Charge control device and charge control program

Abstract

A charge control device 203 controls a solar panel, which generates electric power from sunlight, in a mobile body provided with a battery for receiving and storing supply of electric power from at least one of the solar panel and a generator that converts mechanical energy into electric energy. The charge control device 203 comprises: a measurement unit 207 that measures the voltage of the battery; and a control unit 205 that controls the supply of electric power from the solar panel to the battery so that the measured voltage value of the battery is between an upper-limit voltage value at which charging of the battery is permitted and a predetermined voltage value of the battery at which the generator starts charging the battery.

Description

Charging control device and charging control program

[0001] The present invention relates to a charging control device and a charging control program that control a mobile object equipped with a battery that receives and stores power from at least one of a generator that converts mechanical energy into electrical energy or a solar panel that generates power from sunlight.

[0002] A technology for attaching a solar panel to a vehicle and supplying the vehicle with power generated by the solar panel has been known. For example, Patent Document 1 (JP-A-2005-102626) discloses a solar system for a vehicle. The solar system includes a solar panel that generates power using sunlight, a first battery that is rechargeable and dischargeable, a second battery that is rechargeable and dischargeable, a power converter that outputs the power generated by the solar panel to the first battery, a load that consumes the power, a first relay that detachably connects the first battery to the load, and a second relay that detachably connects the second battery to the load. The first relay disconnects the first battery from the load while the amount of charge stored in the second battery is greater than a predetermined threshold in a power supply state in which vehicle travel is not permitted, and the second relay disconnects the second battery from the load while the engine is idling and stopped in a power supply state in which vehicle travel is permitted.

[0003] Furthermore, Patent Document 2 discloses a method for suppressing torque fluctuations of an internal combustion engine by increasing the load of a generator on the internal combustion engine. In this method, the internal combustion engine is equipped with a generator, which supplies electric power to a storage battery mounted on a vehicle. When the internal combustion engine is operating at an engine speed equal to or lower than a predetermined speed, the generator generates electricity at a timing that absorbs fluctuations in engine output torque. Then, the engine speed is detected, and if it is determined that the detected engine speed exceeds the predetermined speed, charging of the storage battery is stopped when the charge capacity exceeds a predetermined value.

[0004] Patent Literature 3 discloses a vehicle cooperative control device that improves energy efficiency through energy storage. This vehicle cooperative control device includes an internal combustion engine, a generator, an air conditioner, and energy storage means for storing electric power generated by the generator and cold energy generated by the air conditioner. It also includes environmental condition acquisition means for acquiring driving environment conditions along the vehicle's driving route, and cooperative control means. The cooperative control means predicts a period during which power can be generated by the generator or cold energy can be generated by the air conditioner based on the driving environment conditions and the amount of stored energy. If a single regeneration period does not last a predetermined time, it prioritizes power generation by the generator over cold energy generation by the air conditioner during that regeneration period.

[0005] JP 2019-088156 A JP 2012-002068 A JP 2005-212564 A

[0006] Generally, vehicles such as passenger cars and trucks are equipped with an auxiliary battery (e.g., a 12V or 24V lead battery) to supply power to electrical equipment such as air conditioners and headlights, as well as a generator (hereinafter also referred to as an "alternator") that converts mechanical energy into electrical energy. The use of electrical equipment in these vehicles consumes power from the auxiliary battery, but the vehicle is configured to constantly monitor the voltage value of the auxiliary battery, and when the voltage of the auxiliary battery falls below a certain value, the alternator is activated to supply the shortage of power to the electrical equipment or the auxiliary battery, thereby maintaining the voltage of the auxiliary battery constant.

[0007] However, because an alternator utilizes the mechanical energy of an internal combustion engine (e.g., a gasoline engine), operating the alternator places a load on the internal combustion engine to generate electricity other than for the drivetrain. As a result, fuel economy deteriorates. To improve fuel economy of a vehicle, it is desirable to minimize the operation of the alternator. Therefore, one possible method to reduce alternator operation is to supply power from a solar panel to charge the auxiliary battery.

[0008] On the other hand, if the solar panel continues to charge the auxiliary battery, it may overcharge, which may cause problems with the auxiliary battery (for example, deterioration of the auxiliary battery). For this reason, it is necessary to control the charging of the auxiliary battery from the solar panel to a range that does not cause overcharging.

[0009] Patent Documents 1 to 3 disclose technologies related to mobile objects equipped with solar panels, but do not consider the improvement of fuel efficiency by reducing the operation of the alternator as described above, nor the prevention of overcharging of the auxiliary battery. Furthermore, since the solar power generation system is designed to be installed in the vehicle from the beginning, retrofitting of the solar power generation system to the vehicle is not considered. Therefore, it is not possible to solve the problems that may arise when retrofitting a solar power generation system to trucks, buses, etc. that are already in use.

[0010] The present invention has been made in consideration of these circumstances, and aims to provide a charging control device and a charging control program that can control the supply of power from a solar panel to a battery, thereby suppressing power generation by a generator and improving fuel efficiency, thereby contributing to solving the social issue of carbon neutrality and preventing battery deterioration.

