On-vehicle power control device

Abstract

To provide a technique capable of charging a high-voltage battery based on output power from a solar cell part with high conversion efficiency without providing a power storage part between a power adjustment part for adjusting the output power from the solar cell part and a voltage conversion part for converting an output voltage from the power adjustment part and outputting it to the high-voltage battery side.SOLUTION: The onboard power control device 1 includes a power adjustment unit 11, a first voltage conversion unit 13, a second voltage conversion unit 14, and a control unit 15. The control unit 15 charges the low-voltage battery 3 by causing the power adjustment unit 11 to perform the adjustment operation and causing the first voltage conversion unit 13 to perform the conversion operation in a state where the second voltage conversion unit 14 is stopped, and then charges the high-voltage battery 4 with the power from the low-voltage battery 3 by causing the second voltage conversion unit 14 to perform the step-up operation in a state where the power adjustment unit 11 is stopped.SELECTED DRAWING: Figure 1

Description

[Technical Field]

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

[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] Patent Document 2 discloses a power control device for an on-vehicle solar panel. This power control device has a power conversion unit, a power storage unit, and a control unit. The power conversion unit converts input power based on power supplied from the solar panel to increase or decrease voltage, and supplies output power to a conduction path. The power storage unit is charged and discharged via the conduction path. The control unit performs maximum power point tracking control on the power conversion unit. A power supply system having a battery and an isolated conversion device is mounted on a vehicle. The isolated conversion device performs a boost operation to boost a voltage applied to the conduction path and apply a voltage to the power path while insulating the power path that forms a path for supplying power to the battery from the conduction path. The control unit performs adjustment control to control the power conversion unit or the isolated conversion device so as to maintain a predetermined ratio between the charging voltage of the battery and the charging voltage of the power storage unit. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-62841 [Patent Document 2] Japanese Patent Application Laid-Open No. 2024-50378 Summary of the Invention [Problem to be solved by the invention]

[0005] In the configuration of Patent Document 1, the power supplied from the solar panel is directly converted by the power converter and input to the battery. In this configuration, the amount of power generated can vary significantly depending on the solar radiation conditions and the amount of shading while the vehicle is running. This raises concerns that the power conversion efficiency of the power converter may deteriorate.

[0006] In this regard, the configuration of Patent Document 2 uses a power storage unit, which allows the ratio between the charging voltage of the battery and the charging voltage of the power storage unit to be adjusted so as to maintain a predetermined ratio. This configuration improves conversion efficiency. However, the configuration of Patent Document 2 requires a power storage unit.

[0007] The present disclosure aims to provide a technology that enables efficient charging of a high-voltage battery based on the output power from a solar cell unit without providing a storage unit between a power adjustment unit that adjusts the output power from the solar cell unit and a voltage conversion unit that converts the output voltage from the power adjustment unit and outputs it to the high-voltage battery. [Means for solving the problem]

[0008] The in-vehicle power control device of the present disclosure includes: An on-board power control device mounted on a vehicle including a solar cell unit, a low-voltage battery, and a high-voltage battery, a power adjustment unit that performs an adjustment operation of adjusting the power input from the solar cell unit and outputting the adjusted power to the conductive path; a first voltage conversion unit that is provided between the conductive path and the low-voltage battery and performs a conversion operation of converting a voltage input from the conductive path side and outputting the converted voltage to the low-voltage battery side; a second voltage conversion unit provided between the low-voltage battery and the high-voltage battery, for performing a boost operation of boosting an input voltage and outputting the boosted voltage to the high-voltage battery; a control unit that controls the power adjustment unit, the first voltage conversion unit, and the second voltage conversion unit, The control unit charges the low-voltage battery by having the power adjustment unit perform the adjustment operation and the first voltage conversion unit perform the conversion operation while the second voltage conversion unit is stopped, and then charges the high-voltage battery with power from the low-voltage battery by having the second voltage conversion unit perform the boost operation while the power adjustment unit is stopped. [Effects of the Invention]

[0009] According to the present disclosure, it is possible to charge a high-voltage battery based on the output power from the solar cell unit with high conversion efficiency without providing a storage unit between a power adjustment unit that adjusts the output power from the solar cell unit and a voltage conversion unit that converts the output voltage from the power adjustment unit and outputs it to the high-voltage battery. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a configuration diagram of a vehicle equipped with an on-board power control device according to a first embodiment. [Figure 2] FIG. 2 is an explanatory diagram showing how power from the solar cell unit is supplied to the low-voltage battery, and then the power from the low-voltage battery is supplied to the high-voltage battery. [Figure 3] FIG. 3 is an explanatory diagram showing how power from the solar cell unit is supplied to the high-voltage battery without passing through the low-voltage battery when the control unit receives an enabling signal. [Figure 4] FIG. 4 is a configuration diagram of the power adjustment unit. [Figure 5] FIG. 5 is a configuration diagram of the first voltage conversion unit. [Figure 6] FIG. 6 is a configuration diagram of the second voltage conversion unit. [Figure 7] FIG. 7 is a flowchart of the process performed by the control unit of the first embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Description of the embodiments of the present disclosure] In the following, embodiments of the present disclosure are listed and illustrated.

