Power supply device

Abstract

In a power supply device capable of switching between individual and parallel operation of multiple power supply units, fluctuations in current or voltage during the switching of operating modes are suppressed. [Solution] The system includes a switch that can switch between an ON state in which the output of the first power supply unit and the output of the second power supply unit are connected in parallel, and an OFF state in which they are not connected in parallel. The control unit controls the first power supply unit to have a first drooping characteristic in which the output voltage decreases as the output current of the first power supply unit increases, and controls the second power supply unit to have a second drooping characteristic in which the output voltage decreases as the output current of the second power supply unit increases. When the switch is in the OFF state, the control unit adjusts the first or second drooping characteristic so that the output voltage of the first power supply unit and the output voltage of the second power supply unit match, and then switches the switch to the ON state.

Description

[Technical Field]

[0001] This disclosure relates to a power supply device. [Background technology]

[0002] There is a switching power supply system that operates multiple switching power supplies in parallel. Patent Document 1 discloses a switching power supply system comprising multiple switching power supplies that output DC input from each of multiple power sources to a common output terminal, and multiple droop control circuits that control the duty cycle of the PWM signal in each switching power supply. [Prior art documents] [Patent Documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-22331 [Overview of the Initiative] [Problems that the invention aims to solve]

[0004] Conventionally, when switching the operating mode of multiple switching power supplies between individual operation and parallel operation, there was a problem of current or voltage fluctuations during the switching process.

[0005] This disclosure aims to suppress fluctuations in current or voltage when switching between operating modes in a power supply device that can switch between individual operation and parallel operation of multiple power supply units. [Means for solving the problem]

[0006] The power supply device of the present disclosure includes a first power supply unit and a second power supply unit capable of supplying DC power, a switch that can switch between an ON state in which the output of the first power supply unit and the output of the second power supply unit are connected in parallel and an OFF state in which they are not connected in parallel, and a control unit that controls the first power supply unit, the second power supply unit and the switch. The control unit controls the first power supply unit to have a first drooping characteristic in which the output voltage decreases as the output current of the first power supply unit increases, and controls the second power supply unit to have a second drooping characteristic in which the output voltage decreases as the output current of the second power supply unit increases. The control unit performs a first step of adjusting the first drooping characteristic or the second drooping characteristic so that the output voltage of the first power supply unit and the output voltage of the second power supply unit match when the switch is in the OFF state. After the first step, the control unit performs a second step of switching the switch from the OFF state to the ON state. In this case, by adjusting the drooping characteristics and switching the connection state, fluctuations in current or voltage when switching from individual operation to parallel operation can be suppressed. Here, the control unit performs a third step after the second step, adjusting the first or second drooping characteristic to change the output current of the first power supply unit and the output current of the second power supply unit. In this case, the current supplied to the external device can be shared between the first power supply unit and the second power supply unit in a parallel connection. The system further includes a first connector connected to the first power supply unit and a second connector connected to the second power supply unit. The control unit determines a first range of output voltage for the first connector and a second range of output voltage for the second connector, and in the first step, adjusts at least one of the first droop characteristic and the second droop characteristic based on both the first and second ranges. In this case, the droop characteristics of the power supply units can be adjusted when switching from individual operation to parallel operation so as to appropriately control the output voltage within the range determined for each connector. Furthermore, the control unit performs a fourth step of adjusting the first or second drooping characteristic so that the current flowing through the switch becomes 0 amperes when the switch is in the ON state, and after the first step, performs a fifth step of switching the switch from the ON state to the OFF state. In this case, fluctuations in current or voltage when switching from parallel operation to individual operation can be suppressed. The system further includes a first connector connected to the first power supply unit and a second connector connected to the second power supply unit. The control unit determines a first range of output voltage for the first connector and a second range of output voltage for the second connector. After the fifth step, the control unit adjusts the first droop characteristic based on the first range, or the second droop characteristic based on the second range. In this case, the droop characteristics of the power supply units when switching from parallel operation to individual operation can be adjusted to appropriately control the output voltage within the range determined for each connector. Furthermore, the power supply unit further comprises a converter circuit configured to be connectable to a DC power supply, an inverter circuit configured to be connectable to an AC power supply, and a DC bus connecting the converter circuit and the inverter circuit. The first power supply unit is connected to the DC bus and can supply DC power obtained by converting the DC power of the DC bus, and the second power supply unit is connected to the DC bus and can supply DC power obtained by converting the DC power of the DC bus. In this case, the power supplied from the DC power supply and the AC power supply can suppress fluctuations in current or voltage when switching between individual operation and parallel operation. Furthermore, the power supply device of the present disclosure includes a first power supply unit and a second power supply unit capable of supplying DC power, a switch that can switch between an ON state in which the output of the first power supply unit and the output of the second power supply unit are connected in parallel and an OFF state in which they are not connected in parallel, and a control unit that controls the first power supply unit, the second power supply unit and the switch. The control unit controls the first power supply unit to have a first drooping characteristic in which the output voltage decreases as the output current of the first power supply unit increases, and controls the second power supply unit to have a second drooping characteristic in which the output voltage decreases as the output current of the second power supply unit increases. The control unit adjusts the first drooping characteristic or the second drooping characteristic so that the current flowing through the switch is 0 amperes when the switch is in the ON state, and switches the switch from the ON state to the OFF state. In this case, by adjusting the drooping characteristic and switching the connection state, fluctuations in current or voltage when switching from parallel operation to individual operation can be suppressed. [Brief explanation of the drawing]

[0007] [Figure 1] This diagram shows the configuration of the power supply device according to this embodiment. [Figure 2] This diagram shows a power supply unit whose connection state can be switched. Figure 2(A) shows an example of the power supply unit's configuration, and Figure 2(B) shows an example of the power supply unit and switch state. [Figure 3] This figure shows an example of setting the drooping characteristics. [Figure 4] This figure shows the drooping characteristics and operating point of the power supply unit in the power supply device shown in Figure 2 during individual operation. [Figure 5] This diagram illustrates the adjustment of the drooping characteristics when switching from individual operation to parallel operation. [Figure 6] This diagram illustrates the adjustment of the drooping characteristics after transitioning from individual operation to parallel operation. [Figure 7] This diagram illustrates another example of adjusting the drooping characteristics when switching from individual operation to parallel operation. [Figure 8]This diagram illustrates the adjustment of the drooping characteristics when switching from parallel operation to individual operation. [Figure 9] This diagram shows a power supply unit whose connection state can be switched. Figure 9(A) shows an example of the power supply unit's configuration, and Figure 9(B) shows an example of the power supply unit and switch state. [Figure 10] This figure shows the drooping characteristics and operating points of the power supply units in the power supply device shown in Figure 9 during individual operation. [Figure 11] This diagram illustrates the adjustment of the drooping characteristics when switching from individual operation to parallel operation. [Figure 12] This diagram illustrates the adjustment of the drooping characteristics after transitioning from individual operation to parallel operation. [Figure 13] Figure 13(A) shows the upper limit of the input voltage of external devices during individual and parallel operation, and Figure 13(B) shows the lower limit of the input voltage of external devices during individual and parallel operation. [Figure 14] This diagram shows the configuration for detecting current information inside a power supply unit. [Figure 15] This diagram illustrates the adjustment of the drooping characteristics when switching from parallel operation to individual operation. [Figure 16] This diagram illustrates the adjustment of the drooping characteristics after transitioning from parallel operation to individual operation. [Figure 17] This figure shows another example configuration for detecting information about the internal current of the power supply unit 100. [Figure 18] This figure shows another example of a power supply unit configuration. [Figure 19] This figure shows an example of an application for a power supply unit. [Modes for carrying out the invention]

[0008] The embodiments of this disclosure will be described in detail below with reference to the attached drawings. <Power supply unit configuration> Figure 1 shows the configuration of the power supply unit according to this embodiment. The power supply unit 100 is connected to an AC power supply 300 and a DC power supply 400. The AC power supply 300 is, for example, a grid power supply. The DC power supply 400 is, for example, a solar panel or a storage battery.

