JP2010120515A - Vehicle power supply unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vehicle power supply unit capable of effectively utilizing a regenerative electric power while restricting a consumption of electrical power at an electric load. <P>SOLUTION: PWM control unit 162 makes a duty ratio variable in response to a battery voltage Vb and performs a PWM control (control under a specified output voltage) in such a way that the output voltage becomes a specified value in the case where the battery voltage Vb is higher than a first threshold voltage V1 and lower than a second threshold voltage V2 under a state that a vehicle performs a regular driving (for example, under a specified velocity) or an accelerated driving. In addition, in the case where a vehicle is running under its decelerated velocity and a generated voltage of an alternator 11 is VH or higher than its approximate value and further the battery voltage Vb is higher than a second threshold voltage V2, the PWM control unit 162 performs a PWM control (a control under a high voltage) with a duty ratio of 100%. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a vehicle power supply device including an in-vehicle generator in which a generated voltage decreases or increases in accordance with acceleration or deceleration of a vehicle, and an in-vehicle battery charged by electric power generated by the in-vehicle generator.

  A power supply device for a vehicle such as an automobile includes an alternator (on-vehicle generator, AC generator), a battery, and the like. The electric power generated by the alternator in conjunction with the engine is used for charging the battery and is supplied to an electric load mounted on the vehicle. In general, the power generation voltage of the alternator is about 14 V and the battery voltage is about 12.8 V, but the output voltage of the vehicle power supply device varies depending on the usage state of the electric load. For this reason, even when the output voltage of the vehicle power supply device fluctuates, the function of the electric load is designed to operate normally.

On the other hand, in order to improve fuel efficiency, vehicles are equipped with a charge control system. The charging control system reduces engine load and lowers fuel consumption by adjusting the power generation voltage of the alternator according to the driving conditions of the vehicle (for example, acceleration, deceleration, constant speed, idling, etc.) (See Non-Patent Document 1).
Harrier New Car Manual, Toyota Motor Corporation, issued February 7, 2003

  In the conventional charge control system, for example, when the vehicle is accelerating, the generator voltage of the alternator is reduced, the engine load due to power generation is reduced, the fuel consumption of the engine is reduced, and the vehicle is decelerated. If so, the power generation voltage of the alternator is raised to increase the power regeneration efficiency to charge the battery, and this regenerative power is supplied at times other than during deceleration to reduce the fuel consumption of the engine. On the other hand, in order to suppress the power consumption of the electric load, a constant power supply required for demonstrating the required performance is desired, but when the regenerative power is generated during deceleration, the power supply to the electric load is not When stopped, there was a problem that regenerative power could not be used effectively.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a vehicle power supply device that can effectively utilize regenerative power while suppressing power consumption of an electric load.

  A vehicle power supply device according to a first aspect of the present invention is provided for a vehicle including an in-vehicle generator whose generated voltage decreases or increases according to acceleration or deceleration of the vehicle, and an in-vehicle battery that is charged by electric power generated by the in-vehicle generator. The power supply apparatus includes a voltage detection unit that detects a voltage of the in-vehicle battery, and a voltage control unit that controls an output voltage applied from the in-vehicle battery to an electric load having a heater, and the voltage control unit includes the voltage When the voltage detected by the detection unit is higher than a threshold voltage, the output voltage applied to the electric load is configured to be higher than a predetermined value.

  According to a second aspect of the present invention, there is provided the vehicular power supply apparatus according to the first aspect, wherein the voltage control unit is configured to control the output voltage by PWM control, and the voltage detected by the voltage detection unit is higher than a threshold voltage. In this case, the PWM control is performed with a predetermined duty ratio.

  In the vehicular power supply device according to a third aspect of the present invention, in the second aspect, the voltage control unit changes the duty ratio according to the detected voltage when the voltage detected by the voltage detection unit is lower than the threshold voltage. It is configured to maintain a predetermined output voltage.

  According to a fourth aspect of the present invention, there is provided a vehicle power supply apparatus for a vehicle comprising: a vehicle-mounted generator whose generated voltage decreases or increases according to acceleration or deceleration of the vehicle; and a vehicle-mounted battery that is charged by electric power generated by the vehicle-mounted generator. The power supply apparatus includes a voltage control unit that controls an output voltage applied from the in-vehicle battery to an electric load having a heater, and a regenerative state determination unit that determines whether the in-vehicle generator is performing regenerative power generation. The voltage control unit is configured to make the output voltage applied to the electrical load higher than a predetermined value when the regenerative state determination unit determines that regenerative power generation is being performed.