[0012] [1] An on-board power control device mounted on a vehicle having a solar cell unit, a low-voltage battery, and a high-voltage battery, a power adjustment unit that performs an adjustment operation of adjusting the power input from the solar cell unit and outputting the adjusted power to the conductive path; a first voltage conversion unit that is provided between the conductive path and the low-voltage battery and performs a conversion operation of converting a voltage input from the conductive path side and outputting the converted voltage to the low-voltage battery side; a second voltage conversion unit provided between the low-voltage battery and the high-voltage battery, for performing a boost operation of boosting an input voltage and outputting the boosted voltage to the high-voltage battery; a control unit that controls the power adjustment unit, the first voltage conversion unit, and the second voltage conversion unit, The control unit charges the low-voltage battery by causing the power adjustment unit to perform the adjustment operation and the first voltage conversion unit to perform the conversion operation while the second voltage conversion unit is stopped, and then charges the high-voltage battery with power from the low-voltage battery by causing the second voltage conversion unit to perform the voltage step-up operation while the power adjustment unit is stopped. Automotive power control device.

[0013] The in-vehicle power control device temporarily charges the low-voltage battery with power supplied from the solar cell unit, and then charges the high-voltage battery with power from the low-voltage battery. This allows the in-vehicle power control device to charge the high-voltage battery with power from the solar cell unit with high conversion efficiency without providing a power storage unit between the power adjustment unit and the second voltage conversion unit. Furthermore, because the in-vehicle power control device does not provide a power storage unit, it is easy to save space.

[0014] [2] The vehicle is equipped with a battery monitoring device that monitors the voltage of the high-voltage battery, the second voltage conversion unit is provided between the conductive path and the high-voltage battery, and performs the voltage boosting operation to boost a voltage input from the conductive path side and output the boosted voltage to the high-voltage battery side; When the control unit receives an enabling signal output by the battery monitoring device when it determines that the high-voltage battery is in a state where it can be charged, the control unit causes the power adjustment unit to perform the adjustment operation and the second voltage conversion unit to perform the boost operation, thereby charging the high-voltage battery. The in-vehicle power control device according to [1].

[0015] The above-described in-vehicle power control device can directly charge the high-voltage battery from the solar cell unit when the control unit receives an enabling signal from the battery monitoring device.

[0016] [3] When the control unit receives the permission signal, the control unit determines a distribution ratio for supplying the power supplied from the solar cell unit to the low-voltage battery and the high-voltage battery based on a difference or ratio between a pre-stored first reference value and the voltage of the low-voltage battery and a difference or ratio between a pre-stored second reference value and the voltage of the high-voltage battery, and controls the first voltage conversion unit and the second voltage conversion unit based on the determined distribution ratio. The in-vehicle power control device according to [2].

[0017] The above-described on-vehicle power control device can charge the low-voltage battery and the high-voltage battery at a distribution ratio according to the charge states of the batteries.

[0018] [4] When the control unit receives the permission signal, the control unit determines whether the power supplied from the solar cell unit should be supplied to the low-voltage battery or the high-voltage battery based on a difference or ratio between a pre-stored first reference value and the voltage of the low-voltage battery and a difference or ratio between a pre-stored second reference value and the voltage of the high-voltage battery, and controls the first voltage conversion unit and the second voltage conversion unit so that the power is supplied to the battery determined as the supply destination. The in-vehicle power control device according to [2] or [3].

[0019] The above-described on-vehicle power control device can selectively charge either the low-voltage battery or the high-voltage battery depending on the charge state of the two batteries.

[0020] [5] The control unit causes the power adjustment unit to perform the adjustment operation by performing PWM control at a first on-duty on a first switch included in the power adjustment unit, and causes the first voltage conversion unit to perform the conversion operation by performing PWM control at a second on-duty on a second switch included in the first voltage conversion unit; The cycle for switching the second on-duty is the same as the cycle for switching the first on-duty, or is shorter than the cycle for switching the first on-duty. The vehicle-mounted power control device according to any one of [1] to [4].

[0021] In the above-described in-vehicle power control device, the cycle for switching the second on-duty is the same as or shorter than the cycle for switching the first on-duty, which makes it easier to adapt the conversion operation by the first voltage conversion unit to changes in the output voltage of the power adjustment unit.

[0022] [6] The control unit causes the power adjustment unit to perform the adjustment operation by performing PWM control at a first on-duty on a first switch included in the power adjustment unit, causes the first voltage conversion unit to perform the conversion operation by performing PWM control at a second on-duty on a second switch included in the first voltage conversion unit, and causes the second voltage conversion unit to perform the boost operation by performing PWM control at a third on-duty on a third switch included in the second voltage conversion unit, The cycle for switching the second on-duty and the cycle for switching the third on-duty are the same as the cycle for switching the first on-duty or shorter than the cycle for switching the first on-duty. The vehicle-mounted power control device according to any one of [2] to [4].

[0023] In the above-described in-vehicle power control device, the cycle for switching the second on-duty is the same as or shorter than the cycle for switching the first on-duty. This makes it easy to adapt the conversion operation by the first voltage conversion unit to changes in the output voltage of the power adjustment unit. Also, the cycle for switching the third on-duty is the same as or shorter than the cycle for switching the first on-duty. This makes it easy to adapt the boost operation by the second voltage conversion unit to changes in the output voltage of the power adjustment unit when power from the power adjustment unit is directly charged to the high-voltage battery.

