In-vehicle power control device

Abstract

An in-vehicle power control device (10) comprises: a power adjustment unit (30) that performs an adjustment operation for adjusting power input from a solar cell unit (2) and outputting the adjusted power to an output-side conduction path (21); a control unit (35) that operates upon receiving power supply from an input-side conduction path (20) between the solar cell unit (2) and the power adjustment unit (30); a battery-side power path (24) provided between the control unit (35) and a battery (3); and a switch unit (32). The control unit (35) monitors the voltage of the input-side conductive path (20) in a state in which the power adjustment unit (30) is stopped and the switch unit (32) is maintained in an off-state, switches the switch unit (32) to an on-state when the voltage of the input-side conductive path (20) exceeds a threshold value, causes the power adjustment unit (30) to perform the adjustment operation, and performs confirmation processing for confirming the power generation amount of the solar cell unit (2).

Description

In-vehicle power control device

[0001] The present disclosure relates to an in-vehicle power control device.

[0002] Patent Document 1 discloses a solar power generation system mounted on a vehicle. This solar power generation system includes a solar cell panel and a power converter. The power converter is connected between the solar cell panel and a battery. The power converter converts the power generated by the solar cell panel and inputs it to the battery.

[0003] Japanese Patent Application Laid-Open No. 2021-62841

[0004] In the configuration of Patent Document 1, if the power converter is started after the amount of power generated by the solar cell panel has reached a sufficient level, it is necessary to determine whether the amount of power generated is sufficient. One possible method for determining this is for the control unit to monitor a threshold value for the output voltage of the solar cell panel and, if the threshold value is exceeded, have the power converter perform power conversion to check the amount of power generated. However, this method requires power consumption by the control unit, which monitors the output voltage and checks the amount of power generated. If this power consumption is covered by battery power, there is a concern that the battery voltage may drop. Furthermore, if this power consumption is covered by power generated by the solar cell panel, there is a concern that the control unit may run out of power while checking the amount of power generated when the control unit has the power converter perform power conversion.

[0005] The present disclosure aims to provide a technology that can prevent a battery voltage drop while preventing a power shortage in a control unit while checking the amount of power generation.

[0006] The on-board power control device of the present disclosure is an on-board power control device mounted on a vehicle having a solar cell unit and a battery, and comprises: a power adjustment unit that performs an adjustment operation to adjust power input from the solar cell unit and output it to an output-side conductive path; a control unit that operates by receiving power supply from the input-side conductive path between the solar cell unit and the power adjustment unit; a battery-side power path provided between the control unit and the battery; and a switch unit that is provided on the battery-side power path and switches between an on state that allows power supply from the battery to the control unit and an off state that blocks it, wherein the control unit monitors the voltage of the input-side conductive path while stopping the power adjustment unit and maintaining the switch unit in an off state, and when the voltage of the input-side conductive path exceeds a threshold, switches the switch unit to an on state and causes the power adjustment unit to perform the adjustment operation, and performs a confirmation process to confirm the amount of power generated by the solar cell unit.

[0007] According to the present disclosure, it is possible to suppress a drop in the battery voltage while suppressing a power shortage in the control unit while checking the amount of power generation.

[0008] Fig. 1 is a configuration diagram of a vehicle equipped with an on-board power control device according to a first embodiment, and Fig. 2 is a flowchart of processing performed by a control unit of the on-board power control device according to the first embodiment.

[0009] [Description of Embodiments of the Present Disclosure] In the following, embodiments of the present disclosure are listed and illustrated.

[0010] [1] An on-board power control device mounted on a vehicle having a solar cell unit and a battery, comprising: a power adjustment unit that performs an adjustment operation to adjust power input from the solar cell unit and output it to an output-side conductive path; a control unit that operates by receiving power supply from the input-side conductive path between the solar cell unit and the power adjustment unit; a battery-side power path provided between the control unit and the battery; and a switch unit that is provided on the battery-side power path and switches between an on state that allows power supply from the battery to the control unit and an off state that blocks power supply from the battery, wherein the control unit monitors the voltage of the input-side conductive path while stopping the power adjustment unit and maintaining the switch unit in an off state, and when the voltage of the input-side conductive path exceeds a threshold, switches the switch unit to an on state and causes the power adjustment unit to perform the adjustment operation, and performs a confirmation process to confirm the amount of power generated by the solar cell unit.

