Power converter, processing system, processing method, and program

Abstract

To provide a power converter that can correct a maximum power point to another maximum power point which is more likely to be correct if the maximum power point is determined to be inaccurate.SOLUTION: A power converter comprises: a storage unit for storing a maximum power of a solar panel installed in the satellite and an output voltage of the solar panel at which the maximum power is obtained with respect to a lapsed time for one orbit of a satellite around a planet; a comparison unit for comparing measured values of maximum power of the solar panel and an output voltage of the solar panel during a next rotation with the stored maximum power and output voltage; and a control unit for controlling an extraction of power from the solar panel based on a comparison result.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present disclosure relates to a power converter, a processing system, a processing method, and a program. [Background technology]

[0002] Artificial satellites are used for various purposes. Patent Document 1 discloses a related technique for tracking the operating point of a solar cell to the maximum power point by MPPT control. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2017-153284 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology using MPPT control related to Patent Document 1, a hill climbing method is sometimes used, but the hill climbing method does not always accurately find the maximum power point. Therefore, there is a demand for a technology that can correct the maximum power point to a maximum power point that is considered to be more accurate when it is determined that the maximum power point is inaccurate.

[0005] An object of each aspect of the present disclosure is to provide a power converter, a processing system, a processing method, and a program that can solve the above-mentioned problems. [Means for solving the problem]

[0006] According to one aspect of the present disclosure, a power converter includes a memory unit that stores a maximum power of a solar panel provided on a satellite for a time elapsed during one orbit of the satellite orbiting a planet and an output voltage of the solar panel at which the maximum power is obtained, a comparison unit that compares measured values ​​of the maximum power of the solar panel and the output voltage of the solar panel during the next orbit with the stored maximum power and output voltage, and a control unit that controls the extraction of power from the solar panel based on the comparison result.

[0007] According to another aspect of the present disclosure, a processing system includes the power converter described above and a solar panel that supplies power to the power converter.

[0008] According to another aspect of the present disclosure, a processing method includes storing a maximum power of a solar panel provided on a satellite for a time elapsed during one orbit of the satellite orbiting a planet and an output voltage of the solar panel at which the maximum power is obtained, comparing measured values ​​of the maximum power of the solar panel and the output voltage of the solar panel during the next orbit with the stored maximum power and output voltage, and controlling the extraction of power from the solar panel based on the comparison result.

[0009] According to another aspect of the present disclosure, a program causes a computer to store a maximum power of a solar panel mounted on a satellite relative to the elapsed time of one orbit of the satellite orbiting a planet and an output voltage of the solar panel at which the maximum power is obtained, compare measured values ​​of the maximum power of the solar panel and the output voltage of the solar panel during the next orbit with the stored maximum power and output voltage, and control the extraction of power from the solar panel based on the comparison result. Effect of the Invention

[0010] According to each aspect of the present disclosure, when it is determined that the maximum power point is inaccurate, it is possible to correct it to a maximum power point that is believed to be more accurate. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 illustrates an example of a configuration of a processing system according to some embodiments of the present disclosure. [Diagram 2] FIG. 2 is a first diagram for explaining control of a maximum power point tracking (MPPT) method performed by a power converter according to some embodiments of the present disclosure. [Diagram 3] FIG. 2 is a second diagram for explaining MPPT control performed by a power converter according to some embodiments of the present disclosure. [Figure 4] FIG. 2 is a diagram showing the relationship between the elapsed time in the orbit of an artificial satellite orbiting a planet and the power generated by a solar panel on the artificial satellite. [Diagram 5] FIG. 2 is a diagram illustrating an example of a processing flow of a processing system according to some embodiments of the present disclosure. [Figure 6] FIG. 13 is a diagram illustrating an example of a configuration of a power converter according to another embodiment of the present disclosure. [Figure 7] FIG. 11 is a diagram illustrating an example of a processing flow of a power converter according to another embodiment of the present disclosure. [Figure 8] FIG. 1 is a schematic block diagram illustrating a configuration of a computer according to at least one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments will be described in detail with reference to the drawings. <Embodiment> (Processing System Configuration) A processing system 1 according to an embodiment of the present disclosure will be described with reference to the drawings. The processing system 1 is a system that is assumed to be an artificial satellite orbiting a planet and is equipped with a power converter that can efficiently extract power from a solar panel equipped on the artificial satellite.