  According to a fifth aspect of the present invention, there is provided the vehicle power supply device according to the fourth aspect, wherein the voltage control unit is configured to control the output voltage by PWM control, and the regenerative state determination unit performs regenerative power generation. When the determination is made, the PWM control is performed with a predetermined duty ratio.

  In this invention, the voltage detection part which detects the voltage of a vehicle-mounted battery, and the voltage control part which controls the output voltage applied to the electric load which has a heater from a vehicle-mounted battery are provided. When the vehicle is in an accelerating state, the power generation voltage of the in-vehicle generator is lowered and the voltage of the in-vehicle battery is lowered. Further, when the vehicle is in a decelerating state, the power generation voltage of the in-vehicle generator rises and the voltage of the in-vehicle battery is increased. When the voltage detected by the voltage detection unit is higher than the threshold voltage, the voltage control unit makes the output voltage applied to the electric load higher than a predetermined value. The predetermined value of the output voltage is, for example, the output voltage when the vehicle is traveling at a constant speed that is neither accelerated nor decelerated. In this case, for example, by setting the threshold voltage to a value that can detect a state in which the voltage of the in-vehicle battery increases due to deceleration of the vehicle, the vehicle is decelerated and the power generation voltage of the in-vehicle generator is increased. When the voltage becomes higher, the output voltage applied to the electric load having the heater can be made higher than a predetermined value. As a result, it is possible to improve the performance of the electrical load (for example, defogging in the case of a defogger) by supplying electric power that increases when the vehicle decelerates to the electrical load having the heater.

  In the present invention, the voltage control unit is configured to control the output voltage by PWM control, and when the voltage detected by the voltage detection unit is higher than the threshold voltage, a predetermined duty ratio (for example, 100%) ) PWM control. The output voltage by PWM control is, for example, an effective value or an average value. As a result, the maximum power is supplied to the electric load having the heater from the electric power that is increased when the vehicle is decelerated, so that the maximum performance can be obtained and the generation of wasteful power consumption can be reduced. it can.

  In the present invention, when the voltage detected by the voltage detector is lower than the threshold voltage, the voltage controller changes the duty ratio according to the detected voltage and maintains a predetermined output voltage. The case where the detected voltage is lower than the threshold voltage is, for example, a case where the vehicle is traveling at a constant speed. In such a case, by making the output voltage applied to the electric load constant, the power consumption of the electric load can be reduced, and fuel efficiency and power saving can be constantly improved.

  In the present invention, a voltage control unit that controls an output voltage applied to an electric load having a heater from a vehicle-mounted battery, and a regenerative state determination unit that determines whether or not the vehicle-mounted generator is performing regenerative power generation. Prepare. The regenerative state determination unit can determine whether or not regenerative power generation is being performed, for example, based on power generation information of an on-vehicle generator or vehicle speed information. When the voltage control unit determines that the regenerative power generation is being performed by the regenerative state determination unit, the voltage control unit makes the output voltage applied to the electric load higher than a predetermined value. The predetermined value of the output voltage is, for example, the output voltage when the vehicle is traveling at a constant speed that is neither accelerated nor decelerated. In this case, for example, when the vehicle decelerates and the power generation voltage of the on-vehicle generator rises, the output voltage applied to the electric load having the heater can be made higher than a predetermined value. As a result, it is possible to improve the performance of the electrical load (for example, defogging in the case of a defogger) by supplying electric power that increases when the vehicle decelerates to the electrical load having the heater.

  In the present invention, the voltage control unit is configured to control the output voltage by PWM control, and when the regenerative state determination unit determines that regenerative power generation is performed, a predetermined duty ratio (for example, 100%) PWM control. The output voltage by PWM control is, for example, an effective value or an average value. As a result, the maximum power is supplied to the electric load having the heater from the electric power that is increased when the vehicle is decelerated, so that the maximum performance can be obtained and the generation of wasteful power consumption can be reduced. it can.

  ADVANTAGE OF THE INVENTION According to this invention, generation | occurrence | production of useless power consumption more than the electric power required for exhibiting performance required for an electrical load can be reduced.

Embodiment 1
Hereinafter, the present invention will be described with reference to the drawings illustrating embodiments. FIG. 1 is a block diagram showing an example of the configuration of a vehicle power supply device 10 according to the present invention. The vehicle power supply device 10 is attached to the alternator 11 as an in-vehicle generator, the alternator 11, a regulator 12 that controls a generated voltage generated by the alternator 11, and a battery 14 as an in-vehicle battery that is charged by the electric power generated by the alternator 11. , A current sensor 15 for detecting a charging current and a discharging current of the battery 14, a charge control ECU (Electronic Control Unit) 13 for controlling charging of the battery 14, and a control unit as a voltage control unit for controlling an output voltage from the battery 14 16 and an FET 17 that repeatedly turns on and off in response to a control signal output from the control unit 16.

