JP7694499B2 - Solar charging device - Google Patents

Description

This disclosure relates to a solar charging device that controls the supply of electricity generated by a solar panel mounted on a vehicle.

Patent document 1 discloses a solar charging control device that controls a solar DC-DC converter, a high-voltage DC-DC converter, and an auxiliary DC-DC converter that are provided between a solar panel and a high-voltage battery and an auxiliary battery, and can suitably supply the power generated by the solar panel to the high-voltage battery and the auxiliary battery.

JP 2021-086302 A

In the configuration described in Patent Document 1, when transferring power between a high-voltage battery and an auxiliary battery, depending on the operating state of the high-voltage DCDC converter and the auxiliary DCDC converter, it becomes necessary to stop the solar DCDC converter. In such a case, even if the solar panel is in a state where it can generate power, it cannot generate power, resulting in a loss of the opportunity to generate power.

This disclosure was made in consideration of the above-mentioned problems, and aims to provide a solar charging device that can reduce the loss of power generation opportunities using solar panels.

In order to solve the above problems, one aspect of the disclosed technology is a solar charging device mounted on a vehicle, comprising a solar panel, a drive battery, an auxiliary battery, a first DC-DC converter provided between the solar panel and the auxiliary battery, a second DC-DC converter provided between the drive battery and the auxiliary battery, and a control unit that controls the first DC-DC converter and the second DC-DC converter, and the control unit supplies the power generated by the solar panel to the auxiliary battery via the first DC-DC converter when the power generated by the solar panel is greater than the power consumption of an auxiliary load connected to the auxiliary battery, and supplies the power generated by the solar panel to the auxiliary battery via the first DC-DC converter and supplies the power of the drive battery to the auxiliary battery via the second DC-DC converter when the power generated by the solar panel is less than the power consumption of the auxiliary load.

The solar charging device disclosed herein can reduce the loss of power generation opportunities through solar panels.

FIG. 1 is a block diagram of a solar charging device according to an embodiment of the present disclosure. A flowchart of the charging control process executed by the solar charging device A flowchart of the charging control process executed by the solar charging device FIG. 1 is a diagram explaining the boost operation of a battery bidirectional DC-DC converter. FIG. 1 is a diagram explaining the step-down operation of a battery bidirectional DC-DC converter.

The solar charging device according to the present disclosure supplies power generated by the solar panel based on the state of power transfer between the drive battery and the auxiliary battery in the vehicle system. This ensures consistency between the vehicle's power control operation and the solar power generation operation, and reduces the loss of opportunities for power generation by the solar panel.
Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

<Embodiment>
[composition]
FIG. 1 is a block diagram showing a schematic configuration of a solar charging device 1 according to an embodiment of the present disclosure. The solar charging device 1 illustrated in FIG. 1 includes a solar module 10, an auxiliary battery 20, a driving battery 30, a battery bidirectional DC-DC converter (battery bidirectional DDC) 40, and a control unit 50. In FIG. 1, a connection line through which electric power is transmitted is shown by a solid line, and a connection line through which control signals other than electric power are transmitted is shown by a dashed line. This solar charging device 1 is mounted on a vehicle such as a hybrid electric vehicle (HEV), a plug-in hybrid electric vehicle (PHEV), and an electric vehicle (BEV).

The solar module 10 is a power generation device that generates electricity when exposed to sunlight, and outputs the generated electricity to an auxiliary battery 20 and an auxiliary load 100 that are connected to the solar module 10. The solar module 10 includes a solar panel 11, a solar DC-DC converter (solar DDC) 12, and a solar control unit 13.

The solar panel 11 is a device that can generate power from sunlight according to the amount of irradiation, and is typically a collection of solar cells. The power generated by the solar panel 11 is output to the solar DC-DC converter 12. This solar panel 11 is installed, for example, on the roof of a vehicle.

The solar DC-DC converter 12 is a power converter (first DC-DC converter) that inputs the power generated by the solar panel 11, converts the input power to a predetermined voltage, and outputs it. This solar DC-DC converter 12 controls the conversion and output of the generated power according to instructions from the solar control unit 13. The output of the solar DC-DC converter 12 is supplied to the auxiliary battery 20 and the auxiliary load 100, and to the drive battery 30 via the battery bidirectional DC-DC converter 40.

The solar control unit 13 is an electronic control device (first control unit) that is composed of a processor such as a CPU and controls the operation of the solar DC-DC converter 12. This solar control unit 13 can acquire information on the power generated by the solar panel 11. The power generated by the solar panel 11 can be calculated, for example, from measurements of a current sensor and a voltage sensor (not shown) provided in the solar panel 11 and the solar control unit 13. The solar control unit 13 can also acquire information on the power consumed by the auxiliary load 100 and the auxiliary battery 20. The power consumption by the auxiliary load 100 and the auxiliary battery 20 can be calculated, for example, based on the output voltage and outflow current of the solar DC-DC converter 12.

