| 摘要 |
This modular multilevel converter (110) is provided with arms (A1-A6) formed by the serial connection of one or a plurality of cells (10). A main circuit of each cell (10) includes a switching element and a direct current capacitor. A control circuit of each cell (10) transmits a voltage detection value from the direct current capacitor to a control device (120), and controls the switching on and off of the switching element in accordance with a control signal received from the control device (120). If the voltage detection value of at least one cell (10) exceeds a first threshold voltage, the control device (120) transmits a gate shut off signal to the control circuit of each cell (10). If the voltage detection value of a cell (10) exceeds a second threshold voltage higher than the first threshold voltage, the control circuit of said cell (10) autonomously sets the switching element of the main circuit thereof to the off state independently of a control signal, and short circuits the output terminal of the main circuit. |
