| 摘要 |
PURPOSE:To enable a highly accurate torque control of a motor simply by providing a frequency control system with a slip frequency according to a deviation of a torque pattern of said motor from a motor current. CONSTITUTION:A torque pattern TMP is computed from a power running/ regeneration command P/B, a notch command and a variable load. Also, a secondary current I2 is obtained from a motor current IM and an actual slip frequency f's, and a motor torque TM is computed from said secondary current I2 and actual slip frequency f's. Then, a torque deviation DELTATM is obtained by comparison between the torque pattern TMP and motor torque TM through a comparator 13, and a slip freuquency fs is obtained from said torque deviation DELTATM and power running, regeneration commands P, B. Further, the slip frequency fs and a motor rotational frequency fr are subjected to addition and subtraction to obtain an inverter output frequency command fI and a pulse mode command PM. On the other hand, a percentage modulation r is obtained according to a deviation DELTAIO of an exciting current IO from an exciting current command IOP computed from the motor current IM and actual slip frequency f's. |
