| 摘要 |
PURPOSE:To alleviate the voltage duty of a semiconductor element by controlling the DC intermediate circuit voltage of the output side in response to the magnitude of a load, thereby suppressing the drop of the output voltage at load connecting/disconnecting time. CONSTITUTION:AC power supplied from a trolley wire 1 is led through a current collector into a vehicle, and transformed by a converter 2 to desired voltage. This is converted by a rectifier 3 to DC power, and an inverter 5 is connected through filters 6, 7 with the DC output side (DC intermediate circuit). The DC power is converted by the inverter 5 into the AC power of a constant voltage constant frequency, and supplied to a load 9. In this case, a DC current transformer 8 is provided in the intermediate circuit to detect the current I flowed to a smoothing reactor 6 by a current detector 10. This detection signal is set by a set voltage generator 11 to a high set voltage if the value of the current I is low, and to a low set voltage if high, and a deviation to the output of the detector 12 is calculated to drive the rectifier 3. |