  A vehicle speed detector 2 is connected to the charging control ECU 13. A fuse F <b> 0 is provided in the electric circuit between the alternator 11 and the battery 14. An electric circuit for supplying electric power from the alternator 11 and the battery 14 is branched according to the electric load. For example, the defogger 3 as an electric load having a heater is connected to the battery 14 via the fuse F1 and the FET 17. Yes. Similarly, another electric load (not shown) is connected to the battery 14 via the fuse F2. The fuses F0, F1, F2, the control unit 16, the FET 17, and the like are housed in a relay box 1 provided with a relay (not shown). In addition, a switch SW <b> 1 for performing an on / off operation of the defogger 3 is connected to the control unit 16. For example, the switch SW1 can be operated by a driver or a passenger to turn the defogger 3 on and off.

  The control unit 16 includes a microcomputer, a memory, and the like, and includes a voltage detection unit 161 that detects the voltage Vb of the battery 14, a PWM control unit 162 that serves as a voltage control unit that controls on / off of the FET 17 by PWM control, and the like. Yes.

  The configuration of the vehicle power supply device 10 shown in FIG. 1 is an example, and when it is mounted on a vehicle, it can be set as appropriate as to which part or all of the configuration is arranged. Although not shown in FIG. 1, as an electrical load having a heater, a de-focuser 3, a mirror heater, and the like can be provided in a separate electric circuit from the defogger 3.

  Next, the operation of the vehicle power supply device 10 of the present embodiment will be described. The alternator 11 generates power in conjunction with an engine (not shown). The regulator 12 performs constant voltage control or step-up / step-down control on the generated voltage generated by the alternator 11 by adjusting the field current of the alternator 11.

  The alternator 11 rectifies the generated power with a rectifier (not shown) inside the alternator 11 and then charges the battery 14 through the fuse F0 in the relay box 1. The charging current charged in the battery 14 is detected by the current sensor 15 and output to the charging control ECU 13. Further, the charging control ECU 13 detects the voltage Vb of the battery 14.

  The charging control ECU 13 acquires the vehicle speed detected by the vehicle speed detector 2 and determines the traveling state of the vehicle (for example, idling, acceleration traveling, steady traveling, deceleration traveling, etc.) based on the acquired vehicle speed, and the determined traveling Charge control of the battery 14 is performed according to the state.

  FIG. 2 is an explanatory view showing an example of the charge control operation by the charge control ECU 13. As shown in FIG. 2, the running state of the vehicle includes, for example, idling, acceleration running, steady running, and decelerating running. According to each running state, the power generation mode of the alternator 11, the battery capacity of the battery 14, and the alternator 11 generated voltage and vehicle speed pattern are different.

  For example, in the case of acceleration traveling, the power generation voltage of the alternator 11 is lowered from the normal (steady) value VN to VL. As a result, the engine load due to the power generation by the alternator 11 can be reduced, and the fuel consumption of the engine can be reduced.

  On the other hand, in the case of deceleration traveling, the power generation voltage of the alternator 11 is increased from the normal (steady) value VN to VH. Thereby, the electric power generated by the alternator 11 is increased, the charging current to the battery 14 is increased, and the electric power supplied to another electric load (not shown) is increased via the fuse F2.

  In this case, the voltages VL, VN, and VH indicated by the generated voltage in FIG. 2 are about 12.5V, 13.5V, and 14.5V, respectively. The state where the generated voltage is VH is a state where regenerative power is generated. In this embodiment, as will be described later, such regenerative power can be effectively utilized.

  When the switch SW1 for the defogger 3 is turned on, the control unit 16 switches the FET 17 from the off state to the on state, and the PWM control unit 162 according to the voltage Vb of the battery 14 detected by the voltage detection unit 161. Thus, PWM control is performed to turn on and off the FET 17 with a predetermined duty ratio.

  FIG. 3 is an explanatory diagram showing an example of PWM control of the PWM control unit 162. In FIG. 3, the horizontal axis represents the battery voltage Vb, and the vertical axis represents the duty ratio. As shown in FIG. 3, a first threshold voltage V1 (for example, 12V) and a second threshold voltage (for example, 14V) are set or stored in advance as threshold voltages for PWM control. In this case, the first threshold voltage V1 (12V) can be set to a value slightly lower than or equal to the generated voltage VL (for example, 12.5V). Further, the second threshold voltage V2 (14V) can be a value slightly lower than or substantially the same as the generated voltage VH (for example, 14.5V).

