JP2021087291A - Solar charging system - Google Patents

Abstract

To provide a solar charging system that can improve the charging efficiency of the entire system while suppressing the generation of an intermediate voltage that cannot charge a battery.SOLUTION: A solar charging system includes a solar panel, a non-isolated DCDC converter (DDC) that uses output power of the solar panel as an input, an insulated DDC that uses output power of the non-insulated DDC as an input, a battery that has a minimum voltage set higher than a maximum output voltage of the solar panel and is supplied with the output power of the isolated DDC, a capacitor connected between the non-insulated DDC and the insulated DDC, and a control unit that controls the non-insulated DDC and the insulated DDC, and the control unit that controls the non-insulated DDC such that the voltage of the capacitor is a first voltage higher than the input voltage of the isolated DDC that maximizes the boost ratio of the insulated DDC, which is determined on the basis of the voltage of the battery when the power generated by the solar panel is supplied to the battery.SELECTED DRAWING: Figure 1

Description

The present invention relates to a solar charging system that controls charging of a battery using the generated power of a solar panel.

Patent Document 1 discloses a solar charging system in which the electric power generated by a solar panel is temporarily stored in a solar battery, and when a certain amount of electric power is stored, the electric power is supplied from the solar battery to an auxiliary battery or the like. .. In the solar charging system described in Patent Document 1, even when the current consumption under the auxiliary equipment load is large, the charging efficiency is improved by preventing the auxiliary equipment output from decreasing.

Japanese Unexamined Patent Publication No. 2015-116067

In order to reduce the system cost, it is conceivable to replace the solar battery with an inexpensive large-capacity capacitor capable of temporarily storing electricity. However, since the amount of charge lost by self-discharge of a capacitor is larger than that of a battery, the potential of a capacitor becomes zero immediately if it is not charged for a long period of time. Therefore, before supplying power from the solar panel to the battery, the capacitor is precharged to an intermediate voltage that takes a value between the solar panel voltage and the battery voltage to prevent the generation of inrush current from the solar panel to the capacitor. doing.

However, in the control of the intermediate voltage for precharging the capacitor, the involvement in charging efficiency is dominant, and when the isolated DCDC converter that boosts the intermediate voltage to the battery voltage operates or stops operating with low efficiency. , The charging efficiency of the entire solar charging system may decrease.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a solar charging system capable of increasing the charging efficiency of the entire system while suppressing the generation of an intermediate voltage that cannot be charged by a battery. And.

In order to solve the above problems, one aspect of the present invention is a solar panel, a non-isolated DCDC converter that receives the output power of the solar panel as an input, and an insulation that receives the output power of the non-isolated DCDC converter as an input. A type DCDC converter, a battery in which the minimum voltage is set higher than the maximum output voltage of the solar panel and the output power of the isolated type DCDC converter is supplied, and a non-isolated DCDC converter and an isolated type DCDC converter. A capacitor connected to the battery and a control unit for controlling a non-isolated DCDC converter and an isolated DCDC converter are provided, and the control unit supplies power generated by the solar panel to the battery. A non-isolated DCDC converter so that the voltage of the capacitor is the first voltage higher than the input voltage of the isolated DCDC converter that maximizes the boost ratio of the isolated DCDC converter, which is determined based on the battery voltage. It is a controlled solar charging system.

According to the solar charging system of the present invention, it is possible to improve the charging efficiency of the entire system while suppressing the generation of an intermediate voltage that cannot be charged by the battery.

Schematic configuration diagram of the solar charging system according to this embodiment Correspondence diagram of input / output voltage that the high voltage DCDC converter has the maximum efficiency Flow chart of charge control executed by the solar charge control device An example of the maximum efficiency point map of a high-voltage DCDC converter Diagram explaining the setting method of the maximum efficiency point map The figure explaining the setting method of the intermediate voltage in the auxiliary battery power supply mode. Schematic configuration of the solar charging system of the application example

[Embodiment]
Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

<Structure>
FIG. 1 is a block diagram showing a schematic configuration of a solar charging system according to an embodiment of the present invention. The solar charging system 1 illustrated in FIG. 1 includes a solar panel 10, a solar charging control device 20, a high-voltage battery 30, and an auxiliary battery 40. This solar charging system 1 can be mounted on a vehicle or the like.

