Abstract: The semiconductor device according to the present invention includes a semiconductor module, a cooling member, and a heat transfer member. The semiconductor module includes a switching element and a diode connected in antiparallel to each other. The heat transfer member is disposed between the semiconductor module and the cooling member so as to transfer heat generated by the switching element and the diode to the cooling member. The heat transfer member has a mounting surface on which the switching element and the diode are mounted side by side and a surface which is opposite to the mounting surface and is disposed in contact with the cooling member. In the heat transfer member, the thermal conductivity in a first direction parallel to the mounting surface is higher than the thermal conductivity in a second direction perpendicular to the mounting surface.

Abstract: In an uninterruptible power supply apparatus, in a power failure of a commercial AC power supply, a switch is turned off to electrically cut off the commercial AC power supply from an AC input filter, and a DC voltage converter is controlled such that a DC voltage that is the difference between terminal-to-terminal voltages of first and second capacitors is eliminated, and when the DC voltage exceeds a threshold voltage, a converter is controlled to reduce the DC voltage.

Abstract: A controller (3) includes an AC voltage generator (12) that generates first to Nth AC voltages, a DC voltage generator (13) that converts the first to Nth AC voltages into first to Nth DC voltages, respectively, and a driver (14) that turns on and off a switch (1) based on the first to Nth DC voltages. The AC voltage generator (12) includes first to Nth isolation transformers (T1 to TN). The primary windings of the nth and (n+1)th isolation transformers receive an AC source voltage. The nth to first isolation transformers are sequentially connected. The (n+1)th to Nth isolation transformers are sequentially connected. The first to Nth isolation transformers respectively output the first to Nth AC voltages from their respective secondary windings.

Abstract: A controller (5) of an uninterruptible power supply apparatus includes: first to sixth comparator circuits (22a to 22f) respectively provided corresponding to first to sixth IGBTs (Q1 to Q6) and outputting, based on a comparison result of the magnitude of three-phase AC voltages, signals (A1 to A6) indicating that a corresponding IGBT is to be turned on; and a control unit (23) that, when a voltage between terminals (VD1 or VD2) of a first or second capacitor (C11 or C12) is higher than a target voltage (VDT), turns on and off each of the first to sixth IGBTs based on signals output from the first to sixth comparator circuits to decrease the voltage between terminals of the first or second capacitor.

Abstract: The uninterruptible power supply device includes a switch (2) that includes first to Nth IGBT units (U1 to UN) connected in series, and a controller that turns on the switch by turning on the first to Nth IGBT units, and turns off the switch by firstly turning off the first to nth IGBT units and then turning off the (n+1)th to Nth IGBT units. Compared with the case where the first to Nth IGBT units are turned off at the same time, it is possible to reduce a surge voltage generated between the terminals of the switch (2).

Abstract: A switch circuit includes n switching elements (n?2) connected in series between an input node and an output node. A control device is configured to convert DC power in a power storage device into AC power synchronized with AC power supplied from an AC power supply during a normal state and supply the AC power to the output node, by controlling a power converter, when an abnormality of at least one of the AC power supply and the switch circuit is sensed in a state where the control device outputs conduction commands for the n switching elements. The control device is further configured to produce cutoff commands for cutting off the n switching elements during execution of power conversion in the power converter, and sense a cutoff abnormality of the switch circuit based on terminal-to-terminal voltages of the n switching elements during production of the cutoff commands.

Abstract: A power conversion device includes a converter, a first capacitor, and a second capacitor. The first capacitor is connected between a DC positive bus and a DC neutral point bus. The second capacitor is connected between the DC neutral point bus and a DC negative bus. The converter includes a diode rectifier connected between an AC power supply and each of the DC positive bus and the DC negative bus, and a first AC switch electrically connected between the AC power supply and the DC neutral point bus. The power conversion device further includes a first fuse electrically connected between the first AC switch and a connection point between the first and second capacitors.

Abstract: A power supply system includes: a semiconductor switch (1) that is turned on at the time of normal supply from a commercial AC power supply (5); a first current detector (CT1) including a transformer (10) and configured to detect an AC input current (I1); a second current detector (CT2) including a Hall effect sensor (20) and configured to detect an AC output current (I2); and a failure detector (30) that determines that one of a pair of thyristors (1a, 1b) included in the semiconductor switch (1) has misfired when the detection values from the first and second current detectors (CT1, CT2) are not equal at the time of normal supply from the commercial AC power supply (5).

Abstract: An AC switch (1) includes a first thyristor (T1), a second thyristor (T2), a third thyristor (T3), and a fourth thyristor (T4). The first thyristor (T1) has an anode connected to an AC power source (2), and a cathode connected to a load (3). The second thyristor (T2) is connected in antiparallel to the first thyristor (T1). The third thyristor (T3) has an anode connected to the AC power source (2), and a cathode connected to the load (3). The fourth thyristor (T4) is connected in antiparallel to the third thyristor (T3). A current detector (5) detects the AC current supplied from the AC power source (2) to the load (3). A controller (6) causes the first thyristor (T1) and the third thyristor (T3) to conduct alternately and causes the second thyristor (T2) and the fourth thyristor (T4) to conduct alternately, for each one-cycle period of the AC current, in accordance with the detection value from the current detector (5).

Abstract: This uninterruptible power supply includes: a cooler (6) that dissipates heat of a converter (1) and an inverter (5); and a controller (8) that causes, when output power (Po) from the inverter (5) exceeds an upper limit value (PoH), reduces input power (Pi) to the converter (1) by power (?Po=Po?PoH) corresponding to a difference between them, and increases input power (Pb) to a bidirectional chopper (4) by power (2×PoH) that is twice as high as the power (?Po) corresponding to the difference.

