Solar Charging System

Abstract

To provide a solar charging system in which the charging efficiency of power of an auxiliary battery and solar generation power can be improved during pumping charging.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, a driving battery that is used to drive the vehicle, and a control unit that is disposed between the driving battery and the auxiliary battery and controls power transfer between the batteries. In a case where the generated power outputted by the power generation module is equal to or larger than a first threshold and the amount of power stored in the auxiliary battery is equal to or larger than a second threshold, the control unit supplies power from both the power generation module and the auxiliary battery to the driving battery.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 technology]

[0002] Patent Document 1 discloses a solar charging system in which, when the solar panel is in a state where it can generate electricity, the solar panel first supplies power to an auxiliary system, deriving the power actually generated by the solar panel, and if this derived actual generated power is equal to or greater than a specified value that allows efficient charging to the auxiliary system, the drive battery is charged with the power generated by the solar panel. [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] Generally, when transferring power from an auxiliary battery to a drive battery (sometimes called pumping charging), the DC-DC converter that converts voltage between the batteries outputs power from the auxiliary battery at a high efficiency. Therefore, in a system that directly charges the auxiliary battery with power generated by a solar panel without storing it in a dedicated storage element, even if the solar panel can generate a large amount of power that can be provided to the drive battery during pumping charging, solar power generation must be performed at an operating point with low power generation efficiency, resulting in a decrease in the charging efficiency of the solar-generated power.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a solar charging system that can improve the charging efficiency of auxiliary battery power and solar-generated power during pumping charging. [Means for solving the problem]

[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 that stores the power generated by the power generation module; a drive battery used to drive the vehicle; and a control unit provided between the drive battery and the auxiliary battery that controls the transfer of power between the two batteries, wherein the control unit supplies power to the drive battery from both the power generation module and the auxiliary battery when the generated power output by the power generation module is equal to or greater than a first threshold and the amount of power stored in the auxiliary battery is equal to or greater than a second threshold. [Effects of the Invention]

[0007] According to the solar charging system of the present disclosure, the charging efficiency of the auxiliary battery's power and the solar-generated power can be improved during pumping charging. [Brief explanation of the drawings]

[0008] [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] Processing flowchart of charging control executed by the solar charging system [Figure 3] An example of the boost efficiency of a bidirectional DC-DC converter [Figure 4] Diagram explaining an example of the power transfer path (solar power generation module + auxiliary battery → drive battery) [Figure 5] Diagram explaining an example of the power transfer path (solar power generation module → auxiliary battery) DETAILED DESCRIPTION OF THE INVENTION

[0009] The solar charging system according to the present disclosure determines the power output from the auxiliary battery by prioritizing the power generated by the solar power generation module so that the drive battery can be charged with power that is highly efficient for the DC-DC converter when pumping charging from the auxiliary battery to the drive battery. This improves the charging efficiency of the auxiliary battery power and the solar-generated power during pumping charging. Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0010] <Embodiment> [composition] Fig. 1 is a block diagram showing a schematic configuration of a solar charging system 1 and its peripheral parts according to an embodiment of the present disclosure. The solar charging system 1 shown in Fig. 1 includes a solar power generation module 10, a drive battery 20, an auxiliary battery 30, and a bidirectional DC-DC converter 40. This solar charging system 1 is mounted on vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs).

[0011] The solar power generation module 10 is a power generation device that generates electricity when exposed to sunlight and outputs the generated power to an auxiliary battery 30 and an auxiliary load 100 that are connected to the solar power generation module 10. The solar power generation module 10 includes a solar panel which is an assembly of solar battery cells, a solar DC-DC converter that outputs the power generated by the solar panel at a predetermined voltage, and a solar control unit that performs maximum power point tracking (MPPT) control (not shown). The power generated by the solar panel is calculated from measurements by sensors and measuring instruments (not shown).

[0012] The drive battery 20 is a rechargeable secondary battery, such as a lithium-ion battery or a nickel-metal hydride battery. The drive battery 20 is connected to a main device (not shown) for driving the vehicle and can supply the power necessary to operate the main device. Examples of main devices include a starter motor and an electric motor for driving. The drive battery 20 is also connected to the solar power generation module 10 via a bidirectional DC-DC converter 40 so that it can be charged using power generated by a solar panel. The drive battery 20 is a high-voltage battery with a higher rated voltage than the auxiliary battery 30.

