JP2018057202A - Power supply device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve energy efficiency of a vehicle by increasing regenerative electric power.SOLUTION: The power supply device has: a starter generator 16 coupled with an engine; a lithium ion battery 31 connected to the starter generator 16 via a connection point 36; a lead battery 32 connected to the starter generator 16 via the connection point 36; a positive pole line 33 for connecting the connection point 36 and the starter generator 16 to each other; a positive pole line 34 for connecting the connection point 36 and the lithium ion battery 31 to each other; a positive pole line 35 for connecting the connection point 36 and the lead battery 32 to each other; and a power generation control part for increasing a power generation voltage of the starter generator 16 more than a voltage resistance of the lead battery 32, when the starter generator 16 is controlled to a regenerative power generation state. Electric resistance values of the positive pole line 33 and the positive pole line 35 make an applied voltage to the lead battery 32 lower than the voltage resistance, when the power generation voltage of the starter generator 16 is made bigger than the voltage resistance.SELECTED DRAWING: Figure 2

Description

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

  As a vehicle power supply device mounted on a vehicle, a power supply device that regeneratively generates a generator such as an ISG (integrated starter generator) during vehicle deceleration has been proposed (see Patent Document 1). The power supply device described in Patent Document 1 includes a lead battery and a lithium ion battery that are connected in parallel as a power storage unit. Thereby, not only a lead battery but a lithium ion battery can be charged with regenerative electric power, and regenerative electric power can be increased and the energy efficiency of a vehicle can be improved.

JP 2014-36557 A

  By the way, withstand voltage is set as an upper limit voltage that can be applied to devices such as lead batteries and electric devices provided in the power supply device. For this reason, when the generator is regeneratively generated, it is necessary to control the generated voltage so as to be lower than the withstand voltage. That is, since the generated voltage is limited by the withstand voltage, it has been difficult to increase the regenerative power and increase the energy efficiency of the vehicle.

  An object of the present invention is to increase the energy efficiency of a vehicle by increasing regenerative power.

  The vehicle power supply device of the present invention is a vehicle power supply device mounted on a vehicle, and includes a generator connected to an engine, a power storage unit connected to the generator via a connection point, and the generator A device connected via the connection point, a first energization path that connects the connection point and the generator, a second energization path that connects the connection point and the power storage unit, and A third energization path that connects the connection point and the device to each other; and a power generation control unit that raises the power generation voltage of the generator above the withstand voltage of the device when the generator is controlled to a regenerative power generation state; The electrical resistance values of the first energization path and the third energization path are such that when the power generation voltage of the generator is increased above the withstand voltage, the voltage applied to the device is less than the withstand voltage. The electrical resistance value to decrease

  ADVANTAGE OF THE INVENTION According to this invention, the generated voltage of a generator can be raised rather than the withstand voltage of a device, without impairing durability of a device. Thereby, regenerative electric power can be increased and the energy efficiency of a vehicle can be improved.

It is the schematic which shows the vehicle by which the vehicle power supply device which is one embodiment of this invention is mounted. It is a circuit diagram which shows an example of a power supply circuit. It is a figure which shows an example of the electric current supply condition when controlling a starter generator to a combustion electric power generation state. It is a figure which shows an example of the electric current supply condition when controlling a starter generator to a power generation stop state. It is a figure which shows an example of an electric current supply condition when controlling a starter generator to a regenerative electric power generation state. It is a figure which shows an example of the voltage drop condition in each site | part of a power supply circuit. It is a circuit diagram which shows an example of the power supply circuit with which the vehicle power supply device which is other embodiment of this invention is provided. It is a circuit diagram which shows an example of the power supply circuit with which the vehicle power supply device which is other embodiment of this invention is provided. It is a figure which shows an example of the voltage drop condition in each site | part of a power supply circuit.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a schematic diagram showing a vehicle 11 equipped with a vehicle power supply device 10 according to an embodiment of the present invention. As shown in FIG. 1, a power unit 13 including an engine 12 is mounted on the vehicle 11. A starter generator (generator) 16 is mechanically connected to the crankshaft 14 of the engine 12 via a belt mechanism 15. Further, 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 not only functions as a generator driven by the crankshaft 14, but also functions as an electric motor that starts and rotates the crankshaft 14 in idling stop control or the like. The starter generator 16 includes a stator 21 having a stator coil and a rotor 22 having a field coil. The starter generator 16 is provided with an ISG controller 23 including an inverter, a regulator, a computer, and the like in order to control the energization state of the stator coil and the field coil. The ISG controller 23 controls the energization state of the field coil and the stator coil, and the generated voltage of the starter generator 16 and the like are controlled.

