Scan Control Device

Abstract

To provide a scan control device which can suppress a reduction in power generation efficiency of an entire system even when there is a solar module which cannot accurately track the maximum power point of a solar panel.SOLUTION: A scan control device controls scan processing of scanning the output voltage of each solar panel executed by each power generation control unit to search for a maximum power point in a system in which a plurality of solar modules are connected, each including a solar panel, a sensor for acquiring the power generation state of the solar panel, and a power generation control unit for controlling the power generation of the solar panel on the basis of the power generation state. The scan control device comprises: a determination unit for determining whether or not the power generation state of each solar panel satisfies a prescribed condition; and an indication unit which, when there is a solar module whose power generation state of the soler panel does not satisfy a prescribed condition and which is a control object, indicates power generation control of the solar panel based on the result of the scan processing in a specific solar module to the power generation control unit of the solar module being the control object.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to a scan control device provided in a solar charging system mounted on a vehicle or the like. [Background technology]

[0002] Patent Document 1 discloses an on-board solar charging system equipped with multiple solar panels. In the solar charging system described in Patent Document 1, each solar control device provided for each solar panel executes maximum power point tracking (MPPT) control for the solar panel that is the control target of that device. In this MPPT control, in order to search for the maximum power point with high accuracy when the output voltage of the solar panel changes due to environmental changes such as changes in solar radiation conditions, a scanning process is performed to scan the output voltage of the solar panel and find the optimal point on the PV curve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2020-141545 Summary of the Invention [Problem to be solved by the invention]

[0004] In the solar charging system described in Patent Document 1, multiple solar control devices each independently perform MPPT control of the solar panels they control, but no cooperative processing is performed between the multiple solar control devices. As a result, if there is a solar module that cannot accurately track the maximum power point of the solar panel due to a sensor failure or control abnormality, the scanning accuracy of that solar panel will decrease, the scanning frequency will increase, and the scanning time will increase, resulting in a decrease in the power generation efficiency of the entire solar charging system.

[0005] The present disclosure has been made in consideration of the above-mentioned problems, and aims to provide a scanning control device that can suppress a decrease in power generation efficiency of the entire solar charging system even when there is a solar module that cannot accurately track the maximum power point of the solar panel. [Means for solving the problem]

[0006] In order to solve the above problems, one aspect of the disclosed technology is a scan control device that controls a scan process executed by each power generation control unit to scan the output voltage of each solar panel to search for a maximum power point in a system in which multiple solar modules are connected, each solar module comprising a solar panel, a sensor for acquiring the power generation state of the solar panel, and a power generation control unit for controlling the power generation of the solar panel based on the power generation state of the solar panel, and the scan control device includes: a judgment unit that judges whether the power generation state of each solar panel satisfies predetermined conditions; and, if there is a solar module to be controlled for which the judgment unit has judged that the power generation state of the solar panel does not satisfy the predetermined conditions, an instruction unit that instructs the power generation control unit of the solar module to be controlled to control the power generation of the solar panel based on the results of the scan process on a specific solar module different from the solar module to be controlled. [Effects of the Invention]

[0007] According to the scan control device of the present disclosure, even if there is a solar module that cannot accurately track the maximum power point of the solar panel, it is possible to suppress a decrease in the power generation efficiency of the entire solar charging system. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a block diagram showing an example of the configuration of a solar charging system including a scan control device according to an embodiment of the present invention. [Figure 2A] A diagram showing an example of multiple solar panels mounted on a vehicle in a multi-system structure [Figure 2B]A diagram showing an example of multiple solar panels mounted on a vehicle in a multi-junction structure. [Figure 3] Flowchart of scan processing control performed by the scan control device DETAILED DESCRIPTION OF THE INVENTION

[0009] When there is a solar module among multiple solar modules that is not performing well in MPPT control, the scanning control device of the present disclosure applies the results of scanning the other solar modules that have no problems in MPPT control to the power generation control of the solar module that is not performing well in MPPT control. This control prevents a decrease in the power generation efficiency of the entire solar charging system. Hereinafter, an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0010] <Embodiment> [composition] Fig. 1 is a block diagram showing a schematic configuration of a solar charging system 1 including a scan control device 50 according to an embodiment of the present disclosure. The solar charging system 1 illustrated in Fig. 1 includes a first solar module 10, a second solar module 20, a battery 30, a load device 40, and a scan control device 50. In Fig. 1, thick solid lines indicate connection lines through which power is transmitted, and dotted lines indicate connection lines through which control signals, detection values, and other signals other than power are transmitted and received. This solar charging system 1 can be installed in vehicles such as hybrid electric vehicles (HEVs), plug-in hybrid electric vehicles (PHEVs), and battery electric vehicles (BEVs).

