Control device for automotive solar panels

Abstract

This technology provides a mechanism to perform search control when the power generated by a solar cell drops sharply, and to vary the degree of power drop that determines whether or not to perform search control based on the vehicle's speed. [Solution] The control unit 24 of the vehicle solar cell control device 20 performs search control on the first power conversion unit 21 when it determines that the rate of decrease in the power generated by the first solar panel 11 per unit time exceeds a first threshold while performing follow control on the first power conversion unit 21, and performs search control on the second power conversion unit 22 when it determines that the rate of decrease in the power generated by the second solar panel 12 per unit time exceeds a second threshold while performing follow control on the second power conversion unit 22. The control unit 24 measures the time difference from when the power generated by the first solar panel 11 drops sharply until when the power generated by the second solar panel 12 drops sharply, and sets the first threshold and the second threshold based on the time difference.

Description

Technical Field

[0001] The present disclosure relates to a control device for an in-vehicle solar cell.

Background Art

[0002] Patent Document 1 discloses a photovoltaic power generation system including a maximum power point tracking module. The maximum power point tracking module performs maximum power point tracking. The maximum power point tracking module modifies the maximum power point tracking method, for example, in response to detecting that the solar cell is shaded. The modification is, for example, to perform a full sweep of the I-V curve. The maximum power point tracking module considers that a condition indicating shading of the solar cell is detected, for example, when the output power of the solar cell decreases while the voltage of the solar cell increases.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] During the running of a vehicle, the external environment is likely to change, and the change in the external environment is likely to affect the amount of power generated. Also, the higher the vehicle speed, the more likely the external environment is to change. However, in Patent Document 1, the vehicle speed is not considered when determining whether to modify the maximum power point tracking method. Therefore, there is room for improvement in this regard.

[0005] The present disclosure aims to provide a technology capable of performing search control when the power generation power of a solar cell drops sharply and varying the degree of the amount of decrease in the power generation power for determining whether to perform search control based on the vehicle speed.

Means for Solving the Problems

[0006] The control device for the first in-vehicle solar cell described herein is A first solar cell panel, a second solar cell panel positioned behind the first solar cell panel, and a battery electrically connected to both the first and second solar cell panels are installed in a vehicle. A first power conversion unit which adjusts the power input from the first solar panel and outputs it to the battery side, A second power conversion unit which adjusts the power input from the second solar panel and outputs it to the battery side, The system includes a control unit that performs follow-up control after performing search control on each of the first and second power conversion units, The aforementioned search control is a control that adjusts either the voltage or current on one of the input or output sides of the power conversion unit, changes the adjustment target in steps within a predetermined range, and detects the maximum power, which is the maximum power on the one side at each step within the predetermined range. The aforementioned tracking control is a control device for an on-board solar cell, which causes the power on one side of the power conversion unit to track the maximum power detected by the search control. The control unit performs the search control on the first power conversion unit if it determines that the decrease in the amount of power generated by the first solar panel per unit time exceeds a first threshold while performing the follow control on the first power conversion unit, and performs the search control on the second power conversion unit if it determines that the decrease in the amount of power generated by the second solar panel per unit time exceeds a second threshold while performing the follow control on the second power conversion unit. Furthermore, the control unit measures the time difference between the sharp decline in the power generated by the first solar panel and the sharp decline in the power generated by the second solar panel, and sets the first threshold and the second threshold based on the time difference.

[0007] The control device for the second in-vehicle solar cell in this disclosure is A solar panel including a first solar cell section and a second solar cell section positioned behind the first solar cell section, and a battery electrically connected to the first solar cell section and the second solar cell section, are installed in a vehicle. A power conversion unit that adjusts the power input from the solar panel and outputs it to the battery side, The system includes a control unit that performs search control on the power conversion unit and then performs follow control, The aforementioned search control is a control that adjusts either the voltage or current on one of the input or output sides of the power conversion unit, changes the adjustment target in steps within a predetermined range, and detects the maximum power, which is the maximum power on the one side at each step within the predetermined range. The tracking control is a control device for an on-board solar cell, which controls the power on one side of the power conversion unit to track the maximum power detected by the search control. The control unit performs the search control when it determines that the decrease in the amount of power generated by the solar panel per unit time exceeds a threshold during the execution of the tracking control. Furthermore, the control unit measures the time difference between the sharp decline in the power generated by the first solar cell and the sharp decline in the power generated by the second solar cell, and sets the threshold based on the time difference. [Effects of the Invention]

[0008] According to this disclosure, when the power generated by the solar cell drops sharply, search control can be performed, and the degree of decrease in power generation that determines whether or not to perform search control can be varied based on the vehicle's speed. [Brief explanation of the drawing]

[0009] [Figure 1] Figure 1 is a schematic diagram showing a vehicle equipped with a control device for an on-board solar cell according to the first embodiment. [Figure 2] Figure 2 is a flowchart of the first control performed by the control unit of the first embodiment. [Figure 3]FIG. 3 is a flowchart of the second control performed by the control unit of the first embodiment. [Figure 4] FIG. 4 is a flowchart of the third control performed by the control unit of the first embodiment. [Figure 5] FIG. 5 is a configuration diagram schematically showing a vehicle equipped with a control device for an in-vehicle solar cell according to the second embodiment. [Figure 6] FIG. 6 is a flowchart of the fifth control performed by the control unit of the second embodiment. [Figure 7] FIG. 7 is a flowchart of the sixth control performed by the control unit of the second embodiment.

