Solar charging system

Abstract

To provide a solar charging system capable of efficiently controlling the charging using the power generated by solar panels when the charge amount acceptable by an auxiliary battery is limited.SOLUTION: A solar charging system includes: a plurality of solar panels; an auxiliary battery charged by the power generated by solar panels; a main battery different from the auxiliary battery; and a control unit that is placed between the auxiliary battery and the main battery for controlling the charging of the main battery with the generated power. In the solar charging system, the control unit is configured to, when the charge amount acceptable by an auxiliary battery is limited and when the charge capacity of the main battery is greater than that of the auxiliary battery, control the generated power to be capable of charging the generated power to the main battery.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a solar charging system that controls charging of a battery using power generated by a solar panel. [Background technology]

[0002] Patent Document 1 discloses a solar charging system in which, when the solar panel is in a state where it can generate power, the solar panel supplies power to an auxiliary system including an auxiliary battery, and the power actually generated by the solar panel is derived; if this derived actual generated power is equal to or greater than a specified value, the power generated by the solar panel is further used to charge the main battery. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-083248 Summary of the Invention [Problem to be solved by the invention]

[0004] Because the charge amount that an auxiliary battery can accept varies depending on its condition (such as its charge rate and temperature), the charge amount may be limited to protect the battery. However, the solar charging system disclosed in the above-mentioned Patent Document 1 does not perform control to switch the charging destination of the power generated by the solar panel depending on the charge amount that the auxiliary battery can accept. Therefore, if the charge amount that the auxiliary battery can accept is limited, there is a risk that the power generated by the solar panel will not be used efficiently.

[0005] Therefore, there is room for further consideration regarding the charging method for the auxiliary battery implemented in the solar charging system, including cases where the amount of charge that the auxiliary battery can accept is limited.

[0006] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a solar charging system that can efficiently control charging using power generated by a solar panel when the amount of charge that the auxiliary battery can accept is limited. [Means for solving the problem]

[0007] In order to solve the above problems, one aspect of the disclosed technology is a solar charging system comprising a solar panel, an auxiliary battery (first battery) that is charged by the power generated by the solar panel, a main battery (second battery) that is different from the auxiliary battery, and a control unit that is provided between the auxiliary battery and the main battery and controls the charging of the main battery by the generated power, wherein when the amount of charge that the auxiliary battery can accept is limited, the control unit controls the generated power to a state where it can charge the main battery if the chargeable amount of the main battery is greater than the chargeable amount of the auxiliary battery. [Effects of the Invention]

[0008] According to the solar charging system of the present disclosure, when the amount of charge that the auxiliary battery can accept is limited, the battery with the largest possible charge capacity is determined to be the battery to be charged, thereby enabling efficient control of charging using power generated by the solar panel. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a block diagram of a solar charging system and its peripheral components according to an embodiment of the present disclosure. [Figure 2] A flowchart of the battery charging control process executed by the solar charging system. [Figure 3] Detailed processing flowchart of step S203 in FIG. 2 [Figure 4] Detailed processing flowchart of step S204 in FIG. 2 [Figure 5] Image explaining battery charging mode selection example DETAILED DESCRIPTION OF THE INVENTION

[0010] When the amount of charge that the auxiliary battery can accept is limited, the solar charging system of the present disclosure determines whether it is more efficient to charge the auxiliary battery with the power generated by the solar panel or to charge the main battery, based on the chargeable amounts of the auxiliary battery and the main battery. Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0011] <Embodiment> [composition] Fig. 1 is a block diagram showing a schematic configuration of a solar charging system 110 and its peripheral parts according to an embodiment of the present disclosure. The solar charging system 110 shown in Fig. 1 includes a solar power generation module 111, a main battery 112, an auxiliary battery 113, and a control unit 114. The solar charging system 110 is also connected to a main load 120 and an auxiliary load 130 so as to be able to supply power.

[0012] This solar charging system 110 can be mounted on vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs), for example. The following describes the case where the solar charging system 110 is mounted on a vehicle.

