Solar charging system

Abstract

To provide a solar charging system capable of suppressing deterioration progress of an accessory battery and capable of reducing a load on a component required for changing over a charging state.SOLUTION: A solar charging system mounted on a vehicle comprises a solar panel, an accessory battery, a high-voltage battery, and a controlling unit for controlling changeover between a first charging state for charging the accessory battery with power generated by the solar panel and a second charging state for charging the high-voltage battery with power generated by the solar panel. The controlling unit performs control to the first charging state when the average power generation amount of the solar panel in a past predetermined period is equal to or lower than a predetermined threshold and performs control to the second charging state when the amount exceeds the predetermined threshold.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 that switches between a first mode in which the process of charging the auxiliary battery with power generated by the solar panel and the process of indirectly charging the high-voltage battery with power stored in the auxiliary battery are repeated depending on the amount of power stored in the auxiliary battery, and a second mode in which the power generated by the solar panel is directly charged to the high-voltage battery, based at least on the power generated by the solar panel. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2019-050713 Summary of the Invention [Problem to be solved by the invention]

[0004] In the solar charging system described in Patent Document 1, when the power generated by the solar panel fluctuates above and below a threshold due to factors such as the influence of sunlight, frequent switching between the first and second modes occurs. Such frequent switching between modes (charging states) is undesirable because it accelerates the deterioration of the auxiliary battery and increases the load on the components required for mode switching.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a solar charging system that can suppress the progression of deterioration of the auxiliary battery and reduce the load on the components required to switch the charging state. [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 solar panel, an auxiliary battery, a high-voltage battery, and a control unit that controls switching between a first charging state in which the auxiliary battery is charged with power generated by the solar panel and a second charging state in which the high-voltage battery is charged with power generated by the solar panel, wherein the control unit controls the solar charging system to the first charging state if the average power generation amount of the solar panel over a predetermined period in the past is below a predetermined threshold, and controls the solar charging system to the second charging state if the average power generation amount of the solar panel over a predetermined period in the past is above a predetermined threshold. [Effects of the Invention]

[0007] According to the solar charging system disclosed herein, the charging state is switched based on the average value rather than the instantaneous value of the power generation amount of the solar panel, which makes it possible to suppress the deterioration of the auxiliary battery and reduce the load on the components required to switch the charging state. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram of a solar charging system according to an embodiment of the present disclosure. [Figure 2] Processing flowchart of charging control (standard) executed by the solar charging system [Figure 3] Processing flowchart of charging control (application) executed by the solar charging system [Figure 4] A diagram explaining the power path when charging the auxiliary battery. [Figure 5] Diagram explaining the power path when charging a high-voltage battery DETAILED DESCRIPTION OF THE INVENTION

[0009] The solar charging system according to the present disclosure sets the standard state in which the power generated by the solar panel charges the auxiliary battery, and controls the system to switch the power generated by the solar panel to charging the high-voltage battery only when the average power generation amount over a predetermined period of time in the past exceeds a reference value. This makes it possible to suppress the phenomenon in which the charging state frequently switches due to the effects of solar radiation, thereby suppressing the deterioration of the auxiliary battery and reducing the load on the components required to switch the charging state. 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 100 according to an embodiment of the present disclosure. The solar charging system 100 shown in Fig. 1 includes a solar power generation module 110, a high-voltage battery 120, an auxiliary battery 130, and a control unit 140.

[0011] The solar charging system 100 can be installed in vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs), for example.

[0012] Solar power generation module 110 is a power generation device that generates electricity when exposed to sunlight, and outputs the generated power to auxiliary battery 130 and control unit 140 connected to solar power generation module 110. This solar power generation module 110 is configured to include a solar panel 111, which is an assembly of solar battery cells, and an MPPT 112 that controls the power generated by solar panel 111 using a maximum power point tracking method. The power generated by solar panel 111 is calculated from measurements of sensors and measuring instruments (not shown).

[0013] The high-voltage battery 120 is a secondary battery, such as a lithium-ion battery, that is configured to be rechargeable. The high-voltage battery 120 is connected to a main device (not shown) for driving the vehicle and can supply the power necessary for the operation of the main device. The high-voltage battery 120 is connected to the solar power generation module 110 via a control unit 140 so that it can be charged with power generated by a solar panel 111 of the solar power generation module 110. The high-voltage battery 120 is also connected to the auxiliary battery 130 via the control unit 140 so that it can supply its own stored power to the auxiliary battery 130 and can be charged with power stored in the auxiliary battery 130. The high-voltage battery 120 is, for example, a drive battery with a higher rated voltage than the auxiliary battery 130.