[Power supply circuit]
The power supply circuit 30 provided in the vehicle power supply device 10 will be described. FIG. 2 is a circuit diagram showing an example of the power supply circuit 30. As shown in FIG. 2, the power supply circuit 30 includes a lithium ion battery (power storage unit) 31 that is electrically connected to the starter generator 16, and a lead battery (device) that is electrically connected to the starter generator 16 in parallel therewith. , Second power storage body) 32. The lithium ion battery 31 and the lead battery 32 are set with a withstand voltage as an upper limit voltage that can be applied from the viewpoint of suppressing deterioration such as capacity reduction and output reduction. In order to positively discharge the lithium ion battery 31, the terminal voltage of the lithium ion battery 31 is designed to be higher than the terminal voltage of the lead battery 32. Further, in order to positively charge and discharge the lithium ion battery 31, the internal resistance of the lithium ion battery 31 is designed to be smaller than the internal resistance of the lead battery 32.

  A positive line (first energization path) 33 is connected to the positive terminal 16 a of the starter generator 16, and a positive line (second energization path) 34 is connected to the positive terminal 31 a of the lithium ion battery 31. A positive line (third energization path) 35 is connected to the terminal 32a. These positive electrode lines 33 to 35 are connected to each other through a connection point 36. A negative electrode line 37 is connected to the negative electrode terminal 31 b of the lithium ion battery 31, a negative electrode line 38 is connected to the negative electrode terminal 32 b of the lead battery 32, and a negative electrode line 39 is connected to the negative electrode terminal 16 b of the starter generator 16. The These negative electrode lines 37 to 39 are connected to the reference potential point 40.

  The positive electrode line 34 of the lithium ion battery 31 is provided with a switch SW1 that can be switched between a conduction state and a cutoff state. The positive line 35 of the lead battery 32 is provided with a switch SW2 that can be switched between a conductive state and a cut-off state. These switches SW1 and SW2 are controlled by a battery controller 45 and a main controller 50 described later. The switches SW1 and SW2 are switches composed of semiconductor elements such as MOSFETs, but may be switches that mechanically open and close the contacts using electromagnetic force or the like. The switches SW1 and SW2 are also called relays, contactors and the like.

  An electric device group 43 including a plurality of electric devices 42 is connected to the positive electrode line 35 of the lead battery 32 via the positive electrode line 41. Examples of the electric device 42 constituting the electric device group 43 include a skid prevention device, an electric power steering, and a headlight. Although not shown, various controllers such as an ISG controller 23 and a main controller 50 described later are also connected to the positive electrode line 35 of the lead battery 32 as an electric device 42. In order for these electric devices 42 to function normally without damaging electronic components, a withstand voltage is set as an upper limit voltage that can be applied.

  As shown in FIG. 1, the power supply circuit 30 is provided with a battery module 44. The battery module 44 incorporates a lithium ion battery 31 and a switch SW1. The battery module 44 is provided with a battery controller 45 made of a computer or the like. The battery controller 45 has a function of monitoring the state of charge SOC, charge / discharge current, terminal voltage, cell temperature, and the like of the lithium ion battery 31, and a function of controlling the switch SW1. A battery sensor 46 is provided on the negative electrode line 38 of the lead battery 32. The battery sensor 46 has a function of detecting the state of charge SOC, charge / discharge current, terminal voltage, and the like of the lead battery 32. The positive line 35 is provided with a fuse 47 that protects the electrical device group 43 and the like.