[0011] When the solar cell unit generates power, the output voltage of the solar cell unit is applied to the input-side conductive path. The control unit receives power from the input-side conductive path and can monitor the voltage of the input-side conductive path. During this time, the switch unit is maintained in the off state, so power from the battery is not supplied to the control unit, and a drop in the battery voltage is suppressed. When the voltage of the input-side conductive path exceeds a threshold, the control unit switches the switch unit to the on state and causes the power adjustment unit to perform an adjustment operation to check the amount of power generated by the solar cell unit. This allows the control unit to check the amount of power generated by the solar cell unit while receiving power from the battery. This prevents the control unit from running out of power while checking the amount of power generated. In other words, the above-mentioned on-board power control device can prevent a drop in the battery voltage and prevent the control unit from running out of power while checking the amount of power generated.

[0012] [2] The in-vehicle power control device described in [1], wherein, if the control unit determines, as a result of the confirmation process, that the amount of power generated by the solar cell unit is insufficient, the control unit stops the power adjustment unit, switches the switch unit to the off state, and performs the confirmation process again after a predetermined time has elapsed.

[0013] When the vehicle power control device determines that the amount of power generated by the solar cell unit is insufficient, it does not continuously repeat the checking process, but instead temporarily stops the power adjustment unit and switches the switch unit to the off state to reduce battery power consumption, thereby reducing the average value of the output current from the battery.

[0014] [3] The in-vehicle power control device according to [2], wherein the predetermined time is set to be equal to or greater than 10 seconds and equal to or less than 1 hour.

[0015] In the above-described on-board power control device, the predetermined time is set to be equal to or greater than 10 seconds and equal to or less than 1 hour, so that the average value of the output current from the battery can be appropriately reduced.

[0016] [4] An on-board power control device according to any one of [1] to [3], comprising: a power path provided between the input side conductive path and the control unit; a first diode provided in the power path; a second diode provided in the battery side power path; and a conductive path provided between the output side conductive path and the battery, wherein the battery side power path is provided between the power path and the conductive path, the first diode allows current to flow from the input side conductive path side to the control unit side through itself and blocks current flowing from the battery side power path side to the input side conductive path side through itself, and the second diode allows current to flow from the conductive path side to the power path side through itself and blocks current flowing from the power path side to the conductive path side through itself.

[0017] The above-mentioned in-vehicle power control device can prevent a short circuit between the solar cell unit and the battery by using the second diode when power is supplied from the solar cell unit to the control unit via the power path. Also, the above-mentioned in-vehicle power control device can prevent a short circuit between the solar cell unit and the battery by using the first diode when power is supplied from the battery to the control unit via the battery-side power path.

[0018] [5] An on-board power control device according to any one of [1] to [3], comprising: a power path provided between the input side conductive path and the control unit; a first diode provided in the power path; and a second diode provided in the battery side power path, wherein the output side conductive path is electrically connected to the battery, and the battery side power path is provided between the power path and the output side conductive path, the first diode allows current to flow from the input side conductive path side to the control unit side through itself, and blocks current flowing from the battery side power path side to the input side conductive path side through itself, and the second diode allows current to flow from the output side conductive path side to the power path side through itself, and blocks current flowing from the power path side to the output side conductive path side through itself.

[0019] The above-mentioned in-vehicle power control device can prevent a short circuit between the solar cell unit and the battery by using the second diode when power is supplied from the solar cell unit to the control unit via the power path. Also, the above-mentioned in-vehicle power control device can prevent a short circuit between the solar cell unit and the battery by using the first diode when power is supplied from the battery to the control unit via the battery-side power path.

[0020] [Details of the embodiments of the present disclosure] 1. First embodiment Fig. 1 shows a vehicle 1 equipped with an on-board power control device 10 according to a first embodiment. The vehicle 1 includes a solar cell unit 2 and a battery 3.

[0021] The solar cell unit 2 is configured by connecting a plurality of solar cell cells that convert light energy into electric power, for example, and outputs electric power generated by the plurality of solar cell cells in response to irradiated light.

[0022] The battery 3 is, for example, a main battery for driving the vehicle or an auxiliary battery.

[0023] The on-board power control device 10 mounted on the vehicle 1 includes an input side conductive path 20, an output side conductive path 21, a conductive path 22, a power path 23, a battery side power path 24, a power adjustment unit 30, a voltage conversion unit 31, a switch unit 32, a first diode 33, a second diode 34, and a control unit 35.

