JP2020044922A - Power supply device for vehicle - Google Patents

Abstract

To protect a power storage unit.SOLUTION: A power supply device for a vehicle includes: a first power supply system 71 having a lead battery 51 and an electrical apparatus 63; a second power supply system 72 having a starter generator 16 and a lithium-ion battery 52; an ISG control section 91 and a lead battery protection control section 95 for controlling power generation voltage of the starter generator 16 when terminal voltage of the lead battery 51 reaches limit voltage; a voltage detection section 67 for detecting terminal voltage of the lead battery 51 and transmitting the terminal voltage as first voltage information Dv1; and a voltage detection section 83 for detecting power supply voltage of the electrical apparatus 63 and transmitting the power supply voltage as second voltage information Dv2. The ISG control section 91 and the lead battery protection control section 95 control the power generation voltage of the starter generator 16 on the basis of the first voltage information Dv1 when the voltage detection section 67 is normal, and control the power generation voltage of the starter generator 16 on the basis of the second voltage information Dv2 when the voltage detection section 67 is abnormal.SELECTED DRAWING: Figure 12

Description

  The present invention relates to a vehicle power supply device mounted on a vehicle.

  A vehicle power supply device mounted on a vehicle is provided with a power storage unit such as a lead battery or a lithium ion battery, and is provided with a generator such as a motor generator or an ISG (Integrated Starter Generator) (Patent Documents 1 to 3). 4).

JP 2004-251744 A JP 2007-282375 A JP 2009-166632 A JP 2013-109860 A

  By the way, in order to stabilize the power supply capability of the vehicle power supply device, it is necessary to prevent the power storage unit from being overcharged or overdischarged. For this reason, a voltage sensor is provided in the power storage unit, and the terminal voltage of the power storage unit is monitored by a controller or the like. When the terminal voltage of the power storage unit excessively increases, the power generation voltage of the generator is reduced. On the other hand, when the terminal voltage of the power storage unit excessively decreases, the power generation voltage of the generator is raised. However, when an abnormality occurs in the voltage sensor provided in the power storage unit, the terminal voltage of the power storage unit cannot be grasped, so that the power storage unit may be overcharged or overdischarged.

  An object of the present invention is to protect a power storage unit.

  A vehicular power supply device of the present invention is a vehicular power supply device mounted on a vehicle, comprising: a first power supply system including a first power storage unit; and an electric device connected to the first power storage unit; and an engine. A second power supply system including a generator connected to the first power supply and a second power storage unit connected to the generator; and a second power supply system provided between the first power supply system and the second power supply system. An energization path that connects the power storage unit and the second power storage unit in parallel, a power generation control unit that controls a power generation voltage of the generator when a terminal voltage of the first power storage unit reaches a limit voltage, A first voltage detection unit that detects a terminal voltage of one power storage unit and transmits the terminal voltage to the power generation control unit as first voltage information; and detects a power supply voltage of the electric device and converts the power supply voltage to a second voltage. A second voltage detection unit that transmits the information to the power generation control unit, and wherein the power generation control unit When the first voltage detecting section is normal, the control section controls the generated voltage of the generator based on the first voltage information. On the other hand, when the first voltage detecting section is abnormal, the second voltage is controlled. The generated voltage of the generator is controlled based on the information.

  According to the present invention, the power generation control unit controls the power generation voltage of the generator based on the first voltage information when the first voltage detection unit is normal, and when the first voltage detection unit is abnormal. Then, the power generation voltage of the generator is controlled based on the second voltage information. Thereby, even if an abnormality occurs in the first voltage detection unit, the first power storage unit can be protected.

FIG. 1 is a schematic diagram illustrating a configuration example of a vehicle equipped with a vehicle power supply device according to an embodiment of the present invention. FIG. 2 is a circuit diagram schematically illustrating an example of a power supply circuit. It is a figure which shows an example of the electric current supply situation at the time of controlling a starter generator to a combustion power generation state. It is a figure which shows an example of the electric current supply situation at the time of controlling a starter generator to a power generation suspension state. FIG. 5 is a diagram illustrating an example of a current supply state when the starter generator is controlled to a regenerative power generation state. It is a figure which shows an example of the electric current supply situation at the time of controlling a starter generator to a power running state. It is a figure which shows an example of the electric current supply situation at the time of controlling a starter generator to a power running state. FIG. 5 is a diagram illustrating an example of a current supply state in engine initial start control. It is a figure showing an example of the current supply situation in lead battery supplementary charge control. It is a flowchart which shows an example of the execution procedure of lead battery protection control. 5 is a flowchart illustrating an example of an execution procedure of fail-safe control. FIG. 4 is a diagram illustrating a reception state of voltage information Dv1 and Dv2 by a main controller.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Vehicle configuration]
FIG. 1 is a schematic diagram showing a configuration example of a vehicle 11 on which a vehicle power supply device 10 according to an embodiment of the present invention is mounted. As shown in FIG. 1, a vehicle 11 is equipped with a power unit 13 using an engine 12 as a power source. A starter generator (generator) 16 is connected to a crankshaft 14 of the engine 12 via a belt mechanism 15. A transmission mechanism 18 is connected to the engine 12 via a torque converter 17, and wheels 20 are connected to the transmission mechanism 18 via a differential mechanism 19 and the like.