[0013] The solar power generation module 111 is a power generation device that generates power when exposed to sunlight, and outputs the generated power to an auxiliary battery 113 connected to the solar power generation module 111, an auxiliary load 130 connected to the auxiliary battery 113, etc. This solar power generation module 111 is configured to include a solar panel which is an assembly of solar battery cells, an MPPT control unit (MPPT) that realizes the maximum power point of power generation in the solar panel by tracking control, etc. The power generated by the solar panel is calculated from measurements of various sensors (not shown), etc.

[0014] The main battery 112 (second battery) is a secondary battery, such as a lithium-ion battery, that is configured to be chargeable and dischargeable. The main battery 112 is connected to a main load 120 included in the main system, and can supply the power necessary for the operation of the main load 120. The main battery 112 is connected to the solar power generation module 111 via a control unit 114 so that it can be charged using power generated by a solar panel. The main battery 112 is also connected to the auxiliary battery 113 via the control unit 114 so that it can supply its own stored power to the auxiliary battery 113 and can be charged using power stored in the auxiliary battery 113. The main battery 112 is, for example, a drive battery with a higher rated voltage than the auxiliary battery 113.

[0015] The auxiliary battery 113 (first battery) is a secondary battery that can be charged and discharged, such as a lithium-ion battery or a lead-acid battery. The auxiliary battery 113 is connected to an auxiliary load 130 included in the auxiliary system and can supply the power necessary for the operation of the auxiliary load 130. The auxiliary battery 113 can also supply power for driving a system required for charging and controlling the power generated by the solar panel. The auxiliary battery 113 is connected to the solar power generation module 111 so as to be rechargeable with the power generated by the solar panel. The auxiliary battery 113 is also connected to the main battery 112 via the control unit 114 so as to be rechargeable with the power stored in the main battery 112 and to be able to supply the power stored in the main battery 112 itself. The charge rate, temperature, etc. of the auxiliary battery 113 are monitored by various sensors (not shown).

[0016] The control unit 114 is a bidirectional power converter that can convert input power into power of a predetermined voltage and output the power, and is typically configured as an electronic control unit including a bidirectional DC-DC converter (bidirectional DDC). One end (primary side) of this control unit 114 is connected to the solar power generation module 111 and the auxiliary battery 1130, and the other end (secondary side) is connected to the main battery 1120. The control unit 114 can supply (pumping charge) power output from the solar power generation module 111 and the auxiliary battery 1130 connected to one end to the main battery 1120 connected to the other end. During this power supply, the control unit 114 performs a boost operation to boost the voltage of the auxiliary battery 113 input to one end to generate an output voltage at the other end. The control unit 114 can also supply (pumping charge) power from the main battery 112 connected to the other end to the auxiliary battery 113 connected to one end. When supplying this power, the control unit 114 performs a step-down operation to step down the voltage of the main battery 112 input to the other end to make it the output voltage of the one end.

[0017] The control unit 114 can also acquire the power generated by the solar panel in the solar power generation module 111, the state (power storage rate, temperature, etc.) of the main battery 112, and the state (power storage rate, temperature, etc.) of the auxiliary battery 113. Furthermore, the control unit 114 can determine whether or not the amount of charge that the main battery 112 can accept is limited, and whether or not the amount of charge that the auxiliary battery 113 can accept is limited. The control performed by this control unit 114 will be described later.

[0018] The main engine load 120 is various main engine-like devices mounted on the vehicle. The main engine load 120 is powered by the main engine battery 112 and operates by receiving a supply of electric power stored in the main engine battery 112. An example of this main engine load 120 is an electric motor for driving the vehicle.

[0019] The auxiliary load 130 is various auxiliary devices mounted on the vehicle. The auxiliary load 130 is powered by the solar power generation module 111 and the auxiliary battery 113, and operates by receiving power generated by the solar panel and power stored in the auxiliary battery 113. Examples of the auxiliary load 130 include lighting devices such as headlamps and interior lights, air conditioning devices such as heaters and air conditioners, and systems for autonomous driving and advanced driving assistance.