[0011] (1) In order to achieve the above object, the present invention provides the following means: That is, a charge control device according to one aspect of the present invention is a charge control device for a mobile body equipped with a battery that receives and stores power from at least one of a generator that converts mechanical energy into electrical energy and a solar panel that generates power from sunlight, the charge control device controlling the solar panel, and is characterized by comprising: a measurement unit that measures the voltage of the battery; and a control unit that controls the supply of power from the solar panel to the battery so that the measured battery voltage value is a voltage value between an upper limit voltage value at which charging of the battery is permitted and a predetermined battery voltage value at which the generator starts charging the battery.

[0012] In this way, the supply of power from the solar panel to the battery is controlled so that the battery voltage value is between the upper limit voltage value at which charging to the battery is permitted and the battery voltage value at which the generator begins charging the battery.This makes it possible to suppress power generation by the generator, improve fuel efficiency, and prevent battery deterioration.

[0013] (2) In addition, in the charging control device according to (1) above, the control unit is characterized in that it has a switch unit or a function for determining ON / OFF of supply, which stops the supply of power from the solar panel to the battery when the voltage value of the battery exceeds an upper threshold that is lower than the upper limit voltage value at which charging of the battery is permitted, and supplies power from the solar panel to the battery when the voltage value of the battery falls below a predetermined lower threshold that is higher than the voltage value of the battery at which the generator starts charging the battery.

[0014] In this way, the supply of power from the solar panel to the battery is stopped when the battery voltage exceeds an upper threshold that is lower than the upper limit voltage that allows charging to the battery, making it possible to prevent the battery from exceeding the allowable range of charging. On the other hand, the supply of power from the solar panel to the battery is started when the battery voltage falls below a predetermined lower threshold that is higher than the battery voltage that allows the generator to start charging the battery, making it possible to minimize the need for the generator to operate and charge the battery. As a result, it is possible to suppress power generation by the generator, improve fuel efficiency, and prevent battery degradation.

[0015] (3) Furthermore, in the charging control device according to (1) or (2) above, when the moving body starts, the measuring unit measures the voltage of the battery without supplying power from the solar panel to the battery, and the control unit sets the measured voltage value as the voltage value of the battery at which the generator starts charging the battery.

[0016] This configuration allows automatic calibration of the battery voltage value at which the generator starts charging the battery. That is, the battery voltage value at startup is set as the lower limit voltage value, and a lower limit threshold value higher than the lower limit voltage value is set, thereby suppressing power generation by the generator and improving fuel efficiency.

[0017] (4) Furthermore, in the charging control device according to any one of (1) to (3) above, the control unit supplies power from the solar panel to the battery by Maximum Power Point Tracking (MPPT).

[0018] This configuration extracts current at the output voltage that maximizes the power from the solar panel, making it possible to supply power under optimal conditions according to the amount of solar radiation.

[0019] (5) Furthermore, in the charging control device according to (4) above, the control unit is characterized in that, when the voltage value of the battery is within a predetermined range between the upper limit voltage value and the predetermined voltage value of the battery at which the generator starts charging the battery, the control unit adjusts the ratio of power supplied from the solar panel to the battery based on the voltage value of the battery.

[0020] With this configuration, the ratio of power supplied from the solar panel to the battery is adjusted, and the battery voltage value can be controlled so that it is between the upper limit voltage value at which charging to the battery is permitted and the predetermined battery voltage value at which the generator begins charging the battery.

[0021] In the above, the "power ratio" refers to the ratio of the power supplied to the battery to the power output from the solar panel. In other words, the "power ratio" refers to the proportion of the power output from the solar panel that is supplied to the battery.

[0022] (6) Furthermore, in the charging control device according to (5) above, the control unit adjusts the power supplied from the solar panel to the battery so that, when the voltage value of the battery is within the predetermined range, the power ratio becomes smaller as the voltage value of the battery increases (in other words, the power ratio becomes larger as the voltage value of the battery decreases).

[0023] This configuration prevents the battery voltage value from becoming higher than the upper limit voltage value at which charging to the battery is permitted, and prevents the battery voltage value from becoming lower than the battery voltage value at which the generator begins charging the battery.

[0024] (7) Furthermore, the charging control device according to any one of (1) to (6) above controls a plurality of solar panels, and the control unit selects the solar panel with the greatest instantaneous maximum power or a combination of solar panels with the greatest instantaneous maximum power, and controls the supply of power to the battery.

[0025] This configuration allows for the optimal combination of multiple solar panels, and makes it possible to control the charging voltage depending on whether or not each solar panel is generating power, thereby preventing the battery from overcharging.

[0026] (8) Furthermore, the charging control device according to any one of (1) to (7) above is characterized in that it stops or reduces the supply of power from the solar panel to the battery when the moving body is decelerating or operating under its own weight.

[0027] In this way, stopping or reducing the power supply from the solar panel will consume more battery power, which indirectly allows the generator to operate, resulting in regenerative braking and reduced brake pad wear.

[0028] (9) Furthermore, in the charging control device according to any one of (1) to (8) above, the control unit is characterized in that it acquires information indicating the state of the mobile body from a network installed in the mobile body, and controls the supply of power from the solar panel to the battery based on the acquired information.

[0029] With this configuration, the supply of power from the solar panel to the battery is controlled according to the state of the mobile body, for example, whether the mobile body is decelerating, operating under its own weight, or stopped, whether the air conditioner or headlights are in use, or whether the battery is fully charged.This makes it possible to reduce power generation by the generator, improve fuel efficiency, and prevent battery deterioration.

