Solar charging system

Abstract

To provide a solar charging system in which the charging efficiency of power generated by a solar panel can be enhanced.SOLUTION: A solar charging system installed in a vehicle, includes: a power generation module that uses a solar panel; an auxiliary battery that stores power generated by the power generation module; an auxiliary load that receives power supply from the auxiliary battery; a driving battery that is used to drive the vehicle; and a control unit that is provided between the driving battery and the auxiliary battery, and controls power transfer between these batteries. In a case where there is no current flowing to the auxiliary battery, the control unit supplies, to the driving battery, power other than power consumed by the auxiliary load out of the power generated by the power generation module.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a solar charging system that controls the supply of electric power generated by a solar panel mounted on a vehicle.

Background Art

[0002] Patent Document 1 discloses a solar charging system that, when a solar panel is in a power generation-enabled state, supplies power from the solar panel to an auxiliary equipment system to derive the actual power generated by the solar panel, and if the derived actual power generation power is equal to or greater than a specified value, further charges a driving battery with the power generation power of the solar panel.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a system that directly charges an auxiliary battery without storing the power generated by a solar panel in a dedicated energy storage element, even if the solar panel generates power equal to or greater than a specified value, the charging efficiency of the solar-generated power may decrease depending on the state of the auxiliary battery to be charged. Therefore, there is room for further consideration regarding the charging method of the solar-generated power implemented in the solar charging system.

[0005] The present disclosure has been made in view of the above problems, and an object thereof is to provide a solar charging system capable of improving the charging efficiency of the power generated by a solar panel.

Means for Solving the Problems

[0006] In order to solve the above problems, one aspect of the disclosed technology is a solar charging system mounted on a vehicle, comprising a power generation module using a solar panel, an auxiliary battery for storing the generated power of the power generation module, an auxiliary load supplied with power from the auxiliary battery, a driving battery used for driving the vehicle, and a control unit provided between the driving battery and the auxiliary battery for controlling the power transfer between the two batteries. When there is no current flowing into the auxiliary battery, the control unit supplies the power other than the power consumed by the auxiliary load among the generated power of the power generation module to the driving battery.

Advantages of the Invention

[0007] According to the solar charging system of the present disclosure, the charging efficiency of the power generated by the solar panel can be improved.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Embodiments for Carrying Out the Invention

[0009] The solar charging system according to the present disclosure determines the power supply destination (charging destination) of the power generated by the solar power generation module based on the current flowing in and out of the auxiliary battery. Thereby, the charging efficiency can be improved according to the state of the auxiliary battery regardless of the magnitude of the solar generated power. Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0010] <Embodiment> [Configuration] FIG. 1 is a block diagram showing a schematic configuration of a solar charging system 1 according to an embodiment of the present disclosure and its periphery. The solar charging system 1 illustrated in FIG. 1 includes a solar power generation module 10, a driving battery 20, an auxiliary battery 30, and a bidirectional DC / DC converter 40. Further, the solar charging system 1 is connected to an auxiliary load 100 so as to be able to supply power.

[0011] As an example, this solar charging system 1 can be mounted on vehicles such as a hybrid vehicle (HEV), a plug-in hybrid vehicle (PHEV), and an electric vehicle (BEV).

[0012] The solar power generation module 10 is a power generation device that generates power by receiving sunlight, and outputs the generated power to an auxiliary battery 30, an auxiliary load 100, etc. connected to the solar power generation module 10. This solar power generation module 10 includes a solar panel that is an aggregate of solar cells, a solar DC / DC converter that outputs the power generated by the solar panel at a predetermined voltage, a solar control unit that executes maximum power point tracking (MPPT) control, etc. (not shown). The generated power of the solar panel is calculated from measurement values of sensors and measuring instruments (not shown).

[0013] The drive battery 20 is a secondary battery configured to be chargeable and dischargeable, such as a lithium-ion battery or a nickel-metal hydride battery. This drive battery 20 is connected to a main device (not shown) for driving the vehicle and can supply the electric power necessary for the operation of this main device. Examples of the main device include a starter motor and a traction motor. The drive battery 20 is connected to the solar power generation module 10 via a bidirectional DCDC converter 40 so as to be chargeable with the electric power generated by the solar panel of the solar power generation module 10. Further, the drive battery 20 is connected to the accessory battery 30 via a bidirectional DCDC converter 40 so as to be chargeable with the electric power stored in the accessory battery 30. This drive battery 20 is a high-voltage battery having a rated voltage higher than that of the accessory battery 30.