[Power generation control of starter generator]
In order to control the power generation voltage of the starter generator 16, the vehicle power supply device 10 is provided with a main controller (power generation control unit) 50 including a computer or the like. The main controller 50 and the controllers 23 and 45 described above are connected to each other via a vehicle-mounted network 51 such as CAN or LIN so as to be communicable with each other.

  Main controller 50 sets a target power generation voltage of starter generator 16 based on the state of charge SOC of lithium ion battery 31. Then, the main controller 50 outputs a target power generation voltage to the ISG controller 23. The ISG controller 23 controls the power generation voltage of the starter generator 16 according to the target power generation voltage, and controls the starter generator 16 to the combustion power generation state or the power generation halt state. Thus, by controlling the starter generator 16 to the combustion power generation state or the power generation halt state based on the state of charge SOC of the lithium ion battery 31, charging and discharging of the lithium ion battery 31 is controlled as will be described later. The state of charge (SOC) is the ratio of the amount of stored electricity to the design capacity of the battery. The state of charge SOC is transmitted from the battery controller 45 to the main controller 50.

  FIG. 3 is a diagram illustrating an example of a current supply state when the starter generator 16 is controlled to the combustion power generation state. For example, when the state of charge SOC of the lithium ion battery 31 falls below a predetermined lower limit value, the starter generator 16 is driven to generate power by engine power in order to charge the lithium ion battery 31 and increase the state of charge SOC. Thus, when the starter generator 16 is controlled to the combustion power generation state (normal power generation state), the power generation voltage of the starter generator 16 is raised and the power generation voltage applied to the lithium ion battery 31 is adjusted to be higher than the terminal voltage. Is done. As a result, as indicated by the black arrows in FIG. 3, current is supplied from the starter generator 16 to the lithium ion battery 31, the electric device group 43, the lead battery 32, and the like, and the lithium ion battery 31 and the lead battery 32 are thereby supplied. Is slowly charged.

  FIG. 4 is a diagram illustrating an example of a current supply state when the starter generator 16 is controlled to the power generation halt state. For example, when the state of charge SOC of the lithium ion battery 31 exceeds a predetermined upper limit value, the power generation drive of the starter generator 16 by engine power is suspended in order to positively discharge the lithium ion battery 31. As described above, when the starter generator 16 is controlled to the power generation halt state, the power generation voltage of the starter generator 16 is lowered and the power generation voltage applied to the lithium ion battery 31 is adjusted to be lower than the terminal voltage. As a result, as indicated by black arrows in FIG. 4, current is supplied from the lithium ion battery 31 to the electric device group 43, so that the power generation drive of the starter generator 16 can be suppressed or stopped, and the engine load can be reduced. Can be reduced.

  As described above, the main controller 50 controls the starter generator 16 to the combustion power generation state or the power generation halt state based on the state of charge SOC. However, when the vehicle decelerates, the main controller 50 can recover a large amount of kinetic energy and improve fuel efficiency. is necessary. Therefore, when the vehicle decelerates, the power generation voltage of the starter generator 16 is greatly increased, and the starter generator 16 is controlled to the regenerative power generation state. Thereby, since the electric power generated by the starter generator 16 can be increased, the kinetic energy can be actively converted into electric energy and recovered, and the energy efficiency of the vehicle 11 can be improved and the fuel efficiency performance can be improved. it can.

  As described above, whether or not to control the starter generator 16 to the regenerative power generation state is determined based on the operation state of the accelerator pedal and the brake pedal. That is, during coasting when the accelerator pedal is released or when the vehicle is braked when the brake pedal is depressed, the fuel is cut by the engine 12 and the vehicle 11 decelerates, and a lot of kinetic energy is released from the vehicle 11. Therefore, the starter generator 16 is controlled to the regenerative power generation state. On the other hand, in acceleration traveling and steady traveling in which the accelerator pedal is depressed, the fuel injection of the engine 12 is performed, and not much kinetic energy is released from the vehicle 11, so the starter generator 16 generates combustion power. It is controlled to the state and the power generation halt state.