[0013] 1 is a diagram illustrating an example of a configuration of a processing system 1 according to some embodiments of the present disclosure. As shown in FIG 1, the processing system 1 includes a solar panel 10, a power converter 20 (an example of a storage unit, an example of a comparison unit, and an example of a control unit), and a battery 30.

[0014] The solar panel 10 receives sunlight and generates power. The generated power is supplied to a battery via a power converter 20.

[0015] The power converter 20 generates power of a voltage suitable for each device from the power generated by the solar panel 10. The power converter 20 then charges the battery with the generated power.

[0016] FIG. 2 is a first diagram for explaining the control of the MPPT (Maximum Power Point Tracking) method performed by the power converter 20 according to some embodiments of the present disclosure. FIG. 3 is a second diagram for explaining the control of the MPPT method performed by the power converter 20 according to some embodiments of the present disclosure. The horizontal axis shown in FIG. 2 and FIG. 3 indicates the output voltage of the solar panel 10. The vertical axis on the left side shown in FIG. 2 and FIG. 3 indicates the output current of the solar panel 10. The vertical axis on the right side shown in FIG. 2 and FIG. 3 indicates the output power of the solar panel 10. The MPPT method control is a control that tracks the point of maximum power Pmax shown in FIG. 2. For example, the power converter 20 uses a hill climbing method to find the point of maximum power Pmax shown in FIG. 2 and the output voltage Vmp of the solar panel 10 in that case. Then, the power converter 20 can extract the maximum power from the solar panel 10 by actually extracting power from the solar panel 10 under the condition that the output voltage of the solar panel 10 is Vmp. However, when the hill climbing method is used, if there is a local maximum value other than the maximum value, for example as shown in Fig. 3, the local maximum value may be regarded as the maximum value. Also, when the hill climbing method is used, due to the influence of the output voltage change amount ΔV and the convergence in the calculation, another local maximum value or a convergence value may be regarded as the maximum value. In such a case, the power converter 20 cannot appropriately perform the MPPT control.

[0017] Therefore, since an artificial satellite orbiting a planet is assumed, the power converter 20 stores the output voltage Vmp and the maximum power Pmax adopted for each predetermined elapsed time of one orbit. When the power converter 20 obtains the maximum power Pmax for the output voltage Vmp by the hill climbing method, the power converter 20 compares the obtained maximum power Pmax with the maximum power Pmax for the same elapsed time in the orbit one orbit ago that has been stored. When the comparison result (i.e., the difference between the maximum power Pmax obtained by the hill climbing method and the maximum power Pmax adopted one orbit ago) exceeds a preset threshold value, the power converter 20 regards the output voltage Vmp adopted one orbit ago and the maximum power Pmax corresponding to that output voltage Vmp as the output voltage Vmp adopted one orbit ago and the maximum power Pmax corresponding to that output voltage Vmp, and extracts power from the solar panel 10. The power converter 20 converts the power thus extracted to a bus voltage (e.g., 50 volts) and charges the battery 30 with the converted power.

[0018] FIG. 4 is a diagram showing the relationship between the elapsed time on the orbit of an artificial satellite orbiting a planet and the power generated by the solar panel 10 of the artificial satellite. Since the orbit of the artificial satellite is known in advance, the time when the solar panel 10 receives sunlight in one orbit and the direction in which it receives the sunlight are known in advance, as shown in part (a) of FIG. 4. Therefore, it is possible to predict the power generated by the solar panel 10 at each elapsed time in one orbit, as shown in part (b) of FIG. 4. The first time the maximum power Pmax for the output voltage Vmp is calculated by the hill-climbing method, there is no maximum power Pmax stored one orbit ago, so the predicted power value may be used instead of the maximum power Pmax stored one orbit ago that has the same elapsed time.

