Power supply device

Abstract

The present invention comprises: a power generation unit 10 that has a power output unit 1 for outputting direct-current power, which is based on normal power generated by a normal power supply, and that has a storage battery 2 which is provided in parallel to the power output unit 1 and which stores charge power charged by the direct-current power, the power generation unit generating output power that includes the direct-current power and the charge power; a power supply unit 4 that supplies the output power to a load; a switching unit that is provided between the power generation unit 10 and the power supply unit 4, and switches between a state in which the output power is supplied to the power supply unit 4 and a state in which the output power is not supplied; and a control unit 9 that controls the state of the switching unit to cause the same to switch between a first state in which the storage battery is charged by the direct-current power without supplying the output power to the load, and a second state in which the power supply unit 4 can supply the output power to the load.

Description

power supply device

[0001] The present invention relates to a power supply device that supplies power to a load.

[0002] BACKGROUND ART Power supply devices such as uninterruptible power supplies supply power to a load from an on-board storage battery when a power outage or other reason makes it difficult for a normal power source to supply power to the load (see, for example, Patent Document 1).

[0003] Japanese Patent Application Laid-Open No. 2020-54020

[0004] A load may require more power than the utility power supply can supply. The technology described in Patent Document 1 has a problem in that it is not possible to supply more power to the load than the utility power supply can supply.

[0005] The present invention has been made in consideration of these points, and has as its object to provide a power supply device that can supply a load with more power than can be supplied by a normal power source.

[0006] A first aspect of the power supply device of the present invention includes a power output unit that outputs DC power based on normal power generated by a normal power source, and a storage battery that is arranged in parallel with the power output unit and stores charging power charged with the DC power, and is further equipped with a power generation unit that generates output power including the DC power and the charging power, a power supply unit that supplies the output power to a load, a switching unit that is arranged between the power generation unit and the power supply unit and switches between a state in which the output power is supplied to the power supply unit and a state in which the output power is not supplied, and a control unit that controls the state of the switching unit to switch between a first state in which the storage battery is charged with the DC power without supplying the output power to the load, and a second state in which the power supply unit can supply the output power to the load.

[0007] The power supply device may further include a voltage detection unit that detects a battery voltage of the storage battery, and the control unit may set the power supply device to the first state by switching the switching unit to a state where the output power is not supplied to the power supply unit while the battery voltage is less than a first voltage, and may switch the power supply device from the first state to the second state by switching the switching unit to a state where the output power is supplied to the power supply unit in response to a change in the battery voltage from less than the first voltage to equal to or greater than the first voltage.

[0008] The control unit may switch the power supply device from the second state to the first state by switching the switching unit to a state in which the output power is not supplied to the power supply unit when the battery voltage changes from a second voltage or higher that is lower than the first voltage to a voltage lower than the second voltage.

[0009] When the power supply device is in the second state, the power output unit may change the DC power in accordance with the state of the load while the DC power to be output is below a predetermined threshold, and when the DC power to be output reaches the threshold, the power output unit may not increase the DC power regardless of the state of the load.

[0010] When the power supply device is in the second state, the power output unit may increase the DC power by increasing a duty ratio of pulse width modulation as the power consumption of the load increases, while the DC power to be output is less than the threshold value.

[0011] The storage battery may output the charging power when the power to be supplied to the load by the power supply unit is greater than the threshold. The storage battery may output the charging power while a relationship between an input impedance of the power supply unit and an input impedance of the storage battery satisfies a condition under which the DC power is not supplied to the storage battery. The storage battery may output the charging power after the input impedance of the power supply unit becomes equal to or less than the input impedance of the storage battery.

[0012] The storage battery may be charged based on the DC power while the relationship between the input impedance of the power supply unit and the input impedance of the storage battery satisfies the condition for the DC power output by the power output unit to be supplied to the storage battery.

[0013] The power supply unit may supply the output power to the load via an output terminal, and the control unit may control the power supply unit and the switching unit to store the supplied power in the storage battery when the control unit is set to a mode in which power is supplied from a battery of an electric vehicle connected to the output terminal.