[0024] The power adjustment unit 30 is provided between the input-side conductive path 20 and the output-side conductive path 21. The input-side conductive path 20 is connected to the solar cell unit 2. Power generated by the solar cell unit 2 is supplied to the input-side conductive path 20. The power adjustment unit 30 adjusts the power input from the solar cell unit 2 via the input-side conductive path 20 and outputs it to the output-side conductive path 21. The power adjustment unit 30 operates under the control of the control unit 35 using an MPPT (Maximum Power Point Tracking) method. The power adjustment unit 30 is configured by, for example, a DC-DC converter.

[0025] A conductive path 22 is provided between the output-side conductive path 21 and the battery 3. A voltage conversion unit 31 is provided between the output-side conductive path 21 and the conductive path 22. The voltage conversion unit 31 performs a conversion operation of increasing or decreasing the voltage input from the output-side conductive path 21 and applying the voltage to the conductive path 22. A high-potential terminal of the battery 3 is electrically connected to the conductive path 22. As the voltage conversion unit 31 performs a conversion operation, power is supplied from the voltage conversion unit 31 to the battery 3, and the battery 3 is charged. The voltage conversion unit 31 is configured, for example, by a DC-DC converter.

[0026] The power path 23 is provided between the input side conductive path 20 and the control unit 35. The power path 23 is electrically connected to the input side conductive path 20 and the control unit 35, and transmits power between the input side conductive path 20 and the control unit 35.

[0027] The battery-side power path 24 is provided between the power path 23 and the conductive path 22. The battery-side power path 24 is electrically connected to the power path 23 and the conductive path 22, and transmits power between the power path 23 and the conductive path 22. In other words, the battery-side power path 24 is provided between the battery 3 and the control unit 35, and transmits power between the battery 3 and the control unit 35.

[0028] The switch unit 32 is provided on the battery-side power path 24. The switch unit 32 switches between an ON state, which allows power to be supplied from the conductive path 22 to the power path 23, and an OFF state, which cuts off the power supply from the conductive path 22 to the power path 23. When in the ON state, the switch unit 32 allows power to be supplied from the battery 3 to the control unit 35. When in the OFF state, the switch unit 32 cuts off the power supply from the battery 3 to the control unit 35. The switch unit 32 is preferably a normally-off type.

[0029] The first diode 33 is provided in the power path 23. The first diode 33 is provided closer to the input-side conductive path 20 than the connection portion of the power path 23 with the battery-side power path 24. The first diode 33 allows current to flow from the input-side conductive path 20 to the control unit 35 through the first diode 33. The first diode 33 blocks current flowing from the battery-side power path 24 to the input-side conductive path 20 through the first diode 33.

[0030] The second diode 34 is provided in the battery-side power path 24. The second diode 34 is connected in series with the switch unit 32 between the conductive path 22 and the power path 23. The second diode 34 allows current to flow from the conductive path 22 side to the power path 23 side through the second diode 34. The second diode 34 blocks current flowing from the power path 23 side to the conductive path 22 side through the second diode 34.

[0031] The control unit 35 includes, for example, a microcomputer. The control unit 35 causes the power adjustment unit 30 to perform an adjustment operation so that the output power is maximized. The control unit 35 causes the voltage conversion unit 31 to perform a conversion operation so that the output voltage becomes a target voltage. The control unit 35 controls the switch unit 32.

[0032] The control unit 35 operates by receiving power supplied from the input side conductive path 20 via the power path 23. When power is generated in the solar cell unit 2, the generated power is supplied to the control unit 35 via the input side conductive path 20 and the power path 23.

[0033] The control unit 35 performs a confirmation process. The confirmation process is a process in which the voltage of the input-side conductive path 20 is monitored while the power adjustment unit 30 is stopped and the switch unit 32 is maintained in the OFF state, and when the voltage of the input-side conductive path 20 exceeds a threshold, the control unit 35 switches the switch unit 32 to the ON state and causes the power adjustment unit 30 to perform an adjustment operation, thereby confirming the amount of power generated by the solar cell unit 2. The control unit 35 causes the voltage conversion unit 31 to perform a conversion operation in parallel with the adjustment operation by the power adjustment unit 30.

[0034] The in-vehicle power control device 10 includes a voltage detection unit 40 and a current detection unit 41. The voltage detection unit 40 detects the voltage of the input-side conductive path 20. The voltage detection unit 40 is configured, for example, by a known voltage detection circuit. The voltage detection unit 40 outputs a signal indicating the voltage of the input-side conductive path 20. The control unit 35 determines the voltage of the input-side conductive path 20 based on the signal output from the voltage detection unit 40. The current detection unit 41 detects the current flowing through the input-side conductive path 20. The current detection unit 41 is configured, for example, by a known current sensor. The current detection unit 41 outputs a signal indicating the value of the current flowing through the input-side conductive path 20. The control unit 35 calculates the amount of power generated by the solar cell unit 2 based on the signal output from the voltage detection unit 40 and the signal output from the current detection unit 41.