[0014] The accessory battery 30 is a secondary battery configured to be chargeable and dischargeable, such as a lithium-ion battery or a lead-acid battery. This accessory battery 30 can supply the electric power necessary for the operation of the accessory load 100 to the accessory load 100. The accessory battery 30 is connected to the solar power generation module 10 so as to be chargeable with the electric power generated by the solar panel of the solar power generation module 10. Further, the accessory battery 30 is connected to the drive battery 20 via a bidirectional DCDC converter 40 so as to be chargeable with the electric power stored in the drive battery 20. The charge amount (storage amount) of this accessory battery 30, the current flowing in and out of the accessory battery 30, etc. are monitored by sensors and measuring instruments (not shown).

[0015] The bidirectional DC-DC converter 40 is a bidirectional power converter that can convert the input power into power of a predetermined voltage and output it. One end of this bidirectional DC-DC converter 40 (referred to as the primary side) is connected to the solar power generation module 10, the auxiliary battery 30, and the auxiliary load 100, and the other end (referred to as the secondary side) is connected to the drive battery 20. The bidirectional DC-DC converter 40 can supply (pumping charge) the power output from the solar power generation module 10 and the auxiliary battery 30 connected to the primary side to the drive battery 20 connected to the secondary side. Also, the bidirectional DC-DC converter 40 can supply (drawing charge) the power of the drive battery 20 connected to the secondary side to the auxiliary battery 30 and the auxiliary load 100 connected to the primary side. During this power supply, the bidirectional DC-DC converter 40 boosts the voltage of the auxiliary battery 30 input to the primary side to obtain the output voltage on the secondary side (during the boost operation), and also steps down the voltage of the drive battery 20 input to the secondary side to obtain the output voltage on the primary side (during the buck operation). Note that instead of the bidirectional DC-DC converter 40, two unidirectional DC-DC converters may be provided with the power transfer directions reversed from each other.

[0016] The above-described bidirectional DC-DC converter 40, together with an electronic control unit (not shown) that controls the conversion operation, etc., constitutes a control unit that controls the power transfer between the drive battery 20 and the auxiliary battery 30. This control unit can acquire the power generated by the solar panel of the solar power generation module 10 (solar power generation power), the stored power of the auxiliary battery 30, and the current flowing in and out of the auxiliary battery 30. The control executed by the control unit will be described later. Note that this control unit may be provided as a configuration independent of the bidirectional DC-DC converter 40.

[0017] The auxiliary load 100 is various auxiliary devices mounted on the vehicle. The auxiliary load 100 operates by receiving the power generated by the solar power generation module 10 or the power stored in the auxiliary battery 30. Examples of such auxiliary devices 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 driver assistance.

[0018] [Control] Next, with further reference to FIGS. 2, 3, and 4, the control performed in the solar charging system 1 according to the present embodiment will be described. FIG. 2 is a flowchart for explaining the processing procedure of the charging control executed by the solar charging system 1. FIG. 3 is a diagram for explaining the power supply (charging) state from the solar power generation module 10 to the auxiliary load 100 and the driving battery 20. FIG. 4 is a diagram for explaining the power supply (charging) state from the solar power generation module 10 to the auxiliary battery 30 and the auxiliary load 100.

[0019] The charging control illustrated in FIG. 2 is started, for example, when the solar panel of the solar power generation module 10 generates electricity, and is repeatedly executed until the solar panel stops generating electricity.

[0020] (Step S201) The solar charging system 1 determines whether or not there is no current flowing into the auxiliary battery 30 (whether it is zero). This determination is made to grasp whether the auxiliary battery 30 is in a state where it can be charged. The source (supply source) of the current flowing into the auxiliary battery 30 is typically the solar power generation module 10. If there is no current flowing into the auxiliary battery 30 when the current source is the solar power generation module 10, it can be determined that there is a surplus in the power generated by the solar panel. Note that the current source also includes other power supply systems (for example, backup power supply systems) other than the driving battery 20 connected to the auxiliary battery 30.

[0021] When the solar charging system 1 determines that there is no (zero) current flowing into the auxiliary battery 30 (step S201, yes), the process proceeds to step S202. On the other hand, when the solar charging system 1 determines that there is current flowing into the auxiliary battery 30 (step S201, no), the process proceeds to step S204.

[0022] (Step S202) The solar charging system 1 determines whether there is no current flowing out of the auxiliary battery 30 (whether it is zero). This determination is made to ascertain whether power transfer (pumping charge) from the auxiliary battery 30 to the driving battery 20 is being carried out. If the pumping charge is being carried out, it can be determined that the bidirectional DCDC converter 40 is already operating in a high-efficiency boost mode. In such a case, if the power generated by the solar panel is boosted and additionally supplied to the driving battery 20, the boost efficiency of the bidirectional DCDC converter 40 may conversely decrease.

