JP2014018019A - Solar charge system and mobile body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a solar charge system capable of implementing high efficiency.SOLUTION: A solar charge system comprises: a solar cell; an MPPT for controlling an operating point of the solar cell in order to maximize generation power of the solar cell; first and second power storage devices; a plurality of both-way DC-DC converters for transmitting power between the first and second power storage devices; and a control unit for controlling the number of operating ones of the plurality of both-way DC-DC converters. An output end of the solar cell is connected to an input end of the MPPT; and an output end of the MPPT is connected to the first power storage device. Each first input/output terminal of the plurality of both-way DC-DC converters is connected to the first power storage device; and each second input/output terminal of the plurality of both-way DC-DC converters is connected to the second power storage device.

Description

  The present invention relates to a solar charging system that charges a power storage device using generated electric power of a solar cell and a mobile body including the solar charging system.

  Conventionally, it has been proposed to apply a solar charging system to automobiles such as EVs (Electric Vehicles), HVs (Hybrid Vehicles), and PHVs (Plug-in Hybrid Vehicles) having a motor drive mechanism.

  The cruising distance of automobiles having a motor drive mechanism has become a major issue, and a system that efficiently uses electricity has become indispensable.

  In the automobile disclosed in Patent Documents 1 to 3, the solar panel and the battery for driving the motor of the motor drive mechanism are directly connected (connected without passing through another battery). For solar panels for automobiles, power generation at 60V or less is desirable for safety measures.

JP 2007-228753 A Japanese Patent Laid-Open No. 5-111112 JP 2008-31382 A JP 2011-501013 (paragraph 0023, FIG. 1)

  However, in a configuration in which the solar panel and the battery for driving the motor of the motor drive mechanism are directly connected, if the solar panel generates power at 60 V or less, the battery for driving the motor of the motor drive mechanism Since the voltage cannot be made sufficiently high, a large current is caused to flow from the battery for driving the motor of the motor drive mechanism to the motor of the motor drive mechanism, resulting in a large efficiency reduction due to the large current.

  In Patent Document 4, a solar panel and a battery (high voltage battery) for driving the motor of the motor drive mechanism can be connected via another battery (vehicle battery). However, in Patent Document 4, when a power is transmitted from a solar panel to a vehicle battery to charge the vehicle battery, and when a high voltage battery is charged by transmitting power from the vehicle battery to the high voltage battery. The voltage converter used is the same, both when charging power from the solar panel to the vehicle battery and charging the vehicle battery and when charging power from the vehicle battery to the high voltage battery and charging the high voltage battery, There is a problem that the voltage conversion efficiency of the voltage converter cannot be increased.

  An object of this invention is to provide the solar charging system which can achieve high efficiency in view of said situation, and a mobile body provided with the same.

  In order to achieve the above object, a solar charging system according to the present invention includes a solar cell, MPPT (Maximum Power Point Tracking) for controlling the operating point of the solar cell in order to maximize the generated power of the solar cell, A first power storage device, a second power storage device, a plurality of bidirectional DC-DC converters for transmitting power between the first power storage device and the second power storage device, and the plurality of bidirectional DC-DC converters And a control unit for controlling the number of operation of the solar cell, wherein an output end of the solar cell is connected to an input end of the MPPT, an output end of the MPPT is connected to the first power storage device, and the plurality of bidirectional DC- Each first input / output terminal of the DC converter is connected to the first power storage device, and each second input / output terminal of the plurality of bidirectional DC-DC converters is connected to the second power storage device (first Configuration) The

  According to such a configuration, by charging the first power storage device with power, the power generated by the solar cell can be generated without operating the power storage device management unit that manages the second power storage device and controls the second power storage device. The first power storage device can be charged. In addition, the power of the first power storage device can be charged to the second power storage device by high-power transmission that does not depend on the generated power of the solar battery. Such two-stage charging enables high-efficiency electric power transmission regardless of the generated power of the solar cell, thereby achieving high efficiency. Furthermore, since the number of operations of the plurality of bidirectional DC-DC converters can be changed, the power of the second power storage device can be transmitted to the first power storage device with high efficiency.