The solar control unit 13 also communicates (through CAN communication, LIN communication, etc.) with a control unit 50 that is provided independently of the solar module 10 and controls the vehicle's power supply, and controls the charging and discharging of power in the vehicle in cooperation with the control unit 50. The solar control unit 13, together with the control unit 50, constitutes a control unit that optimally controls the power generated by the solar power generation and the power stored in each battery.

The auxiliary battery 20 is a secondary battery configured to be chargeable and dischargeable, such as a lithium-ion battery or a lead-acid battery. This auxiliary battery 20 is connected to the solar DC-DC converter 12 of the solar module 10 so that it can be charged with power generated by the solar panel 11. The auxiliary battery 20 is also connected to the battery bidirectional DC-DC converter 40 so that it can be charged with power stored in the drive battery 30. The auxiliary battery 20 can also supply the auxiliary load 100 with the power required for the operation of the auxiliary load 100.

The driving battery 30 is a secondary battery configured to be chargeable and dischargeable, such as a lithium-ion battery or a nickel-metal hydride battery. The driving battery 30 is connected to the solar DC-DC converter 12 of the solar module 10 via the battery bidirectional DC-DC converter 40 so that it can be charged by the power generated by the solar panel 11. The driving battery 30 is also connected to a main device (not shown) for driving the vehicle, and can supply the power required for the operation of the main device. Examples of the main device include a starter motor and an electric motor for driving. The driving battery 30 is a high-voltage battery with a higher rated voltage than the auxiliary battery 20.

The battery bidirectional DC-DC converter 40 is a power converter (second DC-DC converter) that can convert input power into power of a predetermined voltage and output it based on the instruction of the control unit 50. One end (called the primary side) of this battery bidirectional DC-DC converter 40 is connected to the solar module 10, the auxiliary battery 20, and the auxiliary load 100, and the other end (called the secondary side) is connected to the driving battery 30. The battery bidirectional DC-DC converter 40 can supply the output power of the solar module 10 connected to the primary side to the driving battery 30 connected to the secondary side (boost operation), and can also supply the power of the driving battery 30 connected to the secondary side to the auxiliary battery 20 and the auxiliary load 100 connected to the primary side (step-down operation). During this power supply, the battery bidirectional DC-DC converter 40 steps up the output voltage of the solar module 10, which is the input voltage of the primary side, to the output voltage of the secondary side (step-up operation), and steps down the voltage of the driving battery 30, which is the input voltage of the secondary side, to the output voltage of the primary side (step-down operation).

The control unit 50 is an electronic control device (second control unit) that includes a processor, memory, and an input/output interface, and controls the operation of the battery bidirectional DC-DC converter 40. For example, an HV-ECU that controls the hybrid driving of the vehicle can be used as this control unit 50. The control unit 50 communicates (CAN communication, LIN communication, etc.) with the solar control unit 13 of the solar module 10, which together constitute a control unit, and controls the charging and discharging of power in the vehicle in cooperation with it. The control performed by the solar control unit 13 and the control unit 50 will be described later.

The auxiliary loads 100 are various auxiliary devices mounted on the vehicle. The auxiliary loads 100 operate by receiving power generated by the solar panel 11 of the solar module 10 and power stored in the auxiliary battery 20. 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 driving assistance.

[control]
Next, the control performed in the solar charging device 1 according to this embodiment will be described with further reference to Figures 2A, 2B, 3, and 4. Figures 2A and 2B are flow charts for explaining the processing procedure of the charging control executed by the solar control unit 13 and the control unit 50 constituting the control unit. The processing in Figure 2A and the processing in Figure 2B are connected by connectors X and Y, respectively. Figure 3 is a diagram showing the flow of power when the battery bidirectional DC-DC converter 40 is performing a step-up operation. Figure 4 is a diagram showing the flow of power when the battery bidirectional DC-DC converter 40 is performing a step-down operation.

The charging control illustrated in Figures 2A and 2B is started, for example, when the solar control unit 13, which has stopped some or all of its functions (sleep), becomes capable of generating electricity through exposure to sunlight and starts up (wakes up) the stopped functions.

(Step S201)
The solar control unit 13 calculates the generated power Wgen, which is the power generated by the solar panel 11. When the generated power Wgen of the solar panel 11 is calculated by the solar control unit 13, the process proceeds to step S202.

