| 摘要 |
PURPOSE:To alleviate the duty of an element at the starting time by simultaneously firing an auxiliary thyristor and a main thyristor of opposed arms when the voltage of an input filter capacitor becomes the prescribed value when an inverter is started. CONSTITUTION:When a switch 22 is closed, a current is flowed in a circuit of a DC power source 13, the switch 22, a starting resistor 24, a reactor 25, and a capacitor 26, and the capacitor 26 is charged to the power source voltage without vibrating the voltage across the capacitor. A switch 23 is closed after the charging of the capacitor 26 is completed, thereby shortcircuiting the resistor 24. The voltage across the terminals of the capacitor 26 detected by a voltage detector 7 is compared with a set level by a voltage setter 30 in a comparator 28. When it becomes the set voltage or higher, the comparator 28 outputs a detection signal, and a firing signal is applied to a thyristor through a gate pulse generator 29. |