MODE FOR CARRYING OUT THE INVENTION

[0010] [Description of Embodiments of the Present Disclosure] Hereinafter, embodiments of the present disclosure will be listed and exemplified.

[0011] 〔1〕A vehicle in which a first solar cell panel, a second solar cell panel disposed behind the first solar cell panel, and a battery electrically connected to each of the first solar cell panel and the second solar cell panel are installed, A first power conversion unit that adjusts the power input from the first solar cell panel and outputs it to the battery side, A second power conversion unit that adjusts the power input from the second solar cell panel and outputs it to the battery side, A control unit that performs follow-up control after performing search control on each of the first power conversion unit and the second power conversion unit, The search control is a control that targets either the voltage or current on one side of the input side and output side of the power conversion unit, changes the adjustment target stepwise within a predetermined width, and detects the maximum power, which is the maximum power among the powers on the one side at each step of the predetermined width. The follow-up control is a control device for an in-vehicle solar cell that causes the power on the one side of the power conversion unit to follow the maximum power detected by the search control. During the execution of the tracking control for the first power conversion unit, when it is determined that the decrease amount per unit time of the power generation power of the first solar panel exceeds a first threshold value, the search control is performed on the first power conversion unit. During the execution of the tracking control for the second power conversion unit, when it is determined that the decrease amount per unit time of the power generation power of the second solar panel exceeds a second threshold value, the search control is performed on the second power conversion unit. Furthermore, the control unit measures the time difference from when the power generation power of the first solar panel drops rapidly to when the power generation power of the second solar panel drops rapidly, and sets the first threshold value and the second threshold value based on the time difference. Vehicle-mounted solar cell control device.

[0012] During the execution of the tracking control for the first power conversion unit, when the control unit determines that the decrease amount per unit time of the power generation power of the first solar panel exceeds the first threshold value, it performs search control on the first power conversion unit. Therefore, when the power generation power of the first solar panel drops rapidly, search control can be performed on the first power conversion unit. Also, during the execution of the tracking control for the second power conversion unit, when the control unit determines that the decrease amount per unit time of the power generation power of the second solar panel exceeds the second threshold value, it performs search control on the second power conversion unit. Therefore, when the power generation power of the second solar panel drops rapidly, search control can be performed on the second power conversion unit. In addition, the control unit sets the first threshold value and the second threshold value based on the time difference from when the power generation power of the first solar panel drops rapidly to when the power generation power of the second solar panel drops rapidly. This time difference corresponds to the speed of the vehicle. That is, according to this configuration, it is possible to vary the degree of the decrease amount of the power generation power that determines whether to perform search control based on the speed of the vehicle.

[0013] 〔2〕The shorter the time difference, the smaller the control unit sets the first threshold value and the second threshold value. The vehicle-mounted solar cell control device according to 〔1〕.

[0014] With this configuration, the search control can be performed with a smaller reduction in speed, especially when the vehicle speed is high.

[0015] [3] The search control includes a first search control and a second search control, The first search control is a control that changes the adjustment target step by step within a predetermined range and detects the provisional maximum power, which is the maximum power among the powers on one side at each step within the predetermined range. The second search control is a control that steps the adjustment target in a second predetermined width smaller than the predetermined width, starting from a value smaller than the value of the adjustment target at the provisional maximum power in the first search control and larger than the lowest value of the adjustment target in each of the steps of the first search control, and detects the maximum power which is the maximum power of the power on one side at each of the steps of the second predetermined width. A control device for an in-vehicle solar cell as described in [1] or [2].

[0016] The control device for the above-mentioned on-board solar cell can first roughly detect the maximum power point using a first search control, and then more precisely detect the maximum power point using a second search control.

[0017] [4] A solar panel including a first solar cell section and a second solar cell section located behind the first solar cell section, and a battery electrically connected to the first solar cell section and the second solar cell section, are installed on a vehicle. A power conversion unit that adjusts the power input from the solar panel and outputs it to the battery side, The system includes a control unit that performs search control on the power conversion unit and then performs follow control, The aforementioned search control is a control that adjusts either the voltage or current on one of the input or output sides of the power conversion unit, changes the adjustment target in steps within a predetermined range, and detects the maximum power, which is the maximum power on the one side at each step within the predetermined range. The aforementioned tracking control is a control device for an on-board solar cell, which causes the power on one side of the power conversion unit to track the maximum power detected by the search control. The control unit performs the search control when it determines that the decrease in the amount of power generated by the solar panel per unit time exceeds a threshold during the execution of the tracking control. Furthermore, the control unit measures the time difference between the sharp decline in the power generated by the first solar cell and the sharp decline in the power generated by the second solar cell, and sets the threshold based on the time difference. Control device for in-vehicle solar panels.

