Power supply system

Abstract

To prevent a vehicle from becoming undrivable due to a battery voltage drop with a simple and cost-effective configuration.SOLUTION: A vehicle is mounted with an electrical component (13) and an electric motor (11). A power supply system (1) of the vehicle includes: an electrical component battery (14) which supplies electric power to the electrical component; a drive battery (12) which supplies electric power to the electric motor; a converter (16) which steps down voltage of the drive battery and outputs the voltage to the electrical component battery; and a controller (21) which controls the converter by driving the same with the electric power from the electrical component battery. When the voltage of the electrical component battery is less than normal operation voltage of the controller with a main switch (22) turned on and the voltage of the electrical component battery rises to the normal operation voltage of the controller or higher with the main switch turned off, the controller controls the converter to charge the electrical component battery using the electric power from the drive battery.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a power supply system. [Background technology]

[0002] In recent years, straddle-type vehicles powered by electric motors have been developed, and these straddle-type vehicles are equipped with an electrical equipment battery (auxiliary battery) for electrical equipment such as lighting fixtures in addition to a drive battery for the electric motor. The electrical equipment battery is charged with power from the drive battery, but because the drive battery has a higher voltage than the electrical equipment battery, the drive battery is connected to the electrical equipment battery via a DC / DC converter. The DC / DC converter then steps down the voltage of the drive battery to charge the electrical equipment battery (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-203953 Summary of the Invention [Problem to be solved by the invention]

[0004] If the vehicle is left unattended, the voltage of the electrical equipment battery will drop due to dark current and natural discharge, and when the main switch is turned on, the voltage of the electrical equipment battery will fall below the controller's normal operating voltage, preventing the vehicle from running.

[0005] The present invention has been made in view of the above points, and has an object to provide a power supply system that has a simple and inexpensive configuration and can prevent a vehicle from becoming unable to travel due to a drop in battery voltage. [Means for solving the problem]

[0006] One embodiment of the power supply system of the present invention is a power supply system for a vehicle equipped with electrical equipment and an electric motor, and comprises an electrical equipment battery that supplies power to the electrical equipment, a drive battery that supplies power to the electric motor, a converter that reduces the power of the drive battery and outputs it to the electrical equipment battery, and a controller that is driven by the power of the electrical equipment battery and controls the converter.When the voltage of the electrical equipment battery is less than the normal operating voltage of the controller when the main switch is ON, and when the voltage of the electrical equipment battery becomes equal to or greater than the normal operating voltage of the controller when the main switch is OFF, the controller controls the converter to charge the electrical equipment battery with the power of the drive battery, thereby solving the above problem. [Effects of the Invention]

[0007] According to one aspect of the present invention, when the main switch is turned on and the voltage of the electrical equipment battery is below the normal operating voltage of the controller, the vehicle becomes unable to travel. However, when the main switch is turned off and the voltage of the electrical equipment battery becomes equal to or higher than the normal operating voltage of the controller, the controller controls the converter to charge the electrical equipment battery. Therefore, the next time the main switch is turned on, the voltage of the electrical equipment battery becomes the normal operating voltage of the controller, allowing travel. There is no need to constantly monitor the electrical equipment battery, which reduces power consumption of the drive battery. There is also no need for a dedicated circuit, which reduces costs. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 2 is a wiring diagram of the power supply system according to the embodiment. [Figure 2] 1 is a flowchart of a typical charging operation of an electrical component battery. [Figure 3] 4 is a time chart of the charging operation of the electrical equipment battery in the embodiment; [Figure 4] 4 is a flowchart of the charging operation of the electrical equipment battery according to the embodiment.

[0009] A vehicle according to one embodiment of the present invention is equipped with electrical equipment and an electric motor. The vehicle's power supply system includes an electrical equipment battery that supplies power to the electrical equipment and a drive battery that supplies power to the electric motor. The drive battery's power is stepped down by a converter and output to the electrical equipment battery, and the converter is controlled by a controller using the electrical equipment battery's power. If the voltage of the electrical equipment battery is below the controller's normal operating voltage when the main switch is turned on, the vehicle will be unable to travel. However, if the voltage of the electrical equipment battery exceeds the controller's normal operating voltage when the main switch is turned off, the controller controls the converter to charge the electrical equipment battery with the drive battery's power. Therefore, the next time the main switch is turned on, the electrical equipment battery's voltage will return to the controller's normal operating voltage, allowing the vehicle to travel. This eliminates the need for constant monitoring of the electrical equipment battery, thereby reducing the drive battery's power consumption. This also eliminates the need for a dedicated circuit, thereby reducing costs. [Example]

[0010] The power supply system of the embodiment will be described below with reference to the accompanying drawings. Figure 1 is a wiring diagram of the power supply system of the embodiment. Figure 2 is a flowchart of a typical charging operation of a battery for an electrical component.