[0009] The power supply unit 100 comprises a plurality of power supply units 110, a plurality of connectors 120, a plurality of switches 130, a control unit 150, an AC / DC converter (inverter circuit) 161, and a DC / DC converter (converter circuit) 162. The plurality of power supply units 110, the plurality of connectors 120, and the plurality of switches 130 are individually associated. Although not shown in Figure 1, each set of power supply units 110, connectors 120, and switches 130 is configured to be connected in parallel. The specific configuration for connecting each set in parallel will be described later.

[0010] The power supply unit 100 is connected to the AC power supply 300 via the AC / DC converter 161 and to the DC power supply 400 via the DC / DC converter 162. The power supply unit 110 is also connected to the AC / DC converter 161 and the DC / DC converter 162 via the DC bus 190 and is supplied with DC power from the DC bus 190.

[0011] The power supply unit 110 is equipped with a DC / DC converter 111. The power supply unit 110 converts the supplied DC power using the DC / DC converter 111 and supplies DC power to the connector 120 via the switch 130. The DC / DC converter 111 is implemented, for example, using a step-down chopper circuit or a step-up chopper circuit. The power supply unit 110 is configured to allow changing of the output voltage or output current. The power supply unit 110 is configured to supply DC power to the connector 120 in only one direction. The outputs of the multiple power supply units 110 are electrically isolated from each other.

[0012] Connector 120 connects to an external device acting as a load. The external device can receive power from the power supply unit 100 by connecting to connector 120.

[0013] Switch 130 switches the power supply from the power supply unit 110 to the connector 120 between ON and OFF. By switching the power supply ON / OFF, switch 130 switches between a state in which the outputs of multiple power supply units 110 are connected in parallel (parallel state: an example of the ON state) and a state in which they are not connected in parallel (individual state: an example of the OFF state). Details of how switch 130 switches the connection state of the power supply units 110 will be described later. The ON / OFF switching of switch 130 is controlled by the control unit 150.

[0014] The control unit 150 switches between operating the multiple power supply units 110 in parallel (hereinafter referred to as "parallel operation") or individually (hereinafter referred to as "individual operation") by switching the ON / OFF of the switch 130. The control unit 150 also controls each of the multiple power supply units 110. Specifically, the control unit 150 controls the output voltage and output current of each power supply unit 110. The control unit 150 is implemented, for example, by a memory that stores a program and a processor that executes the program stored in the memory.

[0015] More specifically, the power supply unit 100 includes a voltage sensor (not shown) and a current sensor (not shown). The voltage sensor detects the output voltage v(t) of the power supply unit 110 and sends the detected value to the control unit 150. The current sensor detects the output current of the power supply unit 110 and sends the detected value to the control unit 150. The control unit 150 outputs signals to control the power supply unit 110 and the switch 130.

[0016] More specifically, the control unit 150 controls the power supply unit 110 so that the output voltage decreases as the output current increases. This relationship between the output current and output voltage in the power supply unit 110 is called the droop characteristic. The control unit 150 can adjust the droop characteristic of the power supply unit 110. When switching between parallel operation and individual operation for multiple power supply units 110, the control unit 150 adjusts the droop characteristic of the power supply unit 110 to suppress fluctuations in current or voltage at the output of the power supply unit 110. Details of the droop characteristic of the power supply unit 110 and the method for adjusting the droop characteristic will be described later.

[0017] 〇First Embodiment <Example configuration for enabling switching of connection status> Figure 2 shows a power supply unit 100 whose connection state can be switched. Figure 2(A) shows an example of the configuration of the power supply unit 100. Figure 2(B) shows an example of the state of the power supply unit 110 and the switch 130. For simplicity, the switching of the connection between the two power supply units 110 will be explained.

[0018] In the example shown in Figure 2(A), the two power supply units 110 are distinguished as power supply unit 110A and power supply unit 110B. If there is no need to distinguish between the two power supply units 110A and 110B, they are simply referred to as power supply unit 110. Similarly, the switch 130 corresponding to power supply unit 110A is referred to as switch 130A, and the switch 130 corresponding to power supply unit 110B is referred to as switch 130B. If there is no need to distinguish between the two switches 130A and 130B, they are simply referred to as switch 130.

[0019] Power supply unit 110A is connected to connector 120 via switch 130A. Power supply unit 110B is connected to connector 120 via switch 130B. When connector 201 of external device 210 is connected to connector 120 of power supply unit 100, power is supplied from connector 120 to external device 210.

[0020] The control unit 150 controls the power supply units 110A and 110B and switches 130A and 130B to switch the connection status between the power supply units 110A and 110B and the connector 120, as well as the operating status of the power supply unit 110, for individual operation and parallel operation. In this case, power supply unit 110A is assumed to output power in the case of individual operation.

[0021] As shown in Figure 2(B), in individual operation, power supply unit 110A is in operation and power supply unit 110B is in a stopped state. Switch 130A is ON and switch 130B is OFF. As a result, only the output power of power supply unit 110A is supplied to the external device 210. On the other hand, in parallel operation, both power supply units 110A and 110B are in operation. Switches 130A and 130B are ON. As a result, the output power of both power supply unit 110A and power supply unit 110B is supplied to the external device 210.

[0022] In this example, the output power of power supply unit 110A is supplied to the external device 210 during individual operation, but this is merely an example. Instead of the above example, the output power of power supply unit 110B may be controlled to supply the external device 210 during individual operation. In this case, during individual operation, power supply unit 110A is in a stopped state, power supply unit 110B is in an operating state, switch 130A is OFF, and switch 130B is ON.

[0023] <Switching connection status> Next, the operation of switching the connection state of the power supply unit 110 will be described. Normally, when switching the connection state of the power supply unit 110 from an individual state to a parallel state, or from a parallel state to an individual state, the current or voltage at the output of the power supply unit 110 fluctuates. The control unit 150 suppresses the fluctuation of current or voltage by adjusting the drooping characteristics of the power supply unit 110 when switching the connection state of the power supply unit 110.

[0024] <Method for determining drooping characteristics> When a plurality of power supply units 110 are connected in parallel in the power supply device 100, each power supply unit 110 is provided with an output characteristic (droop characteristic) such that the output voltage decreases as the output current increases, and the current is shared among the plurality of power supply units 110 connected in parallel. The droop characteristic of the power supply unit 110 is set, for example, by controlling the duty ratio of the power supply unit 110.

[0025] FIG. 3 is a diagram showing an example of setting the droop characteristic. In FIG. 3, V o , o hi , , L2 hi , o lo , ,

[0026] , o hi , o lo , , o is the upper limit of the output voltage of the power supply unit 110. V o min is the lower limit of the output voltage of the power supply unit 110. I o max is the upper limit of the output current of the power supply unit 110. These are constants determined by the power supply unit 110. Also, in FIG. 3, V L hi is the upper limit of the input voltage in the external device 210. V L lo is the lower limit of the input voltage in the external device 210. These may be obtained, for example, by communicating between the power supply device 100 and the external device 210, or may be set as predetermined values. When N external devices 210 are connected in parallel to the power supply device 100 for power supply, the information on the upper and lower limits of the output voltage in the k-th (k: 1 ≦ k ≦ N) external device 210 is V Lk hi , V Lk lo , and V L hi = min(V L1 hi , V L2 hi , …, V LN hi ) V L lo = max(V L1 lo , V L2 lo , …, V LN lo ) is set.