  In the solar charging system having the first configuration, a configuration (second configuration) in which each of the plurality of bidirectional DC-DC converters is an insulated DC-DC converter is preferable.

  According to such a configuration, since the solar battery, the first power storage device, and the second power storage device can be insulated, safety is improved.

  Further, in the solar charging system of the first configuration or the second configuration, when the amount of power that can be output by the first power storage device is equal to or greater than a first predetermined value, the plurality of bidirectional DC-DC converters When at least one of the first power storage device transmits power from the first power storage device to the second power storage device to charge the second power storage device, and the amount of power that the first power storage device can output is equal to or less than a second predetermined value, At least one of the plurality of bidirectional DC-DC converters transmits power from the second power storage device to the first power storage device to charge the first power storage device, and the second predetermined value is the first predetermined value. A smaller configuration (third configuration) is preferable.

  According to such a configuration, when the amount of power that can be output by the first power storage device is large, power is transmitted from the first power storage device to the second power storage device, and the second power storage device is charged. When the amount of power that can be output decreases, power is transmitted from the second power storage device to the first power storage device and the first power storage device is charged, so only one of the first power storage device and the second power storage device is concentrated. And can be prevented from being charged. Thereby, overdischarge and overcharge of the first power storage device and the second power storage device can be prevented.

  In the solar charging system having the third configuration, when the amount of power that can be output from the first power storage device is equal to or less than a third predetermined value, power transmission from the first power storage device to the second power storage device is terminated. Then, charging of the second power storage device is terminated, and power transmission from the second power storage device to the first power storage device is terminated when the amount of power that can be output by the first power storage device exceeds a fourth predetermined value. Then, the charging of the first power storage device is terminated, the third predetermined value is smaller than the first predetermined value, the third predetermined value is larger than the fourth predetermined value, and the fourth predetermined value is A configuration larger than the second predetermined value (fourth configuration) is preferable.

  According to such a configuration, since the charging end condition of the first power storage device and the charging end condition of the second power storage device are defined, overdischarge and overcharge of the first power storage device and the second power storage device are more reliably performed. Can be prevented.

  In the solar charging system having any one of the first to fourth configurations, a configuration (fifth configuration) in which a plurality of types of power capacities of the plurality of bidirectional DC-DC converters are present is preferable.

  According to such a configuration, high-efficiency power transmission with a wide range of transmission power can be realized with a small number of bidirectional DC-DC converters.

  In the solar charging system having any one of the first to fifth configurations, the output terminal of the MPPT and the first input / output terminals of the plurality of bidirectional DC-DC converters are routed through the first power storage device. A configuration (sixth configuration) including a path to be connected without being preferable is preferable.

  According to such a configuration, when the power storage device management unit that manages the second power storage device and controls the second power storage device is inevitably operating, the generated power from the solar cell is supplied to the first power storage device. Since the second power storage device can be charged without going through, the charge / discharge loss of the first power storage device can be eliminated, and the efficiency can be further improved.

  In the solar charging system having any one of the first to sixth configurations, when both the SOC (state of charge) of the first power storage device and the SOC of the second power storage device become 100%, A configuration (seventh configuration) in which charging of the first power storage device or the second power storage device using generated power is terminated is preferable.

  According to such a configuration, overcharging of the first and second storage batteries can be prevented.

  In the solar charging system having any one of the first to seventh configurations, a configuration (eighth configuration) in which the voltage of the second power storage device is larger than the voltage of the first power storage device is preferable.

  According to such a configuration, since the voltage of the second power storage device can be increased, it is not necessary to flow a large current through the load connected to the second power storage device, resulting in a large efficiency reduction due to the large current. This can be prevented.

  Moreover, let the mobile body which concerns on this invention be a structure provided with the solar charging system of the structure in any one of the said 1st-8th.

  Moreover, in the mobile body having the above-described configuration, it is preferable that the power output from the second power storage device included in the solar charging system is used as power for driving the mobile body.

