Solar charging system

Abstract

To provide a solar charging system in which the charging efficiency of power generated by a solar panel during a parking time can be improved.SOLUTION: A solar charging system installed in a vehicle, includes a solar panel, a driving battery that is used to drive the vehicle, an auxiliary battery that supplies power to an on-vehicle device that works during parking, and a control unit that controls power of the solar panel, the driving battery, and the auxiliary battery. During the parking, the control unit performs control so as to prevent concurrent execution of a charging process of supplying power generated by the solar panel to the driving battery, and a discharging process of supplying the power of the driving battery to an auxiliary system including the auxiliary battery and the on-vehicle device.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 machine system to derive the actual power generated by the solar panel, and if the derived actual generated power is equal to or greater than a specified value, further charges a drive battery with the generated 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] Generally, when a vehicle is parked, the power supply to the devices that operate the services provided during parking is performed from the auxiliary battery. Also, in order to prevent the auxiliary battery from discharging, control to supply the power of the drive battery to the devices that operate the services provided during parking is also performed as necessary.

[0005] Here, if the process of charging the drive battery with the generated power of the solar panel and the process of supplying the power of the drive battery to the devices that operate the services provided during parking are controlled independently, the chances of power loss increase in a DC-DC converter that steps up / down the voltage, etc., resulting in problems such as a decrease in charging efficiency. Therefore, there is room for further consideration regarding the charging method of solar-generated power implemented in the solar charging system during parking.

[0006] The present disclosure has been made in view of the above problems, and an object thereof is to provide a solar charging system or the like that can improve the charging efficiency of electric power generated by a solar panel during parking.

Means for Solving the Problems

[0007] In order to solve the above problems, one aspect of the disclosed technology is a solar charging system mounted on a vehicle, including a solar panel, a driving battery used for driving the vehicle, an auxiliary battery that supplies power to in-vehicle devices operating during parking, and a control unit that controls the power of the solar panel, the driving battery, and the auxiliary battery. The control unit controls so as not to simultaneously execute a charging process of supplying the generated power of the solar panel to the driving battery and a discharging process of supplying the power of the driving battery to an auxiliary system including the auxiliary battery and in-vehicle devices during parking.

Effects of the Invention

[0008] According to the solar charging system of the present disclosure, the electric power obtained by boosting the generated power of the solar panel and charging the driving battery is not directly stepped down and supplied to in-vehicle devices. Therefore, the charging efficiency of the electric power generated by the solar panel during parking can be improved.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2A

Figure 2B

Figure 3

Figure 4

Mode for Carrying Out the Invention

[0010] The solar charging system according to the present disclosure controls so that charging of the drive battery using the electric power generated by the solar panel during parking and taking out electric power from the drive battery to the auxiliary system due to power reduction of the auxiliary battery are not executed in parallel. Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0011] <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. The solar charging system 1 illustrated in FIG. 1 includes a solar panel 10, a solar DDC 20, a high-voltage DDC 30, an auxiliary DDC 40, a drive battery 50, an auxiliary battery 60, an in-parking service DDC 70, and a control unit 80. The auxiliary DDC 40, the auxiliary battery 60, and the in-parking service DDC 70 are connected to the in-parking operating device 100. This solar charging system 1 can be mounted on a vehicle or the like.

[0012] The solar panel 10 is a power generation device that generates power by receiving sunlight, and is typically a solar cell module that is an aggregate of solar cells. This solar panel 10 can be installed, for example, on the roof of a vehicle (solar roof). The solar panel 10 is connected to the solar DDC 20, and the power generated by the solar panel 10 is output to the solar DDC 20. Note that the number of solar panels 10 installed in a vehicle is not limited to one and may be plural.

[0013] The solar DDC 20 is a DCDC converter for supplying the power generated by the solar panel 10 to the high-voltage DDC 30 and the auxiliary DDC 40. This solar DDC 20 can convert (step up or step down) the output voltage of the solar panel 10, which is the input voltage, to a predetermined voltage and output it to the high-voltage DDC 30 and the auxiliary DDC 40 when supplying power.