[0020] [control] Next, the control performed in the solar charging system 110 according to this embodiment will be described with further reference to Figures 2, 3, and 4. Figure 2 is a flowchart (main routine) illustrating the processing procedure for battery charging control executed by the control unit 114 of the solar charging system 110. Figure 3 is a flowchart (subroutine) illustrating the detailed processing procedure for setting the auxiliary equipment chargeable amount in step S203 of Figure 2. Figure 4 is a flowchart (subroutine) illustrating the detailed processing procedure for setting the main equipment chargeable amount in step S204 of Figure 2.

[0021] The battery charging control illustrated in Figures 2, 3, and 4 is started, for example, when the solar panel of the solar power generation module 111 generates power exceeding a predetermined power, and is repeated until the power generated by the solar panel falls below the predetermined power.

[0022] A: Main routine (Figure 2) (Step S201) The control unit 114 determines whether the charge amount that the auxiliary battery 113 can accept is limited. The charge amount is limited, for example, when the state of charge (SOC) of the auxiliary battery 113 is equal to or higher than a predetermined charge amount, or when the temperature of the auxiliary battery 113 is equal to or higher than a predetermined temperature. The control unit 114 can determine that the auxiliary battery 113 is limited based on status information of specific components, etc. The limited charge amount is appropriately determined depending on the full charge capacity of the auxiliary battery 113, the performance and specifications of the vehicle, etc. If the charge amount of the auxiliary battery 113 is limited (step S201, YES), the process proceeds to step S202. On the other hand, if the charge amount of the auxiliary battery 113 is not limited (step S201, NO), the process proceeds to step S206.

[0023] (Step S202) The control unit 114 acquires information about the power currently being generated by the solar panel as a result of receiving solar radiation from the solar power generation module 111. Once the power generated by the solar panel has been acquired, the process proceeds to step S203.

[0024] (Step S203) The control unit 114 sets the charge amount that the auxiliary battery 113 can be charged with (hereinafter referred to as "auxiliary chargeable amount"). A method for setting this auxiliary chargeable amount will be described later with reference to Fig. 3. Once the auxiliary chargeable amount is set, the process proceeds to step S204.

[0025] (Step S204) The control unit 114 sets the charge amount that can be charged to the main battery 112 (hereinafter referred to as the "main battery chargeable amount"). A method for setting this main battery chargeable amount will be described later with reference to Figure 4. Once the main battery chargeable amount has been set, the process proceeds to step S205.

[0026] (Step S205) The control unit 114 compares the chargeable capacity of the auxiliary equipment with the chargeable capacity of the main equipment and determines whether the chargeable capacity of the auxiliary equipment is equal to or greater than the chargeable capacity of the main equipment. If the chargeable capacity of the auxiliary equipment is equal to or greater than the chargeable capacity of the main equipment (step S205, Yes), the process proceeds to step S206. On the other hand, if the chargeable capacity of the auxiliary equipment is less than the chargeable capacity of the main equipment (step S205, No), the process proceeds to step S207.

[0027] (Step S206) The control unit 114 selects (switches) the "auxiliary battery charging mode" for charging the auxiliary battery 113 (auxiliary system) with power generated by the solar panel to perform solar charging in charge control of the solar charging system 110. When the charging mode to be controlled is selected, the process proceeds to step S201.

[0028] (Step S207) The control unit 114 selects (switches to) a "main battery charging mode" for charging the main battery 112 (main system) with power generated by the solar panel for charging control of the solar charging system 110, and performs solar charging. When the charging mode to be controlled is selected, the process proceeds to step S201.

[0029] Note that if the auxiliary chargeable capacity and the main chargeable capacity are the same, the solar charging efficiency will not change whether the auxiliary battery charging mode or the main battery charging mode is implemented. Therefore, in step S205, it may be determined whether the auxiliary chargeable capacity is greater than the main chargeable capacity. In other words, if the determination in step S205 is equal (=), the main battery charging mode (step S207) may be selected.

