SLIP FREQUENCY CONTROL METHOD FOR INDUCTION MOTORS

摘要

In the speed control routines (101 to 104), a slip quantity (A) and a remainder (alpha) obtained by the running of the routine of this time are calculated by dividing by a routine start frequency (CV) the value obtained by addition of the remainder (alpha') calculated by the running of the routine of the preceding time and a slip frequency that is obtained by dividing the product of a secondary current instruction (12) and a proportional constant (K2) by the excitation flux instruction. In the current control routine (201 to 205) executed on a period shorter than that of the speed control routine, a slip distribution data (ws) and a remainder of this time (beta) are calculated by dividing the value obtained by addition of a slip quantity to be calculated and the remainder (beta') of the preceding time by the number (n) of times of starting the current control routine. Furthermore, data (wr) that represents an actual motor speed is added to the calculated strip distribution data in order to obtain an exciting flux frequency (w0).