[0014] When the control unit is set to a mode in which power is supplied to an electric power supplier, the control unit may control the power supply unit and the switching unit to return the power stored in the storage battery to the electric power supplier from the input terminal side.

[0015] The present invention has the effect of being able to supply a load with power greater than the power that can be supplied from a utility power source.

[0016] It is a figure which shows the outline of the power supply device of embodiment. It is a figure for demonstrating the change of the operation state of the power supply device. It is a flowchart which shows the processing procedure of the power supply device supplying the power to the load. It is a figure which shows the configuration of the power supply device of modification.

[0017] [Outline of Power Supply Device 100] Fig. 1 is a diagram showing an outline of the power supply device 100 of this embodiment. The power supply device 100 is supplied with normal power from a normal power source (not shown). The normal power source is, for example, a commercial AC power source. The normal power source is not limited to a commercial AC power source as long as it is a device that generates power, and may be an industrial power source, a solar power generation device, a power generation device using hydrogen fuel or fossil fuel, or a storage battery.

[0018] The power supply device 100 supplies power to a load based on normal power supplied from a normal power source. The power supply device 100 operates as an uninterruptible power supply. When the supply of normal power from the normal power source is stopped, the power supply device 100 supplies output power from the built-in storage battery 2 to the load. The storage battery 2 stores normal power and discharges the stored charged power when the supply of normal power is stopped. When the power supply device 100 is connected to a load that requires more power than the normal power that the normal power source can supply, the power supply device 100 supplies the charged power stored in the built-in storage battery 2 to the load in addition to the power from the normal power source.

[0019] In this way, the power supply device 100 can supply to a load a power greater than the normal power that can be supplied from a normal power source. For example, the power supply device 100 can rapidly charge an EV (Electric Vehicle) or simultaneously charge multiple smartphones during a disaster. The power supply device 100 includes a power output unit 1, a storage battery 2, a first relay 3, a power supply unit 4, a second relay 5, a relay control unit 6, a relay control unit 7, a voltage detection unit 8, and a control unit 9.

[0020] The power output unit 1 outputs DC power based on the normal power generated by the normal power supply. For example, the power output unit 1 is a DC / AC inverter that converts AC power supplied from the normal power supply via an input terminal 11 into DC power. When DC normal power is supplied from the normal power supply, the power output unit 1 may be a DC / DC converter that converts the supplied DC normal power. The DC power P supplied by the power output unit 1 １ This is indicated by a thick arrow in FIG.

[0021] The power output unit 1 operates based on control data input from the control unit 9. When the power output unit 1 detects that the supply of normal power from the normal power source to the power output unit 1 has started, the power output unit 1 may input information indicating that the supply of normal power has started to the control unit 9. When the power output unit 1 detects that the supply of normal power from the normal power source to the power output unit 1 has stopped, the power output unit 1 may input information indicating that the supply of normal power has stopped to the control unit 9.

[0022] In the example of Fig. 1, the power output unit 1 has a PWM control circuit that changes the duty in accordance with the magnitude of the load using, for example, a PWM (Pulse Width Modulation) method. The power output unit 1 outputs a DC voltage obtained by smoothing the voltage generated by the PWM control circuit and a DC power P corresponding to the DC current. １ The power output unit 1 outputs DC power P １ is output to the storage battery 2 or the power supply unit 4.

[0023] The power output unit 1 outputs the generated DC power P １ In the first state, the DC power P １ The power output unit 1 charges the storage battery 2 with DC power P １ DC power P output when the load is in the second state where it can be supplied to the load. １ While the DC power P １ The threshold value is, for example, a value smaller than the normal power supplied to the power output unit 1.