[0014] The high-voltage DDC30 is a DCDC converter for supplying the power output by the solar DDC20 to the driving battery 50. This high-voltage DDC30 can boost the output voltage of the solar DDC20, which is the input voltage, to a predetermined voltage and output it to the driving battery 50 during power supply.

[0015] The accessory DDC40 is a DCDC converter for supplying the power output by the solar DDC20 to the accessory battery 60 and the in-vehicle operating equipment 100 during parking. This accessory DDC40 can step down the output voltage of the solar DDC20, which is the input voltage, to a predetermined voltage and output it to the accessory battery 60 and the in-vehicle operating equipment 100 during power supply.

[0016] The above-described solar DDC20, high-voltage DDC30, and accessory DDC40 typically constitute a solar ECU (Electronic Control Unit) 90. When a plurality of solar panels 10 are installed in a vehicle, a plurality of solar DDC20s may be provided in parallel to individually control each solar panel 10, as in the solar charging system 2 illustrated in FIG. 4. Further, the solar ECU 90 may be configured integrally with the solar panel 10 or may be integrally configured with other power train components.

[0017] The driving battery 50 is a secondary battery configured to be chargeable and dischargeable, such as a lithium-ion battery or a nickel-metal hydride battery. This driving battery 50 is connected to the high-voltage DDC30 so as to be chargeable by the power output by the high-voltage DDC30. The driving battery 50 mounted on the vehicle is a battery that can supply the power required for the operation of main devices (not shown) for driving the vehicle, such as a starter motor and an electric motor. The driving battery 50 is set to have a higher rated voltage than the accessory battery 60.

[0018] The auxiliary battery 60 is a secondary battery configured to be chargeable and dischargeable, such as a lithium-ion battery or a lead-acid battery. The auxiliary battery 60 is connected to the auxiliary DDC 40 so as to be chargeable by the power output from the auxiliary DDC 40. The auxiliary battery 60 mounted on the vehicle supplies power required for the operation of auxiliary devices (not shown) other than those for driving the vehicle, such as lights such as headlamps and interior lights, air conditioners such as heaters and coolers, and devices for autonomous driving and advanced driver assistance, and power required for the operation of the in-vehicle operating device 100 described later. The auxiliary battery 60 is set to a rated voltage (for example, 12V) lower than that of the driving battery 50. Note that the system on the output side of the auxiliary DDC 40 to which the auxiliary battery 60, auxiliary devices (not shown), the in-vehicle operating device 100, etc. are connected is hereinafter referred to as the "auxiliary system".

[0019] The in-vehicle service DDC 70 is a DCDC converter for supplying the power stored in the driving battery 50 to at least the in-vehicle operating device 100 during parking. The in-vehicle service DDC 70 can also charge the auxiliary battery 60 with the power of the driving battery 50 when the auxiliary battery 60 needs to be charged. The in-vehicle service DDC 70 can step down the output voltage of the driving battery 50, which is the input voltage, to a predetermined voltage and output it to the in-vehicle operating device 100 (and the auxiliary battery 60, etc.) during power supply.

[0020] In this embodiment, a configuration in which the in-vehicle service DDC 70 is provided as an independent equipment dedicated for parking has been described. However, it is also possible to omit the configuration of the in-vehicle service DDC 70 by imparting the functions executed by the in-vehicle service DDC 70 to other existing DCDC converters.

[0021] The control unit 80 controls the power of the solar panel 10, the driving battery 50, and the auxiliary battery 60 by controlling at least the high-voltage DDC 30, the auxiliary DDC 40, and the in-parking service DDC 70. Specifically, the control unit 80 controls the power supply from the solar panel 10 to the driving battery 50 by controlling the operating state of the high-voltage DDC 30. Further, the control unit 80 controls the power supply from the solar panel 10 to the auxiliary battery 60 and the in-parking operating equipment 100 by controlling the operating state of the auxiliary DDC 40. Also, the control unit 80 controls the power supply from the driving battery 50 to the in-parking operating equipment 100 (and the auxiliary battery 60, etc.) by controlling the operating state of the in-parking service DDC 70.