  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. In addition, the black arrow shown in FIG. 5 is an arrow which shows the flow direction of an electric current, and is shown so thickly that the electric current increases. When the starter generator 16 is controlled to be in the regenerative power generation state, the power generation voltage of the starter generator 16 is raised more than the combustion power generation state described above, and the power generation voltage applied to the lithium ion battery 31 is greatly raised above the terminal voltage. . As a result, as indicated by the solid arrows in FIG. 5, since a large current is supplied from the starter generator 16 to the lithium ion battery 31 and the lead battery 32, the lithium ion battery 31 and the lead battery 32 rapidly Charged. Further, since the internal resistance of the lithium ion battery 31 is smaller than the internal resistance of the lead battery 32 or the electric equipment group 43, most of the generated current is supplied to the lithium ion battery 31.

  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 halt state, the switches SW <b> 1 and SW <b> 2 are kept in a conductive state. That is, in the vehicle power supply device 10, charging / discharging of the lithium ion battery 31 can be controlled only by controlling the power generation voltage of the starter generator 16 without performing switching control of the switches SW <b> 1 and SW <b> 2. Thereby, charging / discharging of the lithium ion battery 31 can be easily controlled, and durability of the switches SW1 and SW2 can be improved.

[Voltage drop in regenerative power generation and combustion power generation]
FIG. 6 is a diagram illustrating an example of a voltage drop situation in each part of the power supply circuit 30. FIG. 6 shows a voltage drop situation when the starter generator 16 is controlled to a combustion power generation state or a regenerative power generation state. In FIG. 6, a voltage drop from the positive terminal 16 a of the starter generator 16 to the connection point 36, that is, a voltage drop in the positive line (first energization path) 33 is indicated by a solid line L <b> 1. The voltage drop from the lithium ion battery 31 to the positive electrode terminal 31a, that is, the voltage drop in the positive electrode line (second energization path) 34 is indicated by a broken line L2. A voltage drop from the connection point 36 to the positive electrode terminal 32a of the lead battery 32, that is, a voltage drop in the positive electrode line (third energization path) 35 is indicated by a one-dot chain line L3. 6, the positive electrode terminal 16a of the starter generator 16 is indicated by reference numeral P1, the connection point 36 is indicated by reference numeral P2, the positive electrode terminal 31a of the lithium ion battery 31 is indicated by reference numeral P3, and lead The positive terminal 32a of the battery 32 is indicated by reference numeral P4.

  As described above, when the vehicle decelerates, the kinetic energy of the vehicle 11 is converted into electric energy and recovered, so that the starter generator 16 is controlled to the regenerative power generation state. In this regenerative power generation state, in order to recover a large amount of kinetic energy, it is necessary to greatly increase the power generation voltage of the starter generator 16. However, excessively increasing the power generation voltage of the starter generator 16 is a factor for applying a voltage exceeding the withstand voltage Pbmax to the lead battery 32, and a factor for promoting the deterioration of the lead battery 32. For this reason, the generated voltage of the starter generator 16 is generally limited to the withstand voltage Pbmax or less of the lead battery 32 from the viewpoint of suppressing the deterioration of the lead battery 32.

  Therefore, in the vehicle power supply device 10 according to one embodiment of the present invention, in order to increase the regenerative power while suppressing deterioration of the lead battery 32, the target power generation voltage of the starter generator 16 is set as shown below. In addition, the electrical resistance values of the positive electrode lines 33 and 35 are set. That is, as indicated by reference sign a1 in FIG. 6, when the starter generator 16 is controlled to the regenerative power generation state, the target power generation voltage of the starter generator 16 is set to V1 that exceeds the withstand voltage Pbmax of the lead battery 32. 6, even if the power generation voltage of the starter generator 16 is increased to V1, the starter generator 16 and the starter generator 16 are arranged so that the applied voltage VPb to the lead battery 32 is lower than the withstand voltage Pbmax. Electric resistance values of the positive lines 33 and 35 connecting the lead battery 32 are set.