[0030] (10) Furthermore, in the charging control device according to (9) above, the control unit is characterized in that it controls the supply of power from the solar panel to the battery based on information indicating the state of the generator obtained from the network.

[0031] This configuration makes it possible to control the supply of power from the solar panel to the battery depending on the state of the generator, i.e., whether the generator is running and charging the battery, or whether the generator is idle and not charging the battery, thereby making it possible to prevent overcharging of the battery.

[0032] (11) Furthermore, in the charging control device according to any one of (1) to (10) above, the control unit is characterized in that it calculates the voltage of the battery based on the voltage of the battery when no power is supplied from the solar panel to the battery, the voltage of the battery when power is supplied from the solar panel to the battery, and the current from the battery.

[0033] This configuration makes it possible to avoid the influence of voltage drop in the harness and to accurately calculate the battery voltage.

[0034] (12) In addition, in the charging control device according to any one of (1) to (11) above, the control unit is characterized in that it controls the supply of power from the solar panel to the battery when the mobile body is not operating.

[0035] In this way, when the vehicle is not operating, the battery consumes less power and is expected to charge quickly. In this state, controlling the power supply from the solar panel to the battery can prevent battery deterioration.

[0036] (13) Furthermore, in the charging control device according to any one of (1) to (12) above, the control unit is characterized in that, when the voltage value of the battery exceeds the upper limit value of the rated voltage of the battery, the control unit stops the supply of power from the solar panel to the battery.

[0037] In this way, if the battery voltage value exceeds the upper limit of the rated voltage of the battery, the supply of power from the solar panel to the battery is stopped, making it possible to use the battery safely.

[0038] (14) Furthermore, a charging control program according to one aspect of the present invention is a charging control program for controlling a mobile body equipped with a battery that receives and stores power from at least one of a generator that converts mechanical energy into electrical energy or a solar panel that generates power using sunlight, and is characterized in that the program causes a computer to execute a process of measuring the voltage of the battery and a process of controlling the supply of power from the solar panel to the battery so that the measured battery voltage value is a voltage value between an upper limit voltage value at which charging to the battery is permitted and a predetermined voltage value of the battery at which the generator starts charging the battery.

[0039] In this way, the supply of power from the solar panel to the battery is controlled so that the battery voltage value is between the upper limit voltage value at which charging to the battery is permitted and the battery voltage value at which the generator begins charging the battery.This makes it possible to suppress power generation by the generator, improve fuel efficiency, and prevent battery deterioration.

[0040] (15) The charging control program according to (14) further includes a process for stopping the supply of power from the solar panel to the battery when the voltage value of the battery exceeds an upper threshold that is lower than the upper limit voltage value at which charging of the battery is permitted, and for supplying power from the solar panel to the battery when the voltage value of the battery falls below a predetermined lower threshold that is higher than the voltage value of the battery at which the generator starts charging the battery.

[0041] In this way, the supply of power from the solar panel to the battery is stopped when the battery voltage exceeds an upper threshold that is lower than the upper limit voltage that allows charging to the battery, making it possible to prevent the battery from exceeding the allowable range of charging. On the other hand, the supply of power from the solar panel to the battery is started when the battery voltage falls below a predetermined lower threshold that is higher than the battery voltage that allows the generator to start charging the battery, making it possible to minimize the need for the generator to operate and charge the battery. As a result, it is possible to suppress power generation by the generator, improve fuel efficiency, and prevent battery degradation.

[0042] The charge control device and the charge control program of the present invention can reduce power generation by the generator, improve fuel efficiency, contribute to solving the social issue of carbon neutrality, and prevent battery deterioration. Furthermore, by extending the period during which the generator is not generating power, the life of the generator itself can be extended.

[0043] Fig. 5 is a block diagram showing a schematic configuration of a vehicle as a mobile body equipped with a solar power generation device. Fig. 6 is a block diagram showing a schematic configuration of a charge control device. Fig. 7 is a flowchart showing the operation of a charge control device according to a first embodiment. Fig. 8 is a diagram showing waveforms of voltage changes in the operation shown in the flowchart of Fig. 3. Fig. 9 is a flowchart showing the operation of a charge control device according to a second embodiment. Fig. 10 is a diagram showing waveforms of an example of changes in the voltage value D [V] of the battery and changes in the power P [W] supplied from the solar panel to the battery in the operation shown in the flowchart of Fig. 5.

[0044] [First embodiment] The inventors noticed that when the alternator is operating, a load is placed on the internal combustion engine to generate electricity other than for the drive system, resulting in a decrease in fuel efficiency. Therefore, by supplying power from a solar panel to charge an auxiliary battery, the operation of the alternator can be reduced. However, if the auxiliary battery continues to be charged from the solar panel, it may be overcharged, causing a malfunction in the auxiliary battery. They discovered that by controlling the supply of power from the solar panel to the battery, it is possible to suppress the generation of electricity by the generator, thereby improving fuel efficiency and preventing battery deterioration, and thus arrived at the present invention.

