JP7415703B2 - DC uninterruptible power supply and control method for DC uninterruptible power supply - Google Patents

Description

The present invention relates to a DC uninterruptible power supply and a control method for the DC uninterruptible power supply, and particularly to a DC uninterruptible power supply that includes a bypass section that outputs AC power input from outside the device and a control method for the DC uninterruptible power supply. Regarding the method.

BACKGROUND ART Conventionally, an AC uninterruptible power supply device is known that includes a bypass circuit that outputs AC power input from outside the device (see, for example, Patent Document 1).

The above-mentioned Patent Document 1 describes a PWM converter that converts AC power from an AC power source external to the device into DC power, and a PWM converter that converts the DC power output from the PWM converter or the DC power from a battery into AC power and converts the DC power output from the PWM converter into AC power. An AC uninterruptible power supply device is disclosed that includes an inverter that supplies (outputs) to a load, and a bypass circuit connected between an AC power source external to the device and a load external to the device. In the AC uninterruptible power supply device described in Patent Document 1, during normal times (when AC power is normally supplied from the AC power source), AC power generated by the inverter is supplied to a load outside the device, and the inverter The device is configured to supply AC power from the AC power source to a load outside the device via a bypass circuit in the event of a failure.

Although it is not explicitly stated in Patent Document 1, in the conventional AC uninterruptible power supply device as described in Patent Document 1, during the bypass switching operation to switch with the bypass circuit, inrush current from the bypass circuit side and In order to suppress load fluctuations due to loads external to the device, the phase of the output voltage from the inverter is shifted, and the current is shared from the state where the current is being output from the inverter to the state where the current is being output from the bypass circuit. It is controlled to move gradually. That is, control is performed to reduce the amount of current from the inverter and increase the amount of current from the bypass circuit.

Furthermore, conventional DC uninterruptible power supplies include a PWM converter that converts AC power from an AC power source external to the device into DC power, and a bypass circuit connected between the AC power source external to the device and the load external to the device. Are known. A DC uninterruptible power supply converts AC power from an AC power source external to the device into DC power using a PWM converter, and supplies the DC power output from the PWM converter or the DC power from a battery to a load external to the device. Alternatively, the AC power source is configured to convert AC power from an AC power source into DC power using a rectifier provided in a bypass circuit, and to supply the DC power to a load outside the device.

International Publication No. 2017/094142

Here, in the DC uninterruptible power supply, the output from the bypass circuit and the output from the PWM converter are both DC power, so depending on the voltage level, the output from the bypass circuit and the output from the PWM converter may differ. The current sharing between them is determined. Therefore, in a DC uninterruptible power supply that converts AC power into DC power using a PWM converter, a state in which current is output from the PWM converter as in the conventional AC uninterruptible power supply as described in Patent Document 1 mentioned above is avoided. When performing control to gradually shift the current share from the bypass circuit to the state where current is output, if the output voltage from the bypass circuit is lower than the output voltage from the PWM converter, the output voltage from the PWM converter It is necessary to reduce the voltage to follow the output voltage from the bypass circuit.

However, in the PWM converter, in principle, the upper limit value of the AC input that can be input to the PWM converter changes depending on the DC voltage output from the PWM converter. Specifically, as the voltage output from the PWM converter decreases, the upper limit value of AC input that can be input from AC power external to the device decreases. Therefore, when reducing the output voltage from the PWM converter to match the output voltage from the bypass circuit, the upper limit of the AC input voltage that can be input to the PWM converter becomes lower than the voltage of the AC power external to the device. In this case, the peak portion of the waveform of the sine wave that is input to the PWM converter from the AC power external to the device is collapsed, and only a portion of the AC power external to the device can be input to the PWM converter.

As a result, if the peak part of the sine wave waveform becomes more distorted and the difference between the upper limit of the AC input voltage that can be input to the PWM converter and the voltage of AC power outside the device becomes too large, the output from the PWM converter becomes too large. Voltage control becomes difficult. Therefore, the output voltage from the PWM converter is made to match (follow) the output voltage from the bypass circuit, and the current sharing is gradually shifted from a state where current is being output from the PWM converter to a state where current is being output from the bypass circuit. It becomes difficult to control the That is, it becomes difficult to perform control to decrease the amount of current from the PWM converter and increase the amount of current from the bypass circuit. As a result, there may be a problem in that it is not possible to suppress an increase in load fluctuations due to loads external to the device, and bypass switching cannot be performed. Therefore, even in a DC uninterruptible power supply that converts AC power into DC power using a PWM converter, it is desired to suppress load fluctuations with respect to a load external to the device during a bypass switching operation.

This invention has been made to solve the above-mentioned problems, and one object of the invention is to convert AC power into DC power using a PWM converter, and to reduce the load outside the device during bypass switching operation. An object of the present invention is to provide a DC uninterruptible power supply and a control method for the DC uninterruptible power supply capable of suppressing load fluctuations.

In order to achieve the above object, a DC uninterruptible power supply device according to a first aspect of the present invention includes a PWM converter that converts AC power input from outside the device into DC power and outputs the DC power by PWM control, and a battery that outputs the DC power. A power converter unit includes a buck-boost unit whose output side is connected to the output side of the PWM converter, and which outputs the converted DC power by boosting or stepping down the voltage and outputs the DC power. a bypass section including a bypass rectifier that converts the converted AC power into DC power and outputs it, and a bypass power switching operation that switches the output to the load outside the device from the output of the power conversion section to the output of the bypass section or the load outside the device. During at least one of the power converter feeding switching operations in which the output to the bypass unit is switched from the output of the bypass unit to the output of the power converter, the first current value that is the current value of the output current from the bypass unit or the bypass unit a control unit configured to perform control to change a second output voltage, which is the output voltage from the buck-boost unit, based on at least one of the first output voltage, which is the output voltage from the buck-boost unit. .

As described above, the DC uninterruptible power supply according to the first aspect boosts or steps down the DC power output from the battery and outputs the voltage, and also includes a buck-boost section whose output side is connected to the output side of the PWM converter. A power conversion unit including a power conversion unit is provided. Then, during at least one of the bypass power supply switching operation for switching to the output of the bypass section or the power conversion section power supply switching operation for switching to the output of the power conversion section, a first current that is the current value of the output current from the bypass section is generated. The second output voltage, which is the output voltage from the step-up/down section, is controlled to be changed based on at least either the value or the first output voltage, which is the output voltage from the bypass section. This allows the buck-boost section, which steps up or steps down the DC power output from the battery and outputs the voltage, to adjust the output voltage from the power conversion section. Unlike the case of using a PWM converter in which the upper limit value of possible AC input is lowered, the output voltage from the power conversion section can be easily made to follow the first output voltage that is the output voltage from the bypass section. Therefore, the second output voltage, which is the output voltage from the buck-boost section, is changed based on the first current value, which is the current value of the output current from the bypass section, or the first output voltage, which is the output voltage from the bypass section. By increasing the voltage (up or down), it is possible to gradually shift the current share from a state in which current is being output from the power conversion section to a state in which current is being output from the bypass section. As a result, it is possible to provide a DC uninterruptible power supply device that can convert AC power into DC power using a PWM converter and suppress load fluctuations with respect to a load external to the device during a bypass switching operation.