  As shown in FIG. 3, when the battery voltage Vb is lower than the first threshold voltage V1, the PWM control unit 162 performs PWM control (low voltage control) with a duty ratio of 100%.

  In addition, when the vehicle is traveling in a steady state (for example, at a constant speed) or accelerating, and the battery voltage Vb is higher than the first threshold voltage V1 and lower than the second threshold voltage V2, the PWM control unit 162 The duty ratio is changed according to the voltage Vb, and PWM control (output voltage constant control) is performed so that the output voltage becomes a predetermined constant value.

  In addition, when the power generation voltage of the alternator 11 is higher than VH or a value close thereto when the vehicle is decelerating and the battery voltage Vb is higher than the second threshold voltage V2, the PWM control unit 162 sets the duty ratio to 100. % PWM control (high voltage control). In this case, the duty ratio is not limited to 100%, and may be a value such as 90% or 85% as long as the ratio is constant.

FIG. 4 is an explanatory diagram showing the transition of the load power supplied to the defogger 3 according to the battery voltage Vb. FIG. 4A shows a change in the running state of the vehicle. As an example, it is assumed that the running state changes in the order of acceleration running, steady running, decelerating running, steady running, decelerating running, and steady running.
In this case, as shown in FIG. 4 (b), the generated voltage of the alternator 11 corresponds to the change in the running state of the vehicle in FIG. 4 (a). Is VN, and the generated voltage is VH in the deceleration state. The time when the power generation voltage of the alternator 11 is VH in the deceleration state is when the regenerative power is generated.

  Further, as shown in FIG. 4C, when the vehicle traveling state is steady traveling or acceleration traveling, the duty ratio is varied so that the output voltage applied to the defogger 3 is constant (predetermined value). PWM control is performed.

  Further, when the vehicle is running at a reduced speed, PWM control is performed with a duty ratio of 100% so that the output voltage applied to the defogger 3 is higher than the output voltage (predetermined value) in the steady state. I do.

  As shown in FIG. 4 (d), the load power supplied to the defogger 3 increases when the vehicle traveling state is decelerating compared to other states (accelerated traveling, steady traveling). For example, a portion indicated by a broken line in FIG. 4D corresponds to surplus power. Thereby, when the power generation voltage of the alternator 11 is VH in the decelerating state, the performance of the defogger 3 (that is, removing fogging) can be improved using the regenerative power. Since the defogger 3 can perform its maximum performance by using the regenerative power in advance, it is possible to remove the fog even if the power generation voltage of the alternator 11 drops below VN. , The effect can be sustained. In addition, since the surplus power can be used to exhibit the performance of the defogger 3, it is possible to reduce consumption as wasted power more than the power required to exhibit the performance required for the electric load.

  In the case of an electric load having a heater as in the defogger 3, when regenerative power is generated, the power supplied to the defogger 3 is temporarily reduced by using the regenerative power to maximize its performance. Even in this case, the effect can be sustained. In the case of an electric load having a heater, if there is a margin in the generated power when the vehicle is decelerated, the surplus power is supplied to the heater to obtain a predetermined function or performance (for example, to remove fog) When the vehicle travels at a constant speed, power consumption by the heater can be reduced, and fuel efficiency can be constantly improved and power can be saved. In addition to the defogger 3, for example, if the load is an electric load that uses electric power such as a deisa and a mirror heater as heat, wasteful power consumption can be reduced by applying this embodiment.

  As described above, in the present embodiment, the PWM control unit 162 performs PWM control with a predetermined duty ratio (for example, 100%) when the battery voltage Vb is higher than the second threshold voltage V2. As a result, the maximum power is supplied to the electric load having a heater such as the defogger 3 from the power (regenerative power) that is increased when the vehicle decelerates, and the maximum performance is obtained and the uselessness is wasted. Generation of power consumption can be reduced.

  Further, when the battery voltage Vb is lower than the second threshold voltage V2, the PWM controller 162 changes the duty ratio according to the battery voltage Vb and maintains a predetermined output voltage. As a result, the output voltage applied to the electric load can be kept constant, the power consumption of the electric load can be reduced, and fuel efficiency can be constantly improved and power can be saved.

Embodiment 2
FIG. 5 is a block diagram illustrating an example of a configuration of the vehicle power supply device 10 according to the second embodiment. The difference from Embodiment 1 is that a regeneration state determination unit 163 is provided. For example, the regenerative state determination unit 163 acquires power generation information of the alternator 11 from the charging control ECU 13 and determines whether the alternator 11 is performing regenerative power generation. The regenerative state determination unit 163 can also acquire vehicle speed information from the vehicle speed detector 2 and determine whether or not the alternator 11 is performing regenerative power generation.

