Abstract: An uninterruptible power supply device includes: a converter that converts AC power supplied from an AC power supply into DC power and outputs the DC power to a first power supply node; a first bidirectional chopper that outputs DC power in a lead storage device to the first power supply node when the AC power supply has a power failure; a diode connected between the first power supply node and a second power supply node; a second bidirectional chopper that supplies and receives DC power between the second power supply node and a lithium ion battery; and a controller that controls the second bidirectional chopper to charge the lithium ion battery during regenerative operation of a load and to discharge the lithium ion battery during power running operation of the load.

Abstract: An uninterruptible power supply device includes a switch, a power converter, and another power converter. The switch includes a first electrode that receives AC power from an AC power supply and a second electrode connected to a load via an AC bus, and is turned on during a normal operation and turned off during a power failure. The power converter converts DC power from a DC power supply into AC power and outputs it to the AC bus during a power failure. The other power converter converts the AC power received from the AC bus into DC power and stores it in a lithium-ion battery when the load is performing regeneration running, and converts the DC power of the lithium-ion battery into AC power and supplies it to the AC bus when the load is performing power running.

Abstract: In an uninterruptible power supply apparatus, a bidirectional chopper (5) includes a first IGBT (Q1) for storing DC power generated by a converter (2) into a battery (22) and a second IGBT (Q2) for supplying DC power of the battery to an inverter (8). A control circuit (7) drives the first IGBT at a first frequency (fH) in a sound state of a commercial AC power supply (21) and drives the second IGBT at a second frequency (fL) lower than the first frequency in response to occurrence of a power failure of the commercial AC power supply. Switching loss produced in the second IGBT thus can be reduced.

Abstract: In an uninterruptible power supply apparatus, a bidirectional chopper (5) includes a first IGBT (Q1) for storing DC power generated by a converter (2) into a battery (22) and a second IGBT (Q2) for supplying DC power of the battery to an inverter (8). A control circuit (7) drives the first IGBT at a first frequency (fH) in a sound state of a commercial AC power supply (21) and drives the second IGBT at a second frequency (fL) lower than the first frequency in response to occurrence of a power failure of the commercial AC power supply. Switching loss produced in the second IGBT thus can be reduced.

Abstract: In an uninterruptible power supply device for supplying DC power to a load, a control device is configured such that, when the load is performing power running operation, the control device turns on a second switch to supply DC power from a diode rectifier to the load, turns off a first switch, and controls a converter to suppress a harmonic current contained in an AC current flowing from an AC power supply to the diode rectifier, and when the load is performing regenerative operation, the control device turns off the second switch, turns on the first switch, and controls the converter to convert regenerative power generated by the load into AC power.

Abstract: When a load current is larger than a predetermined value, a control device of an uninterruptible power supply device controls an inverter by gate signals having a relatively high frequency and having controlled pulse widths, and when the load current is smaller than the predetermined value, the control device controls the inverter by the gate signals having a relatively low frequency and having fixed pulse widths. Therefore, when a load is a light load, switching losses occurring in IGBTs of the inverter can be decreased.

Abstract: An uninterruptible power supply device includes: a converter that converts AC power supplied from an AC power supply into DC power and outputs the DC power to a first power supply node; a first bidirectional chopper that outputs DC power in a lead storage device to the first power supply node when the AC power supply has a power failure; a diode connected between the first power supply node and a second power supply node; a second bidirectional chopper that supplies and receives DC power between the second power supply node and a lithium ion battery; and a controller that controls the second bidirectional chopper to charge the lithium ion battery during regenerative operation of a load and to discharge the lithium ion battery during power running operation of the load.

Abstract: A generation circuit is configured to generate an output voltage command value Vor* for an inverter based on a three-phase reference value Vr, a zero-phase reference value, a detected value of a current sensor, and a detected value of a voltage sensor. A compensation circuit is configured to compensate for a voltage drop in a three-phase AC line when three-phase AC power is supplied from the inverter to an AC load. A corrector is configured to correct the output voltage command value Vor* based on a compensation command value Vol. A control circuit is configured to control the inverter based on an output voltage command value Vo* corrected by the corrector.

Abstract: An uninterruptible power supply system includes a regular uninterruptible power supply device configured to supply AC power to a load, and an auxiliary power conversion device configured to supply AC power to the load when the regular uninterruptible power supply device has a failure. The auxiliary power conversion device includes a converter and an inverter. When a DC voltage generated by the converter is higher than a lower limit voltage, the auxiliary power conversion device outputs an AC voltage having a sinusoidal wave and falling within an acceptable input voltage range of the load. When the DC voltage is lower than the lower limit voltage, the auxiliary power conversion device outputs an AC voltage having waveform distortion within an acceptable range for the load and falling within the acceptable input voltage range of the load.

Abstract: An uninterruptible power supply device includes: an inverter configured to convert AC power from an AC power supply into DC power and output the DC power to a DC bus; a converter configured to convert the DC power received from the DC bus into AC power and supply the AC power to a load; a bidirectional chopper configured to transmit and receive DC power between the DC bus and a storage battery; a bidirectional chopper configured to transmit and receive DC power between the DC bus and a lithium ion battery; a controller configured to cause the storage battery to be charged during normal operation, and to be discharged during power failure; and a controller configured to cause the lithium ion battery to be charged when the load is performing a regenerative operation, and to be discharged when the load is performing a power running operation.