[0045] In other words, one aspect of the present invention provides a charging control device for a mobile body equipped with a battery that receives and stores power from at least one of a generator that converts mechanical energy into electrical energy and a solar panel that generates power from sunlight, the charging control device controlling the solar panel, and characterized by comprising: a measuring unit that measures the voltage of the battery; and a control unit that controls the supply of power from the solar panel to the battery so that the measured battery voltage value is a voltage value between the upper limit voltage value at which charging to the battery is permitted and a predetermined voltage value of the battery at which the generator starts charging the battery.

[0046] As a result, the inventors have realized that the power generation by the generator can be suppressed to improve fuel efficiency and also to prevent deterioration of the battery. Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.

[0047] [Configuration] Figure 1 is a block diagram showing the schematic configuration of a vehicle as a mobile body equipped with a solar power generation system. As shown in Figure 1, vehicle 100 includes a battery 101 that supplies power to various electrical components and internal combustion engine auxiliaries (not shown). Vehicle 100 also includes an on-board alternator 103 that generates power from the rotational force of the internal combustion engine (not shown). Vehicle 100 also includes a solar power generation system 200 that can be installed as an add-on. Solar power generation system 200 includes one or more solar panels 201 and a charge control device 203 that controls charging of battery 101 using power generated by solar panels 201.

[0048] 2 is a block diagram showing a schematic configuration of the charge control device. The charge control device 203 has a control unit 205 that suppresses power generation by the on-board alternator 103 while avoiding overcharging (overvoltage) of the battery 101, and a measurement unit 207 that measures (detects) the voltage of the battery 101. The charge control device 203 also has a switch unit 209 that turns on / off charging from the solar panel 201 to the battery 101 under the control of the control unit 205. Note that the same function can also be provided to the control unit 205 without providing the switch unit 209.

[0049] [Measures to Avoid Overcharging] To avoid overcharging of the battery, either a method in which the measurement unit 207 measures the voltage at the terminal ends of the battery 101 (four-terminal method) or a method in which the voltage of the battery 101 is acquired via the vehicle's CAN / LIN communication can be applied. When the measurement unit 207 measures the voltage of the battery 101, it is necessary to avoid the influence of voltage drop due to the harness. Therefore, a method can be applied in which the accurate voltage between the terminals of the battery 101 is calculated using the voltage of the battery 101 when the power supply from the solar panel 201 to the battery 101 is turned off and the current and voltage when the power supply from the solar panel 201 to the battery 101 is turned on.

[0050] [Suppression of Power Generation by Alternator] To suppress power generation by the on-board alternator 103, the control unit 205 has a function of detecting whether power generation by the on-board alternator 103 is on or off. One method for detecting whether power generation by the on-board alternator 103 is on or off is for the control unit 205 to detect the power generation voltage of the on-board alternator 103 based on the voltage of the battery 101 when the internal combustion engine is operating without supplying power from the solar panel 201 to the battery 101. Another method is to obtain information on the power generation status or control voltage of the on-board alternator 103 using a communication means such as CAN / LIN communication provided in the vehicle 100. Another method is to detect the state of the vehicle 100 using a communication means such as CAN / LIN communication of the vehicle 100, and associate the information on the power generation status or control voltage of the on-board alternator 103 with the information, thereby detecting the power generation voltage of the on-board alternator 103. Here, the state of the vehicle 100 includes, for example, acceleration / braking / stopping, and operation of the air conditioner, electric fan, etc. Furthermore, it also includes devices that use a lot of power from the auxiliary battery, such as headlights.

[0051] [Avoiding Overcharging and Suppressing Power Generation by Alternator through Charging Control] The charging control device according to this embodiment controls charging of battery 101 from solar panel 201, thereby avoiding overcharging and suppressing power generation by on-board alternator 103. That is, control unit 205 controls charging of battery 101 from solar panel 201 so that the voltage range of battery 101 satisfies the following mathematical formula 1.

[0052] [Formula 1] (power generation start threshold voltage of on-board alternator 103)<(voltage value of battery 101)<(upper rated voltage value of battery)

[0053] From the viewpoint of suppressing power generation by the on-board alternator 103, the battery 101 can be charged from the solar panel 201 so as to satisfy the following formula 2.

[0054] [Equation 2] (power generation start threshold voltage of the in-vehicle alternator 103)<(voltage value of the battery 101)

[0055] Furthermore, from the viewpoint of avoiding overcharging of the battery 101, charging of the battery 101 from the solar panel 201 can be stopped so as to satisfy the following formula 3.

[0056] [Formula 3] (Voltage value of battery 101)<(Upper limit threshold lower than the upper limit voltage value at which charging to the battery is permitted)

[0057] Furthermore, the control unit 205 sets the target voltage value to a value calculated by the following equation 4 so as to be able to respond to dynamic fluctuations in the power generation of the on-board alternator 103 while suppressing deterioration of the battery 101 .

[0058] [Formula 4] (power generation start threshold voltage value + upper limit of rated voltage of battery) ÷ 2 = (target voltage value)

[0059] In addition, in order to realize these functions, the control unit 205 has one or more of the functions listed below.

[0060] (A) When power generation from multiple solar panels 201 is aggregated or linked, the amount of power supplied to the battery 101 is increased or decreased by turning on or off power generation at each solar panel 201.

[0061] (A-1) In order to suppress deterioration of the battery 101, power generation by the solar panel 201, which has a large instantaneous maximum power, is stopped.

