FAN CONTROL DEVICE

PROBLEM TO BE SOLVED: To provide a fan control device, for surely starting the fan even if the fan has already been rotated by an external force before start-up. SOLUTION: Resistors 14, 15, 16 detect winding current of an electric motor 4M for driving the fan, and a rotor speed estimation/calculation means 25 estimates the number of rotations of the electric motor based on voltage command value supplied to the electric motor and winding current. Calculation parts 29-34 calculate a torque component and an exciting component of the voltage command value so as to match the estimated rotation number of the electric motor and a preset target rotation number. When a waveform generation means 35 generates a driving waveform signal for driving a power conversion part 13, a rotation number detection command part 40 operates the power conversion part 13 before the start-up to make the rotor speed estimation/calculation means 25 estimate the rotation number of the electric motor, and start-up control means 21, 22 divide a predetermined low-speed range into a plurality of sections and set at least one of the target rotation number and the exciting component of the voltage command value to be a value unique to the start-up for each section so as to perform start-up control. COPYRIGHT: (C)2005,JPO&NCIPI