  According to the solar charging system and the moving body according to the present invention, by charging the first power storage device with power, without operating the power storage device management unit that manages the second power storage device and controls the second power storage device, The first power storage device can be charged with the power generated by the solar battery. In addition, the power of the first power storage device can be charged to the second power storage device by high-power transmission that does not depend on the generated power of the solar battery. Such two-stage charging enables high-efficiency electric power transmission regardless of the generated power of the solar cell, thereby achieving high efficiency. Furthermore, since the number of operations of the plurality of bidirectional DC-DC converters can be changed, the power of the second power storage device can be transmitted to the first power storage device with high efficiency.

It is a figure which shows schematic structure of the moving body which concerns on 1st Embodiment of this invention. It is a figure which shows the efficiency of a bidirectional | two-way DC-DC converter. It is a figure which shows schematic structure of the moving body which concerns on 2nd Embodiment of this invention. It is a flowchart which shows operation | movement of the solar charging system with which the mobile body which concerns on 3rd Embodiment of the invention is mounted. It is a figure which shows schematic structure of the solar charge system of a comparative example.

  Embodiments of the present invention will be described below with reference to the drawings.

<First Embodiment>
FIG. 1 is a diagram showing a schematic configuration of a moving body according to the first embodiment of the present invention. In FIG. 1, connection lines connected to the ground potential are not shown. The moving body shown in FIG. 1 is, for example, an electric vehicle or an electric motorcycle, and includes a solar panel 1, MPPT2, a battery management unit 3, a sub-battery 4, and n (n is a natural number of 2 or more) bidirectional DC-DC. A solar charging system including converters 5_1 to 5_n, a control circuit 6, a battery management unit 7, and a main battery 8, an inverter 9, and a motor 10 are provided.

  The solar panel 1 has a plurality of solar cells arranged in a panel shape, and is provided, for example, on the roof of an electric vehicle.

  The MPPT 2 is a DC-DC converter that controls the operating point of the solar panel 1 in order to maximize the power generated by the solar panel 1. The output end of the solar panel 1 is connected to the input end of the MPPT 2, and the output end of the MPPT 2 is connected to the sub battery 4.

  The battery management unit 3 manages the sub-battery 4 and controls charging / discharging of the sub-battery 4.

  The battery management unit 7 manages the main battery 8 and controls charging / discharging of the main battery 8.

  In the present embodiment, the voltage of the main battery 8 is larger than the voltage of the sub battery 4. For example, by setting the voltage range of the main battery 8 to 100 to 600 V and the voltage range of the sub battery to 10 to 48 V, the voltage range of the main battery 8 becomes a range suitable for driving the motor 10, and the voltage range of the sub battery Is in a range suitable for charging the power generated by the solar panel 1.

  The n bidirectional DC-DC converters 5 </ b> _ <b> 1 to 5 </ b> _n transmit power between the sub battery 4 and the main battery 8. The first input / output terminals T1 of the n bidirectional DC-DC converters 5_1 to 5_n are connected to the sub-battery 4 through the battery management unit 3, and the first bidirectional DC-DC converters 5_1 to 5_n are connected to the sub-battery 4, respectively. Two input / output terminals T2 are connected to the main battery 8 via the battery management unit 7.

  The control unit 6 controls the number of operations and the transmission power (output voltage or output current) of the n bidirectional DC-DC converters 5_1 to 5_n.

  The inverter 9 converts the DC voltage output from the main battery 8 into an AC voltage for driving the motor. The motor 10 is rotationally driven by a motor driving AC voltage output from the inverter 9. The driving wheel of the moving body is rotated by the rotation of the motor 10. Regenerative energy generated by the motor 10 during braking of the moving body is recovered by the battery management unit 7 and stored in the main battery 8. The DC voltage output from the sub-battery 4 is also used as a power source for electrical components such as headlights.

  Here, the reason why the solar charging system mounted on the moving body shown in FIG. 1 is highly efficient when the maximum generated power of the solar panel 1 is 200 W will be described. In order to operate the battery management unit 7 that manages the main battery 8, it is necessary to operate an ECU that manages the energy of the entire moving body, and power of 50 W is used. The battery management unit 3 controls the sub-battery 3 and can operate independently without operating the ECU, and the power consumption is sufficiently smaller than when the battery management unit 7 is operated. Further, the battery management unit 3 may not be provided.