[0019] The battery 30 stores the power that the power converter 20 extracts from the solar panel 10 under MPPT control, or supplies the stored power to a load (not shown).

[0020] (Processing performed by the processing system) The above-described processing performed by the processing system 1 is merely an example, and the processing performed by the processing system 1 according to an embodiment of the present disclosure is not limited to the above-described processing. For example, the processing system 1 may perform the processing described below.

[0021] Fig. 5 is a diagram showing an example of a processing flow of the processing system 1 according to some embodiments of the present disclosure. Next, a process of correcting the maximum power Pmax to an appropriate maximum power Pmax when the power converter 20 of the processing system 1 determines that the maximum power Pmax for the output voltage Vmp obtained by the hill climbing method is inappropriate when performing MPPT control will be described with reference to Fig. 5. Note that the process shown in Fig. 5 is a process executed every time MPPT control is performed using the maximum power Pmax obtained by the hill climbing method, which is repeatedly performed in one revolution.

[0022] The power converter 20 measures the output voltage Vmp of the solar panel 10 and the maximum power Pmax for that output voltage Vmp using the hill climbing method (step S1). The power converter 20 determines whether or not the error between the output voltage Vmp measured using the hill climbing method and the previous Vmp (one cycle ago, a predicted value in the case of the first time) is greater than a threshold value (step S2).

[0023] When the power converter 20 determines that the error between the output voltage Vmp measured using the hill climbing method and the previous output voltage Vmp (one cycle ago, predicted value in the case of the first time) is equal to or less than the threshold value (NO in step S2), it executes MPPT control using the output voltage Vmp measured using the hill climbing method (step S3). Then, after a certain time, the power converter 20 stores the adopted output voltage Vmp, maximum power Pmax, and the elapsed time during control (step S4). Then, the power converter 20 ends the process.

[0024] In addition, when the power converter 20 determines that the error between the output voltage Vmp measured using the hill climbing method and the previous Vmp (one cycle ago, predicted value in the case of the first time) is greater than the threshold value (YES in step S2), it determines whether the maximum power Pmax measured using the hill climbing method is greater than the previous maximum power Pmax (step S5).

[0025] When the power converter 20 determines that the maximum power Pmax measured using the hill-climbing method is equal to or less than the previous maximum power Pmax (NO in step S5), it performs constant voltage control so that the output voltage Vmp becomes the previous output voltage Vmp (step S6).Then, the power converter 20 proceeds to the process of step S3.

[0026] Furthermore, when the power converter 20 determines that the maximum power Pmax measured using the hill-climbing method is greater than the previous maximum power Pmax (YES in step S5), it proceeds to the process of step S3 without performing the process of step S6.

[0027] (advantage) The processing system 1 according to an embodiment of the present disclosure has been described above. In the processing system 1, the power converter 20 stores the maximum power Pmax of the solar panel 10 provided on the artificial satellite for the elapsed time of one orbit of the artificial satellite orbiting a planet, and the output voltage Vmp of the solar panel 10 at which the maximum power Pmax is obtained, compares the measured values ​​of the maximum power Pmax of the solar panel 10 and the output voltage Vmp of the solar panel 10 during the next orbit with the stored maximum power Pmax and output voltage Vmp, and controls the extraction of power from the solar panel 10 based on the comparison result. When the maximum power point is determined to be inaccurate, this power converter can correct it to a maximum power point that is considered to be more correct.

[0028] 6 is a diagram illustrating an example of a configuration of a power converter 300 according to another embodiment of the present disclosure. The power converter 300 includes a storage unit 301, a comparison unit 302, and a control unit 303, as shown in FIG.

[0029] A memory unit 301 stores the maximum power of a solar panel provided on a satellite for the elapsed time of one orbit of the satellite orbiting a planet, and the output voltage of the solar panel at which the maximum power is obtained. A comparison unit 302 compares the measured values ​​of the maximum power of the solar panel and the output voltage of the solar panel during the next orbit with the stored maximum power and output voltage. A control unit 303 controls the extraction of power from the solar panel based on the comparison result.