[0011] The first solar module 10 and the second solar module 20 are power generation devices that generate electricity when exposed to sunlight, and can output the generated electricity to a battery 30 and a load device 40 connected to the first solar module 10 and the second solar module 20. Note that, although FIG. 1 illustrates an example in which the solar charging system 1 includes two solar modules, the first solar module 10 and the second solar module 20, the number of solar modules is not limited to two and may be three or more.

[0012] The first solar module 10 includes a first solar panel 11, a first DC-DC converter 12, a first sensor 13, and a first control unit 14. The second solar module 20 includes a second solar panel 21, a second DC-DC converter 22, a second sensor 23, and a second control unit 24.

[0013] The first solar panel 11 and the second solar panel 21 are devices capable of generating power according to the amount of sunlight irradiated onto them, and are typically an assembly of solar cells. The first solar panel 11 and the second solar panel 21 may be installed side by side in different locations in a planar configuration, or may be installed three-dimensionally in the same location, stacked one on top of the other. FIG. 2A shows an example of an arrangement in which the first solar panel 11 and the second solar panel 21 are installed side by side on the roof of a vehicle (a multi-system structure). FIG. 2B shows an example of an arrangement in which the first solar panel 11 and the second solar panel 21 are installed stacked on top of each other on the roof of a vehicle (a multi-junction structure).

[0014] The first solar panel 11 and the second solar panel 21 are preferably installed in locations where their solar radiation conditions are correlated. A correlation in solar radiation conditions can be expressed by, for example, having approximately the same amount of sunlight hitting both panels, or being able to predict the amount of sunlight hitting one panel from the amount of sunlight hitting the other panel. More specifically, for example, in the case of a multi-system structure (FIG. 2A) in which panels are installed side by side in different locations, a correlation in solar radiation conditions can be said to exist if the normal direction and curvature of the surface of the first solar panel 11 and the normal direction and curvature of the surface of the second solar panel 21 are the same or similar. When three or more solar panels are installed, it is desirable for each solar panel to have a correlation in solar radiation conditions with at least one other solar panel. On the other hand, in the case of a multi-junction structure (FIG. 2B) in which panels are installed in the same location, the normal direction and curvature of the surface of the first solar panel 11 and the second solar panel 21 are already the same, so a correlation in solar radiation conditions can be said to exist. However, in the case of such a multi-junction structure, the amount of light that passes through the first solar panel 11 and reaches the second solar panel 21 is less than the amount of light received by the first solar panel 11, so it is advisable to know in advance the light transmittance and light attenuation rate of the first solar panel 11 in order to estimate the amount of light received by the second solar panel 21 from the amount of light received by the first solar panel 11 (or vice versa). Note that solar panels can be installed on the hood, back door, trunk, windows, etc. in addition to the roof of a vehicle.

[0015] The first DC-DC converter 12 and the second DC-DC converter 22 are configured to independently control the power generation of the first solar panel 11 and the second solar panel 21. The first DC-DC converter 12 is a power converter that receives power generated by the first solar panel 11, converts the received power to a predetermined voltage, and outputs the power. The first DC-DC converter 12 controls the conversion and output of the generated power according to control (instructions) from the first control unit 14. The output of the first DC-DC converter 12 is supplied to the battery 30 and the load device 40. The second DC-DC converter 22 receives power generated by the second solar panel 21, converts the received power to a predetermined voltage, and outputs the power. The second DC-DC converter 22 controls the conversion and output of the generated power according to control (instructions) from the second control unit 24. The output of the second DC-DC converter 22 is supplied in parallel to the battery 30 and the load device 40 together with the output of the first DC-DC converter 12 .