[0024] For example, the power output unit 1 increases the DC power P １ At this time, the power output unit 1 increases the duty ratio of the PWM to increase the DC power P １ The power output unit 1 has a limiter for preventing the output of power above a preset threshold, and the DC power P １ When the threshold value is reached, the DC power P １ The threshold value is, for example, the DC power P that the power output unit 1 can output. １ It is determined based on the maximum value of

[0025] The first relay 3 is provided between the power output unit 1 and the storage battery 2. The first relay 3 switches between a state in which the power output unit 1 and the storage battery 2 are connected and a state in which the power output unit 1 and the storage battery 2 are not connected, based on a control signal output by a relay control unit 6. That is, the first relay 3 switches between a state in which the power output unit 1 and the storage battery 2 are connected and a state in which the power output unit 1 and the storage battery 2 are not connected, based on a control signal output by a relay control unit 6. １to the storage battery 2 or the power supply unit 4, and the DC power P １ Switching between an on state and an off state.

[0026] The storage battery 2 is, for example, a lithium ion battery, a lithium titanate battery, an all-solid-state battery, or the like. The storage battery 2 is provided in parallel with the power output unit 1. The storage battery 2 includes, for example, a plurality of storage battery modules connected in series. The storage battery 2 outputs DC power P １ The storage battery 2 stores the charging power stored by the power supply unit 4. The storage battery 2 supplies the stored charging power to the load via the power supply unit 4. The charging power P ２ This is indicated by a thick arrow in FIG.

[0027] As shown by the rectangular dashed line in Fig. 1, the power output unit 1, the storage battery 2, and the first relay 3 constitute a power generation unit 10. The power generation unit 10 generates the DC power P １ and the charging power P stored in the storage battery 2. ２ Output power P ３ Output power P ３ This is indicated by a thick arrow in FIG.

[0028] The power supply unit 4 receives the output power P generated by the power generation unit 10. ３ The power supply unit 4 supplies the output power P ３ to the load. For example, the power supply unit 4 is a DC / AC inverter that converts the output power generated by the power generation unit 10 into AC power. The power supply unit 4 may also be a DC / DC converter that converts the output power generated by the power generation unit 10 into DC power.

[0029] When the first relay 3 and the second relay 5 are both in the ON state, the storage battery 2 receives the DC power P １ and supplies charging power P ２ More specifically, the storage battery 2 outputs the DC power P １ While the condition for supplying DC power P to the storage battery 2 is satisfied,１ Specifically, when the input impedance of the power supply unit 4 is greater than the input impedance of the storage battery 2, or while the second relay 5 is in the OFF state, the DC power P １ Charge based on.

[0030] On the other hand, the storage battery 2 has a relationship between the input impedance of the power supply unit 4 and the input impedance of the storage battery 2, and the relationship between the input impedance of the power supply unit 4 and the input impedance of the storage battery 2 is １ While the condition that the charging power P is not supplied to the storage battery 2 is satisfied, ２ It outputs DC power P １ The condition under which the power is not supplied to the storage battery 2 is, for example, that the input impedance of the power supply unit 4 is equal to or lower than the input impedance of the storage battery 2 .

[0031] The storage battery 2 is charged with power P ２ When the load is not being discharged, the power to be supplied to the load increases, and the DC power P １ When the threshold value is reached, the DC power P １ When the charging power P reaches the threshold value, the output impedance of the power output unit 1 becomes larger than the output impedance of the storage battery 2. As a result, the storage battery 2 receives the charging power P ２ In this way, the storage battery 2 starts outputting the maximum DC power P that the power supply unit 4 can output to the load. １ When the DC power P １ The shortage of charging power P ２ This can be compensated for by:

[0032] The second relay 5 is provided between the power generating unit 10 and the power supply unit 4. The second relay 5 is connected to the power supply unit 4. The second relay 5 is connected to the power supply unit 4. The second relay 5 is connected to the power supply unit 4. ３ to the power supply unit 4, and the output power P ３ The second relay 5 operates as a switching unit for switching between an ON state and an OFF state in which no power is supplied to the power supply unit 4. The second relay 5 switches between an ON state and an OFF state based on a control signal output by the relay control unit 7.

[0033] The relay control unit 6 controls the first relay 3. The relay control unit 6 switches the first relay 3 between an on state and an off state based on control information generated by the control unit 9. The relay control unit 7 controls the second relay 5. The relay control unit 7 switches the second relay 5 between an on state and an off state based on control information generated by the control unit 9. The relay control units 6 and 7 may be included in the control unit 9.