In the DC uninterruptible power supply according to the first aspect, preferably, the control section controls the buck-boost section to step down the voltage of the second output voltage more than the voltage of the first output voltage during the bypass power supply switching operation. The system is configured to perform control such as: With this configuration, during the bypass power supply switching operation, the control section controls the buck-boost section to change the second output voltage, which is the output voltage from the buck-boost section, to the first output voltage, which is the output voltage from the bypass section. can be lower than. As a result, during the bypass power supply switching operation, the output current from the step-up/down section can be reduced, and the first current value, which is the current value of the output current from the bypass section, can be increased.

In the configuration in which the voltage of the second output voltage is controlled to be lower than the voltage of the first output voltage during the power supply switching operation, preferably, the control section controls the output current from the buck-boost section during the bypass power supply switching operation. By stepping down the second output voltage by the step-up/down section based on the difference between the second current value, which is the current value, and the third current value, which is the total value of the first current value and the second current value, It is configured to perform control to change the first current value and the second current value. With this configuration, during the bypass power supply switching operation, the first current value, which is the current value of the output current from the bypass section, can be obtained from the difference between the second current value and the third current value. As a result, by stepping down the second output voltage, which is the output voltage from the buck-boost section, based on the first current value and the second current value, the output of the power conversion section (buck-boost section) can be easily reduced. It is possible to gradually shift the amount of current to the output of the bypass section.

In the configuration in which the second output voltage is stepped down by the buck-boost section based on the difference between the second current value and the third current value, preferably, the second current value is set to a predetermined current value during the bypass power supply switching operation. The configuration is such that the electrical connection between the step-up/down section and the bypass section is disconnected when the following conditions occur. With this configuration, during the bypass power supply switching operation, the second current value, which is the current value of the output current from the buck-boost section, is sufficiently reduced, and the current amount for the load outside the device is shared by the buck-boost section. In a state where the output has sufficiently shifted from the output of the step-up/down section to the output of the bypass section, the output to the load outside the device can be switched from the output of the step-up/down section to the output of the bypass section. As a result, it is possible to further suppress load fluctuations with respect to the load external to the device during the bypass power supply switching operation.

In this case, preferably, after the bypass power supply switching operation, the current path between the PWM converter and the AC power source external to the device is electrically connected to start charging the battery. With this configuration, charging of the battery starts after the bypass power supply switching operation in which power is discharged from the battery, so that after the bypass power supply switching operation, the output to the external load of the device is changed from the output of the bypass section. When performing a power conversion section power supply switching operation of switching to the output of the conversion section, it is possible to prevent the power charged in the battery from running out.

In the DC uninterruptible power supply according to the first aspect, preferably, the control unit controls the buck-boost unit to lower the voltage of the second output voltage than the voltage of the first output voltage during the power conversion unit power supply switching operation. It is configured to perform control to boost the voltage. With this configuration, when switching the power supply to the power conversion unit, the control unit controls the buck-boost unit to change the second output voltage, which is the output voltage from the buck-boost unit, to the first output voltage, which is the output voltage from the bypass unit. It can be higher than the output voltage. As a result, during the bypass power supply switching operation, it is possible to increase the second current value, which is the current value of the output current from the buck-boost section, and to increase the first current value, which is the current value of the output current from the bypass section. can be reduced.

In the configuration that performs control to boost the voltage of the second output voltage more than the voltage of the first output voltage during the power conversion section power supply switching operation, preferably, the control section controls the second output voltage during the power conversion section power supply switching operation. The step-up/down section is configured to step up the second output voltage based on the difference between the current value and the third current value, thereby performing control to change the first current value and the second current value. With this configuration, it is possible to obtain the first current value, which is the current value of the output current from the bypass section, from the difference between the second current value and the third current value when the power conversion section power supply switching operation is performed. can. As a result, by boosting the second output voltage, which is the output voltage from the buck-boost section, based on the first current value and the second current value, it is possible to easily convert the output of the bypass section from the output of the bypass section to the power conversion section (buck-boost It is possible to gradually shift the share of the current amount to the output of the power converter (increase the share of the current in the output from the power converter).

In this case, it is preferably configured to disconnect the electrical connection between the buck-boost section and the bypass section when the first current value becomes equal to or less than a predetermined current value during the power conversion section power supply switching operation. . With this configuration, when switching the power supply to the power conversion section, the first current value, which is the current value of the output current from the bypass section, is sufficiently reduced, and the current amount to be shared with the load outside the device is shared by the bypass section. In a state where the output has sufficiently shifted from the output of the step-up/down section to the output of the step-up/down section, the output to the load outside the device can be switched from the output of the bypass section to the output of the step-up/down section. As a result, it is possible to further suppress load fluctuations with respect to the load external to the device during the power converter feeding switching operation.

In the DC uninterruptible power supply according to the first aspect, preferably, the step-up/down section is a chopper type converter that steps up or steps down the DC power output from the battery and outputs the voltage, and the control section, during the switching operation, Control the chopper type converter to change the second output voltage, which is the output voltage from the chopper type converter, in a state where the current path between the PWM converter and the AC power source outside the device is electrically separated. It is configured as follows. With this configuration, the power from the battery can be stepped up or down more efficiently than when the power from the battery is converted into an isolated DC voltage using a flyback method or the like.

In order to achieve the above object, a method for controlling a DC uninterruptible power supply according to a second aspect of the present invention includes a step-up/down section that steps up or steps down the DC power output from the battery and outputs the voltage, A method for controlling a DC uninterruptible power supply device that outputs DC power to the outside of the device, the bypass section being connected to the output side and converting AC power from an AC power source outside the device into DC power and outputting the same, the method comprising: acquiring a first current value that is the current value of the output current from the bypass section or a first output voltage that is the output voltage of the bypass section; and at least one of the acquired first current value or first output voltage. the step of changing a second output voltage, which is the output voltage from the step-up/down section, based on the step-up/down section.