[0024] [7] The control unit causes the first voltage conversion unit to start the conversion operation within ±1 ms after causing the power adjustment unit to start the adjustment operation. The vehicle-mounted power control device according to any one of [1] to [6].

[0025] According to this configuration, it is easy to link the start timing of the conversion operation by the first voltage conversion unit with the start timing of the adjustment operation by the power adjustment unit.

[0026] [8] When the control unit receives the permission signal, the control unit causes the second voltage conversion unit to start the voltage step-up operation within ±1 ms after causing the power adjustment unit to start the adjustment operation. An on-board power control device according to any one of [2] to [4], [7], and [5] [6] that directly or indirectly cites [2].

[0027] According to this configuration, when the high-voltage battery is directly charged with power from the power adjustment unit, the start timing of the conversion operation by the second voltage conversion unit can be easily linked to the start timing of the adjustment operation by the power adjustment unit.

[0028] [9] The cycle of switching the second on-duty and the cycle of switching the third on-duty are within 100 ms. [6], and an on-board power control device according to either [7] or [8] that directly or indirectly cites [6].

[0029] According to this configuration, the second on-duty and the third on-duty can be switched in a short cycle of 100 ms or less.

[0030]

[10] The cycle for switching the first on-duty is within 1 second. An on-board power control device according to any one of [5], [6], [7] [8] which directly or indirectly cites [5], and [7] [8] which directly or indirectly cites [6].

[0031] According to this configuration, the first on-duty can be switched in a short cycle of less than one second.

[0032]

[11] The cycle for switching the first on-duty is within 100 ms. The in-vehicle power control device according to

[10] .

[0033] According to this configuration, the first on-duty can be switched in a short cycle of 100 ms or less.

[0034] [Details of the embodiments of the present disclosure] 1. First embodiment 1-1. Vehicle 1 configuration 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, a low-voltage battery 3, a high-voltage battery 4, and a battery monitoring device 5.

[0035] 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.

[0036] The low-voltage battery 3 is, for example, a lead battery, and the fully charged voltage of the low-voltage battery 3 is, for example, 12V, 24V, or 48V.

[0037] The high-voltage battery 4 is, for example, a lithium-ion battery. The full charge voltage of the high-voltage battery 4 is higher than the full charge voltage of the low-voltage battery 3, and is, for example, 400V or 800V.

[0038] The battery monitoring device 5 is a device that manages information such as the voltage of the high-voltage battery 4. The battery monitoring device 5 has functions such as preventing overcharging and over-discharging of the cells that make up the high-voltage battery 4, preventing overcurrent in the cells, managing the cell temperature, calculating the remaining battery capacity, and equalizing the cell voltages (cell balancing). The battery monitoring device 5 outputs a permission signal when it determines that the high-voltage battery 4 is in a state where it can be charged. The battery monitoring device 5 determines whether the high-voltage battery 4 is in a state where it can be charged, for example, based on the charging voltage of the high-voltage battery 4. The battery monitoring device 5 determines that the high-voltage battery 4 is in a state where it can be charged, for example, when the charging voltage of the high-voltage battery 4 is equal to or lower than a predetermined upper chargeable limit. The battery monitoring device 5 is, for example, a battery management system.

[0039] 1-2. Configuration of the in-vehicle power control device 10 The vehicle power control device 10 mounted on the vehicle 1 includes a power adjustment unit 11, a conductive path 12, a first voltage conversion unit 13, a second voltage conversion unit 14, and a control unit 15.

[0040] The power adjustment unit 11 is supplied with power output from the solar cell unit 2. The power adjustment unit 11 performs an adjustment operation of adjusting the power input from the solar cell unit 2 and outputting it to the conductive path 12. The power adjustment unit 11 operates in accordance with the MPPT (Maximum Power Point Tracking) method under the control of the control unit 15. The power adjustment unit 11 is configured, for example, by a DC-DC converter.

[0041] The first voltage conversion unit 13 is provided between the conduction path 12 and the low-voltage battery 3. The first voltage conversion unit 13 performs a first conversion operation of stepping up or stepping down the voltage input from the conduction path 12 side and outputting it to the low-voltage battery 3 side. The first conversion operation corresponds to an example of a conversion operation. The first voltage conversion unit 13 performs a second conversion operation of stepping up or stepping down the voltage input from the low-voltage battery 3 side and outputting it to the conduction path 12 side. The first voltage conversion unit 13 is configured by, for example, a DC-DC converter.

[0042] The second voltage conversion unit 14 is provided between the conductive path 12 and the high-voltage battery 4. That is, the second voltage conversion unit 14 is provided between the low-voltage battery 3, the first voltage conversion unit 13, the conductive path 12, and the high-voltage battery 4. The second voltage conversion unit 14 performs a boost operation to boost the voltage input from the conductive path 12 side and output it to the high-voltage battery 4 side. Specifically, in the boost operation, the second voltage conversion unit 14 boosts the voltage output from the first voltage conversion unit 13, which performs the second conversion operation, and outputs it to the high-voltage battery 4 side. The second voltage conversion unit 14 is configured by, for example, a DC-DC converter.