[0016] The first sensor 13 and the second sensor 23 are configured to individually acquire the power generation states of the first solar panel 11 and the second solar panel 21. The first sensor 13 can acquire physical quantities such as the output voltage, output current, temperature, and generated power of the first solar panel 11 as the power generation state of the first solar panel 11. The second sensor 23 can acquire physical quantities such as the output voltage, output current, temperature, and generated power of the second solar panel 21 as the power generation state of the second solar panel 21. Various detection elements such as voltage sensors and current sensors can be used for the first sensor 13 and the second sensor 23.

[0017] The first control unit 14 and the second control unit 24 are configured to independently control the operations of the first DC-DC converter 12 and the second DC-DC converter 22. The first control unit 14 controls (and instructs) the first DC-DC converter 12 based on the power generation state of the first solar panel 11 acquired by the first sensor 13. This control includes control to output a voltage command value for power generation to the first DC-DC converter 12 and MPPT control to perform a scan process to search for the maximum power point of the first solar panel 11. The second control unit 24 controls (and instructs) the second DC-DC converter 22 based on the power generation state of the second solar panel 21 acquired by the second sensor 23. This control includes control to output a voltage command value for power generation to the second DC-DC converter 22 and MPPT control to perform a scan process to search for the maximum power point of the second solar panel 21. Well-known techniques can be used for the MPPT control of this embodiment.

[0018] The above-described first DC-DC converter 12 and first control unit 14 function as a power generation control unit that controls the power generation of the first solar panel 11. The above-described second DC-DC converter 22 and second control unit 24 function as a power generation control unit that controls the power generation of the second solar panel 21.

[0019] The battery 30 is a secondary battery configured to be rechargeable, such as a lithium-ion battery or a lead-acid battery. The battery 30 is connected to the first solar module 10 and the second solar module 20, and is configured so that it can be charged with power generated by the first solar panel 11 via the first DC-DC converter 12, and can be charged with power generated by the second solar panel 21 via the second DC-DC converter 22.

[0020] The load devices 40 are various devices that are connected to the battery 30 and operate on the power supplied from the battery 30.

[0021] The scan control device 50 monitors the power generation states of the first solar panel 11 and the second solar panel 21 in the first solar module 10 and the second solar module 20, and appropriately controls the scanning process of the MPPT control performed by the first DCDC converter 12 and the second DCDC converter 22. This scan control device 50 is typically configured as an electronic control unit (ECU) including a processor, memory, and input / output interface, and the processor reads and executes programs stored in the memory to realize the functions of a determination unit 51 and an instruction unit 52, which will be described below.

[0022] The determination unit 51 determines whether the power generation state of each of the first solar panel 11 and the second solar panel 21 satisfies a predetermined condition. Examples of the predetermined condition include the output voltage of the solar panel being within a predetermined range of values ​​that are estimated to be possible when the solar module is normal, or the power generated by the solar panel being equal to or greater than the minimum power value that is estimated to be possible under the current solar radiation conditions when the solar module is normal. The determination unit 51 may also determine whether it is time to perform a scan process on the first solar module 10 and the second solar module 20.

[0023] When the determination unit 51 determines that the power generation state of one of the first solar panel 11 and the second solar panel 21 does not satisfy a predetermined condition, the instruction unit 52 instructs the control unit of the one solar module to control the power generation of the solar panel using the results of the scan process of the other solar module. For example, when the power generation state of the first solar panel 11 does not satisfy a predetermined condition, the instruction unit 52 instructs the first control unit 14 of the first solar module 10 to control the power generation of the first solar panel 11 using the results of the scan process of the second solar module 20.

[0024] In addition, if the solar charging system 1 has three or more solar modules, if the judgment unit 51 determines that there is at least one solar module whose solar panel power generation state does not satisfy the specified conditions, the instruction unit 52 can transmit the results of the scanning process for the solar modules that satisfy the specified conditions and are correlated with the solar panel's solar panel radiation conditions to the solar modules that do not satisfy the specified conditions, and instruct them to control them. The control performed by the scan control device 50 will be described in detail below.

[0025] [control] Further referring to Fig. 3, the control performed in the solar charging system 1 equipped with a plurality of solar modules will be described. Fig. 3 is a flowchart showing the procedure of the scan process control executed by the scan control device 50 according to this embodiment. The scan process control illustrated in Fig. 3 is started, for example, when the solar charging system 1 is started, and is repeatedly executed until the solar charging system 1 is stopped.