The solar panel 10 is a power generation device that generates electricity by being irradiated with sunlight, and is typically a solar cell module that is an aggregate of solar cell cells. The amount of electric power generated by the solar panel 10 depends on the intensity of solar radiation. The electric power generated by the solar panel 10 is output to the solar charge control device 20. The solar panel 10 can be installed on, for example, the roof of a vehicle.

The high-voltage battery 30 is a rechargeable secondary battery such as a lithium-ion battery or a nickel-metal hydride battery. The high-voltage battery 30 is connected to the solar charge control device 20 so that it can be charged by the electric power generated by the solar panel 10. Typically, the high voltage battery 30 is set to have a minimum voltage (eg 360V) higher than the maximum output voltage (eg 55V) of the solar panel 10. The high-voltage battery 30 mounted on the vehicle is for so-called driving, which can supply electric power necessary for the operation of main equipment (not shown) for driving the vehicle, such as a starter motor and an electric motor. A battery can be exemplified.

The auxiliary battery 40 is a rechargeable secondary battery such as a lithium ion battery or a lead storage battery. The auxiliary battery 40 is connected to the solar charge control device 20 so that it can be charged by the electric power generated by the solar panel 10. The auxiliary battery 40 mounted on the vehicle is an auxiliary device other than for driving the vehicle, such as lights such as headlamps and interior lights, air conditioners such as heaters and coolers, and devices for automatic driving and advanced driving support. It is a so-called 12V system battery that can supply the power required for the operation of a typical device (not shown).

The solar charge control device 20 is a connection portion that connects the solar panel 10, the high-pressure battery 30, and the auxiliary battery 40, and can supply the electric power generated by the solar panel 10 to the high-pressure battery 30 and the auxiliary battery 40. It is an electronic control device (ECU) that can be used. This electronic control unit (ECU) is typically configured to include a processor, a memory, an input / output interface, and the like, and the processor reads and executes a program stored in the memory to perform various controls. .. The solar charge control device 20 according to the present embodiment includes a solar DCDC converter 21, a high-voltage DCDC converter 22, an auxiliary DCDC converter 23, a control unit 25, and a capacitor 26 in its configuration.

The solar DCDC converter 21 supplies the electric power generated by the solar panel 10 to the high-voltage DCDC converter 22 and the auxiliary DCDC converter 23. At the time of power supply, the solar DCDC converter 21 converts (boost / step down) the generated voltage of the solar panel 10, which is an input voltage, into a predetermined voltage based on an instruction from the control unit 25 described later, and the high-voltage DCDC converter 22 And it can be output to the auxiliary DCDC converter 23. The solar DCDC converter 21 can be a non-insulated step-up / step-down DCDC converter in which the primary side and the secondary side are not insulated.

The high-voltage DCDC converter 22 supplies the electric power output from the solar DCDC converter 21 to the high-voltage battery 30. At the time of power supply, the high-voltage DCDC converter 22 converts (boosts) the output voltage of the solar DCDC converter 21, which is an input voltage, into a predetermined voltage based on an instruction from the control unit 25 described later, and outputs the output to the high-voltage battery 30. can do. The high-voltage DCDC converter 22 can be an isolated type step-up DCDC converter in which the primary side and the secondary side are insulated by a transformer. An isolated step-up DCDC converter using a transformer has a step-up ratio (primary voltage) that maximizes efficiency depending on the transformer turn ratio (ratio of the number of turns of the primary coil to the number of turns of the secondary coil). And the ratio of the secondary voltage) is determined. Specifically, when the step-up ratio is matched with the turns ratio of the transformer, the efficiency of the isolated step-up DCDC converter is maximized. FIG. 2 shows an example of the correspondence between the primary side voltage (input voltage) and the secondary side voltage (output voltage) at which the isolated type boosted DCDC converter has the maximum efficiency.