[0026] Next, the difference ΔV o hi between the upper limit V o lo of the voltage of the droop characteristic and the lower limit V o of the voltage of the droop characteristic (= V o hi - V o lo ) is determined. An example of a method for determining ΔV o is given below. Here, VL lo <V o max and V L hi >V o min As a first example, a method can be used to determine the value based on the ratio to the input voltage range (upper limit to lower limit) of the external device 210. In this case, ΔV o V o max and V L hi V o min and V L lo It is obtained by subtracting the larger of the two values ​​and multiplying the result by the proportionality constant k. ΔV o =k{min(V o max ,V L hi )-max(V o min ,V L lo )} k: ratio(0 <k≦1)

[0027] Another example is a method that determines the value based on a predetermined voltage value. In this case, ΔV o V o max and V L hi V o min and V L lo The smaller of the two values ​​obtained by subtracting the larger of the two values, and a predetermined voltage value ΔV, is used. ΔV o =min(ΔV,min(V o max ,V L hi )-max(V o min ,V L lo )) ΔV: Pre-set voltage value

[0028] Furthermore, as a third example, one can choose the smaller of the value obtained by the first example and the value obtained by the second example. ΔV o = min(ΔV,k{min(V o max ,V L hi )-max(V o min ,V L lo )})

[0029] Next, based on the values ​​obtained as described above, the upper limit V of the drooping characteristic voltage is determined. o hi and the lower limit V of the voltage in the drooping characteristic o lo And is determined. V o hi and V o lo This can be determined, for example, by the following equation (Equation 1).

number

[0030] <Switching operation from individual operation to parallel operation> In the power supply unit 100 configured as shown in Figures 2(A) and (B), the operation of switching between individual operation and parallel operation of the power supply unit 110 will be described. Specifically, when switching the operation method, the drooping characteristics of the power supply unit 110 are adjusted to suppress fluctuations in voltage or current in the power supply unit 110, and the connection state between the power supply unit 110 and the connector 120 is switched. First, the operation when switching from individual operation to parallel operation will be described.

[0031] Figure 4 shows the droop characteristics and operating point of power supply units 110A and 110B in the power supply unit 100 shown in Figure 2 during individual operation. In Figure 4, line C1 represents the droop characteristics of power supply unit 110A, and line C2 represents the droop characteristics of power supply unit 110B. In Figure 4, the operating point is indicated by a black circle "●" on the droop characteristics. During individual operation, only power supply unit 110A is in operation, and power supply unit 110B is in a stopped state (see Figure 2(B)). Therefore, in Figure 4, the operating point P1 is shown only for the droop characteristic C1 of power supply unit 110A. The droop characteristic C2 of power supply unit 110B at this time is considered the initial characteristic.

[0032] Next, in preparation for switching from individual operation to parallel operation, the control unit 150 adjusts the droop characteristics of the power supply unit 110B. Specifically, the control unit 150 adjusts the droop characteristics of the power supply unit 110B to suppress voltage or current fluctuations when the operation of the power supply unit 110B is started, according to the operating point of the power supply unit 110A which is operating in individual operation (first step).

[0033] Figure 5 illustrates the adjustment of the droop characteristic when switching from individual operation to parallel operation. The operating point P1 of power supply unit 110A in individual operation after adjusting the droop characteristic is set to voltage v(0) and current i1(0). The control unit 150 adjusts the droop characteristic C2 of power supply unit 110B so that the voltage is v(0) when the current is 0[A] (amperes). In the example shown in Figure 5, the droop characteristic C2 of power supply unit 110B shown in Figure 4 (shown as a dashed line in Figure 5) is adjusted by sliding it downwards.

[0034] After this, the control unit 150 starts operating the power supply unit 110B and turns on the switch 130B (second step). The execution order of starting the power supply unit 110B and switching on the switch 130B is not particularly limited and is selected appropriately based on the configuration of the power supply units 110A and 110B, etc.

[0035] The above operations initiate parallel operation between power supply units 110A and 110B. At this time, the operating point P1 of power supply unit 110A has a voltage of v(0) and a current of i1(0), while the operating point P2 of power supply unit 110B has a voltage of v(0) and a current of 0[A]. Since the voltages at both operating points P1 and P2 are v(0), the voltage and current of power supply unit 110A and power supply unit 110B do not change even when power supply unit 110B starts operating. Figure 5 shows the operating points P1 and P2 of both power supply units 110A and 110B.

[0036] In this explanation, we have described the case where only the droop characteristic C2 of power supply unit 110B is adjusted. Alternatively, only the droop characteristic C1 of power supply unit 110A may be adjusted, or both the droop characteristic C1 of power supply unit 110A and the droop characteristic C2 of power supply unit 110B may be adjusted. In any case, the output voltage range of connector 120 is determined, and at least one of the droop characteristics C1 and C2 is adjusted based on this output voltage range.

[0037] Next, the control unit 150 adjusts the droop characteristic C2 of the power supply unit 110B to the initial characteristic (the characteristic shown in Figure 4) (third step). After this step, the transition from individual operation to parallel operation of power supply units 110A and 110B is completed.

[0038] Figure 6 illustrates the adjustment of the droop characteristic after transitioning from individual operation to parallel operation. In the example shown in Figure 6, the droop characteristic C2 of power supply unit 110B is adjusted by sliding it upward. In Figure 6, the operating point before adjusting the droop characteristic is indicated by a white circle "○", and the operating point after adjusting the droop characteristic is indicated by a black circle "●". In parallel operation, the voltage at the operating point P1 of power supply unit 110A and the voltage at the operating point P2 of power supply unit 110B are equal. Therefore, if the droop characteristic C2 of power supply unit 110B is adjusted during parallel operation, the operating point P1 of power supply unit 110A will also change in accordance with the change in the operating point P2 of power supply unit 110B. Thus, since adjusting the droop characteristic C2 changes the operating points P1 and P2 of power supply units 110A and 110B, it is desirable to adjust the droop characteristic C2 gradually. Once the adjustment of the drooping characteristic C2 is complete, the operating point P1 of power supply unit 110A will be voltage v(t1) and current i1(t1), and the operating point P2 of power supply unit 110B will be voltage v(t1) and current i2(t1).

[0039] In the example above, the droop characteristic of the power supply unit 110B that is starting up was slid to adjust the droop characteristic when switching to parallel operation (see Figure 5). Here, the droop characteristic of the power supply unit 110B only needs to be adjusted so that the voltage when the current is 0[A] (amperes) is v(0), and is not limited to the example above. For example, the droop characteristic of the power supply unit 110B can be adjusted so that the voltage when the current is 0[A] (amperes) is v(0) by changing the slope of the droop characteristic.

[0040] Figure 7 illustrates another example of adjusting the droop characteristic when switching from individual operation to parallel operation. In the example shown in Figure 7, the voltage v(0) when the current is 0[A] (amperes) is achieved by changing the slope of the droop characteristic C2 (shown as a dashed line in Figure 7) of the power supply unit 110B shown in Figure 4. When the slope of the droop characteristic is changed and adjusted when switching to parallel operation, the adjustment of the droop characteristic after the transition to parallel operation is also performed to return the slope of the droop characteristic to its initial characteristic.