In the method for controlling a DC uninterruptible power supply according to the second aspect, as described above, the first current value that is the current value of the output current from the bypass section or the first output voltage that is the output voltage of the bypass section is obtained. and a second output voltage from a step-up/down section that steps up or steps down the DC power output from the battery and outputs the step, based on at least one of the acquired first current value and first output voltage. and a step of changing the output voltage. As a result, by using the buck-boost section, which steps up or steps down the DC power output from the battery and outputs it, to adjust the output voltage from the power conversion section, when the voltage to be output is low, it is possible to input AC power from outside the device. Unlike the case of using a PWM converter in which the upper limit value of possible AC input is lowered, the output voltage from the power conversion section can be easily made to follow the first output voltage that is the output voltage from the bypass section. Therefore, the output voltage from the buck-boost section is determined based on at least one of the first current value, which is the obtained current value of the output current from the bypass section, or the first output voltage, which is the output voltage from the bypass section. By changing the second output voltage (stepping up or stepping down), it is possible to gradually shift the current share from a state in which current is being output from the power conversion section to a state in which current is being output from the bypass section. As a result, it is possible to provide a control method for a DC uninterruptible power supply that can convert AC power into DC power using a PWM converter and suppress load fluctuations to external loads during bypass switching operations.

In the method for controlling a DC uninterruptible power supply according to the second aspect, preferably, the step-up/down section is a chopper type converter that steps up or steps down the DC power output from the battery and outputs the second output voltage. The step of changing is a step of changing the second output voltage, which is the output voltage from the chopper converter. With this configuration, in the step of changing the second output voltage, the power from the battery can be boosted or stepped down more efficiently than when the power from the battery is converted into isolated DC voltage using a flyback method or the like. can do.

According to the present invention, as described above, a DC uninterruptible power supply and a DC uninterruptible power supply are capable of converting AC power into DC power using a PWM converter and suppressing load fluctuations with respect to a load external to the device during bypass switching operation. A method for controlling a device can be provided.

1 is a diagram showing the configuration of a DC uninterruptible power supply according to an embodiment of the present invention. FIG. 3 is a diagram for explaining control of a control unit by a DC uninterruptible power supply according to an embodiment of the present invention. FIG. 7 is a first flowchart for explaining an example of processing of the control unit during bypass power supply switching operation. FIG. It is a 2nd flowchart for demonstrating an example of the process of a control part at the time of a bypass power supply switching operation. FIG. 2 is a first flowchart for explaining an example of processing of a control unit during a power conversion unit power feeding switching operation; FIG. 12 is a second flowchart for explaining an example of the processing of the control section during the power conversion section power feeding switching operation.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments embodying the present invention will be described based on the drawings.

(Overall configuration of DC uninterruptible power supply)
With reference to FIG. 1, the configuration of a DC uninterruptible power supply 100 according to this embodiment will be described.

The DC uninterruptible power supply 100 according to this embodiment is an uninterruptible power supply (UPS) or PCS (Power Conditioning System) that outputs DC power to a load 200 outside the device. The DC uninterruptible power supply 100 is a device that converts AC power from an AC power source 201 (AC power source 202) outside the device and outputs DC power to a load 200 outside the device. Then, when AC power is not supplied from the AC power source 201 external to the device, such as during a power outage, the DC uninterruptible power supply 100 converts the output power from the battery 40 external to the device and supplies it to the load 200 external to the device. It is an output device. Note that the battery 40 may be provided inside the device.

The DC uninterruptible power supply 100 includes a power conversion section 10, a bypass section 20, and a control section 30. Power conversion section 10 includes a PWM converter 11 and a buck-boost section 12. Further, power conversion section 10 includes an electrolytic capacitor C1 and fuses F1, F2, and F3.

The PWM converter 11 is configured to convert AC power input from outside the device into DC power by PWM control and output the DC power. Specifically, the PWM converter 11 is a three-phase voltage converter using a pulse width modulation (PWM) control method, and converts AC power from an AC power supply 201 external to the device into DC power and outputs the DC power. It is configured as follows.

An AC input switch 51 is provided between the PWM converter 11 of the power converter 10 and an AC power supply 201 external to the device. The AC input switch 51 can be switched between a state in which the current path between the PWM converter 11 and the AC power source 201 outside the device is electrically connected (ON state) and a state in which it is electrically disconnected (OFF state). It is configured.

Furthermore, a reactor L1, a capacitor C2, and a reactor L2 are provided between the AC input switch 51 and the power converter 10 in this order from the AC input switch 51 side. Further, a fuse F1 is provided between the PWM converter 11 and the reactor L2.

The step-up/down section 12 is configured to step up or step down the DC power output from the battery 40 and output the voltage. Further, the step-up/down section 12 is configured such that its output side is connected to the output side of the PWM converter 11. The step-up/down section 12 is configured to step up or step down the DC power output from the PWM converter 11 and output the voltage to charge the battery 40 . That is, the buck-boost section 12 is configured to be able to input and output DC power in both directions (to the battery 40 or the PWM converter 11).

The step-up/down section 12 is a chopper converter that steps up or steps down the DC power output from the battery 40 and outputs the voltage. Specifically, the buck-boost unit 12 is a buck-boost chopper bidirectional DC/DC converter configured to boost or step down the DC power output from the battery 40 and output the voltage.

A battery input switch 52 is provided between the step-up/down section 12 of the power conversion section 10 and the battery 40. The battery input switch 52 is configured to be able to switch between a state in which the current path between the buck-boost unit 12 and the battery 40 is electrically connected (ON state) and a state in which the current path is electrically disconnected (OFF state). There is.

A capacitor C3 and a reactor L3 are provided between the battery input switch 52 and the power converter 10 in this order from the AC input switch 51 side. Further, a fuse F3 is provided between the voltage step-up/down section 12 and the reactor L3.

Further, a diode D and a UPS output switch 53 are provided between the power converter 10 and a load 200 outside the device, in this order from the output side of the power converter 10. The UPS output switch 53 is in a state in which the current path between the power conversion unit 10 (PWM converter 11 and buck-boost unit 12) and the output from the bypass unit 20 (load 200 outside the device) is electrically connected (ON state). ) and an electrically disconnected state (OFF state).

Further, a fuse F2 is provided between the PWM converter 11 (buck-boost section 12) and the diode D, and an electrolytic capacitor is provided between the PWM converter 11 (buck-boost section 12) and the fuse F2. C1 is provided.

In the present embodiment, the bypass section 20 is connected to the output side of the power conversion section 10 (the output side of the buck-boost section 12), and a bypass rectifier 21 that converts AC power input from outside the device into DC power and outputs the DC power. including. Further, the bypass section 20 is provided with a semiconductor switch SW, a reactor L4, and a bypass switch 22. The bypass switch 22 can be switched between a state in which the current path between the bypass rectifier 21 and the AC power source 202 outside the device is electrically connected (ON state) and a state in which it is electrically disconnected (OFF state). It is configured.

The bypass rectifier 21 is a three-phase full-wave type rectifier, and is configured to convert AC power input from an AC power supply 202 outside the device into DC power and output the DC power.

Bypass switch 22 and semiconductor switch SW are arranged between AC power supply 202 outside the device and bypass rectifier 21, and reactor L4 is arranged between bypass switch 22 and semiconductor switch SW and bypass rectifier 21. has been done.