[0018] The control unit performs search control when it determines that the rate of decrease in the solar panel's power generation per unit time exceeds a threshold during follow-up control. Therefore, search control can be performed when the solar panel's power generation drops sharply. The control unit also sets a threshold based on the time difference between the sharp drop in the power generation of the first solar panel and the sharp drop in the power generation of the second solar panel. This time difference corresponds to the vehicle's speed. In other words, with this configuration, the degree of decrease in power generation that determines whether or not to perform search control can be varied based on the vehicle's speed.

[0019] [Details of the embodiments of this disclosure] 1. First Embodiment 1-1. Configuration of Vehicle 1 Figure 1 discloses a vehicle 1 equipped with a control device 20 (hereinafter also referred to as the control device 20) for an on-board solar cell according to the first embodiment. The vehicle 1 is fitted with a first solar cell panel 11, a second solar cell panel 12, and a battery 13.

[0020] The second solar panel 12 is positioned behind the first solar panel 11. The front-rear direction is the front-rear direction of the vehicle 1. The first solar panel 11 and the second solar panel 12 are installed, for example, on the hood, roof, trunk, etc. of the vehicle 1. For example, the first solar panel 11 may be installed on the roof and the second solar panel 12 may be installed on the trunk. As another example, both the first solar panel 11 and the second solar panel 12 may be installed on the roof, with the second solar panel 12 positioned behind the first solar panel 11 on the roof.

[0021] The battery 13 is electrically connected to the first solar panel 11 and the second solar panel 12, respectively.

[0022] 1-2. Configuration of the control device 20 The control device 20 includes a first power conversion unit 21, a second power conversion unit 22, a voltage conversion unit 23, a control unit 24, a first input side conductive path 31, a second input side conductive path 32, an output side conductive path 33, and a battery side conductive path 34.

[0023] The first power conversion unit 21 is provided between the first solar panel 11 and the battery 13. The second power conversion unit 22 is provided between the second solar panel 12 and the battery 13. The voltage conversion unit 23 is provided between the first power conversion unit 21 and the second power conversion unit 22 and the battery 13.

[0024] The first input-side conductive path 31 is provided between the first solar cell panel 11 and the first power conversion unit 21. The first input-side conductive path 31 is electrically connected to the first solar cell panel 11 and electrically connected to one end of the first power conversion unit 21. The first input-side conductive path 31 supplies the power generated by the first solar cell panel 11 to the first power conversion unit 21.

[0025] The second input-side conductive path 32 is provided between the second solar cell panel 12 and the second power conversion unit 22. The second input-side conductive path 32 is electrically connected to the second solar cell panel 12 and electrically connected to one end of the second power conversion unit 22. The second input-side conductive path 32 supplies the power generated by the second solar cell panel 12 to the second power conversion unit 22.

[0026] The output conductive path 33 is provided between the first power conversion unit 21 and the second power conversion unit 22 and the voltage conversion unit 23. The output conductive path 33 is electrically connected to the other end of the first power conversion unit 21, to the other end of the second power conversion unit 22, and to one end of the voltage conversion unit 23. The output conductive path 33 supplies power from the first power conversion unit 21 to the voltage conversion unit 23 and supplies power from the second power conversion unit 22 to the voltage conversion unit 23.

[0027] The battery-side conductive path 34 is provided between the voltage conversion unit 23 and the battery 13. The battery-side conductive path 34 is electrically connected to the other end of the voltage conversion unit 23 and electrically connected to the battery 13. The battery-side conductive path 34 supplies power from the voltage conversion unit 23 to the battery 13.

[0028] The first power conversion unit 21 is a power conversion unit that adjusts the power input from the first solar panel 11 and outputs it to the battery 13. The first power conversion unit 21 is configured, for example, by an MPPT circuit. The MPPT circuit is a circuit that can operate in the MPPT (Maximum Power Point Tracking) manner under control from the control unit 24. The MPPT circuit is configured, for example, by a DC-DC converter. The first power conversion unit 21 boosts or lowers the voltage applied to the first input side conductive path 31 and outputs it to the output side conductive path 33.

[0029] The second power conversion unit 22 is a power conversion unit that adjusts the power input from the second solar cell panel 12 and outputs it to the battery 13. The second power conversion unit 22 is configured, for example, by an MPPT circuit. The second power conversion unit 22 boosts or lowers the voltage applied to the second input side conductive path 32 and outputs it to the output side conductive path 33.

[0030] The voltage conversion unit 23 is provided between the first power conversion unit 21 and the second power conversion unit 22 and the battery 13. The voltage conversion unit 23 boosts or lowers the voltage applied to the output side conductive path 33 and outputs it to the battery side conductive path 34. The voltage conversion unit 23 is configured, for example, by a DC-DC converter.

