POWER CONVERSION DEVICE FOR POWER STEERING OF ELECTRIC FORKLIFT TRUCK, AND ELECTRIC FORKLIFT TRUCK EMPLOYING THE SAME

摘要

PROBLEM TO BE SOLVED: To suppress an overcurrent that flows to a DC motor for power steering.SOLUTION: A power conversion device 300 is mounted on an electric forklift truck and drives a steering motor M3 on the basis of a control command value S3 indicating a rotation angle of a steering wheel of the electric forklift truck. A voltage command value generation part 304 generates a voltage command value S5 instructing a drive voltage to be applied to the steering motor M3 in accordance with the control command value S3. A limiter 306 (i) limits an increase speed of the voltage command value S5 and (ii) limits the voltage command value S5 to a predetermined first threshold value or less. A pulse modulator 308 generates a drive pulse S4 having a duty ratio corresponding to a voltage command value S6 via the limiter 306. A driver 310 drives a chopper switch 302 on the basis of the drive pulse S4.