The control section 30 controls the step-up and step-down (step-up and step-down) of the power by the step-up and step-down section 12 by controlling a gate drive circuit 60 that drives the gate of the step-up and step-down section 12 based on control described below. It is composed of The control unit 30 includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM (Random Access Memory).

The DC uninterruptible power supply 100 is provided with current detection units 71 and 72. Current detection units 71 and 72 are configured to detect current in a current path of DC uninterruptible power supply 100. The current detection units 71 and 72 are configured to output current detection results to the control unit 30. Current detection units 71 and 72 include Hall CTs (Current Transformers) and the like.

The current detection section 71 is configured to detect a current value I _DC that is the current value of the output current from the step-up/down section 12 (power conversion section 10). Note that the current value I _DC is an example of a "second current value" in the claims.

The current detection unit 72 is configured to detect a current value I _OUT that is the current value of the output current output from the DC uninterruptible power supply 100 to the load 200 outside the device. Note that the current value I _OUT is an example of a "third current value" in the claims.

Further, the current value I _OUT , which is the current value of the output current output from the DC uninterruptible power supply 100 to the load 200 outside the device, is the current value of the output current from the buck-boost unit 12 (power conversion unit 10). This is the total value of the current value I _DC which is , and the current value I _Byp which is the current value of the output current from the bypass section 20 . Thereby, the current value I _Byp can be calculated from the difference between the current value I _OUT and the current value I _DC . Note that the current value I _Byp is an example of a "first current value" in the claims.

Further, the DC uninterruptible power supply 100 is provided with voltage detection sections 81, 82, and 83. The voltage detection units 81 to 83 are configured to detect the voltage in the current path of the DC uninterruptible power supply 100. The voltage detection units 81 , 82 , and 83 are configured to output voltage detection results to the control unit 30 . The voltage detection units 81 to 83 include a shunt resistor, a Hall CT (Current Transformer), and the like.

Voltage detection section 81 is configured to detect output voltage V _BAT that is the output voltage from battery 40 .

The voltage detection section 82 is configured to detect the output voltage V _DC that is the output voltage from the step-up/down section 12 (power conversion section 10). Note that the output voltage V _DC is an example of a "second output voltage" in the claims.

The voltage detection unit 83 is configured to detect an output voltage V _OUT that is an output voltage output from the DC uninterruptible power supply 100 to a load 200 outside the device.

Further, the output voltage V _OUT , which is the output voltage output from the DC uninterruptible power supply 100 to the load 200 outside the device, is the output voltage V _DC , which is the output voltage from the buck-boost unit 12 (power conversion unit 10). and the output voltage V _Byp , which is the output voltage from the bypass section 20. Thereby, the output voltage V _Byp can be calculated from the difference between the output voltage V _OUT and the output voltage V _DC . Note that the output voltage V _Byp is an example of a "first output voltage" in the claims.

(Configuration of control unit)
Next, the configuration for controlling the switching operation of the control section 30 in this embodiment will be described with reference to FIG. 2.

The control unit 30 determines a current value, which is the current value of the output current from the bypass unit 20, from the difference between the current value I _DC detected by the current detection unit 71 and the current value I _OUT detected by the current detection unit 72. Calculate I _Byp . Then, current sharing control is performed based on the calculated current value I _Byp and the output current command I _DC[ref] . The current sharing control is a control for bringing the current value I _Byp closer to a target value of the output current output from the step-up/down section 12, and is performed by PI control (proportional/integral control). Through the current sharing control, an output current command value that is a command value for bringing the output current output from the step-up/down section 12 closer to a target value is output.

When the current value I _Byp is lower than the output current command I _DC[ref] , the command value (output current command value) for stepping down the output voltage V _DC , which is the output voltage from the buck-boost unit 12, is When the current value I _Byp is higher than the output current command, a command value (output current command value) for boosting the output voltage V _DC , which is the output voltage from the buck-boost unit 12, is output. Ru.

The control unit 30 determines the output voltage V Byp, which is the output voltage from the bypass unit 20, from the difference between the output voltage V _DC detected by the voltage detection unit 82 and the output voltage V _OUT detected by the voltage detection unit ₈₃ . calculate. Then, based on the calculated output voltage V _Byp and the output voltage command V _DC[ref] , an output voltage command value, which is a command value for bringing the output voltage output from the buck-boost unit 12 closer to the target value, is determined. Output.

Then, the control unit 30 performs output constant voltage control based on the output current command value and the output voltage command value. Output constant voltage control is control for keeping the output voltage constant, and is performed by droop control.

Further, the control unit 30 controls the output voltage from the battery 40 based on the output voltage V _BAT detected by the voltage detection unit 81 and the set value of the output voltage from the battery 40 (output voltage command V _BAT[ref] ). A battery voltage command value is output, which is a command value for bringing the output voltage closer to the target value.

Next, the control unit 30 performs battery constant voltage control. Battery constant voltage control is control for adjusting the input side of voltage step-up/down section 12 in order to prevent rapid discharge with respect to the battery voltage command value and the result of output constant voltage control, and is performed by PI control.

Then, the control unit 30 performs a λ (lambda) calculation on the result obtained by battery constant voltage control, and then uses a gate drive circuit 60 that drives the gate of the buck-boost unit 12 using a control signal obtained by performing PWM conversion. is controlled by PWM. Thereby, the voltage step-up/down section 12 is controlled to control the step-up/down of the output voltage V _DC , which is the output voltage from the step-up/down section 12 . The response speed of the control by the control unit 30 described above follows the time constant set in each control block, and is performed slowly so as not to cause large fluctuations in the output voltage.

Further, the control unit 30 performs bypass voltage follow-up control during the switching operation (the bypass power supply switching operation and the power converter power supply switching operation) based on the control shown in FIG. 2 . The bypass voltage follow-up control is a control that refers to the bypass input voltage (output voltage from the AC power supply 202) and adjusts the output voltage V _DC to a predetermined value.

In the present embodiment, the control unit 30 controls the current value of the output current from the bypass unit 20, I _Byp , or It is configured to perform control to change V _DC , which is the output voltage from the step-up/down section 12, based on at least one of the output voltages, V _Byp .

Specifically, during the switching operation, the control unit 30 controls the buck-boost unit 12 (chopper type converter) in a state where the current path between the PWM converter 11 and the AC power supply 201 outside the device is electrically disconnected. The converter is configured to perform control to change the output voltage V _DC , which is the output voltage from the step-up/down section 12 (chopper type converter). That is, in a battery operating state in which the operation of the PWM converter 11 is stopped and the output power from the battery 40 is output to the load 200 outside the device via the buck-boost section 12, the power converter 10 (step-up/step-down section 12) is operated. It is configured to share the load of the amount of current between the output and the output from the bypass section 20.

The bypass power supply switching operation is an operation of switching the output to the load 200 outside the device from the output of the power converter 10 to the output of the bypass unit 20. Specifically, the bypass power supply switching operation is a switching operation performed during maintenance of the DC uninterruptible power supply 100, and changes the output to the load 200 outside the device from the output of the power conversion unit 10 to the bypass unit 20. This is a switching operation to switch to the output (output from the AC power supply 202 outside the device).