[0062] (A-2) To approach the target voltage, the combination is optimized based on the instantaneous power generated by the multiple solar panels 201. Here, the algorithm for detecting the instantaneous power generated by each solar panel 201 selects the panel with the instantaneous power generated with the smallest slope based on the dynamic amount of change in the voltage of the battery 101 due to the power supply.

[0063] (B) When power is generated from a single solar panel 201 (string), the amount of power supplied to the battery is increased or decreased by starting or stopping power generation from the solar panel 201.

[0064] (B-1) The ON / OFF is controlled above the power generation start threshold voltage of the on-board alternator 103 and below the upper limit of the rated voltage of the battery 101. This is so-called bang-bang control.

[0065] (C) As a preview control or a feedforward control, the target voltage is changed in advance based on the control state of the vehicle 100. (C-1) The power generation of the on-board alternator 103 is suppressed to the maximum extent.

[0066] (C-2) Conversely, the on-board alternator 103 is intentionally operated. For example, in order to suppress vapor lock and brake pad wear when going downhill, the power supply from the solar panel 201 is stopped and the voltage of the battery 101 is lowered, thereby operating the on-board alternator 103. Here, the state of the vehicle 100 is detected by communication such as CAN / LIN communication of the vehicle 100, and the on-board alternator 103 is operated according to the detection result.

[0067] (D) In ​​addition to (or in parallel with) maximum power point tracking (MPPT) control, the solar power generation device 200 suppresses the power generation so as to track a target voltage. Here, maximum power point tracking control is control that automatically determines the optimal "current x voltage value (maximum power point or optimal operating point)" that maximizes the output when the solar panel 201 generates power. The optimal operating point of the solar panel 201 fluctuates depending on the installation location and weather, but MPPT makes it possible to automatically obtain maximum output.

[0068] [Operation] Figure 3 is a flowchart showing the operation of the charge control device according to this embodiment. When solar charging is initiated by the solar power generation device 200, power control is performed in steps S1 to S7 unless the voltage of the battery 101 exceeds the overvoltage threshold. That is, charging is performed from the solar panel 201 to the battery 101 (step S2), and it is determined whether the voltage of the battery 101 exceeds the upper limit of the rated voltage (step S3). If the voltage of the battery 101 does not exceed the upper limit of the rated voltage in step S3, the process proceeds to step S2. On the other hand, if the voltage of the battery 101 exceeds the upper limit of the rated voltage in step S3, the solar panel 201 with the largest power generation capacity is stopped (step S4). Next, it is determined whether the voltage of the battery 101 has fallen below the target voltage (step S5). If the voltage of the battery 101 has not fallen below the target voltage, step S5 is repeated. On the other hand, if the voltage value of the battery 101 falls below the target voltage value, the stopped solar panel 201 is restarted (step S6). On the other hand, if the voltage value of the battery 101 exceeds the overvoltage threshold, solar charging is interrupted.

[0069] FIG. 4 is a waveform diagram showing voltage changes during the operation shown in the flowchart of FIG. 3 . Here, as an example, two solar panels 201 are used. In the vehicle 100, the time during which the onboard alternator 103 generates electricity is minimized. For example, if the onboard alternator 103 operates when the voltage value of the battery 101 is 28.3 V, the onboard alternator 103 stops generating electricity when the voltage value of the battery 101 reaches 28.5 V or higher. This reduces the load on the internal combustion engine (engine), improving fuel efficiency. On the other hand, when the voltage value of the battery 101 falls to 27.8 V or lower, the onboard alternator 103 operates and resumes generating electricity. This increases the load on the internal combustion engine, resulting in poor fuel efficiency.

[0070] Meanwhile, in the charge control device 203 of the solar panel 201, the target voltage value of the battery 101 is 28.8 V, and the charging overvoltage of the battery 101 is 32 V. When the voltage value of the battery 101 drops to 28.5 V, recharging by the solar panel 201 is initiated. When the overcharge prevention voltage of 29 V or higher is detected for 50 ms or more, one of the solar panels 201 is stopped, and when the voltage value of the battery 101 drops to 28.5 V, recharging is initiated by both solar panels 201. Even if the voltage of the battery 101 momentarily rises due to an I-V scan, fluctuations in power generation, or the like, a detection that the voltage value of the battery 101 has risen to 29 V or higher is ignored (passed through) within a period of 50 ms.

[0071] The functions of the control unit 205, the measurement unit 207, and the switch unit 209 in the charging control device 203 can also be realized by a processor executing a program stored in a non-volatile memory (not shown). That is, the functions of the control unit 205, the measurement unit 207, and the switch unit 209 can be realized by software, firmware, or a combination of software and firmware. The software or firmware is written as a program and stored in a memory (not shown). The processor realizes the function of each unit by reading and executing the program stored in the memory. The program causes a computer to execute the procedures or methods of the control unit 205, the measurement unit 207, and the switch unit 209.

[0072] [Second Embodiment] In the first embodiment, after solar charging starts, if the voltage value of the battery 101 exceeds the upper limit of the rated voltage, power generation by some of the solar panels 201 is stopped, and if the voltage value of the battery 101 subsequently falls below a target voltage value, the stopped solar panels 201 are restarted. In the second embodiment, if the voltage value of the battery 101 is within a predetermined range between the upper limit voltage value at which charging to the battery 101 is permitted and a predetermined voltage value of the battery 101 at which the on-board alternator 103 starts charging the battery 101, a power ratio R supplied from the solar panels 201 to the battery 101 is adjusted based on the voltage value of the battery 101. Here, the power ratio R is the proportion of power supplied to the battery 101 out of the power output from the solar panels 201.