[0030] B: Subroutine (Figure 3) (Step S301) The control unit 114 derives a first power consumption related to the auxiliary battery 113. This first power consumption is the power consumed by the auxiliary battery 113 based on the operation of a system required to charge the auxiliary battery 113 with power generated by the solar panel. In this case, the required system includes components such as an MPPT control unit of the solar power generation module 111 and a monitoring ECU (not shown) of the auxiliary battery 113, and these components operate using the auxiliary battery 113 as a power source. Note that the first power consumption may also include the power consumed by the auxiliary load 130 when solar charging is performed. Once the first power consumption of the auxiliary battery 113 is derived, the process proceeds to step S302.

[0031] (Step S302) The control unit 114 compares the power generated by the solar panel with the first power consumption of the auxiliary battery 113, and determines whether the power generated is greater than the first power consumption. If the power generated is greater than the first power consumption (Yes in step S302), the process proceeds to step S303. On the other hand, if the power generated is equal to or less than the first power consumption (No in step S302), the process proceeds to step S307.

[0032] (Step S303) The control unit 114 derives a first available charge amount for the auxiliary battery 113. This first available charge amount is the amount of charge obtained by power generation by the solar panel that can be substantially used to charge the auxiliary battery 113, and can be derived based on the power generated by the solar panel minus the first power consumption of the auxiliary battery 113. Once the first available charge amount for the auxiliary battery 113 is derived, the process proceeds to step S304.

[0033] (Step S304) The control unit 114 compares the first available charge amount for the auxiliary battery 113 with the limited charge amount of the auxiliary battery 113, which limits the amount of charge that the auxiliary battery 113 can accept (hereinafter referred to as the "limited auxiliary charge amount"), and determines whether the first available charge amount is greater than the limited auxiliary charge amount. This limited auxiliary charge amount is as described above. If the first available charge amount is greater than the limited auxiliary charge amount (Yes in step S304), the process proceeds to step S305. On the other hand, if the first available charge amount is equal to or less than the limited auxiliary charge amount (No in step S302), the process proceeds to step S306.

[0034] (Step S305) The control unit 114 sets the auxiliary limited charge amount to the auxiliary chargeable amount because the charge amount that can currently be stored in the auxiliary battery 113 by solar charging exceeds the auxiliary limited charge amount of the auxiliary battery 113. When the auxiliary chargeable amount is set to the auxiliary limited charge amount, this subroutine ends and the process returns to step S204.

[0035] (Step S306) The control unit 114 sets the first available charge amount to the auxiliary chargeable amount because the charge amount that can currently be stored in the auxiliary battery 113 by solar charging is equal to or less than the auxiliary charge limit amount of the auxiliary battery 113. When the first available charge amount is set to the auxiliary chargeable amount, this subroutine ends and the process returns to step S204.

[0036] (Step S307) Since solar charging may reduce (take away) the amount of electricity stored in the auxiliary battery 113, the control unit 114 sets the auxiliary chargeable amount to zero. When the auxiliary chargeable amount is set to zero, this subroutine ends and the process returns to step S204.

[0037] C: Subroutine (Figure 4) (Step S401) The control unit 114 derives a second power consumption related to the auxiliary battery 113. This second power consumption is the power consumed by the auxiliary battery 113 based on the operation of a system required for charging the main battery 112 with power generated by the solar panel. In this case, the required system includes components such as an MPPT control unit of the solar power generation module 111 and a monitoring ECU (not shown) for the auxiliary battery 113, as well as the control unit 114 and a monitoring ECU (not shown) for the main battery 112, and these components operate using the auxiliary battery 113 as a power source. Note that the second power consumption may also include the power consumed by the main load 120 and the auxiliary load 130 when solar charging is performed. Once the second power consumption of the auxiliary battery 113 has been derived, the process proceeds to step S402.

[0038] (Step S402) The control unit 114 compares the power generated by the solar panel with the second power consumption of the auxiliary battery 113, and determines whether the power generated is greater than the second power consumption. If the power generated is greater than the second power consumption (Yes in step S402), the process proceeds to step S403. On the other hand, if the power generated is equal to or less than the second power consumption (No in step S402), the process proceeds to step S407.

[0039] (Step S403) The control unit 114 derives a second available charge amount for the main battery 112. This second available charge amount is the amount of charge obtained by power generation by the solar panel that can be substantially used to charge the main battery 112, and can be derived based on the power generated by the solar panel minus the second power consumption of the auxiliary battery 113. Once the second available charge amount for the main battery 112 is derived, the process proceeds to step S404.

