| 摘要 |
PURPOSE:To prevent the overlapping of surge voltage in the case when armature and field choppers are at OFF by synchronizing time just before the armature chopper is at OFF and the time when the field chopper is at ON. CONSTITUTION:A microcomputer 1 inputs signals from an accelerator device 8, a brake gear 9, a main circuit 10, and a speed detecting circuit 19, computes the motor current command value which must be flowed to a motor 132 according to controlling characteristics previously memorized to a memory, compensation-computes current controlling and gives a flowing-rate control circuit 15 of an armature chopper and a field chopper a chopper period and a rate of flowing. The flowing- rate control circuit period and a rate of flowing. The flowing-rate control circuit 15 outputs signals for the field chopper just before signals for the armature chopper are at OFF. Thus, the overlapping of surge voltage in the case when the armature and field choppers are at OFF can be prevented, and an element having low dielectric resistance can be used as a chopper circuit. |