The auxiliary DCDC converter 23 supplies the electric power output from the solar DCDC converter 21 to the auxiliary battery 40. At the time of power supply, the auxiliary DCDC converter 23 converts (lowers) the output voltage of the solar DCDC converter 21, which is an input voltage, into a predetermined voltage based on an instruction from the control unit 25 described later, and the auxiliary battery 40. Can be output to. The auxiliary DCDC converter 23 can be a non-insulated step-down DCDC converter in which the primary side and the secondary side are not insulated.

The control unit 25 is composed of, for example, a microcomputer, and is a solar DCDC converter 21 and a high-voltage DCDC converter 22 based on the electric power (voltage, current) generated by the solar panel 10 and the running state of the vehicle acquired from an in-vehicle device (not shown). , And the auxiliary DCDC converter 23 are instructed to control the operation.

When the power generated by the solar panel 10 is supplied to the high-pressure battery 30 and the auxiliary battery 40, the capacitor 26 determines the potential difference between the generated voltage of the solar panel 10 and the stored voltage of the high-pressure battery 30 or the stored voltage of the auxiliary battery 40. It is a capacitive element for holding an intermediate voltage Vmid for the purpose of keeping it small. The capacitor 26 is inserted between the wiring connecting the solar DCDC converter 21, the high-voltage DCDC converter 22, and the auxiliary DCDC converter 23, and the ground potential.

<Control>
Next, the control performed by the solar charging system 1 will be described with reference to FIG. FIG. 3 is a flowchart illustrating a charging control processing procedure executed by the solar charging control device 20 of the solar charging system 1 according to the present embodiment.

The charge control shown in FIG. 3 is started when the solar panel 10 is sufficiently generating power so that the high-voltage battery 30 and the auxiliary battery 40 can be efficiently charged. Whether or not the solar panel 10 is sufficiently generating power is that the generated power (voltage, current) of the solar panel 10 is equal to or higher than the threshold value set for efficient charging of the high-pressure battery 30 and the auxiliary battery 40. It can be judged by whether or not.

Step S301: The solar charge control device 20 determines whether the vehicle is in a running state or a state other than that. This determination is made to determine the power supply destination of the generated power of the solar panel 10. If the vehicle is in a running state (step S301, yes), the process proceeds to step S303, and if the vehicle is in a state other than running (step S301, no), the process proceeds to step S302.

Step S302: The solar charge control device 20 sets the power supply mode of the solar charging system 1 to the “high pressure battery power supply mode” in which the power generated by the solar panel 10 is supplied to the high pressure battery 30 and the auxiliary battery 40 in parallel. In this high-voltage battery power supply mode, the solar DCDC converter 21, the high-voltage DCDC converter 22, and the auxiliary DCDC converter 23 all perform predetermined step-up or step-down operations according to the instructions of the control unit 25. In the high-voltage battery power supply mode, power obtained by subtracting the amount of power supplied to the auxiliary DCDC converter 23 from the output power of the solar DCDC converter 21 is supplied to the high-voltage battery 30. When the power supply mode is set, the process proceeds to step S304.

Step S303: The solar charge control device 20 sets the power supply mode of the solar charging system 1 to the “auxiliary battery power supply mode” in which the power generated by the solar panel 10 is supplied only to the auxiliary battery 40. In this auxiliary battery power supply mode, the solar DCDC converter 21 and the auxiliary DCDC converter 23 each perform predetermined operations according to the instructions of the control unit 25, and the high-voltage DCDC converter 22 stops operating. When the power supply mode is set, the process proceeds to step S307.