Abstract: During power running operation of a load, a control unit turns off a switch unit to supply AC power from an uninterruptible power supply unit to the load. During regenerative operation of the load, in a case where an AC power supply can recover regenerative power, the control unit turns off the switch unit to supply the regenerative power to the AC power supply via the uninterruptible power supply unit. In contrast, in a case where the AC power supply cannot recover the regenerative power, the control unit turns on the switch unit to cause an auxiliary load unit to consume the regenerative power.

Abstract: An uninterruptible power supply apparatus (1) drives a converter (6) at a relatively high frequency (fH) and supplies an output voltage (VDC) of the converter (6) directly to a load (23) when a load current (IL) is greater than a predetermined value (Ic), and drives the converter (6) at a relatively low frequency (fL), steps up the output voltage (VDC) of the converter (6) by a bidirectional chopper (11), and supplies the output voltage (VDC) of the converter (6) to the load (23) when the load current (IL) is smaller than the predetermined value (Ic).

Abstract: A generation circuit is configured to generate an output voltage command value Vor* for an inverter based on a three-phase reference value Vr, a zero-phase reference value, a detected value of a current sensor, and a detected value of a voltage sensor. A compensation circuit is configured to compensate for a voltage drop in a three-phase AC line when three-phase AC power is supplied from the inverter to an AC load. A corrector is configured to correct the output voltage command value Vor* based on a compensation command value Vol. A control circuit is configured to control the inverter based on an output voltage command value Vo* corrected by the corrector.

Abstract: When a load current is larger than a predetermined value, a control device of an uninterruptible power supply device controls an inverter by gate signals having a relatively high frequency and having controlled pulse widths, and when the load current is smaller than the predetermined value, the control device controls the inverter by the gate signals having a relatively low frequency and having fixed pulse widths. Therefore, when a load is a light load, switching losses occurring in IGBTs of the inverter can be decreased.

Abstract: An uninterruptible power supply apparatus (1) drives a converter (6) at a relatively high frequency (fH) and supplies an output voltage (VDC) of the converter (6) directly to a load (23) when a load current (IL) is greater than a predetermined value (Ic), and drives the converter (6) at a relatively low frequency (fL), steps up the output voltage (VDC) of the converter (6) by a bidirectional chopper (11), and supplies the output voltage (VDC) of the converter (6) to the load (23) when the load current (IL) is smaller than the predetermined value (Ic).

Abstract: A control device of an uninterruptible power supply device is configured to perform a mode selected from a normal operation mode in which a frequency of a triangular wave signal is set to a relatively high frequency and a power saving operation mode in which the frequency of the triangular wave signal is set to a relatively low frequency. Therefore, by selecting the power saving operation mode in the case of driving a load having a large acceptable range for a voltage fluctuation rate of an AC output voltage, switching losses occurring in IGBTs of an inverter can be decreased.

Abstract: An uninterruptible power supply apparatus supplies AC power from any one of a first inverter of a first power conversion device and a second inverter of a second power conversion device to a load, and when this inverter has a malfunction, the uninterruptible power supply apparatus supplies the AC power from the other inverter to the load. When a DC voltage provided to the second inverter is higher than a lower limit voltage, the second power conversion device outputs an AC voltage having a sinusoidal waveform and falling within an acceptable input voltage range of the load, and when the DC voltage is lower than the lower limit voltage, the second power conversion device outputs an AC voltage having waveform distortion within a range acceptable to the load and falling within the acceptable input voltage range of the load.

Abstract: In an uninterruptible power supply device for supplying DC power to a load, a control device is configured such that, when the load is performing power running operation, the control device turns on a second switch to supply DC power from a diode rectifier to the load, turns off a first switch, and controls a converter to suppress a harmonic current contained in an AC current flowing from an AC power supply to the diode rectifier, and when the load is performing regenerative operation, the control device turns off the second switch, turns on the first switch, and controls the converter to convert regenerative power generated by the load into AC power.

Abstract: An uninterruptible power supply device includes N UPS modules connected in parallel with one another between an AC power supply and a load, a current detector configured to detect a load current, and a controller configured to select n UPS modules, and an auxiliary UPS module, based on a result of detection by the current detector. Each of the n UPS modules is configured to supply, to the load, a shared current which is 1/n of the load current. The auxiliary UPS module is configured to output, to the load, a counter voltage having a value in accordance with output voltages of the n UPS modules, and thereby to stand by in a state where no current flows between the auxiliary UPS module and the n UPS modules and between the auxiliary UPS module and the load.

Abstract: During power running operation of a load, a control unit turns off a switch unit to supply AC power from an uninterruptible power supply unit to the load. During regenerative operation of the load, in a case where an AC power supply can recover regenerative power, the control unit turns off the switch unit to supply the regenerative power to the AC power supply via the uninterruptible power supply unit. In contrast, in a case where the AC power supply cannot recover the regenerative power, the control unit turns on the switch unit to cause an auxiliary load unit to consume the regenerative power.