[0011] As shown in Fig. 1, the power supply system 1 includes a drive battery 12 that supplies power to an electric motor 11, and an electrical component battery 14 that supplies power to electrical components such as lighting fixtures 13. A parallel circuit consisting of an inverter 15 and a DC / DC converter 16 is connected to the drive battery 12. A main relay 17 is provided in a connection line extending from the positive terminal of the drive battery 12 to the positive input terminal of the inverter 15 and the positive input terminal of the DC / DC converter 16. A pre-charge relay 18 and a pre-charge resistor 19 are also connected in parallel to the main relay 17.

[0012] The electric motor 11 is connected to the output terminal of the inverter 15, and the electric motor 11 is controlled by the inverter 15 using power from the drive battery 12. The electrical equipment battery 14 is connected to the output terminal of the DC / DC converter 16, and the power of the drive battery 12 is stepped down to a desired voltage (12 V in this embodiment) by the DC / DC converter 16 and output to the electrical equipment battery 14. The electrical equipment battery 14 is charged with the power converted by the DC / DC converter 16. The electrical equipment battery 14 is connected to a controller 21 and electrical equipment such as lighting devices 13 via an ignition switch (main switch) 22.

[0013] The main relay 17, pre-charge relay 18, and DC / DC converter 16 are connected to the controller 21, and the controller 21 controls the main relay 17, pre-charge relay 18, and DC / DC converter 16. The controller 21 is connected to the electrical equipment battery 14 via an ignition switch 22, but in order to maintain some functions of the controller 21 even when the ignition switch 22 is OFF, power is supplied directly from the battery to the controller 21. Electrical equipment such as the lighting equipment 13 is turned ON / OFF in conjunction with the ON / OFF of the ignition switch 22.

[0014] 1 and 2, when the ignition switch 22 is turned ON (step S01), the controller 21 is activated by power from the electrical equipment battery 14 (step S02). When the controller 21 is activated, a control signal is output from the controller 21 to the pre-charge relay 18, causing the pre-charge relay 18 to close (step S03). As a result, power is supplied from the driving battery 12 to the inverter 15 via the pre-charge relay 18 and pre-charge resistor 19, and the inverter 15 begins to pre-charge while the inrush current is limited via the pre-charge resistor 19.

[0015] When precharging of inverter 15 is completed (Yes in step S04), controller 21 outputs a control signal to main relay 17 to close main relay 17 (step S05). Power is supplied from driving battery 12 to DC / DC converter 16, and controller 21 outputs a control signal to DC / DC converter 16 to drive DC / DC converter 16 (step S06). The voltage of driving battery 12 is stepped down by DC / DC converter 16, and charging of electrical equipment battery 14 begins via DC / DC converter 16 (step S07).

[0016] The controller 21 is set with a startup voltage required for startup and a normal operating voltage at which all functions are available, and operates in normal mode or power-saving mode depending on the voltage of the electrical equipment battery 14. When the voltage of the electrical equipment battery 14 is equal to or higher than the normal operating voltage, the controller 21 enters normal mode, performs startup processing for the vehicle system, and enables driving. When the voltage of the electrical equipment battery 14 is equal to or higher than the startup voltage but lower than the normal operating voltage, the controller 21 enters power-saving mode, allowing functions with low power consumption to be used, but not functions with high power consumption such as relay drive and startup processing for the vehicle system.

[0017] If the vehicle has been left unused for a long period of time, the battery voltage drops due to dark current from the vehicle load and natural discharge of the electrical equipment battery 14. When the ignition is on and the voltage of the electrical equipment battery 14 is equal to or greater than the startup voltage but less than the normal operating voltage, the controller 21 enters a power-saving mode and is unable to drive the relays, which consume a lot of power. As a result, the main relay 17 and pre-charge relay 18 are not closed, and the electrical equipment battery 14 cannot be charged using power from the drive battery 12 via the DC / DC converter 16. Furthermore, in the power-saving mode, the controller 21 is unable to perform startup processing for the vehicle system, making it impossible to drive the vehicle.

