Power device

Abstract

To make more effective use of the electricity generated by a solar panel.SOLUTION: A power conditioner 100 includes a voltage detection unit 101 that detects the output voltage of a solar cell panel 200, a current detection unit 102 that detects the output current of the solar cell panel 200, an inverter circuit 105 that can convert the power generated by the solar cell panel 200 into AC power and supply it to a load 300, and a control unit 106 that stops the switching operation of an inverter circuit 105 for at least a part of a period during which the power generated by the solar cell panel 200 is equal to or less than a predetermined inverter stop power on the basis of the detection values of the voltage detection unit 101 and the current detection unit 102, and the power conditioner 100 is connected to a second DC / DC converter circuit 402a that can operate in a charging mode in which the power generated by the solar cell panel 200 is supplied to a vehicle battery 401a.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power device that converts power generated by a solar panel into AC power and supplies it to a load. [Background technology]

[0002] The power device disclosed in Patent Document 1 converts power generated by a solar cell panel into AC power and supplies it to a load. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 8-265982 Summary of the Invention [Problem to be solved by the invention]

[0004] In a power device that not only supplies the power generated by a solar panel to a load but also charges a storage battery, if the inverter circuit that converts the generated power into AC power is operated when the generated power is low, the proportion of power consumed by the inverter circuit relative to the power supplied to the load and the power charging the storage battery becomes high, resulting in a lot of wasted power.

[0005] The present invention has been made in view of the above points, and an object of the present invention is to more effectively utilize the power generated by a solar cell panel. [Means for solving the problem]

[0006] In order to achieve the above object, a first aspect of the present disclosure is a power device that converts power generated by a solar cell panel into AC power and supplies it to a load, comprising: a voltage detection unit that detects the output voltage of the solar cell panel; a current detection unit that detects the output current of the solar cell panel; an inverter circuit having a plurality of switching elements and capable of converting the power generated by the solar cell panel into AC power and supplying it to the load by switching operations of the plurality of switching elements; and a control unit that stops the switching operation of the inverter circuit by referring to the detection values ​​of the voltage detection unit and the detection values ​​of the current detection unit, during at least a part of a period during which the power generated by the solar cell panel is equal to or less than a predetermined inverter stop power, and is connected to a converter circuit that can operate in a charging mode to supply the power generated by the solar cell panel to a storage battery main body.

[0007] This stops the switching operation of the inverter circuit during at least part of the period when the power generated by the solar panel is below the inverter stop power, thereby reducing the power consumption of the inverter circuit and making more effective use of the power generated by the solar panel compared to when the inverter circuit is constantly operating.

[0008] A second aspect of the present disclosure is characterized in that, in the first aspect, the converter circuit is further capable of operating in a discharge mode to discharge power stored in the storage battery main body, and the inverter circuit is further capable of converting the power discharged by the converter circuit in the discharge mode into AC power and supplying it to the load.

[0009] A third aspect of the present disclosure is characterized in that, in the second aspect, the converter circuit is provided in a V2H system connected to a stationary storage battery or a vehicle battery.

[0010] A fourth aspect of the present disclosure is characterized in that, in the first to third aspects, the control unit causes the inverter circuit to perform the switching operation when the power generated by the solar cell panel exceeds a predetermined inverter return power that is greater than the inverter stop power, stops the switching operation of the inverter circuit when the power generated by the solar cell panel is equal to or less than the inverter stop power, and does not switch the switching operation of the inverter circuit between a stopped state and an operating state when the power generated by the solar cell panel is equal to or less than the inverter return power and exceeds the inverter stop power.

[0011] This makes it possible to prevent the inverter circuit from frequently repeating the stopping and starting of its switching operation.

[0012] A fifth aspect of the present disclosure is characterized in that, in the first to third aspects, the control unit causes the inverter circuit to stop the switching operation when the state in which the power generated by the solar panel is less than the inverter stop power continues for a predetermined waiting time while the inverter circuit is performing the switching operation, and causes the inverter circuit to start the switching operation when the state in which the power generated by the solar panel is greater than the inverter stop power continues for a predetermined waiting time while the inverter circuit is performing the switching operation.

[0013] This makes it possible to prevent the inverter circuit from frequently repeating the stopping and starting of its switching operation.