  The starter generator 16 connected to the engine 12 is a so-called ISG (Integrated Starter Generator) that functions as a generator and an electric motor. The starter generator 16 functions not only as a generator driven by the crankshaft 14 but also as an electric motor for driving the crankshaft 14. For example, when the engine 12 is restarted in the idling stop control, or when the engine 12 is assisted at the time of starting or accelerating, the starter generator 16 is controlled to the power running state, and the starter generator 16 functions as an electric motor.

  The starter generator 16 has a stator 30 provided with a stator coil, and a rotor 31 provided with a field coil. In addition, the starter generator 16 is provided with an ISG controller 32 including an inverter, a regulator, a microcomputer, various sensors, and the like in order to control an energized state of the stator coil and the field coil. By controlling the energized state of the field coil and the stator coil by the ISG controller 32, the power generation voltage, the power generation torque, the power running torque, and the like of the starter generator 16 can be controlled.

  Further, the power unit 13 is provided with a starter motor 40 for starting and rotating the engine 12. The pinion 41 of the starter motor 40 is movable between a protruding position where it meshes with the ring gear 42 of the torque converter 17 and a retracted position where the engagement with the ring gear 42 is released. As will be described later, when the starter button 43 is pressed by the occupant, the starter relay 44 that controls the energization of the starter motor 40 is switched on. As a result, power is supplied to the starter motor 40 via the starter relay 44, and the pinion 41 of the starter motor 40 moves to the projecting position and rotates. Further, in order to control the starter motor 40 via the starter relay 44, the vehicle 11 is provided with an engine controller 45 including a microcomputer or the like. The engine controller 45 not only controls the starter relay 44 but also controls engine accessories 46 such as a throttle valve, an injector, and an ignition device.

  As described above, the illustrated vehicle 11 is provided with the starter generator 16 and the starter motor 40. When the engine 12 is restarted according to the idling stop control, that is, when the stop condition is satisfied while the engine is running, the engine 12 is stopped, and when the start condition is satisfied while the engine is stopped, the engine 12 is restarted. The start rotation of the engine 12 is performed by using the starter generator 16. On the other hand, when the control system of the vehicle 11 is started to start the engine 12 first, that is, when the engine 12 is started by an occupant's operation of a starter button or the like, the start rotation of the engine 12 is performed using the starter motor 40. Will be

[Power supply circuit]
The power supply circuit 50 included in the vehicle power supply device 10 will be described. FIG. 2 is a circuit diagram schematically illustrating an example of the power supply circuit 50. As shown in FIG. 2, power supply circuit 50 includes a lead battery (first power storage) 51 electrically connected to starter generator 16 and a lithium ion battery electrically connected to starter generator 16 in parallel with the lead battery. (Second power storage unit) 52. In order to positively discharge the lithium ion battery 52, the terminal voltage of the lithium ion battery 52 is designed to be higher than the terminal voltage of the lead battery 51. Further, in order to positively charge and discharge the lithium ion battery 52, the internal resistance of the lithium ion battery 52 is designed to be smaller than the internal resistance of the lead battery 51.

  A positive electrode line 53 is connected to the positive terminal 16 a of the starter generator 16, a positive line 54 is connected to the positive terminal 52 a of the lithium ion battery 52, and a positive line 55 is connected to the positive terminal 51 a of the lead battery 51 via the positive line 55. 56 are connected. These positive electrode lines 53, 54, 56 are connected to each other via a connection point 57. A negative electrode line 58 is connected to the negative terminal 16 b of the starter generator 16, a negative line 59 is connected to the negative terminal 52 b of the lithium ion battery 52, and a negative line 60 is connected to the negative terminal 51 b of the lead battery 51. You. These negative electrode lines 58, 59, 60 are connected to each other via a reference potential point 61.