[0041] <Switching operation from parallel operation to individual operation> Next, we will explain the operation when switching from parallel operation to individual operation. When switching from parallel operation to individual operation, as with switching from individual operation to parallel operation, the drooping characteristics are adjusted in order to suppress fluctuations in the voltage or current of power supply units 110A and 110B.

[0042] Figure 8 illustrates the adjustment of the drooping characteristics when switching from parallel operation to individual operation. In parallel operation, both power supply units 110A and 110B are in operation (see Figure 2(B)). At this time, the operating point P1 of power supply unit 110A is assumed to be voltage v(t2) and current i1(t2), and the operating point P2 of power supply unit 110B is assumed to be voltage v(t2) and current i2(t2).

[0043] In Figure 8, the droop characteristic C2 of power supply unit 110B before adjustment is shown by a thin dashed line, and the operating point P2 is indicated by a white circle "〇". When switching the operating state of power supply units 110A and 110B from parallel operation to individual operation, the control unit 150 first adjusts the droop characteristic C2 of power supply unit 110B so that the current is 0 [A] (amperes) (4th step). In the example shown in Figure 8, the droop characteristic C2 of power supply unit 110B during parallel operation (shown by a dashed line) is adjusted by sliding it downwards. In Figure 8, the droop characteristic C2 of power supply unit 110B after adjustment is shown by a thick dashed line, and the operating point P2 is indicated by a black circle "●". With the adjusted droop characteristic C2, the operating point P2 is voltage v(t3) and current i2(t3) = 0 [A].

[0044] Furthermore, as shown in Figure 8, when the droop characteristic C2 of the power supply unit 110B is adjusted and the operating point P2 moves, the operating point P1 of the power supply unit 110A also moves accordingly. In Figure 8, the operating point P1 of the power supply unit 110B before adjustment of the droop characteristic C2 is indicated by a white circle "○", and the operating point P1 after adjustment is indicated by a black circle "●". In the example shown in Figure 8, the operating point P1 of the power supply unit 110A after adjusting the droop characteristic C2 of the power supply unit 110B is voltage v(t3) and current i1(t3).

[0045] After this, the control unit 150 turns off switch 130B and stops power supply unit 110B (5th step). The execution order of stopping power supply unit 110B and switching switch 130B is not particularly limited and is selected appropriately based on the configuration of power supply units 110A and 110B. At the point when power supply unit 110B stops and switch 130B is turned off, the current at operating point P2 is 0[A], so even if power supply unit 110B stops, the current and voltage of power supply unit 110A do not change.

[0046] In the example above, the power supply units 110A and 110B are shown to be controlled by switching from individual operation to parallel operation (steps 1 to 3), and then switching from parallel operation to individual operation (steps 4 and 5). This procedure is just one example of the operation of the power supply unit 100, and steps 1 to 5 are simply steps indicating the order of execution. For example, the initial state could be parallel operation, and then the operation could be switched to individual operation.

[0047] Furthermore, the above example described a case where only the droop characteristic C2 of power supply unit 110B is adjusted when switching between the operation of power supply units 110A and 110B. In contrast, it is also possible to adjust only the droop characteristic C1 of power supply unit 110A, or to adjust both the droop characteristic C1 of power supply unit 110A and the droop characteristic C2 of power supply unit 110B. In either case, the output voltage range of connector 120A (first range) and the output voltage range of connector 120B (second range) are determined, and the droop characteristic C1 is adjusted based on the first range, and the droop characteristic C2 is adjusted based on the second range.

[0048] 〇Second Embodiment <Other configuration examples to enable switching of connection states> Figure 9 shows a power supply unit 100 whose connection state can be switched. Figure 9(A) shows an example of the configuration of the power supply unit 100. Figure 9(B) shows an example of the state of the power supply unit 110 and the switch 130. For simplicity, the switching of the connection between the two power supply units 110 will be explained.

[0049] In the example shown in Figure 9(A), the two power supply units 110 are distinguished as power supply unit 110A and power supply unit 110B. If there is no need to distinguish between the two power supply units 110A and 110B, they are simply referred to as power supply unit 110. Also, in the example shown in Figure 9(A), two connectors 120 are provided, corresponding to power supply units 110A and 110B respectively. Therefore, the connector 120 corresponding to power supply unit 110A is referred to as connector 120A, and the connector 120 corresponding to power supply unit 110B is referred to as connector 120B. If there is no need to distinguish between connectors 120A and 120B, they are simply referred to as connector 120.

[0050] Furthermore, in the example shown in Figure 9(A), three switches 130 are provided. One of the three switches 130 corresponds to power supply unit 110A, another corresponds to power supply unit 110B, and yet another is provided on the connecting wire that connects the output of power supply unit 110A to the output of power supply unit 110B. Therefore, the switch 130 corresponding to power supply unit 110A will be referred to as switch 130A, the switch 130 corresponding to power supply unit 110B will be referred to as switch 130B, and the switch 130 provided on the connecting wire that connects the output of power supply unit 110A to the output of power supply unit 110B will be referred to as switch 130C. When there is no need to distinguish between these three switches 130A, 130B, and 130C, they are simply referred to as switch 130.

[0051] Furthermore, Figure 9(A) shows external devices 210A and 210B, which have connectors 201A and 201B connected to connectors 120A and 120B. Regarding external devices 210A and 210B and connectors 201A and 201B, if there is no need to distinguish between them, they are simply referred to as external device 210 and connector 201.

[0052] In the configuration example shown in Figure 9(A), power supply unit 110A is connected to connector 120A via switch 130A, and also to connector 120B via switches 130C and 130B. Power supply unit 110B is connected to connector 120B via switch 130B, and also to connector 120A via switches 130C and 130A. When connector 201 of external device 210 is connected to connector 120 of power supply unit 100, power is supplied to external device 210 from connector 120.

[0053] The control unit 150 controls the power supply units 110A and 110B and switches 130A, 130B, and 130C to switch the connection status between power supply units 110A and 110B and connectors 120A and 120B, as well as the operating status of power supply unit 110, in individual operation and parallel operation. In this case, in individual operation, power supply unit 110A outputs power via connector 120A, and power supply unit 110B outputs power via connector 120B.

[0054] As shown in Figure 9(A), in this example, during individual operation, power supply unit 110A and power supply unit 110B each supply power to external devices 210A and 210B individually. Then, as shown in Figure 9(B), during individual operation, power supply unit 110A and power supply unit 110B are both in operation. Switches 130A and 130B are both ON, and switch 130C is OFF. As a result, only the output power of power supply unit 110A is supplied to external device 210A, and the output power of power supply unit 110B is not supplied to external device 210A. Also, only the output power of power supply unit 110B is supplied to external device 210B, and the output power of power supply unit 110A is not supplied to external device 210B.

[0055] On the other hand, in parallel operation, both power supply units 110A and 110B are in operation. Switches 130A, 130B, and 130C are all turned ON. As a result, the output power of both power supply unit 110A and power supply unit 110B is supplied to the external devices 210A and 210B.

[0056] <Switching connection status> Next, the operation of switching the connection state of the power supply unit 110 will be described. As described in the first embodiment, when switching the connection state of the power supply unit 110 from an individual state to a parallel state, or from a parallel state to an individual state, the current or voltage at the output of the power supply unit 110 fluctuates. In this embodiment as well, when switching the connection state of the power supply unit 110, the control unit 150 suppresses the fluctuation of current or voltage by adjusting the drooping characteristics of the power supply unit 110.