[0026] (Step S301) The determination unit 51 of the scan control device 50 determines whether it is time to execute a scan process for multiple solar modules (including the first solar module 10 and the second solar module 20). This timing can be set in advance as a fixed timing so that the scan process can be executed periodically. The timing to execute the scan process may be notified to the scan control device 50 by the solar modules, or may be managed by the scan control device 50. If the determination unit 51 determines that it is time to execute the scan process (Yes in step S301), the process proceeds to step S302.

[0027] (Step S302) The judgment unit 51 of the scan control device 50 judges whether there is a solar module among the multiple solar modules (hereinafter referred to as the "solar module to be controlled") whose solar panel's power generation state does not satisfy a predetermined condition. Examples of cases where the predetermined condition is not satisfied include when the output voltage of the solar panel is significantly different from a pre-estimated voltage value, or when the power generation of the solar panel is lower than a pre-estimated minimum power value. As shown in FIG. 1, if the solar charging system 1 includes two solar modules, a first solar module 10 and a second solar module 20, the judgment unit 51 only needs to judge whether the power generation state of one of the solar panels of the first solar module 10 and the second solar module 20 does not satisfy the predetermined condition.

[0028] If the judgment unit 51 determines that there is a solar module whose solar panel power generation state does not satisfy the predetermined condition (step S302, Yes), the process proceeds to step S303. On the other hand, if the judgment unit 51 determines that there is no solar module whose solar panel power generation state does not satisfy the predetermined condition (step S302, No), the process proceeds to step S306.

[0029] (Step S303) The instruction unit 52 of the scan control device 50 controls (instructs) to execute a scan process on solar modules (hereinafter referred to as "non-control target solar modules") among the multiple solar modules, in which the power generation state of the solar panel other than the control target solar module satisfies a predetermined condition. This control (instruction) causes the MPPT control scan process to be executed on each of the non-control target solar modules. When the scan process is executed on the non-control target solar modules in accordance with the instruction from the instruction unit 52, the process proceeds to step S304.

[0030] (Step S304) The instruction unit 52 of the scan control device 50 acquires the results of the scan process performed on a specific solar module from the specific solar module among the solar modules not subject to control that have undergone the scan process. This specific solar module is a solar module that has a correlation in solar radiation conditions with the solar module subject to control. The correlation in solar radiation conditions has been described above. Once the instruction unit 52 acquires the scan process results for the specific solar module, the process proceeds to step S305.

[0031] (Step S305) The instruction unit 52 of the scan control device 50 instructs the control unit of the solar module to be controlled to control the power generation of the solar panel based on the results of the scan process of the specific solar module.

[0032] Specifically, for example, when the solar panel of the solar module to be controlled and the solar panel of a specific solar module have a multi-system structure (FIG. 2A), the instructing unit 52 can instruct the control unit of the solar module to be controlled to use the voltage command value of the DCDC converter at which the maximum power point is obtained in the solar panel of the specific solar module as the voltage command value of the DCDC converter of the solar module to be controlled. Also, for example, when the solar panel of the solar module to be controlled and the solar panel of the specific solar module have a multi-junction structure (FIG. 2B), the instructing unit 52 can instruct the control unit of the solar module to be controlled to derive a new voltage command value by reflecting the light transmittance, light attenuation rate, etc. of the solar panel in the voltage command value of the DCDC converter at which the maximum power point is obtained in the solar panel of the specific solar module, and use this derived new voltage command value as the voltage command value of the DCDC converter of the solar module to be controlled.

[0033] On the other hand, the instruction unit 52 of the scan control device 50 instructs the control units of the solar modules that are not the control targets to control the power generation of the solar panels based on the results of the scan processing obtained in each solar module.

[0034] When the instruction unit 52 issues instructions to control the power generation of the solar panels to the solar modules to be controlled and the solar modules not to be controlled, the process proceeds to step S301.

[0035] (Step S306) The instruction unit 52 of the scan control device 50 instructs the control units of all the solar modules included in the solar charging system 1 to control the power generation of the solar panels based on the results of the scan processing of each solar module. Once the instruction unit 52 has instructed all the solar modules to control the power generation of the solar panels, the process proceeds to step S301.