  In the solar charging system mounted on the moving body shown in FIG. 1, the sub-battery 4 is charged with the generated power of the solar panel 1 by operating the battery management unit 7 by charging the sub-battery 4 with power. Loss from 200 W at maximum sunshine (loss in wire (1%), loss in MTTP2 (9%), loss in battery management unit 3 (5 W), charge loss of sub-battery 4 (2 .5%)) can be charged to the sub-battery 4 (171 W, efficiency 85.5%). Then, the power charged in the sub-battery 4 is charged into the main battery 8 by power transmission of, for example, 1500 W, so that the loss other than the battery management unit 3 from 1500 W (loss (1%) in the electric wire, bidirectional DC-DC) Loss in converters 5_1 to 5_n (13%), discharge loss of sub battery 4 (2.5%), charge loss of main battery 8 (2.5%), loss in battery management unit 7 (50W)) The drawn power (1228 W, efficiency 81.9%) can be charged to the main battery 8. The solar panel 1 to the main battery 8 can be charged with an efficiency of 70%. Further, even when the generated power of the solar panel 1 is low, such as in cloudy or winter, the efficiency of the MTT 2, the efficiency of the sub-battery 4, and the efficiency of the bidirectional DC-DC converters 5_1 to 5_n can be maintained. As a result, when the power charged in the sub battery 4 is charged into the main battery 8 by power transmission of 1500 W, the efficiency of power transmission from the solar panel 1 to the main battery 8 is about 70% regardless of the generated power of the solar panel 1. Can be.

  On the other hand, as in the comparative example shown in FIG. 5, the solar panel 100 and the battery 101 for driving the motor of the motor driving mechanism are directly connected (connected without passing through other batteries) via the MTTP 102. If the configuration is the same as that of the solar charging system disclosed in Patent Documents 1 to 3, the maximum generated power of the solar panel 100 is 200 W, and the battery 101 is managed to charge / discharge the battery 101. Assuming that the operating power of the battery management unit 103 to be controlled is 50 W, loss from 200 W at the time of maximum sunshine (loss on the electric wire (1%), loss on the MTTP 102 (13%), loss on the battery management unit 103 ( 50W), the battery 101 can only be charged by subtracting the charging loss (2.5%)) of the battery 101, and charging The rate will be 59%. In addition, when the generated power of the solar panel 100 is low, such as cloudy or in winter, the transmission efficiency is further reduced. For example, when 100 W of power is generated by the solar panel 1, the charging efficiency is 34%.

  As described above, the solar charging system mounted on the moving body shown in FIG. 1 can achieve higher efficiency than the comparative example shown in FIG.

  When the moving body is operating, the power of the sub battery 4 is consumed by electrical components such as lighting of the headlights, car navigation system, and air conditioning fan, and the SOC (state of charge) of the sub battery 4 is reduced. Power transmission to the sub-battery 4 may be required. The power transmitted from the main battery 8 to the sub-battery 4 may be determined depending on how much power of the sub-battery 4 is used, but here it is set to about 200 Wh.

  On the other hand, since the electric power transmitted from the sub battery 4 to the main battery 8 is, for example, 1500 W for high efficiency, the bidirectional DC-DC converter that transmits electric power between the sub battery 4 and the main battery 8. Requires a transmission capacity (power capacity) of about 1000 W to 2500 W.

  Here, unlike the solar charging system mounted on the mobile body shown in FIG. 1, the bidirectional DC-DC converter that transmits power between the sub battery 4 and the main battery 8 has a power transmission capacity of about 1000 W to 2500 W. 2A, the efficiency of a single bidirectional DC-DC converter having a power transmission capability of about 1000 W to 2500 W is as shown in FIG. Inefficiency in transmission.