[0043] The control unit 15 is configured to include, for example, a microcomputer. The control unit 15 causes the power adjustment unit 11 to perform an adjustment operation so as to maximize the output power. The control unit 15 causes the first voltage conversion unit 13 to perform a first conversion operation so as to make the output voltage a first target voltage. The control unit 15 causes the first voltage conversion unit 13 to perform a second conversion operation so as to make the output voltage a second target voltage. The control unit 15 causes the second voltage conversion unit 14 to perform a boost operation so as to make the output voltage a boost target voltage.

[0044] 2, the control unit 15 charges the low-voltage battery 3 by causing the power adjustment unit 11 to perform an adjustment operation and the first voltage conversion unit 13 to perform a first conversion operation while the second voltage conversion unit 14 is stopped. After charging the low-voltage battery 3, the control unit 15 causes the first voltage conversion unit 13 to perform a second conversion operation and the second voltage conversion unit 14 to perform a boost operation while the power adjustment unit 11 is stopped.

[0045] As a result, the second target voltage output from the first voltage conversion unit 13 is applied to the conductive path 12, and the second target voltage applied to the conductive path 12 is boosted by the second voltage conversion unit 14. Then, the voltage boosted by the second voltage conversion unit 14 is supplied to the high-voltage battery 4.

[0046] With this configuration, the second voltage conversion unit 14 performs a boost operation based on the stable voltage applied to the conductive path 12, thereby improving conversion efficiency compared to a case where the boost operation is performed based on the output voltage from the solar cell unit 2, which has a wide fluctuation range. In other words, the in-vehicle power control device 10 can charge the high-voltage battery 4 based on the power from the solar cell unit 2 with high conversion efficiency, without providing a power storage unit between the power adjustment unit 11 and the second voltage conversion unit 14. Furthermore, since the in-vehicle power control device 10 does not have a power storage unit, it is easy to achieve space savings.

[0047] It should be noted that "after the low-voltage battery 3 has been charged" is not limited to "after the low-voltage battery 3 has reached a full charge voltage" but may be "after the low-voltage battery 3 has been charged even a little."

[0048] Furthermore, when the control unit 15 receives the above-mentioned permission signal from the battery monitoring device 5, it causes the power adjustment unit 11 to perform an adjustment operation and the second voltage conversion unit 14 to perform a voltage boosting operation, thereby charging the high-voltage battery 4. In other words, as shown in Fig. 3, when the control unit 15 receives a permission signal from the battery monitoring device 5, the in-vehicle power control device 10 can directly charge the high-voltage battery 4 from the solar cell unit 2.

[0049] When the in-vehicle power control device 10 directly charges the high-voltage battery 4 from the solar cell unit 2, it may also charge the low-voltage battery 3 in parallel. For example, when the control unit 15 receives an enabling signal, it may determine a distribution ratio for supplying power from the solar cell unit 2 to the low-voltage battery 3 and the high-voltage battery 4, and control the first voltage conversion unit 13 and the second voltage conversion unit 14 based on the determined distribution ratio. In other words, the control unit 15 may control the first voltage conversion unit 13 and the second voltage conversion unit 14 so that power is distributed to the low-voltage battery 3 and the high-voltage battery 4 at the determined distribution ratio. With this configuration, the in-vehicle power control device 10 can charge the low-voltage battery 3 and the high-voltage battery 4 at a distribution ratio that corresponds to their respective states of charge.

[0050] The control unit 15 may determine the distribution ratio based on the difference between a pre-stored first reference value and the voltage of the low-voltage battery 3 and the difference between a pre-stored second reference value and the voltage of the high-voltage battery 4. The control unit 15 may determine the distribution ratio based on the ratio between a pre-stored first reference value and the voltage of the low-voltage battery 3 and the ratio between a pre-stored second reference value and the voltage of the high-voltage battery 4. The ratio between the first reference value and the voltage of the low-voltage battery 3 is, for example, the ratio of the voltage of the low-voltage battery 3 to the first reference value (hereinafter also referred to as the first ratio). The ratio between the second reference value and the voltage of the high-voltage battery 4 is, for example, the ratio of the voltage of the high-voltage battery 4 to the second reference value (hereinafter also referred to as the second ratio). The first reference value is, for example, the full charge voltage of the low-voltage battery 3 in an initial state. The second reference value is, for example, the full charge voltage of the high-voltage battery 4 in an initial state.

[0051] When the first ratio and the second ratio are the same, the distribution ratio of power supplied to the low-voltage battery 3 and the high-voltage battery 4 is, for example, the ratio between the first reference value and the second reference value. When the first ratio is smaller than the second ratio, the ratio supplied to the low-voltage battery 3 increases. Conversely, when the second ratio is smaller than the first ratio, the ratio supplied to the high-voltage battery 4 increases.

[0052] The control unit 15 may acquire the information indicating the voltage of the low-voltage battery 3 and the information indicating the voltage of the high-voltage battery 4 from the battery monitoring device 5, or may acquire the information without going through the battery monitoring device 5.