  As shown in FIG. 1, a positive electrode line 62 is connected to the positive electrode line 55 of the lead battery 51. An electric device group 64 including electric devices 63 such as various actuators and various controllers is connected to the positive electrode line 62. A battery sensor 65 is provided on the negative electrode line 60 of the lead battery 51. The battery sensor 65 includes a current detection unit 66 that detects a charge / discharge current (current) of the lead battery 51, a voltage detection unit (first voltage detection unit) 67 that detects a terminal voltage (voltage) of the lead battery 51, and a lead battery. It has a remaining amount calculation unit 68 that calculates an SOC (State Of Charge), which is the state of charge of 51, and a self-diagnosis unit 69 that detects a sensor abnormality. The remaining amount calculation unit 68 of the battery sensor 65 calculates the SOC of the lead battery 51 based on the charge / discharge current and the terminal voltage of the lead battery 51, and transmits the SOC to a main controller 80 described later. Note that the SOC of the lead battery 51 is a ratio indicating the remaining amount of electricity of the lead battery 51, and is a ratio of the charged amount to the full charge capacity of the lead battery 51. For example, when the lead battery 51 is charged to the upper limit capacity, the SOC is calculated as 100%, and when the lead battery 51 is discharged to the lower limit capacity, the SOC is calculated as 0%.

  As described above, the battery sensor 65 has a function of calculating the SOC of the lead battery 51 based on the charge / discharge current, the terminal voltage, and the like of the lead battery 51. For example, the SOC of the lead battery 51 can be calculated by integrating the charge / discharge current of the lead battery 51. Further, it is possible to estimate the SOC of the lead battery 51 by estimating the remaining charged amount from the terminal voltage of the lead battery 51. The battery sensor 65 may calculate the SOC based only on the charging / discharging current, may calculate the SOC based only on the terminal voltage, or may calculate the SOC based on both the charging / discharging current and the terminal voltage. Is also good. Further, the battery sensor 65 detects both the charge / discharge current and the terminal voltage, but is not limited to this, and may detect only the charge / discharge current, or may detect only the terminal voltage. good. The battery sensor 65 is also connected to a positive terminal 51a of the lead battery 51 via an unillustrated energizing line.

  The power supply circuit 50 includes a first power supply system 71 including a lead battery 51 and an electric device 63, and a second power supply system 72 including a lithium ion battery 52 and a starter generator 16. Then, the lead battery 51 and the lithium ion battery 52 are connected in parallel to each other via a positive electrode line (power supply path) 56 provided between the first power supply system 71 and the second power supply system 72. The positive line 56 is provided with a power fuse 73 that is blown by an excessive current and a first switch SW1 that is controlled between an on state and an off state. Further, a second switch SW2 that is controlled between an on state and an off state is provided on the positive electrode line 54 of the lithium ion battery 52.

  By controlling the switch SW1 to the on state, the first power supply system 71 and the second power supply system 72 can be connected to each other. On the other hand, by controlling the switch SW1 to the off state, the first power supply system 71 and the second power supply system 71 can be connected. The two power supply systems 72 can be separated from each other. By controlling the switch SW2 to be on, the starter generator 16 and the lithium ion battery 52 can be connected to each other. On the other hand, by controlling the switch SW2 to be off, the starter generator 16 and the lithium ion battery 52 can be connected. Can be separated from each other.

  These switches SW1 and SW2 may be switches configured by semiconductor elements such as MOSFETs, or may be switches that mechanically open and close contacts using electromagnetic force or the like. The ON state of the switches SW1 and SW2 means an energized state and a conductive state that are electrically connected, and the OFF state of the switches SW1 and SW2 means a non-energized state and a cutoff state that are electrically disconnected. Means state. The switches SW1 and SW2 are also called relays, contactors, and the like.

  As shown in FIG. 1, the power supply circuit 50 includes a battery module 74. The battery module 74 includes the lithium ion battery 52 and switches SW1 and SW2. The battery module 74 has a battery controller 75 including a microcomputer, various sensors, and the like. Further, the battery module 74 is provided with a battery sensor 76 for detecting a charge / discharge current, a terminal voltage, a temperature, and the like of the lithium ion battery 52. Further, the battery controller 75 has a function of calculating an SOC (State Of Charge), which is a state of charge of the lithium ion battery 52, based on a charge / discharge current, a terminal voltage, and the like transmitted from the battery sensor 76. The battery controller 75 has a function of controlling the switches SW1 and SW2 based on the SOC of the lithium ion battery 52 and the like. Note that the SOC of the lithium-ion battery 52 is a ratio indicating the remaining amount of electricity in the lithium-ion battery 52, and is a ratio of the charged amount to the full charge capacity of the lithium-ion battery 52. For example, when the lithium ion battery 52 is charged to the upper limit capacity, the SOC is calculated as 100%, and when the lithium ion battery 52 is discharged to the lower limit capacity, the SOC is calculated as 0%.

