| 摘要 |
PURPOSE:To reduce the charging voltage vibration of a snubber capacitor by discharging a snubber energy through a resistor for the initial certain period, turning ON a semiconductor switch, and shortcircuiting the resistor. CONSTITUTION:An inverter with a self-arc-extinguishing type switching element 1 as an arm element is formed by connecting in series reactors 2 between th elements 2, in anti-parallel feedback diodes 3 and in parallel snubbers 4. A diode rectifier 7 is provided, and the discharging current of the capacitor 41 of the snubber 4 is returned through a current transformer 10 to a DC power source. In this case, the transformer 10 has a middle tap M, a resistor 9 is inserted as a damping element between the tap M and the anode side of a semiconductor switch 8, the firing circuit 11 of the switch 8 is provided, and when the voltage of the resistor 9 rises to the certain level after the feedback is started, the switch 9 is closed to shortcircuit the resistor 9. |