[0040] (Step S404) The control unit 114 compares the second effective charge amount for the main battery 112 with a limited charge amount for the main battery 112 that limits the amount of charge that can be accepted (hereinafter referred to as the "main battery limited charge amount"), and determines whether the second effective charge amount is greater than the main battery limited charge amount. The charge amount is limited, for example, when the state of charge (SOC) of the main battery 112 is equal to or greater than a predetermined state of charge, or when the temperature of the main battery 112 is equal to or greater than a predetermined temperature. The main battery limited charge amount is appropriately determined depending on the full charge capacity of the main battery 112, the performance and specifications of the vehicle, and the like. If the second effective charge amount is greater than the main battery limited charge amount (Yes in step S404), the process proceeds to step S405. On the other hand, if the second effective charge amount is equal to or less than the main battery limited charge amount (No in step S402), the process proceeds to step S406.

[0041] (Step S405) The control unit 114 sets the main engine limited charge amount to the main engine chargeable amount because the charge amount that can currently be stored in the main engine battery 112 through solar charging exceeds the main engine limited charge amount of the main engine battery 112. When the main engine limited charge amount is set to the main engine chargeable amount, this subroutine ends and the process returns to step S204.

[0042] (Step S406) The control unit 114 sets the second available charge amount to the main engine chargeable amount because the charge amount that can currently be stored in the main engine battery 112 through solar charging is equal to or less than the main engine limited charge amount of the main engine battery 112. When the second available charge amount is set as the main engine chargeable amount, this subroutine ends and the process returns to step S204.

[0043] (Step S307) The control unit 114 sets the main engine chargeable capacity to zero because there is a risk that solar charging will reduce (take away) the amount of electricity stored in the auxiliary battery 113. When the main engine chargeable capacity is set to zero, this subroutine ends and the process returns to step S204.

[0044] [Specific example] Figure 5 is an illustration of an example of selection between the auxiliary battery charging mode and the main battery charging mode. In Figure 5, the vertical axis represents the power generated by the solar panel, and the magnitude of the generated power is indicated by a shaded rectangle. In Figure 5, the thin solid double-headed arrow indicates the first available charge amount, the thick solid double-headed arrow indicates the second available charge amount, the thin dashed double-headed arrow indicates the accessory limited charge amount, the thick dashed double-headed arrow indicates the main limited charge amount, and the hollow single-headed arrow indicates the state in which the charge amount of the main battery 112 and the auxiliary battery 113 is limited.

[0045] 5(a), the generated power does not reach the second power consumption for the main battery 112, and only the auxiliary battery 113 generates the first effective charge amount. Therefore, in this case, the auxiliary battery charging mode is selected.

[0046] 5(b), the auxiliary battery 113 generates a first effective charge amount, and the main battery 112 generates a second effective charge amount. There is no charge amount limit for either the main battery 112 or the auxiliary battery 113, and the first effective charge amount (= the auxiliary battery chargeable amount) is greater than the second effective charge amount (= the main battery chargeable amount). Therefore, in this case, the auxiliary battery charging mode is selected.

[0047] In the case of the power generation shown in Figure 5(c), the auxiliary battery 113 generates a first effective charge amount, and the main battery 112 generates a second effective charge amount. Here, the auxiliary battery 113 has a charge amount limit, but the limited auxiliary charge amount (= auxiliary chargeable amount) is greater than the second effective charge amount (= main chargeable amount). Therefore, in this case, the auxiliary battery charging mode is selected. In this case, part of the power generated by the solar panel (the limited amount indicated by the white single arrow) is discarded.

[0048] 5(d), the auxiliary battery 113 generates the first effective charge amount, and the main battery 112 generates the second effective charge amount. Here, because the charge amount of the auxiliary battery 113 is limited, the limited auxiliary charge amount (= the auxiliary chargeable amount) becomes smaller than the second effective charge amount (= the main chargeable amount). Therefore, in this case, the main battery charging mode is selected.

