Power Supply System

Abstract

To provide a power supply system 1 for prohibiting power supply from an auxiliary power source 3 to an in-house electric load 6 when at least one of relay switches 12a, 12b, 12c, 12d fails.SOLUTION: When a controller 13a receives a power supply permission notification from a controller 26a and determines that respective relay switches 12a, 12b, 12c, 12d are normal, the controller 26a controls an inverter circuit 21. Therefore, the inverter circuit 21 converts an output voltage of an AC-DC converter into an AC voltage to output it to an in-house electric load 6. When the controller 13a receives the power supply permission notification from the controller 26a to determine that at least one of the relay switches 12a, 12b, 12c, 12d is out of order, all the relay switches 12a, 12b, 12c, 12d are turned off. The controller 13a prohibits power supply from an auxiliary power supply 3 to the in-house electric load 6.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power supply system. [Background technology]

[0002] Conventionally, there has been provided a power management system that converts DC voltage supplied from a storage battery in an automobile via a charging / discharging stand into AC voltage during a power outage and outputs it to an electrical load in a house (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-160593 Summary of the Invention [Problem to be solved by the invention]

[0004] Using the above-mentioned power management system as a reference, the inventors have studied a power supply system that includes an AC-DC converter that converts the AC voltage output from the auxiliary power supply into a DC voltage, and a DC-AC converter that converts the output voltage of the AC-DC converter into an AC voltage and outputs it to an electrical load in the home.

[0005] In this power supply system, in order to prevent power from being supplied to the electrical load simultaneously from both the system power supply and the auxiliary power supply, it is considered necessary to provide an input-side relay switch in series with the AC-DC converter between the input terminal of the DC-AC converter and the auxiliary power supply.

[0006] In addition, it is considered necessary to provide an output side relay switch that opens and closes between the system power supply and the electrical load.

[0007] However, if the input side relay switch remains on due to welding or the like, when the output side relay switch is turned on to supply power from the system power supply to the electrical load, both the input side relay switch and the output side relay switch will be turned on at the same time.

[0008] In view of the above, it is an object of the present invention to provide a power supply system that prohibits power supply from an auxiliary power supply to an electrical load when a relay switch fails. [Means for solving the problem]

[0009] In order to achieve the above object, in the invention described in claim 1, in a power supply system, an AC / DC converter (11) having a first input terminal (11a) and a second input terminal (11b) to which an AC voltage output from an auxiliary power supply (3) is input, and which converts the input AC voltage into a DC voltage and outputs the DC voltage; a DC-AC converter (21) that converts the output voltage of the AC-DC converter into an AC voltage; When two terminals of the auxiliary power supply from which an AC voltage is output are a first output terminal (3a) and a second output terminal (3b), a first input side switch (12a) and a second input side switch (12b) are arranged between the first output terminal and the first input terminal and are connected in series; a third input-side switch (12c) and a fourth input-side switch (12d) that are connected in series and are disposed between the second output terminal and the second input terminal; a first control section (13a); a second control section (26a), outputting an output voltage of either the auxiliary power supply or the system power supply (2) to an electrical load (6); when the first control unit receives from the second control unit a power supply permission notification indicating that power supply from the auxiliary power supply to the electric load is permitted and determines that the first input side switch, the second input side switch, the third input side switch, and the fourth input side switch are all normal, the second control unit controls the DC-AC converter to convert an output voltage of the AC-DC converter into an AC voltage and output the AC voltage to the electric load, The first control unit sends the power supply permission notice to the 2 When the control unit receives the fault signal and determines that at least one of the first input side switch, the second input side switch, the third input side switch, and the fourth input side switch is faulty, the control unit turns off the first input side switch, the second input side switch, the third input side switch, and the fourth input side switch, respectively, to prohibit power supply from the auxiliary power supply to the electrical load.

[0010] Therefore, it is possible to provide a power supply system that prohibits the auxiliary power supply from supplying power to the electrical load when the relay switch fails.

[0011] In the invention described in claim 2, in the power supply system, an AC / DC converter (11) having a first output terminal (11c) and a second output terminal (11d), which converts an AC voltage output from an auxiliary power supply (3) into a DC voltage and outputs the DC voltage from the first output terminal and the second output terminal; a DC-AC converter (21) having a first input terminal (21a) and a second input terminal (21b), and converting an output voltage of the AC-DC converter applied to the first input terminal and the second input terminal into an AC voltage; a first input-side switch (12a) and a second input-side switch (12b) that are connected in series and are disposed between the first output terminal and the first input terminal; a third input-side switch (12c) and a fourth input-side switch (12d) that are connected in series and are disposed between the second output terminal and the second input terminal; a first control section (13a); a second control section (26a), outputting an output voltage of either the auxiliary power supply or the system power supply (2) to an electrical load (6); when the first control unit receives from the second control unit a power supply permission notification indicating that power supply from the auxiliary power supply to the electric load is permitted and determines that the first input side switch, the second input side switch, the third input side switch, and the fourth input side switch are all normal, the second control unit controls the DC-AC converter to convert an output voltage of the AC-DC converter into an AC voltage and output the AC voltage to the electric load, The first control unit sends the power supply permission notice to the 2 When the control unit receives the fault signal and determines that at least one of the first input side switch, the second input side switch, the third input side switch, and the fourth input side switch is faulty, the control unit turns off the first input side switch, the second input side switch, the third input side switch, and the fourth input side switch, respectively, to prohibit power supply from the auxiliary power supply to the electrical load.

[0012] Therefore, it is possible to provide a power supply system that prohibits the auxiliary power supply from supplying power to the electrical load when the relay switch fails.