[0018] The voltage of the electrical component battery 14 varies depending on the load of the vehicle's electrical components. For example, the electrical component that places the greatest load on the electrical component battery 14 is the lighting equipment 13, and when the lighting equipment 13 is turned on, the voltage of the electrical component battery 14 drops significantly. As described above, the on / off state of the electrical components is linked to the on / off state of the ignition switch 22. Therefore, when the ignition is turned on, the lighting equipment 13 turns on, causing the voltage of the electrical component battery 14 to be below its normal operating voltage. However, when the ignition is turned off and the lighting equipment 13 is turned off, the voltage of the electrical component battery 14 may recover to or exceed its normal operating voltage.

[0019] Therefore, in this embodiment, if the voltage of the electrical equipment battery 14 recovers to or above the normal operating voltage when the ignition is turned off, the controller 21 drives the relay and DC / DC converter 16 to charge the electrical equipment battery 14. As a result, even if the lights 13 are turned on the next time the ignition is turned on, the voltage of the electrical equipment battery 14 will be above the normal operating voltage, making it possible to drive the vehicle. Also, the controller 21 monitors the electrical equipment battery 14 only when the ignition is on / off, thereby reducing battery power consumption and reducing costs by utilizing an existing system.

[0020] Charging control of the electrical component battery will be described with reference to Figures 3 and 4. Figure 3 is a time chart of the charging operation of the electrical component battery in this embodiment. Figure 4 is a flowchart of the charging operation of the electrical component battery in this embodiment. In the following explanation, the symbols in Figure 1 will be used as appropriate. Furthermore, the following time charts and flowcharts are merely examples and can be modified as appropriate.

[0021] As shown in Figure 3, when the ignition switch 22 is OFF, the voltage of the electrical component battery 14 is equal to or higher than the normal operating voltage V1. When the ignition switch 22 is turned ON at time t1, the lighting devices 13 are turned on in conjunction with the ignition switch 22 being turned ON. Current is supplied from the electrical component battery 14 to the lighting devices 13 and the controller 21, and the voltage of the electrical component battery 14 becomes lower than the normal operating voltage V1 and higher than the starting voltage V2 due to the current consumption of the lighting devices 13 and the controller 21. Because the controller 21 operates in power saving mode, it is not possible to charge the electrical component battery 14 or to drive the vehicle.

[0022] When the ignition switch 22 is turned OFF at time t2, the lighting devices 13 are turned off in conjunction with the ignition switch 22 being turned OFF. No current is supplied from the electrical equipment battery 14 to the lighting devices 13, and only the current consumed by the controller 21 remains, causing the voltage of the electrical equipment battery 14 to exceed the normal operating voltage V1. The controller 21 switches from the power saving mode to the normal mode, and the pre-charge relay 18 is closed by the controller 21. The inrush current is suppressed by the pre-charge resistor 19, and the inverter 15 is pre-charged by the power from the drive battery 12 until a predetermined time has elapsed.

[0023] At time t3, controller 21 closes main relay 17 and drives DC / DC converter 16. DC / DC converter 16 steps down the voltage of drive battery 12, and current is supplied from drive battery 12 to electrical component battery 14 via DC / DC converter 16. This sufficiently boosts the voltage of electrical component battery 14, so that even if ignition switch 22 is turned ON again, the voltage of electrical component battery 14 will be equal to or higher than normal operating voltage V1. Because controller 21 operates in normal mode, the vehicle systems can be started and the vehicle can be driven.

[0024] As shown in Fig. 4, when the ignition switch 22 is turned on (step S11), the lighting devices 13 are turned on by the power of the electrical component battery 14 (step S12). The controller 21 is also activated by the power of the electrical component battery 14 (step S13). The controller 21 monitors the voltage V of the electrical component battery 14 and determines whether the voltage V of the electrical component battery 14 is equal to or higher than the normal operating voltage V1 (step S14). If the voltage V of the electrical component battery 14 is lower than the normal operating voltage V1 (No in step S14), the electrical component battery 14 experiences a voltage drop abnormality, making the vehicle unable to travel (step S15).

