Abstract: An uninterruptible power supply apparatus includes a cooler cooling a converter/chopper circuit and a cooler cooling a PWM inverter. The converter/chopper circuit and the cooler make up one integrated unit. Accordingly, a smaller apparatus can be achieved, compared with a conventional apparatus in which a cooler is provided for each of a converter and a chopper.

Abstract: An uninterruptible power supply apparatus includes a cooler cooling a converter/chopper circuit and a cooler cooling a PWM inverter. The converter/chopper circuit and the cooler make up one integrated unit. Accordingly, a smaller apparatus can be achieved, compared with a conventional apparatus in which a cooler is provided for each of a converter and a chopper.

Abstract: An uninterruptible power supply apparatus includes a cooler cooling a converter/chopper circuit and a cooler cooling a PWM inverter. The converter/chopper circuit and the cooler make up one integrated unit. Accordingly, a smaller apparatus can be achieved, compared with a conventional apparatus in which a cooler is provided for each of a converter and a chopper.

Abstract: There is provided an inverter test apparatus for testing an inverter interconnected with an alternating-current power system, the apparatus including an alternating-current power output unit configured to output alternating-current power, and an alternating-current power controller configured to control the alternating-current power output from the alternating-current power output unit to simulate an alternating-current load of the inverter.

Abstract: A control unit of an uninterruptible power supply device includes a PWM circuit generating a plurality of PWM signals controlling a plurality of IGBT elements of a power conversion unit; a plurality of output terminals for supplying the plurality of PWM signals to the plurality of IGBTs; and a switching circuit arranging the plurality of PWM signals in order in accordance with the type of the uninterruptible power supply device and supplying the PWM signals to the plurality of output terminals. Accordingly, the control unit can be shared among a plurality of types of uninterruptible power supply devices.

Abstract: In this uninterruptible power supply apparatus, even after electric power supply to a load stops due to prolonged power failure time, the operation of an inverter is continued, a DC power supply voltage is generated based on an output of the inverter, and a control circuit is driven by the DC power supply voltage. Therefore, when electric power supply from a commercial AC power supply is resumed during the stop of electric power supply to the load, electric power supply to the load is automatically resumed by the control circuit.

Abstract: In an uninterruptible power supply system, control sections of three uninterruptible power supply units are connected to one another by communication cables to configure one integrated control unit. The integrated control unit brings three switches into conduction if a bias feeding mode is selected by one arbitrary operation section and brings three switches into conduction if an inverter feeding mode is selected. Therefore, there is no need to separately provide an operation section and a control section for operating and controlling all of the uninterruptible power supply units.

Abstract: A power conversion apparatus includes an inverter for converting DC power to AC power for supply to a load, a converter for converting AC power from an AC power supply to DC power for supply to the inverter, a DC voltage converter for converting a voltage value of power stored in a storage battery to supply DC power from the storage battery to the inverter when power supply from the AC power supply is faulty, and a filter including a reactor and a capacitor, for removing harmonics generated by the inverter. The inverter includes a three-level circuit which is a multi-level circuit.

Abstract: A power conversion system includes n (n being an integer of 2 or more) power conversion devices (P1 to P4) connected in parallel to a load (4); and a communication line (2) connected to the n power conversion devices (P1 to P4). Each of power conversion devices includes a communication circuit (10) which transmits a load current value detected by a current sensor (37) to each of other (n?1) power conversion devices through the communication line (2), and receives (n?1) load current values transmitted through the communication line (2) from other (n?1) power conversion devices; and an operation circuit (11) calculating a shared current and a cross current of the corresponding power conversion device based on the n load current values. Accordingly, a wiring line is prevented from becoming complicated even when the number of power conversion devices is increased.

Abstract: A power conversion apparatus includes a comparison circuit which compares a determination element related to a loss in the power converter with a switching reference value and outputs a determination instruction when a difference has occurred between them, a determination circuit which outputs a two-level operation switching instruction when the determination element is greater than or equal to the switching reference value, and a switching circuit which, when having received a two-level operation switching instruction, turns off the alternating-current switch and turns on the valve devices in the arm sequentially, thereby bringing the power converter into a two-level operation state.

