| 摘要 |
PURPOSE:To suppress the frequency change rate by limiting a signal in response to the phase difference between an external power source voltage and an inverter output voltage to the prescribed time width within each zone divided in a plurality to input to a phase synchronizer system. CONSTITUTION:An inverter 1 of an external power source synchronous inverter supplies power through an AC switch 2 to a load 3, and a backup external power source 4 supplies power through an AC switch 5 to the load 3. The controller of the inverter 1 is composed of a gate controller 8 through a frequency divider 7 from a voltage control oscillator 6. In this case, to synchronize the voltage of the power source 4 with the output voltage of the inverter 1, a synchronization instructing circuit 9 and a phase comparator 10 are provided. Thus, the phase difference of the both is detected in response to a deviation of the both output voltages, and input only in the prescribed time width at the center of the zone of each half cycle. The prescribed time width is gradually expanded by the manner used for longitudinally increasing from the center. |