Step S304: The solar charge control device 20 acquires the voltage Vhigh of the high voltage battery 30. The high-voltage battery 30 has a predetermined operating voltage range (for example, 350V to 460V), and the voltage Vhigh fluctuates according to the charge rate (SOC). When the voltage Vhigh of the high-voltage battery 30 is acquired, the process proceeds to step S305.

Step S305: The solar charge control device 20 extracts the first voltage V1 corresponding to the voltage Vhigh of the high voltage battery 30 with reference to the maximum efficiency point map illustrated in FIG. For example, when the voltage Vhigh of the high voltage battery 30 is 390V, 24.2V is extracted as the first voltage V1. As illustrated in FIG. 5, this maximum efficiency point map is determined based on the maximum efficiency (FIG. 2) of the isolated step-up DCDC converter, and the primary side voltage is increased by the offset from the maximum efficiency (solid line). It is a map in which the made voltage is set as the first voltage V1. The offset is a predetermined value determined based on the control performance of the solar DCDC converter 21 and the like. When the first voltage V1 corresponding to the voltage Vhigh of the high-voltage battery 30 is extracted, the process proceeds to step S306.

Step S306: The solar charge control device 20 sets the extracted first voltage V1 to the intermediate voltage Vmid. By setting the first voltage V1 to the intermediate voltage Vmid in this way, it is possible to give the intermediate voltage Vmid a control margin by an offset amount. That is, since the intermediate voltage Vmid is lowered due to the control fluctuation of the solar DCDC converter 21, the intermediate voltage Vmid can be raised to the voltage Vhigh of the high voltage battery 30 even with the maximum boost ratio of the high voltage DCDC converter 22. Therefore, it is possible to suppress the occurrence of an event such as the high voltage battery 30 cannot be charged. When the first voltage V1 is set to the intermediate voltage Vmid, the process proceeds to step S308.

Step S307: The solar charge control device 20 sets the second voltage V2 to the intermediate voltage Vmid. The second voltage V2 is a predetermined value determined based on the efficiency of the solar DCDC converter 21 and the efficiency of the auxiliary DCDC converter 23. In the example of FIG. 6, the voltage = 24V at the point where the efficiency curve of the solar DCDC converter 21 (solar DDC) and the efficiency curve of the auxiliary DCDC converter 23 (auxiliary DDC) intersect can be set as the second voltage V2. .. In this way, by setting the voltage at the point where the efficiency curves of the DCDC converters intersect with each other to the second voltage V2, that is, the intermediate voltage Vmid, it is possible to suppress that only a specific DCDC converter generates heat, and the solar charge control device. The heat generation source on No. 20 can be dispersed to eliminate hot spots. Therefore, the thermal design of the solar charge control device 20 becomes easy.

Step S308: The solar charge control device 20 determines the solar radiation for the solar panel 10. This solar radiation determination is performed to determine whether or not the solar panel 10 is generating sufficient power so that the high-voltage battery 30 and the auxiliary battery 40 can be efficiently charged. It is conceivable that the solar panel 10 affected by solar radiation may not be able to stably supply electric power capable of efficiently charging the high-voltage battery 30 and the auxiliary battery 40. If insufficient power is supplied to the high-voltage battery 30, efficient charging may not be possible. If the solar panel 10 is sufficiently generating solar radiation determination "OK", the process proceeds to step S310, and if the solar panel 10 is not sufficiently generating electricity, the solar radiation determination is "NG". Is finished.

Step S309: The solar charge control device 20 determines the solar radiation for the solar panel 10. The solar radiation determination in step S309 is the same as the solar radiation determination in step S308. If the solar panel 10 is sufficiently generating solar radiation determination "OK", the process proceeds to step S311, and if the solar panel 10 is not sufficiently generating electricity, the solar radiation determination is "NG". Is finished.

Step S310: The solar charge control device 20 determines whether the vehicle is in a running state or a state other than that. This determination is made in order to determine again the power supply destination of the generated power of the solar panel 10. When the vehicle is in the running state (step S310, yes), the process proceeds to step S303, and the power supply mode of the solar charging system 1 shifts from the high voltage battery power supply mode to the auxiliary battery power supply mode. On the other hand, when the vehicle is in a state other than running (step S310, no), the process proceeds to step S304, and the high-voltage battery power supply mode is continued as the power supply mode of the solar charging system 1.