Further, the power conversion section power supply switching operation is an operation of switching the output to the load 200 outside the device from the output of the bypass section 20 to the output of the power conversion section 10. Specifically, the bypass power supply switching operation is a switching operation performed when returning the DC uninterruptible power supply 100 to normal operation after maintenance of the DC uninterruptible power supply 100 is completed, and is a switching operation that is performed when returning the DC uninterruptible power supply 100 to normal operation. This is a switching operation in which the output of the bypass unit 20 (output from the AC power supply 202 external to the device) is switched to the output of the power converter 10 to be output to the load 200 external to the device.

(Control during bypass power supply switching operation)
During the bypass power supply switching operation, the control section 30 is configured to control the step-up/down section 12 to perform control such that the voltage of the output voltage V _DC is lower than the voltage of the output voltage V _Byp .

During the bypass power supply switching operation, the control unit 30 switches to battery operation in which the output power from the battery 40 is output to the load 200 outside the device via the step-up/down unit 12 in order to start bypass voltage follow-up control. . Then, the control section 30 controls the voltage step-up/down section 12 so that the output from the power conversion section 10 (step-up/down section 12) is the same predetermined voltage as during normal battery operation. Thereby, all of the output to the load 200 outside the device is made to be the output from the power converter 10 (step-up/step-down section 12). Then, the control unit 30 turns on the bypass switch 22 while outputting the same predetermined voltage as during normal battery operation, and performs control to step down the output voltage V _DC in accordance with the target current command value.

During the bypass power supply switching operation, the control unit 30 controls a current value I _DC that is the current value of the output current from the buck-boost unit 12, and a current value I _OUT that is the sum of the current value I _Byp and the current value I _DC . The step-up/down section 12 steps down the output voltage V _DC based on the difference (current value I _Byp ), thereby performing control to change the current value I _Byp and the current value I _DC .

The DC uninterruptible power supply 100 also disconnects the electrical connection between the buck-boost section 12 and the bypass section 20 when the current value I _DC becomes equal to or less than a predetermined current value during the bypass power supply switching operation. It is configured. Specifically, under the control of the control unit 30, the DC uninterruptible power supply 100 controls when the current value I _DC becomes equal to or less than a predetermined current value, that is, when the current value I _DC becomes sufficient for the current value I _Byp. is configured to turn off the UPS output switch 53 and switch the output power from the DC uninterruptible power supply 100 to the output from the bypass section 20 when the load fluctuation reaches a value that can be sufficiently suppressed. There is. Note that the predetermined current value is a value that can sufficiently suppress load fluctuations. The predetermined current value is, for example, about 10% to 20% of the current value I _Byp .

The DC uninterruptible power supply 100 is configured to electrically connect the current path between the PWM converter 11 and the AC power supply 201 external to the device to start charging the battery 40 after the bypass power supply switching operation. There is. Specifically, after the bypass power supply switching operation, the DC uninterruptible power supply 100 turns on the AC input switch 51 under the control of the control unit 30, returns the PWM converter 11 to the operating state, and supplies power to the battery 40. configured to start charging.

(Control during power conversion section power supply switching operation)
In this embodiment, the control unit 30 is configured to control the buck-boost unit 12 to boost the voltage of the output voltage V _DC more than the voltage of the output voltage V _Byp during the power conversion unit feeding switching operation. has been done.

In the power conversion unit power supply switching operation, the control unit 30 switches to battery operation in which the output power from the battery 40 is output to the load 200 outside the device via the step-up/down unit 12 in order to start bypass voltage follow-up control. Switch. Then, the control section 30 controls the voltage step-up/down section 12 so that the output from the power conversion section 10 (step-up/down section 12) is the same predetermined voltage as during normal battery operation. Then, the control section 30 controls the voltage step-up/down section 12 to step down the output voltage V _DC from the voltage step-up/down section 12 to a predetermined initial value. Note that the predetermined initial value when stepping down the output voltage V _DC of the step-up/down section 12 is less than or equal to the minimum value of the output voltage from the bypass rectifier 21 . For example, it is 1.2 times or less the effective value of the bypass input voltage (AC). Furthermore, the step-down to a predetermined initial value may be performed when switching to battery operation. Then, the control unit 30 turns on the UPS output switch 53 and performs control to boost the output voltage V _DC according to the target current command value.

The control unit 30 increases the current value I _Byp and the current value by boosting the output voltage V _DC by the buck-boost unit 12 based on the difference between the current value I DC and the current value I _OUT (current value I _{Byp )} . It is configured to perform control to change I _DC .

Further, the DC uninterruptible power supply 100 disconnects the electrical connection between the buck-boost section 12 and the bypass section 20 when the current value I _Byp becomes equal to or less than a predetermined current value during the power conversion section power supply switching operation. It is configured as follows. Specifically, under the control of the control unit 30, the DC uninterruptible power supply 100 controls when the current value I _Byp becomes equal to or less than a predetermined current value, that is, when the current value I _Byp becomes sufficient for the current value I _DC . The UPS output switch 53 is turned OFF when the load fluctuation reaches a value that is small enough to suppress the load fluctuation, and the output power from the DC uninterruptible power supply 100 is changed to the output from the power conversion unit 10. ing. Note that the predetermined current value is a value that can sufficiently suppress load fluctuations. The predetermined current value is, for example, about 10% to 20% of the current value I _DC .

(Processing during bypass power supply switching operation)
Next, with reference to FIGS. 3 and 4, an example of control processing performed by the control unit 30 of the present embodiment during the bypass power supply switching operation will be described based on a flowchart. Note that control by the control unit 30 during a series of bypass power supply switching operations is started based on an operation for starting the bypass power supply switching operation.

Note that at the start of the bypass power supply switching operation, the AC input switch 51, the battery input switch 52, and the UPS output switch 53 are in the ON state. Moreover, the bypass switch 22 is in an OFF state. The PWM converter 11 and the step-up/down section 12 are in operation, and the battery 40 is being charged.

In step S1, the control unit 30 determines whether the output voltage (bypass voltage) V _Byp is within the rated range. If the control unit 30 determines that the output voltage V _Byp is not within the rated range, the processing step moves to step S2. If the control unit 30 determines that the output voltage V _Byp is within the rated range, the processing step moves to step S3.

In step S2, the control unit 30 refuses to accept the operation for starting the bypass power supply switching operation. After completion of step S2, the processing steps return to step S1.

In step S3, the control unit 30 receives an operation for starting the bypass power supply switching operation. After receiving the operation, the processing step moves to step S4.

In step S4, the control unit 30 performs control to turn off the AC input switch 51, stop the PWM converter 11, and perform control to switch to the battery operation mode. Then, the control unit 30 controls the output power from the battery 40 to be boosted by the voltage step-up/down unit 12 .