[0013] The reference symbols in parentheses attached to each component indicate an example of the correspondence between the component and the specific components described in the embodiments described below. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 2 is a block diagram showing the electrical circuit configuration of the power supply system in the first embodiment, and is a diagram for assisting in the detailed description of the electrical circuit configurations of the auxiliary input unit and the power conditioner. [Figure 2] 3 is a flowchart showing a power supply control process executed by a control unit of the power conditioner in the first embodiment of FIG. [Figure 3] 4 is a flowchart showing a storage battery power supply control process executed by a control unit of the power conditioner in the first embodiment of FIG. [Figure 4]3 is a flowchart showing a grid-connected operation control process executed by a control unit of the power conditioner in the first embodiment of FIG. [Figure 5] FIG. 10 is a diagram for assisting in the explanation of relay switch failure determination executed by the control unit of the auxiliary input unit of the first embodiment of FIG. 1, and is a diagram showing a state in which the four relay switches are normal, the input side relay switch is on, and the output side relay switch is off. [Figure 6] 1A is a voltage waveform diagram showing the waveform of the instantaneous value of the input voltage of the relay unit of the auxiliary input unit of the first embodiment of FIG. 1; FIG. 1B is a voltage waveform diagram showing the waveform of the instantaneous value of the output voltage of the relay unit of the auxiliary input unit of the first embodiment of FIG. 1; [Figure 7] FIG. 10 is a diagram for assisting in the explanation of the fault determination of the relay switch executed by the control unit of the auxiliary input unit of the first embodiment of FIG. 1, and is a diagram showing a state in which the input side relay switch is on and one of the output side relay switches is on due to a fault. [Figure 8] 1A is a voltage waveform diagram showing the waveform of the instantaneous value of the input voltage of the relay unit of the auxiliary input unit of the first embodiment of FIG. 1; FIG. 1B is a voltage waveform diagram showing the waveform of the instantaneous value of the output voltage of the relay unit of the auxiliary input unit of the first embodiment of FIG. 1; [Figure 9] FIG. 10 is a diagram for assisting in explaining the fault determination of the relay switches executed by the control unit of the auxiliary input unit of the first embodiment of FIG. 1, and shows a state in which four relay switches are normal and four relay switches are on. [Figure 10] 1A is a voltage waveform diagram showing the waveform of the instantaneous value of the input voltage of the relay unit of the auxiliary input unit of the first embodiment of FIG. 1; FIG. 1B is a voltage waveform diagram showing the waveform of the instantaneous value of the output voltage of the relay unit of the auxiliary input unit of the first embodiment of FIG. 1; [Figure 11] FIG. 10 is a diagram for assisting in the explanation of the fault determination of the relay switches executed by the control unit of the auxiliary input unit of the first embodiment of FIG. 1, and is a diagram showing a state in which one of the input side relay switches is turned off due to a fault and the output side relay switch is turned on. [Figure 12] 3 is a flowchart showing an independent operation control process executed by a control unit of the power conditioner in the first embodiment of FIG. [Figure 13] 10 is a flowchart showing a part of a relay control process executed by a control unit of the auxiliary input unit in the first embodiment of FIG. [Figure 14] 10 is a flowchart showing the rest of the relay control process executed by the control unit of the auxiliary input unit in the first embodiment of FIG. [Figure 15] 10 is a timing chart showing the execution timing of an input side relay welding determination process, an output side relay welding determination process, and a relay OFF failure determination process executed by a control unit of the auxiliary input unit in the first embodiment of FIG. [Figure 16] 1. FIG. 4 is a diagram showing the relationship between the input voltage, input-side voltage, output-side voltage, and voltage difference of the relay unit when the relay switch is normal in the auxiliary input unit in the first embodiment of FIG. [Figure 17] 1. FIG. 4 is a diagram showing the relationship between the input voltage, input-side voltage, output-side voltage, and voltage difference of the relay unit when a relay switch fails in the auxiliary input unit in the first embodiment of FIG. [Figure 18] FIG. 10 is a block diagram showing an electrical circuit configuration of a power supply system according to a second embodiment, and is a diagram for assisting in explaining the details of the configurations of an auxiliary input unit and a power conditioner. [Figure 19] FIG. 10 is a diagram for assisting in the explanation of relay switch failure determination executed by the control unit of the auxiliary input unit of the second embodiment, and is a diagram showing a state in which the four relay switches are normal, the input side relay switch is on, and the output side relay switch is off. [Figure 20] FIG. 10 is a diagram for assisting in the explanation of the fault determination of the relay switch executed by the control unit of the auxiliary input unit in the second embodiment, showing a state in which the input side relay switch is normally turned on and the output side relay switch is turned on due to a fault. [Figure 21]FIG. 10 is a diagram for assisting in the explanation of the fault determination of the relay switches executed by the control unit of the auxiliary input unit in the second embodiment, showing a state in which the four relay switches are normally on. [Figure 22] FIG. 10 is a diagram for assisting in the explanation of relay switch failure determination executed by the control unit of the auxiliary input unit in the second embodiment, showing a state in which one of the input side relay switches is turned off due to a failure and the output side relay switch is turned on normally. DETAILED DESCRIPTION OF THE INVENTION

[0015] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following embodiments, identical or equivalent parts are denoted by the same reference numerals in the drawings to simplify the description.

[0016] (First embodiment) 1 shows a power supply system 1 according to the first embodiment. The power supply system 1 according to the present embodiment supplies output power from at least one of a power system 2, an auxiliary power supply 3, a solar cell 4, and a storage battery 5 to an electrical load 6 in a home (i.e., an electrical load). Specifically, the power supply system 1 includes a standby input unit 10 and a power conditioner 20, as shown in FIG.

[0017] The auxiliary input unit 10 includes an AC-DC converter 11, a relay unit 12, a control unit 13, and voltage measurement circuits 14a and 14b. The AC-DC converter 11 converts the AC voltage output from the output terminals 3a and 3b of the auxiliary power supply 3 into a DC voltage.

[0018] Specifically, AC / DC converter 11 constitutes a full-wave rectifier circuit that outputs a DC voltage by full-wave rectifying the AC voltage output from auxiliary power supply 3. In FIG. 1, AC / DC converter 11 is abbreviated as AC / DC.

[0019] Here, the auxiliary power supply 3 is a first auxiliary power supply that generates an AC voltage. As the auxiliary power supply 3, an AC power supply device built into the automobile, a portable storage battery, a portable generator, or the like can be used. Two output terminals of the auxiliary power supply 3 that output AC voltage are referred to as output terminals 3a and 3b. Two input terminals of the AC-DC converter 11 to which the output voltage of the auxiliary power supply 3 is input are referred to as input terminals 11a and 11b. Input terminal 11a corresponds to the first input terminal. Input terminal 11b corresponds to the second input terminal.

[0020] Relay unit 12 includes relay switches 12a, 12b, 12c, and 12d. Relay switches 12a and 12b are connected in series between output terminal 3a of auxiliary power supply 3 and input terminal 11a of AC-DC converter 11. Relay switch 12a is located on the output terminal 3a side of auxiliary power supply 3 with respect to relay switch 12b.

[0021] Relay switches 12c and 12d are connected in series between output terminal 3b of auxiliary power supply 3 and input terminal 11b of AC-DC converter 11. Relay switch 12c is arranged on the output terminal 3b side of auxiliary power supply 3 with respect to relay switch 12d.

[0022] Relay switch 12a connects or disconnects output terminal 3a of auxiliary power supply 3 and relay switch 12b by being turned on or off. Relay switch 12b connects or disconnects input terminal 11a of AC-DC converter 11 and relay switch 12a by being turned on or off.

[0023] Relay switch 12c connects or disconnects output terminal 3b of auxiliary power supply 3 and relay switch 12d depending on whether it is on or off. Relay switch 12d connects or disconnects input terminal 11b of AC-DC converter 11 and relay switch 12c depending on whether it is on or off.

[0024] The relay switch 12a constitutes a first input side switch, the relay switch 12b constitutes a second input side switch, the relay switch 12c constitutes a third input side switch, and the relay switch 12d constitutes a fourth input side switch. Hereinafter, for convenience of explanation, the relay switch 12a and the relay switch 12c will also be collectively referred to as the input side relay switches 12a and 12c, and the relay switch 12b and the relay switch 12d will also be collectively referred to as the output side relay switches 12b and 12d.

[0025] The control unit 13 includes a control unit 13a and a communication processing unit 13b. The control unit 13a is a first control unit that includes a microcomputer, a memory, etc. The control unit 13a executes relay unit control processing according to a computer program that is pre-stored in the memory.

[0026] When executing the relay unit control process, the control unit 13a controls the relay switches 12a, 12b, 12c, and 12d of the relay unit 12 based on the detected values ​​of the voltage measurement circuits 14a and 14b. The communication processing unit 13b is controlled by the control unit 13a and communicates with the communication processing unit 26b of the control unit 26 via a communication line.

[0027] The voltage measuring circuit 14 a detects the instantaneous value Vin of the AC voltage applied from the output terminals 3 a and 3 b of the auxiliary power supply 3 to the relay switches 12 a , 12 b , 12 c and 12 d of the relay unit 12 .

[0028] The voltage measuring circuit 14b detects the instantaneous value Vout of the AC voltage output from the relay switches 12a, 12b, 12c, and 12d of the relay unit 12 to the input terminals 11a and 11b of the AC-DC converter 11.

[0029] The input terminals 11 a and 11 b are input terminals to which AC voltages are applied from the relay switches 12 a, 12 b, 12 c, and 12 d of the relay unit 12 in the AC-DC converter 11 .

[0030] Input terminal 11a is connected to output terminal 3a of auxiliary power supply 3 via relay switches 12a and 12b. Input terminal 11b is connected to output terminal 3b of auxiliary power supply 3 via relay switches 12c and 12d.

[0031] The power conditioner 20 in FIG. 1 includes an inverter circuit 21, DC / DC converters 22, 23, and 24, a system-side relay unit 25, and a control unit .

[0032] The inverter circuit 21 is an H-bridge circuit including four switching elements. The inverter circuit 21 is controlled by a control unit 26a of a control unit 26, and converts the output voltage of the DC / DC converter 22 into an AC voltage by switching the four switching elements, and outputs the AC voltage to the electric loads 6 in the house.

[0033] The inverter circuit 21 of this embodiment outputs an AC voltage with an effective value of, for example, single-phase 100 V. The inverter circuit 21 constitutes a DC-AC converter.

[0034] The residential electrical loads 6 are electrical appliances such as refrigerators, air conditioners, and lighting equipment that are installed in the home.

