POWER CONVERSION SYSTEM AND UNINTERRUPTIBLE POWER SOURCE SYSTEM

摘要

Disclosed is an uninterruptible power source system provided with: a plurality of uninterruptible power source devices (U1 to U3) which are connected in parallel between a mains AC power source (70) and a load (71); and a control section (5) which selects the number of uninterruptible power source devices necessary for driving the load (71) from among the plurality of uninterruptible power source devices (U1 to U3), and which operates the selected uninterruptible power source devices while also stopping the remaining uninterruptible power source devices. The control section (5) changes, at a predetermined cycle, the operating uninterruptible power source devices in such a way that the operating times of the plurality of uninterruptible power source devices (U1 to U3) are mutually equal. The continuous operating times of the uninterruptible power source devices can therefore be reduced, making it possible to reduce the number of faults in the uninterruptible power source devices.