[0073] The predetermined range can be set as appropriate as long as it is within a range between an upper limit voltage value at which charging of the battery 101 is permitted and a predetermined voltage value of the battery 101 at which the on-board alternator 103 starts charging the battery 101. Therefore, the upper limit value of the predetermined range may be the upper limit voltage value at which charging of the battery 101 is permitted, and the lower limit value of the predetermined range may be a predetermined voltage value of the battery 101 at which the on-board alternator 103 starts charging the battery 101. Furthermore, the upper limit value of the predetermined range may be an upper limit value of the rated voltage of the battery 101 or a value that is predetermined as an upper threshold value lower than the upper limit value. Furthermore, the lower limit value of the predetermined range may be a voltage value of the battery 101 at which the on-board alternator 103 starts charging the battery 101 or a lower threshold value higher than that voltage value.

[0074] When the voltage value of the battery 101 is within the predetermined range, the power ratio R is adjusted so that the power ratio R decreases as the voltage value increases. Specifically, in the second embodiment, the power ratio R is 100% when the voltage value of the battery 101 is smaller than the lower limit of the predetermined range (e.g., 28.5 V), and is 0% when the voltage value of the battery 101 exceeds the upper limit of the predetermined range (e.g., 29.0 V). When the voltage value of the battery 101 is within the predetermined range (e.g., 28.5 V or more and 29.0 V or less), the power ratio R is adjusted so that the power ratio R decreases as the voltage value increases (i.e., the power ratio R increases as the voltage value decreases).

[0075] By adjusting the power ratio R in this manner, even if the voltage value of the battery 101 rises when the voltage value is within a predetermined range, the power ratio R is reduced, and the power charged to the battery 101 is reduced. By reducing the power charged to the battery 101, the rise in the voltage value is suppressed, and it is possible to prevent or suppress the voltage value from exceeding the upper limit of the predetermined range. Furthermore, even if the voltage value of the battery 101 falls when the voltage value is within the predetermined range, the power ratio R is increased, and the power charged to the battery 101 is increased. By increasing the power charged to the battery 101, the drop in the voltage value is suppressed, and it is possible to prevent or suppress the voltage value from falling below the lower limit of the predetermined range.

[0076] 5 is a flowchart illustrating the operation of the charge control device according to the second embodiment. When the solar power generation device 200 starts solar power generation, the control unit 205 acquires the power P output from the solar power generation device (step S11) and determines whether the power P is 10 W or more (step S12). If the power P is less than 10 W, the process of step S11 is repeated. If the power P is 10 W or more, an IV scan is performed to search for the maximum power point MP (step S13). If the maximum power point MP is not detected by the IV scan (step S14: No), the IV scan is repeated. If the maximum power point MP is detected by the IV scan (step S14: Yes), a loop process is executed (step S15).

[0077] In the loop process, the following steps S16 to S22 are repeatedly performed. In step S16, the voltage value D of the battery 101 is acquired. In step S17, it is determined whether the acquired voltage value D is less than 28.5 V, which is set as the lower limit of a predetermined range. If the voltage value D is less than 28.5 V (step S17: Yes), the power ratio R is set to 100% (step S19). On the other hand, if the voltage value D is 28.5 V or more (step S17: No), it is determined whether the voltage value D is less than 29.0 V, which is set as the upper limit of the predetermined range (step S18). If the voltage value D is higher than 29.0 V (step S18: No), the power ratio R is set to 0% (step S21). On the other hand, if the voltage value D is 29.0 V or less (step S18: Yes), that is, if the voltage value D is equal to or greater than the lower limit (28.5 V) and equal to or less than the upper limit (29.0 V), the process proceeds to step S20.

[0078] In step S20, the power ratio R is calculated by the following formula (1): R=(29.0-D)×200(%) (1)

[0079] According to the above formula (1), the power ratio R is calculated so that the power ratio R decreases as the voltage value D increases within the range of 28.5 V to 29.0 V. For example, when the voltage value D is 28.6 V, the power ratio R is 80%, when the voltage value D is 28.7 V, the power ratio R is 60%, when the voltage value D is 28.8 V, the power ratio R is 40%, and when the voltage value D is 28.9 V, the power ratio R is 20%.

[0080] After the power ratio R is set in steps S19, S20, and S21, power control is performed based on the set power ratio R (S22). In this power control, if the power ratio R is set to 100% in step S19, all of the power generated by the solar panel 201 is supplied to (charges) the battery 101. If the power ratio R is set to 0% in step S21, no power generated by the solar panel 201 is supplied to the battery 101. If the power ratio R is calculated using the above formula (1) in step S20, power corresponding to the calculated power ratio R is supplied to the battery 101. For example, if the power ratio R is 80%, 80% of the power generated by the solar panel 201 is supplied to the battery 101, and if the power ratio is 60%, 60% of the power generated by the solar panel 201 is supplied to the battery 101.

[0081] In the power control in step S22, the power generated by the solar panel 201 that is not supplied to the battery 101 (hereinafter referred to as surplus power) can be discarded. Also, the surplus power can be converted into other energy (such as heat).

