| 摘要 |
PURPOSE:To change over the action signals of the inverter to pulses synchronizing with a commercial power source smoothly by a method wherein the combination of rectangular wave pulses is in the same frequency as to the commercial power source and pulses, whose rise time is delayed to the said pulses, and a logical circuit are combined. CONSTITUTION:A rectangular wave generating circuit 2 generates the rectangular waves in the same frequency as a commercial power source, and a delaying circuit 3 generates rectangular waves rising at a point of time later than the rectangular waves. When synchronous point detecting signals are not inputted to an AND circuit 6, signals with the same wave forms as the output signals of the delaying circuit 3 are inputted to a pulse distributor 8 for driving an inverter. When the synchronous point detecting signals are inputted to the AND circuit 6, a FF circuit 5 is not subject to an effect of the output of the rectangular wave circuit 2 after fall signals are emitted from a NOT circuit 4, and output from a logical circuit 7 is synchronized with the commercial power source. A logical mistake in case of the change-over of the logical circuit 7 is prevented by means of the delaying circuit 3. |