[0014] The auxiliary battery 130 is a secondary battery configured to be rechargeable, such as a lithium-ion battery or a lead-acid battery. The auxiliary battery 130 is connected to auxiliary devices (not shown) other than the above-mentioned main devices, and can supply the power necessary for the operation of the auxiliary devices. The auxiliary battery 130 is connected to the solar power generation module 110 so as to be rechargeable with power generated by the solar panel 111 of the solar power generation module 110. The auxiliary battery 130 is also connected to the high-voltage battery 120 via the control unit 140 so as to be rechargeable with power stored in the high-voltage battery 120 and to be able to supply its own stored power to the high-voltage battery 120. The amount of power stored in the auxiliary battery 130 and the inflow and outflow currents are monitored by sensors, measuring instruments, etc. (not shown).

[0015] The control unit 140 is a bidirectional power converter that can convert input power into power of a predetermined voltage and output it, 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 140 is connected to the solar power generation module 110 and the auxiliary battery 130, and the other end (secondary side) is connected to the high-voltage battery 120. The control unit 140 can supply (pumping charge) power output from the solar power generation module 110 and the auxiliary battery 130 connected to one end to the high-voltage battery 120 connected to the other end. During this power supply, the control unit 140 performs a boost operation to boost the voltage of the power input to one end to generate an output voltage at the other end. The control unit 140 can also supply (pumping charge) power from the high-voltage battery 120 connected to the other end to the auxiliary battery 130 connected to one end. During this power supply, the control unit 140 performs a step-down operation to lower the voltage of the power input to the other end to generate an output voltage at one end.

[0016] [control] Next, with further reference to FIGS. 2 to 5, the control performed in the solar charging system 100 according to this embodiment will be described.

[0017] (1) Standard control Fig. 2 is a flowchart illustrating the processing procedure of standard solar charging control executed by the solar charging system 100. The standard solar charging control illustrated in Fig. 2 is repeatedly performed while the solar charging system 100 is operating.

[0018] (Step S201) The solar charging system 100 acquires the power generation state of the solar panel 111 in the solar power generation module 110. An example of the power generation state of the solar panel 111 is the amount of power generated by the solar panel 111 per predetermined unit time (hereinafter referred to as "power generation amount of the solar panel 111"). The power generation amount of the solar panel 111 acquired by the solar charging system 100 is stored and accumulated in a predetermined memory (not shown) or the like. When the power generation amount of the solar panel 111 is acquired by the solar charging system 100, the process proceeds to step S201.

[0019] (Step S202) The solar charging system 100 calculates the average amount of power generated by the solar panel 111 over a predetermined period in the past. This average amount of power generated can be obtained by averaging the amounts of power generated by the solar panel 111 over the predetermined period in the past. The predetermined period in the past is a period going back a predetermined time (for example, 10 minutes, 30 minutes, or 1 hour) from the current time point at which this calculation is performed. If the average amount of power generated cannot be calculated (such as in the initial state immediately after control is started), the solar charging system 100 waits to calculate the average amount of power generated until it can obtain the amount of power generated by the solar panel 111 in the past that is required for the calculation. Once the solar charging system 100 has calculated the average amount of power generated by the solar panel 111, the process proceeds to step S202.

[0020] (Step S203) The solar charging system 100 determines whether the average amount of power generated by the solar panel 111 is equal to or less than a predetermined threshold. This determination is made in order to determine an appropriate charging destination (supply destination) of the power generated by the solar panel 111. The predetermined threshold is set to a value indicating that the solar panel 111 is generating a large amount of power (or a large amount of electric power) that can be supplied to the high-voltage battery 120. If the solar charging system 100 determines that the average amount of power generated by the solar panel 111 is equal to or less than the threshold (Yes in step S203), the process proceeds to step S204. On the other hand, if the solar charging system 100 determines that the average amount of power generated by the solar panel 111 exceeds the threshold (No in step S203), the process proceeds to step S205.

[0021] (Step S204) The solar charging system 100 controls the supply of power from the solar power generation module 110 to the auxiliary battery 130 to charge the auxiliary battery 130 (first charging state). In this first charging state, as shown in Fig. 4, the solar charging system 100 does not operate the control unit 140 (bidirectional DDC) in principle. However, when charging the high-voltage battery 120 with power from the auxiliary battery 130 (pumping charging), the control unit 140 (bidirectional DDC) is operated. When the solar charging system 100 performs control to charge the auxiliary battery 130, the process proceeds to step S201.

[0022] (Step S205) The solar charging system 100 controls the supply of power from the solar power generation module 110 to the high-voltage battery 120 to charge the high-voltage battery 120 (second charging state). In this second charging state, as shown in Fig. 5, the solar charging system 100 activates the control unit 140 (bidirectional DDC). This causes the high-voltage battery 120 to be directly charged with power generated by the solar panel 111, without going through the auxiliary battery 130. When the solar charging system 100 controls the charging of the high-voltage battery 120, the process proceeds to step S201.