[0025] On the other hand, if the voltage of the electrical component battery 14 is equal to or higher than the normal operating voltage (Yes in step S14), the controller 21 determines whether the DC / DC converter 16 is operating (step S16). If the DC / DC converter 16 is stopped (No in step S16), the controller 21 closes the relays 17 and 18 in order, and then operates the DC / DC converter 16 (step S17). Then, the voltage of the driving battery 12 is stepped down by the DC / DC converter 16, and charging of the electrical component battery 14 begins via the DC / DC converter 16 (step S18).

[0026] Next, when the ignition switch 22 is turned OFF (step S19), the power supply to the electrical component battery 14 is stopped and the lighting devices 13 are turned off (step S20). In response to the turning off of the lighting devices 13, the voltage of the electrical component battery 14 is increased, and the controller 21 determines whether the voltage V of the electrical component battery 14 is equal to or higher than the normal operating voltage V1 (step S21). If the voltage V of the electrical component battery 14 is lower than the normal operating voltage V1 (No in step S21), the functions of the controller 21 are limited and the electrical component battery 14 cannot be charged, so the system is shut down (step S22).

[0027] On the other hand, if the voltage V of the electrical component battery 14 is equal to or higher than the normal operating voltage V1 (Yes in step S21), the controller 21 closes the relays 17, 18 in sequence, and then drives the DC / DC converter 16 (step S23). The voltage of the drive battery 12 is then stepped down by the DC / DC converter 16, and charging of the electrical component battery 14 begins via the DC / DC converter 16 (step S24). As a result, even if the ignition switch 22 is turned ON again and the lighting devices 13 are turned on, the voltage V of the electrical component battery 14 is maintained at or higher than the normal operating voltage V1, allowing the vehicle to travel.

[0028] In step S24, the controller 21 may control the DC / DC converter 16 to stop charging the electrical component battery 14 after a certain time has elapsed since the start of charging. By charging the electrical component battery 14 for only a certain time, deterioration of the electrical component battery 14 due to overcharging can be suppressed.

[0029] As described above, according to the power supply system 1 of this embodiment, when the lighting devices 13 are turned on in conjunction with the ignition switch 22 being turned on, if the voltage of the electrical component battery 14 falls below the normal operating voltage, the vehicle will be unable to travel. Even in this case, if the lighting devices 13 are turned off in conjunction with the ignition switch 22 being turned off and the voltage of the electrical component battery 14 rises above the normal operating voltage, the controller 21 controls the DC / DC converter 16 to charge the electrical component battery 14. Therefore, even if the lighting devices 13 are turned on in conjunction with the next turning on of the ignition switch 22, the voltage of the electrical component battery 14 will rise above the normal operating voltage, allowing travel. There is no need to constantly monitor the electrical component battery 14, which reduces power consumption of the drive battery 12. There is also no need for a dedicated circuit, which reduces costs.

[0030] The various processes of the controller may be implemented by software using a processor, or may be implemented by logic circuits (hardware) formed in an integrated circuit or the like. When a processor is used, the processor reads and executes programs stored in memory to perform various processes. For example, a CPU (Central Processing Unit) is used as the processor. The memory may be configured with one or more storage media such as ROM (Read Only Memory) and RAM (Random Access Memory) depending on the application.

[0031] Furthermore, the power supply system of this embodiment is not limited to saddle-ride vehicles, and may be used in other vehicles such as four-wheeled automobiles, etc. Note that saddle-ride vehicles are not limited to all vehicles in which the driver sits astride a seat, but also include scooter-type vehicles in which the driver does not sit astride a seat.

[0032] As described above, the first aspect is a power supply system (1) for a vehicle equipped with electrical equipment (lights 13) and an electric motor (11), and includes an electrical equipment battery (14) that supplies power to the electrical equipment, a drive battery (12) that supplies power to the electric motor, a converter (DC / DC converter 16) that reduces the power of the drive battery and outputs it to the electrical equipment battery, and a controller (21) that is driven by the power of the electrical equipment battery and controls the converter. When the voltage of the electrical equipment battery is below the normal operating voltage of the controller when the main switch (ignition switch 22) is ON, and when the voltage of the electrical equipment battery is equal to or higher than the normal operating voltage of the controller when the main switch is OFF, the controller controls the converter to charge the electrical equipment battery with power from the drive battery. With this configuration, when the main switch is ON and the voltage of the electrical equipment battery is below the normal operating voltage of the controller, the vehicle cannot travel. However, when the main switch is OFF and the voltage of the electrical equipment battery is equal to or higher than the normal operating voltage of the controller, the controller controls the converter to charge the electrical equipment battery. As a result, the next time the main switch is turned on, the voltage of the electrical equipment battery will be at the controller's normal operating voltage, allowing the vehicle to be driven. There is no need to constantly monitor the electrical equipment battery, which reduces power consumption from the drive battery. There is also no need for a dedicated circuit, which reduces costs.