[0082] The power control in step S22 can be executed, for example, as follows. If the power generated by the solar panel 201 is, for example, 10 W, and the voltage is set to 10 V by MPPT control, then if the power ratio R is 100%, the current is adjusted so that 1 A flows to the battery 101. Also, if the power ratio R is 50%, the current is adjusted so that 0.5 A flows to the battery 101. If the power ratio R is 0%, no current is allowed to flow to the battery 101. Also, the amount of power generated by the solar panel 201 can be automatically controlled by MPPT control so that surplus power is not generated.

[0083] After the power control is executed in step S22, the process returns to step S15, and the loop process is repeated. If a predetermined control termination condition is met during the loop process (for example, if the power generated by the solar panel 201 falls below 10 W), the solar power generation is stopped.

[0084] 6 is a diagram showing, in waveform, an example of changes in the battery voltage value D [V] and changes in the power (supplied power) P [W] supplied from the solar panel 201 to the battery 101 in the operation shown in the flowchart of FIG. 5. In FIG. 6, an IV scan is executed during a period T0 to determine the maximum output point. After the period T0, a loop process is executed to perform output control. During output control, the voltage value D of the battery 101 is sampled every short time (for example, every 1 ms). Hereinafter, the sampled voltage value will be referred to as the sampled voltage value D.

[0085] 6, the sampled voltage value D at time ta immediately after the start of output control is less than 28.5 V, so the power ratio R is set to 100% in the next sampling period (1 ms). Furthermore, the sampled voltage value D at time tb after time ta reaches 28.5 V, and thereafter the sampled voltage value D remains at or above 28.5 V.

[0086] The sampled voltage value D rises gradually from time tb to time tc, then rises sharply from time tc to time td, then rises gradually from time td to time te, and then rises sharply again from time te to time tf. During these periods, the sampled voltage value D continues to rise within the range of 28.5 V to 29.0 V, so the power ratio R decreases with a delay of one sampling period (1 ms) and continues to decrease thereafter. Because the power ratio R decreases gradually during the period corresponding to the period in which the sampled voltage value D is gradually rising, the supplied power P also decreases gradually. Because the power ratio R decreases sharply during the period in which the sampled voltage value D is rapidly rising, the supplied power P also decreases sharply. Furthermore, because the sampled voltage value D reaches 29.0 V at time tf, the power ratio R is set to 0% at the time of the next sampling period. As a result, the supplied power P becomes 0 at time tf.

[0087] Between time tf and time tg, the sampled voltage value D gradually decreases, and between time tg and time th, the sampled voltage value D rapidly decreases. During these periods, the sampled voltage value D continues to decrease within the range of 28.5 V to 29.0 V, so the power ratio R increases with a delay of the sampling period (1 ms) and continues to increase thereafter. Furthermore, since the power ratio R gradually increases during the period corresponding to the period when the sampled voltage value D is gradually decreasing, the supplied power P also gradually increases. Since the power ratio R rapidly decreases during the period corresponding to the period when the sampled voltage value D is rapidly decreasing, the supplied power P also rapidly increases.

[0088] As described above, according to the second embodiment, when the voltage value of battery 101 is within a predetermined range between the upper limit voltage value at which charging of battery 101 is permitted and the predetermined voltage value of battery 101 at which on-board alternator 103 starts charging battery 101, the power ratio R supplied from solar panel 201 to battery 101 is adjusted based on the voltage value of battery 101 (sampled voltage value D). This prevents the voltage value D of battery 101 from becoming higher than the upper limit voltage value, causing deterioration of battery 101, and prevents the voltage value D of battery 101 from becoming lower than the voltage value at which on-board alternator 103 starts charging battery 101, causing on-board alternator 103 to operate and resulting in a decrease in fuel economy.

[0089] 6, in particular, when the sampled voltage value D rises sharply, the power ratio R drops sharply, and therefore the supplied power P also drops sharply. Therefore, even if, for example, a sudden drop in the power load causes the supplied power P to exceed the consumed power, resulting in a sudden rise in the sampled voltage value D, the supplied power P drops sharply in response to the sudden rise in the sampled voltage value D. Therefore, only power commensurate with the drop in the power load is supplied to the battery 101, and no excessive power is supplied to the battery 101. This makes it possible to effectively prevent overcharging of the battery 101 due to excessive power being supplied to the battery 101, and deterioration of the battery 101 that accompanies overcharging.

[0090] 6, when the sampled voltage value D suddenly drops, the power ratio R suddenly rises, and so the supply power P also suddenly rises. Therefore, even if, for example, a sudden rise in the power load causes the power consumption to exceed the supply power P, causing the sampled voltage value D to suddenly drop, the supply power P suddenly rises in response to the sudden drop in the sampled voltage value D, so that sufficient power commensurate with the increase in the power load is supplied to the battery 101. This makes it possible to effectively prevent the voltage value D of the battery 101 from dropping significantly due to a sudden rise in the power load, causing the on-board alternator 103 to operate.