[0013] The auxiliary battery 30 is a secondary battery configured to be chargeable and dischargeable, such as a lithium-ion battery or a lead-acid battery. The auxiliary battery 30 can supply the auxiliary load 100 with the power required for the operation of the auxiliary load 100. The auxiliary battery 30 is connected to the solar power generation module 10 so that it can be charged with power generated by a solar panel. The auxiliary battery 30 is also connected to the bidirectional DC-DC converter 40 so that it can be charged with power stored in the drive battery 20. The charge amount (amount of stored power) of the auxiliary battery 30 is monitored by sensors, measuring instruments, etc. (not shown).

[0014] The bidirectional DC-DC converter 40 is a bidirectional power converter that can convert input power into power of a predetermined voltage and output it. One end (called the primary side) of this bidirectional DC-DC converter 40 is connected to the solar power generation module 10, the auxiliary battery 30, and the auxiliary load 100, and the other end (called the secondary side) is connected to the drive battery 20. The bidirectional DC-DC converter 40 can supply (pumping charge) 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. The bidirectional DC-DC converter 40 can also supply power from 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 produce an output voltage on the secondary side (in boost operation), and also lowers the voltage of the drive battery 20 input to the secondary side to produce an output voltage on the primary side (in step-down operation). Instead of the bidirectional DC-DC converter 40, two unidirectional DC-DC converters may be provided with the power transfer directions reversed.

[0015] The above-mentioned bidirectional DC-DC converter 40, together with an electronic control unit (not shown) that controls the operation of the converter, 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 (solar-generated power) generated by the solar panel of the solar power generation module 10, the amount of power stored in the auxiliary battery 30, etc. The control performed by the control unit will be described later.

[0016] The auxiliary load 100 is a variety of auxiliary equipment mounted on a vehicle. The auxiliary load 100 operates by receiving power generated by the solar power generation module 10 or power stored in the auxiliary battery 30. Examples of such auxiliary equipment include lighting equipment such as headlamps and interior lights, air conditioning equipment such as heaters and air conditioners, and systems for autonomous driving and advanced driving assistance.

[0017] [control] Next, the control performed in the solar charging system 1 according to this embodiment will be described with further reference to Fig. 2 and Fig. 3. Fig. 2 is a flowchart illustrating the procedure of the charging control executed by the solar charging system 1. Fig. 3 is a diagram showing an example of the boost efficiency of the bidirectional DC-DC converter 40.

[0018] The charging control illustrated in FIG. 2 is started when a request is made to transfer power from the auxiliary battery 30 to the drive battery 20 (pumping charge) in the vehicle.

[0019] (Step S201) The solar charging system 1 determines whether the power generated by the solar panel of the solar power generation module 10 is equal to or greater than a first threshold. This determination is made to determine whether the power generated by the solar panel can be charged efficiently. Therefore, the first threshold can be set to a predetermined power level that prevents the power consumption of the ECU and other components required for charging the drive battery 20 or the auxiliary battery 30 from the power generated by the solar panel, and thus prevents a decrease in energy efficiency.

[0020] If the solar charging system 1 determines that the power generated by the solar panel is equal to or greater than the first threshold (step S201, Yes), the process proceeds to step S202. On the other hand, if the solar charging system 1 determines that the power generated by the solar panel is less than the first threshold (step S201, No), the process proceeds to step S205.

[0021] (Step S202) The solar charging system 1 determines whether the amount of stored power (charge amount) of the auxiliary battery 30 is equal to or greater than a second threshold. This determination is made to determine whether the auxiliary battery 30 has stored therein a sufficient amount of power that can be used for pumping charging. Therefore, the second threshold is set to a predetermined power that allows efficient use of charging power based on the performance and capacity of the auxiliary battery 30.

[0022] If the solar charging system 1 determines that the amount of stored power in the auxiliary battery 30 is equal to or greater than the second threshold (step S202, Yes), the process proceeds to step S203. On the other hand, if the solar charging system 1 determines that the amount of stored power (charge amount) in the auxiliary battery 30 is less than the second threshold (step S202, No), the process proceeds to step S204.

[0023] (Step S203) The solar charging system 1 performs pumping charging, outputting the power of the auxiliary battery 30 and the power generated by the solar power generation module 10 to the drive battery 20. Fig. 4 shows an example of a power transfer path when power is supplied from the solar power generation module 10 and the auxiliary battery 30 to the drive battery 20 (pumping charging is performed). When performing this pumping charging, control is performed based on the boost efficiency of the bidirectional DC-DC converter 40 so that power with a high boost efficiency is input to the bidirectional DC-DC converter 40. In the example of Fig. 3, power X or more with a boost efficiency of high efficiency b or higher is input to the bidirectional DC-DC converter 40.