  As described above, the battery controller 75 has a function of calculating the SOC of the lithium ion battery 52 based on the charge / discharge current, the terminal voltage, and the like of the lithium ion battery 52. For example, the SOC of the lithium ion battery 52 can be calculated by integrating the charge / discharge current of the lithium ion battery 52. In addition, it is possible to estimate the remaining charge amount from the terminal voltage of the lithium ion battery 52 and calculate the SOC of the lithium ion battery 52. The battery controller 75 may calculate the SOC based only on the charge / discharge current, may calculate the SOC based only on the terminal voltage, or may calculate the SOC based on both the charge / discharge current and the terminal voltage. Is also good. Further, the battery sensor 76 detects both the charge / discharge current and the terminal voltage, but is not limited to this, and may detect only the charge / discharge current, or may detect only the terminal voltage. good.

[Control system]
As shown in FIG. 1, the vehicle power supply device 10 includes a main controller 80 including a microcomputer or the like in order to control the power unit 13, the power supply circuit 50, and the like in cooperation with each other. The main controller 80 is provided with a power supply unit 81, and the power supply unit 81 is connected to the positive electrode line 62 via the power supply line 82. That is, the main controller 80 is provided as one of the electric devices 63 included in the electric device group 64. Further, the power supply section 81 of the main controller (electronic control unit) 80 is provided with a voltage detection section (second voltage detection section) 83 for detecting the power supply voltage of the main controller 80. The voltage detector 67 has a function of detecting a power supply voltage of the main controller 80 and transmitting the detected power supply voltage to a lead battery protection controller 95 in the main controller 80 described later.

  The main controller 80 includes an engine control unit 90 that controls the engine 12, an ISG control unit (power generation control unit) 91 that controls the starter generator 16, and a switch control unit 92 that controls the switches SW1 and SW2. Further, the main controller 80 has an idling control unit 93 for executing an idling stop control described later, and has an assist control unit 94 for executing a motor assist control described later. Further, the main controller 80 has a lead battery protection control unit (power generation control unit) 95 that executes lead battery protection control described later. The lead battery protection control unit 95 has a function of executing a fail-safe control described later.

  The main controller 80 and the above-described controllers 32, 45, and 75 are communicably connected to each other via an in-vehicle network 97 such as CAN or LIN. The main controller 80 controls the power unit 13, the power supply circuit 50, and the like based on information from various controllers and various sensors. The main controller 80 controls the starter generator 16 via the ISG controller 32 and controls the switches SW1 and SW2 via the battery controller 75. The main controller 80 controls the engine 12 and the starter motor 40 via the engine controller 45.

[Starter generator power generation control]
Next, power generation control of the starter generator 16 by the main controller 80 will be described. The ISG control section 91 of the main controller 80 outputs a control signal to the ISG controller 32 to control the starter generator 16 to a power generation state or a power running state. For example, when the SOC of the lithium ion battery 52 decreases, the ISG control unit 91 increases the power generation voltage of the starter generator 16 to control the combustion power generation state, while when the SOC of the lithium ion battery 52 increases, the power generation of the starter generator 16 The voltage is reduced to control the power generation to a halt state. In the drawings after FIG. 3 described later, “ISG” means starter generator 16.

  FIG. 3 is a diagram illustrating an example of a current supply state when the starter generator 16 is controlled to a combustion power generation state. The combustion power generation state of the starter generator 16 is a state in which the starter generator 16 generates power by engine power, that is, a state in which fuel is burned in the engine to generate power. For example, when the SOC of the lithium ion battery 52 is lower than a predetermined lower limit, the starter generator 16 is caused to generate power by engine power in order to charge the lithium ion battery 52 and increase the SOC. As described above, when the starter generator 16 is controlled to the combustion power generation state, the voltage generated by the starter generator 16 is higher than the terminal voltages of the lead battery 51 and the lithium ion battery 52. As a result, as shown by the black arrows in FIG. Is charged slowly.

  FIG. 4 is a diagram illustrating an example of a current supply state when the starter generator 16 is controlled to be in the power generation suspension state. For example, when the SOC of the lithium-ion battery 52 exceeds a predetermined upper limit, the power generation of the starter generator 16 using the engine power is stopped in order to positively discharge the lithium-ion battery 52. As described above, when the starter generator 16 is controlled to be in the power generation suspension state, the voltage generated by the starter generator 16 is lower than the terminal voltages of the lead battery 51 and the lithium ion battery 52. As a result, as shown by black arrows in FIG. 4, current is supplied from the lithium-ion battery 52 to the electric device group 64, so that the power generation of the starter generator 16 can be stopped, and the engine load can be reduced. Can be. Note that the power generation voltage of the starter generator 16 in the power generation suspension state may be any power generation voltage that discharges the lithium ion battery 52. For example, the generated voltage of the starter generator 16 may be controlled to 0V, or the generated voltage of the starter generator 16 may be controlled to be higher than 0V.

