SECONDARY CURRENT FEEDBACK CONTROL SYSTEM OF INDUCTION MOTOR

摘要

PURPOSE:To keep torque at a command value even if secondary resistance varies with a temperature variation by detecting secondary current and making the difference between the command value and the detection value zero. CONSTITUTION:A current sensor 9 detects and measures secondary current of an induction motor 5 and outputs a detection value I2 to a subtracter 10. The subtracter 10 finds the difference I2 by subtracting a command value I2 of the secondary current from a detection value I2. An integrator 11 integrates an increment of frequency proportional to a difference I2 by time and finds a frequency increment f proportional to an integral value. An adding machine 12 adds the frequency increment f to power frequency f and inputs it as the power frequency into a unit rotary vector generator 7.