[0014] A sixth aspect of the present disclosure is characterized in that, in the first to third aspects, the control unit causes the inverter circuit to perform the switching operation when the current mode is a time period in which charging is not performed, or a mode in which charging is performed using power other than that generated by the solar panel. [Effects of the Invention]

[0015] According to the present disclosure, the power generated by the solar panel can be used more effectively. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a block diagram showing the configuration of a power supply system according to a first embodiment of the present disclosure. [Figure 2] FIG. 2 is a circuit diagram of the inverter circuit. [Figure 3] FIG. 3 is a flowchart illustrating the operation of the control unit. [Figure 4] FIG. 4 is a timing chart illustrating the power generated by the solar cell panel, the operating state of the inverter circuit, and the state of the storage battery when the switching operation of the inverter circuit is stopped. [Figure 5] FIG. 5 is a diagram equivalent to FIG. 4 when the inverter circuit starts a switching operation. [Figure 6] FIG. 6 is a timing chart showing two types of transitions in the power generated by a solar panel: in one transition, the period during which the slope of the charging power is approximately equal to the slope of the generated power, and in the other transition, the period during which the slope of the charging power is approximately equal to the slope of the generated power. [Figure 7] FIG. 7 is a graph illustrating the amount of power generated by solar power generation by weather. [Figure 8] FIG. 8 is a view corresponding to FIG. 4 of the second embodiment. [Figure 9] FIG. 9 is a view equivalent to FIG. 5 of the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.

[0018] First Embodiment 1 shows the configuration of a power supply system 1. The power supply system 1 includes a power conditioner 100 as a power device according to the first embodiment of the present disclosure, a solar panel 200, a load 300, a vehicle 401 equipped with a vehicle battery 401a as a storage battery main body, a V2H (Vehicle to Home) 402 connected to the vehicle battery 401a, and a stationary storage battery 403.

[0019] An input terminal of the power conditioner 100 is connected to the solar cell panel 200, and an output terminal of the power conditioner 100 is connected to a load 300 and a system power supply 500. Therefore, the power conditioner 100 can convert the power generated by the solar cell panel 200 into AC power and supply it to the load 300 and the power system.

[0020] The power conditioner 100 is also connected to the V2H 402 and the stationary storage battery 403. The power conditioner 100 can supply power generated by the solar cell panel 200 to the vehicle battery 401a of the vehicle 401 and the stationary storage battery 403. Furthermore, the power conditioner 100 can supply power stored in the vehicle battery 401a of the vehicle 401 and the stationary storage battery 403 to the load 300 and the power grid.

[0021] The power conditioner 100 includes a voltage detection unit 101, a current detection unit 102, a first DC / DC converter circuit 103, an inverter circuit 105, and a control unit .

[0022] The voltage detection unit 101 detects the output voltage of the solar cell panel 200 .

[0023] The current detection unit 102 detects the output current of the solar cell panel 200 .

[0024] The first DC / DC converter circuit 103 converts the output voltage of the solar cell panel 200 into a predetermined DC voltage and outputs it to the first DC bus 107 .

[0025] An input terminal of the inverter circuit 105 is connected to the first DC bus 107. An output terminal of the inverter circuit 105 is connected to the load 300 and the system power supply 500.

[0026] As shown in FIG. 2, the inverter circuit 105 has first and second input terminals 105a, 105b, a first capacitor 105c, a first upper arm switching element 105d, a first lower arm switching element 105e, a second upper arm switching element 105f, a second lower arm switching element 105g, first and second reactors 105h, 105i, a second capacitor 105j, and first and second output terminals 105k, 105m.

[0027] The first and second input terminals 105a and 105b are connected to a first DC bus 107. The first and second output terminals 105k and 105m are connected to a load 300 and a system power supply 500.

[0028] The first capacitor 105c is connected between the first and second input terminals 105a and 105b.

[0029] The first upper arm switching element 105d and the first lower arm switching element 105e are connected in series between the first and second input terminals 105a and 105b.

[0030] The second upper arm switching element 105f and the second lower arm switching element 105g are connected in series between the first and second input terminals 105a and 105b.

[0031] The first output terminal 105k is connected to a connection point between the first upper arm switching element 105d and the first lower arm switching element 105e via a first reactor 105h.

[0032] The second output terminal 105m is connected to a connection point between the second upper arm switching element 105f and the second lower arm switching element 105g via a second reactor 105i.

[0033] The second capacitor 105j is connected between the first and second output terminals 105k and 105m.

[0034] With the above-described configuration, the inverter circuit 105 can convert DC power output to the first DC bus 107 into AC power through the switching operations of the multiple switching elements 105d to 105g and supply the AC power to the load 300 and the power system. More specifically, the inverter circuit 105 can convert the power generated by the solar cell panel 200 and output by the first DC / DC converter circuit 103 into AC power and supply the AC power to the load 300 and the power system. Furthermore, the inverter circuit 105 can convert power discharged from the V2H 402 and the stationary storage battery 403 into AC power and supply the AC power to the load 300 and the power system.