  As described above, the ISG control unit 91 of the main controller 80 controls the starter generator 16 in the combustion power generation state or the power generation stop state based on the SOC of the lithium ion battery 52, but recovers a large amount of kinetic energy when the vehicle decelerates. To improve fuel efficiency. Therefore, when the vehicle is decelerated, the generated voltage of the starter generator 16 is raised, and the starter generator 16 is controlled to a regenerative power generation state. As a result, the power generated by the starter generator 16 can be increased, so that the kinetic energy can be positively converted into electric energy and recovered, and the energy efficiency of the vehicle 11 can be increased to improve fuel efficiency. it can. Whether or not to execute such regenerative power generation is determined based on the operation status of the accelerator pedal and the brake pedal. That is, the starter generator 16 is controlled to the regenerative power generation state during deceleration running when the depression of the accelerator pedal is released or during deceleration running when the brake pedal is depressed.

  Here, FIG. 5 is a diagram illustrating an example of a current supply state when the starter generator 16 is controlled to the regenerative power generation state. When controlling the starter generator 16 to the regenerative power generation state, the generated voltage of the starter generator 16 is higher than in the combustion power generation state described above. As a result, a large current is supplied from the starter generator 16 to the lithium-ion battery 52 and the lead battery 51, as indicated by the black arrow in FIG. Charged. Further, since the internal resistance of the lithium ion battery 52 is smaller than the internal resistance of the lead battery 51, most of the generated current is supplied to the lithium ion battery 52.

  Note that, as shown in FIGS. 3 to 5, when the starter generator 16 is controlled to the combustion power generation state, the regenerative power generation state, and the power generation suspension state, the switches SW1 and SW2 are kept on. That is, in the vehicle power supply device 10, the charge / discharge of the lithium ion battery 52 can be controlled only by controlling the generated voltage of the starter generator 16 without performing the switching control of the switches SW1 and SW2. Thus, not only can the charge / discharge of the lithium ion battery 52 be easily controlled, but also the durability of the switches SW1 and SW2 can be improved.

[Engine restart in idling stop control]
The idling control unit 93 of the main controller 80 executes an idling stop control for automatically stopping and restarting the engine 12. The idling control unit 93 performs a fuel cut or the like to stop the engine 12 when a predetermined stop condition is satisfied during operation of the engine. The engine 16 is restarted by rotating the engine 16. The stop condition of the engine 12 includes, for example, that the vehicle speed falls below a predetermined value and the brake pedal is depressed. The start conditions of the engine 12 include, for example, that the depression of the brake pedal is released, and that the depression of the accelerator pedal is started. Note that the idling control unit 93 outputs a control signal to the engine control unit 90 and the ISG control unit 91 to execute the idling stop control, and controls the engine 12 and the starter generator 16.

  Further, when a start condition is satisfied while the engine is stopped in the idling stop control, the idling control unit 93 controls the starter generator 16 to be in a power running state and starts and rotates the engine 12. Here, FIG. 6 is a diagram illustrating an example of a current supply state when the starter generator 16 is controlled to the power running state. As shown in FIG. 6, when the starter generator 16 is controlled to the power running state when the engine is restarted in the idling stop control, the switch SW1 is controlled to be in an off state, and the switch SW2 is controlled to be in an on state. That is, when the engine 12 is started and rotated by the starter generator 16, the switch SW1 is turned off, and the first power supply system 71 and the second power supply system 72 are separated from each other. Thus, even when a large current is supplied from lithium-ion battery 52 to starter generator 16, it is possible to prevent instantaneous voltage drop from first power supply system 71 to electric equipment group 64, 64 etc. can function normally.

[Motor assist control]
The assist controller 94 of the main controller 80 controls the starter generator 16 to be in a power running state at the time of starting or accelerating, and executes motor assist control for assisting the engine 12 with the starter generator 16. When executing the motor assist control, the assist control unit 94 outputs a control signal to the ISG control unit 91 to control the starter generator 16.

  Here, FIG. 7 is a diagram illustrating an example of a current supply state when the starter generator 16 is controlled to the power running state. As shown in FIG. 7, when the starter generator 16 is controlled to the power running state in accordance with the motor assist control, the switches SW1 and SW2 are both controlled to the on state. As described above, when the engine 12 is assisted by the starter generator 16, by controlling the switches SW1 and SW2 to the ON state, both the lead battery 51 and the lithium ion battery 52 are connected to the electric device group 64. I have. Thereby, the power supply voltage of the electric equipment group 64 can be stabilized, and the reliability of the vehicle power supply device 10 can be improved.

