| 摘要 |
PURPOSE:To improve the torque characteristics of a load motor by improving current application ratio through th on-off operation of a capacitor circuit and the change of commutation off time. CONSTITUTION:A capacitor circuit connected through a switch is provided between a thyristor bridge circuit, inverse bias circuit, chopper switching element, and the output terminal of the thyristor bridge circuit. The on-off operation of a capacitor circuit consisting of the capacitors 14a to 14c and the change of the commutation off time of the chopper switching elements 8 and 9 are automatically performed in accordance with the current command for controlling the thyristor bridge circuit. This prevents the deterioration of torque characteristics due to the degradation of current application ratio in the high speed region which is the defect of a lumped commutation type inverter. Since the capacitor circuit is automatically separated in the low speed region, the capacitor loss generated by the resonance current which is applied to both the motor winding and the capacitor circuit can be eliminated. |