[0036] In the above-described processing flow, the process of determining whether it is time to perform the scanning process in step S301 may be performed after the process of determining whether there is a solar module whose solar panel power generation state does not satisfy the specified conditions in step S302.

[0037] In addition, in the specific example of step S305 in the processing flow described above, the instruction unit 52 performs control to directly instruct the voltage command value of the DC-DC converter that obtained the maximum power point in the solar panel of a specific solar module, without causing the solar module to perform a scan process. However, in addition to this control, for example, when the state of the solar module to be controlled is such that the sensor is normal but the MPPT control is unstable, the control may be such that the solar module to be controlled performs a scan process with a narrowed search range or widened search interval based on the voltage command value of the DC-DC converter that obtained the maximum power point in the solar panel of a specific solar module.

[0038] <Actions and Effects> As described above, according to the scan control device of one embodiment of the present disclosure, when there is a solar module (control target) that does not satisfy specified conditions among the multiple solar modules provided in the solar charging system, the power generation of the solar panel of the solar module (control target) that does not satisfy the specified conditions is controlled based on the results of the scan processing on the solar module (specific) that has a correlation in solar radiation conditions with the solar module (control target) that does not satisfy the specified conditions among the solar modules (non-control target) that satisfy the specified conditions.

[0039] With this control, even if a solar module in the solar charging system cannot accurately track the maximum power point because a sensor has broken down and is unusable, or because the system's control ECU is experiencing an abnormality such as unstable MPPT control, the control values ​​actually measured for other solar modules that are presumed to have similar solar radiation conditions and the same control direction can be used for the operation of that solar module. This makes it possible to avoid undesirable operations such as performing scanning with low accuracy, performing scanning frequently until satisfactory results are obtained, or performing scanning for long periods of time due to degraded tracking performance, thereby suppressing a decrease in the power generation efficiency of the solar charging system as a whole (improved controllability and increased power generation).

[0040] The above describes one embodiment of the present disclosure, but the present disclosure can be understood as a scan control device, a solar charging system equipped with a scan control device, a method executed by the scan control device, a program for executing the method, a computer-readable non-transitory recording medium storing the program, and a vehicle equipped with a solar charging system including a scan control device. [Industrial Applicability]

[0041] The scan control device of the present disclosure can be used in a solar charging system equipped with a plurality of solar modules. [Explanation of symbols]

[0042] 1 Solar charging system 10, 20 solar modules 11, 21 Solar panels 12, 22 DC-DC converter 13, 23 Sensor 14, 24 Control unit 30 Battery 40 Load equipment 50 Scan control device 51 Judgment Department 52 Instruction Section

Claims

1. A scan control device controls a scan process executed by each of the power generation control units to scan the output voltage of each of the solar panels to search for a maximum power point in a system in which a plurality of solar modules are connected, the scan process comprising: a solar panel; a sensor that acquires a power generation state of the solar panel; and a power generation control unit that controls power generation of the solar panel based on the power generation state of the solar panel; a determination unit that determines whether the power generation state of each of the solar panels satisfies a predetermined condition; a command unit that, when there is a solar module to be controlled for which the judgment unit has determined that the power generation state of the solar panel does not satisfy the specified condition, instructs the power generation control unit of the solar module to be controlled to control the power generation of the solar panel based on the results of the scan process for a specific solar module that is different from the solar module to be controlled.

2. the sensor acquires an output voltage of the solar panel as the power generation state; The scan control device according to claim 1 , wherein the predetermined condition includes that the output voltage of the solar panel is within a predetermined range of values ​​that can be assumed when the solar module is normal.

3. the sensor acquires the power generated by the solar panel as the power generation state; The scan control device according to claim 1 , wherein the predetermined condition includes that the power generated by the solar panel is equal to or greater than the minimum power value that can be attained under the current solar radiation conditions when the solar module is normal.

4. The scan control device according to claim 1 , wherein the specific solar module is a module having a correlation in terms of solar radiation conditions with the solar module to be controlled.

5. The scan control device according to claim 4 , wherein the solar module to be controlled and the specific solar module are stacked and joined together.

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