[0024] Furthermore, in this pumping charging, the output power of the auxiliary battery 30 is varied in accordance with fluctuations in the power generated by the solar power generation module 10 so that the input power of the bidirectional DC-DC converter 40 is equal to or greater than power X. For example, if power X is secured by the power generated by the solar power generation module 10 (W1) and the output power of the auxiliary battery 30 (W2) (X=W1+W2), and the power generated by the solar power generation module 10 drops to "W1-W3" due to a change in the amount of solar radiation, the output power of the auxiliary battery 30 is increased to "W2+W3." As a result, the input power of the bidirectional DC-DC converter 40 becomes (W1-W3)+(W2+W3)=W1+W2, and power X can be secured with high boost efficiency.

[0025] When the solar charging system 1 outputs the power of the auxiliary battery 30 and the power generated by the solar power generation module 10 to the drive battery 20 (pumping charge), this charging control ends.

[0026] (Step S204) The solar charging system 1 performs solar charging by outputting the power generated by the solar power generation module 10 to the auxiliary battery 30. Figure 5 shows an example of a power transfer path when power is supplied from the solar power generation module 10 to the auxiliary battery 30. In this case, a request for power transfer (pumping charging) from the auxiliary battery 30 to the drive battery 20 is denied. When the solar charging system 1 outputs the power generated by the solar power generation module 10 to the auxiliary battery 30 (normal charging), this charging control ends.

[0027] (Step S205) The solar charging system 1 ends this charging control without outputting the power generated by the solar power generation module 10. In this case, too, the request for power transfer (pumping charging) from the auxiliary battery 30 to the drive battery 20 is denied.

[0028] <Actions and Effects> As described above, according to the solar charging system 1 according to one embodiment of the present disclosure, when the generated power output by the solar power generation module 10 is equal to or greater than the first threshold and the amount of stored power in the auxiliary battery 30 is equal to or greater than the second threshold, power is transferred (pumping charging) from the solar power generation module 10 and the auxiliary battery 30 to the drive battery 20.

[0029] This control can improve the charging efficiency of the auxiliary battery 30 power and solar-generated power during pumping charging. It also can suppress deterioration and heat generation of the auxiliary battery 30. Furthermore, it can reduce the automatic time of the electronic control unit (ECU) used to execute charging control.

[0030] Furthermore, according to the solar charging system 1 according to an embodiment of the present disclosure, input power that increases the boost efficiency of the bidirectional DC-DC converter 40 is output from the solar power generation module 10 and the auxiliary battery 30 to the drive battery 20. Furthermore, the solar charging system 1 according to this embodiment increases or decreases the output power of the auxiliary battery 30 in accordance with an increase or decrease in the power generated by the solar power generation module 10, thereby maintaining the input power that increases the boost efficiency of the bidirectional DC-DC converter 40.

[0031] This control can further improve the charging efficiency of the auxiliary battery power and the solar-generated power during pumping charging.

[0032] 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 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]

[0033] The solar charging system of the present disclosure can be used in vehicles equipped with solar panels. [Explanation of symbols]

[0034] 1 Solar charging system 10 Solar power generation module 20 Drive battery 30 Auxiliary battery 40 Bidirectional DC / DC converter 100 Auxiliary load

Claims

1. A solar charging system mounted on a vehicle, a power generation module using a solar panel; an auxiliary battery that stores the power generated by the power generation module; a drive battery used to drive the vehicle; a control unit provided between the drive battery and the auxiliary battery to control power transfer between the two batteries, The control unit supplying power to the drive battery from both the power generation module and the auxiliary battery when the generated power output by the power generation module is equal to or greater than a first threshold and the amount of power stored in the auxiliary battery is equal to or greater than a second threshold; increasing or decreasing the power output from the auxiliary battery in accordance with a change in the power generated by the power generation module so that the power supplied to the drive battery becomes a predetermined value; Solar charging system.

2. the control unit supplies power from the power generation module to the auxiliary battery when the generated power output by the power generation module is equal to or greater than the first threshold and the amount of power stored in the auxiliary battery is less than the second threshold. The solar charging system according to claim 1 .

3. the control unit does not output power from the power generation module when the generated power output by the power generation module is less than the first threshold value. The solar charging system according to claim 1 .

4. The control unit includes a DC-DC converter that boosts the power input from the power generation module and the auxiliary battery and converts it into power output to the drive battery, The predetermined value is set to a power at which the boost efficiency of the DC-DC converter is high. The solar charging system according to claim 1 .

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