| 摘要 |
A slip frequency control method for induction motors, capable of achieving accurate control and excellent in control response. To effect determination of a slip frequency (fs) and an excitation magnetic flux frequency ( omega 0) by software processing to reduce a control error and a control delay caused if hardware elements are employed for the determination of these parameters, a vector control processor divides, in a speed control routine (101-104), the sum of a slip frequency, obtained by dividing the product of a secondary current command (I2) and a proportional constant (K2) by an excitation magnetic flux command ( PHI ), and a remainder ( alpha ') in the preceding routine by a routine executing frequency (CV), so as to derive a slip amount (A) and a remainder ( alpha ) in the present routine. In a current control routine (201 to 205) executed at intervals of a period shorter than that of the speed control routine, the processor divides the sum of the derived slip amount and the remainder ( beta ') in the preceding routine by the number (n) of execution of the current control, to thereby derive slip distribution data ( omega s) and a remainder ( beta ) in the present current control routine, and further adds data ( omega r) indicative of an actual motor speed to the derived slip distribution data, to thereby derive an excitation magnetic flux frequency ( omega 0).
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