| 摘要 |
PURPOSE:To control an efficiency of an induction motor to be driven by an inverter in an optimum range irrespective of a fluctuation in a load. CONSTITUTION:A magnitude of a present load torque is calculated by using an output voltage value V1 of an inverter for driving an induction motor IM, a current value I, a magnitude of a frequency f and a motor constant of the motor IM. An exciting current value C for imparting an optimum motor efficiency to the torque is calculated. A primary voltage V1 for realizing the exciting current is calculated, and the inverter is so controlled as to become the voltage V1. This is repeated to generate a torque corresponding to the load torque, and a load follow-up torque control for holding the efficiency of the motor in an optimum range is executed. |