[0031] The power adjusted by the first power conversion unit 21 is converted to voltage by the voltage conversion unit 23 and supplied to the battery 13. The power adjusted by the second power conversion unit 22 is converted to voltage by the voltage conversion unit 23 and supplied to the battery 13.

[0032] The control unit 24 is comprised of, for example, a microcomputer. The control unit 24 includes, for example, a processor such as a CPU, and memory such as ROM or RAM. The control unit 24 controls the first power conversion unit 21, the second power conversion unit 22, and the voltage conversion unit 23.

[0033] 1-3. Operation of the control device 20 The control unit 24 performs search control for each of the first power conversion unit 21 and the second power conversion unit 22, and then performs follow control.

[0034] Search control is a control method that adjusts either the voltage or current on one of the input or output sides of the power conversion unit, changes the adjustment target in steps within a predetermined range, and detects the maximum power, which is the highest power on one side at each step within the predetermined range. Search control is performed individually for each of the first power conversion unit 21 and the second power conversion unit 22.

[0035] The search control includes a first search control and a second search control. The first search control is a control that changes the adjustment target stepwise within a predetermined range and detects the provisional maximum power, which is the maximum power on one side at each step within the predetermined range.

[0036] The second search control is a control that steps the adjustment target in a second predetermined width smaller than a predetermined width, starting from a value smaller than the value of the adjustment target at the provisional maximum power in the first search control and larger than the lowest adjustment target value in each stage of the first search control, and detects the maximum power, which is the maximum power on one side at each stage of the second predetermined width.

[0037] Tracking control is a control method that causes the power on one side of the power conversion unit to track the maximum power detected by the search control. Tracking control is performed individually for each of the first power conversion unit 21 and the second power conversion unit 22.

[0038] The control unit 24 performs search control on the first power conversion unit 21 when it determines that the decrease in the amount of power generated by the first solar panel 11 per unit time exceeds a first threshold while performing follow-up control on the first power conversion unit 21.

[0039] In this embodiment, the decrease is a percentage decrease, but it may also be a range of decrease. The control unit 24 periodically calculates the value of the power generated by the first solar cell panel 11 based on the output voltage and output current of the first solar cell panel 11. The decrease in power generated by the first solar cell panel 11 per unit time is, for example, the decrease relative to the moving average value of the power generated by the first solar cell panel 11. The decrease in power generated by the first solar cell panel 11 per unit time AD1 is calculated, for example, using the moving average value PA1 of the power generated by the first solar cell panel 11 and the most recent power generated by the first solar cell panel 11 PL1, by the following equation (1). AD1=(PA1-PL1) / PA1...Formula (1)

[0040] If the control unit 24 determines that the decrease in the amount of power generated by the second solar panel 12 per unit time exceeds the second threshold while performing tracking control for the second power conversion unit 22, it performs search control for the second power conversion unit 22.

[0041] The control unit 24 periodically calculates the value of the power generated by the second solar panel 12 based on the output voltage and output current of the second solar panel 12. The decrease in the power generated by the second solar panel 12 per unit time is, for example, the decrease relative to the moving average value of the power generated by the second solar panel 12. The decrease in the power generated by the second solar panel 12 per unit time AD2 is calculated, for example, using the moving average value PA2 of the power generated by the second solar panel 12 and the most recent power generated by the second solar panel 12 PL2, by the following equation (2). AD2=(PA2-PL2) / PA2...Formula (2)

[0042] The control unit 24 periodically acquires the value of the power generated by the second solar cell panel 12. The decrease in the power generated by the second solar cell panel 12 per unit time is, for example, the decrease in the most recent value of the power generated by the second solar cell panel 12 relative to the moving average value of the power generated by the second solar cell panel 12.

[0043] The control unit 24 measures the time difference between the sharp decline in the power generated by the first solar panel 11 and the sharp decline in the power generated by the second solar panel 12. Specifically, when the control unit 24 determines that the rate of decrease in the power generated by the first solar panel 11 per unit time exceeds a first determination value, it measures the time difference between the rate of decrease in the power generated by the first solar panel 11 per unit time exceeding the first determination value and the rate of decrease in the power generated by the second solar panel 12 per unit time exceeding a second determination value.

[0044] The first judgment value may be the same as the first threshold, greater than the first threshold, or less than the first threshold. The second judgment value may be the same as the second threshold, greater than the second threshold, or less than the second threshold.

[0045] The control unit 24 sets the first and second thresholds based on the time difference. The control unit 24 sets the first and second thresholds to smaller values ​​the shorter the time difference. In this embodiment, the control unit 24 calculates the speed of vehicle 1 based on the time difference. From the calculated speed, the control unit 24 determines whether vehicle 1 is stopped, moving at a low speed, or moving at a high speed. If vehicle 1 is moving, the control unit 24 sets the first and second thresholds to smaller values ​​than when vehicle 1 is stopped. If vehicle 1 is moving at a high speed, the control unit 24 sets the first and second thresholds to smaller values ​​than when vehicle 1 is moving at a low speed. For example, if vehicle 1 is stopped, the control unit 24 sets the first and second thresholds to 50%, if vehicle 1 is moving at a low speed, it sets the first and second thresholds to 40%, and if vehicle 1 is moving at a high speed, it sets the first and second thresholds to 30%.

