A maximum power point tracking method, applied to a tracking device,
employs a DC/DC converter connecting with a solar cell array, and
including a controller actuating the DC/DC converter to perform an active
resistance characteristic; a maximum power point tracking circuit
adjusting the active resistance of the DC/DC converter; monitoring a
change of an output power of the solar cell array in determining a
direction for adjusting the active resistance of the DC/DC converter; and
the maximum power point tracking circuit repeatedly adjusting the active
resistance of the DC/DC converter. If the change of the output power of
the solar cell array is positive, the active resistance of the DC/DC
converter is adjusted in the same direction; but, conversely, if the
change of the output power of the solar cell array is negative, the
active resistance of the DC/DC converter is adjusted in an opposite
direction.