[0035] The two input terminals of the residential electrical load 6 are connected to the output terminals 21c and 21d of the inverter circuit 21. The residential electrical load 6 is connected to the grid power supply 2 via a grid-side relay unit 25. The residential electrical load 6 receives power from the inverter circuit 21 and the grid power supply 2, as will be described later.

[0036] The DC / DC converter 22 is controlled by the control section 26 a of the control unit 26 , and boosts the output voltage of the AC / DC converter 11 of the auxiliary input unit 10 and outputs the boosted voltage to the inverter circuit 21 .

[0037] The DC / DC converter 23 is controlled by a control section 26a of the control unit 26, and boosts the output voltage of the solar cell 4 and outputs it to the inverter circuit 21. The solar cell 4 is a power generation device that generates DC power using sunlight.

[0038] DC / DC converter 24 is controlled by control section 26a of control unit 26, and boosts the output voltage of storage battery 5 and outputs it to inverter circuit 21. DC / DC converter 24 is controlled by control section 26a of control unit 26, and boosts (or lowers) the output voltage of DC / DC converters 22, 23 and outputs it to storage battery 5. DC / DC converters 23, 24 correspond to auxiliary power converters.

[0039] As a result, the storage battery 5 stores the power output from the solar cell 4 and the auxiliary input unit 10. The storage battery 5 is composed of a secondary battery, a capacitor, etc., and stores DC power. The storage battery 5 and the solar cell 4 each constitute a second auxiliary power source.

[0040] The two output terminals of the DC / DC converter 22 are connected to the input terminals 21a and 21b of the inverter circuit 21. The two output terminals of the DC / DC converter 23 are connected to the input terminals 21a and 21b of the inverter circuit 21.

[0041] The two output terminals of the DC / DC converter 24 are connected to the input terminals 21a and 21b of the inverter circuit 21. Here, the input terminal 21a of the inverter circuit 21 corresponds to the first input terminal, and the input terminal 21b corresponds to the second input terminal.

[0042] The system-side relay unit 25 includes relay switches (i.e., output-side switches) 25a and 25b. The relay switch 25a is connected between one of the two input terminals of the domestic electrical load 6 and the output terminal 2a of the system power supply 2. The relay switch 25b is connected between the other of the two input terminals of the domestic electrical load 6 and the output terminal 2b of the system power supply 2.

[0043] The relay switches 25a and 25b connect or disconnect the inverter circuit 21, the residential electrical load 6, and the system power supply 2 by turning them on or off.

[0044] The control unit 26 includes a control unit 26a and a communication processing unit 26b. The control unit 26a is a second control unit that includes a microcomputer, a memory, etc. The control unit 26a executes the autonomous operation control process according to a computer program that is pre-stored in the memory.

[0045] When executing the independent operation control process, the control unit 26a controls the inverter circuit 21, the DC / DC converters 22, 23, 24, and the relay switches 25a and 25b of the grid-side relay unit 25. The communication processing unit 26b is controlled by the control unit 26a and communicates with the communication processing unit 13b of the control unit 13 via a communication line.

[0046] The auxiliary input unit 10 and the power conditioner 20 of this embodiment each have an independent housing.

[0047] Next, the operation of the power supply system 1 of this embodiment will be described.

[0048] The control unit 26a controls the inverter circuit 21, DC / DC converters 22, 23, 24, and system-side relay unit 25 to supply power output from the system power supply 2, auxiliary power supply 3, solar cell 4, and storage battery 5 to the electrical loads 6 in the home.

[0049] For example, when the output power of the solar cell 4 is to be supplied to the electric load 6 in the house, the control unit 26a executes the power supply control process according to the flowchart of FIG.

[0050] That is, the control unit 26a starts the operation of the DC / DC converter 23 and the inverter circuit 21 in step S50.

[0051] Therefore, the DC / DC converter 23 boosts the output voltage of the solar cell 4 and outputs it to the inverter circuit 21. The inverter circuit 21 converts the output voltage of the DC / DC converter 23 into an AC voltage and outputs it to the domestic electrical loads 6. Therefore, the domestic electrical loads 6 are operated by the output power of the solar cell 4.

[0052] When the output power of the storage battery 5 is to be supplied to the in-house electrical load 6, the control unit 26a executes a storage battery power supply control process according to the flowchart of FIG.

[0053] That is, in step S51, the control unit 26a starts the operation of the DC / DC converter 24 and the inverter circuit 21.

[0054] Therefore, the DC / DC converter 24 boosts the output voltage of the storage battery 5 and outputs it to the inverter circuit 21. The inverter circuit 21 converts the output voltage of the DC / DC converter 23 into an AC voltage and outputs it to the home electrical loads 6. Therefore, the home electrical loads 6 are operated by the output power of the storage battery 5.

[0055] Furthermore, when the output power of the system power supply 2 is to be supplied to the residential electrical load 6, the control unit 26a executes the grid-connected operation control process according to the flowchart of FIG.

[0056] That is, in step S52, the control unit 26a turns on the relay switches 25a and 25b of the system-side relay unit 25. Therefore, when the relay switches 25a and 25b are turned on, the system power supply 2 is connected to the domestic electric loads 6. Therefore, the domestic electric loads 6 are operated by the output power of the system power supply 2.

[0057] At this time, DC / DC converter 22 is stopped, and therefore, the supply of power output from auxiliary power supply 3 to electrical loads 6 in the house is stopped.

[0058] Furthermore, when the output power of the auxiliary power source 3 is to be supplied to the domestic electrical loads 6 due to a power outage or the like, the control unit 26a executes an independent operation control process. In conjunction with this, the control unit 13a executes a relay control process. The relay control process is a process that includes a failure determination for the relay switches 12a, 12b, 12c, and 12d.

[0059] Therefore, before describing the independent operation control process and the relay control process, the principles (1), (2), and (3) of determining whether or not there is a failure in the relay switches 12a, 12b, 12c, and 12d will be described below with reference to FIGS. (1) The principle of failure determination when the control section 13a of the auxiliary input unit 10 turns on the input side relay switches 12a and 12c and turns off the output side relay switches 12b and 12d will be described with reference to FIGS.

[0060] (1-1) When the relay switches 12a, 12b, 12c, and 12d are normal, the following occurs.

[0061] 5, when relay switch 12a is turned on, it connects output terminal 3a of auxiliary power supply 3 to relay switch 12b. When relay switch 12b is turned off, it opens connection between relay switch 12a and input terminal 11a of AC-DC converter 11.

[0062] When relay switch 12c is turned on, it connects output terminal 3b of auxiliary power supply 3 to relay switch 12d. When relay switch 12d is turned off, it opens connection between relay switch 12c and input terminal 11b of AC-DC converter 11.

[0063] In this case, the instantaneous value Vin of the input voltage has a sinusoidal waveform, as shown in Fig. 6(a). Fig. 6(a) is a voltage waveform diagram in which the vertical axis represents the instantaneous value Vin of the input voltage and the horizontal axis represents time. The instantaneous value Vout of the output voltage becomes zero volts, as shown in Fig. 6(b). Therefore, the effective value of the AC voltage output from the relay unit 12 to the AC-DC converter 11 becomes zero. Fig. 6(b) is a voltage waveform diagram in which the vertical axis represents the instantaneous value Vout of the output voltage and the horizontal axis represents time.

[0064] (1-2) As shown in Figure 7, if relay switches 12a, 12c, and 12d are normal and relay switch 12b is turned on due to a failure caused by welding, the following occurs. Figure 7 shows a state in which, of relay switches 12a, 12b, 12c, and 12d, only relay switch 12b is turned on due to a failure caused by welding. The dashed line in Figure 7 shows the case in which relay switch 12b is normal.

[0065] That is, when relay switch 12a is turned on, it connects output terminal 3a of auxiliary power supply 3 with relay switch 12b. When relay switch 12b is turned on, it connects relay switch 12a with input terminal 11a of AC-DC converter 11.

[0066] When relay switch 12c is turned on, it connects output terminal 3b of auxiliary power supply 3 to relay switch 12d. When relay switch 12d is turned off, it opens connection between relay switch 12c and input terminal 11b of AC-DC converter 11.