In step S5, the control unit 30 turns on the bypass switch 22. By turning on the bypass switch 22, the output from the power conversion section 10 (step-up/down section 12) and the output from the bypass section 20 are matched (merged). At this time, the output voltage V _DC , which is the output voltage from the step-up/down section 12, is higher than the output voltage V _Byp, which is the output voltage from the bypass section 20.

In step S6, the control unit 30 performs bypass voltage follow-up control. In step S7, the control unit 30 obtains a current value I _Byp , which is the current value of the output current from the bypass unit 20, and an output voltage V _Byp , which is the output voltage from the bypass unit 20. Then, the control unit 30 refers to the bypass input voltage (output voltage from the AC power supply 202) based on the acquired current value I _Byp and output voltage V _Byp , and performs bypass voltage tracking to adjust the output voltage V _DC to a predetermined value. Take control.

In step S7, the control unit 30 performs current sharing control. The control section 30 controls the step-up/down section 12 to gradually decrease the output voltage V _DC and increase the amount of current from the bypass section 20 . In step S7, the control section 30 continues to obtain the current value I _Byp and the output voltage V _Byp , and the output voltage from the buck-boost section 12 is determined based on the obtained current value I _Byp and output voltage V _Byp . The output voltage V _DC is changed.

In step S8, the control unit 30 determines whether the current value I _DC is less than or equal to a predetermined current value. If the control unit 30 determines that the current value I _DC is less than or equal to the predetermined current value, the process proceeds to step S9. Note that the predetermined current value is a value that can sufficiently suppress load fluctuations. The predetermined current value is, for example, about 10% to 20% of the current value I _Byp . If the control unit 30 determines that the current value I _DC is not equal to or less than the predetermined current value, step S8 is repeated.

In step S9, the control unit 30 performs control to turn off the UPS output switch 53.

In step S10, the control unit 30 performs control to turn on the AC input switch 51, and performs control to start (restart) the operation of the PWM converter 11. Charging of the battery 40 is started by starting (restarting) the operation of the PWM converter 11.

(Processing during power conversion section power supply switching operation)
Next, with reference to FIGS. 5 and 6, an example of control processing performed by the control section 30 of the present embodiment during the power conversion section power feeding switching operation will be described based on a flowchart. Note that the control by the control unit 30 during a series of power conversion section power supply switching operations is started based on an operation for starting the power conversion section power supply switching operation.

Note that at the start of the power conversion section power supply switching operation, the AC input switch 51, the battery input switch 52, and the bypass switch 22 are in the ON state. Further, the UPS output switch 53 is in an OFF state. The PWM converter 11 and the step-up/down section 12 are in operation, and the battery 40 is being charged or discharged.

In step S101, the control unit 30 determines whether the AC input voltage from the AC power supply 201 external to the device is within the rated range. If the control unit 30 determines that the AC input voltage is not within the rated range, the process proceeds to step S102. If the control unit 30 determines that the AC input voltage is within the rated range, the process proceeds to step S103.

In step S102, the control unit 30 refuses to accept the operation for starting the power conversion unit power feeding switching operation. After completion of step S102, the processing step returns to step S101.

In step S103, the control unit 30 receives an operation for starting the power conversion unit power feeding switching operation. After receiving the operation, the processing step moves to step S4.

In step S104, the control unit 30 performs control to turn off the AC input switch 51, stop the PWM converter 11, and perform control to switch to the battery operation mode. Then, the control unit 30 controls the output power from the battery 40 to be boosted by the voltage step-up/down unit 12 .

In step S105, the control unit 30 performs bypass voltage follow-up control. In step S105, the control unit 30 obtains a current value I _Byp that is the current value of the output current from the bypass unit 20 and an output voltage V _Byp that is the output voltage from the bypass unit 20. Then, the control unit 30 refers to the bypass input voltage (output voltage from the AC power supply 202) based on the acquired current value I _Byp and output voltage V _Byp , and performs bypass voltage tracking to adjust the output voltage V _DC to a predetermined value. Take control. The processing step then moves to step S106.

In step S106, the control unit 30 turns on the UPS output switch 53. By turning on the UPS output switch 53, the output from the power conversion section 10 (step-up/down section 12) and the output from the bypass section 20 are matched (merged). At this time, the output voltage V _DC , which is the output voltage from the step-up/down section 12, is lower than the output voltage V _Byp, which is the output voltage from the bypass section 20.

In step S107, the control unit 30 performs current sharing control. The control section 30 controls the step-up/down section 12 to gradually increase the output voltage V _DC and decrease the amount of current from the bypass section 20 . In step S107, the control unit 30 continues to acquire the current value I _Byp and the output voltage V _Byp , and the output voltage from the buck-boost unit 12 is determined based on the acquired current value I _Byp and output voltage V _Byp . The output voltage V _DC is changed.

In step S108, the control unit 30 determines whether the difference between the current value I _OUT and the current value I _DC is less than or equal to a predetermined current value. That is, it is determined whether the current value I _Byp is less than or equal to a predetermined current value. If the control unit 30 determines that the difference between the current value I _OUT and the current value I _DC (current value I _Byp ) is less than or equal to the predetermined current value, the processing step moves to step S109. Note that the predetermined current value is a value that can sufficiently suppress load fluctuations. The predetermined current value is, for example, about 10% to 20% of the current value I _DC . If the control unit 30 determines that the difference between the current value I _OUT and the current value I _DC (current value I _Byp ) is not equal to or less than the predetermined current value, step S108 is repeated.

In step S109, the control unit 30 performs control to turn off the bypass switch 22.

In step S110, the control unit 30 performs control to turn on the AC input switch 51, and performs control to start (restart) the operation of the PWM converter 11. Then, the control unit 30 starts (restarts) the operation of the PWM converter 11, so that the PWM converter 11 converts the power from the AC power supply 201 outside the device, and outputs it to the load 200 outside the device. Output (charging) to the battery 40 is started.

(Effects of this embodiment)
In this embodiment, the following effects can be obtained.

In the present embodiment, the control unit 30 controls the current value I _Byp , which is the current value of the output current from the bypass unit 20, and the output from the bypass unit 20 during the switching operation of the bypass power supply switching operation and the power conversion unit power supply switching operation. Control is performed to change the output voltage V _DC , which is the output voltage from the step-up/down section 12, based on the output voltage V _Byp , which is the voltage. As a result, by using the step-up/down section 12, which steps up or steps down the DC power output from the battery 40 and outputs it, to adjust the output voltage from the power conversion section 10, when the output voltage is low, the Unlike when using a PWM converter 11 in which the upper limit value of AC input that can be inputted from electric power is lowered, the output voltage from the power converter 10 can be easily made to follow the output voltage V _Byp that is the output voltage from the bypass unit 20. I can do it. Therefore, based on the current value I _Byp that is the current value of the output current from the bypass section 20 or the output voltage V _Byp that is the output voltage from the bypass section 20, the output voltage V _DC that is the output voltage from the buck-boost section 12 is determined. By changing the voltage (stepping up or stepping down), it is possible to gradually shift the current share from a state where current is being output from the power converter 10 to a state where current is being output from the bypass section 20. As a result, the DC uninterruptible power supply 100 and the control method for the DC uninterruptible power supply 100 are capable of converting AC power into DC power by the PWM converter 11 and suppressing load fluctuations to the external load 200 during bypass switching operation. can be provided.