  As described above, when the engine is restarted by the starter generator 16, the switch SW1 is switched to the off state, while when the starter generator 16 assists the motor, the switch SW1 is held in the on state. That is, the engine restart is a situation in which the stopped engine 12 starts to be rotated by the starter generator 16, and the power consumption of the starter generator 16 tends to increase. On the other hand, at the time of motor assist is a situation in which the rotating engine 12 is supplementarily driven by the starter generator 16, and a situation in which the power consumption of the starter generator 16 is suppressed. As described above, in the motor assist control, since the power consumption of the starter generator 16 is suppressed, a large current does not flow from the lead battery 51 to the starter generator 16 even if the switch SW1 is held in the ON state. The power supply voltage of the electric device group 64 can be stabilized.

[Engine first start control, lead battery supplementary charge control]
Subsequently, after describing the initial engine start control for starting the engine 12 using the starter motor 40, the lead battery supplementary charge control by the starter generator 16 after the initial engine start will be described. Here, FIG. 8 is a diagram showing an example of a current supply state in the engine initial start control. FIG. 9 is a diagram showing an example of a current supply state in the lead battery supplementary charge control.

  When the control system of the vehicle 11 is started and the engine 12 is first started, that is, when the engine 12 is started by operating a starter button or the like, the starter motor 40 rotates the engine 12 to start. In the engine initial start control, as shown in FIG. 8, the switch SW1 is controlled to be off, the switch SW2 is controlled to be off, and the starter relay 44 is controlled to be on. Thus, current is supplied from the lead battery 51 to the starter motor 40, and the engine 12 is started by rotating the starter motor 40.

  As described above, when the engine 12 is started by the starter motor 40, the starter relay 44 is switched off, the switch SW1 is switched on, and the starter generator 16 is switched to the combustion power generation state, as shown in FIG. Controlled. That is, when the engine 12 is started, the switch SW1 is turned on while the switch SW2 is kept off, and the starter generator 16 is controlled to the combustion power generation state. As a result, the lead battery 51 can be positively charged by the starter generator 16, and the SOC of the lead battery 51, which decreases when the vehicle is stopped or when the engine is started for the first time, can be recovered.

  That is, when the vehicle is stopped, a dark current flows from the lead battery 51 to the electric device group 64, and a large current flows from the lead battery 51 to the starter motor 40 when the engine is initially started. SOC gradually decreases. For this reason, the reduced SOC of the lead battery 51 is recovered by executing the lead battery supplementary charge control after the initial start of the engine. Note that the lead battery supplementary charge control after the initial engine start may be continued for a predetermined time, or may be continued until the SOC of the lead battery 51 recovers to a predetermined value.

[Lead battery protection control]
Next, the lead battery protection control executed by the main controller 80 will be described. The lead battery protection control is control for determining overdischarge or overcharge of the lead battery 51 based on the terminal voltage VPb of the lead battery 51 and protecting the lead battery 51 from overdischarge or overcharge, as described later. The lead battery protection control is executed by the main controller 80 at predetermined intervals.

  FIG. 10 is a flowchart illustrating an example of an execution procedure of the lead battery protection control. As shown in FIG. 10, in step S10, it is determined whether the terminal voltage VPb of the lead battery 51 exceeds a predetermined upper limit voltage (limit voltage) Vmax. In step S10, when it is determined that the terminal voltage VPb is higher than the upper limit voltage Vmax, that is, when it is determined that the lead battery 51 is overcharged, the process proceeds to step S11, where the power generation voltage of the starter generator 16 increases. It is forbidden. That is, in the case where the process proceeds to step S11, the generation voltage is lowered or maintained according to the situation, even if an increase in the generation voltage is required by regenerative power generation or the like during vehicle deceleration.

  If it is determined in step S10 that the terminal voltage VPb of the lead battery 51 is equal to or lower than the upper limit voltage Vmax, the process proceeds to step S12, where the terminal voltage VPb of the lead battery 51 is reduced to a predetermined lower limit voltage (limit voltage) Vmin. Is determined. If it is determined in step S12 that the terminal voltage VPb is lower than the lower limit voltage Vmin, that is, if it is determined that the lead battery 51 is overdischarged, the process proceeds to step S13, where the generation voltage of the starter generator 16 decreases. It is forbidden. That is, when the process proceeds to step S13, even if a reduction in the generated voltage is required due to an increase in the SOC of the lithium-ion battery 52 or the like, the generated voltage is raised or held according to the situation.

  If it is determined in step S12 that the terminal voltage VPb of the lead battery 51 is equal to or higher than the lower limit voltage Vmin, that is, if it is determined that the lead battery 51 is not overcharged or overdischarged, the process proceeds to step S14. , The normal control of the starter generator 16 is executed. That is, in step S14, as shown in FIGS. 3 to 7 described above, starter generator 16 performs combustion power generation based on the SOC of lithium ion battery 52, the execution status of idling stop control, or the execution status of motor assist control. It is controlled to a state, a power generation suspension state, a regenerative power generation state, or a power running state.

