Abstract: In the present uninterruptible power supply apparatus, in a switching period in which a bypass power feed mode is switched to an inverter power feed mode, a semiconductor switch is turned on, a first electromagnetic contactor is turned off, a second electromagnetic contactor is turned on and, in this state, an inverter is activated to start a lap power feed mode, and the semiconductor switch is turned off to end the lap power feed mode. Accordingly, the lap power feed mode can be completed in a short time to reduce an increase of a terminal-to-terminal voltage of a capacitor and thereby prevent the terminal-to-terminal voltage of the capacitor from exceeding an upper limit voltage.

Abstract: In an uninterruptible power supply apparatus, AC current, which includes a feedback component having a value corresponding to deviation between terminal-to-terminal voltage of a capacitor and reference voltage, and a feed forward component obtained by multiplying load current by a gain, is passed into a converter such that the terminal-to-terminal voltage of the capacitor becomes the reference voltage. The gain is set to a first gain in an inverter power feed mode and a bypass power feed mode, and the gain is set to a second gain smaller than the first gain in a switching period of switching between the inverter power feed mode and the bypass power feed mode, to prevent the terminal-to-terminal voltage of the capacitor from exceeding an upper limit voltage in a lap power feed mode.

Abstract: A main controller includes a first programmable device, a device, and a first selector. Each controller includes a second programmable device and a second selector. The second programmable device includes a memory and a processor. The first selector connects the first programmable device to a serial communications line when the uninterruptible power supply is in operation. In response to the device receiving an instruction to perform an update process, the first selector connects the device to the serial communications line. The second selector connects the processor to the serial communications line when the uninterruptible power supply is in operation. In response to the processor receiving the instruction to perform the update process from the first programmable device while the uninterruptible power supply is in operation, the second selector connects the memory to the serial communications line.

Abstract: A voltage controller generates an AC current command value by adding a feed-forward term to a result of a control calculation performed for reducing a difference of a detected value of an AC voltage with respect to an AC voltage command value, the feed-forward term being determined by multiplying, by a gain, a detected value of primary winding current of a transformer. A current controller generates an inverter control command value by a control calculation performed for reducing a difference of a detected value of output current of the inverter with respect to the AC current command value. A PWM circuit generates a control signal for the inverter by comparing the inverter control command value with a predetermined carrier wave. When exciting inrush current is detected in a detected value of the primary winding current, the voltage controller sets the gain smaller than the gain when the exciting inrush current is not detected.

Abstract: An AC switch that includes a semiconductor switch and a snubber circuit connected in parallel between a first terminal connected to an AC power supply via a circuit breaker and a second terminal connected to a load. The power converter is connected between a power storage device and the second terminal. The current detector detects a current flowing through the AC switch. When the AC power supply is normal, the controller turns on the semiconductor switch. When an open state of the circuit breaker is detected, the controller controls the power converter to supply a current having a phase opposite to that of the current detected by the current detector to flow through the semiconductor switch and supply the AC power to the load. The controller further turns off the semiconductor switch in response to that the amplitude of the current detected by the current detector is 0.

Abstract: In this power conversion device, first three-phase AC voltages generated by an inverter and an AC filter are divided by first to third voltage dividers to generate second three-phase AC voltages, and third three-phase AC voltages that are line-to-line voltages of the second three-phase AC voltages and a neutral point voltage of the first three-phase AC voltages are detected. Then, DC components of the third three-phase AC voltages resulting from errors of voltage ratios of the first to third voltage dividers are obtained based on the detection results and contents in a storage unit, the DC components are removed from the third three-phase AC voltages to generate fourth three-phase AC voltages, and the inverter is controlled such that DC components of the fourth three-phase AC voltages are eliminated.

Abstract: In an uninterruptible power supply apparatus, AC current, which includes a feedback component having a value corresponding to deviation between terminal-to-terminal voltage of a capacitor and reference voltage, and a feed forward component obtained by multiplying load current by a gain, is passed into a converter such that the terminal-to-terminal voltage of the capacitor becomes the reference voltage. The gain is set to a first gain in an iverter power feed mode and a bypass power feed mode, and the gain is set to a second gain smaller than the first gain in a switching period of switching between the inverter power feed mode and the bypass power feed mode, to prevent the terminal-to-terminal voltage of the capacitor from exceeding an upper limit voltage in a lap power feed mode.

Abstract: An uninterruptible power supply apparatus having a plurality of power conversion modules and a bypass module connected in parallel between an AC power supply and a load. Each of the power conversion modules includes a first terminal that receives AC power from the AC power supply, a second terminal connected to a power storage device, a third terminal for outputting AC power to the load, a converter, an inverter, and a first control circuit. The bypass module includes a switch connected between the AC power supply and the load, a first voltage detector that detects an AC voltage applied to the first terminal, a second voltage detector that detects a DC voltage applied to the second terminal, a third voltage detector that detects an AC voltage applied to the third terminal, and a second control circuit.

Abstract: An uninterruptible power supply includes a plurality of vacuum circuit breakers and a bypass circuit connected in series between a commercial AC power supply and a load, a control device that turns on both of the plurality of vacuum circuit breakers and the bypass circuit when the commercial AC power supply is normal and turns off a vacuum circuit breaker different from a vacuum circuit breaker turned off on the occurrence of previous power failure of the plurality of vacuum circuit breakers and turns off the bypass circuit when the commercial AC power supply fails, and a power converter that converts DC power of a battery into AC power and supplies AC power to the load when the commercial AC power supply fails.