  That is, as indicated by reference numeral a1 in FIG. 6, even when the power generation voltage of the starter generator 16 is increased to V1, the applied voltage VPb of the lead battery 32 is the withstand voltage as indicated by reference numeral a2 in FIG. The voltage is lowered in the process of current flowing through the positive electrode line 33, the connection point 36, and the positive electrode line 34 so as to be lower than Pbmax. As described above, by increasing the electric resistance values of the positive electrode lines 33 and 35, it is possible to significantly increase the power generation voltage of the starter generator 16 while suppressing the applied voltage VPb of the lead battery 32 to be equal to or lower than the withstand voltage Pbmax. Thereby, deterioration of the lead battery 32 can be suppressed, and the regenerative power of the starter generator 16 can be dramatically increased. In addition, the electrical resistance value of the positive electrode lines 33 and 35 which are electric wires can be adjusted by changing the length and thickness of the positive electrode lines 33 and 35, or selecting the material of the positive electrode lines 33 and 35 as appropriate. .

  By the way, increasing the electrical resistance value of the positive electrode lines 33 and 35 is a factor that decreases the transmission efficiency of the generated current. Therefore, when the starter generator 16 is controlled to the combustion power generation state, the energy associated with the decrease in the transmission efficiency. It is necessary to minimize losses. Therefore, as indicated by reference sign b <b> 1 in FIG. 6, when the starter generator 16 is controlled to the combustion power generation state, the target power generation voltage of the starter generator 16 is set to V <b> 2 that is lower than the withstand voltage Pbmax of the lead battery 32. Thus, in the combustion power generation state, by reducing the power generation voltage to V2, the power generation current can be significantly reduced as compared with the time of regenerative power generation. That is, even when the electrical resistance values of the positive electrode lines 33 and 35 are increased, the current flowing through the positive electrode line 33 and the positive electrode line 34 can be reduced as shown in FIG. The accompanying energy loss can be minimized. Thereby, even when the starter generator 16 is controlled to the combustion power generation state, the fuel energy supplied to the engine 12 can be efficiently converted into electric energy.

  As described above, in the combustion power generation state of the starter generator 16, that is, in the situation where the starter generator 16 is driven to generate power by engine power, the power generation voltage V2 of the starter generator 16 is reduced below the withstand voltage Pbmax of the lead battery 32. . Thereby, even if it is a case where the electrical resistance value of the positive electrode lines 33 and 35 is high, a power generation current can be decreased and the fall of power transmission efficiency can be suppressed, and the energy loss accompanying the fall of power transmission efficiency can be suppressed. it can. That is, the amount of voltage drop from the starter generator 16 to the lead battery 32 or the lithium ion battery 31 can be kept small.

  On the other hand, in the regenerative power generation state of the starter generator 16, that is, in the situation where the starter generator 16 is driven to generate power by the kinetic energy of the vehicle 11, the generated voltage V 1 of the starter generator 16 is raised above the withstand voltage Pbmax of the lead battery 32. In this case, the power generation current of the starter generator 16 increases, the power transmission efficiency decreases, and the energy loss during regenerative power generation increases. However, the regenerative power generation executed when the vehicle 11 decelerates when the kinetic energy of the vehicle 11 is lost is a power generation mode in which kinetic energy is converted into electric energy and recovered. Therefore, even if the energy loss increases, the energy recovery amount, that is, power generation It is important to increase the power. Thus, in the regenerative power generation state of the starter generator 16, although the energy loss increases, the generated power can be significantly increased. Thereby, more kinetic energy can be collect | recovered and the fuel consumption performance of the vehicle 11 can be improved.

  In the above description, the target power generation voltage at the time of regenerative power generation is set and the electric resistance values of the positive electrode lines 33 and 35 are set so that the applied voltage VPb to the lead battery 32 does not exceed the withstand voltage Pbmax. It is not limited to this. For example, as indicated by reference sign c1 in FIG. 6, the target power generation voltage during regenerative power generation is set and the electrical resistance value of the positive electrode line 33 is set so that the applied voltage Vc to the connection point 36 does not exceed the withstand voltage Pbmax You may do it. Thus, by lowering the applied voltage Vc at the connection point 36 below the withstand voltage Pbmax, the applied voltage VPb of the lead battery 32 can be reliably lowered below the withstand voltage Pbmax. 6, in the regenerative power generation state of the starter generator 16, the voltage VLi is applied to the lithium ion battery 31, and the applied voltage VLi is lower than the withstand voltage of the lithium ion battery 31. Needless to say.