  As described above, when the terminal voltage VPb of the lead battery 51 reaches the upper limit voltage Vmax, the increase in the power generation voltage of the starter generator 16 is prohibited, while the terminal voltage VPb of the lead battery 51 reaches the lower limit voltage Vmin. In this case, the decrease in the generated voltage of the starter generator 16 is prohibited. Thus, overcharging and overdischarging of the lead battery 51 can be prevented, and the lead battery 51 can be protected.

[Fail safe control]
As described above, by executing the lead battery protection control, the lead battery 51 is protected from overdischarge and overcharge. However, when an abnormality occurs in the battery sensor 65 that detects the terminal voltage VPb of the lead battery 51, the terminal voltage VPb of the lead battery 51 cannot be grasped, so that the lead battery protection control can be appropriately executed. Have difficulty. Therefore, when detecting an abnormality in the battery sensor 65, the main controller 80 executes fail-safe control from the viewpoint of protecting the lead battery 51. This fail-safe control is executed by the main controller 80 at predetermined intervals.

  Next, a description will be given of the fail-safe control when an abnormality occurs in the battery sensor 65 of the lead battery 51. Here, FIG. 11 is a flowchart illustrating an example of the execution procedure of the fail-safe control. As shown in FIG. 11, in step S20, it is determined whether an abnormality has occurred in battery sensor 65. In step S20, when an abnormality is detected by the self-diagnosis unit 69 of the battery sensor 65, it is determined that an abnormality has occurred in the battery sensor 65.

  If it is determined in step S20 that the battery sensor 65 is abnormal, the process proceeds to step S21, and based on the second voltage information Dv2 transmitted from the voltage detection unit 67 in the main controller 80, as shown in FIG. The lead battery protection control is executed. On the other hand, if it is determined in step S20 that the battery sensor 65 is normal, the process proceeds to step S22, and based on the first voltage information Dv1 transmitted from the battery sensor 65, the lead battery protection shown in FIG. Control is executed.

  That is, when the battery sensor 65 is normal, the power generation voltage of the starter generator 16 is controlled based on the first voltage information Dv1, while when the battery sensor 65 is abnormal, based on the second voltage information Dv2. The generated voltage of the starter generator 16 is controlled. Thus, even if an abnormality occurs in the battery sensor 65, the terminal voltage VPb of the lead battery 51 can be estimated using the second voltage information Dv2, that is, the power supply voltage of the main controller 80. Protection control can be appropriately performed.

  Here, FIG. 12 is a diagram illustrating a reception state of the first and second voltage information Dv1 and Dv2 by the main controller 80. In FIG. 12, the same components and members as those shown in FIGS. 1 and 2 are denoted by the same reference numerals and description thereof will be omitted. As shown in FIG. 12, to the lead battery protection control unit 95 of the main controller 80, the first voltage information Dv1 is transmitted from the battery sensor 65, and the second voltage information Dv2 is transmitted from the voltage detection unit 67 in the controller. Is done. Further, a signal indicating whether the battery sensor 65 is normal or abnormal is transmitted from the self-diagnosis unit 69 of the battery sensor 65 to the lead battery protection control unit 95.

  When determining that the battery sensor 65 is normal, the lead battery protection control unit 95 determines the terminal voltage VPb of the lead battery 51 based on the first voltage information Dv1 from the battery sensor 65, and determines the terminal voltage VPb based on the terminal voltage VPb. The lead battery protection control described above is executed. On the other hand, when determining that the battery sensor 65 is abnormal, the lead battery protection control unit 95 determines the terminal voltage VPb of the lead battery 51 based on the second voltage information Dv2 from the voltage detecting unit 67 in the controller. The lead battery protection control described above is executed based on the voltage VPb.

  That is, when the terminal voltage VPb cannot be appropriately detected by the battery sensor 65, the lead battery protection control is executed by using the power supply voltage of the main controller 80 as the terminal voltage VPb of the lead battery 51. . Thus, even if an abnormality occurs in the battery sensor 65, the lead battery protection control can be appropriately performed based on the power supply voltage of the main controller 80, and the lead battery 51 is protected from overcharge or overdischarge. can do. As described above, even when an abnormality occurs in the battery sensor 65, the lead battery 51 can be protected from overcharging or overdischarging. Therefore, as shown in FIGS. The starter generator 16 can be controlled while being kept in the ON state.