[0053] Furthermore, the in-vehicle power control device 10 may not charge the high-voltage battery 4 from the solar cell unit 2 even when the control unit 15 receives an enabling signal. For example, when the control unit 15 receives an enabling signal, the control unit 15 may determine whether the power from the solar cell unit 2 is to be supplied to the low-voltage battery 3 or the high-voltage battery 4, and control the first voltage conversion unit 13 and the second voltage conversion unit 14 so that the power is supplied to the determined battery. That is, when the control unit 15 determines to supply power to the low-voltage battery 3, the control unit 15 may charge the low-voltage battery 3 by causing the power adjustment unit 11 to perform an adjustment operation and the first voltage conversion unit 13 to perform a first conversion operation while stopping the second voltage conversion unit 14. When the control unit 15 determines to supply power to the high-voltage battery 4, the control unit 15 may charge the high-voltage battery 4 by causing the power adjustment unit 11 to perform an adjustment operation and the second voltage conversion unit 14 to perform a voltage step-up operation while stopping the first voltage conversion unit 13. According to this configuration, the in-vehicle power control device 10 can selectively charge either the low-voltage battery 3 or the high-voltage battery 4 depending on the state of charge of each battery.

[0054] The control unit 15 may determine the supply destination based on the difference between a pre-stored first reference value and the voltage of the low-voltage battery 3, and the difference between a pre-stored second reference value and the voltage of the high-voltage battery 4. The control unit 15 may determine the supply destination based on the ratio between a pre-stored first reference value and the voltage of the low-voltage battery 3, and the ratio between a pre-stored second reference value and the voltage of the high-voltage battery 4. For example, the control unit 15 may determine the low-voltage battery 3 as the supply destination when the first ratio is smaller than the second ratio, and may determine the high-voltage battery 4 as the supply destination when the second ratio is smaller than the first ratio.

[0055] 1-3. Specific Examples of the Power Adjustment Unit 11, the First Voltage Conversion Unit 13, and the Second Voltage Conversion Unit 14 The power adjustment unit 11 is configured by, for example, a step-down chopper circuit shown in Fig. 4. The power adjustment unit 11 has switches 21 and 22, an inductor 23, and capacitors 24 and 25.

[0056] Switches 21 and 22 are connected in series between ground 80 and input-side conductive path 81. Input-side conductive path 81 is an electrical path that supplies the output current of solar cell unit 2 to power adjustment unit 11. Switch 21 is a high-side switch. Switch 22 is a low-side switch. One end of inductor 23 is connected to the connection point between switches 21 and 22. The other end of inductor 23 is connected to conductive path 12. Capacitor 24 is an input capacitor provided on the input side of power adjustment unit 11. Capacitor 25 is an output capacitor provided on the output side of power adjustment unit 11.

[0057] Control unit 15 causes power adjustment unit 11 to perform an adjustment operation by performing PWM control on switch 21 at a first on-duty. When controlling switch 21 with PWM, control unit 15 switches the on / off states of switches 21 and 22 in a complementary manner. Control unit 15 adjusts the output power of power adjustment unit 11 by adjusting the first on-duty. Switch 21 corresponds to an example of a first switch.

[0058] The first voltage conversion unit 13 is configured by, for example, an H-bridge type DC-DC converter shown in Fig. 5. The first voltage conversion unit 13 has switches 31, 32, 33, and 34, an inductor 35, and capacitors 36 and 37.

[0059] Switches 31 and 32 are connected in series between ground 80 and the conductive path 12. Switch 31 is a high-side switch. Switch 32 is a low-side switch. Switches 33 and 34 are connected in series between ground 80 and a low-voltage battery side conductive path 82. The low-voltage battery side conductive path 82 is an electrical path that allows current to flow from the first voltage conversion unit 13 to the low-voltage battery 3 and from the low-voltage battery 3 to the first voltage conversion unit 13. Switch 33 is a high-side switch. Switch 34 is a low-side switch.

[0060] One end of inductor 35 is connected to the connection between switch 31 and switch 32. The other end of inductor 35 is connected to the connection between switch 33 and switch 34. Capacitor 36 is an input capacitor provided on the input side of first voltage conversion unit 13. Capacitor 36 is connected between ground 80 and conductive path 12. Capacitor 37 is an output capacitor provided on the output side of first voltage conversion unit 13. Capacitor 37 is connected between ground 80 and low-voltage battery-side conductive path 82.

[0061] As described above, the control unit 15 performs the first conversion operation of stepping up or stepping down the voltage input from the conductive path 12 side and outputting it to the low-voltage battery 3 side.

[0062] When boosting the voltage input from the conductive path 12 side and outputting it to the low-voltage battery 3 side, the control unit 15 controls the switch 31 to the on state and the switch 32 to the off state, and performs PWM control on the switch 34 at a predetermined on-duty. The on-duty at this time corresponds to an example of a second on-duty. The switch 34 corresponds to an example of a second switch. When performing PWM control on the switch 34, the control unit 15 switches the on / off states of the switches 33 and 34 complementarily.

[0063] When stepping down the voltage input from the conductive path 12 side and outputting it to the low-voltage battery 3 side, the control unit 15 controls the switch 33 to the on state and the switch 34 to the off state, and performs PWM control on the switch 31 at a predetermined on-duty. The on-duty at this time corresponds to an example of a second on-duty. The switch 31 corresponds to an example of a second switch. When performing PWM control on the switch 31, the control unit 15 switches the on / off states of the switches 31 and 32 complementarily.

[0064] As described above, the control unit 15 performs the second conversion operation of stepping up or stepping down the voltage input from the low-voltage battery 3 side and outputting it to the conductive path 12 side.

[0065] When boosting the voltage input from the low-voltage battery 3 and outputting it to the conductive path 12, the control unit 15 controls the switch 33 to the on state and the switch 34 to the off state, thereby performing PWM control on the switch 32 with a predetermined on-duty. When performing PWM control on the switch 32, the control unit 15 switches the on / off states of the switches 31 and 32 complementarily.