[0035] The control unit 106 refers to the detection values ​​of the voltage detection unit 101 and the current detection unit 102, and stops the switching operation of the inverter circuit 105 while the power generated by the solar cell panel 200 is equal to or less than a predetermined inverter stop power.

[0036] More specifically, after power is turned on, the control unit 106 repeatedly executes the operation shown in FIG. 3 at predetermined time intervals (for example, every 0.1 seconds).

[0037] In the operation shown in FIG. 3, the control unit 106 first determines in S101 whether the current mode is a mode in which only power generated by the solar cell panel 200 is used for charging. If the control unit 106 determines that the current mode is a mode in which only power generated by the solar cell panel 200 is used for charging, the control unit 106 proceeds to processing in S102. On the other hand, if the control unit 106 determines that the current mode is not a mode in which only power generated by the solar cell panel 200 is used for charging, the control unit 106 proceeds to processing in S106. In addition to a mode in which only power generated by the solar cell panel 200 is used for charging, there are other modes, such as a time period in which charging is not performed, and a mode in which power other than that generated by the solar cell panel 200 is charged. The time period in which charging is performed may be set by a user through an input device (not shown), or may be set using artificial intelligence (AI).

[0038] In S102, the control unit 106 determines whether the power generated by the solar cell panel 200 exceeds a predetermined inverter return power. This inverter return power is greater than the inverter stop power. The power generated by the solar cell panel 200 can be calculated by referring to the detection value of the voltage detection unit 101 and the detection value of the current detection unit 102. If the control unit 106 determines that the power generated by the solar cell panel 200 exceeds this inverter return power, the control unit 106 proceeds to processing of S104. On the other hand, if the control unit 106 determines that the power generated by the solar cell panel 200 does not exceed the predetermined inverter return power, the control unit 106 proceeds to processing of S103.

[0039] In S103, the control unit 106 determines whether the power generated by the solar cell panel 200 exceeds a predetermined inverter stop power. This inverter stop power is set to be smaller than the inverter return power. If the control unit 106 determines that the power generated by the solar cell panel 200 exceeds the inverter stop power, the control unit 106 does not switch the switching operation of the inverter circuit 105 between a stopped state and an operating state, and ends the flow. On the other hand, if the control unit 106 determines that the power generated by the solar cell panel 200 is equal to or less than the predetermined inverter stop power, the control unit 106 proceeds to the processing of S105.

[0040] In S104, the control unit 106 causes the switching elements 105d to 105g of the inverter circuit 105 to perform switching operations. As a result, the power generated by the solar cell panel 200 is sent to the V2H 402, the stationary storage battery 403, the load 300, and the system power supply 500.

[0041] In S105, the control unit 106 stops the switching operations of the switching elements 105d to 105g of the inverter circuit 105. As a result, the power generated by the solar cell panel 200 is sent to the V2H 402 and the stationary storage battery 403, but is not sent to the load 300 and the system power supply 500.

[0042] In S106, the control unit 106 causes the switching elements 105d to 105g of the inverter circuit 105 to perform switching operations. As a result, the power generated by the solar cell panel 200 is sent to the V2H 402, the stationary storage battery 403, the load 300, and the system power supply 500.

[0043] The V2H 402 is provided with a second DC / DC converter circuit 402a. The second DC / DC converter circuit 402a is a bidirectional converter that can operate in a charge mode and a discharge mode. The first DC bus 107 of the power conditioner 100 is connected to the second DC / DC converter circuit 402a. Therefore, in the charge mode, the second DC / DC converter circuit 402a converts the voltage of the first DC bus 107, i.e., the output voltage of the first DC / DC converter circuit 103, into a predetermined DC voltage and outputs it to the vehicle battery 401a. That is, in the charge mode, the second DC / DC converter circuit 402a supplies the power generated by the solar panel 200 to the vehicle battery 401a. On the other hand, in the discharge mode, the second DC / DC converter circuit 402a converts the output voltage of the vehicle battery 401a into a predetermined voltage and outputs it to the first DC bus 107. That is, in the discharge mode, the second DC / DC converter circuit 402a can discharge the power stored in the vehicle battery 401a to the inverter circuit 105. The inverter circuit 105 can convert the power discharged from the second DC / DC converter circuit 402a into AC power and supply it to the load 300 and the power grid.