Abstract: A power conversion device includes an inverter for converting DC power to AC power to supply the AC power to a load, a converter for converting AC power from an AC power supply to DC power to supply the DC power to the inverter, a DC voltage converter for converting a voltage value of power stored in a storage battery to supply DC power from the storage battery to the inverter when power supply by the AC power supply is abnormal, and a filter which includes a reactor and a capacitor and removes harmonics generated by the inverter. The inverter includes a three-level circuit constituted of an arm and an AC switch.

Abstract: In an uninterruptible power supply apparatus, a common mode current flowing from nodes (N1 to N3) to a line of a ground voltage (GND) through a stray capacitance (41) of a battery (40) is limited by a common mode reactor (34), and the low-level common mode current passing through the common mode reactor (34) is caused to flow to a virtual neutral line (NL) through a common mode capacitor (37). Therefore, the level of noise caused by the common mode current can be reduced.

Abstract: In a power conversion device, reactors in an AC input filter absorbing a voltage at a carrier frequency of a PWM converter and reactors in an AC output filter absorbing a voltage at a carrier frequency of a PWM inverter include one six-leg six-phase iron core reactor. Accordingly, the device can be reduced in size when compared with a case where the reactors are composed of two four-leg six-phase iron core reactors.

Abstract: A power conversion apparatus includes an inverter for converting DC power to AC power for supply to a load, a converter for converting AC power from an AC power supply to DC power for supply to the inverter, and a DC voltage converter for converting a voltage value of power stored in a storage battery and supplying DC power from the storage battery to the inverter when power supply by the AC power supply is abnormal. The converter includes a first three-level circuit which is a multi-level circuit. Similarly, the DC voltage converter includes a second three-level circuit. A control device controls the first and second multi-level circuits to suppress potential fluctuation at a neutral point between first and second capacitors.

Abstract: In this uninterruptible power supply apparatus, even after electric power supply to a load stops due to prolonged power failure time, the operation of an inverter is continued, a DC power supply voltage is generated based on an output of the inverter, and a control circuit is driven by the DC power supply voltage. Therefore, when electric power supply from a commercial AC power supply is resumed during the stop of electric power supply to the load, electric power supply to the load is automatically resumed by the control circuit.

Abstract: A power conversion system includes n (n being an integer of 2 or more) power conversion devices (P1 to P4) connected in parallel to a load (4); and a communication line (2) connected to the n power conversion devices (P1 to P4). Each of power conversion devices includes a communication circuit (10) which transmits a load current value detected by a current sensor (37) to each of other (n?1) power conversion devices through the communication line (2), and receives (n?1) load current values transmitted through the communication line (2) from other (n?1) power conversion devices; and an operation circuit (11) calculating a shared current and a cross current of the corresponding power conversion device based on the n load current values. Accordingly, a wiring line is prevented from becoming complicated even when the number of power conversion devices is increased.

Abstract: A control unit of an uninterruptible power supply device includes a PWM circuit generating a plurality of PWM signals controlling a plurality of IGBT elements of a power conversion unit 3; a plurality of output terminals for supplying the plurality of PWM signals to the plurality of IGBTs; and a switching circuit arranging the plurality of PWM signals in order in accordance with the type of the uninterruptible power supply device and supplying the PWM signals to the plurality of output terminals. Accordingly, the control unit can be shared among a plurality of types of uninterruptible power supply devices.

Abstract: A three-level PWM converter includes first to third fuses having one terminals connected to a DC positive bus, a DC negative bus and a DC neutral point bus, respectively, first and second IGBT elements connected between respective ones of the other terminals of the first and second fuses and an AC line, an AC switch connected between the AC line and the other terminal of the third fuse, first and second diodes connected in anti-parallel to the first and second IGBT elements respectively, a first capacitor connected between the other terminals of the first and third fuses, and a second capacitor connected between the other terminals of the second and third fuses.

Abstract: In an uninterruptible power supply system, control sections of three uninterruptible power supply units are connected to one another by communication cables to configure one integrated control unit. The integrated control unit brings three switches into conduction if a bias feeding mode is selected by one arbitrary operation section and brings three switches into conduction if an inverter feeding mode is selected. Therefore, there is no need to separately provide an operation section and a control section for operating and controlling all of the uninterruptible power supply units.

Abstract: An uninterruptible power supply apparatus includes a cooler cooling a converter/chopper circuit and a cooler cooling a PWM inverter. The converter/chopper circuit and the cooler make up one integrated unit. Accordingly, a smaller apparatus can be achieved, compared with a conventional apparatus in which a cooler is provided for each of a converter and a chopper.