[0046] The control unit 24 performs the first control, the second control, the third control, and the fourth control in parallel. The first control is the control of the first power conversion unit 21. The second control is the control of the second power conversion unit 22. The third control is the control of setting the first threshold and the second threshold. The fourth control is the control of the voltage conversion unit 23.

[0047] The control unit 24 performs the processing shown in Figure 2, for example, as the first control. The control unit 24 performs search control on the first power conversion unit 21 (step S11). After that, the control unit 24 starts tracking control on the first power conversion unit 21 (step S12). After starting tracking control, the control unit 24 obtains the value of the power generated by the first solar panel 11 and calculates the amount of decrease in the power generated by the first solar panel 11 per unit time (step S13). The control unit 24 determines whether the calculated decrease exceeds a first threshold (step S14). If the control unit 24 determines that the calculated decrease is less than or equal to the first threshold (No in step S14), it returns to step S13. In other words, the control unit 24 repeatedly determines whether the decrease exceeds the first threshold while performing tracking control on the first power conversion unit 21 until it determines that the decrease exceeds the first threshold. If the control unit 24 determines that the decrease amount exceeds the first threshold (Yes in step S14), it returns to step S11 and performs search control on the first power conversion unit 21.

[0048] The control unit 24 performs the processing shown in Figure 3, for example, as a second control. The control unit 24 performs search control on the second power conversion unit 22 (step S21). After that, the control unit 24 starts tracking control on the second power conversion unit 22 (step S22). After starting tracking control, the control unit 24 obtains the value of the power generated by the second solar cell panel 12 and calculates the amount of decrease in the power generated by the second solar cell panel 12 per unit time (step S23). The control unit 24 determines whether the calculated decrease exceeds the second threshold (step S24). If the control unit 24 determines that the calculated decrease is less than or equal to the second threshold (No in step S24), it returns to step S23. In other words, the control unit 24 repeatedly determines whether the decrease exceeds the second threshold while performing tracking control on the second power conversion unit 22 until it determines that the decrease exceeds the second threshold. If the control unit 24 determines that the decrease amount exceeds the second threshold (Yes in step S24), it returns to step S21 and performs search control on the second power conversion unit 22.

[0049] The control unit 24 performs the processing shown in Figure 4, for example, as a third control. The control unit 24 determines whether the power generated by the first solar panel 11 has dropped sharply (step S31). At this time, the control unit 24 may use the amount of drop calculated in the first control, or it may calculate the amount of drop separately. If the control unit 24 determines that the power generated by the first solar panel 11 has not dropped sharply (No in step S31), it returns to step S31. In other words, the control unit 24 repeatedly performs the processing in step S31 until it determines that the power generated by the first solar panel 11 has dropped sharply.

[0050] If the control unit 24 determines that the power generated by the first solar panel 11 has dropped sharply (Yes in step S31), it starts the timer (step S32). Then, the control unit 24 determines whether or not the power generated by the second solar panel 12 has dropped sharply (step S33). At this time, the control unit 24 may use the amount of drop calculated in the second control, or it may calculate the amount of drop separately. If the control unit 24 determines that the power generated by the second solar panel 12 has not dropped sharply (No in step S33), it determines whether or not the time has run out (step S34).

[0051] If the control unit 24 determines that time has not expired (No in step S34), it returns to step S33. In other words, the control unit 24 repeatedly performs the processes in steps S33 and S34 until it determines that the power generated by the second solar panel 12 has dropped sharply or that time has expired. If the control unit 24 determines that time has expired (Yes in step S34), it returns to step S31.

[0052] If the control unit 24 determines that the power generated by the second solar panel 12 has dropped sharply (Yes in step S33), it identifies the timer's operating time at that point as a time difference (step S35). Based on the identified time difference, the control unit 24 calculates the speed of the vehicle 1 (step S36). The control unit 24 sets the first threshold and the second threshold according to the calculated speed (step S37). The control unit 24 then returns to step S31.

[0053] In the fourth control, the control unit 24 causes the voltage conversion unit 23 to perform a boost or buck operation so that the output voltage of the voltage conversion unit 23 becomes the target voltage.

