind turbine
unit had been carried out on the pick-up type truck driven straight at constant speed.

1 Introduction

The propeller type wind turbines play main role in the electric power generation.
The traditional propeller types may, however, have some weak points as follows:

1. The large-sized wind rotor generates the fruitful output but is not operated at

the weak wind, while the small-sized wind rotor can be operated at the weak
wind but the output is small.