Furthermore, in the present embodiment, as described above, the control unit 30 controls the buck-boost unit 12 to lower the voltage of the output voltage V _DC than the voltage of the output voltage V _Byp during the bypass power supply switching operation. I do. As a result, during the bypass power supply switching operation, the control unit 30 controls the buck-boost unit 12 to change the output voltage V _DC , which is the output voltage from the buck-boost unit 12, to the output voltage V _Byp , which is the output voltage from the bypass unit 20. can be lower than. As a result, during the bypass power supply switching operation, the current value I _DC of the output current from the buck-boost section 12 can be decreased, and the current value I _Byp of the output current from the bypass section 20 can be increased.

Further, in the present embodiment, as described above, during the bypass power supply switching operation, the control unit _{30 calculates} the difference ( Control is performed to change the current value I _Byp and the current value I _DC by lowering the output voltage V _DC by the step-up/down unit 12 based on the current value I _Byp ). Thereby, during the bypass power supply switching operation, the current value I Byp, which is the current value of the output current from the bypass section 20, can _be obtained from the difference between the current value I _DC and the current value I _OUT . As a result, by lowering the output voltage V _DC , which is the output voltage from the buck-boost section 12, based on the current value I _Byp and the current value I _DC , the power converter 10 (buck-boost section 12) can easily It is possible to gradually shift the share of the current amount from the output of the bypass section 20 to the output of the bypass section 20.

Furthermore, in the present embodiment, as described above, the DC uninterruptible power supply 100 is configured to operate the buck-boost section 12 and the bypass section 20 when the current value I _DC becomes equal to or less than a predetermined current value during the bypass power supply switching operation. It is configured to disconnect electrically from the As a result, during the bypass power supply switching operation, the current value I _DC , which is the current value of the output current from the buck-boost section 12, is sufficiently reduced, and the current amount to be shared by the load 200 outside the device is shared by the buck-boost section 12. In a state where the output has sufficiently shifted to the output of the bypass section 20, the output to the load 200 outside the device can be switched from the output of the step-up/down section 12 to the output of the bypass section 20. As a result, load fluctuations in the load 200 outside the device during the bypass power supply switching operation can be further suppressed.

Further, in this embodiment, as described above, after the bypass power supply switching operation, the DC uninterruptible power supply 100 electrically connects the current path between the PWM converter 11 and the AC power supply 201 external to the device to 40. As a result, after the bypass power supply switching operation in which power is discharged from the battery 40, charging of the battery 40 is started, so that after the bypass power supply switching operation, the output to the load 200 outside the device is changed from the output of the bypass section 20 to the power supply. When performing the power conversion section power supply switching operation of switching to the output of the conversion section 10, it is possible to prevent the power charged in the battery 40 from running out.

Further, in the present embodiment, as described above, the control unit 30 controls the buck-boost unit 12 to boost the voltage of the output voltage V _DC more than the voltage of the output voltage V _Byp during the power conversion unit feeding switching operation. control. As a result, during the power conversion unit power supply switching operation, the control unit 30 controls the buck-boost unit 12 to change the output voltage V _DC , which is the output voltage from the buck-boost unit 12, to the output voltage, which is the output voltage from the bypass unit 20. It can be higher than V _Byp . As a result, during the bypass power supply switching operation, the current value I _DC of the output current from the buck-boost section 12 can be increased, and the current value I _Byp of the output current from the bypass section 20 can be decreased.

Furthermore, in the present embodiment, as described above, the control unit 30 controls the step-up/down step based on the difference between the current value I _DC and the current value I _OUT (current value I _Byp ) during the power conversion section power supply switching operation. By boosting the output voltage V _DC by the unit 12, control is performed to change the current value I _Byp and the current value I _DC . As a result, during the power conversion unit feeding switching operation, the current value I Byp, which is the current value of the output current from the bypass unit 20, can be obtained from the difference between the current value I _DC and the _current value I _OUT . As a result, by boosting the output voltage I DC, which is the output voltage from the buck-boost section 12, based on the current value I _Byp and _{the current value I DC ,} it is possible to easily convert the output of the bypass section 20 to the power conversion section 10. It is possible to gradually shift the share of the current amount to the output of the step-up/boost unit 12 (increase the share of the current amount of the output from the power conversion unit 10).

In addition, in this embodiment, as described above, the DC uninterruptible power supply 100 connects the buck-boost section 12 and the bypass when the current value I _Byp becomes equal to or less than a predetermined current value during the power conversion section power supply switching operation. The electrical connection with the section 20 is disconnected. As a result, during the power conversion section power supply switching operation, the current value I _Byp , which is the current value of the output current from the bypass section 20, is sufficiently reduced, and the current amount to be shared by the load 200 outside the device is shared by the bypass section 20. In a state where the output has sufficiently shifted to the output of the step-up/down section 12, the output to the load 200 outside the device can be switched from the output of the bypass section 20 to the output of the step-up/down section 12. As a result, it is possible to further suppress load fluctuations to the load 200 external to the device during the power converter feeding switching operation.

Further, in this embodiment, as described above, the buck-boost section 12 is a chopper type converter that boosts or steps down the DC power output from the battery 40 and outputs the voltage, and the control section 30 controls the PWM converter during the switching operation. In a state where the current path between the converter 11 and the AC power supply 201 outside the device is electrically separated, the buck-boost section 12 (chopper type converter) is controlled to increase the output voltage, which is the output voltage from the buck-boost section 12. Performs control to change V _DC . This allows the power from the battery 40 to be stepped up or down more efficiently than when the power from the battery 40 is converted into an isolated DC voltage using a flyback method or the like.

[Modified example]
The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is indicated by the claims rather than the description of the above embodiments, and further includes all changes (modifications) within the meaning and scope equivalent to the claims.

For example, in the above embodiment, the control unit 30 controls the current value I _Byp (first current value) that is the current value of the output current from the bypass unit 20 and the output voltage V _Byp (first current value) that is the output voltage from the bypass unit 20. Although an example has been shown in which control is performed to change the output voltage V _DC (second output voltage) based on the second output voltage), the present invention is not limited to this. For example, the control unit may perform control to change the second output voltage based only on either the first output voltage or the first output current.