  In the above description, since the withstand voltage Pbmax of the lead battery 32 is lower than the withstand voltage of the electric device 42, the generated voltage and the electric resistance value are set based on the withstand voltage Pbmax of the lead battery 32. . That is, when the withstand voltage of the electric device 42 is lower than the withstand voltage Pbmax of the lead battery 32, the generated voltage and the electric resistance value are set based on the withstand voltage of the electric device 42. When the withstand voltage of the electric device 42 is lower than the withstand voltage Pbmax of the lead battery 32, the electric device 42 functions as a device constituting the present invention.

[Other embodiments]
In the above description, from the viewpoint of suppressing deterioration of the lead battery 32, the power generation voltage of the starter generator 16 is set based on the withstand voltage Pbmax of the lead battery 32, and the electric resistance values of the positive lines 33 and 35 are set. However, it is not limited to this. That is, the present invention can be effectively applied even to a vehicle power supply device that does not include the lead battery 32. Here, FIG. 7 is a circuit diagram showing an example of a power supply circuit 61 provided in the vehicle power supply device 60 according to another embodiment of the present invention. In FIG. 7, parts and members similar to the parts and members shown in FIG.

  As shown in FIG. 7, the power supply circuit 61 includes a lithium ion battery 31 that is electrically connected to the starter generator 16, and an electric device (device) 62 that is electrically connected to the starter generator 16 in parallel with the lithium ion battery 31. It has. Examples of the electric device 62 include a skid prevention device, an electric power steering, and a headlight. In order for the electric device 62 to function normally without damaging electronic components or the like, a withstand voltage Emax is set as an upper limit voltage that can be applied.

  A positive line (first energization path) 33 is connected to the positive terminal 16 a of the starter generator 16, and a positive line (second energization path) 34 is connected to the positive terminal 31 a of the lithium ion battery 31. A positive line (third energization path) 63 is connected to the terminal 62a. These positive electrode lines 33, 34, and 63 are connected to each other through a connection point 36. A negative electrode line 37 is connected to the negative electrode terminal 31 b of the lithium ion battery 31, a negative electrode line 64 is connected to the negative electrode terminal 62 b of the electric device 62, and a negative electrode line 39 is connected to the negative electrode terminal 16 b of the starter generator 16. The These negative electrode lines 37, 39 and 64 are connected to the reference potential point 40.

  Thus, even if it is the power supply circuit 30 provided with the electric equipment 62 instead of the lead battery 32 mentioned above as a device connected in parallel with the lithium ion battery 31, it is an electric equipment from a viewpoint of making the electric equipment 62 function normally. Based on the withstand voltage Emax of 62, the power generation voltage of the starter generator 16 is set, and the electric resistance values of the positive lines 33 and 63 are set. That is, when controlling the starter generator 16 to the regenerative power generation state, the target power generation voltage of the starter generator 16 is set to a voltage that exceeds the withstand voltage Emax of the electrical device 62. And even if it is a case where the electric power generation voltage of the starter generator 16 is raised to the target electric power generation voltage, the positive electrode line which connects the starter generator 16 and the electric equipment 62 so that the applied voltage with respect to the electric equipment 62 may be less than the withstand voltage Emax. Electric resistance values 35 and 63 are set. Thereby, regenerative electric power can be increased, making the electric equipment 62 function normally. Further, in the combustion power generation state of the starter generator 16, the power generation voltage of the starter generator 16 is lowered from the withstand voltage Emax of the electric device 62. Thereby, even if it is a case where the electrical resistance value of the positive electrode lines 35 and 63 is high, a generated current can be decreased and the fall of power transmission efficiency can be suppressed, and the energy loss accompanying the fall of power transmission efficiency can be suppressed. it can.

  In the above description, the target power generation voltage at the time of regenerative power generation is set and the electric resistance values of the positive lines 35 and 63 are set so that the applied voltage to the electric device 62 does not exceed the withstand voltage Emax. It is not limited to. For example, the target power generation voltage during regenerative power generation may be set and the electrical resistance value of the positive electrode line 33 may be set so that the applied voltage to the connection point 36 does not exceed the withstand voltage Emax. Thus, by lowering the applied voltage at the connection point 36 below the withstand voltage Emax, the applied voltage of the electrical device 62 can be reliably lowered below the withstand voltage Emax.