[0034] The voltage detection unit 8 detects the voltage (hereinafter referred to as “battery voltage”) output by the storage battery 2. The voltage detection unit 8 inputs information indicating the detected battery voltage to the control unit 9.

[0035] The control unit 9 is, for example, a CPU (Central Processing Unit). The control unit 9 controls the operating states of the power output unit 1, the first relay 3, and the second relay 5. The control unit 9 also identifies the battery voltage based on information indicating the battery voltage input from the voltage detection unit 8. The control unit 9 controls the operating state of the power supply unit 4. If the load connected to the output terminal 12 is a robot that repeatedly charges and discharges according to a predetermined schedule, the control unit 9 can predict the power required by the load. In this way, if the control unit 9 can predict the power required by the load connected to the output terminal 12, it determines the output power P required by the power supply unit 4 when supplying the predicted power to the load. ３ The value obtained by adding a predetermined margin to this is the output power P ３ The control unit 9 calculates the output power P to be supplied to the power supply unit 4 so as not to exceed this upper limit value. ３ In this way, the control unit 9 may limit the second voltage V ｔｈ２ The output power P ３ can be limited.

[0036] [Changes in Operational State of Power Supply Device 100] The power supply device 100 has a plurality of operational states that change depending on the state of charge of the storage battery 2, the magnitude of the load, etc. The control unit 9 changes the operational state by controlling the first relay 3 and the second relay 5 via the relay control unit 6 and the relay control unit 7.

[0037] The control unit 9 switches the first relay 3 between an on state and an off state via the relay control unit 6. The control unit 9 switches the second relay 5 between an on state and an off state via the relay control unit 7. The control unit 9 controls the state of the second relay 5 to thereby control the output power P generated by the power generation unit 10. ３ DC power P ２ a first state in which the storage battery is charged by the power supply unit 4; and a second state in which the power supply unit 4 outputs power P ３ and a second state in which the power supply can be supplied to the load.

[0038] In the example of this specification, the control unit 9 switches between the first state and the second state based on the battery voltage of the storage battery 2 detected by the voltage detection unit 8. More specifically, the control unit 9 switches between the first state and the second state based on the battery voltage of the storage battery 2 detected by the voltage detection unit 8. ｔｈ１ While the output power P ３ The control unit 9 sets the power supply device 100 to the first state by switching the second relay 5 (corresponding to the switching unit) to a state where the battery voltage of the storage battery 2 is not supplied to the power supply unit 4. ｔｈ１ less than the first voltage V ｔｈ１ In response to the above changes, the output power P generated by the power generating unit 10 ３ to the power supply unit 4, the power supply device 100 is switched from the first state to the second state.

[0039] 2A and 2B are diagrams for explaining changes in the operating state of the power supply device 100. FIG. 2A shows the output power P generated by the power generating unit 10. ３ 2(b) shows the change in the charging power P output from the storage battery 2. ２ In FIG. 2B, the area where a positive value is shown is the area where the storage battery 2 is charging the power P ２ 2(b), the area where negative values ​​are shown indicates the state where the storage battery 2 is being charged.

[0040] FIG. 2(c) shows the DC power P supplied by the power output unit 1. １2(d) shows the change in the battery voltage of the storage battery 2. FIG. 2(e) shows the change in the state of the first relay 3. FIG. 2(f) shows the change in the state of the second relay 5.

[0041] The vertical axes of the graphs in Figures 2(a) to 2(c) represent power, the vertical axis of the graph in Figure 2(d) represents voltage, and the vertical axes of the graphs in Figures 2(e) and 2(f) represent the on / off states of the first relay 3 or the second relay 5. The horizontal axis represents time.

[0042] In the stopped state, no normal power is supplied from the normal power source to the power output unit 1. In the stopped state, the first relay 3 and the second relay 5 are in the OFF state. In the stopped state, the power output unit 1 is not connected to either the storage battery 2 or the power supply unit 4, and therefore, DC power P １ As shown in the graph of the stopped state in FIG. 2(c), １ = 0 W. Since the storage battery 2 is not connected to the power supply unit 4, the charging power P ２ As shown in FIG. 2(b), P ２ = 0W.