[0049] In the case of the power generation shown in Figure 5(e), the auxiliary battery 113 generates a first effective charge amount, and the main battery 112 generates a second effective charge amount. Here, the main battery 112 and the auxiliary battery 113 each have a charge amount limit, and the auxiliary limited charge amount (= auxiliary chargeable amount) is greater than the main battery limited charge amount (= main battery chargeable amount). Therefore, in this case, the auxiliary battery charging mode is selected. In this case, part of the power generated by the solar panel (the limited amount indicated by the white arrow on the auxiliary side) is discarded.

[0050] <Actions and Effects> As described above, when the charge amount that the auxiliary battery 113 (first battery) can accept is limited (smaller than normal), the solar charging system 110 according to an embodiment of the present disclosure determines which case will result in a greater solar charge to the battery: discarding part of the power generated by the solar panel to charge the auxiliary battery 113, or charging the main battery 112 (second battery) without discarding the power generated by the solar panel. This allows for efficient control of charging using the power generated by the solar panel.

[0051] Furthermore, in the solar charging system 110 according to this embodiment, when the charge capacity of the auxiliary battery 113 is limited, the charging mode is switched between the auxiliary battery charging mode and the main battery charging mode based on the chargeable capacity of each battery. This makes it possible to suppress a decrease in the charge capacity and the generation of carry-over power when switching between charging modes, thereby ensuring the charge capacity of the battery.

[0052] The above describes one embodiment of the disclosed technology, but the present disclosure can be understood as not only a solar charging system, but also a battery charging control method, a program for that method, a computer-readable non-transitory storage medium storing the program, a vehicle equipped with a solar charging system, and the like. [Industrial Applicability]

[0053] The solar charging system of the present disclosure can be used in vehicles equipped with solar panels. [Explanation of symbols]

[0054] 110 Solar Charging System 111 Solar power generation module 112 Main engine battery 113 Auxiliary Battery 114 Control section (bidirectional DDC) 120 Main engine load 130 Auxiliary Load

Claims

1. Solar panels and a first battery that is charged by the power generated by the solar panel; a second battery different from the first battery; a control unit provided between the first battery and the second battery and configured to control charging of the second battery with the generated power, When the charge amount that the first battery can accept is limited, and the chargeable amount of the second battery is greater than the chargeable amount of the first battery, the control unit controls the generated power to be charged into the second battery. Solar charging system.

2. The case where the acceptable charge amount of the first battery is limited includes at least one of a case where the charge rate of the first battery is equal to or higher than a predetermined charge rate and a case where the temperature of the first battery is equal to or higher than a predetermined temperature. The solar charging system according to claim 1 .

3. the chargeable amount of the first battery and the chargeable amount of the second battery are set based on the generated power, a limited charge amount of the first battery in which the acceptable charge amount is limited, a first power consumption of the first battery based on operation of a system required to charge the first battery with the generated power, and a second power consumption of the first battery based on operation of a system required to charge the second battery with the generated power, respectively. The solar charging system according to claim 1 or 2.

4. The chargeable amount of the first battery is as follows: When the generated power is equal to or less than the first consumed power, zero is set; When the generated power is greater than the first consumed power and a first available charge amount derived based on the generated power and the first consumed power is greater than the limited charge amount, the limited charge amount is set; When the generated power is greater than the first consumed power and the first available charge amount is equal to or less than the limited charge amount, the first available charge amount is set; The chargeable amount of the second battery is as follows: When the generated power is equal to or less than the second consumed power, zero is set; When the generated power is greater than the second consumed power and a second available charge amount derived based on the generated power and the second consumed power is greater than the limited charge amount, the limited charge amount is set; When the generated power is greater than the second consumed power and the second available charge amount is equal to or less than the limited charge amount, the second available charge amount is set. The solar charging system according to claim 3 .

5. It is mounted on a vehicle, the first battery is an auxiliary battery that supplies power to an auxiliary system mounted on the vehicle, The second battery is a main engine battery that supplies power to a main engine system mounted on the vehicle. The solar charging system according to any one of claims 1 to 4.

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