[0030] Each of the storage unit 301, the comparison unit 302, and the control unit 303 can be realized, for example, by using the functions of the power converter illustrated in FIG.

[0031] 7 is a diagram showing an example of a processing flow of the power converter 300 according to another embodiment of the present disclosure. Next, processing of the power converter 300 according to another embodiment of the present disclosure will be described with reference to FIG.

[0032] The memory unit 301 stores the maximum power of a solar panel provided on a satellite for the elapsed time of one orbit of the satellite orbiting a planet, and the output voltage of the solar panel at which the maximum power is obtained (step S101). The comparison unit 302 compares the measured values ​​of the maximum power of the solar panel and the output voltage of the solar panel during the next orbit with the stored maximum power and output voltage (step S102). The control unit 303 controls the extraction of power from the solar panel based on the comparison result (step S103).

[0033] Hereinabove, a power converter 300 according to another embodiment of the present disclosure has been described. When the maximum power point is determined to be inaccurate, the power converter 300 can correct the maximum power point to one that is considered to be more accurate.

[0034] It should be noted that the order of the processes in the embodiments of the present disclosure may be changed as long as appropriate processes are performed.

[0035] Although the embodiments of the present disclosure have been described, the above-mentioned processing system 1, the power converter 20, and other control devices may have a computer system therein. The above-mentioned process steps are stored in a computer-readable recording medium in the form of a program, and the above-mentioned process is performed by the computer reading and executing the program. Specific examples of computers are shown below.

[0036] 8 is a schematic block diagram showing the configuration of a computer according to at least one embodiment. As shown in FIG. 8, the computer 5 includes a CPU (Central Processing Unit) 6, a main memory 7, a storage 8, and an interface 9.

[0037] For example, the above-mentioned processing system 1, power converter 20, and other control devices are each implemented in a computer 5. The operations of each of the above-mentioned processing units are stored in the storage 8 in the form of a program. The CPU 6 reads the program from the storage 8, loads it in the main memory 7, and executes the above-mentioned processes in accordance with the program. The CPU 6 also secures storage areas in the main memory 7 corresponding to each of the above-mentioned storage units in accordance with the program. The CPU 6 of the present disclosure may be a controller.

[0038] Examples of the storage 8 include a hard disk drive (HDD), a solid state drive (SSD), a magnetic disk, a magneto-optical disk, a compact disc read only memory (CD-ROM), a digital versatile disc read only memory (DVD-ROM), and a semiconductor memory. The storage 8 may be an internal medium directly connected to the bus of the computer 5, or an external medium connected to the computer 5 via an interface 9 or a communication line. In addition, when the program is distributed to the computer 5 via a communication line, the computer 5 that receives the program may load the program into the main memory 7 and execute the above-mentioned process. In at least one embodiment, the storage 8 is a non-transitory tangible storage medium.

[0039] The program may also realize some of the functions described above. Furthermore, the program may be a file that can realize the functions described above in combination with a program already recorded in the computer system, that is, a so-called differential file (differential program).

[0040] Although some embodiments of the present disclosure have been described, these embodiments are merely examples and do not limit the scope of the disclosure. Various additions, omissions, substitutions, and modifications may be made to these embodiments without departing from the spirit of the disclosure.

[0041] Note that some or all of the above-described embodiments can be described as, but are not limited to, the following supplementary notes.

[0042] (Appendix 1) A storage unit that stores a maximum power of a solar panel provided on the artificial satellite for a time elapsed during one orbit of the artificial satellite orbiting a planet, and an output voltage of the solar panel at which the maximum power is obtained; a comparison unit that compares the measured values ​​of the maximum power and the output voltage of the solar panel during the next rotation with the stored maximum power and the output voltage; A control unit that controls the extraction of power from the solar panel based on a result of the comparison; A power converter comprising:

[0043] (Appendix 2) The control unit is As a control for extracting power from the solar panel, When the difference between the output voltages is greater than a threshold value in the comparison result and the maximum power in the next cycle is equal to or less than the maximum power in the previous cycle, a constant voltage control is performed so that the maximum power becomes the maximum power in the previous cycle, and then a maximum power point tracking (MPPT) control is performed. 2. A power converter as claimed in claim 1.