[0054] 1-4. Effects of the First Embodiment The control unit 24 performs search control on the first power conversion unit 21 when it determines that the rate of decrease in the power generated by the first solar panel 11 per unit time exceeds a first threshold during follow-up control of the first power conversion unit 21. Therefore, search control can be performed on the first power conversion unit 21 when the power generated by the first solar panel 11 drops sharply. In addition, the control unit 24 performs search control on the second power conversion unit 22 when it determines that the rate of decrease in the power generated by the second solar panel 12 per unit time exceeds a second threshold during follow-up control of the second power conversion unit 22. Therefore, search control can be performed on the second power conversion unit 22 when the power generated by the second solar panel 12 drops sharply. Furthermore, the control unit 24 sets the first and second thresholds based on the time difference between the sharp drop in the power generated by the first solar panel 11 and the sharp drop in the power generated by the second solar panel 12. This time difference corresponds to the speed of the vehicle 1. In other words, this configuration makes it possible to vary the degree of decrease in generated power that determines whether or not to perform search control based on the speed of vehicle 1.

[0055] The control unit 24 sets the first and second threshold values ​​to smaller values ​​as the time difference decreases. With this configuration, the search control can be performed with a smaller decrease amount when the speed of the vehicle 1 is high.

[0056] The control device 20 can perform a relatively rough detection of the maximum power point using a first search control, and then perform a more precise detection of the maximum power point using a second search control.

[0057] 2. Second Embodiment In the second embodiment, an example of measuring a time difference using two solar cell sections arranged front to back within a single solar cell panel will be described. In the second embodiment, the same reference numerals are used for components that are the same as in the first embodiment, and detailed explanations are omitted.

[0058] 2-1. Configuration of Vehicle 201 Figure 5 discloses a vehicle 201 equipped with a control device 220 for an on-board solar cell according to the second embodiment (hereinafter also referred to as the control device 220). The vehicle 201 is fitted with a solar panel 211 and a battery 13.

[0059] The solar panel 211 includes a first solar cell section 211A and a second solar cell section 211B positioned behind the first solar cell section 211A. The first solar cell section 211A and the second solar cell section 211B are connected in parallel to each other. Therefore, the solar panel 211 can output power generated by the second solar cell section 211B even when the first solar cell section 211A is unable to generate power, and can output power generated by the first solar cell section 211A even when the second solar cell section 211B is unable to generate power.

[0060] The battery 13 is electrically connected to the first solar cell unit 211A and the second solar cell unit 211B, respectively.

[0061] 2-2. Configuration of the control device 220 The control device 220 includes a power conversion unit 221, a voltage conversion unit 23, a control unit 224, an input-side conductive path 231, an output-side conductive path 233, and a battery-side conductive path 34.

[0062] The power conversion unit 221 is located between the solar panel 211 and the battery 13.

[0063] The input conductive path 231 is provided between the solar panel 211 and the power conversion unit 221. The input conductive path 231 is electrically connected to the solar panel 211 and electrically connected to one end of the power conversion unit 221. The input conductive path 231 supplies the power generated by the solar panel 211 to the power conversion unit 221.

[0064] The output conductive path 233 is provided between the power conversion unit 221 and the voltage conversion unit 23. The output conductive path 233 is electrically connected to the other end of the power conversion unit 221 and to one end of the voltage conversion unit 23. The output conductive path 233 supplies power from the power conversion unit 221 to the voltage conversion unit 23.

[0065] The power conversion unit 221 is a power conversion unit that adjusts the power input from the solar panel 211 and outputs it to the battery 13. The power conversion unit 221 is configured, for example, by an MPPT circuit. The power conversion unit 221 boosts or lowers the voltage applied to the input side conductive path 231 and outputs it to the output side conductive path 233.

[0066] The voltage conversion unit 23 is provided between the power conversion unit 221 and the battery 13. The voltage conversion unit 23 boosts or lowers the voltage applied to the output side conductive path 233 and outputs it to the battery side conductive path 34.

[0067] The power adjusted by the power conversion unit 221 is converted to voltage by the voltage conversion unit 23 and supplied to the battery 13.

[0068] The control unit 224 is comprised of, for example, a microcomputer. The control unit 224 includes, for example, a processor such as a CPU, and memory such as ROM or RAM. The control unit 224 controls the power conversion unit 221 and the voltage conversion unit 23.

[0069] 2-3. Operation of the control device 220 The control unit 224 performs search control on the power conversion unit 221, followed by tracking control. The search control and tracking control are as described in the first embodiment.

[0070] The control unit 224 performs search control when it determines that the decrease in the amount of power generated by the solar panel 211 per unit time exceeds a threshold during the execution of follow-up control.

[0071] In this embodiment, the decrease is a percentage decrease, but it may also be a range of decrease. The control unit 224 periodically calculates the value of the power generated by the solar cell panel 211 based on the output voltage and output current of the solar cell panel 211. The decrease in power generated by the solar cell panel 211 per unit time is, for example, the decrease relative to the moving average value of the power generated by the solar cell panel 211. The decrease in power generated by the solar cell panel 211 per unit time AD3 is calculated, for example, using the moving average value PA3 of the power generated by the solar cell panel 211 and the most recent power generated by the solar cell panel 211 PL3, by the following equation (3). AD3 = (PA3 - PL3) / PA3 ... Equation (3)

[0072] The control unit 224 measures the time difference between the sharp decline in the power generated by the first solar cell unit 211A and the sharp decline in the power generated by the second solar cell unit 211B. Based on the output voltage and output current of the first solar cell unit 211A, the control unit 224 calculates the power generated by the second solar cell unit 211B based on the output voltage and output current of the second solar cell unit 211B.