[0033] In a second aspect, the controller controls the converter to stop charging the electrical component battery after a certain period of time has elapsed since the start of charging. With this configuration, the electrical component battery is charged for only a certain period of time, thereby preventing deterioration of the electrical component battery due to overcharging.

[0034] In a third aspect, in the first or second aspect, the ON / OFF of the electrical equipment is linked to the ON / OFF of the main switch. With this configuration, when the electrical equipment is turned ON in conjunction with the ON of the main switch, the voltage of the electrical equipment battery may fall below the normal operating voltage of the controller. Even in this case, when the electrical equipment is turned OFF in conjunction with the OFF of the main switch, the electrical equipment battery is charged if the voltage of the electrical equipment battery becomes equal to or higher than the normal operating voltage of the controller. Even when the electrical equipment is turned ON in conjunction with the next ON of the main switch, the voltage of the electrical equipment battery will be equal to or higher than the normal operating voltage of the controller, allowing the vehicle to be driven.

[0035] In a fourth aspect, in the third aspect, when the main switch is turned on, the current consumption of the electrical components and the controller causes the voltage of the electrical component battery to fall below the normal operating voltage of the controller, and when the main switch is turned off, only the current consumption of the controller causes the voltage of the electrical component battery to exceed the normal operating voltage of the controller. With this configuration, when the electrical components are turned on in conjunction with the main switch being turned on, the current consumption of the electrical components and the controller may cause the voltage of the electrical component battery to fall below the normal operating voltage of the controller. Even in this case, when the electrical components are turned off in conjunction with the main switch being turned off, only the current consumption of the controller occurs, and the voltage of the electrical component battery exceeds the normal operating voltage of the controller, the electrical component battery will be charged.

[0036] Although the present embodiment has been described, other embodiments may be made by combining the above-described embodiments and modifications in whole or in part.

[0037] Furthermore, the technology of the present invention is not limited to the above-described embodiments, and various changes, substitutions, and modifications may be made without departing from the spirit of the technical idea. Furthermore, if the technical idea can be realized in a different way due to technological advances or other derived technologies, it may be implemented using that method. Therefore, the claims cover all embodiments that may fall within the scope of the technical idea. [Explanation of symbols]

[0038] 1: Power system 11: Electric motor 12: Drive battery 13: Lighting equipment (electrical equipment) 14: Electrical equipment battery 16: DC / DC converter (converter) 21: Controller 22: Ignition switch (main switch)

Claims

1. A power supply system for a vehicle equipped with electrical equipment and an electric motor, an electrical equipment battery that supplies power to the electrical equipment; a drive battery that supplies power to the electric motor; a converter that reduces the power of the driving battery and outputs the reduced power to the electrical equipment battery; a controller that is driven by power from the electrical equipment battery and controls the converter, A power supply system characterized in that, when the voltage of the electrical equipment battery is lower than the normal operating voltage of the controller when the main switch is ON, and when the voltage of the electrical equipment battery becomes equal to or higher than the normal operating voltage of the controller when the main switch is OFF, the controller controls the converter to charge the electrical equipment battery with power from the drive battery.

2. 2. The power supply system according to claim 1, wherein the controller controls the converter to stop charging the electrical equipment battery after a predetermined time has elapsed since the start of charging.

3. 3. The power supply system according to claim 1, wherein the electrical components are turned on and off in conjunction with the main switch.

4. 4. The power supply system according to claim 3, wherein when the main switch is turned on, the voltage of the electrical equipment battery becomes less than the normal operating voltage of the controller due to the current consumption of the electrical equipment and the controller, and when the main switch is turned off, only the current consumption of the controller remains, causing the voltage of the electrical equipment battery to become equal to or greater than the normal operating voltage of the controller.

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