[0066] When stepping down the voltage input from the low-voltage battery 3 and outputting it to the conductive path 12, the control unit 15 controls the switch 31 to the on state, controls the switch 32 to the off state, and performs PWM control with a predetermined on-duty on the switch 33. When performing PWM control on the switch 33, the control unit 15 switches the on / off states of the switches 33 and 34 complementarily.

[0067] The second voltage conversion unit 14 is configured by, for example, an insulating DC-DC converter shown in Fig. 6. The second voltage conversion unit 14 has switches 41, 42, 43, 44, 45, 46, 47, and 48, a transformer 50, inductors 51 and 52, and capacitors 53 and 54.

[0068] The switches 41, 42, 43, and 44 form a full bridge circuit on the input side. The switches 41 and 42 are connected in series between the conductive path 12 and ground 80. The switches 43 and 44 are connected in series between the conductive path 12 and ground 80 and are connected in parallel to the switches 41 and 42.

[0069] The switches 45, 46, 47, and 48 form a full-bridge circuit on the output side. The switches 45 and 46 are connected in series between the high-potential side conductive path 83 and the low-potential side conductive path 84. The switches 47 and 48 are connected in series between the high-potential side conductive path 83 and the low-potential side conductive path 84, and are connected in parallel to the switches 45 and 46.

[0070] The transformer 50 has a first winding 55 and a second winding 56. The first winding 55 and the second winding 56 are magnetically coupled to each other. The number of turns of the second winding 56 is greater than the number of turns of the first winding 55.

[0071] Switch 41 and switch 42 are connected at connection point C1. Switch 43 and switch 44 are connected at connection point C2. First winding 55 and inductor 51 are connected in series between connection points C1 and C2.

[0072] Switch 45 and switch 46 are connected at connection C3. Switch 47 and switch 48 are connected at connection C4. Second winding 56 and inductor 52 are connected in series between connection C3 and connection C4.

[0073] Capacitor 53 is an input capacitor provided on the input side of second voltage conversion unit 14. Capacitor 53 is connected between conductive path 12 and ground 80. Capacitor 54 is an output capacitor provided on the output side of second voltage conversion unit 14. Capacitor 53 is connected between high potential side conductive path 83 and low potential side conductive path 84.

[0074] As described above, second voltage conversion unit 14 performs a boost operation of boosting the voltage input from conductive path 12 and outputting the boosted voltage to high-voltage battery 4. Control unit 15 complementarily switches the on / off states of switches 41, 44 and switches 42, 43, and performs PWM control of switches 41, 42, 43, 44 with a third on-duty, thereby causing second voltage conversion unit 14 to perform a boost operation. Switches 41, 42, 43, 44 correspond to an example of a third switch.

[0075] As described above, second voltage conversion unit 14 performs a step-down operation of stepping up the voltage input from high-voltage battery 4 and outputting the voltage to conductive path 12. Control unit 15 complementarily switches the on / off states of switches 45, 48 and switches 46, 47, and performs PWM control on switches 45, 46, 47, 48 with a predetermined on-duty, thereby causing second voltage conversion unit 14 to perform a step-down operation.

[0076] The cycle for switching the second on-duty is preferably the same as or shorter than the cycle for switching the first on-duty. For example, the control unit 15 performs a first process for switching the first on-duty every first cycle, and a second process for switching the second on-duty every second cycle. The second cycle is preferably the same as or shorter than the first cycle. This configuration makes it easier to adapt the conversion operation by the first voltage conversion unit 13 to changes in the output voltage of the power adjustment unit 11. The first cycle is preferably within 1 second, and more preferably within 100 ms. The second cycle is preferably within 100 ms.

[0077] The cycle for switching the third on-duty is preferably the same as or shorter than the cycle for switching the first on-duty. The control unit 15 performs, for example, the third process of switching the third on-duty every third cycle. The third cycle is preferably the same as or shorter than the first cycle. This configuration makes it easier to adapt the boost operation by the second voltage conversion unit 14 to changes in the output voltage of the power adjustment unit 11 when the high-voltage battery 4 is directly charged with power from the power adjustment unit 11. The third cycle is preferably within 100 ms.

[0078] The cycle for switching the third on-duty may be the same as or different from the cycle for switching the second on-duty. From the viewpoint of reducing the control burden on the second voltage conversion unit 14 and the load on the high-voltage battery 4, it is preferable that the cycle for switching the third on-duty be shorter than the cycle for switching the second on-duty.

[0079] For example, control unit 15 causes first voltage conversion unit 13 to start a conversion operation within ±1 ms after causing power adjustment unit 11 to start an adjustment operation. With this configuration, it is easy to link the start timing of the conversion operation by first voltage conversion unit 13 to the start timing of the adjustment operation by power adjustment unit 11.

[0080] For example, when control unit 15 receives an enabling signal, it causes second voltage conversion unit 14 to start a boost operation within ±1 ms of causing power adjustment unit 11 to start an adjustment operation. With this configuration, when power from power adjustment unit 11 is directly charged to high-voltage battery 4, it is easy to link the start timing of the conversion operation by second voltage conversion unit 14 to the start timing of the adjustment operation by power adjustment unit 11.