[0067] In this case, the instantaneous value Vin of the input voltage has a sinusoidal waveform as shown in FIG. 8(a). FIG. 8(a) is a voltage waveform diagram in which the vertical axis represents the instantaneous value Vin of the input voltage and the horizontal axis represents time. As shown in FIG. 8(b), the instantaneous value Vout of the output voltage has a half-wave rectified waveform. FIG. 8(b) is a voltage waveform diagram in which the vertical axis represents the instantaneous value Vout of the output voltage and the horizontal axis represents time. Therefore, the effective value of the AC voltage output from relay unit 12 to AC-DC converter 11 becomes a positive value greater than zero.

[0068] (1-3) When the relay switches 12a, 12b, and 12c are normally turned off and the relay switch 12d is turned on due to a welding failure, the following occurs.

[0069] In this case, as in (1-2) above, the instantaneous value Vin of the input voltage has a sinusoidal waveform as shown in Fig. 8(a), and the instantaneous value Vout of the output voltage has a half-wave rectified waveform as shown in Fig. 8(b).

[0070] Therefore, the effective value of the output voltage output from the relay unit 12 to the AC-DC converter 11 becomes a positive value greater than zero.

[0071] As described above, the control unit 13a uses a threshold value greater than zero and determines whether the output voltage is equal to or greater than the threshold value, thereby determining whether one of the relay switches 12b and 12d is faulty. (2) The principle of fault determination when the control section 13a of the auxiliary input unit 10 turns off the relay switches 12a and 12c and turns on the relay switches 12b and 12d will be described.

[0072] (2-1) When the relay switches 12a, 12b, 12c, and 12d are normal, the following occurs.

[0073] That is, when relay switch 12a is turned off, it opens the gap between output terminal 3a of auxiliary power supply 3 and relay switch 12b. When relay switch 12b is turned on, it connects relay switch 12a and input terminal 11a of AC-DC converter 11.

[0074] When relay switch 12c is turned off, it disconnects output terminal 3b of auxiliary power supply 3 from relay switch 12d. When relay switch 12d is turned on, it connects relay switch 12c and input terminal 11b of AC-DC converter 11.

[0075] In this case, the instantaneous value of the input voltage Vin has a sinusoidal waveform as shown in Figure 6(a), and the instantaneous value of the output voltage Vout becomes zero volts as shown in Figure 6(b). Therefore, the effective value of the output voltage of the relay unit 12 becomes zero. (2-2) When the relay switches 12b, 12c, and 12d are normal and the relay switch 12a is turned on due to a welding failure, the following occurs.

[0076] That is, when relay switch 12a is turned on, it connects output terminal 3a of auxiliary power supply 3 with relay switch 12b. When relay switch 12b is turned on, it connects relay switch 12a with input terminal 11a of AC-DC converter 11.

[0077] When relay switch 12c is turned off, it disconnects output terminal 3b of auxiliary power supply 3 from relay switch 12d. When relay switch 12d is turned on, it connects relay switch 12c and input terminal 11b of AC-DC converter 11.

[0078] In this case, as in (1-2) above, the instantaneous value Vin of the input voltage has a sinusoidal waveform as shown in Figure 8(a). The instantaneous value Vout of the output voltage has a half-wave rectified waveform as shown in Figure 8(b). Therefore, the effective value of the output voltage is a positive value greater than zero. (2-3) When the relay switches 12a, 12b, and 12d are normal and the relay switch 12c is turned on due to a welding failure, the following occurs.

[0079] In this case, as in (1-2) above, the instantaneous value Vin of the input voltage has a sinusoidal waveform as shown in Fig. 8(a). The instantaneous value Vout of the output voltage has a half-wave rectified waveform as shown in Fig. 8(b). Therefore, the effective value of the output voltage of the relay unit 12 becomes a positive value greater than zero.

[0080] As described above, the control unit 13a of the auxiliary input unit 10 uses a threshold value greater than zero and determines whether the output side voltage is greater than or equal to the threshold value, thereby determining whether one of the relay switches 12a and 12c is faulty.

[0081] (3) The principle of fault determination when the control unit of the auxiliary input unit turns on each of the relay switches 12a, 12b, 12c, and 12d will be described. (3-1) When the relay switches 12a, 12b, 12c, and 12d are normal, the following occurs.

[0082] In this case, the instantaneous value Vin of the input voltage has a sinusoidal waveform as shown in FIG. 10(a). FIG. 10(a) is a voltage waveform diagram in which the vertical axis represents the instantaneous value Vin of the input voltage and the horizontal axis represents time. As shown in FIG. 10(b), the instantaneous value Vout of the output voltage has a sinusoidal waveform. FIG. 10(b) is a voltage waveform diagram in which the vertical axis represents the instantaneous value Vout of the output voltage and the horizontal axis represents time. Therefore, the effective value of the output voltage of the relay unit 12 becomes a positive value greater than zero. (3-2) As shown in Figure 11, if only one of the relay switches 12a, 12b, 12c, and 12d fails and is turned off, the following occurs. Figure 11 shows a state in which only one of the relay switches 12a, 12b, 12c, and 12d, the relay switch 12a, fails and is turned off. The dashed line in Figure 11 shows the case in which the relay switch 12a is normal.

[0083] In this case, the instantaneous value Vout of the input voltage has a full-wave rectified waveform as shown in Fig. 8(a), and the instantaneous value Vout of the output voltage has a half-wave rectified waveform as shown in Fig. 8(b).

[0084] For ease of explanation, the effective value of the output voltage of relay unit 12 output from relay unit 12 to AC / DC converter 11 is referred to as output-side voltage. The effective value of the input voltage of relay unit 12 input from auxiliary power supply 3 to relay unit 12 is referred to as input-side voltage.

[0085] As a result of the above, the control unit 13a obtains a subtraction value ΔV by subtracting the effective value of the output voltage of the relay unit 12 (ie, the output side voltage) from the effective value of the input voltage of the relay unit 12 (ie, the input side voltage).

[0086] The control unit 13a determines whether or not the calculated subtraction value ΔV is equal to or greater than a threshold value, thereby determining whether or not any one of the relay switches 12a, 12b, 12c, and 12d is faulty.

[0087] Next, the details of the independent operation control process in the control unit 26a and the relay control process in the control unit 13a will be described with reference to FIGS.

[0088] First, the control unit 26a repeatedly executes the independent operation control process according to the flowchart in Fig. 12. The control unit 13a, in conjunction with the control unit 26a, repeatedly executes the relay control process according to the flowcharts in Figs.

[0089] First, in step S100 of Fig. 12, control unit 26a transmits a power supply permission notice from communication processing unit 26b to control unit 13a through communication processing unit 13b. The power supply permission notice is instruction information for notifying auxiliary input unit 10 that it is permitted to start supplying power from auxiliary power supply 3 to in-house electrical loads 6.

[0090] 13, the control unit 13a determines whether or not a power supply permission notice has been received from the control unit 26a via the communication processing units 26b and 13b. This determines whether or not the control unit 26a has given permission to start power supply from the auxiliary power supply 3 to the domestic electrical loads 6.

[0091] At this time, if the control unit 13a has not received a power supply permission notice from the control unit 26a, the control unit 13a determines NO in step S200. That is, the control unit 13a determines that the control unit 26a has not permitted the auxiliary power supply 3 to start supplying power to the domestic electrical loads 6. In this case, the control unit 13a performs the following in step S200a: All of the relay switches 12a, 12b, 12c, and 12d of the relay unit 12 are turned off to terminate the execution of the relay control process.

[0092] Furthermore, when the control unit 13a receives a power supply permission notification from the control unit 26a, the control unit 13a determines YES in step S200. As a result, it is determined that the control unit 26a has permitted the auxiliary power supply 3 to start supplying power to the domestic electrical loads 6.

[0093] Next, in steps S210 to S310, the control unit 13a determines whether or not the relay switches 12a, 12b, 12c, and 12d of the relay unit 12 are malfunctioning.