[0023] When the solar charging system 1 determines that there is no current flowing out of the auxiliary battery 30 (zero) (step S202, yes), the process proceeds to step S203. On the other hand, when the solar charging system 1 determines that there is current flowing out of the auxiliary battery 30 (step S202, no), the process proceeds to step S204.

[0024] (Step S203) The solar charging system 1 supplies the power generated by the solar panel of the solar power generation module 10 to the auxiliary load 100. Further, the solar charging system 1 outputs (charges) the surplus power (the power remaining after consumption by the auxiliary load 100) among the generated power of this solar panel to the driving battery 20 via the bidirectional DCDC converter 40. The power supply states from the solar power generation module 10 to the auxiliary load 100 and the driving battery 20 are as shown in FIG. 3.

[0025] When the power generated by the solar panel is supplied to the auxiliary load 100 based on the state of the auxiliary battery 30 by the solar charging system 1 and the surplus power is charged to the driving battery 20, this charging control ends.

[0026] (Step S204) The solar charging system 1 supplies (charges) the power generated by the solar panel of the solar power generation module 10 to the auxiliary battery 30 and also supplies it to the auxiliary load 100. The power supply states from the solar power generation module 10 to the auxiliary battery 30 and the auxiliary load 100 are as shown in FIG. 4.

[0027] When the power generated by the solar panel is supplied to the auxiliary battery 30 and also supplied to the auxiliary load 100 based on the state of the auxiliary battery 30 by the solar charging system 1, this charging control ends.

[0028] <Function and Effect> As described above, according to the solar charging system 1 according to an embodiment of the present disclosure, while there is a current flowing into the auxiliary battery 30, the auxiliary battery 30 is charged with the power generated by the solar power generation module 10, and the power generated by the solar power generation module 10 is also supplied to the auxiliary load 100. And according to the solar charging system 1 according to this embodiment, when the current flowing into the auxiliary battery 30 disappears, while continuously supplying the power generated by the solar power generation module 10 to the auxiliary load 100, the driving battery 20 is charged with the surplus power not consumed by the auxiliary load 100.

[0029] By this control, it is possible to determine that there is a margin in the power generation amount of the solar panel without using a control threshold value or the like, so that the charging efficiency of the power generated by the solar panel can be improved. Also, by this control, the number of times of voltage conversion in the bidirectional DCDC converter 40 can be minimized, so that the power loss associated with voltage conversion can be reduced.

[0030] In the above embodiment, an example of determining whether or not there is a current flowing into the auxiliary battery 30 in the solar charging system 1 has been described. However, the same control can be performed by determining the charge amount (fully charged state) of the auxiliary battery 30.

[0031] As described above, one embodiment of the disclosed technology has been described. However, the present disclosure can be regarded not only as a solar charging system but also as a charging control method, a program for the method, a computer-readable non-transitory storage medium storing the program, a vehicle equipped with the solar charging system, and the like.

Industrial Applicability

[0032] The solar charging system of the present disclosure can be used in vehicles equipped with solar panels and the like.

Explanation of Signs

[0033] 1 Solar charging system 10 Solar power generation module 20 Driving battery 30 Auxiliary battery 40 Bidirectional DCDC converter 100 Auxiliary load

Claims

1. A solar charging system mounted on a vehicle, comprising: a power generation module using a solar panel; an auxiliary battery for storing the generated power of the power generation module; an auxiliary load supplied with power from the auxiliary battery; a driving battery used for driving the vehicle; a control unit provided between the driving battery and the auxiliary battery for controlling power transfer between the two batteries; When there is no current flowing into the auxiliary battery and no current flowing out of the auxiliary battery, the control unit supplies the generated power of the power generation module to the auxiliary load, and supplies the power other than the power consumed by the auxiliary load in the generated power of the power generation module to the driving battery. A solar charging system.

2. When there is a current flowing into the auxiliary battery, or when there is no current flowing into the auxiliary battery and there is a current flowing out of the auxiliary battery, the control unit supplies the generated power of the power generation module to the auxiliary battery and the auxiliary load, and does not supply it to the driving battery. The solar charging system according to claim 1.

3. The solar charging system according to claim 1 or 2, wherein the control unit includes a DC-DC converter that boosts the power input from the power generation module and outputs it to the driving battery.

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