| 摘要 |
PROBLEM TO BE SOLVED: To perform such operation as to operate a switching element safely even at sparking between collecting electrodes, and also, keep this operation mode regardless of the set value of the foundamental high voltage, in a pulse power unit for an electric dust collector. SOLUTION: As to the drive signal of a switching element for pulse generation, the operation is made, selecting such timing at off time that the spark does not occur, during the passage of recovery time after turning off of a switching element, corresponding to the mode of spark generation between dust collecting electrodes. As regards the spark generation mode, the current of a pulse circuit is detected, and when the current value in negative direction is larger than the specified value, the switching element is turned off at that period. Moreover, when the current value in negative direction is smaller than the specified value, the on drive is continued, and the switching element is turned off after two cycles of current oscillation. |