(Step S202)
The solar control unit 13 judges whether the power generation Wgen of the solar panel 11 exceeds a predetermined first threshold value Wsol. This judgment is made to judge whether the solar panel 11 generates enough power to perform efficient charging control. For example, if the power generation Wgen of the solar panel 11 is less than the power required for the charging operation of the solar module 10, power is taken out from the auxiliary battery 20, and the battery power consumed is greater than the power that can be obtained by solar power generation, making charging control meaningless. Therefore, the first threshold value Wsol can be set to a value equal to or greater than the power that allows charging control without taking out power from the auxiliary battery 20. If the solar control unit 13 judges that the power generation Wgen of the solar panel 11 exceeds the first threshold value Wsol (Wgen>Wsol) (step S202, Yes), the process proceeds to step S204. On the other hand, if the solar control unit 13 determines that the power generation Wgen of the solar panel 11 does not exceed the first threshold value Wsol (Wgen≦Wsol) (step S202, No), the process proceeds to step S203.

(Step S203)
Since the solar control unit 13 cannot perform efficient charging control using power generated by the solar panel, it stops the operation of some or all of the predetermined functions and puts the solar control unit 13 into sleep mode, thereby terminating the main charging control.

(Step S204)
The solar control unit 13 requests the control unit 50 to start power generation by the solar panel 11, i.e., to start outputting the generated power Wgen to the auxiliary battery 20, etc. When the solar control unit 13 requests the solar panel 11 to start power generation, the process proceeds to step S205.

(Step S205)
The control unit 50, upon receiving a request from the solar control unit 13 to start power generation by the solar panel 11, judges whether or not power generation by the solar panel 11 (output of generated power Wgen) is possible. This judgment is made based on, for example, the state of the drive battery 30 and the operating state of the vehicle. If the control unit 50 judges that solar power generation is possible (step S205, Yes), the process proceeds to step S206. On the other hand, if the control unit 50 judges that solar power generation is not possible (step S205, No), the process proceeds to step S207.

(Step S206)
The control unit 50 notifies the solar control unit 13 that solar power generation is permitted. When the control unit 50 notifies the solar control unit 13 that solar power generation is permitted, the process proceeds to step S208.

(Step S207)
The control unit 50 notifies the solar control unit 13 that solar power generation is not permitted. When the control unit 50 notifies that solar power generation is not permitted, the process proceeds to step S203.

(Step S208)
The solar control unit 13 starts power generation by the solar panel 11 based on the permission notification for solar power generation received from the control unit 50. This power generation can use well-known maximum power point tracking (MPPT) control or the like. When solar power generation is started by the solar control unit 13, the process proceeds to step S209.

(Step S209)
The solar control unit 13 controls the solar DC-DC converter 12 so that the output voltage of the solar DC-DC converter 12 is converted to a predetermined voltage. The predetermined voltage is typically the rated voltage (e.g., 12 V or 48 V) of the auxiliary battery 20. When the output voltage of the solar DC-DC converter 12 is controlled by the solar control unit 13, the process proceeds to step S210.

(Step S210)
The control unit 50 controls the battery bidirectional DCDC converter 40 to control the voltage Vaux of the auxiliary battery 20 to a predetermined constant voltage Vtgt. This voltage Vtgt is a target value for voltage control, and is set arbitrarily based on the performance of the auxiliary battery 20 and the specifications of the vehicle in which it is mounted. When the control unit 50 controls the voltage Vaux of the auxiliary battery 20 to the voltage Vtgt, the process proceeds to step S211.

(Step S211)
The control unit 50 judges whether the voltage Vaux of the auxiliary battery 20 is equal to or higher than a predetermined second threshold value Vhigh. This judgment is made to judge whether the generated power Wgen of the solar panel 11 can be effectively utilized only by supplying power to the auxiliary battery 20 and the auxiliary load 100. For example, when the state of charge (SOC) of the auxiliary battery 20 is close to full charge, a state occurs in which a part (or all) of the generated power Wgen of the solar panel 11 must be discarded only by supplying power to the auxiliary battery 20 and the auxiliary load 100, and the generated power may not be effectively utilized. Therefore, the second threshold value Vhigh can be set to a voltage value when the auxiliary battery 20 is close to full charge (for example, the state of charge is 85 to 95%). When the control unit 50 determines that the voltage Vaux of the auxiliary battery 20 is equal to or higher than the second threshold Vhigh (Vaux≧Vhigh) (step S211, Yes), the process proceeds to step S212. On the other hand, when the control unit 50 determines that the voltage Vaux of the auxiliary battery 20 is lower than the second threshold Vhigh (Vaux<Vhigh) (step S211, No), the process proceeds to step S213.