[0044] The stationary storage battery 403 is provided with a third DC / DC converter circuit 403a and a storage battery main body 403b. The third DC / DC converter circuit 403a is a bidirectional converter that can operate in a charge mode and a discharge mode. The third DC / DC converter circuit 403a is connected to the first DC bus 107 of the power conditioner 100. Therefore, in the charge mode, the third DC / DC converter circuit 403a converts the voltage of the first DC bus 107, i.e., the output voltage of the first DC / DC converter circuit 103, into a predetermined DC voltage and outputs it to the storage battery main body 403b. That is, in the charge mode, the third DC / DC converter circuit 403a supplies the power generated by the solar cell panel 200 to the storage battery main body 403b. On the other hand, in the discharge mode, the third DC / DC converter circuit 403a converts the output voltage of the storage battery main body 403b into a predetermined voltage and outputs it to the first DC bus 107. That is, in the discharge mode, the third DC / DC converter circuit 403a can discharge the power stored in the storage battery main body 403b to the inverter circuit 105. The inverter circuit 105 can convert the power discharged from the third DC / DC converter circuit 403a into AC power and supply it to the load 300 and the power grid.

[0045] In the power supply system 1 configured as described above, as shown in Fig. 4, while the vehicle battery 401a and the stationary storage battery 403 are being charged and the inverter circuit 105 is performing a switching operation, at time t1, even if the power generated by the solar cell panel 200 becomes equal to or less than the inverter recovery power, as long as it is greater than the inverter shutdown power, the control unit 106 causes the inverter circuit 105 to continue the switching operation. At time t2, when the power generated by the solar cell panel 200 becomes equal to or less than the inverter shutdown power, the control unit 106 causes the inverter circuit 105 to stop the switching operation. This reduces the power consumption of the inverter circuit 105, and makes it possible to increase the charging power to the vehicle battery 401a and the stationary storage battery 403 accordingly.

[0046] 5, while charging the vehicle battery 401a and the stationary storage battery 403 and stopping the switching operation of the inverter circuit 105, even if the power generated by the solar cell panel 200 exceeds the inverter stop power at time t3, the control unit 106 does not cause the inverter circuit 105 to start the switching operation because the power is equal to or less than the inverter recovery power. After that, at time t4, when the power generated by the solar cell panel 200 exceeds the inverter recovery power, the control unit 106 causes the inverter circuit 105 to start the switching operation.

[0047] In FIG. 6, graph G1 shows the transition of the power generated by solar cell panel 200 when the power generated by solar cell panel 200 decreases relatively suddenly. Graph G2 shows the transition of the power generated by solar cell panel 200 when the power generated by solar cell panel 200 decreases relatively slowly. In graph G1, the power generated by solar cell panel 200 falls below the inverter stop power at time t5, and inverter circuit 105 stops switching operation. Then, in period TG1 from time t5, the charging power decreases at a slope approximately equal to the power generated by solar cell panel 200. Also, in graph G2, the power generated by solar cell panel 200 falls below the inverter stop power at time t6, and inverter circuit 105 stops switching operation. Then, in period TG2 from time t6, the charging power decreases at a slope approximately equal to the power generated by solar cell panel 200.

[0048] 7, the power generated by the solar cell panel 200 varies greatly depending on the weather and the time of day. According to the first embodiment, the switching operation of the inverter circuit 105 is stopped during a period when the power generated by the solar cell panel 200 is equal to or less than the inverter stop power, so that the power consumption of the inverter circuit 105 can be reduced and the power generated by the solar cell panel 200 can be used more effectively than when the inverter circuit 105 is constantly operating.

[0049] If the current mode is a time period in which charging is not performed or a mode in which power other than the power generated by the solar cell panel 200 is charged, the control unit 106 causes the inverter circuit 105 to perform a switching operation.

[0050] Furthermore, as shown in FIG. 3, when the power generated by the solar panel 200 is equal to or less than the inverter recovery power and exceeds the inverter shutdown power, the switching operation of the inverter circuit 105 is not switched between a stopped state and an operating state, thereby preventing the inverter circuit 105 from frequently repeating the stopping and starting of its switching operation.

[0051] Second Embodiment FIG. 8 is a diagram equivalent to FIG. 4 of the second embodiment, and FIG. 9 is a diagram equivalent to FIG. 5 of the second embodiment. In the power supply system 1 according to the second embodiment, the inverter return power and the inverter stop power are set equal to each other. As shown in FIG. 8, the control unit 106 causes the inverter circuit 105 to stop its switching operation when the power generated by the solar cell panel 200 remains equal to or less than the inverter stop power for a predetermined waiting time TW1 while the inverter circuit 105 is performing its switching operation. As shown in FIG. 9, the control unit 106 causes the inverter circuit 105 to start its switching operation when the power generated by the solar cell panel 200 remains greater than the inverter return power (inverter stop power) for a predetermined waiting time TW2 while the inverter circuit 105 is performing its switching operation.

