| 摘要 |
PURPOSE:To prevent the commutation failure of a frequency converter by varying the commutation margin time of an inverter in response to an output or a reference signal of the output. CONSTITUTION:An adder 13 inputs a signal 9a of a commutation margin time setter 9 and a signal 11a of an output reference setter 11. The output signal 13a of the adder 13 is inputted to a comparator 8, and compared with a triangular wave 7a to become a signal for controlling the commutation margin time of an inverter. When the output of a frequency converter is increased or decreased by the setter 11, the commutation margin time of the inverter can be varied in response to the reference signal. |