[0043] When the control unit 9 acquires information from the power output unit 1 indicating that supply of normal power from the normal power source to the power output unit 1 has started in the stopped state, the control unit 9 instructs the relay control unit 6 to switch the first relay 3 to the on state. When the first relay 3 is switched to the on state, the power supply device 100 enters the first state.

[0044] In the first state, the first relay 3 is in the ON state as shown in Fig. 2(e), and the second relay 5 is in the OFF state as shown in Fig. 2(f). In the first state, the DC power P １ is the output power P ３ It is not supplied as P ３ = 0 W (FIG. 2(a)). The control unit 9 calculates this DC power P １ As shown in the graph of the first state in FIG. 2(b), the charging power P ２ indicates a negative value. At this time, the battery voltage of the storage battery 2 gradually increases (FIG. 2(d)).

[0045] When the output power that the power supply unit 4 should supply to the load is greater than the threshold, the storage battery 2 ２ While the control unit 9 is charging the storage battery 2 in the first state, the battery voltage of the storage battery 2 gradually increases. ｔｈ１ When this occurs, the second relay 5 is switched from the OFF state to the ON state. When the second relay 5 is switched to the ON state, the power supply device 100 transitions from the first state to the second state. In the second state, the first relay 3 continues to be in the ON state, as shown in FIG. 2( e).

[0046] In the second state, the charging power P ２ Mode A: The charging power P ２ 2 shows an example in which the power supply device 100 transitions from mode A to mode B in the second state once, but the power supply device 100 may transition between mode A and mode B multiple times in the second state.

[0047] The output power P that the power supply unit 4 should supply to the load ３ is equal to or less than the threshold value, the power supply device 100 operates in mode A. In mode A, as shown in FIG. 2(b), the charging power P ２ = 0W.

[0048] The output power P that the power supply unit 4 should supply to the load ３ is greater than the threshold, the power supply device 100 operates in mode B. In mode B, the output impedance of the power output unit 1 becomes greater than the output impedance of the storage battery 2. Therefore, the charging power P ２ starts to be output, and charging power P ２ At this time, the output power P ３ is the DC power P １ and charging power P ２ and (P ３ =P １ +P ２ ).

[0049] In mode B, the charging power P supplied from the storage battery 2 to the power supply unit 4 ２ 2(d), the battery voltage of the storage battery 2 gradually decreases. The control unit 9 detects whether the battery voltage of the storage battery 2 detected by the voltage detection unit 8 is equal to or lower than the second voltage V ｔｈ２ It is determined whether the second voltage V ｔｈ２ is the first voltage V ｔｈ１ The second voltage V ｔｈ２ is determined, for example, according to the remaining battery capacity of the storage battery 2 required for the power supply device 100 to operate in the event of an emergency shutdown of the normal power supply.

[0050] The control unit 9 determines whether the battery voltage of the storage battery 2 is a second voltage V ｔｈ２ From the above, the second voltage V ｔｈ２ When the output power P ３ The power supply device 100 is switched from the second state to the first state by switching the second relay 5 to a state where the DC power P is not supplied to the power supply unit 4. In this first state, as described above, the DC power P １ After that, the power supply device 100 switches to the second state, and when the power to be supplied to the load increases, the DC power P １ and charging power P ２ Output power P ３ is supplied to the load in mode B.

[0051] 3 is a flowchart showing the processing procedure for supplying power to a load by the power supply device 100. For example, this processing procedure starts when the power output unit 1 detects that the supply of normal power from the normal power source to the power output unit 1 has started, and the power output unit 1 inputs information indicating that the supply of normal power has started to the control unit 9.