[0035] If the control unit 35 determines as a result of the confirmation process that the amount of power generated by the solar cell unit 2 is insufficient, it stops the power adjustment unit 30 and the voltage conversion unit 31, switches the switch unit 32 to the off state, and performs the confirmation process again after a predetermined time has elapsed. The predetermined time is set to, for example, 10 seconds or more and 1 hour or less.

[0036] 2 when a start condition is met. The start condition is, for example, that a start switch of the vehicle 1 is switched to the on state. The start switch is, for example, an ignition switch or a power switch.

[0037] First, in step S10, the control unit 35 determines whether the voltage of the input-side conductive path 20 exceeds the threshold value. If the control unit 35 determines that the voltage of the input-side conductive path 20 does not exceed the threshold value, the control unit 35 returns to step S10. That is, the control unit 35 repeats the processing of step S10 until it determines that the voltage of the input-side conductive path 20 exceeds the threshold value. During this time, the control unit 35 stops the power adjustment unit 30 and the voltage conversion unit 31 and keeps the switch unit 32 in the off state.

[0038] If the control unit 35 determines that the voltage of the input-side conductive path 20 exceeds the threshold, it switches the switch unit 32 to the ON state in step S11, and causes the power adjustment unit 30 to start an adjustment operation and the voltage conversion unit 31 to start a conversion operation in step S12. Then, in step S13, the control unit 35 determines whether the amount of power generated by the solar cell unit 2 is sufficient. For example, the control unit 35 determines that the amount of power generation is sufficient when the amount of power generation exceeds a predetermined judgment value, and determines that the amount of power generation is insufficient when the amount of power generation is equal to or less than the judgment value.

[0039] If the control unit 35 determines that the amount of power generated is sufficient, in step S14, the control unit 35 switches the switch unit 32 to the OFF state. In step S15, the control unit 35 continues the adjustment operation by the power adjustment unit 30 and the conversion operation by the voltage conversion unit 31, thereby supplying the power generated by the solar cell unit 2 to the battery 3.

[0040] If the control unit 35 determines that the amount of power generation is insufficient, then in step S16, the control unit 35 switches the switch unit 32 to the OFF state. In step S17, the control unit 35 stops the adjustment operation by the power adjustment unit 30 and the conversion operation by the voltage conversion unit 31. Then, in step S18, the control unit 35 determines whether or not a predetermined time has elapsed. If the control unit 35 determines that the predetermined time has not elapsed, the control unit 35 returns to step S18. That is, the control unit 35 repeats the process of step S18 until it determines that the predetermined time has elapsed. During this time, no current is supplied from the solar cell unit 2 to the battery 3.

[0041] If the control unit 35 determines that the predetermined time has elapsed, the control unit 35 returns to the process of step S10 and performs the confirmation process (i.e., the processes of steps S10 to S13). In other words, the control unit 35 performs the confirmation process every time the predetermined time has elapsed until the amount of power generation becomes sufficient.

[0042] As described above, in the in-vehicle power control device 10, when the solar cell unit 2 generates power, the output voltage of the solar cell unit 2 is applied to the input-side conductive path 20. The control unit 35 receives power from the input-side conductive path 20 and can monitor the voltage of the input-side conductive path 20. During this period, the switch unit 32 is maintained in the OFF state, so power from the battery 3 is not supplied to the control unit 35, and a voltage drop in the battery 3 is suppressed. When the voltage of the input-side conductive path 20 exceeds a threshold, the control unit 35 switches the switch unit 32 to the ON state, causes the power adjustment unit 30 to perform an adjustment operation, and causes the voltage conversion unit 31 to perform a conversion operation, thereby checking the amount of power generated by the solar cell unit 2. This allows the control unit 35 to check the amount of power generated by the solar cell unit 2 while receiving power from the battery 3. This prevents the control unit 35 from running out of power while checking the amount of power generated. In other words, the in-vehicle power control device 10 can prevent a voltage drop in the battery 3 while also preventing a power shortage in the control unit 35 while checking the amount of power generated.