[0057] <Switching operation from individual operation to parallel operation> In the power supply unit 100 configured as shown in Figures 9(A) and (B), the operation of switching between individual operation and parallel operation of the power supply unit 110 will be described. Specifically, when switching the operation method, the drooping characteristics of the power supply unit 110 are adjusted to suppress voltage or current fluctuations in the power supply unit 110, and the connection state between the power supply unit 110 and the connector 120 is switched. First, the operation when switching from individual operation to parallel operation will be described.

[0058] Figure 10 shows the droop characteristics and operating points of power supply units 110A and 110B in the power supply unit 100 shown in Figure 9 when they are operated individually. In Figure 10, line C1 shows the droop characteristics of power supply unit 110A, and line C2 shows the droop characteristics of power supply unit 110B. Also in Figure 10, the operating point is indicated by a black circle "●" on the droop characteristics. When operated individually, power supply units 110A and 110B are operated separately. Therefore, in Figure 10, the droop characteristics C1 of power supply unit 110A and C2 of power supply unit 110B are set individually. The current and voltage at the operating point P1 of power supply unit 110A and the current and voltage at the operating point P2 of power supply unit 110B are determined independently.

[0059] Note that the statement that the current and voltage at operating point P1 and the current and voltage at operating point P2 are determined independently simply means that operating point P1 and operating point P2 are not related. Therefore, it is not necessarily the case that the current at operating point P1 and the current at operating point P2 are different values, or that the voltage at operating point P1 and the voltage at operating point P2 are different values. Depending on the type of connected external equipment 210, or the control of power supply units 110A and 110B by the control unit 150, the current and voltage values ​​at operating point P1 and operating point P2 may be the same. In the example shown in Figure 10, the current and voltage values ​​at operating point P1 are different from those at operating point P2 of power supply unit 110B.

[0060] Next, in preparation for switching from individual operation to parallel operation, the control unit 150 adjusts the drooping characteristics of one of the power supply units 110A and 110B. Here, as an example, the drooping characteristics of power supply unit 110B are adjusted. Specifically, the control unit 150 adjusts the drooping characteristics of power supply unit 110B to suppress voltage or current fluctuations when the connection state of power supply units 110A and 110B is switched, according to the operating point of power supply unit 110A which is operating in individual operation (first step).

[0061] Figure 11 illustrates the adjustment of the droop characteristics when switching from individual operation to parallel operation. The operating point P1 of power supply unit 110A in individual operation is set to voltage v1(0) and current i1(0). The operating point P2 of power supply unit 110B in individual operation after adjusting the droop characteristics is set to voltage v2(0) and current i2(0). Before adjusting the droop characteristics (see Figure 10), v1≠v2 and current i1≠current i2. In Figure 11, the operating point P1 of power supply unit 110A is indicated by a black circle "●". In Figure 11, the operating point P2 of power supply unit 110B before adjusting the droop characteristics is indicated by a white circle "○", and the operating point P2 after adjusting the droop characteristics is indicated by a black circle "●".

[0062] The control unit 150 adjusts the droop characteristic C2 of the power supply unit 110B so that the voltage becomes v1(0). In the example shown in Figure 11, the droop characteristic C2 of the power supply unit 110B shown in Figure 10 (shown as a dashed line in Figure 11) is slid downward to make the adjustment. After this, the control unit 150 starts the operation of the power supply unit 110B and turns on the switch 130C (second step).

[0063] The above operations initiate parallel operation between power supply units 110A and 110B. At this time, the operating point P1 of power supply unit 110A has a voltage v1(0) and a current i1(0), while the operating point P2 of power supply unit 110B has a voltage v2(0)=v1(0) and a current i2(0). Since the voltages at operating points P1 and P2 are the same (v2(0)=v1(0)), the voltage and current of power supply unit 110A and power supply unit 110B do not fluctuate even when parallel operation between power supply units 110A and 110B is initiated.

[0064] In this explanation, we have described the case where only the droop characteristic C2 of power supply unit 110B is adjusted. Alternatively, only the droop characteristic C1 of power supply unit 110A may be adjusted, or both the droop characteristic C1 of power supply unit 110A and the droop characteristic C2 of power supply unit 110B may be adjusted. In any case, the output voltage range of connector 120A (first range) and the output voltage range of connector 120B (second range) are determined, and at least one of the droop characteristics C1 and C2 is adjusted based on these output voltage ranges.

[0065] Next, the control unit 150 adjusts the droop characteristic C2 of the power supply unit 110B to the characteristic during individual operation (the characteristic shown in Figure 10) (third step). After this step, the transition from individual operation to parallel operation of power supply units 110A and 110B is completed.

[0066] Figure 12 illustrates the adjustment of the droop characteristic after transitioning from individual operation to parallel operation. In the example shown in Figure 12, the droop characteristic C2 of power supply unit 110B is adjusted by sliding it upward. In Figure 12, the operating point before adjusting the droop characteristic is indicated by a white circle "○", and the operating point after adjusting the droop characteristic is indicated by a black circle "●". The voltage at the operating point P1 of power supply unit 110A and the voltage at the operating point P2 of power supply unit 110B are equal. Therefore, if the droop characteristic C2 of power supply unit 110B is adjusted during parallel operation, the operating point P1 of power supply unit 110A will also change in accordance with the change in the operating point P2 of power supply unit 110B. Thus, since adjusting the droop characteristic C2 changes the operating points P1 and P2 of power supply units 110A and 110B, it is desirable to adjust the droop characteristic C2 gradually. Once the adjustment of the drooping characteristic C2 is complete, the operating point P1 of power supply unit 110A will be voltage v(t1) and current i1(t1), and the operating point P2 of power supply unit 110B will be voltage v(t1) and current i2(t1).

[0067] In the above example, the droop characteristic of the power supply unit 110B that is starting up was slid to adjust the droop characteristic when switching to parallel operation (see Figure 11). Here, the droop characteristic of the power supply unit 110B only needs to be adjusted so that the voltage when the current is i2(0) is v2(0)=v1(0), and is not limited to the above example. For example, the droop characteristic of the power supply unit 110B can be adjusted so that the voltage when the current is i2(0) is v2(0)=v1(0).

[0068] Furthermore, in the above example, the droop characteristics C1 of power supply unit 110A and C2 of power supply unit 110B in individual operation are not particularly limited. In contrast, before switching from individual operation to parallel operation, the droop characteristics C1 and C2 may be updated based on the upper and lower limits of the input voltage of external devices 210A and 210B, etc.

[0069] Figure 13 shows the input voltage of the external device 210 during individual operation and parallel operation. Figure 13(A) shows the upper limit of the input voltage of the external device 210 during individual operation and parallel operation. In Figure 13(A), V 1L hi This is the upper limit of the input voltage of the external device 210 that is powered by the power supply unit 110A. 2L hi This is the upper limit of the input voltage of the external device 210 that is powered by the power supply unit 110B. 1L1 hi ,···,V 1LN hi This is the upper limit of the input voltage for N external devices 210 that are powered individually from power supply unit 110A. 2L1 hi ,···,V 2LM hi This is the upper limit of the input voltage for the M units of external equipment 210, which are powered individually by the power supply unit 110B.

[0070] Figure 13(B) shows the lower limit of the input voltage of the external equipment 210 during individual operation and parallel operation. In Figure 13(B), V 1L lo This is the lower limit of the input voltage of the external device 210 powered by the power supply unit 110A. 2L lo This is the lower limit of the input voltage of the external device 210 that is powered by the power supply unit 110B.1L1 lo ,···,V 1LN lo This is the lower limit of the input voltage for N external devices 210 that are powered individually from power supply unit 110A. 2L1 lo ,···,V 2LM lo This is the lower limit of the input voltage for the M units of external equipment 210, which are powered individually by the power supply unit 110B.

