| 摘要 |
The invention relates to a protective circuit for an inverter having semiconductor control elements. The protective circuit includes a series regulator in its inlet branch and an intermediate filter circuit with the capacitor thereof extending between the inlet and outlet branches. First and second signal generators control the series regulator and the inverter. A control unit controls the first signal generator for normal operation. Parallel comparator units have monitoring inputs connected to different parts of the protective circuit for detecting abnormal conditions and outputs connected to both of the signal generators to effect the immediate turning off of the series regulator and the inverter when abnormal conditions are sensed. The inverter is off concurrently with the comparator output signal but a multivibrator switch having a predetermined period causes the series regulator to be off during that whole period independently of the comparator output signal. With the series regulator off and the inverter turned on, the filter capacitor is allowed to discharge through the inverter. If the abnormal condition does not disappear during this operational sequence, the sequence is repeated. |