[Other embodiments]
As shown in FIG. 6, when the starter generator 16 is controlled to be in the regenerative power generation state, the power generation voltage of the starter generator 16 is increased to V1, but this power generation voltage V1 is based on experiments, simulations, and the like. It may be a value set in advance, or may be a value that changes based on the voltage applied to the lead battery 32 or the connection point 36.

  FIG. 8 is a circuit diagram showing an example of a power supply circuit 71 provided in a vehicle power supply device 70 according to another embodiment of the present invention. In FIG. 8, parts and members that are the same as the parts and members shown in FIG. FIG. 9 is a diagram illustrating an example of a voltage drop situation in each part of the power supply circuit 71. FIG. 9 shows a voltage drop situation when the starter generator 16 is controlled to the regenerative power generation state. The voltage drop from the starter generator 16 to the lead battery 32 through the connection point 36, that is, the first and the second A voltage drop in the positive lines 33 and 35 constituting the third energization path is indicated by solid lines Lx and Ly. In FIG. 9, the same parts as those shown in FIG. 6 are denoted by the same reference numerals, and the description thereof is omitted.

  As shown in FIG. 8, the power supply circuit 71 is provided with a voltage sensor (voltage detection unit) 72 that detects a voltage VPb applied to the positive terminal 32 a of the lead battery 32. The applied voltage VPb detected by the voltage sensor 72 is transmitted to the main controller 50 that controls the generated voltage of the starter generator 16. When the starter generator 16 is controlled to be in the regenerative power generation state, the main controller 50 increases the power generation voltage of the starter generator 16 within a range where the applied voltage VPb does not exceed the withstand voltage Pbmax of the lead battery 32. That is, as indicated by reference signs a1 and a2 in FIG. 9, the generated voltage of the starter generator 16 is raised to V1a so that the voltage VPb applied to the lead battery 32 approaches the withstand voltage Pbmax. Thereby, regenerative electric power of starter generator 16 can be increased to the maximum while suppressing deterioration of lead battery 32.

  In the above description, the power generation voltage of the starter generator 16 is increased within a range where the applied voltage VPb to the lead battery 32 does not exceed the withstand voltage Pbmax. However, the present invention is not limited to this. However, the generated voltage of the starter generator 16 may be raised within a range that does not exceed the withstand voltage Pbmax.

  As shown in FIG. 8, the power supply circuit 71 is provided with a voltage sensor (voltage detection unit) 73 that detects the voltage Vc applied to the connection point 36. The applied voltage Vc detected by the voltage sensor 73 is transmitted to the main controller 50 that controls the generated voltage of the starter generator 16. When the starter generator 16 is controlled to be in the regenerative power generation state, the main controller 50 increases the power generation voltage of the starter generator 16 within a range where the applied voltage Vc does not exceed the withstand voltage Pbmax of the lead battery 32. That is, as indicated by reference numerals b1 and b2 in FIG. 9, the generated voltage of the starter generator 16 is raised to V1b so that the applied voltage Vc applied to the connection point 36 approaches the withstand voltage Pbmax. Thereby, the regenerative power of the starter generator 16 can be increased while suppressing the deterioration of the lead battery 32.

  In the example shown in FIG. 8, the two voltage sensors 72 and 73 are provided in the power supply circuit 71, but the present invention is not limited to this. For example, when the generated voltage is controlled based on the applied voltage VPb, only the voltage sensor 72 may be provided, and when the generated voltage is controlled based on the applied voltage Vc, only the voltage sensor 73 may be provided. good. The voltage sensor 72 detects the applied voltage VPb of the lead battery 32. However, the present invention is not limited to this. The battery sensor 46 described above may detect the applied voltage VPb of the lead battery 32. In the example shown in FIG. 8, the lead battery 32 is provided as a device in the power supply circuit 71. However, the present invention is not limited to this, and the above-described electric devices 42 and 62 may be provided as devices.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. In the above description, the lithium ion battery 31 is used as the power storage unit and the lead battery 32 is used as the second power storage unit. However, the present invention is not limited to this, and other types of batteries and capacitors are used. May be. Each power storage unit is not limited to a different type of power storage unit, and may be the same type of power storage unit. In the above description, the starter generator 16 is employed as the generator, but the present invention is not limited to this, and a generator that does not function as an electric motor may be employed. In the above description, the main controller 50 functions as a power generation control unit. However, the present invention is not limited to this, and it goes without saying that another controller may function as a power generation control unit.