[0073] When the control unit 224 determines that the rate of decrease in the power generated by the first solar cell unit 211A per unit time exceeds a first determination value, it measures the time difference from when the rate of decrease in the power generated by the first solar cell unit 211A per unit time exceeds the first determination value until when it determines that the rate of decrease in the power generated by the second solar cell unit 211B per unit time exceeds a second determination value.

[0074] The control unit 224 periodically calculates the value of the power generated by the first solar cell unit 211A based on the output voltage and output current of the first solar cell unit 211A. The decrease in the power generated by the first solar cell unit 211A per unit time is, for example, the decrease relative to the moving average value of the power generated by the first solar cell unit 211A. The decrease in the power generated by the first solar cell unit 211A per unit time AD4 is calculated, for example, using the moving average value PA4 of the power generated by the first solar cell unit 211A and the most recent power generated by the first solar cell unit 211A PL4, by the following equation (4). AD4=(PA4-PL4) / PA4...Formula (4)

[0075] The control unit 224 periodically calculates the value of the power generated by the second solar cell unit 211B based on the output voltage and output current of the second solar cell unit 211B. The decrease in the power generated by the second solar cell unit 211B per unit time is, for example, the decrease relative to the moving average value of the power generated by the second solar cell unit 211B. The decrease in the power generated by the second solar cell unit 211B per unit time AD5 is calculated, for example, using the moving average value PA5 of the power generated by the second solar cell unit 211B and the most recent power generated by the second solar cell unit 211B PL5, by the following equation (5). AD5=(PA5-PL5) / PA5...Formula (53)

[0076] The control unit 224 sets a threshold value based on the time difference. The control unit 224 sets a smaller threshold value the shorter the time difference. The specific setting method is the same as in the first embodiment.

[0077] The control unit 224 performs the fifth control in place of the first and second controls of the first embodiment, and performs the sixth control in place of the third control of the first embodiment. The control unit 224 performs the fifth control, the sixth control, and the fourth control in parallel.

[0078] The control unit 224 performs the processing shown in Figure 6, for example, as the fifth control. The control unit 224 performs search control (step S51). After that, the control unit 224 starts tracking control (step S52). After starting tracking control, the control unit 224 obtains the value of the power generated by the solar panel 211 and calculates the amount of decrease in the power generated by the solar panel 211 per unit time (step S53). The control unit 224 determines whether the calculated decrease exceeds a threshold (step S54). If the control unit 224 determines that the calculated decrease is less than or equal to the threshold (No in step S54), it returns to step S53. In other words, the control unit 224 performs tracking control and repeatedly determines whether the decrease exceeds the threshold until it determines that the decrease has exceeded the threshold. If the control unit 224 determines that the decrease has exceeded the threshold (Yes in step S54), it returns to step S51 and performs search control.

[0079] As a sixth control, the control unit 224 performs the processing shown in Figure 7, for example. The control unit 224 calculates the decrease in the power generated by the first solar cell unit 211A per unit time and determines whether the power generated by the first solar cell unit 211A has decreased sharply (step S61). If the control unit 224 determines that the power generated by the first solar cell unit 211A has not decreased sharply (No in step S61), it returns to step S61. In other words, the control unit 224 repeatedly performs the processing in step S61 until it determines that the power generated by the first solar cell unit 211A has decreased sharply.

[0080] If the control unit 224 determines that the power generated by the first solar cell unit 211A has dropped sharply (Yes in step S61), it starts the timer (step S62). The control unit 224 then calculates the amount of decrease per unit time of the power generated by the second solar cell unit 211B and determines whether or not the power generated by the second solar cell unit 211B has dropped sharply (step S63). If the control unit 224 determines that the power generated by the second solar cell unit 211B has not dropped sharply (No in step S63), it determines whether or not the time has run out (step S64).

[0081] If the control unit 224 determines that time has not expired (No in step S64), it returns to step S63. In other words, the control unit 224 repeatedly performs the processes in steps S63 and S64 until it determines that the power generated by the second solar cell unit 211B has dropped sharply or that time has expired. If the control unit 224 determines that time has expired (Yes in step S64), it returns to step S61.

[0082] If the control unit 224 determines that the power generated by the second solar cell unit 211B has dropped sharply (Yes in step S63), it identifies the timer's operating time at that point as a time difference (step S65). Based on the identified time difference, the control unit 224 calculates the speed of the vehicle 201 (step S66). The control unit 224 sets a threshold according to the calculated speed (step S67). The control unit 224 then returns to step S61.