[0094] Specifically, in step S210, the control unit 13a turns off the input side relay switches 12a and 12c and turns on the output side relay switches 12b and 12d.

[0095] Accordingly, in step S220, the control unit 13a calculates the output voltage (that is, the effective value of the output voltage of the relay unit 12) based on the detected value of the voltage measurement circuit 14b.

[0096] Next, in step S230, the control unit 13a determines whether the output voltage is equal to or greater than a threshold value, which is a predetermined value greater than zero.

[0097] At this time, if the output voltage is equal to or greater than the threshold value, the control unit 13a determines YES in step S230.

[0098] In this case, the control unit 13a determines that only one of the relay switches 12a and 12c has failed due to welding or the like and is in the ON state.

[0099] Accordingly, in step S270, the control unit 13a prohibits the auxiliary power supply 3 from supplying power to the electric loads 6 in the house by turning off all of the relay switches 12a, 12b, 12c, and 12d.

[0100] Accordingly, in step S280, the control unit 13a transmits an abnormality notification of the relay unit 12 from the communication processing unit 13b to the control unit 26a via the communication processing unit 26b, and ends the execution of the relay control process. The abnormality notification is information indicating that only one of the input side relay switches 12a, 12c has failed due to welding or the like and is in the ON state.

[0101] Furthermore, when the output voltage is less than the threshold value, the control unit 13a determines NO in step S230.

[0102] Next, in step S240, the control unit 13a turns on the input side relay switches 12a and 12c and turns off the output side relay switches 12b and 12d.

[0103] Accordingly, in step S250, the control unit 13a calculates the output voltage (that is, the effective value of the output voltage of the relay unit 12) based on the detected value of the voltage measurement circuit 14b.

[0104] Next, in step S260, the control unit 13a determines whether the output voltage is equal to or greater than a threshold value, which is a predetermined value greater than zero.

[0105] At this time, if the output voltage is equal to or greater than the threshold value, the control unit 13a determines YES in step S260.

[0106] In this case, the control unit 13a determines that only one of the output-side relay switches 12b and 12d has failed due to welding or the like and is in the ON state.

[0107] Accordingly, in step S270, the control unit 13a prohibits the auxiliary power supply 3 from supplying power to the electric loads 6 in the house by turning off all of the relay switches 12a, 12b, 12c, and 12d.

[0108] Accordingly, in step S280, the control unit 13a transmits a notification of an abnormality in the relay unit 12 from the communication processing unit 13b to the control unit 26a via the communication processing unit 26b.

[0109] When the output voltage is less than the threshold value, the control unit 13a determines NO in step S260.

[0110] Next, in step S290, the control unit 13a turns on all of the relay switches 12a, 12b, 12c, and 12d.

[0111] Accordingly, in step S300, the control unit 13a calculates the output voltage based on the detected value of the voltage measurement circuit 14b, and in step S300, the control unit 13a calculates the input voltage based on the detected value of the voltage measurement circuit 14a.

[0112] Accordingly, in step S310, the control unit 13a calculates a subtraction value ΔV by subtracting the output voltage from the input voltage, and determines whether the subtraction value ΔV is equal to or greater than a threshold value. The threshold value is a predetermined value greater than zero.

[0113] At this time, if the subtraction value ΔV is equal to or greater than the threshold value, the control unit 13a determines YES in step S310. In this case, the control unit 13a determines that only one of the relay switches 12a, 12b, 12c, and 12d is in the OFF state due to a failure.

[0114] Accordingly, in step S330, the control unit 13a prohibits the auxiliary power supply 3 from supplying power to the domestic electrical loads 6 by turning off all of the relay switches 12a, 12b, 12c, and 12d.

[0115] Accordingly, in step S340, the control unit 13a transmits an abnormality notification of the relay unit 12 from the communication processing unit 13b to the control unit 26a via the communication processing unit 26b, and ends the execution of the relay control process. The abnormality notification is information for notifying that only one of the relay switches 12a, 12b, 12c, and 12d has failed and is in the OFF state.

[0116] Furthermore, in step S310, if the subtraction value ΔV is less than the threshold value, the control unit 13a determines that the result is NO. In this case, the control unit 13a determines that all of the relay switches 12a, 12b, 12c, and 12d are normal.

[0117] In this case, the output terminal 3a of the auxiliary power supply 3 and the input terminal 11a of the AC-DC converter 11 are connected, and the output terminal 3b of the auxiliary power supply 3 and the input terminal 11b of the AC-DC converter 11 are connected.

[0118] Accordingly, in step S320, the control unit 13a starts supplying power from the auxiliary power supply 3 to the in-house electrical loads 6. Specifically, the control unit 13a transmits a normality notification indicating that all of the relay switches 12a, 12b, 12c, and 12d are normal from the communication processing unit 13b to the control unit 26a via the communication processing unit 26b, and ends the execution of the relay control process.

[0119] Furthermore, in step S110 of FIG. 12, the control unit 26a determines whether or not an abnormality notification has been received from the communication processing unit 13b via the communication processing unit 26b.

[0120] At this time, when control unit 26a receives the abnormality notification from communication processing unit 13b, it determines YES in step S110. Accordingly, control unit 26a prohibits transmission of a power supply permission notification to control unit 13a in step S120. As a result, power supply from auxiliary power supply 3 to household electrical loads 6 is prohibited.

[0121] Furthermore, when the control unit 26a does not receive an abnormality notification from the communication processing unit 13b, the determination in step S110 is NO.

[0122] Next, in step S130, the control unit 26a determines whether or not a normality notification of the relay unit 12 has been received from the communication processing unit 13b via the communication processing unit 26b.

[0123] At this time, when the control unit 26a receives a normal notification from the communication processing unit 13b, the determination in step S130 is YES.

[0124] Accordingly, in step S140, the control unit 26a turns off the relay switches 25a and 25b of the system-side relay unit 25, and starts the operation of the inverter circuit 21 and the DC / DC converter 22.

[0125] At this time, AC / DC converter 11 converts the output voltage of auxiliary power supply 3 into a DC voltage. DC / DC converter 22 boosts the output voltage of AC / DC converter 11. Inverter circuit 21 converts the output voltage of DC / DC converter 22 into an AC voltage and outputs it to domestic electrical loads 6. As a result, domestic electrical loads 6 operate based on the output power of auxiliary power supply 3.

[0126] Next, the timing of the control unit 13a's failure determination of the relay unit 12 in this embodiment will be described with reference to FIGS. 15(a), 15(b), and 15(c).

[0127] Fig. 15(a) is a timing chart showing the timing when the control unit 13a receives a power supply permission notification. Fig. 15(b) is a timing chart showing the timing when the control unit 13a issues an on / off instruction to the input side relay switches 12a and 12c. Fig. 15(c) is a timing chart showing the timing when the control unit 13a issues an on / off instruction to the output side relay switches 12b and 12d.

[0128] When the control unit 13a receives the power supply permission notification from the control unit 26a at timing t1, the control unit 13a turns on the output side relay switches 12b and 12d while keeping the input side relay switches 12a and 12c off.

[0129] After that, at timing t2, the control unit 13a starts executing the input side relay welding determination process of steps S210 to S230.

[0130] Next, at timing t3, the control unit 13a turns off the output side relay switches 12b and 12d, and accordingly, the control unit 13a ends the execution of the input side relay welding determination process of steps S210 to S230.

[0131] Next, at timing t4, the control unit 13a turns on the input side relay switches 12a and 12c while keeping the output side relay switches 12b and 12d off.

[0132] After that, at timing t5, the control unit 13a starts executing the output side relay welding determination process of steps S240 to S260.

[0133] Next, at timing t6, the control unit 13a turns off the input side relay switches 12a and 12c, and accordingly, the control unit 13a ends the execution of the output side relay welding determination process of steps S240 to S260.

[0134] Next, at timing t7, the control unit 13a turns on the input side relay switches 12a and 12c and the output side relay switches 12b and 12d.

[0135] After that, at timing t8, the control unit 13a starts executing the relay OFF failure determination process of steps S290 to S310.

[0136] At the next timing t9, the control unit 13a ends the execution of the relay OFF failure determination process of steps S290 to S310.