[0023] (2) Application control Fig. 3 is a flowchart illustrating the processing procedure of the applied solar charging control executed by the solar charging system 100. The applied solar charging control illustrated in Fig. 3 is repeatedly performed while the solar charging system 100 is operating.

[0024] This applied solar charging control is obtained by adding the processing of steps S301 and S302 between steps S203 and S204 of the above-mentioned standard solar charging control (FIG. 2). Below, we will explain the processing in the applied solar charging control that differs from the standard solar charging control, assuming that the processing proceeds to step S301 when the average power generation amount of the solar panel 111 is equal to or less than the threshold (step S203, Yes).

[0025] (Step S301) The solar charging system 100 determines whether the auxiliary battery 130 is capable of receiving electric power. This determination is made to ascertain whether the auxiliary battery 130 is in a chargeable state. For example, if the amount of stored power in the auxiliary battery 130 is less than a predetermined value (fully charged state), it is determined that electric power is capable of being received. Also, if an abnormality is found in the auxiliary battery 130, such as the temperature being higher than a predetermined value, it is determined that electric power is not capable of being received. Furthermore, if the input / output power is limited to prevent deterioration of the auxiliary battery 130, it is determined whether electric power is capable of being received or not based on the limited power. Such a state of the auxiliary battery 130 is determined based on physical quantities detected by sensors, measuring instruments, etc. If the solar charging system 100 determines that the auxiliary battery 130 is capable of receiving electric power (Yes in step S301), the process proceeds to step S302. On the other hand, if the solar charging system 100 determines that the auxiliary battery 130 cannot accept electric power (step S301, No), the process proceeds to step S205.

[0026] (Step S302) The solar charging system 100 determines whether the auxiliary battery 130 is in a degraded state. This degraded state refers to a state in which the auxiliary battery 130 is presumed to be degraded, such as a state in which the full charge capacity of the auxiliary battery 130 is extremely low or a state in which the internal resistance of the auxiliary battery 130 is outside a reference value. If the solar charging system 100 determines that the auxiliary battery 130 is not in a degraded state (Yes in step S302), the process proceeds to step S204. On the other hand, if the solar charging system 100 determines that the auxiliary battery 130 is in a degraded state (No in step S302), the process proceeds to step S205.

[0027] <Actions and Effects> As described above, the solar charging system 100 according to one embodiment of the present disclosure performs control to charge the auxiliary battery 130 with the power generated by the solar panel 111 when the average power generation amount of the solar panel 111 over a predetermined period in the past is below a predetermined threshold, and performs control to directly charge the high-voltage battery 120 with the power generated by the solar panel 111 without going through the auxiliary battery 130 when the average power generation amount of the solar panel 111 over a predetermined period in the past exceeds the predetermined threshold.

[0028] This control determines whether to switch the charging state (where to charge) based on an average value over a predetermined period, rather than an instantaneous value of the amount of power generated by the solar panel 111, and therefore can prevent frequent switching of the charging state due to sudden changes in solar radiation, etc. This can suppress the progression of deterioration of the auxiliary battery 130 and reduce the load on components required for switching the charging state (for example, a relay inserted between the control unit 140 and the high-voltage battery 120).

[0029] 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 solar charging control method, a program for that method, a computer-readable non-transitory storage medium storing the program, and a vehicle equipped with a solar charging system. [Industrial Applicability]

[0030] The solar charging system of the present disclosure can be used in vehicles equipped with solar panels. [Explanation of symbols]

[0031] 100 Solar Charging System 110 Solar power generation module 111 Solar Panel 112 MPPT 120 High Voltage Battery 130 Auxiliary Battery 140 Control unit (bidirectional DDC)

Claims

1. A solar charging system mounted on a vehicle, Solar panels and An auxiliary battery; A high-voltage battery, a control unit that controls switching between a first charging state in which the auxiliary battery is charged with power generated by the solar panel and a second charging state in which the high-voltage battery is charged with power generated by the solar panel, the control unit controls the solar panel to the first charging state when an average amount of power generated by the solar panel over a predetermined period in the past is equal to or less than a predetermined threshold, and controls the solar panel to the second charging state when the average amount of power generated by the solar panel over a predetermined period in the past is greater than the predetermined threshold. Solar charging system.

2. the control unit controls the auxiliary battery to the second charging state if the auxiliary battery cannot accept power even if the average amount of power generated by the solar panel during the past predetermined period is equal to or less than the predetermined threshold. The solar charging system according to claim 1 .

3. the control unit controls the auxiliary battery to the second charging state if the auxiliary battery is in a predetermined deteriorated state even if the average amount of power generated by the solar panel during the past predetermined period is equal to or less than the predetermined threshold. The solar charging system according to claim 1 .

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