[0071] The control unit 150 determines the droop characteristics during parallel operation based on the upper and lower limits of the input voltage of the external device 210 during parallel operation, as shown in Figure 13. Then, while maintaining individual operation, it adjusts from the droop characteristics during individual operation to the droop characteristics during parallel operation. The upper and lower limits of the input voltage of the external device 210 may be determined, for example, by communication between the power supply unit 100 and the external device 210. Alternatively, they may be set by means of a switch or other means. Furthermore, predetermined values ​​may be adopted for each connector.

[0072] <Switching operation from parallel operation to individual operation> Next, the operation when switching from parallel operation to individual operation will be explained. When switching from parallel operation to individual operation, as with switching from individual operation to parallel operation, the drooping characteristics are adjusted in order to suppress fluctuations in the voltage or current of power supply units 110A and 110B. When switching from parallel operation to individual operation, the power supply unit 100 is provided with a configuration to detect internal current information in order to obtain the current information necessary to adjust the drooping characteristics.

[0073] FIG. 14 is a diagram showing a configuration for detecting information on the current inside the power supply device 100. In this configuration, the currents at the positions of S1, S2, and S3 shown in FIG. 14 are detected. At S1, the output current i1(t) of the power supply unit 110A is detected. At S2, the output current i2(t) of the power supply unit 110B is detected. At S3, the current supplied to any one of the external devices 210A and 210B connected to the connectors 120A and 120B of the power supply device 100 is detected. Which external device 210 among the externally connected devices 210 operating in parallel the current supplied to is detected is specified according to, for example, the power supply unit 110 which is the target for adjusting the droop characteristic when switching the operation. Here, the droop characteristic of the power supply unit 110B is adjusted. Therefore, S3 is set at the position between the switch 130B and the connector 120B, and the current i L 2 (t) supplied to the external device 210B is detected.

[0074] As shown in FIG. 14, the output current i1(t) of the power supply unit 110A is detected at the position between the output of the power supply unit 110A and the branching position where it branches to the switches 130A and 130C. Also, the output current i2(t) of the power supply unit 110B is detected at the position between the output of the power supply unit 110B and the branching position where it branches to the switches 130B and 130C. Also, the current i L2 (t) supplied to the external device 210B is detected at the position between the connector 120B to which the power of the power supply unit 110B is supplied and the switch 130B in the individual operation.

[0075] Figure 15 illustrates the adjustment of the droop characteristics when switching from parallel operation to individual operation. In parallel operation, the operating point P1 of power supply unit 110A is voltage v(t2) and current i1(t2), and the operating point P2 of power supply unit 110B is voltage v(t2) and current i2(t2). In Figure 15, the operating points P1 and P2 before adjusting the droop characteristics are indicated by white circles "○", and the operating points P1 and P2 after adjusting the droop characteristics are indicated by black circles "●". In Figure 15, the droop characteristic C2 of power supply unit 110B before adjusting the droop characteristics is shown by a thin dashed line, and the droop characteristic C2 of power supply unit 110B after adjusting the droop characteristics is shown by a thick dashed line.

[0076] When switching the operating state of power supply units 110A and 110B from parallel operation to individual operation, the control unit 150 first checks the current i2(t) of power supply unit 110B and the current i of external device 210B. L2 Adjust the droop characteristic C2 of the power supply unit 110B to match (t). In the example shown in Figure 15, the droop characteristic C2 (shown as a dashed line) of the power supply unit 110B during parallel operation is adjusted by sliding it downwards (step 4). In the adjusted droop characteristic C2, the operating point P2 is voltage v(t3) and current i2(t3) = i L2 (t)

[0077] Furthermore, as shown in Figure 15, when the droop characteristic C2 of the power supply unit 110B is adjusted and the operating point P2 moves, the operating point P1 of the power supply unit 110A also moves accordingly. In the example shown in Figure 15, the operating point P1 of the power supply unit 110A after adjusting the droop characteristic C2 is voltage v(t3) and current i1(t3).

[0078] After this, the control unit 150 turns off switch 130C and switches to individual operation of power supply unit 110A and power supply unit 110B (5th step). At the point when switch 130C is turned off, the current i2(t3) at the operating point P2 of power supply unit 110B is equal to the current i of external device 210B. L2Since it is equal to (t), the current and voltage of power supply unit 110B do not fluctuate even when switching to individual operation. Also, after adjusting the drooping characteristics of power supply unit 110B, the current i1(t3) at operating point P1 that has moved along with the movement of operating point P2 is equal to the current in individual operation of power supply unit 110A, so the current and voltage of power supply unit 110A do not fluctuate even when switching to individual operation.

[0079] In individual operation, when power supply unit 110A and power supply unit 110B each supply power to external devices 210A and 210B individually, the control unit 150 further adjusts the droop characteristic C2 of power supply unit 110B. Specifically, the control unit 150 adjusts the droop characteristic C2 of power supply unit 110B to the characteristics during initial individual operation (the characteristics shown in Figure 10).

[0080] Figure 16 illustrates the adjustment of the droop characteristic after transitioning from parallel operation to individual operation. In Figure 16, the operating point before adjusting the droop characteristic is indicated by a white circle "○", and the operating point after adjusting the droop characteristic is indicated by a black circle "●". As explained with reference to Figure 15, the operating point P2 of the power supply unit 110B when switching from parallel operation to individual operation was voltage v2(t3) (=v(t3)) and current i2(t3). In Figure 16, the droop characteristic C2 of the power supply unit 110B shown in Figure 15 (shown as a dashed line in Figure 16) is slid upward to return to the characteristics during individual operation (characteristics shown in Figure 10). Note that adjusting the droop characteristic C2 changes the operating point P2 of the power supply unit 110B, so it is desirable to adjust the droop characteristic C2 gradually.

[0081] Once the adjustment of the droop characteristic C2 is complete, the operating point P2 of power supply unit 110B will be voltage v2(t4) and current i2(t4). Since power supply units 110A and 100B are operated individually, even if the droop characteristic C2 of power supply unit 110B is adjusted and the operating point P2 moves, the droop characteristic C1 and operating point P1 of power supply unit 110A will not change. Therefore, the operating point P1 of power supply unit 110A remains v(t3) and current i1(t3) (see Figure 15).

[0082] In the example above, the power supply units 110A and 110B are shown to be controlled by switching from individual operation to parallel operation (steps 1 to 3), and then switching from parallel operation to individual operation (steps 4 and 5). This procedure is just one example of the operation of the power supply unit 100, and steps 1 to 5 are simply steps indicating the order of execution. For example, the initial state could be parallel operation, and then the operation could be switched to individual operation.

[0083] Furthermore, the above example described a case where only the droop characteristic C2 of power supply unit 110B is adjusted when switching between the operation of power supply units 110A and 110B. In contrast, it is also possible to adjust only the droop characteristic C1 of power supply unit 110A, or to adjust both the droop characteristic C1 of power supply unit 110A and the droop characteristic C2 of power supply unit 110B. In either case, the output voltage range of connector 120A (first range) and the output voltage range of connector 120B (second range) are determined, and the droop characteristic C1 is adjusted based on the first range, and the droop characteristic C2 is adjusted based on the second range.