[0081] The control unit 15 performs the process shown in FIG. 7, for example. The control unit 15 sets the counter value stored therein to 0 (step S10), then performs the second process described above (step S11), and performs the third process described above (step S12). The control unit 15 then determines whether a predetermined time has elapsed (step S13). The control unit 15 repeats the process of step S13 until the predetermined time has elapsed. If the control unit 15 determines that the predetermined time has elapsed (Yes in step S13), it increments the counter by 1 (step S14) and determines whether the counter value has reached N (step S15), where N is a natural number equal to or greater than 2. If the control unit 15 determines that the counter value is not N (No in step S15), it returns to the process of step S11. If the control unit 15 determines that the counter value is N (Yes in step S15), it resets the counter value (step S16), performs the first process (step S17), and returns to the process of step S11.

[0082] That is, the control unit 15 performs the second process and the third process every time a predetermined time elapses, and performs the first process every time a time N times the predetermined time elapses.

[0083] In the first process, the control unit 15 determines whether a condition for starting an adjustment operation by the power adjustment unit 11 is met. The condition for starting the adjustment operation is, for example, that the power generated by the solar cell unit 2 exceeds a threshold. When the control unit 15 determines that the condition for starting the adjustment operation is met, the control unit 15 causes the power adjustment unit 11 to start the adjustment operation. The control unit 15 sets a first on-duty so that the output power of the power adjustment unit 11 is maximized, and performs PWM control on the switch 21 of the power adjustment unit 11 at the set first on-duty. When the control unit 15 starts the first process and the power adjustment unit 11 is already performing an adjustment operation, the control unit 15 determines whether to continue the adjustment operation. For example, the control unit 15 determines to continue the adjustment operation when the power generated by the solar cell unit 2 exceeds a threshold. When the control unit 15 determines to continue the adjustment operation, the control unit 15 resets the first on-duty so that the output power of the power adjustment unit 11 is maximized, and performs PWM control on the switch 21 of the power adjustment unit 11 at the reset first on-duty. When it is determined that the adjustment operation should not be continued, control unit 15 stops the adjustment operation by power adjustment unit 11. In this way, control unit 15 switches the first on-duty every N times the predetermined time (i.e., every first period).

[0084] In the second process, the control unit 15 determines whether a condition for starting the first conversion operation by the first voltage conversion unit 13 is satisfied. The condition for starting the first conversion operation is, for example, when the power generated by the solar cell unit 2 exceeds a threshold. When the control unit 15 determines that the condition for starting the first conversion operation is satisfied, the control unit 15 causes the first voltage conversion unit 13 to start the first conversion operation. However, the control unit 15 does not cause the first voltage conversion unit 13 to start the first conversion operation while receiving an enable signal. The control unit 15 sets a second on-duty based on the voltage of the conductive path 12 and performs PWM control on the switches 31 and 34 of the first voltage conversion unit 13 at the set second on-duty. When starting the second process, if the first voltage conversion unit 13 is already performing the first conversion operation, the control unit 15 determines whether to continue the first conversion operation. For example, the control unit 15 determines to continue the first conversion operation when the power generated by the solar cell unit 2 exceeds a threshold and an enable signal has not been received. When control unit 15 determines to continue the first conversion operation, it resets the second on-duty based on the voltage of conduction path 12 and performs PWM control on switches 31, 34 of first voltage conversion unit 13 at the reset second on-duty. When control unit 15 determines not to continue the first conversion operation, it stops the first conversion operation by first voltage conversion unit 13. In this way, control unit 15 switches the second on-duty every predetermined time (i.e., every second period).

[0085] In the third process, the control unit 15 determines whether a condition for starting the boost operation by the second voltage conversion unit 14 is met. The condition for starting the boost operation is, for example, when the power generated by the solar cell unit 2 exceeds a threshold and an enabling signal is received. If the control unit 15 determines that the condition for starting the boost operation is met, the control unit 15 causes the second voltage conversion unit 14 to start the boost operation. The control unit 15 sets a third on-duty based on the voltage of the conductive path 12 and performs PWM control on the switches 41, 42, 43, and 44 of the second voltage conversion unit 14 at the set third on-duty. When the control unit 15 starts the third process, if the second voltage conversion unit 14 is already performing the boost operation, the control unit 15 determines whether to continue the boost operation. For example, if the power generated by the solar cell unit 2 exceeds a threshold and an enabling signal is received, the control unit 15 determines to continue the boost operation. When control unit 15 determines to continue the voltage boosting operation, it resets the third on-duty based on the voltage of conduction path 12 and performs PWM control on switches 41, 42, 43, and 44 of second voltage conversion unit 14 at the reset third on-duty. When control unit 15 determines not to continue the voltage boosting operation, it stops the voltage boosting operation by second voltage conversion unit 14. In this way, control unit 15 switches the third on-duty every predetermined time (i.e., every third period).

[0086] <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, the 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.

[0087] 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.

[0088] The power adjustment unit and the first voltage conversion unit may share some of the elements.