[0052] In this way, the control unit 106 refers to the detection value of the current detection unit 102 and the detection value of the voltage detection unit 101, and stops the switching operation of the inverter circuit 105 during a part of the period when the power generated by the solar panel 200 is equal to or less than the inverter stop power.

[0053] The other configurations and operations are the same as those in the first embodiment, so detailed explanations thereof will be omitted.

[0054] As described above, in the second embodiment, when the inverter circuit 105 is performing a switching operation, even if the power generated by the solar cell panel 200 becomes equal to or less than the inverter stop power, the inverter circuit 105 is not caused to stop its switching operation unless the state in which the power generated is equal to or less than the inverter stop power continues for a predetermined waiting time TW1. Also, when the switching operation of the inverter circuit 105 is stopped, even if the power generated by the solar cell panel 200 exceeds the inverter recovery power, the inverter circuit 105 is not caused to start its switching operation unless the state in which the power generated is greater than the inverter recovery power continues for a predetermined waiting time TW2. Therefore, it is possible to prevent the inverter circuit 105 from frequently repeatedly stopping and starting its switching operation.

[0055] In the above first and second embodiments, the storage batteries to which the second and third DC / DC converter circuits 402a, 403a supply the generated power of the solar cell panel 200 are the vehicle battery 401a and the storage battery main body 403b of the stationary storage battery 403, but it may be either one of them. [Industrial Applicability]

[0056] The present disclosure is useful as a power device that converts power generated by a solar cell panel into AC power and supplies the AC power to a load. [Explanation of symbols]

[0057] 100 Power conditioner (power device) 101 Voltage detection unit 102 Current detection unit 105 Inverter circuit 105d~105g Switching elements 106 Control Unit 200 solar panels 300 load 401a Vehicle battery (storage battery body) 402a Second DC / DC Converter Circuit 403a Third DC / DC Converter Circuit 403b Storage battery body

Claims

1. A power device that converts power generated by a solar panel into AC power and supplies it to a load, a voltage detection unit that detects an output voltage of the solar cell panel; a current detection unit that detects an output current of the solar panel; an inverter circuit having a plurality of switching elements, the inverter circuit being capable of converting power generated by the solar cell panel into AC power by switching operations of the plurality of switching elements and supplying the AC power to the load; a control unit that refers to a detection value of the voltage detection unit and a detection value of the current detection unit and stops the switching operation of the inverter circuit during at least a part of a period when the power generated by the solar cell panel is equal to or less than a predetermined inverter stop power, a power device connected to a converter circuit operable in a charging mode for supplying power generated by the solar cell panel to a storage battery body;

2. 2. The power device according to claim 1, the converter circuit is further operable in a discharge mode in which it discharges the power stored in the storage battery body; The power device is characterized in that the inverter circuit is further capable of converting the power discharged by the converter circuit in the discharge mode into AC power and supplying the AC power to the load.

3. 3. The power device according to claim 2, The power device is characterized in that the converter circuit is provided in a V2H connected to a stationary storage battery or a vehicle battery.

4. The power device according to any one of claims 1 to 3, the control unit causes the inverter circuit to perform the switching operation when the power generated by the solar cell panel exceeds a predetermined inverter return power that is greater than the inverter stop power; When the power generated by the solar panel is equal to or less than the inverter stop power, the switching operation of the inverter circuit is stopped; and When the power generated by the solar panel is equal to or less than the inverter recovery power and exceeds the inverter shutdown power, the power device does not switch the switching operation of the inverter circuit between a stopped state and an operating state.

5. The power device according to any one of claims 1 to 3, the control unit causes the inverter circuit to stop the switching operation when a state in which the power generated by the solar panel is equal to or less than the inverter stop power continues for a predetermined waiting time while the inverter circuit is performing the switching operation, and causes the inverter circuit to start the switching operation when a state in which the power generated by the solar panel is greater than the inverter stop power continues for a predetermined waiting time while the inverter circuit is stopping the switching operation.

6. The power device according to any one of claims 1 to 3, The power device is characterized in that the control unit causes the inverter circuit to perform the switching operation when the current mode is a mode in which charging is not performed or a mode in which charging is performed using power other than that generated by the solar panel.

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