| 摘要 |
PURPOSE:To reduce the current ripple of a DC motor at a low speed time by increasing the frequency of a triangular wave generator when the motor is rotated at a low speed and decreasing it when the motor is rotated at a high speed. CONSTITUTION:A speed controller 1 outputs as a current command signal B a deviation between a speed command A and a motor speed signal G, and a current control circuit 2 outputs as a motor terminal voltage command signal C a deviation between the current command signal B and the motor current signal F. A PWM signal generator 4 compares a motor terminal voltage command signal C with a triangular wave signal EE and applies a pulse width signal D to a power converter 5. A frequency controller 90 outputs a frequency command signal I which decreases the frequency of the triangular wave generator 30 when the motor 6 is rotated at a high speed time and increases it when the motor 6 is rotated at a low speed time. In this manner, the torque pulsation to be generated when the motor rotates at the low speed can be prevented. |