[0044] (Appendix 3) The control unit is As a control for extracting power from the solar panel, When the difference between the output voltages is equal to or smaller than a threshold value in the comparison result, MPPT control is performed. 3. A power converter as claimed in claim 1 or 2.

[0045] (Appendix 4) The control unit is As a control for extracting power from the solar panel, When the difference between the output voltages is greater than a threshold value in the comparison result and the maximum power in the next cycle is greater than the maximum power in the previous cycle, MPPT control is performed. 4. The power converter of claim 1 ,

[0046] (Appendix 5) A power converter according to any one of Supplementary Note 1 to Supplementary Note 4; a solar panel for supplying power to the power converter; A processing system comprising:

[0047] (Appendix 6) storing a maximum power of a solar panel provided on the satellite for a time elapsed during one orbit of the satellite orbiting a planet, and an output voltage of the solar panel at which the maximum power is obtained; comparing the measured maximum power of the solar panel and the output voltage of the solar panel during the next revolution with the stored maximum power and output voltage; Based on a result of the comparison, control is performed to extract power from the solar panel. A processing method comprising:

[0048] (Appendix 7) On the computer, storing a maximum power of a solar panel provided on the satellite for a time elapsed during one orbit of the satellite orbiting a planet, and an output voltage of the solar panel at which the maximum power is obtained; comparing the measured maximum power of the solar panel and the output voltage of the solar panel during the next revolution with the stored maximum power and output voltage; Based on a result of the comparison, control is performed to extract power from the solar panel. A program that executes the following. [Explanation of symbols]

[0049] 1. Processing system 5. Computers 6. CPU 7. Main memory 8. Storage 9. Interface 10. Solar panel 20, 300... Power converter 30. Battery 301...Storage section 302 Comparison section 303 Control section

Claims

1. a storage unit that stores a maximum power of a solar panel provided on the artificial satellite for a time elapsed during one orbit of the artificial satellite orbiting a planet, and an output voltage of the solar panel at which the maximum power is obtained; a comparison unit that compares the measured values ​​of the maximum power and the output voltage of the solar panel during the next rotation with the stored maximum power and the output voltage; A control unit that controls the extraction of power from the solar panel based on a result of the comparison; A power converter comprising:

2. The control unit is As a control for extracting power from the solar panel, When the difference between the output voltages is greater than a threshold value in the comparison result and the maximum power in the next cycle is equal to or less than the maximum power in the previous cycle, a constant voltage control is performed so that the maximum power in the previous cycle is reached, and then a maximum power point tracking (MPPT) control is performed.

2. The power converter of claim 1.

3. The control unit is As a control for extracting power from the solar panel, When the difference between the output voltages is equal to or smaller than a threshold value in the comparison result, MPPT control is performed.

2. The power converter of claim 1.

4. The control unit is As a control for extracting power from the solar panel, When the difference between the output voltages is greater than a threshold value in the comparison result and the maximum power in the next cycle is greater than the maximum power in the previous cycle, control is performed using an MPPT method.

2. The power converter of claim 1.

5. A power converter according to any one of claims 1 to 4; a solar panel for supplying power to the power converter; A processing system comprising:

6. storing a maximum power of a solar panel provided on the satellite for a time elapsed during one revolution of the satellite orbiting a planet, and an output voltage of the solar panel at which the maximum power is obtained; comparing the measured maximum power of the solar panel and the output voltage of the solar panel during the next revolution with the stored maximum power and output voltage; Based on a result of the comparison, control is performed to extract power from the solar panel. A processing method comprising:

7. On the computer, storing a maximum power of a solar panel provided on the satellite for a time elapsed during one revolution of the satellite orbiting a planet, and an output voltage of the solar panel at which the maximum power is obtained; comparing the measured maximum power of the solar panel and the output voltage of the solar panel during the next revolution with the stored maximum power and output voltage; Based on a result of the comparison, control is performed to extract power from the solar panel. A program that executes the following.

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