| 摘要 |
PURPOSE:To reduce the size and cost of a chopper circuit by applying a line voltage of AC input to a load when a chopper is in ON state, and applying a voltage between a neutral point of an AC input and an output terminal to the load when the chopper is in OFF state. CONSTITUTION:A 3-phase AC voltage from a 3-phase AC power source 1 is insulated and transformed by a transformer 2. The 3-phase voltage insulated and transformed by the transformer 2 is converted via a rectifier 3 made of diodes 3U-3Z into a DC voltage. A power source side capacitor 14 is connected between the positive electrode side of the DC output and the neutral point 2N of the secondary side of the transformer 2. The DC voltage outputted from the rectifier 3 is interrupted upon ON and OFF operations of a thyristor chopper 5, this interrupted DC voltage is smoothed by a DC reactor 6 and a smoothing condenser 8, and applied to a DC load 7. A freewheel diode 19 is connected to the polarity for preventing the voltage applied when the chopper 5 is ON between the load side of the chopper 5 and the neutral point 2N. |