  On the other hand, the solar charging system mounted on the moving body shown in FIG. 1 is configured to include n bidirectional DC-DC converters 5_1 to 5_n that transmit electric power between the sub battery 4 and the main battery 8. Therefore, for example, n = 3, and each of the bidirectional DC-DC converters 5_1 to 5_3 is a bidirectional DC-DC converter having a transmission capability of about 500W, and among the bidirectional DC-DC converters 5_1 to 5_3 when transmitting less than 500W Only one of the two-way DC-DC converters 5_1 to 5_3 is operated at the time of power transmission of 500 W or more and less than 1000 W, and all of the two-way DC-DC converters 5_1 to 5_3 are operated at the time of power transmission of 1000 W or more. , The overall efficiency of the bidirectional DC-DC converters 5_1 to 5_3 is as shown in FIG. As it is shown in. Thereby, not only the power transmission from the sub battery 4 to the main battery 8 but also the power transmission from the main battery 8 to the sub battery 4 becomes highly efficient.

  Unlike the above-described example, there may be a plurality of types of power capacities of the n bidirectional DC-DC converters 5_1 to 5_n. For example, n = 2, the bidirectional DC-DC converter 5_1 is a bidirectional DC-DC converter having a transmission capability of about 500W, and the bidirectional DC-DC converter 5_2 is a bidirectional DC-DC having a transmission capability of about 1000W. As the converter, only the bidirectional DC-DC converter 5_1 is operated when transmitting less than 500W, only the bidirectional DC-DC converter 5_2 is operated when transmitting 500W or more and less than 1000W, and the bidirectional DC-DC converter is operated when transmitting 1000W or more. 5_1 and 5_2 may be operated. As described above, the power capacity of the n number of bidirectional DC-DC converters 5_1 to 5_n exists in a plurality of types, so that high-efficiency power with a wide range of transmission power can be achieved with a small number of bidirectional DC-DC converters. Electric transmission can be realized.

  Note that the n bidirectional DC-DC converters 5_1 to 5_n are preferably isolated DC-DC converters. According to such a structure, since the solar panel 1, the sub battery 4, and the main battery 8 can be insulated, safety improves. At this time, if MPPT2 is made non-insulating, MPPT2 can be produced at low cost while ensuring safety.

Second Embodiment
FIG. 3 is a diagram showing a schematic configuration of a moving body according to the second embodiment of the present invention. In FIG. 3, the connection lines connected to the ground potential are not shown. In FIG. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals, and detailed description thereof is omitted.

  The moving body shown in FIG. 3 has a configuration in which switches SW1 and SW2 and a path 11 are added to the moving body shown in FIG. The switch SW1 is a switch that selectively selects the sub battery 4 or the path 11 as a connection destination of the output end of the MTTP2. The switch SW2 is a switch that selectively selects the sub battery 4 or the path 11 as a connection destination of the first input / output terminals T1 of the n bidirectional DC-DC converters 5_1 to 5_n.

  When both the switches SW1 and SW2 select the path 11, the path connecting the output terminal of the MPPT 2 and the first input / output terminals 1 of the n bidirectional DC-DC converters 5_1 to 5_n without passing through the sub-battery 4. Is formed.

  When the moving body is not operating, both the switches SW1 and SW2 automatically select the sub battery 4. On the other hand, when the moving body is operating, the battery management unit 7 also operates, so that the battery management unit 7 controls the switches SW1 and SW2, and charging from the main battery 8 to the sub battery 4 is unnecessary and the sub When the amount of electric power that can be output from the battery 4 is equal to or greater than a predetermined value, the generated power from the solar panel 1 can be charged to the main battery 8 via the path 11 without passing through the sub-battery 4.

  When the mobile body is operating, the battery management unit 7 is inevitably operating, so that the loss of the battery management unit 7 does not need to be considered when considering the efficiency of the solar charging system. Then, when the moving body is operating, charging the sub-battery 4 once with the generated power from the solar panel 1 causes charge / discharge loss of the sub-battery 4, resulting in poor efficiency. Therefore, when the moving body is operating, charging from the main battery 8 to the sub-battery 4 is unnecessary, and the amount of power that can be output from the sub-battery 4 is greater than or equal to a predetermined value, the solar panel is The configuration in which the main battery 8 can be charged with the generated power from 1 via the path 11 without passing through the sub-battery 4 is more efficient than the first embodiment.

  When the switches SW1 and SW2 both select the path 11, the power supplied to the first input / output terminals 1 of the n bidirectional DC-DC converters 5_1 to 5_n depends on the generated power of the solar panel 1. However, the control circuit 6 controls the number of n bidirectional DC-DC converters 5_1 to 5_n in response to this change, so that the n bidirectional DC-DC converters 5_1 to 5 are controlled. The overall efficiency of 5_n can be increased.