Abstract: A controller (3) includes an AC voltage generator (12) that generates first to Nth AC voltages, a DC voltage generator (13) that converts the first to Nth AC voltages into first to Nth DC voltages, respectively, and a driver (14) that turns on and off a switch (1) based on the first to Nth DC voltages. The AC voltage generator (12) includes first to Nth isolation transformers (T1 to TN). The primary windings of the nth and (n+1)th isolation transformers receive an AC source voltage. The nth to first isolation transformers are sequentially connected. The (n+1)th to Nth isolation transformers are sequentially connected. The first to Nth isolation transformers respectively output the first to Nth AC voltages from their respective secondary windings.

Abstract: The uninterruptible power supply device includes a switch (2) that includes first to Nth IGBT units (U1 to UN) connected in series, and a controller that turns on the switch by turning on the first to Nth IGBT units, and turns off the switch by firstly turning off the first to nth IGBT units and then turning off the (n+1)th to Nth IGBT units. Compared with the case where the first to Nth IGBT units are turned off at the same time, it is possible to reduce a surge voltage generated between the terminals of the switch (2).

Abstract: In an uninterruptible power supply apparatus, in a power failure of a commercial AC power supply, a switch is turned off to electrically cut off the commercial AC power supply from an AC input filter, and a DC voltage converter is controlled such that a DC voltage that is the difference between terminal-to-terminal voltages of first and second capacitors is eliminated, and when the DC voltage exceeds a threshold voltage, a converter is controlled to reduce the DC voltage.

Abstract: The semiconductor device according to the present invention includes a semiconductor module, a cooling member, and a heat transfer member. The semiconductor module includes a switching element and a diode connected in antiparallel to each other. The heat transfer member is disposed between the semiconductor module and the cooling member so as to transfer heat generated by the switching element and the diode to the cooling member. The heat transfer member has a mounting surface on which the switching element and the diode are mounted side by side and a surface which is opposite to the mounting surface and is disposed in contact with the cooling member. In the heat transfer member, the thermal conductivity in a first direction parallel to the mounting surface is higher than the thermal conductivity in a second direction perpendicular to the mounting surface.

Abstract: This uninterruptible power supply includes: a cooler (6) that dissipates heat of a converter (1) and an inverter (5); and a controller (8) that causes, when output power (Po) from the inverter (5) exceeds an upper limit value (PoH), reduces input power (Pi) to the converter (1) by power (?Po=Po?PoH) corresponding to a difference between them, and increases input power (Pb) to a bidirectional chopper (4) by power (2×PoH) that is twice as high as the power (?Po) corresponding to the difference.

Abstract: A switch circuit includes n switching elements (n?2) connected in series between an input node and an output node. A control device is configured to convert DC power in a power storage device into AC power synchronized with AC power supplied from an AC power supply during a normal state and supply the AC power to the output node, by controlling a power converter, when an abnormality of at least one of the AC power supply and the switch circuit is sensed in a state where the control device outputs conduction commands for the n switching elements. The control device is further configured to produce cutoff commands for cutting off the n switching elements during execution of power conversion in the power converter, and sense a cutoff abnormality of the switch circuit based on terminal-to-terminal voltages of the n switching elements during production of the cutoff commands.

Abstract: A power supply system includes: a semiconductor switch (1) that is turned on at the time of normal supply from a commercial AC power supply (5); a first current detector (CT1) including a transformer (10) and configured to detect an AC input current (I1); a second current detector (CT2) including a Hall effect sensor (20) and configured to detect an AC output current (I2); and a failure detector (30) that determines that one of a pair of thyristors (1a, 1b) included in the semiconductor switch (1) has misfired when the detection values from the first and second current detectors (CT1, CT2) are not equal at the time of normal supply from the commercial AC power supply (5).

Abstract: A controller (5) of an uninterruptible power supply apparatus includes: first to sixth comparator circuits (22a to 22f) respectively provided corresponding to first to sixth IGBTs (Q1 to Q6) and outputting, based on a comparison result of the magnitude of three-phase AC voltages, signals (A1 to A6) indicating that a corresponding IGBT is to be turned on; and a control unit (23) that, when a voltage between terminals (VD1 or VD2) of a first or second capacitor (C11 or C12) is higher than a target voltage (VDT), turns on and off each of the first to sixth IGBTs based on signals output from the first to sixth comparator circuits to decrease the voltage between terminals of the first or second capacitor.

Abstract: First to third-phase converters convert first to third-phase AC voltages into DC voltages, respectively. First to third DC positive buses and first to third DC negative buses are electrically connected to the first to third-phase converters. Fourth to sixth-phase inverters convert the DC voltages into fourth to sixth-phase AC voltages. The first to third-phase converters include diode rectifiers. First to third fuses are connected between an AC power supply and the first to third-phase converters, respectively. Fourth to sixth fuses are inserted into the first to third DC positive buses, respectively. Seventh to ninth fuses are inserted into the first to third DC negative buses, respectively.

Abstract: A power conversion device includes a converter, a first capacitor, and a second capacitor. The first capacitor is connected between a DC positive bus and a DC neutral point bus. The second capacitor is connected between the DC neutral point bus and a DC negative bus. The converter includes a diode rectifier connected between an AC power supply and each of the DC positive bus and the DC negative bus, and a first AC switch electrically connected between the AC power supply and the DC neutral point bus. The power conversion device further includes a first fuse electrically connected between the first AC switch and a connection point between the first and second capacitors.