In a fluid power generator system using operative fluid energy, a measured
tip speed ratio and a reference tip speed ratio are compared with each
other. If the measured tip speed ratio is smaller than the reference tip
speed ratio, a generator is placed in a no-load state, thereby restoring
the number of rotations of the wing axial shaft to the number of rotations
corresponding to the reference tip speed ratio. Further, the operation of
the generator is controlled on the basis of the tip speed ratio calculated
from the flow rate of the fluid, thereby providing a maximum output for
each flow rate. In this way, a change in the flow rate and number of
rotations can be appropriately dealt with and the maximum output for each
flow rate of the operative fluid can be dealt with, thereby increasing a
quantity of generated power.