<Third Embodiment>
The schematic configuration of the moving body according to the third embodiment of the present invention is the same as the schematic configuration of the moving body according to the first embodiment of the present invention.

  The solar charging system mounted on the mobile body according to the third embodiment of the present invention is configured so that the sub battery 4 and the main battery 8 are connected to the main battery 8 by the operation shown in FIG. Electric power is transmitted to and from the battery 8. Note that a first predetermined value P1, a second predetermined value P2, a third predetermined value P3, and a fourth predetermined value P4, which will be described later, have a third predetermined value P3 smaller than the first predetermined value P1, and a third predetermined value P3. Is set to be larger than the fourth predetermined value P4, and the fourth predetermined value P4 is set to be larger than the second predetermined value P2, and is stored in, for example, the built-in memory of the battery management unit 3 or the control circuit 6.

  First, the battery management unit 3 determines whether the amount of power that can be output by the sub-battery 4 is equal to or greater than a first predetermined value P1 (step S10). For example, when the SOC of the sub-battery 4 is 95% or more, the amount of power that can be output by the sub-battery 4 may be regarded as being equal to or greater than the first predetermined value P1.

  When it is determined that the amount of power that can be output by the sub-battery 4 is equal to or greater than the first predetermined value P1 (YES in step S10), the sub-battery is controlled by the battery management unit 3, the control circuit 6, and the battery management unit 7. Power transmission from 4 to the main battery 8 is performed, and the main battery 8 is charged (step S20).

  In step S30 following step S20, the battery management unit 3 determines whether the amount of power that can be output by the sub-battery 4 is equal to or less than a third predetermined value P3 (step S30). For example, when the SOC of the sub-battery 4 is 75% or less, the amount of power that can be output by the sub-battery 4 may be regarded as being the third predetermined value P3 or less.

  When it is not determined that the amount of power that can be output by the sub-battery 4 has become equal to or less than the third predetermined value P3 (NO in step S30), the process returns to step S20, and charging of the main battery 8 is continued. On the other hand, when it is determined that the amount of power that can be output by the sub-battery 4 has become equal to or less than the third predetermined value P3 (YES in step S30), the control of the battery management unit 3, the control circuit 6, and the battery management unit 7 The power transmission from the sub battery 4 to the main battery 8 is terminated, the charging of the main battery 8 is terminated (step S40), and the process returns to step S10.

  If it is not determined in step S10 that the amount of power that can be output by the sub-battery 4 is greater than or equal to the first predetermined value P1 (NO in step S10), the battery management unit 3 outputs the sub-battery 4 It is determined whether the possible amount of power is equal to or less than a second predetermined value P2 (step S50). For example, when the SOC of the sub-battery 4 is 60% or less, the amount of power that can be output by the sub-battery 4 may be regarded as being equal to or less than the second predetermined value P2.

  When it is determined that the amount of power that can be output by the sub-battery 4 is equal to or less than the second predetermined value P2 (YES in step S50), the battery management unit 3 supplies n bidirectional DC-DC converters 5-1 to the switch SW1. To 5_n, the battery management unit 7 causes the switch SW2 to select n bidirectional DC-DC converters 5-1 to 5_n, and the control of the battery management unit 3, the control circuit 6, and the battery management unit 7 Power transmission from the main battery 8 to the sub battery 4 is performed, and the sub battery 4 is charged (step S60).

  In step S70 following step S60, the battery management unit 3 determines whether the amount of power that can be output by the sub-battery 4 is equal to or greater than a fourth predetermined value P4 (step S70). For example, when the SOC of the sub-battery 4 is 70% or more, the amount of power that can be output by the sub-battery 4 may be regarded as being equal to or greater than the fourth predetermined value P4.

