SLIP FREQUENCY CALCULATOR OF INDUCTION MOTOR AND ROTATION CONTROLLER OF INDUCTION MOTOR USING THE SAME

摘要

PURPOSE:To accurately control the rotating speed of an induction motor without speed detector by detecting an input current to the motor and thereby leading the slip frequency. CONSTITUTION:An effective current calculator 8 inputs the input voltage V1 of an induction motor, a DC circuit voltage VDC, a DC circuit current IDC, a current command I, and an operating frequency f1, and obtains the secondary voltage (e), the secondary magnetic flux PHI2 and the secondary current I2'. A slip frequency calculator calculates a slip frequency fs from the secondary resistance value R2 from the secondary resistance value corrector 10, the magnetic flux PHI2 and the secondary current I2'. When the frequency fs is applied to the frequency command f*, the primary delay element 11 is provided and corrected to obtain the safety of control.