[0137] The time interval between timing t1 and timing t2 is the delay time required for output-side relay switches 12b and 12d to turn on. The time interval between timing t4 and timing t5 is the delay time required for input-side relay switches 12a and 12c to turn on. The time interval between timing t7 and timing t8 is the delay time required for input-side relay switches 12a and 12c and output-side relay switches 12b and 12d to turn on.

[0138] According to the present embodiment described above, the power supply system 1 has input terminals 11a, 11b to which the AC voltage output from the auxiliary power supply 3 is input, and includes an AC-DC converter 11 that converts the input AC voltage into a DC voltage and outputs it.

[0139] The power supply system 1 includes an inverter circuit 21 that converts the output voltage provided from the AC-DC converter 11 through a DC / DC converter 22 into an AC voltage. The power supply system 1 includes relay switches 12a and 12c that are arranged between an output terminal 3a of the auxiliary power supply 3 and an input terminal 11a of the AC-DC converter 11 and are connected in series.

[0140] The power supply system 1 includes relay switches 12b and 12d connected in series and disposed between an output terminal 3b of the auxiliary power supply 3 and an input terminal 11b of the AC-DC converter 11. The power supply system 1 outputs the output voltage of only one of the auxiliary power supply 3 and the system power supply 2 to the electrical load 6 in the house.

[0141] When control unit 13a receives the power supply permission notification from control unit 26a and determines that relay switches 12a, 12b, 12c, and 12d are normal, control unit 26a controls inverter circuit 21. Therefore, inverter circuit 21 converts the output voltage provided from AC-DC converter 11 through DC / DC converter 22 into an AC voltage and outputs it to electrical loads 6 in the house.

[0142] When the control unit 13a receives the power supply permission notification from the control unit 26a and determines that at least one of the relay switches 12a, 12b, 12c, and 12d is faulty, the control unit 13a turns off all of the relay switches 12a, 12b, 12c, and 12d. As a result, the control unit 13a prohibits the auxiliary power supply 3 from supplying power to the electric loads 6 in the house.

[0143] As described above, it is possible to provide the power supply system 1 that prohibits the auxiliary power supply 3 from supplying power to the electric loads 6 in the house when the relay switches 12a, 12b, 12c, and 12d fail.

[0144] The power supply system 1 of this embodiment configured as above can achieve the following operational effects (a), (b), and (c). (a) Inverter circuit 21 converts the output voltages of DC / DC converters 22, 23, and 24 into AC voltage and outputs it to the electrical loads 6 in the house. DC / DC converter 23 boosts the output voltage of solar cell 4 and outputs it to inverter circuit 21. DC / DC converter 24 boosts the output voltage of storage battery 5 and outputs it to inverter circuit 21.

[0145] Therefore, even if the supply of power from the auxiliary power source 3 to the electrical loads 6 in the home is prohibited, the output voltage of the solar cell 4 and the storage battery 5 can be converted to AC voltage by the inverter circuit 21 and output to the electrical loads 6 in the home.

[0146] If the entire power supply system 1 is shut down when the relay unit 12 fails, the entire house will suffer a power outage. Restoring the power supply system 1 cannot be performed by a user's operation, but requires the work of a worker with specialized knowledge (i.e., a service technician), and it may take several days to complete the restoration.

[0147] In contrast to this, in this embodiment, when the relay unit 12 fails, it is possible to realize an operation in which the output power of the solar cell 4 and the storage battery 5 is supplied to the electric loads 6 in the house without shutting down the entire power supply system 1. Therefore, it is possible to prevent a power outage in the entire house.

[0148] As a result, even if relay switches 12a, 12b, 12c, and 12d fail, power supply system 1 can be provided that can supply power to electrical loads 6 in the house without shutting down the entire power supply system 1. (b) The control unit 13a determines that one of the input side relay switches 12a and 12c has a welding fault based on a YES determination in step S230, and determines that one of the output side relay switches 12b and 12d has a welding fault based on a YES determination in step S260.

[0149] The control unit 13a determines that one of the relay switches 12a, 12b, 12c, and 12d has failed and is in the OFF state, based on the YES determination in step S310.

[0150] In this way, the cause of the failure of the relay switches 12a, 12b, 12c, and 12d can be identified by the failure determination process by the control unit 13a, which leads to a reduction in the number of steps required to identify the problem. (c) Figure 16 shows the relationship between the input voltage, input side voltage, output side voltage, and voltage difference when the control unit 13a turns on the relay switches 12a, 12b, 12c, and 12d when the relay switches 12a, 12b, 12c, and 12d are normal.

[0151] FIG. 17 shows the relationship between the input voltage, input side voltage, output side voltage, and voltage difference when the control unit 13a turns on the relay switches 12a, 12b, 12c, and 12d, and one of the relay switches 12a, 12b, 12c, and 12d fails and is in the off state.

[0152] The input voltage is the effective value of the voltage input from the auxiliary power supply 3 to the standby input unit 10. The voltage difference is the difference obtained by subtracting the output voltage from the input voltage. The input voltage is the effective value of the input voltage of the relay unit 12. The output voltage is the effective value of the output voltage of the relay unit 12.

[0153] As shown in FIG. 16, when relay switches 12a, 12b, 12c, and 12d are normal, the voltage difference remains at zero volts even if the input voltage and output voltage fluctuate.

[0154] As shown in FIG. 17, when any of the relay switches 12a, 12b, 12c, and 12d has failed and is in the OFF state, the output voltage changes compared to when the relay switches 12a, 12b, 12c, and 12d are normal.

[0155] Here, although the voltage difference fluctuates when the input voltage and the output voltage fluctuate, the voltage difference is a value greater than zero.

[0156] In response to this, the control unit 13a determines whether any of the relay switches 12a, 12b, 12c, and 12d has failed and is in the OFF state by determining whether the subtraction value ΔV obtained by subtracting the output voltage from the input voltage is equal to or greater than a threshold value, thereby enabling accurate failure determination of the relay switches 12a, 12b, 12c, and 12d.

[0157] When the auxiliary power supply 3 is an AC power supply device built into the automobile or an external generator, or when the power lines between the auxiliary power supply 3 and the auxiliary input unit 10 are long, the effective value of the AC voltage input from the auxiliary power supply 3 to the auxiliary input unit 10 fluctuates. For this reason, as described above, using the subtraction value ΔV to determine whether or not there is a failure in the relay switches 12a, 12b, 12c, and 12d is effective in making a highly accurate determination.

[0158] (Second embodiment) In the first embodiment, an example has been described in which the relay unit 12 is connected between the auxiliary power supply 3 and the AC-DC converter 11. However, instead of this, a second embodiment in which the relay unit 12 is connected between the AC-DC converter 11 and the DC / DC converter 22 will be described with reference to Fig. 18 .

[0159] The main difference between this embodiment and the first embodiment is the arrangement of the relay unit 12 and the voltage measurement circuits 14a, 14b. Therefore, the following description will mainly focus on the arrangement of the relay unit 12 and the voltage measurement circuits 14a, 14b in this embodiment.

[0160] The relay unit 12 is connected between the AC-DC converter 11 and the inverter circuit 21. In other words, the relay unit 12 is connected between the AC-DC converter 11 and the DC / DC converter 22.

[0161] The relay switches 12a and 12b are arranged between the output terminal (ie, first output terminal) 11c of the AC-DC converter 11 and the input terminal 22a of the DC / DC converter 22 (ie, the input terminal 21a of the inverter circuit 21).

[0162] Relay switches 12c and 12d are arranged between output terminal 11d of AC / DC converter 11 (ie, second output terminal) and input terminal 22b of DC / DC converter 22 (ie, input terminal 21b of inverter circuit 21).

[0163] The voltage measurement circuit 14a detects an instantaneous value Vin of the input voltage of the relay unit 12, which is applied from the AC-DC converter 11 to the relay unit 12. The voltage measurement circuit 14b detects an instantaneous value Vout of the output voltage of the relay unit 12, which is output from the relay unit 12 to the DC / DC converter 22.

[0164] Next, the operation of the power supply system 1 of this embodiment will be described.