[0052] First, the control unit 9 instructs the relay control unit 6 to switch the first relay 3 from the OFF state to the ON state (S101). ｔｈ１ The control unit 9 determines whether the battery voltage of the storage battery 2 is equal to or greater than the first voltage V ｔｈ１If it is determined that the battery voltage of the storage battery 2 is equal to or greater than the second voltage V (YES in S102), the control unit 9 instructs the relay control unit 7 to switch the second relay 5 from the OFF state to the ON state (S103). ｔｈ２ It is determined whether or not the value is equal to or less than the above (S104).

[0053] The control unit 9 determines whether the battery voltage of the storage battery 2 is a second voltage V ｔｈ２ If the control unit 9 determines that the normal power supply voltage Vdc is equal to or lower than the normal power supply voltage Vdc (YES in S104), it instructs the relay control unit 7 to switch the second relay 5 from the ON state to the OFF state (S105). The control unit 9 determines whether the power output unit 1 has detected that the supply of normal power from the normal power supply has been stopped (S106). If the power output unit 1 has detected that the supply of normal power has been stopped (YES in S106), the control unit 9 instructs the relay control unit 6 to switch the first relay 3 from the ON state to the OFF state (S107), and ends the process.

[0054] The control unit 9 determines in step S102 that the battery voltage of the storage battery 2 is equal to or higher than the first voltage V ｔｈ１ If it is determined that the battery voltage of the storage battery 2 is less than the second voltage V (NO in S102), the control unit 9 repeats the determination in S102. ｔｈ２ If the control unit 9 determines that the normal power supply is stopped (NO in S104), the control unit 9 repeats the determination in S104. If the control unit 9 determines in S106 that the power output unit 1 has not detected that the normal power supply has stopped (NO in S106), the control unit 9 returns to the process in S102.

[0055] [First Modification] In the present embodiment, an example has been described in which the power supply device 100 includes the first relay 3 and the second relay 5. However, the present invention is not limited to the example in which the power supply device 100 includes two relays. For example, the power supply device 100 may include only one relay.

[0056] Fig. 4 is a diagram showing the configuration of a power supply device 100 of this modified example. In the example of Fig. 4, the power supply device 100 differs from the power supply device 100 shown in Fig. 1 in that it does not include either the first relay 3 or the relay control unit 6 corresponding to the first relay. In the power supply device 100 shown in Fig. 4, the circuit elements other than the first relay and the relay control unit 6 are the same as those in Fig. 1.

[0057] [Second Modification] The user may be able to set the control unit 9 to transition to a power receiving mode in which the control unit 9 receives a supply of power from the battery of the EV connected to the output terminal 12. In this power receiving mode, when the user purchases power from the EV, the control unit 9 controls the power output unit 1 and the power supply unit 4 to receive a supply of power from the battery of the EV connected to the output terminal 12.

[0058] In the power receiving mode, the control unit 9 controls the power supply unit 4 and the relay control unit 6 to store the received power in the storage battery 2. The control unit 9 may transition to a supply mode in which the control unit 9 supplies power to an electric utility company for the purpose of selling the power to the electric utility company. When the control unit 9 is set to the supply mode, the control unit 9 may control the power supply unit 4 and the relay control unit 7 to return the power stored in the storage battery 2 from the input terminal 11 side. In this way, the power supply device 100 can exchange power bidirectionally.

[0059] [Effects of the Power Supply Device 100] In the power supply device 100 of this embodiment, the power supply unit 4 supplies to the load output power including DC power based on the normal power supplied from the normal power source and charging power from the storage battery 2. Therefore, the power supply unit 4 can supply to the load power greater than the normal power itself.

[0060] The present invention has been described above using embodiments, but the technical scope of the present invention is not limited to the scope described in the above embodiments, and various modifications and changes are possible within the scope of the gist of the present invention. For example, all or part of the device can be configured by functionally or physically distributing or integrating in any unit. Furthermore, new embodiments resulting from any combination of multiple embodiments are also included in the embodiments of the present invention. The effects of the new embodiments resulting from the combination also have the effects of the original embodiments.