  When it is not determined that the amount of power that can be output by the sub battery 4 has become equal to or greater than the fourth predetermined value P4 (NO in step S70), the process returns to step S60, and charging of the sub battery 4 is continued. On the other hand, when it is determined that the amount of power that can be output from the sub-battery 4 is equal to or greater than the fourth predetermined value P4 (YES in step S70), the control of the battery management unit 3, the control circuit 6, and the battery management unit 7 Power transmission from the main battery 8 to the sub battery 4 is terminated, charging of the sub battery 4 is terminated (step S80), and the process returns to step S10.

  When the SOCs of the sub battery 4 and the main battery 8 are each 100%, the charging of the sub battery 4 using the power generated by the solar panel 1 is terminated.

<Others>
It should be noted that the contents of the preferred embodiments described as appropriate in the above-described embodiments and the above-described embodiments can be implemented in any combination as long as there is no contradiction. For example, in the second embodiment, similarly to the third embodiment, when the SOCs of the sub battery 4 and the main battery 8 become 100%, charging of the sub battery 4 using the generated power of the solar panel 1 is performed. It is preferable to end. Furthermore, in the third embodiment, since the main battery 8 may be charged using the generated power of the solar panel 1, when the SOC of the sub battery 4 and the main battery 8 becomes 100%, the solar panel It is preferable to end the charging of the sub battery 4 or the main battery 8 using the generated power of one.

1,100 Solar panel 2,102 MPPT
3, 7, 103 Battery management unit 4 Sub battery 5_1 to 5_n Bidirectional DC / DC converter 6 Control unit 8 Main battery 9 Inverter 10 Motor 11 Path 101 Battery SW1 to SW2 Switch

Claims (10)

Solar cells,
MPPT (Maximum Power Point Tracking) for controlling the operating point of the solar cell in order to maximize the generated power of the solar cell;
A first power storage device;
A second power storage device;
A plurality of bidirectional DC-DC converters for transmitting power between the first power storage device and the second power storage device;
A control unit for controlling the number of operations of the plurality of bidirectional DC-DC converters,
The output end of the solar cell is connected to the input end of the MPPT,
An output terminal of the MPPT is connected to the first power storage device;
Each first input / output terminal of the plurality of bidirectional DC-DC converters is connected to the first power storage device,
The solar charging system, wherein each second input / output terminal of the plurality of bidirectional DC-DC converters is connected to the second power storage device.   The solar charging system according to claim 1, wherein each of the plurality of bidirectional DC-DC converters is an isolated DC-DC converter. When the amount of power that can be output by the first power storage device is equal to or greater than a first predetermined value, at least one of the plurality of bidirectional DC-DC converters transmits power from the first power storage device to the second power storage device. Charging the second power storage device,
When the amount of power that can be output by the first power storage device is equal to or less than a second predetermined value, at least one of the plurality of bidirectional DC-DC converters transmits power from the second power storage device to the first power storage device. Charging the first power storage device,
The solar charging system according to claim 1 or 2, wherein the second predetermined value is smaller than the first predetermined value. When the amount of power that can be output by the first power storage device is equal to or less than a third predetermined value, power transmission from the first power storage device to the second power storage device is terminated, and charging of the second power storage device is terminated.
When the amount of power that can be output by the first power storage device is equal to or greater than a fourth predetermined value, power transmission from the second power storage device to the first power storage device is terminated, and charging of the first power storage device is terminated.
The third predetermined value is smaller than the first predetermined value, the third predetermined value is larger than the fourth predetermined value, and the fourth predetermined value is larger than the second predetermined value. Solar charging system.   The solar charging system according to any one of claims 1 to 4, wherein a plurality of types of power capacities of the plurality of bidirectional DC-DC converters exist.   6. The apparatus according to claim 1, further comprising a path that connects the output end of the MPPT and the first input / output terminals of the plurality of bidirectional DC-DC converters without passing through the first power storage device. The solar charging system described.   When the SOC of the first power storage device and the SOC of the second power storage device are both 100%, charging of the first power storage device or the second power storage device using the generated power of the solar battery is performed. The solar charging system according to any one of claims 1 to 6, which is terminated.   The solar charging system according to claim 1, wherein a voltage of the second power storage device is higher than a voltage of the first power storage device.   A mobile body comprising the solar charging system according to claim 1.   The mobile body according to claim 9, wherein the power output from the second power storage device included in the solar charging system is used as power for driving the mobile body.

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