[0091] In the second embodiment described above, an example was shown in which the power ratio R was adjusted so that the power ratio R varied between 0% and 100% when the voltage value of the battery 101 was within a predetermined range. However, the adjustment range of the power ratio R is not limited to this and can be set to various ranges. For example, the power ratio R can be adjusted so that the power ratio R varied between 20% and 80%. Furthermore, the control described in the second embodiment and the control described in the first embodiment can be combined. For example, the control described in the second embodiment may be performed when the voltage value of the battery 101 is within a predetermined range between the upper limit voltage value at which charging of the battery 101 is permitted and the voltage value at which the on-board alternator 103 starts charging the battery 101, and the control described in the first embodiment may be performed when the voltage value of the battery 101 deviates from the predetermined range.

[0092] As described above, the charge control device and the charge control program according to this embodiment can reduce power generation by the generator, thereby improving fuel efficiency, contributing to the solution of the social issue of carbon neutrality, and preventing battery deterioration. Furthermore, by extending the period during which the generator is not generating power, the life of the generator itself can be extended.

[0093] REFERENCE SIGNS LIST 100 Vehicle 101 Battery 103 On-vehicle alternator 200 Photovoltaic power generation device 201 Solar panel 203 Charging control device 205 Control unit 207 Measuring unit 209 Switch unit

Claims

1. In a moving body provided with a battery that stores electric power supplied from at least one of a generator that converts mechanical energy into electric energy and a solar panel that generates electric power using sunlight, a charging control device that controls the solar panel, comprising: a measurement unit that measures the voltage of the battery; and a control unit that controls the supply of electric power from the solar panel to the battery such that the measured voltage value of the battery becomes a voltage value between an upper limit voltage value at which charging of the battery is permitted and a voltage value of the battery at which the generator starts charging the battery as predetermined. A charging control device characterized by comprising the above.

2. The control unit stops the supply of electric power from the solar panel to the battery when the voltage value of the battery exceeds an upper limit threshold that is lower than the upper limit voltage value at which charging of the battery is permitted, while the control unit supplies electric power from the solar panel to the battery when the voltage value of the battery falls below a lower limit threshold that is higher than the voltage value of the battery at which the generator starts charging the battery as predetermined. The charging control device according to claim 1, characterized by comprising a switch unit or a function of determining ON / OFF of the supply.

3. The measurement unit measures the voltage of the battery in a state where the supply of electric power from the solar panel to the battery is not performed when the moving body starts, and the control unit sets the measured voltage value as the voltage value of the battery at which the generator starts charging the battery. The charging control device according to claim 2, characterized by the above.

4. The control unit supplies electric power from the solar panel to the battery by maximum power point tracking control (Maximum Power Point Tracking). The charging control device according to claim 1, characterized by the above.

5. When the voltage value of the battery is within a predetermined range between the upper limit voltage value and the voltage value of the battery at which the generator starts charging the battery as predetermined, the control unit adjusts the power ratio supplied from the solar panel to the battery based on the voltage value of the battery. The charging control device according to claim 4, characterized by the above.

6. When the voltage value of the battery is within the predetermined range, the control unit adjusts the power supplied from the solar panel to the battery such that the higher the voltage value of the battery, the lower the power ratio. The charging control device according to claim 5, characterized in that.

7. A device that controls a plurality of solar panels, wherein the control unit selects a solar panel having the maximum instantaneous maximum power or a combination of solar panels having the maximum instantaneous maximum power, and controls the power supply to the battery. The charging control device according to claim 1, characterized in that.

8. The charging control device according to any one of claims 1 to 7, characterized in that the power supply from the solar panel to the battery is stopped or decreased while the moving body is decelerating or in a self-powered operation.

9. The control unit acquires information indicating the state of the moving body from a network mounted on the moving body, and controls the power supply from the solar panel to the battery based on the acquired information. The charging control device according to any one of claims 1 to 7, characterized in that.

10. The charging control device according to claim 9, characterized in that the control unit controls the power supply from the solar panel to the battery based on the information indicating the state of the generator acquired from the network.

11. The control unit calculates the voltage of the battery based on the voltage of the battery when there is no power supply from the solar panel to the battery, the voltage of the battery when there is power supply from the solar panel to the battery, and the current from the battery. The charging control device according to claim 1, characterized in that.

12. The charging control device according to any one of claims 1 to 7, characterized in that the control unit controls the power supply from the solar panel to the battery in a state where the moving body is not operating.

13. The charging control device according to claim 1, characterized in that when the voltage value of the battery exceeds the upper limit value of the rated voltage of the battery, the power supply from the solar panel to the battery is stopped.

14. A charging control program for controlling a moving object provided with a battery that stores power supplied from at least one of a generator that converts mechanical energy into electrical energy or a solar panel that generates power using sunlight, the program causing a computer to execute: a process of measuring the voltage of the battery; and a process of controlling the power supply from the solar panel to the battery so that the measured voltage value of the battery is a voltage value between an upper limit voltage value at which charging of the battery is permitted and a voltage value of the battery at which the generator starts charging the battery, which is predetermined. A charging control program characterized by the above.

15. The charging control program according to claim 14, further including a process of stopping the power supply from the solar panel to the battery when the voltage value of the battery exceeds an upper limit threshold value that is lower than the upper limit voltage value at which charging of the battery is permitted, and a process of supplying power from the solar panel to the battery when the voltage value of the battery falls below a lower limit threshold value that is higher than the voltage value of the battery at which the generator starts charging the battery, which is predetermined.

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