Abstract: In this power conversion device, first three-phase AC voltages generated by an inverter and an AC filter are divided by first to third voltage dividers to generate second three-phase AC voltages, and third three-phase AC voltages that are line-to-line voltages of the second three-phase AC voltages and a neutral point voltage of the first three-phase AC voltages are detected. Then, DC components of the third three-phase AC voltages resulting from errors of voltage ratios of the first to third voltage dividers are obtained based on the detection results and contents in a storage unit, the DC components are removed from the third three-phase AC voltages to generate fourth three-phase AC voltages, and the inverter is controlled such that DC components of the fourth three-phase AC voltages are eliminated.

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: In this uninterruptible power supply apparatus, respective phase differences between first to third carrier wave signals (CS1 to CS3) for a converter (1) and fourth to sixth carrier wave signals (CS4 to CS6) for an inverter (2) are set to 180 degrees in an inverter power feed mode and a bypass power feed mode, and respective phase differences between the first to third carrier wave signals and the fourth to sixth carrier wave signals are set to 0 degree in an overlap power feed mode. Zero-phase current (I01, I02) and circulating current (ICL) therefore can be reduced.

Abstract: A synchronization control circuit transforms a three-phase AC voltage supplied from a commercial AC power supply to a vector on rotational coordinates and calculates a first phase difference between the vector and a d axis. When magnitude of the first phase difference is larger than a prescribed value, the synchronization control circuit sets the first phase difference as it is as a second phase difference. When magnitude of the first phase difference is smaller than the prescribed value, the synchronization control circuit generates the second phase difference in reverse polarity to the first phase difference, and controls a frequency of a clock signal so as to set the second phase difference to 0 degree.

Abstract: A voltage controller generates an AC current command value by adding a feed-forward term to a result of a control calculation performed for reducing a difference of a detected value of an AC voltage with respect to an AC voltage command value, the feed-forward term being determined by multiplying, by a gain, a detected value of primary winding current of a transformer. A current controller generates an inverter control command value by a control calculation performed for reducing a difference of a detected value of output current of the inverter with respect to the AC current command value. A PWM circuit generates a control signal for the inverter by comparing the inverter control command value with a predetermined carrier wave. When exciting inrush current is detected in a detected value of the primary winding current, the voltage controller sets the gain smaller than the gain when the exciting inrush current is not detected.

Abstract: In the present uninterruptible power supply apparatus (U1), in a power failure of a commercial AC power supply (41), a switch (1) is turned off to electrically cut off the commercial AC power supply (41) from an AC input filter (2), and when DC voltage (?E=Ep?En) that is the difference between terminal-to-terminal voltages (Ep, En) of first and second capacitors (C1, C2) exceeds a threshold voltage (ETH), first and second IGBT devices (Q1, Q2) or third and fourth IGBT devices (Q3, Q4) included in the converter (3) are turned on and off to reduce DC voltage (?E).

Abstract: A synchronization control circuit transforms a three-phase AC voltage supplied from a commercial AC power supply to a vector on rotational coordinates and calculates a first phase difference between the vector and a d axis. When magnitude of the first phase difference is larger than a prescribed value, the synchronization control circuit sets the first phase difference as it is as a second phase difference. When magnitude of the first phase difference is smaller than the prescribed value, the synchronization control circuit generates the second phase difference in reverse polarity to the first phase difference, and controls a frequency of a clock signal so as to set the second phase difference to 0 degree.

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: In the present uninterruptible power supply apparatus (U1), in a power failure of a commercial AC power supply (41), a switch (1) is turned off to electrically cut off the commercial AC power supply (41) from an AC input filter (2), and when DC voltage (?E=Ep?En) that is the difference between terminal-to-terminal voltages (Ep, En) of first and second capacitors (C1, C2) exceeds a threshold voltage (ETH), first and second IGBT devices (Q1, Q2) or third and fourth IGBT devices (Q3, Q4) included in the converter (3) are turned on and off to reduce DC voltage (?E).

Abstract: In this uninterruptible power supply apparatus, respective phase differences between first to third carrier wave signals (CS1 to CS3) for a converter (1) and fourth to sixth carrier wave signals (CS4 to CS6) for an inverter (2) are set to 180 degrees in an inverter power feed mode and a bypass power feed mode, and respective phase differences between the first to third carrier wave signals and the fourth to sixth carrier wave signals are set to 0 degree in an overlap power feed mode. Zero-phase current (I01, I02) and circulating current (ICL) therefore can be reduced.

Abstract: An apparatus, applied to a vehicle having an internal combustion engine and an electric motor as power sources, comprises a changeover mechanism which is able to change a connection state of an electric motor output shaft to any one of “an IN-Connection State” in which a power transmission path is provided between a transmission input shaft and the electric motor output shaft, “an OUT-Connection State” in which a power transmission path is provided between the transmission output shaft and the electric motor output shaft, and “a neutral state” in which no transmission path therebetween is provided. When a changeover condition is satisfied, a period is provided in which a sum Ts of an internal-combustion-engine-side-output-torque Te and an electric-motor-side-output-torque Tm coincides with a required driving torque Tr, and an electric motor torque continues to be zero.