[0084] <Variations of the switching operation from parallel operation to individual operation> In the above example of operation, the output currents of power supply units 110A and 110B were detected using the configuration shown in Figure 14, and the drooping characteristics of power supply unit 110B were adjusted. However, the output currents of power supply units 110A and 110B may be detected and the drooping characteristics of power supply unit 110B adjusted using a configuration different from that shown in Figure 14.

[0085] Figure 17 shows another example configuration for detecting current information inside the power supply unit 100. In this configuration, the currents at positions S1, S2, and S4 shown in Figure 17 are detected. At S1, the output current i1(t) of power supply unit 110A is detected. At S2, the output current i2(t) of power supply unit 110B is detected. At S4, the current i passing through switch 130C is detected. 12 (t) is detected.

[0086] In the configuration shown in FIG. 17, when adjusting the droop characteristics of the power supply unit 110B (or the power supply unit 110A) in the above-described fourth step (see FIG. 15), the control unit 150 sets the current i 12 (t) to 0 [A]. Specifically, the control unit 150 observes the change in the current i 12 (t) while gradually adjusting the droop characteristics of the power supply unit 110B, and controls the droop characteristics of the power supply unit 110B until i 12 (t) = 0 [A].

[0087] <Other modification examples> Also, in the above-described second embodiment, in the third step, the droop characteristic C2 of the power supply unit 110B was adjusted to the characteristic during the initial individual operation (the characteristic shown in FIG. 10) (see FIG. 12). In contrast, the droop characteristic after the transition to parallel operation may be controlled to be adjusted to the droop characteristic during individual operation determined based on the information of the external device 210 that is powered during individual operation.

[0088] Also, in the above-described first and second embodiments, an example in which the number of the power supply units 110 is two has been described. However, the number of the power supply units 110 provided in the power supply device 100 may be three or more. Also, in the second embodiment, an example in which the number of the connectors 120 is two has been described. However, the number of the connectors 120 may be three or more. Also, in the first embodiment and the second embodiment, an example in which one connector 120 is connected to one switch 130 has been described. However, two or more connectors 120 may be connected in parallel to one switch 130.

[0089] In the first and second embodiments described above, examples were used where the relationship between the output current and the output voltage is a linear function as the drooping characteristic of each power supply unit 110 (Figures 4-8, 10-12, 15, and 16). However, the relationship between the output current and the output voltage in the drooping characteristic is not limited to the above examples; any characteristic in which the output voltage monotonically decreases as the output current increases is acceptable. Therefore, for example, in a graph showing the relationship between the output current and the output voltage, the change in output voltage in response to a change in output current may be represented by a curve or by multiple line segments with different angles, indicating a characteristic in which the change in output voltage differs depending on the value of the output current.

[0090] Furthermore, in the first and second embodiments, examples were shown where the voltage value at the same current value was higher for the drooping characteristic C1 of power supply unit 110A than for the drooping characteristic C2 of power supply unit 110B. In contrast, the voltage at the same current value may be lower for the drooping characteristic C1 of power supply unit 110A than for the drooping characteristic C2 of power supply unit 110B. Also, the voltage at the same current value may be the same for the drooping characteristic C1 of power supply unit 110A and the drooping characteristic C2 of power supply unit 110B.

[0091] Furthermore, the relationship between the voltage of drooping characteristic C1 and the voltage of drooping characteristic C2 may differ depending on the current value. In this case, the graph showing the relationship between output current and output voltage will show that drooping characteristic C1 and drooping characteristic C2 intersect.

[0092] Furthermore, the example of setting the drooping characteristic explained with reference to Figure 3 does not distinguish between each of the multiple power supply units 110, but the upper limit V of the output voltage in each power supply unit 110 o max lower limit of output voltage V o min , upper limit of output current I o max These can all be different.

[0093] Furthermore, in the first and second embodiments described above, the detection of current in the circuit within the power supply unit 110 is not limited to detection using a current sensor. For example, detection may be performed based on command values ​​or estimated values ​​within the power supply unit 110. Alternatively, detection may be performed based on detected values, command values, or estimated values ​​of an external power supply. In this case, for example, communication may be performed between the power supply unit 110 and the external power supply to obtain detected values, command values, estimated values, etc., of the external power supply.

[0094] In the above embodiment, the power supply unit 110 was described as being configured to supply DC power to the connector 120 in only one direction. However, the power supply unit 110 may be configured to supply DC power in both directions. When the power supply unit 110 is configured to supply DC power in both directions, it is preferable that the power supply units 110 connected in parallel be controlled so that the direction of DC power supply is the same. Specifically, when power is supplied from one power supply unit 110 to the connector 120, power is also supplied to the connector 120 from another power supply unit 110 connected in parallel. Also, when power is supplied from the connector 120 to one power supply unit, power is also supplied from the connector 120 to another power supply unit connected in parallel.

[0095] Furthermore, in the above embodiment, the outputs of the multiple power supply units 110 were described as being electrically isolated from each other. In contrast, the outputs of the multiple power supply units 110 may be electrically connected to each other's reference potentials.

[0096] <Other power supply configuration examples> Figure 18 shows another example configuration of the power supply unit 100. In the example shown in Figure 18, only the AC power supply 300 is shown as the power source. Note that in Figure 18, the control unit 150, etc., are the same as those shown in Figure 1 and are therefore omitted from the description.

[0097] In the configuration example shown in Figure 1, the power supply unit 110 has only a DC / DC converter 111. The power supply device 100 converts the AC power supplied from the AC power supply 300 into DC power using an AC / DC converter 161, and then distributes it to each power supply unit 110. In contrast, in the configuration shown in Figure 18, each power supply unit 180 is equipped with both an AC / DC converter 181 and a DC / DC converter 182. The power supply device 100 distributes the AC power supplied from the AC power supply 300 to each power supply unit 180 as AC power. Each power supply unit 180 converts the supplied AC power into DC power using an AC / DC converter 181, and then further converts it using a DC / DC converter 182. Each power supply unit 180 then supplies the converted DC power to the connector 120.

[0098] In the power supply unit 100 shown in Figures 1 and 18, each power supply unit may share a circuit board and components, or each power supply unit may be configured with a separate circuit board and components. Alternatively, the power supply unit 100 may be provided with slots into which power supply units can be detachably mounted. With such a configuration, if a failure occurs in an individual power supply unit, it can be easily dealt with by replacing the power supply unit individually. Furthermore, various modifications and alternative configurations that do not deviate from the scope of the technical concept of this disclosure are included in this disclosure.

[0099] <Examples of applications for power supply unit 100> Figure 19 shows an example of the application of the power supply unit 100. The example shown in Figure 19 is an example of a power supply system in a house. In Figure 19, AC power is supplied to the power supply unit 100 from the grid power supply via a power meter 301 and a distribution board 302. DC power is also supplied to the power supply unit 100 from a solar panel power supply 401 via a junction box 402. DC power is also supplied to the power supply unit 100 from a storage battery 501. The power supply unit 100 receives this AC power and DC power, converts it, and supplies DC power to external devices 210 connected by various connection methods. In Figure 19, examples of external devices 210 to which power is supplied include a water heater and an outdoor unit of an air conditioner.

