| 摘要 |
A conversion device is provided with: a DC bus provided between a DC power supply and an AC electrical path and having a smoothing capacitor connected thereto; a first converter provided between the DC power supply and the DC bus and performing a DC/DC conversion; a second converter provided between the DC bus and the AC electrical path and performing a DC/AC or AC/DC conversion using switching elements connected in a full-bridge configuration; a voltage sensor for detecting the voltage between both ends of the capacitor as a DC bus voltage; and a control unit for selectively operating the first converter and the second converter within one AC cycle of the AC electrical path, thereby making a part of the absolute value of an AC waveform and a DC waveform appear alternately as the DC bus voltage. The control unit detects an arm short-circuit in the second converter on the basis of the degree of a DC bus voltage drop occurring during the operation of the second converter. |