  In the example shown in the figure, the switch SW1 is provided in the positive electrode line 34 of the lithium ion battery 31, but the present invention is not limited to this. For example, a switch SW1 may be provided in the negative electrode line 37 of the lithium ion battery 31 as indicated by a one-dot chain line in FIG. Further, in the illustrated example, the switch SW1 is provided from the viewpoint of stopping charging / discharging when an abnormality occurs in the lithium ion battery 31, and the switch SW2 from the viewpoint of preventing an instantaneous voltage drop, that is, an instantaneous drop in the electrical device group 43. However, the present invention is not limited to this, and the switch SW1 and the switch SW2 may be deleted from the power supply circuit 30.

DESCRIPTION OF SYMBOLS 10 Vehicle power supply device 11 Vehicle 12 Engine 16 Starter generator (generator)
31 Lithium ion battery (power storage unit)
32 Lead battery (device, second battery)
33 Positive line (first energization path)
34 Positive line (second energization path)
35 Positive line (third energization path)
36 Connection point 50 Main controller (power generation control unit)
60 Vehicle Power Supply Device 62 Electric Equipment (Device)
63 Positive line (third energization path)
70 Vehicle Power Supply Device 72 Voltage Sensor (Voltage Detection Unit)
73 Voltage sensor (voltage detector)

Claims (7)

A vehicle power supply device mounted on a vehicle,
A generator coupled to the engine;
A power storage unit connected to the generator via a connection point;
A device connected to the generator via the connection point;
A first energization path connecting the connection point and the generator to each other;
A second energization path connecting the connection point and the power storage unit to each other;
A third energization path connecting the connection point and the device to each other;
When controlling the generator to a regenerative power generation state, a power generation control unit that raises the power generation voltage of the generator above the withstand voltage of the device;
Have
The electrical resistance values of the first energization path and the third energization path are electrical resistances that lower the applied voltage to the device below the withstand voltage when the power generation voltage of the generator is increased above the withstand voltage. Value, the vehicle power supply. The vehicle power supply device according to claim 1,
The electric resistance value of the first energization path is an electric resistance value that lowers the applied voltage to the connection point below the withstand voltage when the generated voltage of the generator is raised above the withstand voltage. Power supply. In the vehicle power supply device according to claim 1 or 2,
The power generation control unit controls the generator in a regenerative power generation state in which the power generation voltage of the generator is increased above the withstand voltage and a normal power generation state in which the power generation voltage of the generator is reduced below the withstand voltage. A vehicle power supply device. In the vehicle power supply device according to claim 3,
When the generator is controlled to be in a regenerative power generation state, fuel cut of the engine is performed. On the other hand, when the generator is controlled to be in a normal power generation state, fuel injection of the engine is performed. Vehicle power supply. In the vehicle power supply device according to any one of claims 1 to 4,
The device is a vehicular power supply device, which is an electrical device or a second power storage unit. In the vehicle power supply device according to any one of claims 1 to 5,
A voltage detector for detecting an applied voltage to the device;
The vehicle power supply device, wherein the power generation control unit raises the power generation voltage of the generator above the withstand voltage in a range where the applied voltage transmitted from the voltage detection unit does not exceed the withstand voltage. In the vehicle power supply device according to any one of claims 1 to 5,
A voltage detector for detecting an applied voltage to the connection point;
The vehicle power supply device, wherein the power generation control unit raises the power generation voltage of the generator above the withstand voltage in a range where the applied voltage transmitted from the voltage detection unit does not exceed the withstand voltage.

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