| 摘要 |
PURPOSE:To control the revolution speed of an induction motor without using a speed power generator by calculating the revolution speed of the induction motor on the basis of the voltage and electric current, by using a sensorless control circuit as speed controller. CONSTITUTION:The speed difference between the speed instruction omegan deg. and the speed calculation value omegan deg. is converted to a torque current instruction I1q deg. through a speed controller 62, and the difference from the torque current calculation value I1q deg. is calculated by a subtraction calculator 65, and a current difference is generated. The current difference is added with the slip angular speed omegas deg. by an adder 67, and inputted into a voltage control oscillator 68, and the magnetic angular speed omega is controlled so that the torque current calculation value I1q deg. accords with the torque current instruction I1q deg., and fitted with the slip frequency omegas deg. corresponding to the actual constant of an induction motor 13. Further, the primary current instruction value I1q deg. and torque current instruction I1q deg. are converted to the ac current instruction value il deg. through a vector calculator 72 and a vector revolution device 74, and the difference from the primary current i1 is calculated by a subtraction calculator 78, and inputted into an inverter circuit 20. |