  Further, as shown by an arrow α in FIG. 12, since the voltage drops in the process where the current flows from the lead battery 51 to the main controller 80, the second voltage information Dv2 is detected to be lower than the first voltage information Dv1 by the voltage drop ΔV. Is done. Therefore, when the battery sensor 65 is abnormal, the lead battery protection control unit 95 adds the voltage drop ΔV between the lead battery 51 and the main controller 80 to the second voltage information Dv2, and the voltage drop ΔV becomes The lead battery protection control is executed based on the added second voltage information Dv2. That is, on the basis of the second voltage information Dv2 to which the voltage drop ΔV has been added, the rise or fall of the generated voltage of the starter generator 16 is prohibited. As described above, by adding the voltage drop ΔV to the second voltage information Dv2, the terminal voltage VPb of the lead battery 51 can be accurately estimated, and the lead battery protection control can be more appropriately executed.

  The present invention is not limited to the above embodiment, and it goes without saying that various changes can be made without departing from the spirit of the present invention. In the above description, as the electric motor connected to the engine 12, the starter generator 16 functioning as a motor and a generator is adopted. However, the present invention is not limited to this, and an alternator functioning only as a generator is adopted. Is also good. In the above description, the lead battery 51 is used as the first power storage unit. However, the present invention is not limited to this, and another type of battery or capacitor may be used as the first power storage unit. Further, although the lithium ion battery 52 is used as the second power storage unit, the invention is not limited to this, and another type of battery or capacitor may be used as the second power storage unit. Further, in the example shown in FIGS. 1 and 2, the switch SW2 is provided on the positive electrode line 54 of the lithium ion battery 52, but the present invention is not limited to this. For example, as shown by a dashed line in FIG. 2, a switch SW2 may be provided on the negative electrode line 59 of the lithium ion battery 52.

  In the above description, the self-diagnosis unit 69 in the battery sensor 65 determines whether or not the battery sensor 65 is abnormal. However, the present invention is not limited to this. For example, when the voltage value detected by the battery sensor 65 is out of the predetermined voltage detection range, it may be determined that the battery sensor 65 is abnormal. In the above description, the lead battery 51 is protected from both overcharging and overdischarging by executing the lead battery protection control. However, the present invention is not limited to this. For example, the lead battery 51 may be protected from overcharge only by executing the lead battery protection control, or the lead battery 51 may be protected only from overdischarge by executing the lead battery protection control. In the above description, the main controller 80 is provided with the various control units 90 to 95, but the present invention is not limited to this. Some or all of the various control units 90 to 95 may be provided in another controller.

Reference Signs List 10 vehicle power supply device 11 vehicle 12 engine 16 starter generator (generator)
51 Lead battery (first power storage)
52 Lithium ion battery (second power storage unit)
56 Positive electrode line (current path)
63 electrical equipment 67 voltage detector (first voltage detector)
71 First power supply system 72 Second power supply system 80 Main controller (electrical equipment, electronic control unit)
83 voltage detector (second voltage detector)
91 ISG control unit (power generation control unit)
95 Lead battery protection control unit (power generation control unit)
VPb terminal voltage Vmax Upper limit voltage (limit voltage)
Vmin Lower limit voltage (limit voltage)
Dv1 First voltage information Dv2 Second voltage information ΔV Voltage drop

Claims (4)

A vehicle power supply device mounted on a vehicle,
A first power supply system including a first power storage unit and an electric device connected to the first power storage unit;
A second power supply system including a generator connected to the engine, and a second power storage unit connected to the generator;
An energization path that is provided between the first power supply system and the second power supply system and that connects the first power storage unit and the second power storage unit in parallel;
A power generation control unit that controls a power generation voltage of the generator when a terminal voltage of the first power storage unit reaches a limit voltage;
A first voltage detection unit that detects a terminal voltage of the first power storage unit and transmits the terminal voltage to the power generation control unit as first voltage information;
A second voltage detection unit that detects a power supply voltage of the electric device and transmits the power supply voltage to the power generation control unit as second voltage information;
Has,
The power generation control unit,
When the first voltage detection unit is normal, while controlling the generated voltage of the generator based on the first voltage information,
If the first voltage detection unit is abnormal, control the generated voltage of the generator based on the second voltage information,
Power supply for vehicles. The power supply device for a vehicle according to claim 1,
The power generation control unit adds a voltage drop between the first power storage unit and the electric device to the second voltage information when the first voltage detection unit is abnormal, and the voltage drop is Controlling the generated voltage of the generator based on the added second voltage information;
Power supply for vehicles. The vehicle power supply device according to claim 1 or 2,
As the limit voltage, there is an upper limit voltage and a lower limit voltage,
When the terminal voltage of the first power storage unit reaches the upper limit voltage, the power generation control unit prohibits an increase in the power generation voltage of the generator while the terminal voltage of the first power storage unit reaches the lower limit voltage In the case, prohibiting a decrease in the generated voltage of the generator,
Power supply for vehicles. The vehicle power supply device according to any one of claims 1 to 3,
The second voltage detection unit is provided in an electronic control unit that is the electric device,
Power supply for vehicles.

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