[0089] 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, but is intended to include all modifications within the scope indicated by the claims or the scope equivalent to the claims. [Explanation of symbols]

[0090] 1...Vehicle 2…Solar cell section 3...Low voltage battery 4...High voltage battery 5. Battery monitoring device 10...In-vehicle power control device 11...Power adjustment section 12...Conductive path 13...First voltage conversion unit 14...Second voltage conversion unit 15...Control unit 21...Switch (first switch) 22...Switch 23...Inductor 24...Capacitor 25...Capacitor 31...Switch (second switch) 32...Switch 33...Switch 34...Switch (second switch) 35...Inductor 36...Capacitor 37...Capacitor 41...Switch (third switch) 42...Switch (third switch) 43...Switch (third switch) 44...Switch (third switch) 45...Switch 46...Switch 47...Switch 48...Switch 50...trans 51...Inductor 52...Inductor 53...Capacitor 54...Capacitor 55...1st winding 56...Second winding 80...Grand 81...input side conductive path 82...Low voltage battery side conductive path 83...High potential side conductive path 84...Low potential side conductive path C1...Connection C2...Connection C3…Connection C4…Connection

Claims

1. An on-board power control device mounted on a vehicle including a solar cell unit, a low-voltage battery, and a high-voltage battery, a power adjustment unit that performs an adjustment operation of adjusting the power input from the solar cell unit and outputting the adjusted power to the conductive path; a first voltage conversion unit that is provided between the conductive path and the low-voltage battery and performs a conversion operation of converting a voltage input from the conductive path side and outputting the converted voltage to the low-voltage battery side; a second voltage conversion unit provided between the low-voltage battery and the high-voltage battery, for performing a boost operation of boosting an input voltage and outputting the boosted voltage to the high-voltage battery; a control unit that controls the power adjustment unit, the first voltage conversion unit, and the second voltage conversion unit, The control unit charges the low-voltage battery by causing the power adjustment unit to perform the adjustment operation and the first voltage conversion unit to perform the conversion operation while the second voltage conversion unit is stopped, and then charges the high-voltage battery with power from the low-voltage battery by causing the second voltage conversion unit to perform the voltage step-up operation while the power adjustment unit is stopped. Automotive power control device.

2. the vehicle includes a battery monitoring device that monitors the voltage of the high-voltage battery; the second voltage conversion unit is provided between the conductive path and the high-voltage battery, and performs the voltage boosting operation to boost a voltage input from the conductive path side and output the boosted voltage to the high-voltage battery side; When the control unit receives an enabling signal output by the battery monitoring device when it determines that the high-voltage battery is in a state where it can be charged, the control unit causes the power adjustment unit to perform the adjustment operation and the second voltage conversion unit to perform the boost operation, thereby charging the high-voltage battery. The vehicle-mounted power control device according to claim 1 .

3. When the control unit receives the permission signal, the control unit determines a distribution ratio for supplying the power supplied from the solar cell unit to the low-voltage battery and the high-voltage battery based on a difference or ratio between a pre-stored first reference value and the voltage of the low-voltage battery and a difference or ratio between a pre-stored second reference value and the voltage of the high-voltage battery, and controls the first voltage conversion unit and the second voltage conversion unit based on the determined distribution ratio. The vehicle-mounted power control device according to claim 2 .

4. When the control unit receives the permission signal, the control unit determines to which of the low-voltage battery and the high-voltage battery the power supplied from the solar cell unit should be supplied, based on a difference or ratio between a pre-stored first reference value and the voltage of the low-voltage battery and a difference or ratio between a pre-stored second reference value and the voltage of the high-voltage battery, and controls the first voltage conversion unit and the second voltage conversion unit so that the power is supplied to the battery determined as the supply destination. The vehicle-mounted power control device according to claim 2 .

5. the control unit causes the power adjustment unit to perform the adjustment operation by performing PWM control at a first on-duty on a first switch included in the power adjustment unit, and causes the first voltage conversion unit to perform the conversion operation by performing PWM control at a second on-duty on a second switch included in the first voltage conversion unit, The cycle for switching the second on-duty is the same as the cycle for switching the first on-duty, or is shorter than the cycle for switching the first on-duty. The on-board power control device according to any one of claims 1 to 3.

6. the control unit causes the power adjustment unit to perform the adjustment operation by performing PWM control at a first on-duty on a first switch included in the power adjustment unit, causes the first voltage conversion unit to perform the conversion operation by performing PWM control at a second on-duty on a second switch included in the first voltage conversion unit, and causes the second voltage conversion unit to perform the boost operation by performing PWM control at a third on-duty on a third switch included in the second voltage conversion unit, The cycle for switching the second on-duty and the cycle for switching the third on-duty are the same as the cycle for switching the first on-duty or shorter than the cycle for switching the first on-duty. The vehicle-mounted power control device according to claim 2 .

7. The control unit causes the first voltage conversion unit to start the conversion operation within ±1 ms after causing the power adjustment unit to start the adjustment operation. The vehicle-mounted power control device according to claim 1 .

8. When the control unit receives the permission signal, the control unit causes the second voltage conversion unit to start the voltage step-up operation within ±1 ms after causing the power adjustment unit to start the adjustment operation. The vehicle-mounted power control device according to claim 2 .

9. The cycle of switching the second on-duty and the cycle of switching the third on-duty are within 100 msec. The vehicle-mounted power control device according to claim 6.

10. The cycle of switching the first on-duty is within 1 second. The vehicle-mounted power control device according to claim 5 .

11. The cycle for switching the first on-duty is within 100 ms. The vehicle-mounted power control device according to claim 10.

Images