  When the regenerative state determination unit 163 determines that regenerative power generation is being performed, for example, when the power generation voltage of the alternator 11 increases while the vehicle is traveling at a reduced speed, the PWM control unit 162 sets the duty ratio to 100%. PWM control (high voltage control) is performed. In this case, the duty ratio is not limited to 100%, and may be a value such as 90% or 85% as long as the ratio is constant. As described above, when the regenerative state determination unit 163 determines that the regenerative power generation is being performed, the control unit 16 increases the output voltage applied to the defogger 3 above a predetermined value. The predetermined value of the output voltage is, for example, the output voltage when the vehicle is traveling at a constant speed that is neither accelerated nor decelerated. In this case, for example, when the vehicle decelerates and the power generation voltage of the alternator 11 increases, the output voltage applied to the defogger 3 can be made higher than a predetermined value. As a result, it is possible to improve the performance of the electrical load (for example, defogging in the case of a defogger) by supplying electric power that increases when the vehicle decelerates to the electrical load having the heater.

  Further, when the regenerative state determination unit 163 determines that regenerative power generation is not performed, for example, when the power generation voltage of the alternator 11 is not increased in a state where the vehicle is traveling in a steady state (for example, a constant speed) or accelerated. The PWM control unit 162 changes the duty ratio according to the battery voltage Vb, and performs PWM control (constant output voltage control) so that the output voltage becomes a predetermined constant value. As described above, also in the second embodiment, the maximum power is supplied to the electric load having the heater from the electric power that is increased when the vehicle is decelerated, so that the maximum performance is obtained and the uselessness is wasted. Generation of power consumption can be reduced.

  As described above, according to the present invention, the power consumption of the electric load can be reduced, and when the generated voltage becomes high and surplus power is generated while constantly saving power for improving fuel efficiency, By supplying the increased power to the load positively, the performance of the electric load can be maximized and the effect can be maintained.

It is a block diagram which shows an example of a structure of the vehicle power supply device which concerns on this invention. It is explanatory drawing which shows the charge control operation example by charge control ECU. It is explanatory drawing which shows an example of the PWM control of a PWM control part. It is explanatory drawing which shows transition of the load electric power supplied to a defogger according to a battery voltage. FIG. 5 is a block diagram illustrating an example of a configuration of a vehicle power supply device according to a second embodiment.

Explanation of symbols

1 Relay Box 3 Defogger 11 Alternator 12 Regulator 13 Charge Control ECU
14 battery 15 current sensor 16 control unit 161 voltage detection unit 162 PWM control unit 163 regeneration state determination unit 17 FET

Claims (5)

In a vehicle power supply device comprising: an in-vehicle generator in which the generated voltage decreases or increases in accordance with acceleration or deceleration of the vehicle; and an in-vehicle battery that is charged by electric power generated by the in-vehicle generator;
A voltage detector for detecting the voltage of the vehicle battery;
A voltage control unit for controlling an output voltage applied from the vehicle battery to an electric load having a heater,
The voltage controller is
When the voltage detected by the voltage detector is higher than a threshold voltage, the output voltage applied to the electric load is configured to be higher than a predetermined value. The voltage controller is
The output voltage is controlled by PWM control, and when the voltage detected by the voltage detection unit is higher than a threshold voltage, the PWM control is performed with a predetermined duty ratio. Item 4. The vehicle power supply device according to Item 1. The voltage controller is
The configuration according to claim 2, wherein when the voltage detected by the voltage detector is lower than the threshold voltage, the duty ratio is changed according to the detected voltage to maintain a predetermined output voltage. The power supply device for vehicles as described. In a vehicle power supply device comprising: an in-vehicle generator in which the generated voltage decreases or increases in accordance with acceleration or deceleration of the vehicle; and an in-vehicle battery that is charged by electric power generated by the in-vehicle generator;
A voltage control unit for controlling an output voltage applied to an electric load having a heater from the vehicle battery;
A regenerative state determination unit that determines whether or not the in-vehicle generator is performing regenerative power generation,
The voltage controller is
When the regenerative state determination unit determines that regenerative power generation is being performed, the vehicular power supply device is configured so that an output voltage applied to the electric load is higher than a predetermined value. The voltage controller is
The output voltage is controlled by PWM control, and when the regenerative state determination unit determines that regenerative power generation is being performed, the output voltage is controlled by a predetermined duty ratio. The vehicle power supply device according to claim 4.

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