[0022] Note that this control unit 80 may be realized as a function of an HV-ECU (not shown) that performs hybrid control of the vehicle, may be realized as a function of the solar ECU 90, or may be realized by an ECU other than these ECUs. The ECU that realizes the control unit 80 typically includes a processor, a memory, and an input / output interface, etc., and the processor can read and execute a program stored in the memory to perform various controls described above.

[0023] The in-parking operating equipment 100 is in-vehicle equipment for executing a predetermined in-parking service provided to a user or the like when the vehicle is in a parked state. This in-parking operating equipment 100 can operate by the power supplied from the solar panel 10 or the auxiliary battery 60. Examples of the in-parking operating equipment 100 include a drive recorder (DR).

[0024] [Control] Next, with further reference to FIGS. 2A and 2B, the control executed by the solar charging system 1 will be described. FIGS. 2A and 2B are flowcharts for explaining the charging control processes executed by the control unit 80 and the solar ECU 90 of the solar charging system 1. The process in FIG. 2A and the process in FIG. 2B are connected by connectors X and Y.

[0025] The charging control illustrated in FIGS. 2A and 2B starts, for example, when the solar ECU 90 that has stopped (slept) some or all of its functions wakes up the stopped functions due to the solar panel 10 being able to generate electricity by sunlight irradiation, such as when the vehicle is parked.

[0026] (Step S201) The solar ECU 90 acquires the generated power Wgen, which is the power generated by the solar panel 10. This generated power Wgen can be derived from the voltage and current output by the solar panel 10. Note that the generated power Wgen may be notified to the control unit 80. When the solar ECU 90 acquires the generated power Wgen of the solar panel 10, the process proceeds to step S202.

[0027] (Step S202) The solar ECU 90 determines whether the generated power Wgen of the solar panel 10 exceeds a predetermined threshold value Wsol. This determination is made to determine whether the solar panel 10 is generating enough power to enable efficient charging control. For example, if the generated power Wgen of the solar panel 10 is less than the power required for the charging operation of the solar charging system 1, discharge from the auxiliary battery 60 will occur, and more battery power will be consumed than the power that can be obtained from solar power generation, making the charging control meaningless. Therefore, the threshold value Wsol can be set to a value equal to or greater than the power at which charging control is possible without discharge from the auxiliary battery 60.

[0028] If the solar ECU 90 determines that the generated power Wgen exceeds the threshold value Wsol (Wgen > Wsol) (step S202, yes), the process proceeds to step S204. On the other hand, if the solar ECU 90 determines that the generated power Wgen does not exceed the threshold value Wsol (Wgen ≤ Wsol) (step S202, no), the process proceeds to step S203.

[0029] (Step S203) Since the solar ECU 90 cannot perform efficient charging control using the generated power Wgen of the solar panel 10, it stops the operation of some or all of the predetermined functions and enters the sleep state. Thereby, this charging control ends.

[0030] (Step S204) The solar ECU 90 starts power generation by the solar panel 10. That is, the solar ECU 90 starts outputting the generated power Wgen of the solar panel 10 to the auxiliary battery 60 and the like. For this power generation, well-known maximum power point tracking (MPPT) control or the like is used. When the solar ECU 90 starts power generation by the solar panel 10, the process proceeds to Step S205.

[0031] (Step S205) The control unit 80 acquires the processing power Waux consumed in the process of charging the auxiliary battery 60 (hereinafter referred to as "solar charging process"). More specifically, the processing power Waux is the sum of the power required for the control operations of the ECU and the like involved in the execution of the solar charging process and the power for charging the auxiliary battery 60. This processing power Waux can be derived from the outflow current and output voltage of the auxiliary battery 60 detected by the control unit 80 and the like. Also, the processing power Waux is notified to the solar ECU 90. When the control unit 80 acquires the processing power Waux, the process proceeds to Step S206.