Step S311: The solar charge control device 20 determines whether the vehicle is in a running state or a state other than that. This determination is made in order to determine again the power supply destination of the generated power of the solar panel 10. If the vehicle is in a running state (step S311, yes), the process proceeds to step S309, and the auxiliary battery power supply mode is continued as the power supply mode of the solar charging system 1. On the other hand, when the vehicle is in a state other than running (step S311, no), the process proceeds to step S302, and the power supply mode of the solar charging system 1 shifts from the auxiliary battery power supply mode to the high voltage battery power supply mode.

<Application example>
The case where the solar charging system 1 of the above embodiment controls the charging of the high voltage battery 30 and the auxiliary battery 40 based on the electric power generated by one solar panel 10 has been described. However, the number of solar panels 10 may be two or more.

FIG. 7 shows a schematic configuration of the solar charging system 2 of the application example. The solar charging system 2 includes two solar panels 10a (for example, the front side of the vehicle) and a solar panel 10b (for example, the rear side of the vehicle). The solar charge control device 27 is provided with a solar DCDC converter 21a for the solar panel 10a and a solar DCDC converter 21b for the solar panel 10b. The solar charge control device 27 controls charging of the high-voltage battery 30 and the auxiliary battery 40 based on the total amount of electric power generated by each of the solar panels 10a and 10b.

<Action / effect>
As described above, according to the solar charging system according to the embodiment of the present invention, in the high-voltage battery power supply mode, the solar charging control device is a high-voltage DCDC converter which is an isolated DCDC converter whose involvement in charging efficiency is dominant. Based on the voltage of the high-voltage battery charged by the output of the converter, the intermediate voltage of the capacitor is dynamically controlled so that the high-voltage DCDC converter operates with high efficiency.

By this control, the solar charge control device can suppress the operation of the high-voltage DCDC converter with low efficiency, and can increase the charge efficiency of the entire solar charging system. Further, since the intermediate voltage is controlled by providing a control margin by the offset voltage, the solar charging control device can suppress the operation of the high-voltage DCDC converter from stopping, and further enhance the charging efficiency of the entire solar charging system. Can be done.

Although one embodiment of the present invention has been described above, the present invention describes not only the solar charging system but also the charging control method performed by the solar charging system, the control program of the charging control method, and the computer readable that stores the control program. It can be regarded as a non-temporary storage medium, a solar charging system including a solar charging system, a vehicle equipped with the solar charging system, and the like.

The present invention can be used for a vehicle or the like that charges a battery by using the electric power generated by the solar panel.

1, 2 Solar charging system 10, 10a, 10b Solar panel 20, 27 Solar charging controller 21, 21a, 21b Solar DCDC converter 22 High-voltage DCDC converter 23 Auxiliary DCDC converter 25 Control unit 26 Capacitor 30 High-pressure battery 40 Auxiliary battery

Claims (1)

With solar panels
A non-isolated DCDC converter that uses the output power of the solar panel as an input,
An isolated DCDC converter that receives the output power of the non-isolated DCDC converter as an input, and
A battery in which the minimum voltage is set higher than the maximum output voltage of the solar panel and the output power of the isolated DCDC converter is supplied, and
A capacitor connected between the non-isolated DCDC converter and the isolated DCDC converter,
A control unit for controlling the non-isolated DCDC converter and the isolated DCDC converter is provided.
When the control unit supplies power generated by the solar panel to the battery, the insulation that maximizes the boost ratio of the isolated DCDC converter in which the voltage of the capacitor is determined based on the voltage of the battery. The non-isolated DCDC converter is controlled so that the first voltage is higher than the input voltage of the DCDC converter of the type.
Solar charging system.

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