[0043] Furthermore, when the in-vehicle power control device 10 determines that the amount of power generated by the solar cell unit 2 is insufficient, it does not continuously repeat the confirmation process, but temporarily stops the power adjustment unit 30 and switches the switch unit 32 to the off state, thereby reducing the power consumption of the battery 3. This makes it possible to reduce the average value of the output current from the battery 3.

[0044] Furthermore, the in-vehicle power control device 10 can appropriately reduce the average value of the output current from the battery 3 by setting the predetermined time to be equal to or greater than 10 seconds and equal to or less than 1 hour.

[0045] Furthermore, the in-vehicle power control device 10 can prevent the solar cell unit 2 and the battery 3 from shorting out by the second diode 34 when power is supplied from the solar cell unit 2 to the control unit 35 via the power path 23. Furthermore, the in-vehicle power control device 10 can prevent the solar cell unit 2 and the battery 3 from shorting out by the first diode 33 when power is supplied from the battery 3 to the control unit 35 via the battery-side power path 24.

[0046] <Other Embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments are also included within the technical scope of the present invention. Furthermore, various features of the above-mentioned embodiments and the embodiments to be described later may be combined in any manner as long as they are not contradictory.

[0047] In the first embodiment, only one combination of a solar cell unit and a power adjustment unit is provided, but a configuration in which a plurality of combinations of a solar cell unit and a power adjustment unit are provided may also be used.

[0048] The in-vehicle power control device does not have to include a voltage conversion unit, in which case the power adjustment unit may also have the function of the voltage conversion unit.

[0049] It should be noted that the embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. The scope of the present invention is not limited to the embodiments disclosed herein, and is intended to include all modifications within the scope indicated by the claims or within the scope equivalent to the claims.

[0050] REFERENCE SIGNS LIST 1 vehicle 2 solar cell unit 3 battery 10 on-vehicle power control device 20 input side conductive path 21 output side conductive path 22 conductive path 23 power path 24 battery side power path 30 power adjustment unit 31 voltage conversion unit 32 switch unit 33 first diode 34 second diode 35 control unit 40 voltage detection unit 41 current detection unit

Claims

1. An on-board power control device mounted on a vehicle having a solar cell unit and a battery, comprising: a power adjustment unit that performs an adjustment operation to adjust power input from the solar cell unit and output it to an output-side conductive path; a control unit that operates by receiving power supply from the input-side conductive path between the solar cell unit and the power adjustment unit; a battery-side power path provided between the control unit and the battery; and a switch unit that is provided on the battery-side power path and switches between an on state that allows power supply from the battery to the control unit and an off state that blocks it, wherein the control unit monitors the voltage of the input-side conductive path while stopping the power adjustment unit and maintaining the switch unit in an off state, and when the voltage of the input-side conductive path exceeds a threshold, switches the switch unit to an on state and causes the power adjustment unit to perform the adjustment operation, and performs a confirmation process to confirm the amount of power generated by the solar cell unit.

2. The in-vehicle power control device according to claim 1, wherein, if the control unit determines, as a result of the confirmation process, that the amount of power generated by the solar cell unit is insufficient, the control unit stops the power adjustment unit, switches the switch unit to the off state, and performs the confirmation process again after a predetermined time has elapsed.

3. The vehicle-mounted power control device according to claim 2, wherein the predetermined time is set to be equal to or greater than 10 seconds and equal to or less than 1 hour.

4. An on-board power control device according to any one of claims 1 to 3, comprising: a power path provided between the input side conductive path and the control unit; a first diode provided in the power path; a second diode provided in the battery side power path; and a conductive path provided between the output side conductive path and the battery, wherein the battery side power path is provided between the power path and the conductive path, the first diode allows current to flow from the input side conductive path side to the control unit side through itself and blocks current flowing from the battery side power path side to the input side conductive path side through itself, and the second diode allows current to flow from the conductive path side to the power path side through itself and blocks current flowing from the power path side to the conductive path side through itself.

5. An on-board power control device according to any one of claims 1 to 3, comprising: a power path provided between the input side conductive path and the control unit; a first diode provided in the power path; and a second diode provided in the battery side power path, wherein the output side conductive path is electrically connected to the battery, and the battery side power path is provided between the power path and the output side conductive path, the first diode allows current to flow from the input side conductive path to the control unit through itself and blocks current flowing from the battery side power path to the input side conductive path through itself, and the second diode allows current to flow from the output side conductive path to the power path through itself and blocks current flowing from the power path to the output side conductive path through itself.

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