Uninterruptible power supply and parallel operation type non-uninterruptible power supply and the inverter device and parallel operation type inverter device

摘要

PROBLEM TO BE SOLVED: To provide a parallel operation type uniterrupted power supply device which can prevent a load share of one uninterrupted power supply device from being significantly increased even if respective uninterrupted power supply devices are operated while operation states of other uninterrupted power supply devices are not watched.;SOLUTION: An uninterrupted power supply device 1a comprises an inverter circuit 3a and an inverter circuit controller 5a. The inverter circuit controller 5a includes a PWM control signal generating means 19a. The PWM control signal generating means 19a generates a PWM control signal which reduces gradually the output voltage of the inverter circuit 3a according to the increase of a supplied active power until a decidion means 17a decides that the supplied effective power reaches a prescribed value. After the decision means decides that the supplied active power reaches the prescribed value, the means reduces the output voltage with a reduction rate larger than before so as not to rush into an overload state.;COPYRIGHT: (C)2002,JPO