[0032] (Step S206) The control unit 80 determines whether or not the in-vehicle service is activated while the vehicle is parked. The activation of this in-vehicle service while parked means that at least the in-vehicle operating device 100 is operating.

[0033] When the control unit 80 determines that the in-vehicle service is activated while parked (Step S206, Yes), the process proceeds to Step S209. On the other hand, when the control unit 80 determines that the in-vehicle service is not activated while parked (Step S206, No), the process proceeds to Step S207.

[0034] (Step S207) The control unit 80 and the solar ECU 90 supply the auxiliary power Waux from the generated power Wgen of the solar panel 10 to the auxiliary system. When the auxiliary power Waux is supplied to the auxiliary system by the control unit 80 and the solar ECU 90, the process proceeds to step S208.

[0035] (Step S208) The control unit 80 and the solar ECU 90 supply the surplus power Wrem1 that is not supplied to the auxiliary system from the generated power Wgen of the solar panel 10 to the drive battery 50. This surplus power Wrem1 is the power obtained by subtracting the auxiliary power Waux from the generated power Wgen (Wrem1 = Wgen - Waux). When the surplus power Wrem1 is supplied to the drive battery 50 by the control unit 80 and the solar ECU 90, the process proceeds to step S209.

[0036] (Step S209) The control unit 80 acquires the power consumption Wpark consumed in the parking service. Specifically, the power consumption Wpark is the power consumed by the operating equipment 100 during parking. This power consumption Wpark may be given in advance as a fixed value, or may be derived from the outflow current and output voltage of the auxiliary battery 60 detected by the control unit 80 or the like. Also, the power consumption Wpark is notified to the solar ECU 90. When the power consumption Wpark is acquired by the control unit 80, the process proceeds to step S210.

[0037] (Step S210) The solar ECU 90 determines whether the generated power Wgen of the solar panel 10 is equal to or greater than the power consumption Wpark consumed in the parking service. This determination is made to determine whether the parking service can be operated only by the supply of the generated power Wgen.

[0038] When the solar ECU 90 determines that the generated power Wgen is equal to or greater than the power consumption Wpark (Wgen ≧ Wpark) (step S210, yes), the process proceeds to step S211. On the other hand, when the solar ECU 90 determines that the generated power Wgen is less than the power consumption Wpark (Wgen < Wpark) (step S210, no), the process proceeds to step S213.

[0039] (Step S211) The control unit 80 and the solar ECU 90 supply the power obtained by adding the processing power Waux and the power consumption Wpark (=Waux + Wpark) to the auxiliary system from the generated power Wgen of the solar panel 10. When the power obtained by adding the power consumption Wpark to the processing power Waux is supplied to the auxiliary system by the control unit 80 and the solar ECU 90, the process proceeds to step S212.

[0040] (Step S212) The control unit 80 and the solar ECU 90 supply the surplus power Wrem2 that is not supplied to the auxiliary system to the driving battery 50 from the generated power Wgen of the solar panel 10. This surplus power Wrem2 is the power obtained by subtracting the processing power Waux and the power consumption Wpark from the generated power Wgen (Wrem2 = Wgen - (Waux + Wpark)). When the surplus power Wrem2 is supplied to the driving battery 50 by the control unit 80 and the solar ECU 90, the process proceeds to step S201.

[0041] (Step S213) The control unit 80 and the solar ECU 90 supply the generated power Wgen of the solar panel 10 to the auxiliary system. When the generated power Wgen is supplied to the auxiliary system by the control unit 80 and the solar ECU 90, the process proceeds to step S214.

[0042] (Step S214) The control unit 80 supplies the insufficient power Wlack, which cannot be covered only by the generated power Wgen of the solar panel 10 among the power required for the auxiliary equipment system, from the drive battery 50 to the auxiliary equipment system via the parking service DDC 70. This insufficient power Wlack is the power obtained by subtracting the generated power Wgen of the solar panel 10 from the power obtained by adding the processing power Waux required for the solar charging process and the power consumption Wpark consumed during parking service (Wlack = (Waux + Wpark) - Wgen). When the control unit 80 supplies the insufficient power Wlack from the drive battery 50 to the auxiliary equipment system, the process proceeds to step S201.

