| 摘要 |
<P>PROBLEM TO BE SOLVED: To reduce the repeating frequency of charging/discharging of an electrolytic capacitor and realize the long life and small capacity thereof even when this is used in a country or region where voltage fluctuation of a commercial AC power supply is large. <P>SOLUTION: When an input AC voltage is within a range less than 90% and equal to or more than 70% of a rating input voltage, a DC-AC conversion operation is performed by an auxiliary inverter 30 while keeping the switch of a selection part 13 in an on-state, and a compensation power based on an input AC power is generated and added to the input AC power via an injection transformer 32. Thereby, a load 2 can be operated without time limit at an AC voltage of 90% of the rating input voltage without using the storage power of an electrolytic capacitor 17. If the input AC power drops to lower than 70% of the rating input voltage, the switch of the selection part 13 is turned off to perform a DC-AC conversion operation by a main inverter 18 and the load 2 is operated by an alternative AC power obtained by converting a DC power stored in the electrolytic capacitor 17. <P>COPYRIGHT: (C)2012,JPO&INPIT |