[0061] REFERENCE SIGNS LIST 1 Power output unit 2 Storage battery 3 First relay 4 Power supply unit 5 Second relay 6 Relay control unit 7 Relay control unit 8 Voltage detection unit 9 Control unit 10 Power generation unit 100 Power supply device

Claims

1. a power generating unit including a power output unit that outputs DC power based on normal power generated by a normal power source, and a storage battery that is provided in parallel with the power output unit and stores charging power charged by the DC power, and that generates output power including the DC power and the charging power; a power supply unit that supplies the output power to a load; a switching unit that is provided between the power generation unit and the power supply unit and that switches between a state in which the output power is supplied to the power supply unit and a state in which the output power is not supplied; a voltage detection unit for detecting a battery voltage of the storage battery; a control unit that controls a state of the switching unit to switch between a first state in which the storage battery is charged with the DC power without supplying the output power to the load and a second state in which the power supply unit can supply the output power to the load, switches the power supply unit from the first state to the second state by switching the switching unit to a state in which the output power is supplied to the power supply unit in response to a change in the battery voltage from less than a first voltage to equal to or greater than the first voltage, and switches the power supply unit from the second state to the first state by switching the switching unit to a state in which the output power is not supplied to the power supply unit when the battery voltage changes from equal to or greater than a second voltage that is lower than the first voltage to less than the second voltage; A power supply device comprising:

2. a power generating unit including a power output unit that outputs DC power based on normal power generated by a normal power source, and a storage battery that is provided in parallel with the power output unit and stores charging power charged by the DC power, and that generates output power including the DC power and the charging power; a power supply unit that supplies the output power to a load; a switching unit that is provided between the power generation unit and the power supply unit and that switches between a state in which the output power is supplied to the power supply unit and a state in which the output power is not supplied; a control unit that controls a state of the switching unit to switch between a first state in which the storage battery is charged with the DC power without supplying the output power to the load, and a second state in which the power supply unit can supply the output power to the load, predicts in advance an expected output power that is expected to be required by the power supply unit, calculates a value by adding a predetermined value to the predicted output power as an upper limit value of the output power, and limits the output power supplied to the power supply unit so as not to exceed the calculated upper limit value; A power supply device comprising:

3. the control unit switches the switching unit to a state in which the output power is not supplied to the power supply unit while the battery voltage is lower than a first voltage, thereby causing the power supply unit to be in the first state.

2. The power supply device according to claim 1.

4. when the power supply unit is in the second state, the power output unit changes the DC power in accordance with a state of the load while the DC power to be output is less than a predetermined threshold, and when the DC power to be output reaches the threshold, does not increase the DC power regardless of the state of the load.

3. The power supply device according to claim 1 or 2.

5. When the power supply unit is in the second state, while the DC power to be output is less than the threshold, the power output unit increases the DC power by increasing a duty ratio of pulse width modulation as the power consumption of the load increases.

5. The power supply device according to claim 4.

6. The storage battery outputs the charging power when the power to be supplied to the load by the power supply unit is greater than the threshold value.

5. The power supply device according to claim 4.

7. the storage battery outputs the charging power while a relationship between an input impedance of the power supply unit and an input impedance of the storage battery satisfies a condition under which the DC power is not supplied to the storage battery.

7. The power supply device according to claim 6.

8. The storage battery outputs the charging power after the input impedance of the power supply unit becomes equal to or lower than the input impedance of the storage battery.

8. The power supply device according to claim 7.

9. the storage battery is charged based on the DC power while a relationship between an input impedance of the power supply unit and an input impedance of the storage battery satisfies a condition under which the DC power output by the power output unit is supplied to the storage battery.

3. The power supply device according to claim 1 or 2.

10. The power supply unit supplies the output power to the load via an output terminal, the control unit controls the power supply unit and the switching unit to store the supplied power in the storage battery when a mode is set in which power is supplied from a battery of an electric vehicle connected to the output terminal.

3. The power supply device according to claim 1 or 2.

11. When a mode in which power is supplied to an electric power supplier is set, the control unit controls the power supply unit and the switching unit so as to return the power stored in the storage battery to the electric power supplier from the input terminal side.

3. The power supply device according to claim 1 or 2.