(Step S212)
The control unit 50 controls the battery bidirectional DC-DC converter 40 in a boost operation. This boost control allows the surplus power of the generated power Wgen of the solar panel 11 that is not consumed by the auxiliary battery 20 and the auxiliary load 100 to be output to the driving battery 30 to charge the driving battery 30, as shown by the arrow in Fig. 3. When the battery bidirectional DC-DC converter 40 is controlled in a boost operation by the control unit 50, the process proceeds to step S201.

(Step S213)
The control unit 50 controls the battery bidirectional DC-DC converter 40 in a step-down operation. This step-down control allows the drive battery 30 to provide the power required for consumption by the auxiliary battery 20 and the auxiliary load 100 that is insufficient with only the generated power Wgen of the solar panel 11, as shown by the arrows in Fig. 4. This makes it possible to suppress a decrease in power of the auxiliary battery 20. When the control unit 50 controls the battery bidirectional DC-DC converter 40 in a step-down operation, the process proceeds to step S201.

In the above embodiment, the case has been described in which the DCDC converter inserted between the auxiliary battery 20 and the driving battery 30 is a bidirectional battery DCDC converter 40 capable of both stepping up and stepping down. However, if power transfer from the auxiliary battery 20 to the driving battery 30 is not required, a DCDC converter dedicated to stepping down that can only transfer power from the driving battery 30 to the auxiliary battery 20 may be inserted between the auxiliary battery 20 and the driving battery 30.

In addition, in the above embodiment, the solar control unit 13 is provided within the solar module 10, but it can also be provided separately from the solar module 10 or can be included in the control unit 50.

<Action and Effects>
As described above, according to the solar charging device 1 according to an embodiment of the present disclosure, the battery bidirectional DC-DC converter 40, which is a standard component of the vehicle, is used in the solar power generation system. This ensures consistency between the power control operation of the vehicle and the solar power generation operation, and reduces the loss of power generation opportunities by the solar panel 11.

In addition, in the solar charging device 1 according to this embodiment, power is not supplied directly from the solar module 10 to the drive battery 30, but is instead supplied via the battery bidirectional DC-DC converter 40, eliminating the need for a dedicated solar boost DC-DC converter that was previously required. This contributes to reducing the cost of the solar power generation system, reducing the number of parts, and improving the ease of mounting parts.

In addition, in the solar charging device 1 according to this embodiment, the solar panel 11, the solar DC-DC converter 12, and the solar control unit 13 are integrated into the solar module 10. This makes it easy to introduce a solar power generation system into a vehicle and increase the amount of power generation.

One embodiment of the disclosed technology has been described above, but the present disclosure can be understood as not only a solar charging device, but also a charging control method, a control program for that method, a computer-readable non-transitory storage medium storing that control program, a vehicle equipped with a solar charging device, and the like.

The solar charging device disclosed herein can be used in vehicles equipped with solar panels.

Reference Signs List 1: Solar charging device 10: Solar module 11: Solar panel 12: Solar DC-DC converter 13: Solar control unit 20: Auxiliary battery 30: Driving battery 40: Battery bidirectional DC-DC converter 50: Control unit 100: Auxiliary load

Claims (4)

A solar charging device mounted on a vehicle,
Solar panels and
A drive battery;
An auxiliary battery;
a first DC-DC converter provided between the solar panel and the auxiliary battery;
a second DC-DC converter provided between the driving battery and the auxiliary battery;
A control unit that controls the first DC-DC converter and the second DC-DC converter,
The control unit
When the power generated by the solar panel is greater than the power consumption of an auxiliary load connected to the auxiliary battery, the power generated by the solar panel is supplied to the auxiliary battery via the first DC-DC converter;
When the power generated by the solar panel is smaller than the power consumption of the auxiliary load, the power generated by the solar panel is supplied to the auxiliary battery via the first DC-DC converter, and the power of the drive battery is supplied to the auxiliary battery via the second DC-DC converter.
Solar charging device. when the power generated by the solar panel is greater than the power consumed by the auxiliary load, the control unit supplies the power generated by the solar panel to the auxiliary battery via the first DCDC converter, and supplies the power generated by the solar panel to the drive battery via the first DCDC converter and the second DCDC converter.
The solar charging device according to claim 1. The control unit includes a first control unit that controls the first DC-DC converter and a second control unit that controls the second DC-DC converter,
The first DC-DC converter and the first control unit are modularized together with the solar panel.
The solar charging device according to claim 2. the first control unit receives permission to generate power from the second control unit and supplies the generated power of the solar panel to the auxiliary battery via the first DC-DC converter;
The solar charging device according to claim 3.

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