[0043] In this way, by determining the required power at each location and appropriately controlling it, it is possible to prevent the charging process of supplying the generated power of the solar panel 10 to the drive battery 50 and the discharging process of supplying the power of the drive battery 50 to the equipment 100 in operation during parking from being executed simultaneously. Thereby, the charging efficiency of the power generated by the solar panel 10 during parking can be improved.

[0044] [Application Example] In FIGS. 2A and 2B described above, the charging control based on power control (current indication) was explained. In this application example, with reference to FIG. 3, the charging control based on voltage control (voltage indication) will be explained. FIG. 3 is a flowchart for explaining the processing of the charging control of the application example executed by the control unit 80 and the solar ECU 90 of the solar charging system 1.

[0045] The charging control of the application example illustrated in FIG. 3 starts, for example, when the solar ECU 90, which has stopped (slept) some or all of its functions while the vehicle is parked, wakes up (activates) the stopped functions when the solar panel 10 can generate power due to sunlight irradiation.

[0046] (Step S301) The solar ECU 90 acquires the generated power Wgen of the solar panel 10. When the generated power Wgen is acquired by the solar ECU 90, the process proceeds to step S302.

[0047] (Step S302) The solar ECU 90 determines whether the generated power Wgen of the solar panel 10 exceeds a predetermined threshold value Wsol. This determination is made to determine whether the solar panel 10 is generating sufficient power to enable efficient charging control. The threshold value Wsol is as described above.

[0048] If the solar ECU 90 determines that the generated power Wgen exceeds the threshold value Wsol (Wgen > Wsol) (step S302, yes), the process proceeds to step S304. On the other hand, if the solar ECU 90 determines that the generated power Wgen does not exceed the threshold value Wsol (Wgen ≤ Wsol) (step S302, no), the process proceeds to step S303.

[0049] (Step S303) Since the solar ECU 90 cannot perform efficient charging control using the generated power Wgen of the solar panel 10, it stops the operation of a predetermined part or all of the functions and puts them into sleep. Thereby, this charging control ends.

[0050] (Step S304) The solar ECU 90 starts generating power by the solar panel 10. That is, the solar ECU 90 starts outputting the generated power Wgen to the auxiliary battery 60 and the like. For this power generation, well-known maximum power point tracking (MPPT) control and the like are used. When the solar ECU 90 starts generating power by the solar panel 10, the process proceeds to step S305.

[0051] (Step S305) The control unit 80 and the solar ECU 90 control the output voltage of the auxiliary DDC 40 to be the target output voltage Vtgt1, and supply the generated power Wgen of the solar panel 10 to the auxiliary system. The target output voltage Vtgt1 is appropriately set based on the rated voltage of the auxiliary battery 60 and the like. When the auxiliary DDC 40 is controlled at the target output voltage Vtgt1 by the control unit 80 and the solar ECU 90 and the generated power Wgen is supplied to the auxiliary system, the process proceeds to step S306.

[0052] (Step S306) The control unit 80 determines whether the voltage actually output by the auxiliary battery 60 exceeds a predetermined voltage V based on the control by the target output voltage Vtgt1. This determination is made to determine whether the auxiliary battery 60 needs to be charged. Therefore, the voltage V is appropriately set based on the rated voltage of the auxiliary battery 60 and the like.

[0053] When the control unit 80 determines that the output voltage of the auxiliary battery 60 exceeds the predetermined voltage V (step S306, yes), the process proceeds to step S307. On the other hand, when the control unit 80 determines that the output voltage of the auxiliary battery 60 does not exceed the predetermined voltage V (step S306, no), the process proceeds to step S308.