[0083] 2-4. Effects of the Second Embodiment The control unit 224 performs search control when it determines that the rate of decrease in the power generated by the solar panel 211 per unit time exceeds a threshold during the execution of follow control. Therefore, search control can be performed when the power generated by the solar panel 211 drops sharply. The control unit 224 also sets a threshold based on the time difference between the sharp drop in the power generated by the first solar cell unit 211A and the sharp drop in the power generated by the second solar cell unit 211B. This time difference corresponds to the speed of the vehicle 201. In other words, with this configuration, the degree of decrease in power generated that determines whether or not to perform search control can be varied based on the speed of the vehicle 201.

[0084] The control unit 224 sets the threshold value to a smaller value the shorter the time difference. With this configuration, the search control can be performed with a smaller decrease amount when the vehicle 201 is moving at a higher speed.

[0085] The control device 220 can perform a relatively rough detection of the maximum power point using a first search control, and then perform a more precise detection of the maximum power point using a second search control.

[0086] <Other Embodiments> The present invention is not limited to the embodiments described above and in the drawings, and the following embodiments, for example, are also included in the technical scope of the present invention. Furthermore, the various features of the embodiments described above and those described later may be combined in any way as long as they are not contradictory.

[0087] In the first embodiment, the configuration may include three or more solar panels. In the second embodiment, the configuration may include three or more solar cell sections on a single solar panel.

[0088] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope set forth in the claims or equivalents thereof. [Explanation of symbols]

[0089] 1…Vehicle 11…First solar panel 12…Second solar panel 13…Battery 20...Control device 21...First power conversion unit 22...Second power conversion unit 23...Voltage conversion section 24... Control Unit 31...First input side conductive path 32...Second input side conductive path 33…Output side conductive path 34...Battery-side conductive path 201... Vehicle 211… Solar panels 211A…1st solar cell section 211B…Second solar cell section 220...Control device 221...Power conversion unit 224... Control Unit 231...Input side conductive path 233…Output side conductive path

Claims

1. A first solar cell panel, a second solar cell panel positioned behind the first solar cell panel, and a battery electrically connected to both the first and second solar cell panels are installed in a vehicle. A first power conversion unit which adjusts the power input from the first solar panel and outputs it to the battery side, A second power conversion unit which adjusts the power input from the second solar panel and outputs it to the battery side, The system includes a control unit that performs follow-up control after performing search control on each of the first power conversion unit and the second power conversion unit, The aforementioned search control is a control that adjusts either the voltage or current on one of the input or output sides of the power conversion unit, changes the adjustment target in steps within a predetermined range, and detects the maximum power, which is the maximum power on the one side at each step within the predetermined range. The tracking control is a control device for an on-board solar cell, which controls the power on one side of the power conversion unit to track the maximum power detected by the search control. The control unit performs the search control on the first power conversion unit if it determines that the decrease in the amount of power generated by the first solar panel per unit time exceeds a first threshold while performing the follow control on the first power conversion unit, and performs the search control on the second power conversion unit if it determines that the decrease in the amount of power generated by the second solar panel per unit time exceeds a second threshold while performing the follow control on the second power conversion unit. Furthermore, the control unit measures the time difference between the sharp decline in the power generated by the first solar panel and the sharp decline in the power generated by the second solar panel, and sets the first threshold and the second threshold based on the time difference. Control device for automotive solar panels.

2. The control unit sets the first threshold and the second threshold to smaller values ​​as the time difference decreases. A control device for an in-vehicle solar cell according to claim 1.

3. The search control includes a first search control and a second search control. The first search control is a control that changes the adjustment target step by step within a predetermined range and detects the provisional maximum power, which is the maximum power among the powers on one side at each step within the predetermined range. The second search control is a control that steps the adjustment target in a second predetermined width smaller than the predetermined width, starting from a value smaller than the value of the adjustment target at the provisional maximum power in the first search control and larger than the lowest value of the adjustment target in each of the steps of the first search control, and detects the maximum power which is the maximum power of the power on one side at each of the steps of the second predetermined width. A control device for an in-vehicle solar cell according to claim 1 or claim 2.

4. A solar panel including a first solar cell section and a second solar cell section positioned behind the first solar cell section, and a battery electrically connected to the first solar cell section and the second solar cell section, are installed in a vehicle. A power conversion unit that adjusts the power input from the solar panel and outputs it to the battery side, The system includes a control unit that performs search control on the power conversion unit and then performs follow control, The aforementioned search control is a control that adjusts either the voltage or current on one of the input or output sides of the power conversion unit, changes the adjustment target in steps within a predetermined range, and detects the maximum power, which is the maximum power on the one side at each step within the predetermined range. The tracking control is a control device for an on-board solar cell, which controls the power on one side of the power conversion unit to track the maximum power detected by the search control. The control unit performs the search control when it determines that the decrease in the amount of power generated by the solar panel per unit time exceeds a threshold during the execution of the tracking control. Furthermore, the control unit measures the time difference between the sharp decline in the power generated by the first solar cell and the sharp decline in the power generated by the second solar cell, and sets the threshold based on the time difference. Control device for automotive solar panels.

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