[0100] <Effects> The power supply unit 100 of the present disclosure comprises a first power supply unit 110 and a second power supply unit 110 capable of supplying DC power, a switch 130 capable of switching between an ON state in which the output of the first power supply unit 110 and the output of the second power supply unit 110 are connected in parallel and an OFF state in which they are not connected in parallel, and a control unit 150 that controls the first power supply unit 110, the second power supply unit 110 and the switch 130, wherein the control unit 150 has a first drooping characteristic in which the output voltage decreases as the output current of the first power supply unit 110 increases. The first power supply unit 110 is controlled in such a way that it exhibits a second drooping characteristic where the output voltage decreases as the output current of the second power supply unit 110 increases. The first step is to adjust the first or second drooping characteristic so that the output voltage of the first power supply unit 110 matches the output voltage of the second power supply unit 110 when the switch 130 is in the off state. After the first step, the second step is to switch the switch 130 from the off state to the on state. In this case, by adjusting the drooping characteristic and switching the connection state, fluctuations in current or voltage when switching from individual operation to parallel operation can be suppressed. Here, after the second step, the control unit 150 performs a third step in which it adjusts the first or second drooping characteristic and changes the output current of the first power supply unit 110 and the output current of the second power supply unit 110. In this case, the first power supply unit 110 and the second power supply unit 110 can share the current supplied to the external device in a parallel connection. The system further includes a first connector 120 connected to the first power supply unit 110 and a second connector 120 connected to the second power supply unit 110. The control unit 150 determines a first range of output voltage for the first connector 120 and a second range of output voltage for the second connector 120, and in the first step, adjusts at least one of the first droop characteristic and the second droop characteristic based on both the first and second ranges. In this case, the droop characteristics of the power supply units when switching from individual operation to parallel operation can be adjusted to appropriately control the output voltage within the range determined for each connector. Furthermore, the control unit 150 performs a fourth step of adjusting the first or second drooping characteristic so that the current flowing through the switch 130 becomes 0 amperes when the switch 130 is in the ON state, and after the first step, performs a fifth step of switching the switch 130 from the ON state to the OFF state. In this case, fluctuations in current or voltage when switching from parallel operation to individual operation can be suppressed. The system further includes a first connector 120 connected to the first power supply unit 110 and a second connector 120 connected to the second power supply unit 110. The control unit 150 determines a first range of output voltage for the first connector 120 and a second range of output voltage for the second connector 120. After the fifth step, it adjusts the first droop characteristic based on the first range, or the second droop characteristic based on the second range. In this case, the droop characteristics of the power supply units when switching from parallel operation to individual operation can be adjusted to appropriately control the output voltage within the range determined for each connector. Furthermore, the power supply unit 110 further comprises a DC / DC converter 162 configured to be connectable to a DC power supply 400, an AC / DC converter 161 configured to be connectable to an AC power supply 300, and a DC bus 190 connecting the DC / DC converter 162 and the AC / DC converter 161. The first power supply unit 110 is connected to the DC bus 190 and can supply DC power obtained by converting the DC power of the DC bus 190, and the second power supply unit 110 is connected to the DC bus 190 and can supply DC power obtained by converting the DC power of the DC bus 190. In this case, the power supplied from the DC power supply 400 and the AC power supply 300 can suppress fluctuations in current or voltage when switching between individual operation and parallel operation. Furthermore, the power supply device 100 of the present disclosure includes a first power supply unit 110 and a second power supply unit 110 capable of supplying DC power, a switch 130 that can switch between an ON state in which the output of the first power supply unit 110 and the output of the second power supply unit 110 are connected in parallel and an OFF state in which they are not connected in parallel, and a control unit 150 that controls the first power supply unit 110, the second power supply unit 110 and the switch 130. The control unit 150 controls the first power supply unit 110 so that it has a first drooping characteristic in which the output voltage decreases as the output current of the first power supply unit 110 increases, and controls the second power supply unit 110 so that it has a second drooping characteristic in which the output voltage decreases as the output current of the second power supply unit 110 increases. The control unit 150 adjusts the first drooping characteristic or the second drooping characteristic so that the current flowing through the switch 130 is 0 amperes when the switch 130 is in the ON state, and switches the switch 130 from the ON state to the OFF state. In this case, by adjusting the drooping characteristics and switching the connection state, fluctuations in current or voltage when switching from parallel operation to individual operation can be suppressed.

[0101] Although embodiments have been described above, the technical scope of this disclosure is not limited to the embodiments described above. It is clear from the claims that combinations of two or more of the above embodiments, as well as various modifications or improvements to the above embodiments, are also included in the technical scope of this disclosure. [Explanation of Symbols]

[0102] 100...Power supply unit, 110...Power supply unit, 111...DC / DC converter, 120...Connector, 130...Switch, 150...Control unit, 161...AC / DC converter, 162...DC / DC converter, 180...Power supply unit, 181...AC / DC converter, 182...DC / DC converter

Claims

1. A first power supply unit and a second power supply unit capable of supplying DC power, A switch that can switch between an ON state in which the output of the first power supply unit and the output of the second power supply unit are connected in parallel, and an OFF state in which they are not connected in parallel, The system comprises a first power supply unit, a second power supply unit, and a control unit that controls the switch, The control unit, The first power supply unit is controlled such that it exhibits a first drooping characteristic in which the output voltage decreases as the output current of the first power supply unit increases. The second power supply unit is controlled such that the output voltage decreases as the output current of the second power supply unit increases, resulting in a second drooping characteristic. With the switch in the off state, a first step is performed to adjust the first or second drooping characteristic so that the output voltage of the first power supply unit matches the output voltage of the second power supply unit. After the first step, a second step is performed to switch the switch from the off state to the on state. power supply.

2. The power supply device according to claim 1, wherein the control unit performs a third step after the second step of adjusting the first drooping characteristic or the second drooping characteristic and changing the output current of the first power supply unit and the output current of the second power supply unit.

3. A first connector connected to the first power supply unit, The device further comprises a second connector connected to the second power supply unit, The control unit, Determine the first range of the output voltage of the first connector and the second range of the output voltage of the second connector. In the first step, adjust at least one of the first drooping characteristic and the second drooping characteristic based on both the first range and the second range. The power supply device according to claim 1.

4. The control unit, A fourth step is performed in which the first or second drooping characteristic is adjusted so that the current flowing through the switch becomes 0 amperes when the switch is in the ON state. After the first step, a fifth step is performed to switch the switch from the ON state to the OFF state. The power supply device according to claim 1.

5. A first connector connected to the first power supply unit, The device further comprises a second connector connected to the second power supply unit, The control unit, Determine the first range of the output voltage of the first connector and the second range of the output voltage of the second connector. After the fifth step, the first drooping characteristic is adjusted based on the first range, or the second drooping characteristic is adjusted based on the second range. The power supply device according to claim 4.

6. A converter circuit configured to be connectable to a DC power supply, An inverter circuit configured to be connectable to an AC power source, The system further comprises a DC bus connecting the converter circuit and the inverter circuit, The first power supply unit is connected to the DC bus and is capable of supplying DC power obtained by converting the DC power of the DC bus into power. The second power supply unit is connected to the DC bus and is capable of supplying DC power obtained by converting the DC power of the DC bus into DC power. A power supply device according to any one of claims 1 to 5.

7. A first power supply unit and a second power supply unit capable of supplying DC power, A switch that can switch between an ON state in which the output of the first power supply unit and the output of the second power supply unit are connected in parallel, and an OFF state in which they are not connected in parallel, The system comprises a first power supply unit, a second power supply unit, and a control unit that controls the switch, The control unit, The first power supply unit is controlled such that it exhibits a first drooping characteristic in which the output voltage decreases as the output current of the first power supply unit increases. The second power supply unit is controlled such that the output voltage decreases as the output current of the second power supply unit increases, resulting in a second drooping characteristic. The first or second drooping characteristic is adjusted so that when the switch is in the ON state, the current flowing through the switch becomes 0 amperes. Switching the aforementioned switch from the ON state to the OFF state, power supply.

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