[0054] (Step S307) The control unit 80 and the solar ECU 90 control the output voltage of the parking service DDC 70 to be the target output voltage Vtgt2, and supply the power of the driving battery 50 to the auxiliary system. The target output voltage Vtgt2 is appropriately set based on the rated voltage of the auxiliary battery 60, the target output voltage Vtgt1, and the like. When the parking service DDC 70 is controlled at the target output voltage Vtgt2 by the control unit 80 and power is supplied from the driving battery 50 to the auxiliary system, the process proceeds to step S301.

[0055] (Step S307) The control unit 80 and the solar ECU 90 supply the surplus power Wrem, which is not supplied to the auxiliary equipment system, among the generated power Wgen of the solar panel 10, to the driving battery 50. This surplus power Wrem is the power obtained by subtracting the power W output to the auxiliary equipment system based on the control by the target output voltage Vtgt1 from the generated power Wgen (Wrem = Wgen - W). When the surplus power Wrem is supplied to the driving battery 50 by the control unit 80 and the solar ECU 90, the process proceeds to step S301.

[0056] As in this application example, the charging efficiency of the power generated by the solar panel 10 during parking can also be improved by voltage control.

[0057] <Function and Effect> As described above, according to the solar charging system 1 according to an embodiment of the present disclosure, during parking, the charging process of supplying the generated power Wgen of the solar panel 10 to the driving battery 50 and the discharging process of supplying the power of the driving battery 50 to the auxiliary equipment system including the in-vehicle operating equipment 100 during parking are controlled so as not to be executed simultaneously.

[0058] By this control, power transfer with many losses, such as boosting the generated power Wgen of the solar panel 10 and then directly bucking the power charged to the driving battery 50 and supplying it to the auxiliary equipment system, is not performed. Therefore, the charging efficiency of the power generated by the solar panel 10 during parking can be improved.

[0059] As described above, an embodiment of the technology of the present disclosure has been described. However, the present disclosure can be regarded not only as a solar charging system, but also as a method performed by the solar charging system, a program of 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

[0060] The solar charging system of the present disclosure can be used in vehicles that charge a battery using the power generated by a solar panel.

Description of Signs

[0061] 1, 2 Solar charging system 10 Solar panel 20 Solar DDC 30 High-voltage DDC 40 Auxiliary DDC 50 Driving battery 60 Auxiliary battery 70 Parking service DDC 80 Control unit 90 Solar ECU 100 Operating equipment during parking

Claims

1. A solar charging system mounted on a vehicle, comprising: a solar panel; a drive battery used for driving the vehicle; an auxiliary battery that supplies power to in-vehicle devices operating during parking; a control unit that controls the power of the solar panel, the drive battery, and the auxiliary battery, wherein the control unit: during parking, controls not to simultaneously execute a charging process of supplying the generated power of the solar panel to the drive battery and a discharging process of supplying the power of the drive battery to an auxiliary system including the auxiliary battery and the in-vehicle devices; when the generated power of the solar panel is equal to or greater than the power consumption of the auxiliary system, controls to supply the generated power of the solar panel to the auxiliary battery, the auxiliary system, and the drive battery; when the generated power of the solar panel is less than the power consumption of the auxiliary system, controls to supply the generated power of the solar panel to the auxiliary system; a solar charging system.

2. When the generated power of the solar panel is equal to or greater than the power consumption of the auxiliary system, the control unit supplies the power of the solar panel that has not been consumed by the auxiliary system to the drive battery. The solar charging system according to Claim 1.

3. When the generated power of the solar panel is less than the power consumption of the auxiliary system, the control unit supplies the power insufficient for the generated power of the solar panel from the drive battery among the power consumption of the auxiliary system. The solar charging system according to Claim 1.

4. When the control unit supplies the generated power of the solar panel to the auxiliary system based on a predetermined target output voltage, if the output voltage of the auxiliary battery is less than a predetermined voltage, supplies the power of the drive battery to the auxiliary system in addition to the generated power of the solar panel; if the output voltage of the auxiliary battery is equal to or greater than the predetermined voltage, supplies the power of the solar panel that has not been consumed by the auxiliary system to the drive battery. The solar charging system according to Claim 1.

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