| 摘要 |
<p>A voltage controller has variable conductance (13), variable susceptance (14) set according to the excitation conductance and the excitation susceptance of an electric motor, and variable resistance (15) set according to the resistance of the primary and secondary windings of the electric motor. The voltage controller comprises means for calculating copper loss by processing a signal (e) proportional to the voltage of the fundamental wave supplied to the electric motor based on the variable conductance, and means for calculating core loss by processing the signal (e) proportional to the instantaneous voltage of the fundamental wave supplied to the electric motor and an instantaneous value (i) of the motor current based on the variable conductance, the variable susceptance, and the variable resistance. The copper loss and the core loss are compared, and the supply voltage to the electric motor is controlled so that the copper loss and the core loss may become equal. This achieves energy-saving operation of an electric motor.</p> |
