Abstract: An uninterruptible power source includes an eco-mode for supplying power from an AC power source to a load via a contactor. In the eco-mode, when a degree of voltage drop of the AC power source reaches 5%, a switching controller turns on a thyristor switch and then turns off a contactor. When the degree of voltage drop of the AC power source reaches 10%, a power conversion controller is configured to cause an inverter to invert DC power of a battery into AC power, and control the inversion in the inverter to synchronize the AC voltage output from the inverter to the AC voltage supplied from the AC power source. When the inversion in the inverter is performed after turning off contactor, the switching controller is configured to turn off the thyristor switch.

Abstract: An uninterruptible power supply system, including: a plurality of uninterruptible power supply devices which are connected in parallel with respect to a load, and switch between power supplies supplying power to the load depending on states of the power supplies; a control unit controlling an operation of switching between the power supplies by the uninterruptible power supply devices; and a storage battery connected to the plurality of uninterruptible power supply devices in common. The uninterruptible power supply device has a converter converting AC power of an AC power supply into DC power, a contactor switching between the DC power converted by the converter and DC power input from the storage battery, and an inverter inverting the DC power into AC power and supplying the power to the load. The control unit deactivates the converter which does not contribute to supplying a power amount required for the load, of a plurality of converters.

Abstract: Provided is an uninterruptible power supply apparatus that can properly adjust the capacity of cooling a heat radiation source. A housing for housing an uninterruptible power module is provided with a cooling fan for cooling the internal space of the housing. The housing is further formed with an opening. The opening formed in one housing and the opening formed in an adjacent housing for housing another uninterruptible power module are configured to face each other. Furthermore, each uninterruptible power module includes a fan control circuit for controlling the cooling fan. The fan control circuit controls the actuation and suspension of the cooling fan on the basis of a total load of the plurality of uninterruptible power modules.

Abstract: An uninterruptible power supply system, including: a plurality of uninterruptible power supply devices which are connected in parallel with respect to a load, and switch between power supplies supplying power to the load depending on states of the power supplies; a control unit controlling an operation of switching between the power supplies by the uninterruptible power supply devices; a storage battery connected to the plurality of uninterruptible power supply devices in common; a converter converting AC power; a contactor switching between the DC power converted by the converter and DC power input from the storage battery; and an inverter inverting the DC power and supplying the power to the load. The control unit deactivates the inverter which does not contribute to supplying a power amount required for the load, of a plurality of inverters.

Abstract: An uninterruptible power supply system, including: a plurality of uninterruptible power supply devices which are connected in parallel with respect to a load, and switch between power supplies supplying power to the load depending on states of the power supplies; a control unit controlling an operation of switching between the power supplies by the uninterruptible power supply devices; and a storage battery connected to the plurality of uninterruptible power supply devices in common. The uninterruptible power supply device has a converter converting AC power of an AC power supply into DC power, a contactor switching between the DC power converted by the converter and DC power input from the storage battery, and an inverter inverting the DC power into AC power and supplying the power to the load. The control unit deactivates the converter which does not contribute to supplying a power amount required for the load, of a plurality of converters.

Abstract: An inverter device capable of smoothly driving an alternating current synchronous motor of large capacity and high-speed rotation is provided. The inverter device includes a power rectification main circuit for converting alternating current power into direct current power and a PWM control inverse transformation main circuit. A transformer raises output terminal of the alternating current power of the inverse transformation main circuit to drive an alternating current synchronous motor. The alternating current motor is started bypassing the transformer and limiting output voltage of the inverse transformation main circuit to a low value through PWM control of the inverse transformation main circuit.

Abstract: An inverter device capable of smoothly driving an alternating current synchronous motor of large capacity and high-speed rotation is provided. The inverter device includes a power rectification main circuit for converting alternating current power into direct current power and a PWM control inverse transformation main circuit. A transformer raises output terminal of the alternating current power of the inverse transformation main circuit to drive an alternating current synchronous motor. The alternating current motor is started bypassing the transformer and limiting output voltage of the inverse transformation main circuit to a low value through PWM control of the inverse transformation main circuit.