[0165] The control unit 26a executes the control processes shown in Figures 2, 3, 5, and 12, similarly to the first embodiment. The control unit 13a executes the relay control processes shown in Figures 13 and 14, similarly to the first embodiment.

[0166] Here, the present embodiment differs from the first embodiment in the principles of failure determination of relay switches 12a, 12b, 12c, and 12d in control unit 13a. Therefore, the principles (4), (5), and (6) of failure determination of relay switches 12a, 12b, 12c, and 12d in control unit 13a in the present embodiment will be described with reference to FIGS. 19 to 22 show the state of relay unit 12 arranged between AC / DC converter 11 and power conditioner 20. In Figs. 19 to 22, DC / DC converter 22 in power conditioner 20 is not shown. (4) The principle of failure determination when the control section 13a of the auxiliary input unit 10 turns on the input side relay switches 12a and 12c and turns off the output side relay switches 12b and 12d will be described with reference to FIG. (4-1) When the relay switches 12a, 12b, 12c, and 12d are normal, the following occurs.

[0167] 19, when relay switch 12a is turned on, it connects output terminal 11c of AC-DC converter 11 and relay switch 12b. When relay switch 12b is turned off, it opens connection between relay switch 12a and input terminal 22a of DC / DC converter 22.

[0168] When relay switch 12c is turned on, it connects output terminal 11c of AC-DC converter 11 and relay switch 12d. When relay switch 12d is turned off, it opens connection between relay switch 12c and input terminal 22b of DC / DC converter 22.

[0169] In this case, the instantaneous value of the input voltage Vin becomes a full-wave rectified waveform, and the instantaneous value of the output voltage Vout becomes zero volts. As a result, the effective value of the output voltage of the relay unit 12 becomes zero. (4-2) As shown in Figure 20, if relay switches 12a and 12c are normal and relay switches 12b and 12d are turned on due to a failure caused by welding, the following occurs. Figure 20 shows a state in which relay switches 12b and 12d are turned on due to a failure caused by welding. The dashed line in Figure 20 shows the case in which relay switches 12b and 12d are normal.

[0170] That is, when relay switch 12a is turned on, it connects output terminal 11c of AC-DC converter 11 to relay switch 12b. When relay switch 12b is turned on, it connects relay switch 12a to input terminal 22a of DC / DC converter 22.

[0171] When relay switch 12c is turned on, it connects output terminal 11c of AC-DC converter 11 to relay switch 12d. When relay switch 12d is turned on, it connects relay switch 12c to input terminal 22b of DC / DC converter 22.

[0172] In this case, the instantaneous value of the input voltage Vin has a full-wave rectified waveform, and the instantaneous value of the output voltage Vout also has a full-wave rectified waveform. As a result, the effective value of the output voltage of the relay unit 12 becomes a positive value greater than zero.

[0173] As described above, in step S260 of Fig. 13, the control unit 13a determines whether each of the relay switches 12b and 12d is turned on due to a fault by determining whether the output voltage is equal to or greater than the threshold value. The threshold value is a value greater than zero. (5) The principle of fault determination when the control section 13a of the auxiliary input unit 10 turns off the relay switches 12a and 12c and turns on the relay switches 12b and 12d will be described. (5-1) When the relay switches 12a, 12b, 12c, and 12d are normal, the following occurs.

[0174] That is, when relay switch 12a is turned off, it opens the gap between output terminal 11c of AC-DC converter 11 and relay switch 12b. When relay switch 12b is turned on, it connects relay switch 12a and input terminal 22a of DC / DC converter 22.

[0175] When relay switch 12c is turned off, it disconnects output terminal 11c of AC-DC converter 11 from relay switch 12d. When relay switch 12d is turned on, it connects relay switch 12c and input terminal 22b of DC / DC converter 22.

[0176] In this case, the instantaneous value of the input voltage Vin becomes a full-wave rectified waveform, and the instantaneous value of the output voltage Vout becomes zero volts. As a result, the effective value of the output voltage of the relay unit 12 becomes zero. (5-2) When the relay switches 12b and 12d are normal and the relay switches 12a and 12c are turned on due to a welding failure, the following occurs.

[0177] That is, when relay switch 12a is turned on, it connects output terminal 11c of AC-DC converter 11 to relay switch 12b. When relay switch 12b is turned on, it connects relay switch 12a to input terminal 22a of DC / DC converter 22.

[0178] When relay switch 12c is turned on, it connects output terminal 11c of AC-DC converter 11 to relay switch 12d. When relay switch 12d is turned on, it connects relay switch 12c to input terminal 22b of DC / DC converter 22.

[0179] In this case, the instantaneous value of the input voltage, Vin, has a full-wave rectified waveform. The instantaneous value of the output voltage, Vout, also has a full-wave rectified waveform. Therefore, the effective value of the output voltage is a positive value greater than zero.

[0180] As described above, the control unit 13a determines whether the relay switches 12a and 12c are faulty by determining whether the output voltage is equal to or greater than the threshold value in step S230 of Fig. 13. The threshold value is a value greater than zero.

[0181] (6) The principle of fault determination when the control unit of the auxiliary input unit turns on each of the relay switches 12a, 12b, 12c, and 12d will be described. (6-1) When the relay switches 12a, 12b, 12c, and 12d are normal, the following occurs.

[0182] In this case, the instantaneous value of the input voltage Vin has a full-wave rectified waveform, and the instantaneous value of the output voltage Vout also has a full-wave rectified waveform. As a result, the effective value of the output voltage of the relay unit 12 becomes a positive value greater than zero. (6-2) As shown in FIG. 22, when at least one of the relay switches 12a, 12b, 12c, and 12d fails and turns off, the following occurs. 22 shows a state in which relay switch 12a, out of relay switches 12a, 12b, 12c, and 12d, has failed and is turned off. The dashed line in FIG. 22 shows a case in which relay switch 12a is normal.

[0183] In this case, the instantaneous value of the input voltage Vout becomes a full-wave rectified waveform, and the instantaneous value of the output voltage Vout becomes zero volts.

[0184] In this case, the control unit 13a executes the processes of steps S310 to S340 in FIG. 14 as follows.

[0185] That is, the control unit 13a obtains a subtraction value ΔV by subtracting the effective value of the output voltage of the relay unit 12 (ie, the output side voltage) from the effective value of the input voltage of the relay unit 12 (ie, the input side voltage).

[0186] The control unit 13a determines whether or not the calculated subtraction value ΔV is equal to or greater than a threshold value, thereby determining whether or not any one of the relay switches 12a, 12b, 12c, and 12d is faulty.

[0187] When the subtraction value ΔV is equal to or greater than the threshold value, the control unit 13a determines that one of the relay switches 12a, 12b, 12c, and 12d is faulty and makes a YES determination in step S310. Accordingly, the control unit 13a executes the all relays OFF control process in step S330 and the abnormality notification process in step S340, similar to the first embodiment. On the other hand, when the subtraction value ΔV is less than the threshold value, the control unit 13a determines that the relay switches 12a, 12b, 12c, and 12d are normal, and makes a NO determination in step S310. Accordingly, the control unit 13a executes the power supply start process in step S320, similarly to the first embodiment.

[0188] The control unit 13a may execute the determination process of step S310 in FIG. 14 as follows. That is, in step S310 of FIG. 14, the control unit 13a determines whether or not the effective value of the output voltage of the relay unit 12 is equal to or less than the threshold value.

[0189] When the effective value of the output voltage of the relay unit 12 is equal to or less than the threshold value, the control unit 13a determines that one of the relay switches 12a, 12b, 12c, and 12d is faulty, and determines YES in step S310.

[0190] On the other hand, when the effective value of the output voltage of the relay unit 12 is greater than the threshold value, the control unit 13a determines that all of the relay switches 12a, 12b, 12c, and 12d are normal, and makes a NO determination in step S310.

[0191] According to the present embodiment described above, the power supply system 1 includes the AC-DC converter 11 that converts the output voltage of the auxiliary power supply 3 into an AC voltage and outputs it from output terminals 11c and 11d. The power supply system 1 also includes the inverter circuit 21 that converts the output voltage of the AC-DC converter, which is provided to input terminals 21a and 21b via the DC / DC converter 22, into an AC voltage.