In the above embodiment, the control unit 30 also controls the current value I _Byp (first current value) which is the current value of the output current from the bypass unit 20 and the output voltage which is the output voltage from the bypass unit 20 during the switching operation. Although an example of acquiring V _Byp (first output voltage) has been shown, the present invention is not limited to this. In the present invention, the control unit may acquire only one of the first current value and the first output voltage.

In the above embodiment, the control unit 30 controls the current value I _DC (second current value), which is the current value of the output current from the buck-boost unit 12, and the current value I _OUT (third current value) during the bypass power supply switching operation. control to change the current value I _Byp (first current value) and the current value I _DC (second current value) by lowering the output voltage V _DC by the buck-boost unit 12 based on the difference between the current value and the current value) Although an example is shown in which this is performed, the present invention is not limited to this. In the present invention, the control section changes the first current value and the second current value by stepping down the second output voltage using the buck-boost section 12 based on the first output voltage during the bypass power supply switching operation. Control may also be performed.

Further, in the embodiment described above, after the bypass power supply switching operation, the DC uninterruptible power supply 100 electrically connects the current path between the PWM converter 11 and the AC power supply 201 external to the device to charge the battery 40. Although an example is shown in which the system is configured to start, the present invention is not limited thereto. In the present invention, the DC uninterruptible power supply device may be configured to start charging the battery 40 before the power conversion section power supply switching operation.

Further, in the embodiment described above, the control unit 30 performs the lifting/lowering operation based on the difference between the current value I _DC (second current value) and the current value I _OUT (third current value) during the power conversion unit power feeding switching operation. An example is shown in which control is performed to change the current value I _Byp (first current value) and the current value I _DC (second current value) by boosting the output voltage V _DC (second output voltage) by the pressure section 12. However, the present invention is not limited to this. In the present invention, the control section increases the first current value and the second current value by boosting the second output voltage using the buck-boost section 12 based on the first output voltage during the power conversion section feeding switching operation. You may perform control to change it.

Furthermore, in the embodiment described above, the buck-boost section 12 is a chopper type converter, but the present invention is not limited to this. In the present invention, the step-up/down section may be configured to convert power from a battery into an isolated DC voltage using a flyback method or the like.

Further, in the above embodiment, an example was shown in which one DC uninterruptible power supply 100 outputs (supplies) power to a load outside the device, but the present invention is not limited to this. The present invention may be applied to a plurality of DC uninterruptible power supplies that are electrically arranged in parallel with respect to a load outside the device.

In addition, in the above embodiment, for convenience of explanation, the control processing at the time of the bypass power supply switching operation of the control unit 30 of the present invention and the power conversion section power supply switching operation is performed in order according to the processing flow. Although the description has been made using a flowchart, the present invention is not limited thereto. In the present invention, the processing operation by the control unit may be performed by event-driven processing that executes processing on an event-by-event basis. In this case, it may be completely event-driven, or it may be a combination of event-driven and flow-driven.

10 Power conversion unit 11 PWM converter 12 Buck-boost unit 20 Bypass unit 21 Bypass rectifier 30 Control unit 40 Battery 100 DC uninterruptible power supply I _Byp current value (first current value)
I _DC current value (second current value)
I _OUT current value (third current value)
V _Byp output voltage (1st output voltage)
V _DC output voltage (second output voltage)

Claims (11)

A PWM converter that converts AC power input from outside the device into DC power by PWM control and outputs the DC power, and a PWM converter that steps up or steps down the DC power output from the battery and outputs it, and the output side is connected to the output side of the PWM converter. a power conversion section including a buck-boost section connected;
a bypass section that is connected to the output side of the power conversion section and includes a bypass rectifier that converts AC power input from outside the device into DC power and outputs the DC power;
Bypass power supply switching operation of switching the output to a load external to the device from the output of the power conversion section to the output of the bypass section, or the power switching operation of switching the output to the load external to the device from the output of the bypass section to the output of the power conversion section At least one of a first current value that is the current value of the output current from the bypass section or a first output voltage that is the output voltage from the bypass section during at least one of the switching operations of the converter power supply switching operation. a control section configured to perform control to change a second output voltage, which is the output voltage from the step-up/down section, based on the step-up/down section. The control unit is configured to control the step-up/down unit to lower the voltage of the second output voltage than the voltage of the first output voltage during the bypass power supply switching operation. The DC uninterruptible power supply according to claim 1. The control section is configured to control, during the bypass power supply switching operation, a second current value that is a current value of an output current from the buck-boost section, and a third current value that is a total value of the first current value and the second current value. The step-up/down section is configured to perform control to change the first current value and the second current value by stepping down the second output voltage by the step-up/down section based on a difference between the first current value and the second current value. The DC uninterruptible power supply device according to item 2. 3 . The step-up/down section and the bypass section are electrically disconnected from each other when the second current value becomes equal to or less than a predetermined current value during the bypass power supply switching operation. DC uninterruptible power supply described in . 5. The device according to claim 4, wherein the device is configured to electrically connect a current path between the PWM converter and an AC power source external to the device to start charging the battery after the bypass power supply switching operation. DC uninterruptible power supply. The control unit is configured to control the step-up/down unit to increase the voltage of the second output voltage more than the voltage of the first output voltage when switching the power supply to the power conversion unit. The DC uninterruptible power supply according to claim 5. The control section is configured to increase the second output voltage by the step-up/down section based on the difference between the second current value and the third current value during the power conversion section power supply switching operation. The DC uninterruptible power supply according to claim 6, configured to perform control to change the first current value and the second current value. The present invention is configured to disconnect electrical connection between the step-up/down section and the bypass section when the first current value becomes equal to or less than a predetermined current value during the power conversion section power supply switching operation. The DC uninterruptible power supply device according to item 7. The buck-boost section is a chopper converter that boosts or steps down the DC power output from the battery and outputs the voltage.
During the switching operation, the control unit controls the chopper type converter in a state in which a current path between the PWM converter and an AC power source external to the device is electrically disconnected, and outputs an output from the chopper type converter. The DC uninterruptible power supply device according to claim 1, wherein the DC uninterruptible power supply device is configured to perform control to change the second output voltage. A buck-boost unit that steps up or steps down the DC power output from the battery and outputs the voltage; and a bypass that is connected to the output side of the buck-boost unit and converts the AC power from the AC power source outside the device into DC power and outputs the DC power. A control method for a DC uninterruptible power supply device that outputs DC power to the outside of the device, the method comprising:
acquiring a first current value that is the current value of the output current from the bypass section or a first output voltage that is the output voltage of the bypass section;
a step of changing a second output voltage that is an output voltage from the buck-boost section based on at least one of the acquired first current value or first output voltage; control method. The buck-boost section is a chopper converter that boosts or steps down the DC power output from the battery and outputs the voltage.
11. The method for controlling a DC uninterruptible power supply according to claim 10, wherein the step of changing the second output voltage is a step of changing the second output voltage that is the output voltage from the chopper type converter.

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