[0192] The power supply system 1 is arranged between an output terminal 11c of the AC-DC converter 11 and an input terminal 22a of the DC / DC converter 22, and includes relay switches 12a and 12b connected in series.

[0193] The power supply system 1 is arranged between the output terminal 11d of the AC-DC converter 11 and the input terminal 22b of the DC / DC converter 22, and includes relay switches 12c and 12d connected in series.

[0194] The power supply system 1 outputs the output voltage of only one of the auxiliary power supply 3 and the system power supply 2 to the electric load 6 in the house.

[0195] When control unit 13a receives the power supply permission notification from control unit 26a and determines that relay switches 12a, 12b, 12c, and 12d are normal, control unit 26a controls inverter circuit 21. Therefore, inverter circuit 21 converts the output voltage provided from AC-DC converter 11 through DC / DC converter 22 into an AC voltage and outputs it to electrical loads 6 in the house.

[0196] When the control unit 13a receives the power supply permission notification from the control unit 26a and determines that at least one of the relay switches 12a, 12b, 12c, and 12d is faulty, the control unit 13a turns off all of the relay switches 12a, 12b, 12c, and 12d. As a result, the control unit 13a prohibits the auxiliary power supply 3 from supplying power to the electric loads 6 in the house.

[0197] As described above, it is possible to provide the power supply system 1 that prohibits the auxiliary power supply 3 from supplying power to the electric loads 6 in the house when the relay switches 12a, 12b, 12c, and 12d fail.

[0198] The power supply system 1 of this embodiment configured as above can achieve the following effects.

[0199] In other words, even if the relay unit 12 fails and prohibits the supply of power from the auxiliary power supply 3 to the electrical loads 6 in the home, the control unit 26a is configured to be able to control the inverter circuit 21, as in the first embodiment described above.

[0200] Therefore, even if the relay unit 12 breaks down, the output voltage of the solar cell 4 or the storage battery 5 can be converted into an AC voltage by the inverter circuit 21 and output to the electrical load 6 in the house.

[0201] This makes it possible to continue supplying the output power of the solar cell 4 and the storage battery 5 to the electrical loads 6 in the home without shutting down the entire power conditioner 20 when the relay switches 12a, 12b, 12c, and 12d fail.

[0202] (Other embodiments) (1) In the above first and second embodiments, an example was described in which the control unit 13a executes the input side relay welding determination process, the output side relay welding determination process, and the relay OFF fault determination process in this order when executing the relay control process.

[0203] However, the control unit 13a may execute the input-side relay welding determination process and the output-side relay welding determination process after the relay-OFF failure determination process, or may execute the output-side relay welding determination process before the input-side relay welding determination process. (2) In the first and second embodiments, the electric load is the residential electric load 6. However, instead of this, the electric load may be a factory electric load or a building electric load. (3) In the first and second embodiments, an example was described in which the inverter circuit 21 outputting an AC voltage with an effective value of single-phase 100 V was used as the DC-AC converter. However, instead of this, the inverter circuit 21 outputting an AC voltage with an effective value of single-phase 200 V may be used as the DC-AC converter.

[0204] Alternatively, an inverter circuit 21 that outputs an AC voltage with an effective value of single-phase 100V and an AC voltage with an effective value of single-phase 200V may be used as the DC-AC converter. (4) In the first and second embodiments, the communication processing unit 13b and the communication processing unit 26b communicate with each other via a communication line. However, instead of this, the communication processing unit 13b and the communication processing unit 26b may communicate with each other wirelessly. (5) The present invention is not limited to the above-described embodiments and can be modified as appropriate within the scope of the claims. Furthermore, the above-described embodiments are not unrelated to each other and can be combined as appropriate unless the combination is clearly impossible. It goes without saying that, in each of the above-described embodiments, elements constituting the embodiments are not necessarily essential unless they are specifically stated as essential or are clearly considered essential in principle. Furthermore, in each of the above-described embodiments, when numerical values ​​such as the number, values, amounts, and ranges of components of the embodiments are mentioned, they are not limited to the specific numbers unless they are specifically stated as essential or are clearly limited to a specific number in principle. [Explanation of symbols]

[0205] 1 Power supply system 2 power supplies 3 Auxiliary power supply 11 AC-DC converter 21 Inverter circuit 12 Relay Unit 12a relay switch 12b Relay Switch 12c relay switch 12d Relay Switch 13a Control section 26a Control section

Claims

1. an AC / DC converter (11) having a first input terminal (11a) and a second input terminal (11b) to which an AC voltage output from an auxiliary power supply (3) is input, and which converts the input AC voltage into a DC voltage and outputs the DC voltage; a DC / AC converter (21) that converts the output voltage of the AC / DC converter into an AC voltage; When two terminals of the auxiliary power supply from which the AC voltage is output are a first output terminal (3a) and a second output terminal (3b), a first input side switch (12a) and a second input side switch (12b) are arranged between the first output terminal and the first input terminal and are connected in series; a third input-side switch (12c) and a fourth input-side switch (12d) that are connected in series and are disposed between the second output terminal and the second input terminal; a first control unit (13a); a second control unit (26a), outputting an output voltage of either the auxiliary power supply or the system power supply (2) to an electrical load (6); when the first control unit receives from the second control unit a power supply permission notification indicating that power supply from the auxiliary power supply to the electrical load is permitted and determines that the first input side switch, the second input side switch, the third input side switch, and the fourth input side switch are all normal, the second control unit controls the DC-AC converter to convert an output voltage of the AC-DC converter into the AC voltage and output the AC voltage to the electrical load, When the first control unit receives the power supply permission notification from the second control unit and determines that at least one of the first input side switch, the second input side switch, the third input side switch, and the fourth input side switch has failed, the first control unit turns off the first input side switch, the second input side switch, the third input side switch, and the fourth input side switch, respectively, to prohibit power supply from the auxiliary power supply to the electrical load.

2. an AC / DC converter (11) having a first output terminal (11c) and a second output terminal (11d), which converts an AC voltage output from an auxiliary power supply (3) into a DC voltage and outputs the DC voltage from the first output terminal and the second output terminal; a DC / AC converter (21) having a first input terminal (21a) and a second input terminal (21b), and converting an output voltage of the AC / DC converter applied to the first input terminal and the second input terminal into an AC voltage; a first input-side switch (12a) and a second input-side switch (12b) that are connected in series and are disposed between the first output terminal and the first input terminal; a third input-side switch (12c) and a fourth input-side switch (12d) that are connected in series and are disposed between the second output terminal and the second input terminal; a first control unit (13a); a second control unit (26a), outputting an output voltage of either the auxiliary power supply or the system power supply (2) to an electrical load (6); when the first control unit receives from the second control unit a power supply permission notification indicating that power supply from the auxiliary power supply to the electrical load is permitted and determines that the first input side switch, the second input side switch, the third input side switch, and the fourth input side switch are all normal, the second control unit controls the DC-AC converter to convert an output voltage of the AC-DC converter into the AC voltage and output the AC voltage to the electrical load, When the first control unit receives the power supply permission notification from the second control unit and determines that at least one of the first input side switch, the second input side switch, the third input side switch, and the fourth input side switch has failed, the first control unit turns off the first input side switch, the second input side switch, the third input side switch, and the fourth input side switch, respectively, to prohibit power supply from the auxiliary power supply to the electrical load.

3. When the auxiliary power source is a first auxiliary power source (3), an auxiliary power converter (23, 24) is provided for converting the output voltage of the second auxiliary power source (4, 5) into a predetermined DC voltage; The power supply system according to claim 1 or 2, wherein the second control unit controls the DC-AC converter to convert an output voltage of the second auxiliary power supply into the AC voltage and output the AC voltage to the electrical load.

4. an output-side switch (25a, 25b) disposed between the electrical load and the system power supply; 3. The power supply system according to claim 1, wherein the second control unit controls the DC-AC converter to convert the output voltage of the AC-DC converter into the AC voltage and output the AC voltage to the electrical load while the output-side switch is turned off.

Images